diff --git a/.gitignore b/.gitignore
index d3547270cc6..418b3677b36 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,12 +1,6 @@
-# Downloaded packages and build tools.
-/lkg
-/packages
-/Tools
+# output location
+artifacts/
 
-/tests/scripts/current
-/release
-/debug
-/Proto
 packages/
 
 /tests/scripts/current
@@ -88,9 +82,6 @@ lib/bootstrap/4.1/policy*
 obj/
 bin/
 aclocal.m4
-Debug
-Release
-Proto
 sign_temp
 .libs
 configure
@@ -114,7 +105,6 @@ ossreadme*.txt
 *.cto
 *.vstman
 project.lock.json
-Tools/
 Backup/
 tests/fsharp/core/array/dont.run.peverify
 tests/fsharp/core/innerpoly/dont.run.peverify
@@ -123,7 +113,6 @@ times
 /tests/fsharpqa/testenv/bin/System.ValueTuple.dll
 source_link.json
 .vs/
-/VSRelease/net40/bin
 System.ValueTuple.dll
 tests/fsharpqa/testenv/bin/System.ValueTuple.dll
 */.fake
diff --git a/.vsts-pr.yaml b/.vsts-pr.yaml
index 37246474bf7..44c277a3943 100644
--- a/.vsts-pr.yaml
+++ b/.vsts-pr.yaml
@@ -17,7 +17,7 @@ jobs:
   - script: $(_command) $(_args)
   - task: PublishBuildArtifacts@1
     inputs:
-      PathtoPublish: '$(Build.SourcesDirectory)/tests/TestResults'
+      PathtoPublish: '$(Build.SourcesDirectory)/artifacts/TestResults'
       ArtifactName: 'Linux $(_command) $(_args)'
       publishLocation: Container
     continueOnError: true
@@ -26,7 +26,7 @@ jobs:
 - job: Windows
   pool:
     vmImage: vs2017-win2016
-  timeoutInMinutes: 90
+  timeoutInMinutes: 120
   strategy:
     maxParallel: 7
     matrix:
@@ -55,7 +55,7 @@ jobs:
   - script: $(_command) $(_args)
   - task: PublishBuildArtifacts@1
     inputs:
-      PathtoPublish: '$(Build.SourcesDirectory)\tests\TestResults'
+      PathtoPublish: '$(Build.SourcesDirectory)\artifacts\TestResults'
       ArtifactName: 'Windows $(_command) $(_args)'
       publishLocation: Container
     continueOnError: true
diff --git a/.vsts-signed.yaml b/.vsts-signed.yaml
index a628c4d9e6e..823ac20297a 100644
--- a/.vsts-signed.yaml
+++ b/.vsts-signed.yaml
@@ -36,7 +36,7 @@ jobs:
     displayName: Publish nightly package to MyGet
     inputs:
       scriptName: 'setup\publish-assets.ps1'
-      arguments: '-binariesPath $(BuildConfiguration) -branchName $(Build.SourceBranch) -apiKey $(FSharp.MyGetApiKey)'
+      arguments: '-binariesPath artifacts\bin -configuration $(BuildConfiguration) -branchName $(Build.SourceBranch) -apiKey $(FSharp.MyGetApiKey)'
     condition: and(succeeded(), contains(variables['PB_PublishType'], 'myget'))
 
   # Package publish
@@ -50,12 +50,12 @@ jobs:
     displayName: Publish packages to Azure Blob Storage
     inputs:
       solution: PublishToBlob.proj
-      msbuildArguments: '/t:Build /p:Configuration=$(BuildConfiguration) /p:ExpectedFeedUrl=$(PB_PublishBlobFeedUrl) /p:AccountKey=$(PB_PublishBlobFeedKey) /p:ManifestRepouri=$(Build.Repository.Uri) /p:ManifestBranch=$(Build.SourceBranch) /p:ManifestCommit=$(Build.SourceVersion) /p:ManifestBuildId=$(Build.BuildNumber) /bl:$(Build.SourcesDirectory)/$(BuildConfiguration)/log/publish.binlog'
+      msbuildArguments: '/t:Build /p:Configuration=$(BuildConfiguration) /p:ExpectedFeedUrl=$(PB_PublishBlobFeedUrl) /p:AccountKey=$(PB_PublishBlobFeedKey) /p:ManifestRepouri=$(Build.Repository.Uri) /p:ManifestBranch=$(Build.SourceBranch) /p:ManifestCommit=$(Build.SourceVersion) /p:ManifestBuildId=$(Build.BuildNumber) /bl:$(Build.SourcesDirectory)/artifacts/log/$(BuildConfiguration)/pub/publish.binlog'
     condition: and(succeeded(), contains(variables['PB_PublishType'], 'blob'))
   - task: PublishBuildArtifacts@1
     displayName: Publish publishing bin log
     inputs:
-      PathtoPublish: '$(Build.SourcesDirectory)/$(BuildConfiguration)/log'
+      PathtoPublish: '$(Build.SourcesDirectory)/artifacts/log/$(BuildConfiguration)/pub'
       ArtifactName: 'Publish_bin_log'
       publishLocation: Container
     continueOnError: true
@@ -80,7 +80,7 @@ jobs:
   - task: PublishBuildArtifacts@1
     displayName: Create static drop
     inputs:
-      PathtoPublish: '$(BuildConfiguration)'
+      PathtoPublish: 'artifacts'
       ArtifactName: '$(Build.BuildNumber)'
       publishLocation: FilePath
       TargetPath: '$(DropRoot)\$(Build.DefinitionName)\$(Build.SourceBranchName)'
@@ -94,7 +94,7 @@ jobs:
     inputs:
       SymbolsPath: '$(DropRoot)\$(Build.DefinitionName)\$(Build.SourceBranchName)\$(Build.BuildNumber)\Symbols'
       SearchPattern: '**\*.dll;**\*.exe;**\*.pdb'
-      SymbolsFolder: '$(Build.SourcesDirectory)\$(BuildConfiguration)'
+      SymbolsFolder: '$(Build.SourcesDirectory)\artifacts\SymStore'
       TreatNotIndexedAsWarning: true
       SymbolsProduct: '$(Build.DefinitionName)'
       SymbolsVersion: '$(Build.BuildNumber)'
@@ -105,7 +105,7 @@ jobs:
   - task: ms-vseng.MicroBuildTasks.4305a8de-ba66-4d8b-b2d1-0dc4ecbbf5e8.MicroBuildUploadVstsDropFolder@1
     displayName: Upload VSTS Drop
     inputs:
-      DropFolder: '$(Build.SourcesDirectory)\$(BuildConfiguration)\insertion'
+      DropFolder: '$(Build.SourcesDirectory)\artifacts\VSSetup\$(BuildConfiguration)\Insertion'
     condition: and(succeeded(), contains(variables['PB_PublishType'], 'vsts'))
 
   # Execute cleanup tasks
@@ -127,7 +127,7 @@ jobs:
     displayName: Publish symbols to SymWeb
     inputs:
       symbolServiceURI: 'https://microsoft.artifacts.visualstudio.com/DefaultCollection'
-      sourcePath: '$(DropRoot)\$(Build.DefinitionName)\$(Build.SourceBranchName)\$(Build.BuildNumber)\Symbols'
+      sourcePath: '$(DropRoot)\$(Build.DefinitionName)\$(Build.SourceBranchName)\$(Build.BuildNumber)\SymStore'
       usePat: false
     condition: and(succeeded(), contains(variables['PB_PublishType'], 'symweb'))
 
diff --git a/DEVGUIDE.md b/DEVGUIDE.md
index b1b0d00cbf5..f7a8531cd2d 100644
--- a/DEVGUIDE.md
+++ b/DEVGUIDE.md
@@ -167,12 +167,12 @@ components installed in that VS installation.  You can revert this step by disab
 For **Debug**, uninstall then reinstall:
 
     VSIXInstaller.exe /u:"VisualFSharp"
-    VSIXInstaller.exe debug\net40\bin\VisualFSharpFull.vsix
+    VSIXInstaller.exe artifacts\bin\VisualFSharpFull\Debug\net46\VisualFSharpFull.vsix
 
 For **Release**, uninstall then reinstall:
 
     VSIXInstaller.exe /u:"VisualFSharp"
-    VSIXInstaller.exe release\net40\bin\VisualFSharpFull.vsix
+    VSIXInstaller.exe artifacts\bin\VisualFSharpFull\Release\net46\VisualFSharpFull.vsix
 
 Restart Visual Studio, it should now be running your freshly-built Visual F# IDE Tools with updated F# Interactive.
 
@@ -237,7 +237,7 @@ If you change error messages you may need to update FSComp.fs in `src\buildfroms
 To do this, build the non-buildfromsource version of FSharp.Compiler.Private (src\fsharp\FSharp.Compiler.Private) then check its obj\ directory for `FSComp.fs` and manually copy that into the buildfromsource directory.
 
     .\build net40
-    copy /y src\fsharp\FSharp.Compiler.Private\obj\release\net40\FSComp.* src\buildfromsource\FSharp.Compiler.Private\
+    copy /y artifacts\obj\FSharp.Compiler.Private\Release\net46\FSComp.* src\buildfromsource\FSharp.Compiler.Private\
 
 If your changes involve modifying the list of language keywords in any way, (e.g. when implementing a new keyword), the XLF localization files need to be synced with the corresponding resx files. This can be done automatically by running
 
diff --git a/FSharpBuild.Directory.Build.props b/FSharpBuild.Directory.Build.props
index 81701799796..86f3e9d0974 100644
--- a/FSharpBuild.Directory.Build.props
+++ b/FSharpBuild.Directory.Build.props
@@ -10,9 +10,16 @@
     <Configuration Condition="'$(Configuration)' == ''">Debug</Configuration>
     <RepoRoot>$(MSBuildThisFileDirectory)</RepoRoot>
     <FSharpSourcesRoot>$(RepoRoot)src</FSharpSourcesRoot>
-    <ToolsRoot>$(RepoRoot)Tools</ToolsRoot>
-    <ProtoOutputPath Condition="'$(OS)' != 'Unix'">$(RepoRoot)Proto\net40\bin</ProtoOutputPath>
-    <ProtoOutputPath Condition="'$(OS)' == 'Unix'">$(RepoRoot)Proto\coreclr\bin</ProtoOutputPath>
+    <ArtifactsDir>$(RepoRoot)artifacts</ArtifactsDir>
+    <ToolsRoot>$(ArtifactsDir)\toolset</ToolsRoot>
+    <ArtifactsBinDir>$(ArtifactsDir)\bin</ArtifactsBinDir>
+    <ArtifactsObjDir>$(ArtifactsDir)\obj</ArtifactsObjDir>
+    <ArtifactsPackagesDir>$(ArtifactsDir)\packages</ArtifactsPackagesDir>
+    <BaseOutputPath>$(ArtifactsBinDir)\$(MSBuildProjectName)</BaseOutputPath>
+    <BaseIntermediateOutputPath>$(ArtifactsObjDir)\$(MSBuildProjectName)</BaseIntermediateOutputPath>
+    <SymStoreDirectory>$(ArtifactsDir)\SymStore</SymStoreDirectory>
+    <ProtoOutputPath Condition="'$(OS)' != 'Unix'">$(ArtifactsBinDir)\fsc\Proto\net472</ProtoOutputPath>
+    <ProtoOutputPath Condition="'$(OS)' == 'Unix'">$(ArtifactsBinDir)/fsc/Proto/netcoreapp2.1</ProtoOutputPath>
     <ValueTupleImplicitPackageVersion>4.4.0</ValueTupleImplicitPackageVersion>
   </PropertyGroup>
 
diff --git a/FSharpBuild.Directory.Build.targets b/FSharpBuild.Directory.Build.targets
index 375416e5cf3..fa39d7498fd 100644
--- a/FSharpBuild.Directory.Build.targets
+++ b/FSharpBuild.Directory.Build.targets
@@ -34,42 +34,7 @@
     </CreateItem>
   </Target>
 
-  <Target Name="ComputeFinalOutputPaths">
-    <!--
-    Ideally we'd set <OutputPath> to `$(Configuration)\[net40|coreclr]\bin`, but the calculation of `[net40|coreclr]`
-    depends on the `$(TargetFramework)` variable which is set by the individual project files, but by the time we have
-    that value (e.g., in this file) it's too late; some targets, particularly from the VsSDK have already used the
-    values of $(OutputPath)/$(OutDir).
-
-    The fix is to not set `$(Outputpath)` and simply copy stuff there after the fact.
-    -->
-
-    <PropertyGroup>
-      <TargetDotnetProfile Condition="$(TargetFramework.StartsWith('netstandard')) or $(TargetFramework.StartsWith('netcoreapp'))">coreclr</TargetDotnetProfile>
-      <TargetDotnetProfile Condition="$(TargetFramework.StartsWith('net4'))">net40</TargetDotnetProfile>
-      <ActualOutputPath Condition="'$(Language)' != 'VB'">$(MSBuildProjectDirectory)\$(OutputPath)</ActualOutputPath>
-      <ActualOutputPath Condition="'$(Language)' == 'VB'">$(OutputPath)</ActualOutputPath>
-      <FinalOutputPath>$(RepoRoot)$(Configuration)\$(TargetDotnetProfile)\bin</FinalOutputPath>
-      <FinalIntermediateOutputPath>$(RepoRoot)$(Configuration)\$(TargetDotnetProfile)\obj</FinalIntermediateOutputPath>
-    </PropertyGroup>
-  </Target>
-
-  <Target Name="HACK_CopyOutputsToTheProperLocation"
-          AfterTargets="AfterBuild"
-          DependsOnTargets="ComputeFinalOutputPaths"
-          Condition="'$(DisableOutputPathCopying)' != 'true'">
-
-    <ItemGroup>
-      <OutputFilesToCopy Include="$(ActualOutputPath)**" />
-      <IntermediateFilesToCopy Include="$(IntermediateOutputPath)\**" />
-    </ItemGroup>
-
-    <Message Text="Copying build artifacts to $(FinalOutputPath)" />
-    <MakeDir Directories="$(FinalOutputPath);$(FinalIntermediateOutputPath)" />
-    <Copy SourceFiles="@(OutputFilesToCopy)" DestinationFolder="$(FinalOutputPath)\%(RecursiveDir)" />
-    <Copy SourceFiles="@(IntermediateFilesToCopy)" DestinationFolder="$(FinalIntermediateOutputPath)\%(RecursiveDir)" />
-  </Target>
-
+  <Import Project="build\targets\NGenOrCrossGen.targets" />
   <Import Project="build\targets\ConvertPortablePdbs.targets" />
   <Import Project="build\targets\GenerateAssemblyAttributes.targets" />
   <Import Project="build\targets\GenerateInternalsVisibleTo.targets" />
diff --git a/FSharpTests.Directory.Build.props b/FSharpTests.Directory.Build.props
index eb20065bec2..a8c6542570f 100644
--- a/FSharpTests.Directory.Build.props
+++ b/FSharpTests.Directory.Build.props
@@ -1,48 +1,43 @@
 <Project>
 
-  <!-- SDK targets override -->
-  <PropertyGroup Condition=" '$(FSharpTestCompilerVersion)' == 'net40' ">
-    <_FSharpCompilerPath>$(MSBuildThisFileDirectory)$(Configuration)/net40/bin</_FSharpCompilerPath>
-
+  <PropertyGroup Condition="'$(FSharpTestCompilerVersion)' == 'net40'">
     <DisableAutoSetFscCompilerPath>true</DisableAutoSetFscCompilerPath>
 
-    <FscToolPath>$(_FSharpCompilerPath)</FscToolPath>
+    <FscToolPath>$(MSBuildThisFileDirectory)artifacts\bin\fsc\$(Configuration)\net472</FscToolPath>
     <FscToolExe>fsc.exe</FscToolExe>
     <DotnetFscCompilerPath></DotnetFscCompilerPath>
 
-    <FsiToolPath>$(_FSharpCompilerPath)</FsiToolPath>
+    <FsiToolPath>$(MSBuildThisFileDirectory)artifacts\bin\fsi\$(Configuration)\net472</FsiToolPath>
     <FsiToolExe>fsi.exe</FsiToolExe>
     <DotnetFsiCompilerPath></DotnetFsiCompilerPath>
   </PropertyGroup>
 
-  <!-- SDK targets override -->
-  <PropertyGroup Condition=" '$(FSharpTestCompilerVersion)' == 'coreclr' ">
-    <_FSharpCompilerPath>$(MSBuildThisFileDirectory)$(Configuration)/coreclr/bin</_FSharpCompilerPath>
-
+  <PropertyGroup Condition="'$(FSharpTestCompilerVersion)' == 'coreclr'">
     <DisableAutoSetFscCompilerPath>true</DisableAutoSetFscCompilerPath>
-    <FscToolPath>$(MSBuildThisFileDirectory)Tools/dotnet20</FscToolPath>
+
+    <FscToolPath>$(MSBuildThisFileDirectory)artifacts\toolset\dotnet</FscToolPath>
     <FscToolExe Condition="'$(OS)' != 'Unix'">dotnet.exe</FscToolExe>
     <FscToolExe Condition="'$(OS)' == 'Unix'">dotnet</FscToolExe>
-    <DotnetFscCompilerPath>$(_FSharpCompilerPath)/fsc.exe</DotnetFscCompilerPath>
+    <DotnetFscCompilerPath>$(MSBuildThisFileDirectory)artifacts\bin\fsc\$(Configuration)\netcoreapp2.1\fsc.exe</DotnetFscCompilerPath>
 
-    <FsiToolPath>$(MSBuildThisFileDirectory)Tools/dotnet20</FsiToolPath>
+    <FsiToolPath>$(MSBuildThisFileDirectory)artifacts\toolset\dotnet</FsiToolPath>
     <FsiToolExe Condition="'$(OS)' != 'Unix'">dotnet.exe</FsiToolExe>
     <FsiToolExe Condition="'$(OS)' == 'Unix'">dotnet</FsiToolExe>
-    <DotnetFsiCompilerPath>$(_FSharpCompilerPath)/fsi.exe</DotnetFsiCompilerPath>
+    <DotnetFsiCompilerPath>$(MSBuildThisFileDirectory)artifacts\bin\fsi\$(Configuration)\netcoreapp2.1\fsi.exe</DotnetFsiCompilerPath>
   </PropertyGroup>
 
   <!-- SDK targets override -->
   <PropertyGroup>
-    <FSharpTargetsPath>$(_FSharpCompilerPath)/Microsoft.FSharp.Targets</FSharpTargetsPath>
-    <FSharpPropsShim>$(_FSharpCompilerPath)/Microsoft.FSharp.NetSdk.props</FSharpPropsShim>
-    <FSharpTargetsShim>$(_FSharpCompilerPath)/Microsoft.FSharp.NetSdk.targets</FSharpTargetsShim>
-    <FSharpOverridesTargetsShim>$(_FSharpCompilerPath)/Microsoft.FSharp.Overrides.NetSdk.targets</FSharpOverridesTargetsShim>
-  </PropertyGroup>
+    <_FSharpBuildTargetFramework Condition="'$(FSharpTestCompilerVersion)' == 'net40'">net472</_FSharpBuildTargetFramework>
+    <_FSharpBuildTargetFramework Condition="'$(FSharpTestCompilerVersion)' == 'coreclr'">netstandard2.0</_FSharpBuildTargetFramework>
+    <_FSharpBuildBinPath>$(MSBuildThisFileDirectory)artifacts\bin\FSharp.Build\$(Configuration)\$(_FSharpBuildTargetFramework)</_FSharpBuildBinPath>
 
+    <FSharpBuildAssemblyFile>$(_FSharpBuildBinPath)\FSharp.Build.dll</FSharpBuildAssemblyFile>
 
-  <!-- We are running under netcore so even though we will use the fsc compiler we can't use the desktop version of the fsharp.build tasks -->
-  <PropertyGroup>
-    <FSharpBuildAssemblyFile Condition = " '$(DOTNET_HOST_PATH)' != '' ">$(MSBuildThisFileDirectory)$(Configuration)\coreclr\bin\FSharp.Build.dll</FSharpBuildAssemblyFile>
-    <FSharpBuildAssemblyFile Condition = " '$(DOTNET_HOST_PATH)' == '' ">$(MSBuildThisFileDirectory)$(Configuration)\net40\bin\FSharp.Build.dll</FSharpBuildAssemblyFile>
+    <FSharpTargetsPath>$(_FSharpBuildBinPath)/Microsoft.FSharp.Targets</FSharpTargetsPath>
+    <FSharpPropsShim>$(_FSharpBuildBinPath)/Microsoft.FSharp.NetSdk.props</FSharpPropsShim>
+    <FSharpTargetsShim>$(_FSharpBuildBinPath)/Microsoft.FSharp.NetSdk.targets</FSharpTargetsShim>
+    <FSharpOverridesTargetsShim>$(_FSharpBuildBinPath)/Microsoft.FSharp.Overrides.NetSdk.targets</FSharpOverridesTargetsShim>
   </PropertyGroup>
-</Project>
\ No newline at end of file
+
+</Project>
diff --git a/Makefile b/Makefile
index 35db8f37561..dfb567b394b 100644
--- a/Makefile
+++ b/Makefile
@@ -1,28 +1,29 @@
 Configuration ?= release
 DotNetVersion = `cat DotnetCLIToolsVersion.txt`
-DotNetExe = "$(CURDIR)/Tools/dotnet20/dotnet"
+DotNetToolPath = $(CURDIR)/artifacts/toolset/dotnet
+DotNetExe = "$(DotNetToolPath)/dotnet"
 
 all: proto restore build test
 
 tools:
-	$(CURDIR)/scripts/dotnet-install.sh --version $(DotNetVersion) --install-dir $(CURDIR)/Tools/dotnet20
+	$(CURDIR)/scripts/dotnet-install.sh --version $(DotNetVersion) --install-dir "$(DotNetToolPath)"
 
 proto: tools
 	$(DotNetExe) build-server shutdown
 	$(DotNetExe) restore src/buildtools/buildtools.proj
 	$(DotNetExe) restore src/fsharp/FSharp.Build/FSharp.Build.fsproj
-	$(DotNetExe) restore src/fsharp/Fsc/Fsc.fsproj
+	$(DotNetExe) restore src/fsharp/fsc/fsc.fsproj
 	$(DotNetExe) build src/buildtools/buildtools.proj -c Proto
 	$(DotNetExe) build src/fsharp/FSharp.Build/FSharp.Build.fsproj -f netstandard2.0 -c Proto
-	$(DotNetExe) build src/fsharp/Fsc/Fsc.fsproj -f netcoreapp2.1 -c Proto
+	$(DotNetExe) build src/fsharp/fsc/fsc.fsproj -f netcoreapp2.1 -c Proto
 
 restore:
 	$(DotNetExe) restore src/fsharp/FSharp.Core/FSharp.Core.fsproj
 	$(DotNetExe) restore src/fsharp/FSharp.Build/FSharp.Build.fsproj
 	$(DotNetExe) restore src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
-	$(DotNetExe) restore src/fsharp/Fsc/Fsc.fsproj
+	$(DotNetExe) restore src/fsharp/fsc/fsc.fsproj
 	$(DotNetExe) restore src/fsharp/FSharp.Compiler.Interactive.Settings/FSharp.Compiler.Interactive.Settings.fsproj
-	$(DotNetExe) restore src/fsharp/fsi/Fsi.fsproj
+	$(DotNetExe) restore src/fsharp/fsi/fsi.fsproj
 	$(DotNetExe) restore tests/FSharp.Core.UnitTests/FSharp.Core.UnitTests.fsproj
 	$(DotNetExe) restore tests/FSharp.Build.UnitTests/FSharp.Build.UnitTests.fsproj
 
@@ -31,17 +32,15 @@ build: proto restore
 	$(DotNetExe) build -c $(Configuration) -f netstandard1.6 src/fsharp/FSharp.Core/FSharp.Core.fsproj
 	$(DotNetExe) build -c $(Configuration) -f netstandard2.0 src/fsharp/FSharp.Build/FSharp.Build.fsproj
 	$(DotNetExe) build -c $(Configuration) -f netstandard1.6 src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
-	$(DotNetExe) build -c $(Configuration) -f netcoreapp2.1 src/fsharp/Fsc/Fsc.fsproj
+	$(DotNetExe) build -c $(Configuration) -f netcoreapp2.1 src/fsharp/fsc/fsc.fsproj
 	$(DotNetExe) build -c $(Configuration) -f netstandard1.6 src/fsharp/FSharp.Compiler.Interactive.Settings/FSharp.Compiler.Interactive.Settings.fsproj
-	$(DotNetExe) build -c $(Configuration) -f netcoreapp2.0 src/fsharp/fsi/Fsi.fsproj
+	$(DotNetExe) build -c $(Configuration) -f netcoreapp2.1 src/fsharp/fsi/fsi.fsproj
 	$(DotNetExe) build -c $(Configuration) -f netcoreapp2.0 tests/FSharp.Core.UnitTests/FSharp.Core.UnitTests.fsproj
 	$(DotNetExe) build -c $(Configuration) -f netcoreapp2.0 tests/FSharp.Build.UnitTests/FSharp.Build.UnitTests.fsproj
 
 test: build
-	$(DotNetExe) test -f netcoreapp2.0 -c $(Configuration) --no-restore --no-build tests/FSharp.Core.UnitTests/FSharp.Core.UnitTests.fsproj -l "trx;LogFileName=$(CURDIR)/tests/TestResults/FSharp.Core.UnitTests.coreclr.trx"
-	$(DotNetExe) test -f netcoreapp2.0 -c $(Configuration) --no-restore --no-build tests/FSharp.Build.UnitTests/FSharp.Build.UnitTests.fsproj -l "trx;LogFileName=$(CURDIR)/tests/TestResults/FSharp.Build.UnitTests.coreclr.trx"
+	$(DotNetExe) test -f netcoreapp2.1 -c $(Configuration) --no-restore --no-build tests/FSharp.Core.UnitTests/FSharp.Core.UnitTests.fsproj -l "trx;LogFileName=$(CURDIR)/tests/TestResults/FSharp.Core.UnitTests.coreclr.trx"
+	$(DotNetExe) test -f netcoreapp2.1 -c $(Configuration) --no-restore --no-build tests/FSharp.Build.UnitTests/FSharp.Build.UnitTests.fsproj -l "trx;LogFileName=$(CURDIR)/tests/TestResults/FSharp.Build.UnitTests.coreclr.trx"
 
 clean:
-	rm -rf $(CURDIR)/Proto
-	rm -rf $(CURDIR)/debug
-	rm -rf $(CURDIR)/release
+	rm -rf $(CURDIR)/artifacts
diff --git a/PublishToBlob.proj b/PublishToBlob.proj
index 5a81152646e..21e8ec6eb6f 100644
--- a/PublishToBlob.proj
+++ b/PublishToBlob.proj
@@ -17,7 +17,7 @@
 
   <ItemGroup>
     <!-- the string '-rtm-' is important, because that's the package with a per-build unique version number -->
-    <NuGetPackages Include="$(MSBuildThisFileDirectory)$(Configuration)\artifacts\Microsoft.FSharp.Compiler.*-rtm-*.nupkg" />
+    <NuGetPackages Include="$(MSBuildThisFileDirectory)artifacts\packages\$(Configuration)\Microsoft.FSharp.Compiler.*-rtm-*.nupkg" />
   </ItemGroup>
 
   <PropertyGroup>
diff --git a/artifacts/.gitignore b/artifacts/.gitignore
deleted file mode 100644
index 72e8ffc0db8..00000000000
--- a/artifacts/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-*
diff --git a/build-nuget-packages.proj b/build-nuget-packages.proj
index 37a64ed6535..8b279bd8a19 100644
--- a/build-nuget-packages.proj
+++ b/build-nuget-packages.proj
@@ -3,6 +3,7 @@
 
   <ItemGroup>
     <PackageProjects Include="src\fsharp\FSharp.Compiler.nuget\Microsoft.FSharp.Compiler.csproj" Condition="'$(BUILD_CORECLR)'=='1'" />
+    <PackageProjects Include="src\fsharp\FSharp.Compiler.nuget\Microsoft.FSharp.Compiler.Prerelease.csproj" Condition="'$(BUILD_CORECLR)'=='1'" />
     <PackageProjects Include="src\fsharp\FSharp.Core\FSharp.Core.fsproj" Condition="'$(BUILD_NUGET)'=='1'" />
   </ItemGroup>
 
diff --git a/build.cmd b/build.cmd
index cb29c798639..84b8390cfb7 100644
--- a/build.cmd
+++ b/build.cmd
@@ -1,6 +1,5 @@
 rem Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.
 @if "%_echo%"=="" echo off
-
 setlocal enableDelayedExpansion
 
 :ARGUMENTS_VALIDATION
@@ -63,9 +62,10 @@ set BUILD_CORECLR=0
 set BUILD_FROMSOURCE=0
 set BUILD_VS=0
 set BUILD_FCS=0
-set BUILD_CONFIG=release
+set BUILD_CONFIG=Release
 set BUILD_DIAG=
 set BUILD_PUBLICSIGN=0
+set BUILD_FSHARP_PROJ=1
 
 set TEST_NET40_COMPILERUNIT_SUITE=0
 set TEST_NET40_COREUNIT_SUITE=0
@@ -162,7 +162,6 @@ if /i "%ARG%" == "net40" (
 
 if /i "%ARG%" == "coreclr" (
     set _autoselect=0
-    set BUILD_PROTO_WITH_CORECLR_LKG=1
     set BUILD_CORECLR=1
     set BUILD_FROMSOURCE=1
 )
@@ -228,8 +227,8 @@ if /i "%ARG%" == "microbuild" (
     set CI=1
 
     REM redirecting TEMP directories
-    set TEMP=%~dp0%BUILD_CONFIG%\TEMP
-    set TMP=%~dp0%BUILD_CONFIG%\TEMP
+    set TEMP=%~dp0artifacts\tmp
+    set TMP=%~dp0artifacts\tmp
 )
 
 if /i "%ARG%" == "nuget" (
@@ -237,7 +236,7 @@ if /i "%ARG%" == "nuget" (
 
     set BUILD_PROTO=1
     set BUILD_NET40_FSHARP_CORE=1
-    set BUILD_PROTO_WITH_CORECLR_LKG=1
+    set BUILD_NET40=1
     set BUILD_CORECLR=1
     set BUILD_NUGET=1
 )
@@ -319,11 +318,11 @@ if /i "%ARG%" == "diag" (
 )
 
 if /i "%ARG%" == "debug" (
-    set BUILD_CONFIG=debug
+    set BUILD_CONFIG=Debug
 )
 
 if /i "%ARG%" == "release" (
-    set BUILD_CONFIG=release
+    set BUILD_CONFIG=Release
 )
 
 if /i "%ARG%" == "test-sign" (
@@ -464,10 +463,15 @@ if /i "%TEST_NET40_FSHARP_SUITE" == "1" (
 )
 
 rem Decide if Proto need building
-if NOT EXIST Proto\net40\bin\fsc.exe (
+if NOT EXIST "%~dp0artifacts\bin\fsc\Proto\net472\fsc.exe" (
   set BUILD_PROTO=1
 )
 
+rem decide if FSharp.Proj needs building
+if "%BUILD_NET40%"=="0" if "%BUILD_NET40_FSHARP_CORE%"=="0" if "%BUILD_CORECLR%"=="0" if "%BUILD_VS%"=="0" if "%BUILD_FCS%"=="0" if "%TEST_NET40_COMPILERUNIT_SUITE%"=="0" if "%TEST_NET40_COREUNIT_SUITE%"=="0" if "%TEST_NET40_FSHARP_SUITE%"=="0" if "%TEST_NET40_FSHARPQA_SUITE%"=="0" if "%TEST_CORECLR_COREUNIT_SUITE%"=="0" if "%TEST_CORECLR_FSHARP_SUITE%"=="0" if "%TEST_VS_IDEUNIT_SUITE%"=="0" if "%TEST_FCS%"=="0" if "%TEST_END_2_END%"=="0" if "%COPY_FSCOMP_RESOURCE_FOR_BUILD_FROM_SOURCES%"=="0" (
+   set BUILD_FSHARP_PROJ=0
+)
+
 rem
 rem This stops the dotnet cli from hunting around and 
 rem finding the highest possible dotnet sdk version to use.
@@ -483,7 +487,6 @@ echo BUILD_PROTO_WITH_CORECLR_LKG=%BUILD_PROTO_WITH_CORECLR_LKG%
 echo BUILD_NET40=%BUILD_NET40%
 echo BUILD_NET40_FSHARP_CORE=%BUILD_NET40_FSHARP_CORE%
 echo BUILD_CORECLR=%BUILD_CORECLR%
-echo BUILD_FROMSOURCE=%BUILD_FROMSOURCE%
 echo BUILD_VS=%BUILD_VS%
 echo BUILD_FCS=%BUILD_FCS%
 echo BUILD_SETUP=%BUILD_SETUP%
@@ -491,6 +494,8 @@ echo BUILD_NUGET=%BUILD_NUGET%
 echo BUILD_CONFIG=%BUILD_CONFIG%
 echo BUILD_PUBLICSIGN=%BUILD_PUBLICSIGN%
 echo BUILD_MICROBUILD=%BUILD_MICROBUILD%
+echo BUILD_FROMSOURCE=%BUILD_FROMSOURCE%
+echo BUILD_FSHARP_PROJ=%BUILD_FSHARP_PROJ%
 echo.
 echo PB_SKIPTESTS=%PB_SKIPTESTS%
 echo PB_RESTORESOURCE=%PB_RESTORESOURCE%
@@ -610,13 +615,13 @@ echo ---------------- Done with prepare, starting package restore --------------
 
 :: Restore the Tools directory
 call "%~dp0init-tools.cmd"
-set _dotnetexe=%~dp0Tools\dotnet20\dotnet.exe
-set path=%~dp0Tools\dotnet20\;%path%
+set _dotnetexe=%~dp0artifacts\toolset\dotnet\dotnet.exe
+set path=%~dp0artifacts\toolset\dotnet;%path%
 
 if not "%PB_PackageVersionPropsUrl%" == "" (
     echo ----------- do dependency uptake check -----------
 
-    set dependencyUptakeDir=%~dp0Tools\dependencyUptake
+    set dependencyUptakeDir=%~dp0artifacts\dependencyUptake
     if not exist "!dependencyUptakeDir!" mkdir "!dependencyUptakeDir!"
 
     :: download package version overrides
@@ -643,31 +648,31 @@ if "%BUILD_PROTO_WITH_CORECLR_LKG%" == "1" (
 )
 
 echo ---------------- Done with package restore, starting proto ------------------------
-set logdir=%~dp0%BUILD_CONFIG%\logs
+set logdir=%~dp0artifacts\log\%BUILD_CONFIG%
 if not exist "!logdir!" mkdir "!logdir!"
 
 rem Build Proto
 if "%BUILD_PROTO%" == "1" (
-    rmdir /s /q Proto
+    rmdir /s /q artifacts/bin/fsc/Proto
 
-    echo %_msbuildexe% proto.proj /t:Restore /bl:%~dp0Proto\proto.proj.restore.binlog
-         %_msbuildexe% proto.proj /t:Restore /bl:%~dp0Proto\proto.proj.restore.binlog
+    echo %_msbuildexe% proto.proj /t:Restore /bl:%~dp0artifacts\log\Proto\proto.proj.restore.binlog
+         %_msbuildexe% proto.proj /t:Restore /bl:%~dp0artifacts\log\Proto\proto.proj.restore.binlog
     @if ERRORLEVEL 1 echo Error restoring proto failed && goto :failure
 
-    echo %_msbuildexe% proto.proj /t:Build /bl:%~dp0Proto\proto.proj.build.binlog
-         %_msbuildexe% proto.proj /t:Build /bl:%~dp0Proto\proto.proj.build.binlog
+    echo %_msbuildexe% proto.proj /t:Build /bl:%~dp0artifacts\log\Proto\proto.proj.build.binlog
+         %_msbuildexe% proto.proj /t:Build /bl:%~dp0artifacts\log\Proto\proto.proj.build.binlog
     @if ERRORLEVEL 1 echo Error building proto failed && goto :failure
 )
 
 echo ---------------- Done with SDK restore, starting build ------------------------
 
-if "%BUILD_PHASE%" == "1" (
+if "%BUILD_PHASE%" == "1" if "%BUILD_FSHARP_PROJ%" == "1" (
 
-    echo %_msbuildexe% fsharp.proj /t:Restore /p:Configuration=%BUILD_CONFIG% /bl:%~dp0%BUILD_CONFIG%\fsharp.proj.restore.binlog
-         %_msbuildexe% fsharp.proj /t:Restore /p:Configuration=%BUILD_CONFIG% /bl:%~dp0%BUILD_CONFIG%\fsharp.proj.restore.binlog
+    echo %_dotnetexe% restore fsharp.proj /p:Configuration=%BUILD_CONFIG% /bl:!logdir!\fsharp.proj.restore.binlog
+         %_dotnetexe% restore fsharp.proj /p:Configuration=%BUILD_CONFIG% /bl:!logdir!\fsharp.proj.restore.binlog
 
-    echo %_msbuildexe% fsharp.proj /t:Build /p:Configuration=%BUILD_CONFIG% /p:BUILD_PUBLICSIGN=%BUILD_PUBLICSIGN% /bl:%~dp0%BUILD_CONFIG%\fsharp.proj.build.binlog
-         %_msbuildexe% fsharp.proj /t:Build /p:Configuration=%BUILD_CONFIG% /p:BUILD_PUBLICSIGN=%BUILD_PUBLICSIGN% /bl:%~dp0%BUILD_CONFIG%\fsharp.proj.build.binlog
+    echo %_msbuildexe% fsharp.proj /t:Build /p:Configuration=%BUILD_CONFIG% /p:BUILD_PUBLICSIGN=%BUILD_PUBLICSIGN% /bl:!logdir!\fsharp.proj.build.binlog
+         %_msbuildexe% fsharp.proj /t:Build /p:Configuration=%BUILD_CONFIG% /p:BUILD_PUBLICSIGN=%BUILD_PUBLICSIGN% /bl:!logdir!\fsharp.proj.build.binlog
 
    @if ERRORLEVEL 1 echo Error build failed && goto :failure
 )
@@ -677,8 +682,8 @@ set asmvercheckpath=%~dp0tests\fsharpqa\testenv\src\AssemblyVersionCheck
 
 if "%BUILD_NET40%" == "1" (
   echo #r @"%USERPROFILE%\.nuget\packages\Newtonsoft.Json\9.0.1\lib\net45\Newtonsoft.Json.dll">%asmvercheckpath%\assemblies.fsx
-  echo "%~dp0%BUILD_CONFIG%\net40\bin\fsi.exe" "%asmvercheckpath%\AssemblyVersionCheck.fsx" -- "%~dp0build\config\AssemblySignToolData.json" "%~dp0%BUILD_CONFIG%"
-       "%~dp0%BUILD_CONFIG%\net40\bin\fsi.exe" "%asmvercheckpath%\AssemblyVersionCheck.fsx" -- "%~dp0build\config\AssemblySignToolData.json" "%~dp0%BUILD_CONFIG%"
+  echo "%~dp0artifacts\bin\fsi\%BUILD_CONFIG%\net472\fsi.exe" "%asmvercheckpath%\AssemblyVersionCheck.fsx" -- "%~dp0build\config\AssemblySignToolData.json" "%~dp0artifacts"
+       "%~dp0artifacts\bin\fsi\%BUILD_CONFIG%\net472\fsi.exe" "%asmvercheckpath%\AssemblyVersionCheck.fsx" -- "%~dp0build\config\AssemblySignToolData.json" "%~dp0artifacts"
   if ERRORLEVEL 1 echo Error verifying assembly versions and commit hashes. && goto :failure
 )
 
@@ -688,56 +693,46 @@ if not "%SIGN_TYPE%" == "" (
     echo %_msbuildexe% build\projects\Signing.proj /t:Restore
          %_msbuildexe% build\projects\Signing.proj /t:Restore
 
-    echo %_msbuildexe% build\projects\Signing.proj /t:DoSigning /p:SignType=%SIGN_TYPE% /p:Configuration=%BUILD_CONFIG% /p:ConfigFile=%~dp0build\config\AssemblySignToolData.json
-         %_msbuildexe% build\projects\Signing.proj /t:DoSigning /p:SignType=%SIGN_TYPE% /p:Configuration=%BUILD_CONFIG% /p:ConfigFile=%~dp0build\config\AssemblySignToolData.json
+    echo %_msbuildexe% build\projects\Signing.proj /t:DoSigning /p:SignType=%SIGN_TYPE% /p:Configuration=%BUILD_CONFIG% /p:BinaryBasePath=%~dp0artifacts /p:ConfigFile=%~dp0build\config\AssemblySignToolData.json
+         %_msbuildexe% build\projects\Signing.proj /t:DoSigning /p:SignType=%SIGN_TYPE% /p:Configuration=%BUILD_CONFIG% /p:BinaryBasePath=%~dp0artifacts /p:ConfigFile=%~dp0build\config\AssemblySignToolData.json
 
     if ERRORLEVEL 1 echo Error running sign tool && goto :failure
 )
 
 echo ---------------- Done with assembly signing, start package creation ---------------
 
-echo %_msbuildexe% %msbuildflags% build-nuget-packages.proj /p:Configuration=%BUILD_CONFIG% /t:Pack /bl:%~dp0%BUILD_CONFIG%\logs\msbuild.build-nuget-packages.build.%BUILD_CONFIG%.binlog
-     %_msbuildexe% %msbuildflags% build-nuget-packages.proj /p:Configuration=%BUILD_CONFIG% /t:Pack /bl:%~dp0%BUILD_CONFIG%\logs\msbuild.build-nuget-packages.build.%BUILD_CONFIG%.binlog
+echo %_msbuildexe% %msbuildflags% build-nuget-packages.proj /p:Configuration=%BUILD_CONFIG% /t:Pack /bl:!logdir!\msbuild.build-nuget-packages.build.%BUILD_CONFIG%.binlog
+     %_msbuildexe% %msbuildflags% build-nuget-packages.proj /p:Configuration=%BUILD_CONFIG% /t:Pack /bl:!logdir!\msbuild.build-nuget-packages.build.%BUILD_CONFIG%.binlog
 if ERRORLEVEL 1 echo Error building NuGet packages && goto :failure
 
 if not "%SIGN_TYPE%" == "" (
-    echo %_msbuildexe% build\projects\Signing.proj /t:DoSigning /p:SignType=%SIGN_TYPE% /p:Configuration=%BUILD_CONFIG% /p:ConfigFile=%~dp0build\config\PackageSignToolData.json
-         %_msbuildexe% build\projects\Signing.proj /t:DoSigning /p:SignType=%SIGN_TYPE% /p:Configuration=%BUILD_CONFIG% /p:ConfigFile=%~dp0build\config\PackageSignToolData.json
+    echo %_msbuildexe% build\projects\Signing.proj /t:DoSigning /p:SignType=%SIGN_TYPE% /p:Configuration=%BUILD_CONFIG% /p:BinaryBasepath=%~dp0artifacts\packages\%BUILD_CONFIG% /p:ConfigFile=%~dp0build\config\PackageSignToolData.json
+         %_msbuildexe% build\projects\Signing.proj /t:DoSigning /p:SignType=%SIGN_TYPE% /p:Configuration=%BUILD_CONFIG% /p:BinaryBasepath=%~dp0artifacts\packages\%BUILD_CONFIG% /p:ConfigFile=%~dp0build\config\PackageSignToolData.json
     if ERRORLEVEL 1 echo Error running sign tool && goto :failure
 )
 
 if "%BUILD_SETUP%" == "1" (
-    echo %_msbuildexe% %msbuildflags% setup\build-insertion.proj /p:Configuration=%BUILD_CONFIG%  /bl:%~dp0%BUILD_CONFIG%\logs\msbuild.build-insertion.build.%BUILD_CONFIG%.binlog
-         %_msbuildexe% %msbuildflags% setup\build-insertion.proj /p:Configuration=%BUILD_CONFIG%  /bl:%~dp0%BUILD_CONFIG%\logs\msbuild.build-insertion.build.%BUILD_CONFIG%.binlog
+    echo %_msbuildexe% %msbuildflags% setup\build-insertion.proj /p:Configuration=%BUILD_CONFIG%  /bl:!logdir!\msbuild.build-insertion.build.%BUILD_CONFIG%.binlog
+         %_msbuildexe% %msbuildflags% setup\build-insertion.proj /p:Configuration=%BUILD_CONFIG%  /bl:!logdir!\msbuild.build-insertion.build.%BUILD_CONFIG%.binlog
     if ERRORLEVEL 1 echo Error building insertion packages && goto :failure
 )
 
 if not "%SIGN_TYPE%" == "" (
-    echo %_msbuildexe% build\projects\Signing.proj /t:DoSigning /p:SignType=%SIGN_TYPE% /p:Configuration=%BUILD_CONFIG% /p:ConfigFile=%~dp0build\config\InsertionSignToolData.json
-         %_msbuildexe% build\projects\Signing.proj /t:DoSigning /p:SignType=%SIGN_TYPE% /p:Configuration=%BUILD_CONFIG% /p:ConfigFile=%~dp0build\config\InsertionSignToolData.json
+    echo %_msbuildexe% build\projects\Signing.proj /t:DoSigning /p:SignType=%SIGN_TYPE% /p:Configuration=%BUILD_CONFIG% /p:BinaryBasepath=%~dp0artifacts\VSSetup\%BUILD_CONFIG%\Insertion /p:ConfigFile=%~dp0build\config\InsertionSignToolData.json
+         %_msbuildexe% build\projects\Signing.proj /t:DoSigning /p:SignType=%SIGN_TYPE% /p:Configuration=%BUILD_CONFIG% /p:BinaryBasePath=%~dp0artifacts\VSSetup\%BUILD_CONFIG%\Insertion /p:ConfigFile=%~dp0build\config\InsertionSignToolData.json
     if ERRORLEVEL 1 echo Error running sign tool && goto :failure
 )
 
 echo ---------------- Done with signing, building insertion files ---------------
 
 if "%BUILD_SETUP%" == "1" (
-    echo %_msbuildexe% %msbuildflags% setup\Swix\Microsoft.FSharp.vsmanproj /p:Configuration=%BUILD_CONFIG% /bl:%~dp0%BUILD_CONFIG%\logs\msbuild.setup-swix.build.%BUILD_CONFIG%.binlog
-         %_msbuildexe% %msbuildflags% setup\Swix\Microsoft.FSharp.vsmanproj /p:Configuration=%BUILD_CONFIG% /bl:%~dp0%BUILD_CONFIG%\logs\msbuild.setup-swix.build.%BUILD_CONFIG%.binlog
+    echo %_msbuildexe% %msbuildflags% setup\Swix\Microsoft.FSharp.vsmanproj /p:Configuration=%BUILD_CONFIG% /bl:!logdir!\msbuild.setup-swix.build.%BUILD_CONFIG%.binlog
+         %_msbuildexe% %msbuildflags% setup\Swix\Microsoft.FSharp.vsmanproj /p:Configuration=%BUILD_CONFIG% /bl:!logdir!\msbuild.setup-swix.build.%BUILD_CONFIG%.binlog
     if ERRORLEVEL 1 echo Error building .vsmanproj && goto :failure
 )
 
 echo ---------------- Done building insertion files, starting pack/update/prepare ---------------
 
-if "%BUILD_NET40_FSHARP_CORE%" == "1" (
-  echo ----------------  start update.cmd ---------------
-  call src\update.cmd %BUILD_CONFIG% -ngen
-)
-
-if "%COPY_FSCOMP_RESOURCE_FOR_BUILD_FROM_SOURCES%" == "1" (
-  echo ----------------  copy fscomp resource for build from sources ---------------
-  copy /y src\fsharp\FSharp.Compiler.Private\obj\%BUILD_CONFIG%\net40\FSComp.* src\buildfromsource\FSharp.Compiler.Private
-)
-
 set X86_PROGRAMFILES=%ProgramFiles%
 if "%OSARCH%"=="AMD64" set X86_PROGRAMFILES=%ProgramFiles(x86)%
 
@@ -783,21 +778,19 @@ if not exist "%link_exe%" (
 
 if /I not "%single_threaded%" == "true" (set PARALLEL_ARG=-procs:%NUMBER_OF_PROCESSORS%) else set PARALLEL_ARG=-procs:0
 
-set FSCBINPATH=%~dp0%BUILD_CONFIG%\net40\bin
-set RESULTSDIR=%~dp0tests\TestResults
-if not exist "%RESULTSDIR%" (mkdir "%RESULTSDIR%")
+set FSCBINPATH=%~dp0artifacts\bin\fsc\%BUILD_CONFIG%\net472
 
 ECHO FSCBINPATH=%FSCBINPATH%
-ECHO RESULTSDIR=%RESULTSDIR%
 ECHO link_exe=%link_exe%
 
 REM ---------------- test-net40-fsharp  -----------------------
 
+set TESTLOGDIR=%~dp0artifacts\TestResults\%BUILD_CONFIG%
 if "%TEST_NET40_FSHARP_SUITE%" == "1" (
 
-    set LOGFILE=%~dp0tests\TestResults\FSharp.Tests.FSharpSuite.net40.trx
-    echo "%_dotnetexe%" test "%~dp0tests\fsharp\FSharp.Tests.FSharpSuite.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!" -o "%~dp0%BUILD_CONFIG%\net40\bin"
-         "%_dotnetexe%" test "%~dp0tests\fsharp\FSharp.Tests.FSharpSuite.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!" -o "%~dp0%BUILD_CONFIG%\net40\bin"
+    set LOGFILE=%TESTLOGDIR%\FSharp.Tests.FSharpSuite_net472.trx
+    echo "%_dotnetexe%" test "%~dp0tests\fsharp\FSharp.Tests.FSharpSuite.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
+         "%_dotnetexe%" test "%~dp0tests\fsharp\FSharp.Tests.FSharpSuite.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
 
     if errorlevel 1 (
         echo --------------------------------------------------------------
@@ -805,15 +798,22 @@ if "%TEST_NET40_FSHARP_SUITE%" == "1" (
         echo --------------------------------------------------------------
         goto :failure
     )
+
+    if not exist "!LOGFILE!" (
+        echo --------------------------------------------------------
+        echo Test results file !LOGFILE! not found, ensure tests ran.
+        echo --------------------------------------------------------
+        goto :failure
+    )
 )
 
 REM ---------------- test-fcs  -----------------------
 
 if "%TEST_FCS%" == "1" (
 
-    set LOGFILE=%~dp0tests\TestResults\FSharp.Compiler.Service.Tests.net40.trx
-    echo "%_dotnetexe%" test "%~dp0fcs\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
-         "%_dotnetexe%" test "%~dp0fcs\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
+    set LOGFILE=%TESTLOGDIR%\FSharp.Compiler.Service.Tests_net46.trx
+    echo "%_dotnetexe%" test "%~dp0fcs\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net46 -l "trx;LogFileName=!LOGFILE!"
+         "%_dotnetexe%" test "%~dp0fcs\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net46 -l "trx;LogFileName=!LOGFILE!"
 
     if errorlevel 1 (
         echo --------------------------------------------------------------
@@ -822,7 +822,14 @@ if "%TEST_FCS%" == "1" (
         goto :failure
     )
 
-    set LOGFILE=%~dp0tests\TestResults\FSharp.Compiler.Service.Tests.coreclr.trx
+    if not exist "!LOGFILE!" (
+        echo --------------------------------------------------------
+        echo Test results file !LOGFILE! not found, ensure tests ran.
+        echo --------------------------------------------------------
+        goto :failure
+    )
+
+    set LOGFILE=%TESTLOGDIR%\FSharp.Compiler.Service.Tests_netcoreapp2.0.trx
     echo "%_dotnetexe%" test "%~dp0fcs\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f netcoreapp2.0 -l "trx;LogFileName=!LOGFILE!"
          "%_dotnetexe%" test "%~dp0fcs\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f netcoreapp2.0 -l "trx;LogFileName=!LOGFILE!"
 
@@ -832,6 +839,13 @@ if "%TEST_FCS%" == "1" (
         echo --------------------------------------------------------------
         goto :failure
     )
+
+    if not exist "!LOGFILE!" (
+        echo --------------------------------------------------------
+        echo Test results file !LOGFILE! not found, ensure tests ran.
+        echo --------------------------------------------------------
+        goto :failure
+    )
 )
 
 REM ---------------- end2end  -----------------------
@@ -867,6 +881,7 @@ if "%TEST_NET40_FSHARPQA_SUITE%" == "1" (
     set perlexe=%USERPROFILE%\.nuget\packages\StrawberryPerl64\5.22.2.1\Tools\perl\bin\perl.exe
     if not exist !perlexe! (echo Error: perl was not downloaded from check the packages directory: !perlexe! && goto :failure )
 
+    set RESULTSDIR=%~dp0artifacts\TestResults\%BUILD_CONFIG%
     set OUTPUTFILE=test-net40-fsharpqa-results.log
     set ERRORFILE=test-net40-fsharpqa-errors.log
     set FAILENV=test-net40-fsharpqa-errors
@@ -877,9 +892,10 @@ if "%TEST_NET40_FSHARPQA_SUITE%" == "1" (
 
     popd
     if ERRORLEVEL 1 (
-        type "%RESULTSDIR%\!OUTPUTFILE!"
         echo -----------------------------------------------------------------
-        type "%RESULTSDIR%\!ERRORFILE!"
+        type "!RESULTSDIR!\!OUTPUTFILE!"
+        echo -----------------------------------------------------------------
+        type "!RESULTSDIR!\!ERRORFILE!"
         echo -----------------------------------------------------------------
         echo Error: Running tests net40-fsharpqa failed, see logs above -- FAILED
         echo -----------------------------------------------------------------
@@ -891,7 +907,7 @@ REM ---------------- net40-compilerunit  -----------------------
 
 if "%TEST_NET40_COMPILERUNIT_SUITE%" == "1" (
 
-    set LOGFILE=%~dp0tests\TestResults\FSharp.Compiler.UnitTests.net40.trx
+    set LOGFILE=%TESTLOGDIR%\FSharp.Compiler.UnitTests_net472.trx
     echo "%_dotnetexe%" test "%~dp0tests\FSharp.Compiler.UnitTests\FSharp.Compiler.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
          "%_dotnetexe%" test "%~dp0tests\FSharp.Compiler.UnitTests\FSharp.Compiler.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
 
@@ -902,7 +918,14 @@ if "%TEST_NET40_COMPILERUNIT_SUITE%" == "1" (
         goto :failure
     )
 
-    set LOGFILE=%~dp0tests\TestResults\FSharp.Build.UnitTests.net40.trx
+    if not exist "!LOGFILE!" (
+        echo --------------------------------------------------------
+        echo Test results file !LOGFILE! not found, ensure tests ran.
+        echo --------------------------------------------------------
+        goto :failure
+    )
+
+    set LOGFILE=%TESTLOGDIR%\FSharp.Build.UnitTests_net472.trx
     echo "%_dotnetexe%" test "%~dp0tests\FSharp.Build.UnitTests\FSharp.Build.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
          "%_dotnetexe%" test "%~dp0tests\FSharp.Build.UnitTests\FSharp.Build.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
 
@@ -912,13 +935,20 @@ if "%TEST_NET40_COMPILERUNIT_SUITE%" == "1" (
         echo -----------------------------------------------------------------
         goto :failure
     )
+
+    if not exist "!LOGFILE!" (
+        echo --------------------------------------------------------
+        echo Test results file !LOGFILE! not found, ensure tests ran.
+        echo --------------------------------------------------------
+        goto :failure
+    )
 )
 
 REM ---------------- net40-coreunit  -----------------------
 
 if "%TEST_NET40_COREUNIT_SUITE%" == "1" (
 
-    set LOGFILE=%~dp0tests\TestResults\FSharp.Core.UnitTests.net40.trx
+    set LOGFILE=%TESTLOGDIR%\FSharp.Core.UnitTests_net472.trx
     echo "%_dotnetexe%" test "%~dp0tests\FSharp.Core.UnitTests\FSharp.Core.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
          "%_dotnetexe%" test "%~dp0tests\FSharp.Core.UnitTests\FSharp.Core.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
 
@@ -928,13 +958,20 @@ if "%TEST_NET40_COREUNIT_SUITE%" == "1" (
         echo -----------------------------------------------------------------
         goto :failure
     )
+
+    if not exist "!LOGFILE!" (
+        echo --------------------------------------------------------
+        echo Test results file !LOGFILE! not found, ensure tests ran.
+        echo --------------------------------------------------------
+        goto :failure
+    )
 )
 
 REM  ---------------- coreclr-coreunit  -----------------------
 
 if "%TEST_CORECLR_COREUNIT_SUITE%" == "1" (
 
-    set LOGFILE=%~dp0tests\TestResults\FSharp.Build.UnitTests.coreclr.trx
+    set LOGFILE=%TESTLOGDIR%\FSharp.Build.UnitTests_netcoreapp2.0.trx
     echo "%_dotnetexe%" test "%~dp0tests\FSharp.Build.UnitTests\FSharp.Build.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f netcoreapp2.0 -l "trx;LogFileName=!LOGFILE!"
          "%_dotnetexe%" test "%~dp0tests\FSharp.Build.UnitTests\FSharp.Build.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f netcoreapp2.0 -l "trx;LogFileName=!LOGFILE!"
 
@@ -945,7 +982,14 @@ if "%TEST_CORECLR_COREUNIT_SUITE%" == "1" (
         goto :failure
     )
 
-    set LOGFILE=%~dp0tests\TestResults\FSharp.Core.UnitTests.coreclr.trx
+    if not exist "!LOGFILE!" (
+        echo --------------------------------------------------------
+        echo Test results file !LOGFILE! not found, ensure tests ran.
+        echo --------------------------------------------------------
+        goto :failure
+    )
+
+    set LOGFILE=%TESTLOGDIR%\FSharp.Core.UnitTests_netcoreapp2.0.trx
     echo "%_dotnetexe%" test "%~dp0tests\FSharp.Core.UnitTests\FSharp.Core.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f netcoreapp2.0 -l "trx;LogFileName=!LOGFILE!"
          "%_dotnetexe%" test "%~dp0tests\FSharp.Core.UnitTests\FSharp.Core.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f netcoreapp2.0 -l "trx;LogFileName=!LOGFILE!"
 
@@ -955,14 +999,21 @@ if "%TEST_CORECLR_COREUNIT_SUITE%" == "1" (
         echo ------------------------------------------------------------------
         goto :failure
     )
+
+    if not exist "!LOGFILE!" (
+        echo --------------------------------------------------------
+        echo Test results file !LOGFILE! not found, ensure tests ran.
+        echo --------------------------------------------------------
+        goto :failure
+    )
 )
 
 REM ---------------- coreclr-fsharp  -----------------------
 
 if "%TEST_CORECLR_FSHARP_SUITE%" == "1" (
-    set LOGFILE=%~dp0tests\TestResults\FSharp.Tests.FSharpSuite.coreclr.trx
-    echo "%_dotnetexe%" test "%~dp0tests\fsharp\FSharp.Tests.FSharpSuite.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f netcoreapp2.0 -l "trx;LogFileName=!LOGFILE!" -o "%~dp0%BUILD_CONFIG%\coreclr\bin"
-         "%_dotnetexe%" test "%~dp0tests\fsharp\FSharp.Tests.FSharpSuite.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f netcoreapp2.0 -l "trx;LogFileName=!LOGFILE!" -o "%~dp0%BUILD_CONFIG%\coreclr\bin"
+    set LOGFILE=%TESTLOGDIR%\FSharp.Tests.FSharpSuite_netcoreapp2.0.trx
+    echo "%_dotnetexe%" test "%~dp0tests\fsharp\FSharp.Tests.FSharpSuite.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f netcoreapp2.0 -l "trx;LogFileName=!LOGFILE!"
+         "%_dotnetexe%" test "%~dp0tests\fsharp\FSharp.Tests.FSharpSuite.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f netcoreapp2.0 -l "trx;LogFileName=!LOGFILE!"
 
     if errorlevel 1 (
         echo ----------------------------------------------------------------
@@ -970,12 +1021,19 @@ if "%TEST_CORECLR_FSHARP_SUITE%" == "1" (
         echo ----------------------------------------------------------------
         goto :failure
     )
+
+    if not exist "!LOGFILE!" (
+        echo --------------------------------------------------------
+        echo Test results file !LOGFILE! not found, ensure tests ran.
+        echo --------------------------------------------------------
+        goto :failure
+    )
 )
 
 REM ---------------- vs-ideunit  -----------------------
 
 if "%TEST_VS_IDEUNIT_SUITE%" == "1" (
-    set LOGFILE=%~dp0tests\TestResults\GetTypesVSUnitTests.net40.trx
+    set LOGFILE=%TESTLOGDIR%\GetTypesVSUnitTests_net472.trx
     echo "%_dotnetexe%" test "%~dp0vsintegration\tests\GetTypesVSUnitTests\GetTypesVSUnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
          "%_dotnetexe%" test "%~dp0vsintegration\tests\GetTypesVSUnitTests\GetTypesVSUnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
 
@@ -986,21 +1044,36 @@ if "%TEST_VS_IDEUNIT_SUITE%" == "1" (
         goto :failure
     )
 
-    set LOGFILE=%~dp0tests\TestResults\VisualFSharp.UnitTests.net40.trx
-    echo "%_dotnetexe%" test "%~dp0vsintegration\tests\UnitTests\VisualFSharp.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!" -o "%~dp0%BUILD_CONFIG%\net40\bin"
-         "%_dotnetexe%" test "%~dp0vsintegration\tests\UnitTests\VisualFSharp.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!" -o "%~dp0%BUILD_CONFIG%\net40\bin"
+    if not exist "!LOGFILE!" (
+        echo --------------------------------------------------------
+        echo Test results file !LOGFILE! not found, ensure tests ran.
+        echo --------------------------------------------------------
+        goto :failure
+    )
+
+    set LOGFILE=%TESTLOGDIR%\VisualFSharp.UnitTests_net472.trx
+    echo "%_dotnetexe%" test "%~dp0vsintegration\tests\UnitTests\VisualFSharp.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
+         "%_dotnetexe%" test "%~dp0vsintegration\tests\UnitTests\VisualFSharp.UnitTests.fsproj" --no-restore --no-build -c %BUILD_CONFIG% -f net472 -l "trx;LogFileName=!LOGFILE!"
     if errorlevel 1 (
         echo ------------------------------------------------------------
         echo Error: Running tests vs-ideunit failed, see file `!LOGFILE!`
         echo ------------------------------------------------------------
         goto :failure
     )
+
+    if not exist "!LOGFILE!" (
+        echo --------------------------------------------------------
+        echo Test results file !LOGFILE! not found, ensure tests ran.
+        echo --------------------------------------------------------
+        goto :failure
+    )
 )
 
 goto :success
 REM ------ exit -------------------------------------
 :failure
 endlocal
+@echo
 exit /b 1
 
 :success
diff --git a/build/config/AssemblySignToolData.json b/build/config/AssemblySignToolData.json
index 6857a57f0dd..55163cb5b14 100644
--- a/build/config/AssemblySignToolData.json
+++ b/build/config/AssemblySignToolData.json
@@ -4,55 +4,45 @@
       "certificate": "Microsoft",
       "strongName": "StrongName",
       "values": [
-        "net40\\bin\\FSharp.Core.dll",
-        "net40\\bin\\*\\FSharp.Core.resources.dll",
-        "net40\\bin\\FSharp.Build.dll",
-        "net40\\bin\\*\\FSharp.Build.resources.dll",
-        "net40\\bin\\FSharp.Compiler.Private.dll",
-        "net40\\bin\\*\\FSharp.Compiler.Private.resources.dll",
-        "net40\\bin\\FSharp.Compiler.Server.Shared.dll",
-        "net40\\bin\\FSharp.Compiler.Interactive.Settings.dll",
-        "net40\\bin\\*\\FSharp.Compiler.Interactive.Settings.resources.dll",
-        "net40\\bin\\fsc.exe",
-        "net40\\bin\\fsi.exe",
-        "net40\\bin\\fsiAnyCpu.exe",
-        "net40\\bin\\FSharp.VS.FSI.dll",
-        "net40\\bin\\*\\FSharp.VS.FSI.resources.dll",
-        "net40\\bin\\FSharp.LanguageService.Base.dll",
-        "net40\\bin\\*\\FSharp.LanguageService.Base.resources.dll",
-        "net40\\bin\\FSharp.LanguageService.dll",
-        "net40\\bin\\*\\FSharp.LanguageService.resources.dll",
-        "net40\\bin\\FSharp.UIResources.dll",
-        "net40\\bin\\*\\FSharp.UIResources.resources.dll",
-        "net40\\bin\\FSharp.Editor.dll",
-        "net40\\bin\\*\\FSharp.Editor.resources.dll",
-        "net40\\bin\\FSharp.ProjectSystem.Base.dll",
-        "net40\\bin\\*\\FSharp.ProjectSystem.Base.resources.dll",
-        "net40\\bin\\FSharp.ProjectSystem.PropertyPages.dll",
-        "net40\\bin\\*\\FSharp.ProjectSystem.PropertyPages.resources.dll",
-        "net40\\bin\\FSharp.ProjectSystem.FSharp.dll",
-        "net40\\bin\\*\\FSharp.ProjectSystem.FSharp.resources.dll",
-        "net40\\bin\\FSharp.PatternMatcher.dll",
-        "coreclr\\bin\\FSharp.Core.dll",
-        "coreclr\\bin\\*\\FSharp.Core.resources.dll",
-        "coreclr\\bin\\FSharp.Build.dll",
-        "coreclr\\bin\\*\\FSharp.Build.resources.dll",
-        "coreclr\\bin\\FSharp.Compiler.Private.dll",
-        "coreclr\\bin\\*\\FSharp.Compiler.Private.resources.dll",
-        "coreclr\\bin\\FSharp.Compiler.Interactive.Settings.dll",
-        "coreclr\\bin\\*\\FSharp.Compiler.Interactive.Settings.resources.dll",
-        "coreclr\\bin\\fsc.exe",
-        "coreclr\\bin\\fsi.exe"
+        "bin\\FSharp.Core\\*\\*\\FSharp.Core.dll",
+        "bin\\FSharp.Core\\*\\*\\*\\FSharp.Core.resources.dll",
+        "bin\\FSharp.Build\\*\\*\\FSharp.Build.dll",
+        "bin\\FSharp.Build\\*\\*\\*\\FSharp.Build.resources.dll",
+        "bin\\FSharp.Compiler.Private\\*\\*\\FSharp.Compiler.Private.dll",
+        "bin\\FSharp.Compiler.Private\\*\\*\\*\\FSharp.Compiler.Private.resources.dll",
+        "bin\\FSharp.Compiler.Server.Shared\\*\\*\\FSharp.Compiler.Server.Shared.dll",
+        "bin\\FSharp.Compiler.Interactive.Settings\\*\\*\\FSharp.Compiler.Interactive.Settings.dll",
+        "bin\\FSharp.Compiler.Interactive.Settings\\*\\*\\*\\FSharp.Compiler.Interactive.Settings.resources.dll",
+        "bin\\fsc\\*\\*\\fsc.exe",
+        "bin\\fsi\\*\\*\\fsi.exe",
+        "bin\\fsiAnyCpu\\*\\*\\fsiAnyCpu.exe",
+        "bin\\FSharp.VS.FSI\\*\\*\\FSharp.VS.FSI.dll",
+        "bin\\FSharp.VS.FSI\\*\\*\\*\\FSharp.VS.FSI.resources.dll",
+        "bin\\FSharp.LanguageService.Base\\*\\*\\FSharp.LanguageService.Base.dll",
+        "bin\\FSharp.LanguageService.Base\\*\\*\\*\\FSharp.LanguageService.Base.resources.dll",
+        "bin\\FSharp.LanguageService\\*\\*\\FSharp.LanguageService.dll",
+        "bin\\FSharp.LanguageService\\*\\*\\*\\FSharp.LanguageService.resources.dll",
+        "bin\\FSharp.UIResources\\*\\*\\FSharp.UIResources.dll",
+        "bin\\FSharp.UIResources\\*\\*\\*\\FSharp.UIResources.resources.dll",
+        "bin\\FSharp.Editor\\*\\*\\FSharp.Editor.dll",
+        "bin\\FSharp.Editor\\*\\*\\*\\FSharp.Editor.resources.dll",
+        "bin\\FSharp.PatternMatcher\\*\\*\\FSharp.PatternMatcher.dll",
+        "bin\\FSharp.PropertiesPages\\*\\*\\FSharp.ProjectSystem.PropertyPages.dll",
+        "bin\\FSharp.PropertiesPages\\*\\*\\*\\FSharp.ProjectSystem.PropertyPages.resources.dll",
+        "bin\\ProjectSystem\\*\\*\\FSharp.ProjectSystem.FSharp.dll",
+        "bin\\ProjectSystem\\*\\*\\*\\FSharp.ProjectSystem.FSharp.resources.dll",
+        "bin\\ProjectSystem.Base\\*\\*\\FSharp.ProjectSystem.Base.dll",
+        "bin\\ProjectSystem.Base\\*\\*\\*\\FSharp.ProjectSystem.Base.resources.dll"
       ]
     },
     {
       "certificate": "VsixSHA2",
       "strongName": null,
       "values": [
-        "net40\\bin\\VisualFSharpFull.vsix",
-        "net40\\bin\\VisualFSharpTemplate.vsix",
-        "insertion\\Microsoft.FSharp.Dependencies.vsix",
-        "insertion\\Microsoft.FSharp.VSIX.Full.Resources.*.vsix"
+        "bin\\VisualFSharpFull\\*\\*VisualFSharpFull.vsix",
+        "bin\\VisualFSharpTemplates\\*\\*\\VisualFSharpTemplate.vsix",
+        "VSSetup\\*\\Insertion\\Microsoft.FSharp.Dependencies.vsix",
+        "VSSetup\\*\\Insertion\\Microsoft.FSharp.VSIX.Full.Resources.*.vsix"
       ]
     }
   ],
diff --git a/build/config/InsertionSignToolData.json b/build/config/InsertionSignToolData.json
index ec8432ca9ad..d81579b12c9 100644
--- a/build/config/InsertionSignToolData.json
+++ b/build/config/InsertionSignToolData.json
@@ -4,11 +4,11 @@
       "certificate": "VsixSHA2",
       "strongName": null,
       "values": [
-        "insertion\\Microsoft.FSharp.Compiler.vsix",
-        "insertion\\Microsoft.FSharp.Compiler.Resources.*.vsix",
-        "insertion\\Microsoft.FSharp.Dependencies.vsix",
-        "insertion\\Microsoft.FSharp.IDE.vsix",
-        "insertion\\Microsoft.FSharp.SDK.vsix"
+        "Microsoft.FSharp.Compiler.vsix",
+        "Microsoft.FSharp.Compiler.Resources.*.vsix",
+        "Microsoft.FSharp.Dependencies.vsix",
+        "Microsoft.FSharp.IDE.vsix",
+        "Microsoft.FSharp.SDK.vsix"
       ]
     }
   ],
diff --git a/build/config/PackageSignToolData.json b/build/config/PackageSignToolData.json
index 20007f59e36..5bc74386355 100644
--- a/build/config/PackageSignToolData.json
+++ b/build/config/PackageSignToolData.json
@@ -4,8 +4,7 @@
         "certificate": "NuGet",
         "strongName": null,
         "values": [
-          "artifacts\\*.nupkg",
-          "artifacts\\*\\*.nupkg"
+          "*.nupkg"
         ]
       }
     ],
diff --git a/build/projects/Signing.proj b/build/projects/Signing.proj
index 4999fb6d085..9e981e135ec 100644
--- a/build/projects/Signing.proj
+++ b/build/projects/Signing.proj
@@ -3,7 +3,6 @@
   <PropertyGroup>
     <!-- necessary for package restore -->
     <TargetFramework>net46</TargetFramework>
-    <BinaryLocation>$(RepoRoot)$(Configuration)</BinaryLocation>
     <SignToolExe>$(NuGetPackageRoot)RoslynTools.SignTool\$(RoslynToolsSignToolPackageVersion)\tools\SignTool.exe</SignToolExe>
     <SignToolArgs>-msbuildPath "$(MSBuildBinPath)\msbuild.exe" -nugetPackagesPath "$(NuGetPackageRoot.TrimEnd('\'))" -config "$(ConfigFile)"</SignToolArgs>
     <SignToolArgs Condition="'$(SignType)' == 'test'">-testSign $(SignToolArgs)</SignToolArgs>
@@ -17,11 +16,12 @@
   <Target Name="ValidateArguments">
     <Error Message="Configuration must be manually specified." Condition="'$(Configuration)' == ''" />
     <Error Message="Configuration file must be manually specified." Condition="'$(ConfigFile)' == ''" />
+    <Error Message="BinaryBasePath must be manually specified." Condition="'$(BinaryBasePath)' == ''" />
   </Target>
 
   <Target Name="DoSigning"
           DependsOnTargets="ValidateArguments">
-    <Exec Command='"$(SignToolExe)" $(SignToolArgs) "$(BinaryLocation)"' />
+    <Exec Command='"$(SignToolExe)" $(SignToolArgs) "$(BinaryBasePath)"' />
   </Target>
 
 </Project>
diff --git a/build/targets/AssemblyVersions.props b/build/targets/AssemblyVersions.props
index 3e8a9118359..8041d019ad4 100644
--- a/build/targets/AssemblyVersions.props
+++ b/build/targets/AssemblyVersions.props
@@ -30,7 +30,7 @@
     <FSProductVersion>$(FSPackageVersion).0</FSProductVersion>
 
     <VSMajorVersion>16</VSMajorVersion>
-    <VSMinorVersion>0</VSMinorVersion>
+    <VSMinorVersion>1</VSMinorVersion>
     <VSGeneralVersion>$(VSMajorVersion).0</VSGeneralVersion>
     <VSAssemblyVersion>$(VSMajorVersion).$(VSMinorVersion).0.0</VSAssemblyVersion>
 
diff --git a/build/targets/ConvertPortablePdbs.targets b/build/targets/ConvertPortablePdbs.targets
index 474fe091a5d..c43042a499e 100644
--- a/build/targets/ConvertPortablePdbs.targets
+++ b/build/targets/ConvertPortablePdbs.targets
@@ -6,20 +6,33 @@
 
   <Target Name="ConvertPortablePdbs"
           AfterTargets="AfterBuild"
-          DependsOnTargets="ComputeFinalOutputPaths"
           Condition="'$(OS)' != 'Unix' AND
                      Exists('$(TargetPath)') AND
                      ('$(DebugType)' == 'portable' OR '$(DebugType)' == 'embedded') AND
                      $(TargetFramework.StartsWith('net4')) AND
                      '$(Configuration)' != 'Proto'">
     <PropertyGroup>
-      <ConvertedPdbsDirectory>$(FinalOutputPath)\ConvertedPdbs</ConvertedPdbsDirectory>
       <PdbConverterExe>$(NuGetPackageRoot)Pdb2Pdb\$(Pdb2PdbPackageVersion)\tools\Pdb2Pdb.exe</PdbConverterExe>
-      <PdbConverterArgs>"$(TargetPath)" /out "$(ConvertedPdbsDirectory)\$(TargetName).pdb" /srcsvrvar SRC_INDEX=public</PdbConverterArgs>
+      <PdbConverterArgs>"$(TargetPath)" /out "$(SymStoreDirectory)\$(TargetName).pdb" /srcsvrvar SRC_INDEX=public</PdbConverterArgs>
     </PropertyGroup>
 
-    <MakeDir Directories="$(ConvertedPdbsDirectory)" />
+    <MakeDir Directories="$(SymStoreDirectory)" />
     <Exec Command='"$(PdbConverterExe)" $(PdbConverterArgs)' />
   </Target>
 
+  <Target Name="CopyExtantFullPdbs"
+          AfterTargets="AfterBuild"
+          Condition="'$(OS)' != 'Unix' AND
+                     Exists('$(TargetPath)') AND
+                     '$(DebugType)' == 'full' AND
+                     $(TargetFramework.StartsWith('net4')) AND
+                     '$(Configuration)' != 'Proto'">
+    <PropertyGroup>
+      <PdbFileName>$(TargetDir)\$(TargetName).pdb</PdbFileName>
+    </PropertyGroup>
+
+    <MakeDir Directories="$(SymStoreDirectory)" />
+    <Copy SourceFiles="$(PdbFileName)" DestinationFolder="$(SymStoreDirectory)" />
+  </Target>
+
 </Project>
diff --git a/build/targets/GenerateAssemblyAttributes.targets b/build/targets/GenerateAssemblyAttributes.targets
index 1be6bdb8315..7b747c9dd92 100644
--- a/build/targets/GenerateAssemblyAttributes.targets
+++ b/build/targets/GenerateAssemblyAttributes.targets
@@ -82,8 +82,7 @@
           Inputs="$(MSBuildThisFileFullPath);$(MSBuildProjectFile)"
           Outputs="$(GeneratedFSharpAssemblyVersionFile)"
           DependsOnTargets="PrepareGenerateAssemblyFileVersion;PrepareForBuild"
-          BeforeTargets="CoreCompile"
-          Condition="'$(Configuration)' != 'Proto'">
+          BeforeTargets="CoreCompile">
 
     <WriteCodeFragment AssemblyAttributes="@(_AssemblyVersionAttributes)"
                        Language="$(Language)"
diff --git a/build/targets/NGenOrCrossGen.targets b/build/targets/NGenOrCrossGen.targets
new file mode 100644
index 00000000000..33dcaa3a63a
--- /dev/null
+++ b/build/targets/NGenOrCrossGen.targets
@@ -0,0 +1,36 @@
+<Project>
+
+  <Target Name="NGenWindowsBinaries"
+          AfterTargets="AfterBuild"
+          DependsOnTargets="CheckAdministratorPrivilege"
+          Condition="'$(OS)' != 'Unix' AND
+                     $(TargetFramework.StartsWith('net4')) AND 
+                     '$(NGenBinary)' == 'true' AND
+                     Exists('$(TargetPath)') ">
+    <PropertyGroup>
+      <PathToNGen64>$(windir)\Microsoft.NET\Framework64\v4.0.30319\ngen.exe</PathToNGen64>
+      <PathToNGen32>$(windir)\Microsoft.NET\Framework\v4.0.30319\ngen.exe</PathToNGen32>
+    </PropertyGroup>
+
+    <!-- 
+        NGen for both 32 and 64 bit product.
+        If compiling use the app config file, if present.
+    -->
+    <Exec Command='"$(PathToNGen64)" install "$(TargetPath)" /ExeConfig:$(TargetPath)' Condition = "Exists('$(PathToNGen64)') AND Exists('$(TargetPath).config') AND '$(IsAdministrator)' == 'true'"/>
+    <Exec Command='"$(PathToNGen32)" install "$(TargetPath)" /ExeConfig:$(TargetPath)' Condition = "Exists('$(PathToNGen32)') AND Exists('$(TargetPath).config') AND '$(IsAdministrator)' == 'true'"/>
+    <Exec Command='"$(PathToNGen64)" install "$(TargetPath)"' Condition = " Exists('$(PathToNGen64)') AND (!Exists('$(TargetPath).config')) AND '$(IsAdministrator)' == 'true' "/>
+    <Exec Command='"$(PathToNGen32)" install "$(TargetPath)"' Condition = " Exists('$(PathToNGen32)') AND (!Exists('$(TargetPath).config')) AND '$(IsAdministrator)' == 'true' "/>
+  </Target>
+
+  <!-- Amazingly the net session command returns 0 if in an administrator session and > 0 if not --> 
+  <Target Name="CheckAdministratorPrivilege" Condition="'$(OS)' != 'Unix'">
+    <Exec Command="NET SESSION" ConsoleToMSBuild="false" ContinueOnError="true">
+      <Output TaskParameter="ExitCode" PropertyName="ErrorCode"/>
+    </Exec>
+    <PropertyGroup>
+      <IsAdministrator Condition = " '$(ErrorCode)' == '0' ">true</IsAdministrator>
+      <IsAdministrator Condition = " '$(ErrorCode)' != '0' ">false</IsAdministrator>
+    </PropertyGroup>
+  </Target>
+
+</Project>
diff --git a/build/targets/PackageVersions.props b/build/targets/PackageVersions.props
index e4c29f52e87..97165c5feeb 100644
--- a/build/targets/PackageVersions.props
+++ b/build/targets/PackageVersions.props
@@ -19,7 +19,7 @@
 
     <!-- synchronized build package sources -->
     <RestoreSources Condition="'$(PB_RestoreSource)' != ''">$(PB_RestoreSource);$(RestoreSources)</RestoreSources>
-    <DotNetPackageVersionPropsPath>$(MSBuildThisFileDirectory)..\..\Tools\dependencyUptake\PackageVersions.props</DotNetPackageVersionPropsPath>
+    <DotNetPackageVersionPropsPath>$(MSBuildThisFileDirectory)..\..\artifacts\dependencyUptake\PackageVersions.props</DotNetPackageVersionPropsPath>
 
     <!-- version numbers from files -->
     <RoslynPackageVersion>$([System.IO.File]::ReadAllText('$(MSBuildThisFileDirectory)..\..\RoslynPackageVersion.txt').Trim())</RoslynPackageVersion>
@@ -133,9 +133,9 @@
     <MicrosoftVisualFSharpTypeProvidersRedistPackageVersion>1.0.0</MicrosoftVisualFSharpTypeProvidersRedistPackageVersion>
     <MicrosoftWin32RegistryPackageVersion>4.3.0</MicrosoftWin32RegistryPackageVersion>
     <NewtonsoftJsonPackageVersion>9.0.1</NewtonsoftJsonPackageVersion>
-    <NUnitPackageVersion>3.10.1</NUnitPackageVersion>
-    <NUnit3TestAdapterPackageVersion>3.10.0</NUnit3TestAdapterPackageVersion>
-    <NUnitLitePackageVersion>3.10.1</NUnitLitePackageVersion>
+    <NUnitPackageVersion>3.11.0</NUnitPackageVersion>
+    <NUnit3TestAdapterPackageVersion>3.11.2</NUnit3TestAdapterPackageVersion>
+    <NUnitLitePackageVersion>3.11.0</NUnitLitePackageVersion>
     <RoslynToolsSignToolPackageVersion>1.0.0-beta2-dev3</RoslynToolsSignToolPackageVersion>
     <StrawberryPerl64PackageVersion>5.22.2.1</StrawberryPerl64PackageVersion>
     <XliffTasksPackageVersion>0.2.0-beta-000081</XliffTasksPackageVersion>
diff --git a/fcs/Directory.Build.props b/fcs/Directory.Build.props
index cdcbdd4b8b3..6535dbd2aea 100644
--- a/fcs/Directory.Build.props
+++ b/fcs/Directory.Build.props
@@ -4,17 +4,19 @@
     <NuGetPackageRoot Condition="'$(NuGetPackageRoot)' == '' AND '$(OS)' != 'Windows_NT'">$(HOME)/.nuget/packages/</NuGetPackageRoot>
     <NuGetPackageRoot Condition="!HasTrailingSlash('$(NuGetPackageRoot)') AND '$(OS)' == 'Windows_NT'">$(NuGetPackageRoot)\</NuGetPackageRoot>
     <NuGetPackageRoot Condition="!HasTrailingSlash('$(NuGetPackageRoot)') AND '$(OS)' != 'Windows_NT'">$(NuGetPackageRoot)/</NuGetPackageRoot>
+    <ArtifactsDir>$(MSBuildThisFileDirectory)..\artifacts</ArtifactsDir>
+    <ArtifactsBinDir>$(ArtifactsDir)\bin</ArtifactsBinDir>
+    <ArtifactsObjDir>$(ArtifactsDir)\obj</ArtifactsObjDir>
+    <OutputPath>$(ArtifactsBinDir)\fcs</OutputPath>
+    <IntermediateOutputPath>$(ArtifactsObjDir)\fcs</IntermediateOutputPath>
   </PropertyGroup>
 
   <!-- SDK targets override -->
   <PropertyGroup>
-    <ProtoOutputPath>$(MSBuildThisFileDirectory)..\Proto\net40\bin</ProtoOutputPath>
+    <ProtoOutputPath>$(ArtifactsBinDir)\FSharp.Build\Proto\net46</ProtoOutputPath>
   </PropertyGroup>
 
   <PropertyGroup Condition="Exists('$(ProtoOutputPath)')">
-    <!-- <FscToolPath>$(ProtoOutputPath)\</FscToolPath>
-    <FscToolExe>fsc.exe</FscToolExe>
-    <DotnetFscCompilerPath>- -nologo</DotnetFscCompilerPath> -->
     <FSharpTargetsPath>$(ProtoOutputPath)\Microsoft.FSharp.Targets</FSharpTargetsPath>
     <FSharpPropsShim>$(ProtoOutputPath)\Microsoft.FSharp.NetSdk.props</FSharpPropsShim>
     <FSharpTargetsShim>$(ProtoOutputPath)\Microsoft.FSharp.NetSdk.targets</FSharpTargetsShim>
diff --git a/fcs/FSharp.Compiler.Service.MSBuild.v12/FSharp.Compiler.Service.MSBuild.v12.fsproj b/fcs/FSharp.Compiler.Service.MSBuild.v12/FSharp.Compiler.Service.MSBuild.v12.fsproj
index 5e5c306711f..4f57056e404 100644
--- a/fcs/FSharp.Compiler.Service.MSBuild.v12/FSharp.Compiler.Service.MSBuild.v12.fsproj
+++ b/fcs/FSharp.Compiler.Service.MSBuild.v12/FSharp.Compiler.Service.MSBuild.v12.fsproj
@@ -7,7 +7,6 @@
   <PropertyGroup>
     <TargetFrameworks>net45</TargetFrameworks>
     <DisableImplicitFSharpCoreReference>true</DisableImplicitFSharpCoreReference>
-    <OutputPath>..\..\$(Configuration.ToLower())\fcs</OutputPath>
     <DefineConstants>$(DefineConstants);CROSS_PLATFORM_COMPILER</DefineConstants>
     <DefineConstants>$(DefineConstants);ENABLE_MONO_SUPPORT</DefineConstants>
   </PropertyGroup>
diff --git a/fcs/FSharp.Compiler.Service.ProjectCracker/FSharp.Compiler.Service.ProjectCracker.fsproj b/fcs/FSharp.Compiler.Service.ProjectCracker/FSharp.Compiler.Service.ProjectCracker.fsproj
index 486b2483294..5bbb337e36a 100644
--- a/fcs/FSharp.Compiler.Service.ProjectCracker/FSharp.Compiler.Service.ProjectCracker.fsproj
+++ b/fcs/FSharp.Compiler.Service.ProjectCracker/FSharp.Compiler.Service.ProjectCracker.fsproj
@@ -1,13 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
-  <PropertyGroup>
-    <FSharpSourcesRoot>$(MSBuildProjectDirectory)\..\..\src</FSharpSourcesRoot>
-  </PropertyGroup>
   <Import Project="..\fcs.props" />
   <Import Project="..\netfx.props" />
   <PropertyGroup>
     <TargetFrameworks>net45</TargetFrameworks>
     <DisableImplicitFSharpCoreReference>true</DisableImplicitFSharpCoreReference>
-    <OutputPath>..\..\$(Configuration.ToLower())\fcs</OutputPath>
   </PropertyGroup>
   <PropertyGroup>
     <Description>Legacy project file cracker for the F# compiler service.</Description>
@@ -25,8 +21,8 @@
     </Compile>
     <Compile Include="ProjectCracker.fs" />
     <Content Include="..\FSharp.Compiler.Service.ProjectCrackerTool\FSharp.Compiler.Service.ProjectCracker.targets" PackagePath="build\net45" />
-    <Content Include="..\..\release\fcs\net45\FSharp.Compiler.Service.ProjectCrackerTool.exe" PackagePath="utilities\net45" />
-    <Content Include="..\..\release\fcs\net45\FSharp.Compiler.Service.ProjectCrackerTool.exe.config" PackagePath="utilities\net45" />
+    <Content Include="$(ArtifactsBinDir)\fcs\net45\FSharp.Compiler.Service.ProjectCrackerTool.exe" PackagePath="utilities\net45" />
+    <Content Include="$(ArtifactsBinDir)\fcs\net45\FSharp.Compiler.Service.ProjectCrackerTool.exe.config" PackagePath="utilities\net45" />
   </ItemGroup>
   <ItemGroup>
     <Reference Include="System.Runtime" />
diff --git a/fcs/FSharp.Compiler.Service.ProjectCrackerTool/FSharp.Compiler.Service.ProjectCrackerTool.fsproj b/fcs/FSharp.Compiler.Service.ProjectCrackerTool/FSharp.Compiler.Service.ProjectCrackerTool.fsproj
index 9dddb1cb616..9f690c58ea1 100644
--- a/fcs/FSharp.Compiler.Service.ProjectCrackerTool/FSharp.Compiler.Service.ProjectCrackerTool.fsproj
+++ b/fcs/FSharp.Compiler.Service.ProjectCrackerTool/FSharp.Compiler.Service.ProjectCrackerTool.fsproj
@@ -13,7 +13,6 @@
     <OtherFlags>$(OtherFlags) --staticlink:FSharp.Core</OtherFlags>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
     <IsPackable>false</IsPackable>
-    <OutputPath>..\..\$(Configuration.ToLower())\fcs</OutputPath>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="ProjectCrackerOptions.fs" />
diff --git a/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj b/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
index 86f4f69ed09..55696e34ffe 100644
--- a/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
+++ b/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
@@ -12,6 +12,7 @@
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
     <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies> <!-- Tests won't run without this, at least on OSX, see https://github.com/NuGet/Home/issues/4837#issuecomment-354536302 -->
   </PropertyGroup>
   <PropertyGroup Condition="'$(TargetFramework)' == 'netcoreapp2.0'">
@@ -67,6 +68,12 @@
     <Compile Include="$(FSharpSourcesRoot)\..\tests\service\TokenizerTests.fs">
       <Link>TokenizerTests.fs</Link>
     </Compile>
+    <Compile Include="$(FSharpSourcesRoot)\..\tests\service\ServiceUntypedParseTests.fs">
+      <Link>ServiceUntypedParseTests.fs</Link>
+    </Compile>
+    <Compile Include="$(FSharpSourcesRoot)\..\tests\service\TreeVisitorTests.fs">
+      <Link>TreeVisitorTests.fs</Link>
+    </Compile>
     <Compile Include="$(FSharpSourcesRoot)\..\tests\service\Program.fs" Condition="'$(TargetFramework)' == 'netcoreapp2.0'">
       <Link>Program.fs</Link>
     </Compile>
@@ -77,7 +84,7 @@
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.6.0" />
     <PackageReference Include="NUnit" Version="3.9.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.9.0" />
-    <PackageReference Include="Dotnet.ProjInfo" Version="0.9.0" />
+    <PackageReference Include="Dotnet.ProjInfo" Version="0.20.0" />
     <ProjectReference Include="..\FSharp.Compiler.Service\FSharp.Compiler.Service.fsproj" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'net46'">
diff --git a/fcs/FSharp.Compiler.Service/FSharp.Compiler.Service.fsproj b/fcs/FSharp.Compiler.Service/FSharp.Compiler.Service.fsproj
index 4e7d3e4573e..8b23b7fa1da 100644
--- a/fcs/FSharp.Compiler.Service/FSharp.Compiler.Service.fsproj
+++ b/fcs/FSharp.Compiler.Service/FSharp.Compiler.Service.fsproj
@@ -12,13 +12,12 @@
     <DefineConstants>$(DefineConstants);COMPILER</DefineConstants>
     <DefineConstants>$(DefineConstants);ENABLE_MONO_SUPPORT</DefineConstants>
     <DefineConstants>$(DefineConstants);NO_STRONG_NAMES</DefineConstants>
-    <OutputPath>..\..\$(Configuration.ToLower())\fcs</OutputPath>
     <FsLexOutputFolder Condition="'$(TargetFramework)' != ''">$(TargetFramework)\</FsLexOutputFolder>
     <FsYaccOutputFolder Condition="'$(TargetFramework)' != ''">$(TargetFramework)\</FsYaccOutputFolder>
     <OtherFlags>$(OtherFlags) /warnon:1182</OtherFlags>
     <OtherFlags>$(OtherFlags) --times</OtherFlags>
     <NoWarn>$(NoWarn);44;62;69;65;54;61;75;62;9;2003;NU5125</NoWarn>
-    <Tailcalls>true</Tailcalls>
+    <Tailcalls>true</Tailcalls> <!-- .tail annotations always emitted for this binary, even in debug mode -->
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
   </PropertyGroup>
diff --git a/fcs/build.fsx b/fcs/build.fsx
index e303edee10d..8549ed86348 100644
--- a/fcs/build.fsx
+++ b/fcs/build.fsx
@@ -13,8 +13,8 @@ open Fake.ReleaseNotesHelper
 #if MONO
 // prevent incorrect output encoding (e.g. https://github.com/fsharp/FAKE/issues/1196)
 System.Console.OutputEncoding <- System.Text.Encoding.UTF8
-CleanDir (__SOURCE_DIRECTORY__ + "/../tests/TestResults") 
-File.WriteAllText(__SOURCE_DIRECTORY__ + "/../tests/TestResults/notestsyet.txt","No tests yet")
+CleanDir (__SOURCE_DIRECTORY__ + "/../artifacts/TestResults") 
+File.WriteAllText(__SOURCE_DIRECTORY__ + "/../artifacts/TestResults/notestsyet.txt","No tests yet")
 let isMono = true
 #else
 let isMono = false
@@ -54,7 +54,7 @@ let runCmdIn workDir (exe:string) = Printf.ksprintf (fun (args:string) ->
 // The rest of the code is standard F# build script
 // --------------------------------------------------------------------------------------
 
-let releaseDir = Path.Combine(__SOURCE_DIRECTORY__, "../release/fcs")
+let releaseDir = Path.Combine(__SOURCE_DIRECTORY__, "../artifacts/bin/fcs")
 
 // Read release notes & version info from RELEASE_NOTES.md
 let release = LoadReleaseNotes (__SOURCE_DIRECTORY__ + "/RELEASE_NOTES.md")
diff --git a/fsharp.proj b/fsharp.proj
index 42d2f15b16f..47327528bcf 100644
--- a/fsharp.proj
+++ b/fsharp.proj
@@ -11,6 +11,7 @@
     <BuildVS Condition="'$(BuildVS)' == ''">false</BuildVS>
     <BuildFCS Condition="'$(BuildFCS)' == ''">false</BuildFCS>
     <BuildSetup Condition="'$(BuildSetup)' == ''">false</BuildSetup>
+    <BuildNuget Condition="'$(BuildNuget)' == ''">false</BuildNuget>
 
     <TestCompiler Condition="'$(TestCompiler)' == ''">false</TestCompiler>
     <TestFSharpSuite Condition="'$(TestFSharpSuite)' == ''">false</TestFSharpSuite>
@@ -25,6 +26,7 @@
     <BuildCompiler Condition="'$(BUILD_CORECLR)' == '1'">true</BuildCompiler>
     <BuildVS Condition="'$(BUILD_VS)' == '1'">true</BuildVS>
     <BuildFCS Condition="'$(BUILD_FCS)' == '1'">true</BuildFCS>
+    <BuildNuget Condition="'$(BUILD_NUGET)' == '1' or '$(BUILD_SETUP)' == '1'">true</BuildNuget>
     <BuildSetup Condition="'$(BUILD_SETUP)' == '1'">true</BuildSetup>
 
     <TestCompiler Condition="'$(TEST_NET40_COMPILERUNIT_SUITE)' == '1'">true</TestCompiler>
@@ -36,30 +38,59 @@
     <TestIDE Condition="'$(TEST_VS_IDEUNIT_SUITE)' == '1'">true</TestIDE>
   </PropertyGroup>
 
+  <!--
+    If NET40 was specified then build desktop only
+    if NETCORE was specified then build the coreclr only
+    otherwise build it all
+  -->
+  <PropertyGroup>
+    <BuildNetcore Condition="'$(BUILD_NET40)' != '1'and '$(BUILD_CORECLR)' == '1'">true</BuildNetcore>
+    <BuildDesktop Condition="'$(BUILD_NET40)' == '1' and '$(BUILD_CORECLR)' != '1'">true</BuildDesktop>
+  </PropertyGroup>
+
   <Target Name="CollectProjects">
 
     <!-- product binaries -->
-
     <ItemGroup Condition="'$(BuildCompiler)' == 'true' OR '$(_RunningRestore)' == 'true'">
-      <Projects Include="src\fsharp\FSharp.Core\FSharp.Core.fsproj" />
-      <Projects Include="src\fsharp\FSharp.Build\FSharp.Build.fsproj" />
-      <Projects Include="src\fsharp\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj" />
-      <Projects Include="src\fsharp\FSharp.Compiler.Server.Shared\FSharp.Compiler.Server.Shared.fsproj" />
-      <Projects Include="src\fsharp\FSharp.Compiler.Interactive.Settings\FSharp.Compiler.Interactive.Settings.fsproj" />
-      <Projects Include="src\fsharp\Fsc\Fsc.fsproj" />
-      <Projects Include="src\fsharp\fsi\Fsi.fsproj" />
-      <Projects Include="src\fsharp\fsiAnyCpu\FsiAnyCPU.fsproj" />
-
-      <NugetProjects Include="src\fsharp\FSharp.Compiler.nuget\Microsoft.FSharp.Compiler.csproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)src\fsharp\FSharp.Core\FSharp.Core.fsproj">
+        <AdditionalProperties Condition="'$(BuildNetcore)' == 'true'">TargetFramework=netstandard1.6</AdditionalProperties>
+        <AdditionalProperties Condition="'$(BuildDesktop)' == 'true'">TargetFramework=net45</AdditionalProperties>
+      </Projects>
+      <Projects Include="$(MSBuildThisFileDirectory)src\fsharp\FSharp.Build\FSharp.Build.fsproj">
+        <AdditionalProperties Condition="'$(BuildNetcore)' == 'true'">TargetFramework=netstandard2.0</AdditionalProperties>
+        <AdditionalProperties Condition="'$(BuildDesktop)' == 'true'">TargetFramework=net472</AdditionalProperties>
+      </Projects>
+      <Projects Include="$(MSBuildThisFileDirectory)src\fsharp\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj">
+        <AdditionalProperties Condition="'$(BuildNetcore)' == 'true'">TargetFramework=netstandard1.6</AdditionalProperties>
+        <AdditionalProperties Condition="'$(BuildDesktop)' == 'true'">TargetFramework=net472</AdditionalProperties>
+      </Projects>
+      <Projects Include="$(MSBuildThisFileDirectory)src\fsharp\FSharp.Compiler.Server.Shared\FSharp.Compiler.Server.Shared.fsproj">
+        <AdditionalProperties Condition="'$(BuildDesktop)' == 'true'">TargetFramework=net472</AdditionalProperties>
+      </Projects>
+      <Projects Include="$(MSBuildThisFileDirectory)src\fsharp\FSharp.Compiler.Interactive.Settings\FSharp.Compiler.Interactive.Settings.fsproj">
+        <AdditionalProperties Condition="'$(BuildNetcore)' == 'true'">TargetFramework=netstandard1.6</AdditionalProperties>
+        <AdditionalProperties Condition="'$(BuildDesktop)' == 'true'">TargetFramework=net472</AdditionalProperties>
+      </Projects>
+      <Projects Include="$(MSBuildThisFileDirectory)src\fsharp\fsc\fsc.fsproj">
+        <AdditionalProperties Condition="'$(BuildNetcore)' == 'true'">TargetFramework=netcoreapp2.1</AdditionalProperties>
+        <AdditionalProperties Condition="'$(BuildDesktop)' == 'true'">TargetFramework=net472</AdditionalProperties>
+      </Projects>
+      <Projects Include="$(MSBuildThisFileDirectory)src\fsharp\fsi\fsi.fsproj">
+        <AdditionalProperties Condition="'$(BuildNetcore)' == 'true'">TargetFramework=netcoreapp2.1</AdditionalProperties>
+        <AdditionalProperties Condition="'$(BuildDesktop)' == 'true'">TargetFramework=net472</AdditionalProperties>
+      </Projects>
+      <Projects Include="$(MSBuildThisFileDirectory)src\fsharp\fsiAnyCpu\fsiAnyCPU.fsproj">
+        <AdditionalProperties Condition="'$(BuildDesktop)' == 'true'">TargetFramework=net472</AdditionalProperties>
+      </Projects>
     </ItemGroup>
 
     <ItemGroup Condition="'$(BuildVS)' == 'true' OR '$(_RunningRestore)' == 'true'">
-      <Projects Include="vsintegration\fsharp-vsintegration-src-build.proj" />
-      <Projects Include="vsintegration\fsharp-vsintegration-unittests-build.proj" />
-      <Projects Include="vsintegration\Utils\LanguageServiceProfiling\LanguageServiceProfiling.fsproj" />
-      <Projects Include="vsintegration\fsharp-vsintegration-item-templates-build.proj" />
-      <Projects Include="vsintegration\fsharp-vsintegration-project-templates-build.proj" />
-      <Projects Include="vsintegration\fsharp-vsintegration-vsix-build.proj" />
+      <Projects Include="$(MSBuildThisFileDirectory)vsintegration\fsharp-vsintegration-src-build.proj" />
+      <Projects Include="$(MSBuildThisFileDirectory)vsintegration\fsharp-vsintegration-unittests-build.proj" />
+      <Projects Include="$(MSBuildThisFileDirectory)vsintegration\Utils\LanguageServiceProfiling\LanguageServiceProfiling.fsproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)vsintegration\fsharp-vsintegration-item-templates-build.proj" />
+      <Projects Include="$(MSBuildThisFileDirectory)vsintegration\fsharp-vsintegration-project-templates-build.proj" />
+      <Projects Include="$(MSBuildThisFileDirectory)vsintegration\fsharp-vsintegration-vsix-build.proj" />
     </ItemGroup>
 
     <ItemGroup Condition="'$(BuildFCS)' == 'true' OR '$(_RunningRestore)' == 'true'">
@@ -69,42 +100,46 @@
       <Projects Include="$(MSBuildThisFileDirectory)fcs\FSharp.Compiler.Service.ProjectCrackerTool\FSharp.Compiler.Service.ProjectCrackerTool.fsproj" />
     </ItemGroup>
 
+    <ItemGroup Condition="'$(BuildNuget)' == 'true' OR '$(_RunningRestore)' == 'true'">
+      <NugetProjects Include="$(MSBuildThisFileDirectory)src\fsharp\FSharp.Compiler.nuget\Microsoft.FSharp.Compiler.csproj" />
+      <NugetProjects Include="$(MSBuildThisFileDirectory)src\fsharp\FSharp.Compiler.nuget\Microsoft.FSharp.Compiler.Prerelease.csproj" />
+    </ItemGroup>
+
     <ItemGroup Condition="'$(BuildSetup)' == 'true' OR '$(_RunningRestore)' == 'true'">
-      <Projects Include="setup\fsharp-setup-build.csproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)setup\fsharp-setup-build.csproj" />
     </ItemGroup>
 
     <!-- test binaries -->
 
     <ItemGroup Condition="'$(TestCompiler)' == 'true' OR '$(_RunningRestore)' == 'true'">
-      <Projects Include="tests\FSharp.Build.UnitTests\FSharp.Build.UnitTests.fsproj" />
-      <Projects Include="tests\FSharp.Compiler.UnitTests\FSharp.Compiler.UnitTests.fsproj" />
-      <Projects Include="tests\FSharp.Core.UnitTests\FSharp.Core.UnitTests.fsproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)tests\FSharp.Build.UnitTests\FSharp.Build.UnitTests.fsproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)tests\FSharp.Compiler.UnitTests\FSharp.Compiler.UnitTests.fsproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)tests\FSharp.Core.UnitTests\FSharp.Core.UnitTests.fsproj" />
     </ItemGroup>
 
     <ItemGroup Condition="'$(TestFSharpSuite)' == 'true' OR '$(_RunningRestore)' == 'true'">
-      <Projects Include="tests\fsharp\FSharp.Tests.FSharpSuite.fsproj" />
-      <Projects Include="tests\fsharp\SDKTests\AllSdkTargetsTests.proj" />
-      <Projects Include="tests\fsharpqa\testenv\src\PEVerify\PEVerify.csproj" />
-      <Projects Include="src\fsharp\FSharp.Compiler.nuget\Testing.FSharp.Compiler.csproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)tests\fsharp\FSharp.Tests.FSharpSuite.fsproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)tests\fsharp\SDKTests\AllSdkTargetsTests.proj" />
+      <Projects Include="$(MSBuildThisFileDirectory)tests\fsharpqa\testenv\src\PEVerify\PEVerify.csproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)src\fsharp\FSharp.Compiler.nuget\Testing.FSharp.Compiler.csproj" />
 
-      <NugetProjects Include="src\fsharp\FSharp.Compiler.nuget\Testing.FSharp.Compiler.csproj" />
+      <NugetProjects Include="$(MSBuildThisFileDirectory)src\fsharp\FSharp.Compiler.nuget\Testing.FSharp.Compiler.csproj" />
     </ItemGroup>
 
     <ItemGroup Condition="'$(TestFSharpQASuite)' == 'true' OR '$(_RunningRestore)' == 'true'">
-      <Projects Include="tests\fsharpqa\testenv\src\ILComparer\ILComparer.fsproj" />
-      <Projects Include="tests\fsharpqa\testenv\src\HostedCompilerServer\HostedCompilerServer.fsproj" />
-      <Projects Include="tests\fsharpqa\testenv\src\PEVerify\PEVerify.csproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)tests\fsharpqa\testenv\src\ILComparer\ILComparer.fsproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)tests\fsharpqa\testenv\src\HostedCompilerServer\HostedCompilerServer.fsproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)tests\fsharpqa\testenv\src\PEVerify\PEVerify.csproj" />
     </ItemGroup>
 
     <ItemGroup Condition="'$(TestFCS)' == 'true' OR '$(_RunningRestore)' == 'true'">
-      <Projects Include="fcs\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj" />
-      <Projects Include="tests\projects\Sample_NETCoreSDK_FSharp_Library_netstandard2_0\Sample_NETCoreSDK_FSharp_Library_netstandard2_0.fsproj" />
-      <Projects Include="tests\projects\Sample_NETCoreSDK_FSharp_Library_netstandard2_0\Sample_NETCoreSDK_FSharp_Library_netstandard2_0.fsproj" />
-      <Projects Include="fcs\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)fcs\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)tests\projects\Sample_NETCoreSDK_FSharp_Library_netstandard2_0\Sample_NETCoreSDK_FSharp_Library_netstandard2_0.fsproj" />
+      <Projects Include="$(MSBuildThisFileDirectory)fcs\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj" />
     </ItemGroup>
 
     <ItemGroup Condition="'$(TestIDE)' == 'true' OR '$(_RunningRestore)' == 'true'">
-      <Projects Include="vsintegration\fsharp-vsintegration-unittests-build.proj" />
+      <Projects Include="$(MSBuildThisFileDirectory)vsintegration\fsharp-vsintegration-unittests-build.proj" />
     </ItemGroup>
 
   </Target>
@@ -116,24 +151,20 @@
   </Target>
 
   <Target Name="Build" DependsOnTargets="CollectProjects">
-    <ItemGroup>
-      <Projects Include="@(NugetProjects)" />
-    </ItemGroup>
-
-    <MSBuild Projects="@(Projects)" Targets="Build" Properties="Configuration=$(Configuration);BUILD_PUBLICSIGN=$(BUILD_PUBLICSIGN);$(CustomProps)" />
+    <MSBuild Projects="@(Projects);@(NugetProjects)" Targets="Build" Properties="Configuration=$(Configuration);BUILD_PUBLICSIGN=$(BUILD_PUBLICSIGN);$(CustomProps)" />
     <MSBuild Projects="@(NugetProjects)" Targets="Pack" Properties="Configuration=$(Configuration);BUILD_PUBLICSIGN=$(BUILD_PUBLICSIGN);$(CustomProps)" />
   </Target>
 
   <Target Name="Rebuild" DependsOnTargets="CollectProjects">
-    <MSBuild Projects="@(Projects)" Targets="Rebuild" Properties="Configuration=$(Configuration);BUILD_PUBLICSIGN=$(BUILD_PUBLICSIGN);$(CustomProps)" />
+    <MSBuild Projects="@(Projects);@(NugetProjects)" Targets="Rebuild" Properties="Configuration=$(Configuration);BUILD_PUBLICSIGN=$(BUILD_PUBLICSIGN);$(CustomProps)" />
   </Target>
 
   <Target Name="Clean" DependsOnTargets="CollectProjects">
-    <MSBuild Projects="@(Projects)" Targets="Clean" Properties="Configuration=$(Configuration);BUILD_PUBLICSIGN=$(BUILD_PUBLICSIGN);$(CustomProps)" />
+    <MSBuild Projects="@(Projects);@(NugetProjects)" Targets="Clean" Properties="Configuration=$(Configuration);BUILD_PUBLICSIGN=$(BUILD_PUBLICSIGN);$(CustomProps)" />
   </Target>
 
   <Target Name="Restore" DependsOnTargets="_BeforeRestore;CollectProjects">
-    <MSBuild Projects="@(Projects)" Targets="Restore" Properties="Configuration=$(Configuration);BUILD_PUBLICSIGN=$(BUILD_PUBLICSIGN);$(CustomProps)" />
+    <MSBuild Projects="@(Projects);@(NugetProjects)" Targets="Restore" Properties="Configuration=$(Configuration);BUILD_PUBLICSIGN=$(BUILD_PUBLICSIGN);$(CustomProps)" />
   </Target>
 
 </Project>
diff --git a/init-tools.cmd b/init-tools.cmd
index 2c1b6d60bdb..cbdeb27afef 100644
--- a/init-tools.cmd
+++ b/init-tools.cmd
@@ -2,7 +2,7 @@
 setlocal enabledelayedexpansion
 
 set /p DOTNET_TOOLS_VERSION=<"%~dp0DotnetCLIToolsVersion.txt"
-set DOTNET_TOOLS_PATH=%~dp0Tools\dotnet20
+set DOTNET_TOOLS_PATH=%~dp0artifacts\toolset\dotnet
 set dotnetexe=%DOTNET_TOOLS_PATH%\dotnet.exe
 set sdksentinel=%DOTNET_TOOLS_PATH%\sdk-version.txt
 
diff --git a/proto.proj b/proto.proj
index 96f223470ec..443d7015fb5 100644
--- a/proto.proj
+++ b/proto.proj
@@ -7,8 +7,14 @@
 
   <ItemGroup>
     <Projects Include="src\buildtools\buildtools.proj" />
-    <Projects Include="src\fsharp\FSharp.Build\FSharp.Build.fsproj" />
-    <Projects Include="src\fsharp\Fsc\Fsc.fsproj" />
+    <Projects Include="src\fsharp\FSharp.Build\FSharp.Build.fsproj">
+      <AdditionalProperties Condition="'$(OS)' != 'Unix'">TargetFramework=net472</AdditionalProperties>
+      <AdditionalProperties Condition="'$(OS)' == 'Unix'">TargetFramework=netcoreapp2.1</AdditionalProperties>
+    </Projects>
+    <Projects Include="src\fsharp\fsc\fsc.fsproj">
+      <AdditionalProperties Condition="'$(OS)' != 'Unix'">TargetFramework=net472</AdditionalProperties>
+      <AdditionalProperties Condition="'$(OS)' == 'Unix'">TargetFramework=netcoreapp2.1</AdditionalProperties>
+    </Projects>
   </ItemGroup>
 
   <Target Name="Build">
diff --git a/setup/Directory.Build.props b/setup/Directory.Build.props
index 64b72eafc9f..bd233e75785 100644
--- a/setup/Directory.Build.props
+++ b/setup/Directory.Build.props
@@ -1,12 +1,21 @@
 <Project>
 
   <Import Project="$([MSBuild]::GetPathOfFileAbove('FSharp.Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
-  <Import Project="$(NuGetPackageRoot)\MicroBuild.Core\$(MicroBuildCorePackageVersion)\build\MicroBuild.Core.props" />
-  <Import Project="FSharp.Setup.props" />
+  <Import Project="Localization.props" />
 
   <PropertyGroup>
     <DisableOutputPathCopying>true</DisableOutputPathCopying>
     <EnableXlfLocalization>false</EnableXlfLocalization>
+    <SetupRootFolder>$(MSBuildThisFileDirectory)</SetupRootFolder>
+    <SetupResourcesDirectory>$(SetupRootFolder)resources</SetupResourcesDirectory>
+    <BinariesDir>$(SetupRootFolder)..\artifacts\bin</BinariesDir>
+    <OutputPath>$(ArtifactsDir)\VSSetup\$(Configuration)</OutputPath>
+    <IntermediateOutputPath>$(ArtifactsDir)\VSSetup.obj\$(Configuration)\$(MSBuildProjectName)</IntermediateOutputPath>
+    <VsixBuildLocation>$(SetupRootFolder)..\artifacts\VSSetup\$(Configuration)</VsixBuildLocation>
+    <InsertionDir>$(SetupRootFolder)..\artifacts\VSSetup\$(Configuration)\Insertion</InsertionDir>
+
+    <!-- FSharpPackageVersion should be {VS version}.{today's date}.{build number}. Example: 15.6.20160901.3 -->
+    <FSharpPackageVersion>$(VSMajorVersion).$(VSMinorVersion).$(BUILD_BUILDNUMBER)</FSharpPackageVersion>
   </PropertyGroup>
 
 </Project>
diff --git a/setup/Directory.Build.targets b/setup/Directory.Build.targets
index 0619a12001e..ccd47cc0a9a 100644
--- a/setup/Directory.Build.targets
+++ b/setup/Directory.Build.targets
@@ -1,4 +1,3 @@
 <Project>
   <Import Project="$([MSBuild]::GetPathOfFileAbove('FSharp.Directory.Build.targets', '$(MSBuildThisFileDirectory)../'))" />
-  <Import Project="$(NuGetPackageRoot)\MicroBuild.Core\$(MicroBuildCorePackageVersion)\build\MicroBuild.Core.targets" />
 </Project>
diff --git a/setup/FSharp.Setup.props b/setup/FSharp.Setup.props
deleted file mode 100644
index 25398779040..00000000000
--- a/setup/FSharp.Setup.props
+++ /dev/null
@@ -1,142 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information. -->
-<Project>
-    <PropertyGroup>
-        <SetupRootFolder>$(MSBuildThisFileDirectory)</SetupRootFolder>
-    </PropertyGroup>
-
-    <PropertyGroup>
-        <!-- FSharpPackageVersion should be {VS version}.{today's date}.{build number}. Example: 15.6.20160901.3 -->
-        <FSharpPackageVersion>$(VSMajorVersion).$(VSMinorVersion).$(BUILD_BUILDNUMBER)</FSharpPackageVersion>
-    </PropertyGroup>
-
-    <PropertyGroup>
-        <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
-        <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
-    </PropertyGroup>
-
-    <PropertyGroup>
-        <BinariesDir>$(SetupRootFolder)\..\$(Configuration)</BinariesDir>
-        <VsixBuildLocation>$(BinariesDir)\net40\bin\</VsixBuildLocation>
-        <InsertionDir>$(BinariesDir)\insertion</InsertionDir>
-        <IntermediateOutputPath>obj\$(Configuration)\</IntermediateOutputPath>
-        <OutputPath Condition="'$(Lang)' == ''">$(BinariesDir)\setup</OutputPath>
-        <OutputPath Condition="'$(Lang)' != ''">$(BinariesDir)\setup\$(Lang)</OutputPath>
-    </PropertyGroup>
-
-    <ItemGroup>
-        <SetupLanguages Include="ENU">
-            <LocaleCode>ENU</LocaleCode>
-            <LocaleId>1033</LocaleId>
-            <LocaleParentId>9</LocaleParentId>
-            <LocaleParentCulture>en</LocaleParentCulture>
-            <LocaleSpecificCulture>en-US</LocaleSpecificCulture>
-            <IsLangPack>false</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="CHT">
-            <LocaleCode>CHT</LocaleCode>
-            <LocaleId>1028</LocaleId>
-            <LocaleParentId>31748</LocaleParentId>
-            <LocaleParentCulture>zh-Hant</LocaleParentCulture>
-            <LocaleSpecificCulture>zh-TW</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="CSY">
-            <LocaleCode>CSY</LocaleCode>
-            <LocaleId>1029</LocaleId>
-            <LocaleParentId>5</LocaleParentId>
-            <LocaleParentCulture>cs</LocaleParentCulture>
-            <LocaleSpecificCulture>cs-CZ</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="DEU">
-            <LocaleCode>DEU</LocaleCode>
-            <LocaleId>1031</LocaleId>
-            <LocaleParentId>7</LocaleParentId>
-            <LocaleParentCulture>de</LocaleParentCulture>
-            <LocaleSpecificCulture>de-DE</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="FRA">
-            <LocaleCode>FRA</LocaleCode>
-            <LocaleId>1036</LocaleId>
-            <LocaleParentId>12</LocaleParentId>
-            <LocaleParentCulture>fr</LocaleParentCulture>
-            <LocaleSpecificCulture>fr-FR</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="ITA">
-            <LocaleCode>ITA</LocaleCode>
-            <LocaleId>1040</LocaleId>
-            <LocaleParentId>16</LocaleParentId>
-            <LocaleParentCulture>it</LocaleParentCulture>
-            <LocaleSpecificCulture>it-IT</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="JPN">
-            <LocaleCode>JPN</LocaleCode>
-            <LocaleId>1041</LocaleId>
-            <LocaleParentId>17</LocaleParentId>
-            <LocaleParentCulture>ja</LocaleParentCulture>
-            <LocaleSpecificCulture>ja-JP</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="KOR">
-            <LocaleCode>KOR</LocaleCode>
-            <LocaleId>1042</LocaleId>
-            <LocaleParentId>18</LocaleParentId>
-            <LocaleParentCulture>ko</LocaleParentCulture>
-            <LocaleSpecificCulture>ko-KR</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="PLK">
-            <LocaleCode>PLK</LocaleCode>
-            <LocaleId>1045</LocaleId>
-            <LocaleParentId>21</LocaleParentId>
-            <LocaleParentCulture>pl</LocaleParentCulture>
-            <LocaleSpecificCulture>pl-PL</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="PTB">
-            <LocaleCode>PTB</LocaleCode>
-            <LocaleId>1046</LocaleId>
-            <LocaleParentId>1046</LocaleParentId>
-            <LocaleParentCulture>pt-BR</LocaleParentCulture>
-            <LocaleSpecificCulture>pt-BR</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="RUS">
-            <LocaleCode>RUS</LocaleCode>
-            <LocaleId>1049</LocaleId>
-            <LocaleParentId>25</LocaleParentId>
-            <LocaleParentCulture>ru</LocaleParentCulture>
-            <LocaleSpecificCulture>ru-RU</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="TRK">
-            <LocaleCode>TRK</LocaleCode>
-            <LocaleId>1055</LocaleId>
-            <LocaleParentId>31</LocaleParentId>
-            <LocaleParentCulture>tr</LocaleParentCulture>
-            <LocaleSpecificCulture>tr-TR</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="CHS">
-            <LocaleCode>CHS</LocaleCode>
-            <LocaleId>2052</LocaleId>
-            <LocaleParentId>4</LocaleParentId>
-            <LocaleParentCulture>zh-Hans</LocaleParentCulture>
-            <LocaleSpecificCulture>zh-CN</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-        <SetupLanguages Include="ESN">
-            <LocaleCode>ESN</LocaleCode>
-            <LocaleId>3082</LocaleId>
-            <LocaleParentId>10</LocaleParentId>
-            <LocaleParentCulture>es</LocaleParentCulture>
-            <LocaleSpecificCulture>es-ES</LocaleSpecificCulture>
-            <IsLangPack>true</IsLangPack>
-        </SetupLanguages>
-    </ItemGroup>
-
-</Project>
diff --git a/setup/Localization.props b/setup/Localization.props
new file mode 100644
index 00000000000..37c13afcd2c
--- /dev/null
+++ b/setup/Localization.props
@@ -0,0 +1,120 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information. -->
+<Project>
+
+  <ItemGroup>
+    <SetupLanguages Include="ENU">
+      <LocaleCode>ENU</LocaleCode>
+      <LocaleId>1033</LocaleId>
+      <LocaleParentId>9</LocaleParentId>
+      <LocaleParentCulture>en</LocaleParentCulture>
+      <LocaleSpecificCulture>en-US</LocaleSpecificCulture>
+      <IsLangPack>false</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="CHT">
+      <LocaleCode>CHT</LocaleCode>
+      <LocaleId>1028</LocaleId>
+      <LocaleParentId>31748</LocaleParentId>
+      <LocaleParentCulture>zh-Hant</LocaleParentCulture>
+      <LocaleSpecificCulture>zh-TW</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="CSY">
+      <LocaleCode>CSY</LocaleCode>
+      <LocaleId>1029</LocaleId>
+      <LocaleParentId>5</LocaleParentId>
+      <LocaleParentCulture>cs</LocaleParentCulture>
+      <LocaleSpecificCulture>cs-CZ</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="DEU">
+      <LocaleCode>DEU</LocaleCode>
+      <LocaleId>1031</LocaleId>
+      <LocaleParentId>7</LocaleParentId>
+      <LocaleParentCulture>de</LocaleParentCulture>
+      <LocaleSpecificCulture>de-DE</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="FRA">
+      <LocaleCode>FRA</LocaleCode>
+      <LocaleId>1036</LocaleId>
+      <LocaleParentId>12</LocaleParentId>
+      <LocaleParentCulture>fr</LocaleParentCulture>
+      <LocaleSpecificCulture>fr-FR</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="ITA">
+      <LocaleCode>ITA</LocaleCode>
+      <LocaleId>1040</LocaleId>
+      <LocaleParentId>16</LocaleParentId>
+      <LocaleParentCulture>it</LocaleParentCulture>
+      <LocaleSpecificCulture>it-IT</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="JPN">
+      <LocaleCode>JPN</LocaleCode>
+      <LocaleId>1041</LocaleId>
+      <LocaleParentId>17</LocaleParentId>
+      <LocaleParentCulture>ja</LocaleParentCulture>
+      <LocaleSpecificCulture>ja-JP</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="KOR">
+      <LocaleCode>KOR</LocaleCode>
+      <LocaleId>1042</LocaleId>
+      <LocaleParentId>18</LocaleParentId>
+      <LocaleParentCulture>ko</LocaleParentCulture>
+      <LocaleSpecificCulture>ko-KR</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="PLK">
+      <LocaleCode>PLK</LocaleCode>
+      <LocaleId>1045</LocaleId>
+      <LocaleParentId>21</LocaleParentId>
+      <LocaleParentCulture>pl</LocaleParentCulture>
+      <LocaleSpecificCulture>pl-PL</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="PTB">
+      <LocaleCode>PTB</LocaleCode>
+      <LocaleId>1046</LocaleId>
+      <LocaleParentId>1046</LocaleParentId>
+      <LocaleParentCulture>pt-BR</LocaleParentCulture>
+      <LocaleSpecificCulture>pt-BR</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="RUS">
+      <LocaleCode>RUS</LocaleCode>
+      <LocaleId>1049</LocaleId>
+      <LocaleParentId>25</LocaleParentId>
+      <LocaleParentCulture>ru</LocaleParentCulture>
+      <LocaleSpecificCulture>ru-RU</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="TRK">
+      <LocaleCode>TRK</LocaleCode>
+      <LocaleId>1055</LocaleId>
+      <LocaleParentId>31</LocaleParentId>
+      <LocaleParentCulture>tr</LocaleParentCulture>
+      <LocaleSpecificCulture>tr-TR</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="CHS">
+      <LocaleCode>CHS</LocaleCode>
+      <LocaleId>2052</LocaleId>
+      <LocaleParentId>4</LocaleParentId>
+      <LocaleParentCulture>zh-Hans</LocaleParentCulture>
+      <LocaleSpecificCulture>zh-CN</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+    <SetupLanguages Include="ESN">
+      <LocaleCode>ESN</LocaleCode>
+      <LocaleId>3082</LocaleId>
+      <LocaleParentId>10</LocaleParentId>
+      <LocaleParentCulture>es</LocaleParentCulture>
+      <LocaleSpecificCulture>es-ES</LocaleSpecificCulture>
+      <IsLangPack>true</IsLangPack>
+    </SetupLanguages>
+  </ItemGroup>
+
+</Project>
diff --git a/setup/Swix/Directory.Build.props b/setup/Swix/Directory.Build.props
index 92203d4e217..f64df1d29de 100644
--- a/setup/Swix/Directory.Build.props
+++ b/setup/Swix/Directory.Build.props
@@ -1,14 +1,14 @@
 <Project>
   <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
+  <Import Project="$(NuGetPackageRoot)\MicroBuild.Core\$(MicroBuildCorePackageVersion)\build\MicroBuild.Core.props" />
 
   <PropertyGroup>
+    <Configuration Condition="'$(Configuration)' == ''">Debug</Configuration>
     <OutputArchitecture>neutral</OutputArchitecture>
     <OutputLocalized>false</OutputLocalized>
     <OutputType>vsix</OutputType>
     <IsPackage>true</IsPackage>
-    <BinariesFolder>$(FSharpSourcesRoot)\..\$(Configuration)</BinariesFolder>
-    <OutputPath>$(BinariesFolder)\insertion</OutputPath>
-    <IntermediateOutputPath>$(MSBuildProjectDirectory)\obj</IntermediateOutputPath>
+    <BinariesFolder>$(ArtifactsBinDir)</BinariesFolder>
   </PropertyGroup>
 
 </Project>
diff --git a/setup/Swix/Directory.Build.targets b/setup/Swix/Directory.Build.targets
index 14437118703..974c6da4f1b 100644
--- a/setup/Swix/Directory.Build.targets
+++ b/setup/Swix/Directory.Build.targets
@@ -1,3 +1,10 @@
 <Project>
+
+  <PropertyGroup>
+    <!-- for everything else, $(PackageOutputPath) is interpreted as a directory, but for the SWIX toolset a file name -->
+    <PackageOutputPath>$(ArtifactsDir)\VSSetup\$(Configuration)\Insertion\$(OutputName).vsix</PackageOutputPath>
+  </PropertyGroup>
+
   <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.targets', '$(MSBuildThisFileDirectory)../'))" />
+  <Import Project="$(NuGetPackageRoot)\MicroBuild.Core\$(MicroBuildCorePackageVersion)\build\MicroBuild.Core.targets" />
 </Project>
diff --git a/setup/Swix/Microsoft.FSharp.Compiler.Resources/Files.swr b/setup/Swix/Microsoft.FSharp.Compiler.Resources/Files.swr
index 464fdd774ee..9fed4387c96 100644
--- a/setup/Swix/Microsoft.FSharp.Compiler.Resources/Files.swr
+++ b/setup/Swix/Microsoft.FSharp.Compiler.Resources/Files.swr
@@ -5,7 +5,7 @@ package name=Microsoft.FSharp.Compiler.Resources
         vs.package.language=$(LocaleSpecificCulture)
 
 folder "InstallDir:Common7\IDE\CommonExtensions\Microsoft\FSharpCompiler\$(LocaleParentCulture)"
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.Build.resources.dll"
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.Compiler.Interactive.Settings.resources.dll"
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.Compiler.Private.resources.dll"
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.Core.resources.dll"
+  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\net472\$(LocaleParentCulture)\FSharp.Build.resources.dll"
+  file source="$(BinariesFolder)\FSharp.Compiler.Interactive.Settings\$(Configuration)\net472\$(LocaleParentCulture)\FSharp.Compiler.Interactive.Settings.resources.dll"
+  file source="$(BinariesFolder)\FSharp.Compiler.Private\$(Configuration)\net472\$(LocaleParentCulture)\FSharp.Compiler.Private.resources.dll"
+  file source="$(BinariesFolder)\FSharp.Core\$(Configuration)\net45\$(LocaleParentCulture)\FSharp.Core.resources.dll"
diff --git a/setup/Swix/Microsoft.FSharp.Compiler.Resources/Microsoft.FSharp.Compiler.Resources.swixproj b/setup/Swix/Microsoft.FSharp.Compiler.Resources/Microsoft.FSharp.Compiler.Resources.swixproj
index 166cbb2d519..ac8e74d4854 100644
--- a/setup/Swix/Microsoft.FSharp.Compiler.Resources/Microsoft.FSharp.Compiler.Resources.swixproj
+++ b/setup/Swix/Microsoft.FSharp.Compiler.Resources/Microsoft.FSharp.Compiler.Resources.swixproj
@@ -10,6 +10,7 @@
 
   <PropertyGroup>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);BinariesFolder=$(BinariesFolder)</PackagePreprocessorDefinitions>
+    <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);Configuration=$(Configuration)</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);FSharpPackageVersion=$(FSharpPackageVersion)</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);LocaleParentCulture=$(LocaleParentCulture)</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);LocaleSpecificCulture=$(LocaleSpecificCulture)</PackagePreprocessorDefinitions>
diff --git a/setup/Swix/Microsoft.FSharp.Compiler/Files.swr b/setup/Swix/Microsoft.FSharp.Compiler/Files.swr
index ad63ffe3c2c..f378338eef8 100644
--- a/setup/Swix/Microsoft.FSharp.Compiler/Files.swr
+++ b/setup/Swix/Microsoft.FSharp.Compiler/Files.swr
@@ -5,34 +5,34 @@ package name=Microsoft.FSharp.Compiler
 
 folder "InstallDir:Common7\IDE\CommonExtensions\Microsoft\FSharp"
 
-  file source=$(BinariesFolder)\net40\bin\fsc.exe vs.file.ngen=yes vs.file.ngenArchitecture=All vs.file.ngenPriority=2 vs.file.ngenApplication="[installDir]\Common7\IDE\CommonExtensions\Microsoft\FSharp\fsc.exe"
-  file source="$(BinariesFolder)\net40\bin\fsc.exe.config"
+  file source=$(BinariesFolder)\fsc\$(Configuration)\net472\fsc.exe vs.file.ngen=yes vs.file.ngenArchitecture=All vs.file.ngenPriority=2 vs.file.ngenApplication="[installDir]\Common7\IDE\CommonExtensions\Microsoft\FSharp\fsc.exe"
+  file source="$(BinariesFolder)\fsc\$(Configuration)\net472\fsc.exe.config"
 
-  file source=$(BinariesFolder)\net40\bin\fsi.exe vs.file.ngen=yes vs.file.ngenArchitecture=X86 vs.file.ngenPriority=2 vs.file.ngenApplication="[installDir]\Common7\IDE\CommonExtensions\Microsoft\FSharp\fsi.exe"
-  file source="$(BinariesFolder)\net40\bin\fsi.exe.config"
+  file source=$(BinariesFolder)\fsi\$(Configuration)\net472\fsi.exe vs.file.ngen=yes vs.file.ngenArchitecture=X86 vs.file.ngenPriority=2 vs.file.ngenApplication="[installDir]\Common7\IDE\CommonExtensions\Microsoft\FSharp\fsi.exe"
+  file source="$(BinariesFolder)\fsi\$(Configuration)\net472\fsi.exe.config"
 
-  file source="$(BinariesFolder)\net40\bin\fsiAnyCpu.exe" vs.file.ngen=yes vs.file.ngenArchitecture=X64 vs.file.ngenPriority=2 vs.file.ngenApplication="[installDir]\Common7\IDE\CommonExtensions\Microsoft\FSharp\fsiAnyCpu.exe"
-  file source="$(BinariesFolder)\net40\bin\fsiAnyCpu.exe.config"
+  file source="$(BinariesFolder)\fsiAnyCpu\$(Configuration)\net472\fsiAnyCpu.exe" vs.file.ngen=yes vs.file.ngenArchitecture=X64 vs.file.ngenPriority=2 vs.file.ngenApplication="[installDir]\Common7\IDE\CommonExtensions\Microsoft\FSharp\fsiAnyCpu.exe"
+  file source="$(BinariesFolder)\fsiAnyCpu\$(Configuration)\net472\fsiAnyCpu.exe.config"
 
-  file source="$(BinariesFolder)\net40\bin\FSharp.Compiler.Interactive.Settings.dll" vs.file.ngen=yes vs.file.ngenArchitecture=All vs.file.ngenPriority=2
-  file source="$(BinariesFolder)\net40\bin\FSharp.Compiler.Private.dll" vs.file.ngen=yes vs.file.ngenArchitecture=All vs.file.ngenPriority=2
-  file source="$(BinariesFolder)\net40\bin\FSharp.Compiler.Server.Shared.dll" vs.file.ngen=yes vs.file.ngenArchitecture=All vs.file.ngenPriority=2
+  file source="$(BinariesFolder)\FSharp.Compiler.Interactive.Settings\$(Configuration)\net472\FSharp.Compiler.Interactive.Settings.dll" vs.file.ngen=yes vs.file.ngenArchitecture=All vs.file.ngenPriority=2
+  file source="$(BinariesFolder)\FSharp.Compiler.Private\$(Configuration)\net472\FSharp.Compiler.Private.dll" vs.file.ngen=yes vs.file.ngenArchitecture=All vs.file.ngenPriority=2
+  file source="$(BinariesFolder)\FSharp.Compiler.Server.Shared\$(Configuration)\net472\FSharp.Compiler.Server.Shared.dll" vs.file.ngen=yes vs.file.ngenArchitecture=All vs.file.ngenPriority=2
 
-  file source="$(BinariesFolder)\net40\bin\FSharp.Core.dll" vs.file.ngen=yes vs.file.ngenArchitecture=All vs.file.ngenPriority=2
-  file source="$(BinariesFolder)\net40\bin\FSharp.Core.optdata"
-  file source="$(BinariesFolder)\net40\bin\FSharp.Core.sigdata"
+  file source="$(BinariesFolder)\FSharp.Core\$(Configuration)\net45\FSharp.Core.dll" vs.file.ngen=yes vs.file.ngenArchitecture=All vs.file.ngenPriority=2
+  file source="$(BinariesFolder)\FSharp.Core\$(Configuration)\net45\FSharp.Core.optdata"
+  file source="$(BinariesFolder)\FSharp.Core\$(Configuration)\net45\FSharp.Core.sigdata"
 
-  file source="$(BinariesFolder)\net40\bin\FSharp.Build.dll" vs.file.ngen=yes vs.file.ngenArchitecture=All vs.file.ngenPriority=2
+  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\net472\FSharp.Build.dll" vs.file.ngen=yes vs.file.ngenArchitecture=All vs.file.ngenPriority=2
 
   file source="$(PackagesFolder)\Microsoft.VisualFSharp.Type.Providers.Redist\$(MicrosoftVisualFSharpTypeProvidersRedistPackageVersion)\content\4.3.0.0\FSharp.Data.TypeProviders.dll"
-  file source="$(BinariesFolder)\net40\bin\Microsoft.Build.dll"
-  file source="$(BinariesFolder)\net40\bin\Microsoft.Build.Framework.dll"
-  file source="$(BinariesFolder)\net40\bin\Microsoft.Build.Tasks.Core.dll"
-  file source="$(BinariesFolder)\net40\bin\Microsoft.Build.Utilities.Core.dll"
-  file source="$(BinariesFolder)\net40\bin\Microsoft.Portable.FSharp.Targets"
-  file source="$(BinariesFolder)\net40\bin\System.Collections.Immutable.dll"
-  file source="$(BinariesFolder)\net40\bin\System.Reflection.Metadata.dll"
-  file source="$(BinariesFolder)\net40\bin\Microsoft.FSharp.NetSdk.props"
-  file source="$(BinariesFolder)\net40\bin\Microsoft.FSharp.NetSdk.targets"
-  file source="$(BinariesFolder)\net40\bin\Microsoft.FSharp.Overrides.NetSdk.targets"
-  file source="$(BinariesFolder)\net40\bin\Microsoft.FSharp.Targets"
+  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\net472\Microsoft.Build.dll"
+  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\net472\Microsoft.Build.Framework.dll"
+  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\net472\Microsoft.Build.Tasks.Core.dll"
+  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\net472\Microsoft.Build.Utilities.Core.dll"
+  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\net472\Microsoft.Portable.FSharp.Targets"
+  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\net472\System.Collections.Immutable.dll"
+  file source="$(BinariesFolder)\FSharp.Compiler.Private\$(Configuration)\net472\System.Reflection.Metadata.dll"
+  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\net472\Microsoft.FSharp.NetSdk.props"
+  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\net472\Microsoft.FSharp.NetSdk.targets"
+  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\net472\Microsoft.FSharp.Overrides.NetSdk.targets"
+  file source="$(BinariesFolder)\FSharp.Build\$(Configuration)\net472\Microsoft.FSharp.Targets"
diff --git a/setup/Swix/Microsoft.FSharp.Compiler/Microsoft.FSharp.Compiler.swixproj b/setup/Swix/Microsoft.FSharp.Compiler/Microsoft.FSharp.Compiler.swixproj
index 955da213a71..f256dd46779 100644
--- a/setup/Swix/Microsoft.FSharp.Compiler/Microsoft.FSharp.Compiler.swixproj
+++ b/setup/Swix/Microsoft.FSharp.Compiler/Microsoft.FSharp.Compiler.swixproj
@@ -10,6 +10,7 @@
 
   <PropertyGroup>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);BinariesFolder=$(BinariesFolder)</PackagePreprocessorDefinitions>
+    <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);Configuration=$(Configuration)</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);PackagesFolder=$(NuGetPackageRoot)</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);FSharpTreeRoot=$(FSharpTreeRoot)</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);FSharpPackageVersion=$(FSharpPackageVersion)</PackagePreprocessorDefinitions>
diff --git a/setup/Swix/Microsoft.FSharp.Dependencies/Files.swr b/setup/Swix/Microsoft.FSharp.Dependencies/Files.swr
index 6ded7ba325f..f927497e193 100644
--- a/setup/Swix/Microsoft.FSharp.Dependencies/Files.swr
+++ b/setup/Swix/Microsoft.FSharp.Dependencies/Files.swr
@@ -4,16 +4,11 @@ package name=Microsoft.FSharp.Dependencies
         version=$(FSharpPackageVersion)
 
 folder "InstallDir:MSBuild\Microsoft\VisualStudio\v$(VSGeneralVersion)\FSharp"
-  file "Microsoft.FSharp.targets" source="$(BinariesFolder)\setup\$(TargetFramework)\resources\Microsoft.FSharp.Shim.targets"
-  file "Microsoft.Portable.FSharp.targets" source="$(BinariesFolder)\setup\$(TargetFramework)\resources\Microsoft.Portable.FSharp.Shim.targets"
-  file "Microsoft.FSharp.NetSdk.targets" source="$(BinariesFolder)\setup\$(TargetFramework)\resources\Microsoft.FSharp.NetSdk.Shim.targets"
-  file "Microsoft.FSharp.Overrides.NetSdk.targets" source="$(BinariesFolder)\setup\$(TargetFramework)\resources\Microsoft.FSharp.Overrides.NetSdk.Shim.targets"
-  file "Microsoft.FSharp.NetSdk.props" source="$(BinariesFolder)\setup\$(TargetFramework)\resources\Microsoft.FSharp.NetSdk.Shim.props"
-
-folder "InstallDir:Common7\IDE\PublicAssemblies"
-  file source="$(BinariesFolder)\net40\bin\FSharp.Core.dll" vs.file.ngen=yes
-  file source="$(BinariesFolder)\net40\bin\FSharp.Core.optdata"
-  file source="$(BinariesFolder)\net40\bin\FSharp.Core.sigdata"
+  file "Microsoft.FSharp.targets" source="$(SetupShimsDir)\Microsoft.FSharp.Shim.targets"
+  file "Microsoft.Portable.FSharp.targets" source="$(SetupShimsDir)\Microsoft.Portable.FSharp.Shim.targets"
+  file "Microsoft.FSharp.NetSdk.targets" source="$(SetupShimsDir)\Microsoft.FSharp.NetSdk.Shim.targets"
+  file "Microsoft.FSharp.Overrides.NetSdk.targets" source="$(SetupShimsDir)\Microsoft.FSharp.Overrides.NetSdk.Shim.targets"
+  file "Microsoft.FSharp.NetSdk.props" source="$(SetupShimsDir)\Microsoft.FSharp.NetSdk.Shim.props"
 
 folder "InstallDir:Common7\Tools\VsDevCmd\Ext"
   file source="fsharp.bat"
diff --git a/setup/Swix/Microsoft.FSharp.Dependencies/Microsoft.FSharp.Dependencies.swixproj b/setup/Swix/Microsoft.FSharp.Dependencies/Microsoft.FSharp.Dependencies.swixproj
index dd1452bbefc..e30eaaf0fe1 100644
--- a/setup/Swix/Microsoft.FSharp.Dependencies/Microsoft.FSharp.Dependencies.swixproj
+++ b/setup/Swix/Microsoft.FSharp.Dependencies/Microsoft.FSharp.Dependencies.swixproj
@@ -10,7 +10,9 @@
 
   <PropertyGroup>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);BinariesFolder=$(BinariesFolder)</PackagePreprocessorDefinitions>
+    <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);Configuration=$(Configuration)</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);FSharpPackageVersion=$(FSharpPackageVersion)</PackagePreprocessorDefinitions>
+    <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);SetupShimsDir=$(MSBuildThisFileDirectory)..\..\shims</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);TargetFramework=$(TargetFramework)</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);VSGeneralVersion=$(VSGeneralVersion)</PackagePreprocessorDefinitions>
   </PropertyGroup>
diff --git a/setup/Swix/Microsoft.FSharp.IDE/Files.swr b/setup/Swix/Microsoft.FSharp.IDE/Files.swr
index 0d47c502090..2e0ee2bcf3b 100644
--- a/setup/Swix/Microsoft.FSharp.IDE/Files.swr
+++ b/setup/Swix/Microsoft.FSharp.IDE/Files.swr
@@ -4,10 +4,10 @@ package name=Microsoft.FSharp.IDE
         version=$(FSharpPackageVersion)
 
 folder "InstallDir:Common7\IDE\NewScriptItems"
-  file source="$(BinariesFolder)\setup\$(TargetFramework)\resources\NewFileDialog\Script\NewFSharpScriptItems.vsdir"
-  file source="$(BinariesFolder)\setup\$(TargetFramework)\resources\NewFileDialog\Script\Script.fsx"
+  file source="$(SetupResourcesDir)\NewFileDialog\Script\NewFSharpScriptItems.vsdir"
+  file source="$(SetupResourcesDir)\NewFileDialog\Script\Script.fsx"
 
 folder "InstallDir:Common7\IDE\NewFileItems"
-  file source="$(BinariesFolder)\setup\$(TargetFramework)\resources\NewFileDialog\General\NewFSharpFileItems.vsdir"
-  file source="$(BinariesFolder)\setup\$(TargetFramework)\resources\NewFileDialog\General\File.fs"
-  file source="$(BinariesFolder)\setup\$(TargetFramework)\resources\NewFileDialog\General\Script.fsx"
+  file source="$(SetupResourcesDir)\NewFileDialog\General\NewFSharpFileItems.vsdir"
+  file source="$(SetupResourcesDir)\NewFileDialog\General\File.fs"
+  file source="$(SetupResourcesDir)\NewFileDialog\General\Script.fsx"
diff --git a/setup/Swix/Microsoft.FSharp.IDE/Microsoft.FSharp.IDE.swixproj b/setup/Swix/Microsoft.FSharp.IDE/Microsoft.FSharp.IDE.swixproj
index b26924e23c2..223a7262fcb 100644
--- a/setup/Swix/Microsoft.FSharp.IDE/Microsoft.FSharp.IDE.swixproj
+++ b/setup/Swix/Microsoft.FSharp.IDE/Microsoft.FSharp.IDE.swixproj
@@ -9,8 +9,8 @@
   </PropertyGroup>
 
   <PropertyGroup>
-    <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);BinariesFolder=$(BinariesFolder)</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);FSharpPackageVersion=$(FSharpPackageVersion)</PackagePreprocessorDefinitions>
+    <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);SetupResourcesDir=$(MSBuildThisFileDirectory)..\..\resources</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);TargetFramework=$(TargetFramework)</PackagePreprocessorDefinitions>
   </PropertyGroup>
 
diff --git a/setup/Swix/Microsoft.FSharp.Vsix.Resources/Files.swr b/setup/Swix/Microsoft.FSharp.Vsix.Resources/Files.swr
index a8c5becc80e..61dddfcf048 100644
--- a/setup/Swix/Microsoft.FSharp.Vsix.Resources/Files.swr
+++ b/setup/Swix/Microsoft.FSharp.Vsix.Resources/Files.swr
@@ -5,16 +5,16 @@ package name=Microsoft.FSharp.VSIX.Full.Resources
         vs.package.language=$(LocaleSpecificCulture)
 
 folder "InstallDir:Common7\IDE\PublicAssemblies\$(LocaleParentCulture)"
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.Core.resources.dll" vs.file.ngen=yes
+  file source="$(BinariesFolder)\FSharp.Core\$(Configuration)\net45\$(LocaleParentCulture)\FSharp.Core.resources.dll" vs.file.ngen=yes
 
 folder "InstallDir:Common7\IDE\CommonExtensions\Microsoft\FSharp\$(LocaleParentCulture)"
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.Compiler.Private.resources.dll" vs.file.ngen=yes
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.Core.resources.dll" vs.file.ngen=yes
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.Editor.resources.dll" vs.file.ngen=yes
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.LanguageService.Base.resources.dll" vs.file.ngen=yes
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.LanguageService.resources.dll" vs.file.ngen=yes
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.ProjectSystem.Base.resources.dll" vs.file.ngen=yes
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.ProjectSystem.FSharp.resources.dll" vs.file.ngen=yes
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.ProjectSystem.PropertyPages.resources.dll" vs.file.ngen=yes
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.UIResources.resources.dll" vs.file.ngen=yes
-  file source="$(BinariesFolder)\net40\bin\$(LocaleParentCulture)\FSharp.VS.FSI.resources.dll" vs.file.ngen=yes
+  file source="$(BinariesFolder)\FSharp.Compiler.Private\$(Configuration)\net472\$(LocaleParentCulture)\FSharp.Compiler.Private.resources.dll" vs.file.ngen=yes
+  file source="$(BinariesFolder)\FSharp.Core\$(Configuration)\net45\$(LocaleParentCulture)\FSharp.Core.resources.dll" vs.file.ngen=yes
+  file source="$(BinariesFolder)\FSharp.Editor\$(Configuration)\net472\$(LocaleParentCulture)\FSharp.Editor.resources.dll" vs.file.ngen=yes
+  file source="$(BinariesFolder)\FSharp.LanguageService.Base\$(Configuration)\net472\$(LocaleParentCulture)\FSharp.LanguageService.Base.resources.dll" vs.file.ngen=yes
+  file source="$(BinariesFolder)\FSharp.LanguageService\$(Configuration)\net472\$(LocaleParentCulture)\FSharp.LanguageService.resources.dll" vs.file.ngen=yes
+  file source="$(BinariesFolder)\ProjectSystem.Base\$(Configuration)\net472\$(LocaleParentCulture)\FSharp.ProjectSystem.Base.resources.dll" vs.file.ngen=yes
+  file source="$(BinariesFolder)\ProjectSystem\$(Configuration)\net472\$(LocaleParentCulture)\FSharp.ProjectSystem.FSharp.resources.dll" vs.file.ngen=yes
+  file source="$(BinariesFolder)\FSharp.PropertiesPages\$(Configuration)\net472\$(LocaleParentCulture)\FSharp.ProjectSystem.PropertyPages.resources.dll" vs.file.ngen=yes
+  file source="$(BinariesFolder)\FSharp.UIResources\$(Configuration)\net472\$(LocaleParentCulture)\FSharp.UIResources.resources.dll" vs.file.ngen=yes
+  file source="$(BinariesFolder)\FSharp.VS.FSI\$(Configuration)\net472\$(LocaleParentCulture)\FSharp.VS.FSI.resources.dll" vs.file.ngen=yes
diff --git a/setup/Swix/Microsoft.FSharp.Vsix.Resources/Microsoft.FSharp.Vsix.Resources.swixproj b/setup/Swix/Microsoft.FSharp.Vsix.Resources/Microsoft.FSharp.Vsix.Resources.swixproj
index fd39c147b4c..d8952b40fe7 100644
--- a/setup/Swix/Microsoft.FSharp.Vsix.Resources/Microsoft.FSharp.Vsix.Resources.swixproj
+++ b/setup/Swix/Microsoft.FSharp.Vsix.Resources/Microsoft.FSharp.Vsix.Resources.swixproj
@@ -9,6 +9,7 @@
   </PropertyGroup>
 
   <PropertyGroup>
+    <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);Configuration=$(Configuration)</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);BinariesFolder=$(BinariesFolder)</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);FSharpPackageVersion=$(FSharpPackageVersion)</PackagePreprocessorDefinitions>
     <PackagePreprocessorDefinitions>$(PackagePreprocessorDefinitions);LocaleCode=$(LocaleCode)</PackagePreprocessorDefinitions>
diff --git a/setup/Swix/Microsoft.FSharp.Vsix.Resources/Templates.swr b/setup/Swix/Microsoft.FSharp.Vsix.Resources/Templates.swr
index 770d904e226..5de89f0cadd 100644
--- a/setup/Swix/Microsoft.FSharp.Vsix.Resources/Templates.swr
+++ b/setup/Swix/Microsoft.FSharp.Vsix.Resources/Templates.swr
@@ -6,8 +6,8 @@ package name=Microsoft.FSharp.VSIX.Full.Resources
 
 folder "InstallDir:Common7\IDE\ProjectTemplates\FSharp\$(LocaleId)"
   folder "ConsoleApplication"
-    file source="$(BinariesFolder)\net40\bin\ProjectTemplates\FSharp\$(LocaleParentId)\ConsoleApplication.zip"
+    file source="$(BinariesFolder)\ConsoleProject\$(Configuration)\$(LocaleParentId)\ConsoleApplication.zip"
   folder "Library"
-    file source="$(BinariesFolder)\net40\bin\ProjectTemplates\FSharp\$(LocaleParentId)\Library.zip"
+    file source="$(BinariesFolder)\LibraryProject\$(Configuration)\$(LocaleParentId)\Library.zip"
   folder "Tutorial"
-    file source="$(BinariesFolder)\net40\bin\ProjectTemplates\FSharp\$(LocaleParentId)\Tutorial.zip"
+    file source="$(BinariesFolder)\TutorialProject\$(Configuration)\$(LocaleParentId)\Tutorial.zip"
diff --git a/setup/Swix/Microsoft.FSharp.vsmanproj b/setup/Swix/Microsoft.FSharp.vsmanproj
index d2b0388c272..6e6f7d4e7e9 100644
--- a/setup/Swix/Microsoft.FSharp.vsmanproj
+++ b/setup/Swix/Microsoft.FSharp.vsmanproj
@@ -6,6 +6,7 @@
   <PropertyGroup>
     <FinalizeManifest>true</FinalizeManifest>
     <FinalizeSkipLayout>true</FinalizeSkipLayout>
+    <OutputPath>$(ArtifactsDir)\VSSetup\$(Configuration)\Insertion</OutputPath>
     <InsertionDir>$(OutputPath)</InsertionDir>
     <ManifestBuildVersion>$(FSharpPackageVersion)</ManifestBuildVersion>
   </PropertyGroup>
@@ -23,17 +24,17 @@
 
   <Target Name="IncludeFSharpManifests" DependsOnTargets="CopyInsertionItems">
     <ItemGroup>
-      <MergeManifest Include="$(OutputPath)\Microsoft.FSharp.Compiler.json" />
-      <MergeManifest Include="$(OutputPath)\Microsoft.FSharp.Compiler.Resources.%(SetupLanguages.LocaleCode).json" />
+      <MergeManifest Include="$(InsertionDir)\Microsoft.FSharp.Compiler.json" />
+      <MergeManifest Include="$(InsertionDir)\Microsoft.FSharp.Compiler.Resources.%(SetupLanguages.LocaleCode).json" />
 
-      <MergeManifest Include="$(OutputPath)\Microsoft.FSharp.SDK.json" />
+      <MergeManifest Include="$(InsertionDir)\Microsoft.FSharp.SDK.json" />
 
-      <MergeManifest Include="$(OutputPath)\Microsoft.FSharp.Vsix.Full.Core.json" />
-      <MergeManifest Include="$(OutputPath)\Microsoft.FSharp.Vsix.Full.Resources.%(SetupLanguages.LocaleCode).json" />
+      <MergeManifest Include="$(InsertionDir)\Microsoft.FSharp.Vsix.Full.Core.json" />
+      <MergeManifest Include="$(InsertionDir)\Microsoft.FSharp.Vsix.Full.Resources.%(SetupLanguages.LocaleCode).json" />
 
-      <MergeManifest Include="$(OutputPath)\Microsoft.FSharp.VSIX.Templates.json" />
-      <MergeManifest Include="$(OutputPath)\Microsoft.FSharp.Dependencies.json" />
-      <MergeManifest Include="$(OutputPath)\Microsoft.FSharp.IDE.json" />
+      <MergeManifest Include="$(InsertionDir)\Microsoft.FSharp.VSIX.Templates.json" />
+      <MergeManifest Include="$(InsertionDir)\Microsoft.FSharp.Dependencies.json" />
+      <MergeManifest Include="$(InsertionDir)\Microsoft.FSharp.IDE.json" />
     </ItemGroup>
   </Target>
 
diff --git a/setup/publish-assets.ps1 b/setup/publish-assets.ps1
index 29604698b4c..bfa905bbad9 100644
--- a/setup/publish-assets.ps1
+++ b/setup/publish-assets.ps1
@@ -16,7 +16,8 @@ The API key used to authenticate with MyGet.
 Param(
     [string]$binariesPath = $null,
     [string]$branchName = $null,
-    [string]$apiKey = $null
+    [string]$apiKey = $null,
+    [string]$configuration = $null
 )
 
 Set-StrictMode -Version 2.0
@@ -40,7 +41,7 @@ try {
     }
 
     $branchName = $branchName.Replace("/", "_") # can't have slashes in the branch name
-    $vsix = Join-Path $binariesPath "net40\bin\VisualFSharpFull.vsix"
+    $vsix = Join-Path $binariesPath "VisualFSharpFull\$configuration\net46\VisualFSharpFull.vsix"
 
     Write-Host "  Uploading '$vsix' to '$requestUrl'."
 
diff --git a/setup/resources/Microsoft.FSharp.NetSdk.Shim.props b/setup/shims/Microsoft.FSharp.NetSdk.Shim.props
similarity index 100%
rename from setup/resources/Microsoft.FSharp.NetSdk.Shim.props
rename to setup/shims/Microsoft.FSharp.NetSdk.Shim.props
diff --git a/setup/resources/Microsoft.FSharp.NetSdk.Shim.targets b/setup/shims/Microsoft.FSharp.NetSdk.Shim.targets
similarity index 100%
rename from setup/resources/Microsoft.FSharp.NetSdk.Shim.targets
rename to setup/shims/Microsoft.FSharp.NetSdk.Shim.targets
diff --git a/setup/resources/Microsoft.FSharp.Overrides.NetSdk.Shim.targets b/setup/shims/Microsoft.FSharp.Overrides.NetSdk.Shim.targets
similarity index 100%
rename from setup/resources/Microsoft.FSharp.Overrides.NetSdk.Shim.targets
rename to setup/shims/Microsoft.FSharp.Overrides.NetSdk.Shim.targets
diff --git a/setup/resources/Microsoft.FSharp.Shim.targets b/setup/shims/Microsoft.FSharp.Shim.targets
similarity index 100%
rename from setup/resources/Microsoft.FSharp.Shim.targets
rename to setup/shims/Microsoft.FSharp.Shim.targets
diff --git a/setup/resources/Microsoft.Portable.FSharp.Shim.targets b/setup/shims/Microsoft.Portable.FSharp.Shim.targets
similarity index 100%
rename from setup/resources/Microsoft.Portable.FSharp.Shim.targets
rename to setup/shims/Microsoft.Portable.FSharp.Shim.targets
diff --git a/src/absil/illib.fs b/src/absil/illib.fs
index 69b0030f910..44261606387 100644
--- a/src/absil/illib.fs
+++ b/src/absil/illib.fs
@@ -41,6 +41,10 @@ let inline isNonNull x = not (isNull x)
 let inline nonNull msg x = if isNull x then failwith ("null: " + msg) else x
 let inline (===) x y = LanguagePrimitives.PhysicalEquality x y
 
+/// Per the docs the threshold for the Large Object Heap is 85000 bytes: https://docs.microsoft.com/en-us/dotnet/standard/garbage-collection/large-object-heap#how-an-object-ends-up-on-the-large-object-heap-and-how-gc-handles-them
+/// We set the limit to slightly under that to allow for some 'slop'
+let LOH_SIZE_THRESHOLD_BYTES = 84_900
+
 //---------------------------------------------------------------------
 // Library: ReportTime
 //---------------------------------------------------------------------
@@ -91,7 +95,7 @@ module Order =
     let toFunction (pxOrder: IComparer<'U>) x y = pxOrder.Compare(x,y)
 
 //-------------------------------------------------------------------------
-// Library: arrays,lists,options
+// Library: arrays,lists,options,resizearrays
 //-------------------------------------------------------------------------
 
 module Array = 
@@ -432,6 +436,49 @@ module List =
     let existsSquared f xss = xss |> List.exists (fun xs -> xs |> List.exists (fun x -> f x))
     let mapiFoldSquared f z xss =  mapFoldSquared f z (xss |> mapiSquared (fun i j x -> (i,j,x)))
 
+module ResizeArray =
+
+    /// Split a ResizeArray into an array of smaller chunks.
+    /// This requires `items/chunkSize` Array copies of length `chunkSize` if `items/chunkSize % 0 = 0`,
+    /// otherwise `items/chunkSize + 1` Array copies.
+    let chunkBySize chunkSize f (items: ResizeArray<'t>) =
+        // we could use Seq.chunkBySize here, but that would involve many enumerator.MoveNext() calls that we can sidestep with a bit of math
+        let itemCount = items.Count
+        if itemCount = 0
+        then [||]
+        else
+            let chunksCount =
+                match itemCount / chunkSize with
+                | n when itemCount % chunkSize = 0 -> n
+                | n -> n + 1 // any remainder means we need an additional chunk to store it
+
+            [| for index in 0..chunksCount-1 do
+                let startIndex = index * chunkSize
+                let takeCount = min (itemCount - startIndex) chunkSize
+
+                let holder = Array.zeroCreate takeCount
+                // we take a bounds-check hit here on each access.
+                // other alternatives here include
+                // * iterating across an IEnumerator (incurs MoveNext penalty)
+                // * doing a block copy using `List.CopyTo(index, array, index, count)` (requires more copies to do the mapping)
+                // none are significantly better.
+                for i in 0 .. takeCount - 1 do
+                    holder.[i] <- f items.[i]
+                yield holder |]
+
+    /// Split a large ResizeArray into a series of array chunks that are each under the Large Object Heap limit.
+    /// This is done to help prevent a stop-the-world collection of the single large array, instead allowing for a greater
+    /// probability of smaller collections. Stop-the-world is still possible, just less likely.
+    let mapToSmallArrayChunks f (inp: ResizeArray<'t>) =
+        let itemSizeBytes = sizeof<'t>
+        // rounding down here is good because it ensures we don't go over
+        let maxArrayItemCount = LOH_SIZE_THRESHOLD_BYTES / itemSizeBytes
+
+        /// chunk the provided input into arrays that are smaller than the LOH limit
+        /// in order to prevent long-term storage of those values
+        chunkBySize maxArrayItemCount f inp
+
+
 /// Because FSharp.Compiler.Service is a library that will target FSharp.Core 4.5.2 for the forseeable future,
 /// we need to stick these functions in this module rather than using the module functions for ValueOption
 /// that come after FSharp.Core 4.5.2.
diff --git a/src/buildtools/Directory.Build.props b/src/buildtools/Directory.Build.props
index bb5b23d29d0..12d9ad073ec 100644
--- a/src/buildtools/Directory.Build.props
+++ b/src/buildtools/Directory.Build.props
@@ -1,3 +1,3 @@
 <Project>
-  <!-- empty to prevent directory crawling -->
+  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
 </Project>
diff --git a/src/buildtools/Directory.Build.targets b/src/buildtools/Directory.Build.targets
index bb5b23d29d0..14437118703 100644
--- a/src/buildtools/Directory.Build.targets
+++ b/src/buildtools/Directory.Build.targets
@@ -1,3 +1,3 @@
 <Project>
-  <!-- empty to prevent directory crawling -->
+  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.targets', '$(MSBuildThisFileDirectory)../'))" />
 </Project>
diff --git a/src/buildtools/buildtools.targets b/src/buildtools/buildtools.targets
index 9285a376e88..9b00e18cf72 100644
--- a/src/buildtools/buildtools.targets
+++ b/src/buildtools/buildtools.targets
@@ -15,7 +15,7 @@
           BeforeTargets="CoreCompile">
 
     <PropertyGroup>
-        <FsLexPath>$(MSBuildThisFileDirectory)fslex\bin\Proto\netcoreapp2.0\fslex.dll</FsLexPath>
+        <FsLexPath>$(ArtifactsBinDir)\fslex\Proto\netcoreapp2.0\fslex.dll</FsLexPath>
     </PropertyGroup>
 
     <!-- Create the output directory -->
@@ -38,7 +38,7 @@
           BeforeTargets="CoreCompile">
 
     <PropertyGroup>
-        <FsYaccPath>$(MSBuildThisFileDirectory)fsyacc\bin\Proto\netcoreapp2.0\fsyacc.dll</FsYaccPath>
+        <FsYaccPath>$(ArtifactsBinDir)\fsyacc\Proto\netcoreapp2.0\fsyacc.dll</FsYaccPath>
     </PropertyGroup>
 
     <!-- Create the output directory -->
diff --git a/src/fsharp/CompileOps.fs b/src/fsharp/CompileOps.fs
index 08e74a252e2..0e06f194055 100644
--- a/src/fsharp/CompileOps.fs
+++ b/src/fsharp/CompileOps.fs
@@ -2356,6 +2356,8 @@ type TcConfigBuilder =
       mutable tryGetMetadataSnapshot : ILReaderTryGetMetadataSnapshot
 
       mutable internalTestSpanStackReferring : bool
+
+      mutable noConditionalErasure : bool
       }
 
     static member Initial =
@@ -2493,6 +2495,7 @@ type TcConfigBuilder =
           shadowCopyReferences = false
           tryGetMetadataSnapshot = (fun _ -> None)
           internalTestSpanStackReferring = false
+          noConditionalErasure = false
         }
 
     static member CreateNew(legacyReferenceResolver, defaultFSharpBinariesDir, reduceMemoryUsage, implicitIncludeDir,
@@ -2954,6 +2957,8 @@ type TcConfig private (data : TcConfigBuilder, validate:bool) =
     member x.shadowCopyReferences = data.shadowCopyReferences
     member x.tryGetMetadataSnapshot = data.tryGetMetadataSnapshot
     member x.internalTestSpanStackReferring = data.internalTestSpanStackReferring
+    member x.noConditionalErasure = data.noConditionalErasure
+
     static member Create(builder, validate) = 
         use unwindBuildPhase = PushThreadBuildPhaseUntilUnwind BuildPhase.Parameter
         TcConfig(builder, validate)
@@ -3390,14 +3395,14 @@ let ComputeQualifiedNameOfFileFromUniquePath (m, p: string list) = QualifiedName
 
 let QualFileNameOfSpecs filename specs = 
     match specs with 
-    | [SynModuleOrNamespaceSig(modname, _, true, _, _, _, _, m)] -> QualFileNameOfModuleName m filename modname
-    | [SynModuleOrNamespaceSig(_, _, false, _, _, _, _, m)] -> QualFileNameOfFilename m filename
+    | [SynModuleOrNamespaceSig(modname, _, kind, _, _, _, _, m)] when kind.IsModule -> QualFileNameOfModuleName m filename modname
+    | [SynModuleOrNamespaceSig(_, _, kind, _, _, _, _, m)] when not kind.IsModule -> QualFileNameOfFilename m filename
     | _ -> QualFileNameOfFilename (mkRange filename pos0 pos0) filename
 
 let QualFileNameOfImpls filename specs = 
     match specs with 
-    | [SynModuleOrNamespace(modname, _, true, _, _, _, _, m)] -> QualFileNameOfModuleName m filename modname
-    | [SynModuleOrNamespace(_, _, false, _, _, _, _, m)] -> QualFileNameOfFilename m filename
+    | [SynModuleOrNamespace(modname, _, kind, _, _, _, _, m)] when kind.IsModule -> QualFileNameOfModuleName m filename modname
+    | [SynModuleOrNamespace(_, _, kind, _, _, _, _, m)]  when not kind.IsModule -> QualFileNameOfFilename m filename
     | _ -> QualFileNameOfFilename (mkRange filename pos0 pos0) filename
 
 let PrepandPathToQualFileName x (QualifiedNameOfFile(q)) = ComputeQualifiedNameOfFileFromUniquePath (q.idRange, pathOfLid x@[q.idText])
@@ -3426,13 +3431,14 @@ let ComputeAnonModuleName check defaultNamespace filename (m: range) =
 
 let PostParseModuleImpl (_i, defaultNamespace, isLastCompiland, filename, impl) = 
     match impl with 
-    | ParsedImplFileFragment.NamedModule(SynModuleOrNamespace(lid, isRec, isModule, decls, xmlDoc, attribs, access, m)) -> 
+    | ParsedImplFileFragment.NamedModule(SynModuleOrNamespace(lid, isRec, kind, decls, xmlDoc, attribs, access, m)) -> 
         let lid = 
             match lid with 
-            | [id] when isModule && id.idText = MangledGlobalName -> error(Error(FSComp.SR.buildInvalidModuleOrNamespaceName(), id.idRange))
+            | [id] when kind.IsModule && id.idText = MangledGlobalName ->
+                error(Error(FSComp.SR.buildInvalidModuleOrNamespaceName(), id.idRange))
             | id :: rest when id.idText = MangledGlobalName -> rest
             | _ -> lid
-        SynModuleOrNamespace(lid, isRec, isModule, decls, xmlDoc, attribs, access, m)
+        SynModuleOrNamespace(lid, isRec, kind, decls, xmlDoc, attribs, access, m)
 
     | ParsedImplFileFragment.AnonModule (defs, m)-> 
         let isLast, isExe = isLastCompiland 
@@ -3443,24 +3449,26 @@ let PostParseModuleImpl (_i, defaultNamespace, isLastCompiland, filename, impl)
             | _ -> errorR(Error(FSComp.SR.buildMultiFileRequiresNamespaceOrModule(), trimRangeToLine m))
 
         let modname = ComputeAnonModuleName (not (isNil defs)) defaultNamespace filename (trimRangeToLine m)
-        SynModuleOrNamespace(modname, false, true, defs, PreXmlDoc.Empty, [], None, m)
+        SynModuleOrNamespace(modname, false, AnonModule, defs, PreXmlDoc.Empty, [], None, m)
 
-    | ParsedImplFileFragment.NamespaceFragment (lid, a, b, c, d, e, m)-> 
-        let lid = 
+    | ParsedImplFileFragment.NamespaceFragment (lid, a, kind, c, d, e, m)-> 
+        let lid, kind = 
             match lid with 
-            | id :: rest when id.idText = MangledGlobalName -> rest
-            | _ -> lid
-        SynModuleOrNamespace(lid, a, b, c, d, e, None, m)
+            | id :: rest when id.idText = MangledGlobalName ->
+                rest, if List.isEmpty rest then GlobalNamespace else kind
+            | _ -> lid, kind
+        SynModuleOrNamespace(lid, a, kind, c, d, e, None, m)
 
 let PostParseModuleSpec (_i, defaultNamespace, isLastCompiland, filename, intf) = 
     match intf with 
-    | ParsedSigFileFragment.NamedModule(SynModuleOrNamespaceSig(lid, isRec, isModule, decls, xmlDoc, attribs, access, m)) -> 
+    | ParsedSigFileFragment.NamedModule(SynModuleOrNamespaceSig(lid, isRec, kind, decls, xmlDoc, attribs, access, m)) -> 
         let lid = 
             match lid with 
-            | [id] when isModule && id.idText = MangledGlobalName -> error(Error(FSComp.SR.buildInvalidModuleOrNamespaceName(), id.idRange))
+            | [id] when kind.IsModule && id.idText = MangledGlobalName ->
+                error(Error(FSComp.SR.buildInvalidModuleOrNamespaceName(), id.idRange))
             | id :: rest when id.idText = MangledGlobalName -> rest
             | _ -> lid
-        SynModuleOrNamespaceSig(lid, isRec, isModule, decls, xmlDoc, attribs, access, m)
+        SynModuleOrNamespaceSig(lid, isRec, NamedModule, decls, xmlDoc, attribs, access, m)
 
     | ParsedSigFileFragment.AnonModule (defs, m) -> 
         let isLast, isExe = isLastCompiland
@@ -3471,14 +3479,15 @@ let PostParseModuleSpec (_i, defaultNamespace, isLastCompiland, filename, intf)
             | _ -> errorR(Error(FSComp.SR.buildMultiFileRequiresNamespaceOrModule(), m))
 
         let modname = ComputeAnonModuleName (not (isNil defs)) defaultNamespace filename (trimRangeToLine m)
-        SynModuleOrNamespaceSig(modname, false, true, defs, PreXmlDoc.Empty, [], None, m)
+        SynModuleOrNamespaceSig(modname, false, AnonModule, defs, PreXmlDoc.Empty, [], None, m)
 
-    | ParsedSigFileFragment.NamespaceFragment (lid, a, b, c, d, e, m)-> 
-        let lid = 
+    | ParsedSigFileFragment.NamespaceFragment (lid, a, kind, c, d, e, m)-> 
+        let lid, kind = 
             match lid with 
-            | id :: rest when id.idText = MangledGlobalName -> rest
-            | _ -> lid
-        SynModuleOrNamespaceSig(lid, a, b, c, d, e, None, m)
+            | id :: rest when id.idText = MangledGlobalName ->
+                rest, if List.isEmpty rest then GlobalNamespace else kind
+            | _ -> lid, kind
+        SynModuleOrNamespaceSig(lid, a, kind, c, d, e, None, m)
 
 
 
@@ -3522,34 +3531,37 @@ let PostParseModuleSpecs (defaultNamespace, filename, isLastCompiland, ParsedSig
 
     ParsedInput.SigFile(ParsedSigFileInput(filename, qualName, scopedPragmas, hashDirectives, specs))
 
+type ModuleNamesDict = Map<string,Map<string,QualifiedNameOfFile>>
+
 /// Checks if a module name is already given and deduplicates the name if needed.
-let DeduplicateModuleName (moduleNamesDict:IDictionary<string, Set<string>>) (paths: Set<string>) path (qualifiedNameOfFile: QualifiedNameOfFile) =
-    let count = if paths.Contains path then paths.Count else paths.Count + 1
-    moduleNamesDict.[qualifiedNameOfFile.Text] <- Set.add path paths
-    let id = qualifiedNameOfFile.Id
-    if count = 1 then qualifiedNameOfFile else QualifiedNameOfFile(Ident(id.idText + "___" + count.ToString(), id.idRange))
+let DeduplicateModuleName (moduleNamesDict:ModuleNamesDict) fileName (qualNameOfFile: QualifiedNameOfFile) =
+    let path = Path.GetDirectoryName fileName
+    let path = if FileSystem.IsPathRootedShim path then try FileSystem.GetFullPathShim path with _ -> path else path
+    match moduleNamesDict.TryGetValue qualNameOfFile.Text with
+    | true, paths ->
+        if paths.ContainsKey path then 
+            paths.[path], moduleNamesDict
+        else
+            let count = paths.Count + 1
+            let id = qualNameOfFile.Id
+            let qualNameOfFileT = if count = 1 then qualNameOfFile else QualifiedNameOfFile(Ident(id.idText + "___" + count.ToString(), id.idRange))
+            let moduleNamesDictT = moduleNamesDict.Add(qualNameOfFile.Text, paths.Add(path, qualNameOfFileT))
+            qualNameOfFileT, moduleNamesDictT
+    | _ ->
+        let moduleNamesDictT = moduleNamesDict.Add(qualNameOfFile.Text, Map.empty.Add(path, qualNameOfFile))
+        qualNameOfFile, moduleNamesDictT
 
 /// Checks if a ParsedInput is using a module name that was already given and deduplicates the name if needed.
-let DeduplicateParsedInputModuleName (moduleNamesDict:IDictionary<string, Set<string>>) input =
+let DeduplicateParsedInputModuleName (moduleNamesDict: ModuleNamesDict) input =
     match input with
-    | ParsedInput.ImplFile (ParsedImplFileInput.ParsedImplFileInput(fileName, isScript, qualifiedNameOfFile, scopedPragmas, hashDirectives, modules, (isLastCompiland, isExe))) ->
-        let path = Path.GetDirectoryName fileName
-        match moduleNamesDict.TryGetValue qualifiedNameOfFile.Text with
-        | true, paths ->
-            let qualifiedNameOfFile = DeduplicateModuleName moduleNamesDict paths path qualifiedNameOfFile
-            ParsedInput.ImplFile(ParsedImplFileInput.ParsedImplFileInput(fileName, isScript, qualifiedNameOfFile, scopedPragmas, hashDirectives, modules, (isLastCompiland, isExe)))
-        | _ ->
-            moduleNamesDict.[qualifiedNameOfFile.Text] <- Set.singleton path
-            input
-    | ParsedInput.SigFile (ParsedSigFileInput.ParsedSigFileInput(fileName, qualifiedNameOfFile, scopedPragmas, hashDirectives, modules)) ->
-        let path = Path.GetDirectoryName fileName
-        match moduleNamesDict.TryGetValue qualifiedNameOfFile.Text with
-        | true, paths ->
-            let qualifiedNameOfFile = DeduplicateModuleName moduleNamesDict paths path qualifiedNameOfFile
-            ParsedInput.SigFile (ParsedSigFileInput.ParsedSigFileInput(fileName, qualifiedNameOfFile, scopedPragmas, hashDirectives, modules))
-        | _ ->
-            moduleNamesDict.[qualifiedNameOfFile.Text] <- Set.singleton path
-            input
+    | ParsedInput.ImplFile (ParsedImplFileInput.ParsedImplFileInput(fileName, isScript, qualNameOfFile, scopedPragmas, hashDirectives, modules, (isLastCompiland, isExe))) ->
+        let qualNameOfFileT, moduleNamesDictT = DeduplicateModuleName moduleNamesDict fileName qualNameOfFile
+        let inputT = ParsedInput.ImplFile(ParsedImplFileInput.ParsedImplFileInput(fileName, isScript, qualNameOfFileT, scopedPragmas, hashDirectives, modules, (isLastCompiland, isExe)))
+        inputT, moduleNamesDictT
+    | ParsedInput.SigFile (ParsedSigFileInput.ParsedSigFileInput(fileName, qualNameOfFile, scopedPragmas, hashDirectives, modules)) ->
+        let qualNameOfFileT, moduleNamesDictT = DeduplicateModuleName moduleNamesDict fileName qualNameOfFile
+        let inputT = ParsedInput.SigFile (ParsedSigFileInput.ParsedSigFileInput(fileName, qualNameOfFileT, scopedPragmas, hashDirectives, modules))
+        inputT, moduleNamesDictT
 
 let ParseInput (lexer, errorLogger:ErrorLogger, lexbuf:UnicodeLexing.Lexbuf, defaultNamespace, filename, isLastCompiland) = 
     // The assert below is almost ok, but it fires in two cases:
@@ -5446,9 +5458,12 @@ let TypeCheckOneInputEventually (checkForErrors, tcConfig:TcConfig, tcImports:Tc
               if Zset.contains qualNameOfFile tcState.tcsRootImpls then 
                   errorR(Error(FSComp.SR.buildImplementationAlreadyGivenDetail(qualNameOfFile.Text), m))
 
+              let conditionalDefines =
+                  if tcConfig.noConditionalErasure then None else Some (tcConfig.conditionalCompilationDefines)
+
               // Typecheck the signature file 
               let! (tcEnv, sigFileType, createsGeneratedProvidedTypes) = 
-                  TypeCheckOneSigFile (tcGlobals, tcState.tcsNiceNameGen, amap, tcState.tcsCcu, checkForErrors, tcConfig.conditionalCompilationDefines, tcSink, tcConfig.internalTestSpanStackReferring) tcState.tcsTcSigEnv file
+                  TypeCheckOneSigFile (tcGlobals, tcState.tcsNiceNameGen, amap, tcState.tcsCcu, checkForErrors, conditionalDefines, tcSink, tcConfig.internalTestSpanStackReferring) tcState.tcsTcSigEnv file
 
               let rootSigs = Zmap.add qualNameOfFile  sigFileType tcState.tcsRootSigs
 
@@ -5483,9 +5498,12 @@ let TypeCheckOneInputEventually (checkForErrors, tcConfig:TcConfig, tcImports:Tc
 
               let tcImplEnv = tcState.tcsTcImplEnv
 
+              let conditionalDefines =
+                  if tcConfig.noConditionalErasure then None else Some (tcConfig.conditionalCompilationDefines)
+
               // Typecheck the implementation file 
               let! topAttrs, implFile, _implFileHiddenType, tcEnvAtEnd, createsGeneratedProvidedTypes = 
-                  TypeCheckOneImplFile  (tcGlobals, tcState.tcsNiceNameGen, amap, tcState.tcsCcu, checkForErrors, tcConfig.conditionalCompilationDefines, tcSink, tcConfig.internalTestSpanStackReferring) tcImplEnv rootSigOpt file
+                  TypeCheckOneImplFile  (tcGlobals, tcState.tcsNiceNameGen, amap, tcState.tcsCcu, checkForErrors, conditionalDefines, tcSink, tcConfig.internalTestSpanStackReferring) tcImplEnv rootSigOpt file
 
               let hadSig = rootSigOpt.IsSome
               let implFileSigType = SigTypeOfImplFile implFile
diff --git a/src/fsharp/CompileOps.fsi b/src/fsharp/CompileOps.fsi
index 0e9f53c843e..fbacb77738e 100755
--- a/src/fsharp/CompileOps.fsi
+++ b/src/fsharp/CompileOps.fsi
@@ -60,12 +60,13 @@ val ComputeQualifiedNameOfFileFromUniquePath: range * string list -> Ast.Qualifi
 
 val PrependPathToInput: Ast.Ident list -> Ast.ParsedInput -> Ast.ParsedInput
 
-/// Checks if a module name is already given and deduplicates the name if needed.
-val DeduplicateModuleName: IDictionary<string,Set<string>> -> Set<string> -> string -> Ast.QualifiedNameOfFile -> Ast.QualifiedNameOfFile
+/// State used to de-deuplicate module names along a list of file names
+type ModuleNamesDict = Map<string,Map<string,QualifiedNameOfFile>>
 
 /// Checks if a ParsedInput is using a module name that was already given and deduplicates the name if needed.
-val DeduplicateParsedInputModuleName: IDictionary<string,Set<string>> -> Ast.ParsedInput -> Ast.ParsedInput
+val DeduplicateParsedInputModuleName: ModuleNamesDict -> Ast.ParsedInput -> Ast.ParsedInput * ModuleNamesDict
 
+/// Parse a single input (A signature file or implementation file)
 val ParseInput: (UnicodeLexing.Lexbuf -> Parser.token) * ErrorLogger * UnicodeLexing.Lexbuf * string option * string * isLastCompiland:(bool * bool) -> Ast.ParsedInput
 
 //----------------------------------------------------------------------------
@@ -367,6 +368,9 @@ type TcConfigBuilder =
 
       /// if true - 'let mutable x = Span.Empty', the value 'x' is a stack referring span. Used for internal testing purposes only until we get true stack spans.
       mutable internalTestSpanStackReferring : bool
+
+      /// Prevent erasure of conditional attributes and methods so tooling is able analyse them.
+      mutable noConditionalErasure: bool
     }
 
     static member Initial: TcConfigBuilder
diff --git a/src/fsharp/CompileOptions.fs b/src/fsharp/CompileOptions.fs
index 6ae18644dea..344c0e1412a 100644
--- a/src/fsharp/CompileOptions.fs
+++ b/src/fsharp/CompileOptions.fs
@@ -848,8 +848,8 @@ let testFlag tcConfigB =
                                             | str                -> warning(Error(FSComp.SR.optsUnknownArgumentToTheTestSwitch(str),rangeCmdArgs))), None,
                            None)
 
-// not shown in fsc.exe help, no warning on use, motivation is for use from VS
-let vsSpecificFlags (tcConfigB: TcConfigBuilder) = 
+// Not shown in fsc.exe help, no warning on use, motivation is for use from tooling.
+let editorSpecificFlags (tcConfigB: TcConfigBuilder) = 
   [ CompilerOption("vserrors", tagNone, OptionUnit (fun () -> tcConfigB.errorStyle <- ErrorStyle.VSErrors), None, None)
     CompilerOption("validate-type-providers", tagNone, OptionUnit (id), None, None)  // preserved for compatibility's sake, no longer has any effect
     CompilerOption("LCID", tagInt, OptionInt ignore, None, None)
@@ -857,7 +857,8 @@ let vsSpecificFlags (tcConfigB: TcConfigBuilder) =
     CompilerOption("sqmsessionguid", tagNone, OptionString ignore, None, None)
     CompilerOption("gccerrors", tagNone, OptionUnit (fun () -> tcConfigB.errorStyle <- ErrorStyle.GccErrors), None, None) 
     CompilerOption("exename", tagNone, OptionString (fun s -> tcConfigB.exename <- Some(s)), None, None)
-    CompilerOption("maxerrors", tagInt, OptionInt (fun n -> tcConfigB.maxErrors <- n), None, None) ]
+    CompilerOption("maxerrors", tagInt, OptionInt (fun n -> tcConfigB.maxErrors <- n), None, None)
+    CompilerOption("noconditionalerasure", tagNone, OptionUnit (fun () -> tcConfigB.noConditionalErasure <- true), None, None) ]
 
 let internalFlags (tcConfigB:TcConfigBuilder) =
   [
@@ -896,7 +897,7 @@ let internalFlags (tcConfigB:TcConfigBuilder) =
     CompilerOption("alwayscallvirt",tagNone,OptionSwitch(callVirtSwitch tcConfigB),Some(InternalCommandLineOption("alwayscallvirt",rangeCmdArgs)), None)
     CompilerOption("nodebugdata",tagNone, OptionUnit (fun () -> tcConfigB.noDebugData<-true),Some(InternalCommandLineOption("--nodebugdata",rangeCmdArgs)), None)
     testFlag tcConfigB  ] @
-  vsSpecificFlags tcConfigB @
+  editorSpecificFlags tcConfigB @
   [ CompilerOption("jit", tagNone, OptionSwitch (jitoptimizeSwitch tcConfigB), Some(InternalCommandLineOption("jit", rangeCmdArgs)), None)
     CompilerOption("localoptimize", tagNone, OptionSwitch(localoptimizeSwitch tcConfigB),Some(InternalCommandLineOption("localoptimize", rangeCmdArgs)), None)
     CompilerOption("splitting", tagNone, OptionSwitch(splittingSwitch tcConfigB),Some(InternalCommandLineOption("splitting", rangeCmdArgs)), None)
diff --git a/src/fsharp/Directory.Build.props b/src/fsharp/Directory.Build.props
index 57c8aa24ba7..151415117e4 100644
--- a/src/fsharp/Directory.Build.props
+++ b/src/fsharp/Directory.Build.props
@@ -6,6 +6,7 @@
     <DisableImplicitSystemValueTupleReference>true</DisableImplicitSystemValueTupleReference>
     <DisableImplicitFSharpCoreReference>true</DisableImplicitFSharpCoreReference>
     <UseStandardResourceNames>false</UseStandardResourceNames>
+    <PackageOutputPath>$(ArtifactsPackagesDir)\$(Configuration)</PackageOutputPath>
   </PropertyGroup>
 
 </Project>
diff --git a/src/fsharp/Directory.Nuget.props b/src/fsharp/Directory.Nuget.props
index 97266b7c79d..6521936cfe3 100644
--- a/src/fsharp/Directory.Nuget.props
+++ b/src/fsharp/Directory.Nuget.props
@@ -20,6 +20,7 @@
       tags=$(PackageTags);
       githeadsha=$(NormalizedGitHeadSha);
       configuration=$(Configuration);
+      artifactsbindir=$(ArtifactsBinDir);
     </NuspecProperties>
   </PropertyGroup>
 
diff --git a/src/fsharp/Directory.Nuget.targets b/src/fsharp/Directory.Nuget.targets
index f3ae171dc38..e30b155faad 100644
--- a/src/fsharp/Directory.Nuget.targets
+++ b/src/fsharp/Directory.Nuget.targets
@@ -8,14 +8,4 @@
     </NuspecProperties>
   </PropertyGroup>
 
-  <Target Name="CopyPackageToArtifactsDirectory"
-          AfterTargets="Pack">
-    <ItemGroup>
-      <NugetPackages Include="$(MSBuildProjectDirectory)\**\$(PackageId).*.nupkg" />
-    </ItemGroup>
-    <MakeDir Directories="$(RepoRoot)artifacts;$(RepoRoot)$(Configuration)\artifacts" />
-    <Copy SourceFiles="@(NugetPackages)" DestinationFolder="$(RepoRoot)\artifacts" />
-    <Copy SourceFiles="@(NugetPackages)" DestinationFolder="$(RepoRoot)\$(Configuration)\artifacts" />
-  </Target>
-
 </Project>
diff --git a/src/fsharp/ErrorResolutionHints.fs b/src/fsharp/ErrorResolutionHints.fs
index e674adb6f46..20bcb13fd21 100644
--- a/src/fsharp/ErrorResolutionHints.fs
+++ b/src/fsharp/ErrorResolutionHints.fs
@@ -43,6 +43,7 @@ let FilterPredictions (idText:string) (suggestionF:ErrorLogger.Suggestions) =
             name |> Seq.forall (fun c -> c <> ' ')
 
     if allSuggestions.Contains idText then [] else // some other parsing error occurred
+    let dotIdText = "." + idText
     allSuggestions
     |> Seq.choose (fun suggestion ->
         // Because beginning a name with _ is used both to indicate an unused
@@ -53,7 +54,7 @@ let FilterPredictions (idText:string) (suggestionF:ErrorLogger.Suggestions) =
         let suggestion:string = demangle suggestion
         let suggestedText = suggestion.ToUpperInvariant()
         let similarity = EditDistance.JaroWinklerDistance uppercaseText suggestedText
-        if similarity >= highConfidenceThreshold || suggestion.EndsWithOrdinal("." + idText) then
+        if similarity >= highConfidenceThreshold || suggestion.EndsWithOrdinal(dotIdText) then
             Some(similarity, suggestion)
         elif similarity < minThresholdForSuggestions && suggestedText.Length > minStringLengthForThreshold then
             None
diff --git a/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj b/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
index cb84565e52d..b7be3a4f364 100644
--- a/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
+++ b/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
@@ -13,6 +13,7 @@
     <OtherFlags>$(OtherFlags) --warnon:1182 --maxerrors:20 --extraoptimizationloops:1</OtherFlags>
     <UseFSharpProductVersion>true</UseFSharpProductVersion>
     <UseAssetTargetFallback>true</UseAssetTargetFallback>
+    <Tailcalls>true</Tailcalls> <!-- .tail annotations always emitted for this binary, even in debug mode -->
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(TargetFramework)' == 'net472' AND '$(OS)' == 'Windows_NT'">
@@ -29,14 +30,16 @@
   </PropertyGroup>
 
   <Target Name="CopyToBuiltBin" BeforeTargets="BuiltProjectOutputGroup" AfterTargets="CoreCompile">
+    <PropertyGroup>
+      <BuildOutputGroupLocation>$(BaseOutputPath)\$(Configuration)\$(TargetFramework)</BuildOutputGroupLocation>
+    </PropertyGroup>
     <ItemGroup>
-      <BuiltProjectOutputGroupKeyOutput Include="$(FSharpSourcesRoot)\..\$(Configuration)\net40\bin\Microsoft.Build.Framework.dll" />
-      <BuiltProjectOutputGroupKeyOutput Include="$(FSharpSourcesRoot)\..\$(Configuration)\net40\bin\Microsoft.Build.dll" />
-      <BuiltProjectOutputGroupKeyOutput Include="$(FSharpSourcesRoot)\..\$(Configuration)\net40\bin\Microsoft.Build.Utilities.Core.dll" />
-      <BuiltProjectOutputGroupKeyOutput Include="$(FSharpSourcesRoot)\..\$(Configuration)\net40\bin\Microsoft.Build.Tasks.Core.dll" />
-      <BuiltProjectOutputGroupKeyOutput Include="$(FSharpSourcesRoot)\..\$(Configuration)\net40\bin\System.Reflection.Metadata.dll" />
-      <BuiltProjectOutputGroupKeyOutput Include="$(FSharpSourcesRoot)\..\$(Configuration)\net40\bin\System.Collections.Immutable.dll" />
-      <BuiltProjectOutputGroupKeyOutput Include="$(FSharpSourcesRoot)\..\$(Configuration)\net40\bin\System.ValueTuple.dll" Condition="'$(MonoPackaging)' == 'true'" />
+      <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\Microsoft.Build.Framework.dll" />
+      <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\Microsoft.Build.dll" />
+      <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\Microsoft.Build.Utilities.Core.dll" />
+      <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\Microsoft.Build.Tasks.Core.dll" />
+      <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\System.Reflection.Metadata.dll" />
+      <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\System.Collections.Immutable.dll" />
     </ItemGroup>
   </Target>
 
diff --git a/src/fsharp/FSharp.Compiler.nuget/Directory.Build.props b/src/fsharp/FSharp.Compiler.nuget/Directory.Build.props
index 68113d9e9ca..8093275dba0 100644
--- a/src/fsharp/FSharp.Compiler.nuget/Directory.Build.props
+++ b/src/fsharp/FSharp.Compiler.nuget/Directory.Build.props
@@ -6,8 +6,6 @@
   <PropertyGroup>
     <TargetFramework>netcoreapp2.1</TargetFramework>
     <NuspecFile>Microsoft.FSharp.Compiler.nuspec</NuspecFile>
-    <PreReleaseSuffix Condition="'$(PreRelease)' != 'false'">-rtm-$(NuGetPackageVersionSuffix)</PreReleaseSuffix>
-    <PackageVersion>$(FSPackageVersion)$(PreReleaseSuffix)</PackageVersion>
   </PropertyGroup>
 
 </Project>
diff --git a/src/fsharp/FSharp.Compiler.nuget/Directory.Build.targets b/src/fsharp/FSharp.Compiler.nuget/Directory.Build.targets
index a20d4be41e6..2721c93a906 100644
--- a/src/fsharp/FSharp.Compiler.nuget/Directory.Build.targets
+++ b/src/fsharp/FSharp.Compiler.nuget/Directory.Build.targets
@@ -1,11 +1,16 @@
 <Project>
 
+  <PropertyGroup>
+    <PreReleaseSuffix Condition="'$(PreRelease)' != 'false'">-rtm-$(NuGetPackageVersionSuffix)</PreReleaseSuffix>
+    <PackageVersion>$(FSPackageVersion)$(PreReleaseSuffix)</PackageVersion>
+  </PropertyGroup>
+
   <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.targets', '$(MSBuildThisFileDirectory)../'))" />
   <Import Project="$(MSBuildThisFileDirectory)..\Directory.Nuget.targets" />
 
   <ItemGroup>
-    <ProjectReference Include="..\Fsc\Fsc.fsproj" />
-    <ProjectReference Include="..\fsi\Fsi.fsproj" />
+    <ProjectReference Include="..\fsc\fsc.fsproj" />
+    <ProjectReference Include="..\fsi\fsi.fsproj" />
     <ProjectReference Include="..\FSharp.Build\FSharp.Build.fsproj" />
     <ProjectReference Include="..\FSharp.Compiler.Interactive.Settings\FSharp.Compiler.Interactive.Settings.fsproj" />
   </ItemGroup>
diff --git a/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.Prerelease.csproj b/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.Prerelease.csproj
new file mode 100644
index 00000000000..692e5aba1b2
--- /dev/null
+++ b/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.Prerelease.csproj
@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <PackageId>Microsoft.FSharp.Compiler</PackageId>
+    <PreRelease>true</PreRelease>
+  </PropertyGroup>
+
+</Project>
diff --git a/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.csproj b/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.csproj
index eef53d7dc4e..abb19e418fe 100644
--- a/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.csproj
+++ b/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.csproj
@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <PackageId>Microsoft.FSharp.Compiler</PackageId>
+    <PreRelease>false</PreRelease>
   </PropertyGroup>
 
 </Project>
diff --git a/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.nuspec b/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.nuspec
index ac76a4a2403..f10712a641e 100644
--- a/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.nuspec
+++ b/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.nuspec
@@ -54,30 +54,30 @@
             this approach gives a very small deployment. Which is kind of necessary.
         -->
         <!-- assemblies -->
-        <file src="bin\$configuration$\netcoreapp2.1\fsc.exe"                                     target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\fsi.exe"                                     target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\FSharp.Core.dll"                             target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\FSharp.Compiler.Private.dll"                 target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\FSharp.Build.dll"                            target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\FSharp.Compiler.Interactive.Settings.dll"    target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\fsc\$configuration$\netcoreapp2.1\fsc.exe"                                                                    target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\fsi\$configuration$\netcoreapp2.1\fsi.exe"                                                                    target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\netstandard1.6\FSharp.Core.dll"                                                   target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\FSharp.Compiler.Private\$configuration$\netstandard1.6\FSharp.Compiler.Private.dll"                           target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\FSharp.Build\$configuration$\netstandard2.0\FSharp.Build.dll"                                                 target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\FSharp.Compiler.Interactive.Settings\$configuration$\netstandard1.6\FSharp.Compiler.Interactive.Settings.dll" target="lib\netcoreapp2.1" />
         <!-- symbols -->
-        <file src="bin\$configuration$\netcoreapp2.1\fsc.pdb"                                     target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\fsi.pdb"                                     target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\FSharp.Core.pdb"                             target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\FSharp.Compiler.Private.pdb"                 target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\FSharp.Build.pdb"                            target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\FSharp.Compiler.Interactive.Settings.pdb"    target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\fsc\$configuration$\netcoreapp2.1\fsc.pdb"                                                                    target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\fsi\$configuration$\netcoreapp2.1\fsi.pdb"                                                                    target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\netstandard1.6\FSharp.Core.pdb"                                                   target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\FSharp.Compiler.Private\$configuration$\netstandard1.6\FSharp.Compiler.Private.pdb"                           target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\FSharp.Build\$configuration$\netstandard2.0\FSharp.Build.pdb"                                                 target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\FSharp.Compiler.Interactive.Settings\$configuration$\netstandard1.6\FSharp.Compiler.Interactive.Settings.pdb" target="lib\netcoreapp2.1" />
         <!-- additional files -->
-        <file src="bin\$configuration$\netcoreapp2.1\default.win32manifest"                       target="contentFiles\any\any"  />
-        <file src="bin\$configuration$\netcoreapp2.1\Microsoft.FSharp.Targets"                    target="contentFiles\any\any"  />
-        <file src="bin\$configuration$\netcoreapp2.1\Microsoft.Portable.FSharp.Targets"           target="contentFiles\any\any"  />
-        <file src="bin\$configuration$\netcoreapp2.1\Microsoft.FSharp.NetSdk.props"               target="contentFiles\any\any"  />
-        <file src="bin\$configuration$\netcoreapp2.1\Microsoft.FSharp.NetSdk.targets"             target="contentFiles\any\any"  />
-        <file src="bin\$configuration$\netcoreapp2.1\Microsoft.FSharp.Overrides.NetSdk.targets"   target="contentFiles\any\any"  />
+        <file src="$artifactsbindir$\fsc\$configuration$\netcoreapp2.1\default.win32manifest"                               target="contentFiles\any\any" />
+        <file src="$artifactsbindir$\FSharp.Build\$configuration$\netstandard2.0\Microsoft.FSharp.Targets"                  target="contentFiles\any\any" />
+        <file src="$artifactsbindir$\FSharp.Build\$configuration$\netstandard2.0\Microsoft.Portable.FSharp.Targets"         target="contentFiles\any\any" />
+        <file src="$artifactsbindir$\FSharp.Build\$configuration$\netstandard2.0\Microsoft.FSharp.NetSdk.props"             target="contentFiles\any\any" />
+        <file src="$artifactsbindir$\FSharp.Build\$configuration$\netstandard2.0\Microsoft.FSharp.NetSdk.targets"           target="contentFiles\any\any" />
+        <file src="$artifactsbindir$\FSharp.Build\$configuration$\netstandard2.0\Microsoft.FSharp.Overrides.NetSdk.targets" target="contentFiles\any\any" />
         <!-- resources -->
-        <file src="bin\$configuration$\netcoreapp2.1\**\FSharp.Core.resources.dll"                          target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\**\FSharp.Compiler.Private.resources.dll"              target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\**\FSharp.Compiler.Interactive.Settings.resources.dll" target="lib\netcoreapp2.1" />
-        <file src="bin\$configuration$\netcoreapp2.1\**\FSharp.Build.resources.dll"                         target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\netstandard1.6\**\FSharp.Core.resources.dll"                                                   target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\FSharp.Compiler.Private\$configuration$\netstandard1.6\**\FSharp.Compiler.Private.resources.dll"                           target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\FSharp.Compiler.Interactive.Settings\$configuration$\netstandard1.6\**\FSharp.Compiler.Interactive.Settings.resources.dll" target="lib\netcoreapp2.1" />
+        <file src="$artifactsbindir$\FSharp.Build\$configuration$\netstandard2.0\**\FSharp.Build.resources.dll"                                                 target="lib\netcoreapp2.1" />
     </files>
 </package>
diff --git a/src/fsharp/FSharp.Compiler.nuget/Testing.FSharp.Compiler.csproj b/src/fsharp/FSharp.Compiler.nuget/Testing.FSharp.Compiler.csproj
index 44a831fed38..aaee9c73942 100644
--- a/src/fsharp/FSharp.Compiler.nuget/Testing.FSharp.Compiler.csproj
+++ b/src/fsharp/FSharp.Compiler.nuget/Testing.FSharp.Compiler.csproj
@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <PackageId>Testing.FSharp.Compiler</PackageId>
+    <PreRelease>true</PreRelease>
   </PropertyGroup>
 
 </Project>
diff --git a/src/fsharp/FSharp.Core/FSharp.Core.fsproj b/src/fsharp/FSharp.Core/FSharp.Core.fsproj
index ce9fa915f91..6ddda3f2e7e 100644
--- a/src/fsharp/FSharp.Core/FSharp.Core.fsproj
+++ b/src/fsharp/FSharp.Core/FSharp.Core.fsproj
@@ -14,6 +14,7 @@
     <DefineConstants>$(DefineConstants);FSHARP_CORE</DefineConstants>
     <DefineConstants Condition="'$(Configuration)' == 'Proto'">BUILDING_WITH_LKG;$(DefineConstants)</DefineConstants>
     <OtherFlags>$(OtherFlags) --warnon:1182 --compiling-fslib --compiling-fslib-40 --maxerrors:20 --extraoptimizationloops:1</OtherFlags>
+    <Tailcalls>true</Tailcalls> <!-- .tail annotations always emitted for this binary, even in debug mode -->
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/fsharp/FSharp.Core/FSharp.Core.nuspec b/src/fsharp/FSharp.Core/FSharp.Core.nuspec
index 21b484cb8ab..443388a8278 100644
--- a/src/fsharp/FSharp.Core/FSharp.Core.nuspec
+++ b/src/fsharp/FSharp.Core/FSharp.Core.nuspec
@@ -56,18 +56,18 @@
         </dependencies>
     </metadata>
     <files>
-        <file src="bin\$configuration$\netstandard1.6\FSharp.Core.dll"          target="lib\netstandard1.6" />
-        <file src="bin\$configuration$\netstandard1.6\FSharp.Core.sigdata"      target="lib\netstandard1.6" />
-        <file src="bin\$configuration$\netstandard1.6\FSharp.Core.optdata"      target="lib\netstandard1.6" />
-        <file src="bin\$configuration$\netstandard1.6\FSharp.Core.xml"          target="lib\netstandard1.6" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\netstandard1.6\FSharp.Core.dll"     target="lib\netstandard1.6" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\netstandard1.6\FSharp.Core.sigdata" target="lib\netstandard1.6" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\netstandard1.6\FSharp.Core.optdata" target="lib\netstandard1.6" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\netstandard1.6\FSharp.Core.xml"     target="lib\netstandard1.6" />
 
-        <file src="bin\$configuration$\net45\FSharp.Core.dll"            target="lib\net45" />
-        <file src="bin\$configuration$\net45\FSharp.Core.sigdata"        target="lib\net45" />
-        <file src="bin\$configuration$\net45\FSharp.Core.optdata"        target="lib\net45" />
-        <file src="bin\$configuration$\net45\FSharp.Core.xml"            target="lib\net45" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\net45\FSharp.Core.dll"     target="lib\net45" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\net45\FSharp.Core.sigdata" target="lib\net45" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\net45\FSharp.Core.optdata" target="lib\net45" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\net45\FSharp.Core.xml"     target="lib\net45" />
 
         <!-- resources -->
-        <file src="bin\$configuration$\netstandard1.6\**\FSharp.Core.resources.dll" target="lib\netstandard1.6" />
-        <file src="bin\$configuration$\net45\**\FSharp.Core.resources.dll"   target="lib\net45" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\netstandard1.6\**\FSharp.Core.resources.dll" target="lib\netstandard1.6" />
+        <file src="$artifactsbindir$\FSharp.Core\$configuration$\**\FSharp.Core.resources.dll"                target="lib\net45" />
     </files>
 </package>
diff --git a/src/fsharp/FSharp.Core/map.fs b/src/fsharp/FSharp.Core/map.fs
index 8efc49a1a41..7ef250a0ee9 100644
--- a/src/fsharp/FSharp.Core/map.fs
+++ b/src/fsharp/FSharp.Core/map.fs
@@ -558,7 +558,7 @@ namespace Microsoft.FSharp.Collections
             for (KeyValue(x,y)) in this do
                 res <- combineHash res (hash x)
                 res <- combineHash res (Unchecked.hash y)
-            abs res
+            res
 
         override this.Equals(that) = 
             match that with 
@@ -744,4 +744,4 @@ namespace Microsoft.FSharp.Collections
         let empty<'Key,'Value  when 'Key : comparison> = Map<'Key,'Value>.Empty
 
         [<CompiledName("Count")>]
-        let count (table:Map<_,_>) = table.Count
\ No newline at end of file
+        let count (table:Map<_,_>) = table.Count
diff --git a/src/fsharp/IlxGen.fs b/src/fsharp/IlxGen.fs
index 9bd796db143..d027afabeb5 100644
--- a/src/fsharp/IlxGen.fs
+++ b/src/fsharp/IlxGen.fs
@@ -764,7 +764,7 @@ let StorageForVal m v eenv =
         try eenv.valsInScope.[v]
         with :? KeyNotFoundException ->
           assert false
-          errorR(Error(FSComp.SR.ilUndefinedValue(showL(vspecAtBindL v)),m)) 
+          errorR(Error(FSComp.SR.ilUndefinedValue(showL(valAtBindL v)),m)) 
           notlazy (Arg 668(* random value for post-hoc diagnostic analysis on generated tree *) )
     v.Force()
 
diff --git a/src/fsharp/NameResolution.fs b/src/fsharp/NameResolution.fs
index 09ab9e1945b..e39df6094da 100644
--- a/src/fsharp/NameResolution.fs
+++ b/src/fsharp/NameResolution.fs
@@ -1213,7 +1213,7 @@ let GetNestedTypesOfType (ad, ncenv:NameResolver, optFilter, staticResInfo, chec
 //------------------------------------------------------------------------- 
 
 /// Represents the kind of the occurrence when reporting a name in name resolution
-[<RequireQualifiedAccess>]
+[<RequireQualifiedAccess; Struct>]
 type ItemOccurence = 
     /// This is a binding / declaration of the item
     | Binding 
@@ -1501,17 +1501,24 @@ type TcSymbolUseData =
 /// This is a memory-critical data structure - allocations of this data structure and its immediate contents
 /// is one of the highest memory long-lived data structures in typical uses of IDEs. Not many of these objects
 /// are allocated (one per file), but they are large because the allUsesOfAllSymbols array is large.
-type TcSymbolUses(g, capturedNameResolutions : ResizeArray<CapturedNameResolution>, formatSpecifierLocations: (range * int)[]) = 
-    
+type TcSymbolUses(g, capturedNameResolutions : ResizeArray<CapturedNameResolution>, formatSpecifierLocations: (range * int)[]) =
+
     // Make sure we only capture the information we really need to report symbol uses
-    let allUsesOfSymbols = [| for cnr in capturedNameResolutions -> { Item=cnr.Item; ItemOccurence=cnr.ItemOccurence; DisplayEnv=cnr.DisplayEnv; Range=cnr.Range } |]
+    let allUsesOfSymbols =
+        capturedNameResolutions
+        |> ResizeArray.mapToSmallArrayChunks (fun cnr -> { Item=cnr.Item; ItemOccurence=cnr.ItemOccurence; DisplayEnv=cnr.DisplayEnv; Range=cnr.Range })
+
     let capturedNameResolutions = () 
     do ignore capturedNameResolutions // don't capture this!
 
     member this.GetUsesOfSymbol(item) = 
-        [| for symbolUse in allUsesOfSymbols do
-               if protectAssemblyExploration false (fun () -> ItemsAreEffectivelyEqual g item symbolUse.Item) then
-                  yield symbolUse |]
+        // This member returns what is potentially a very large array, which may approach the size constraints of the Large Object Heap.
+        // This is unlikely in practice, though, because we filter down the set of all symbol uses to those specifically for the given `item`.
+        // Consequently we have a much lesser chance of ending up with an array large enough to be promoted to the LOH.
+        [| for symbolUseChunk in allUsesOfSymbols do
+            for symbolUse in symbolUseChunk do
+                if protectAssemblyExploration false (fun () -> ItemsAreEffectivelyEqual g item symbolUse.Item) then
+                    yield symbolUse |]
 
     member this.AllUsesOfSymbols = allUsesOfSymbols
 
diff --git a/src/fsharp/NameResolution.fsi b/src/fsharp/NameResolution.fsi
index 8912c8946a5..bed09846767 100755
--- a/src/fsharp/NameResolution.fsi
+++ b/src/fsharp/NameResolution.fsi
@@ -241,7 +241,7 @@ type TypeNameResolutionInfo =
   static member ResolveToTypeRefs : TypeNameResolutionStaticArgsInfo -> TypeNameResolutionInfo
 
 /// Represents the kind of the occurrence when reporting a name in name resolution
-[<RequireQualifiedAccess>]
+[<RequireQualifiedAccess; Struct>]
 type internal ItemOccurence = 
     | Binding 
     | Use 
@@ -320,7 +320,7 @@ type internal TcSymbolUses =
     member GetUsesOfSymbol : Item -> TcSymbolUseData[]
 
     /// All the uses of all items within the file
-    member AllUsesOfSymbols : TcSymbolUseData[]
+    member AllUsesOfSymbols : TcSymbolUseData[][]
 
     /// Get the locations of all the printf format specifiers in the file
     member GetFormatSpecifierLocationsAndArity : unit -> (range * int)[]
diff --git a/src/fsharp/Optimizer.fs b/src/fsharp/Optimizer.fs
index 9b228d60044..96d94d16e93 100644
--- a/src/fsharp/Optimizer.fs
+++ b/src/fsharp/Optimizer.fs
@@ -976,11 +976,11 @@ let AbstractLazyModulInfoByHiding isAssemblyBoundary mhi =
     // Under those checks, the further hidden* checks may be subsumed (meaning, not required anymore).
 
     let hiddenTycon, hiddenTyconRepr, hiddenVal, hiddenRecdField, hiddenUnionCase = 
-        Zset.memberOf mhi.mhiTycons, 
-        Zset.memberOf mhi.mhiTyconReprs, 
-        Zset.memberOf mhi.mhiVals, 
-        Zset.memberOf mhi.mhiRecdFields, 
-        Zset.memberOf mhi.mhiUnionCases
+        Zset.memberOf mhi.HiddenTycons, 
+        Zset.memberOf mhi.HiddenTyconReprs, 
+        Zset.memberOf mhi.HiddenVals, 
+        Zset.memberOf mhi.HiddenRecdFields, 
+        Zset.memberOf mhi.HiddenUnionCases
 
     let rec abstractExprInfo ivalue = 
         match ivalue with 
@@ -3236,7 +3236,7 @@ and OptimizeModuleExpr cenv env x =
                     not (ValueIsUsedOrHasEffect cenv (fun () -> fvs.FreeLocals) (bind, binfo)) &&
 
                     // Check the thing is hidden by the signature (if any)
-                    hidden.mhiVals.Contains bind.Var && 
+                    hidden.HiddenVals.Contains bind.Var && 
 
                     // Check the thing is not compiled as a static field or property, since reflected definitions and other reflective stuff might need it
                     not (IsCompiledAsStaticProperty cenv.g bind.Var))
diff --git a/src/fsharp/SignatureConformance.fs b/src/fsharp/SignatureConformance.fs
index ed5c04da71f..ac0c23e9709 100644
--- a/src/fsharp/SignatureConformance.fs
+++ b/src/fsharp/SignatureConformance.fs
@@ -37,8 +37,8 @@ type Checker(g, amap, denv, remapInfo: SignatureRepackageInfo, checkingSig) =
         // Used when checking attributes.
         let sigToImplRemap = 
             let remap = Remap.Empty 
-            let remap = (remapInfo.mrpiEntities,remap) ||> List.foldBack (fun (implTcref ,signTcref) acc -> addTyconRefRemap signTcref implTcref acc) 
-            let remap = (remapInfo.mrpiVals    ,remap) ||> List.foldBack (fun (implValRef,signValRef) acc -> addValRemap signValRef.Deref implValRef.Deref acc) 
+            let remap = (remapInfo.RepackagedEntities,remap) ||> List.foldBack (fun (implTcref ,signTcref) acc -> addTyconRefRemap signTcref implTcref acc) 
+            let remap = (remapInfo.RepackagedVals    ,remap) ||> List.foldBack (fun (implValRef,signValRef) acc -> addValRemap signValRef.Deref implValRef.Deref acc) 
             remap
             
         // For all attributable elements (types, modules, exceptions, record fields, unions, parameters, generic type parameters)
diff --git a/src/fsharp/TastOps.fs b/src/fsharp/TastOps.fs
index 19414aa5f5b..23242b1aff6 100644
--- a/src/fsharp/TastOps.fs
+++ b/src/fsharp/TastOps.fs
@@ -3442,7 +3442,7 @@ module DebugPrint = begin
     let rec MemberL (v:Val) (membInfo:ValMemberInfo) = 
         (aboveListL [ wordL(tagText "compiled_name! = ") ^^ wordL (tagText v.CompiledName) ;
                       wordL(tagText "membInfo-slotsig! = ") ^^ listL slotSigL membInfo.ImplementedSlotSigs ]) 
-    and vspecAtBindL  v = 
+    and valAtBindL  v = 
         let vL = valL v  in
         let mutL = (if v.IsMutable then wordL(tagText "mutable") ++ vL else vL)
         mutL  --- (aboveListL (List.concat [[wordL(tagText ":") ^^ typeL v.Type];
@@ -3512,7 +3512,7 @@ module DebugPrint = begin
             then emptyL 
             else 
                 let iimplsLs = iimpls |> List.map (fun (ty, _, _) -> wordL(tagText "interface") --- typeL ty)
-                let adhocLs  = adhoc  |> List.map (fun vref -> vspecAtBindL  vref.Deref)
+                let adhocLs  = adhoc  |> List.map (fun vref -> valAtBindL  vref.Deref)
                 (wordL(tagText "with") @@-- aboveListL (iimplsLs @ adhocLs)) @@ wordL(tagText "end")
 
         let layoutUnionCaseArgTypes argtys = sepListL (wordL(tagText "*")) (List.map typeL argtys)
@@ -3559,7 +3559,7 @@ module DebugPrint = begin
                     let vsprs = 
                         tycon.MembersOfFSharpTyconSorted 
                             |> List.filter (fun v -> v.IsDispatchSlot) 
-                            |> List.map (fun vref -> vspecAtBindL vref.Deref)
+                            |> List.map (fun vref -> valAtBindL vref.Deref)
                     let vals  = tycon.TrueFieldsAsList |> List.map (fun f -> (if f.IsStatic then wordL(tagText "static") else emptyL) ^^ wordL(tagText "val") ^^ layoutRecdField f)
                     let alldecls = inherits @ vsprs @ vals
                     let emptyMeasure = match tycon.TypeOrMeasureKind with TyparKind.Measure -> isNil alldecls | _ -> false
@@ -3590,7 +3590,7 @@ module DebugPrint = begin
     //--------------------------------------------------------------------------
 
     and bindingL (TBind(v, repr, _)) =
-        vspecAtBindL v --- (wordL(tagText "=") ^^ exprL repr)
+        valAtBindL v --- (wordL(tagText "=") ^^ exprL repr)
 
     and exprL expr = exprWrapL false expr
     and atomL expr = exprWrapL true  expr // true means bracket if needed to be atomic expr 
@@ -3628,11 +3628,11 @@ module DebugPrint = begin
                     | ThenDoSeq   -> "; (*ThenDo*)" 
                 ((exprL x0 ^^ rightL (tagText flag)) @@ exprL x1) |> wrap
             | Expr.Lambda(_, _, baseValOpt, argvs, body, _, _)  -> 
-                let formalsL = spaceListL (List.map vspecAtBindL argvs) in
+                let formalsL = spaceListL (List.map valAtBindL argvs) in
                 let bindingL = 
                     match baseValOpt with
                     | None       -> wordL(tagText "lam") ^^ formalsL ^^ rightL(tagText ".")
-                    | Some basev -> wordL(tagText "lam") ^^ (leftL(tagText "base=") ^^ vspecAtBindL basev) --- formalsL ^^ rightL(tagText ".") in
+                    | Some basev -> wordL(tagText "lam") ^^ (leftL(tagText "base=") ^^ valAtBindL basev) --- formalsL ^^ rightL(tagText ".") in
                 (bindingL ++ exprL body) |> wrap
             | Expr.TyLambda(_, argtyvs, body, _, _) -> 
                 ((wordL(tagText "LAM")    ^^ spaceListL (List.map typarL       argtyvs) ^^ rightL(tagText ".")) ++ exprL body) |> wrap
@@ -3727,7 +3727,7 @@ module DebugPrint = begin
             | Expr.Obj (_lambdaId, ty, basev, ccall, overrides, iimpls, _)              -> 
                 wordL(tagText "OBJ:") ^^ aboveListL [typeL ty;
                                             exprL ccall;
-                                            optionL vspecAtBindL basev;
+                                            optionL valAtBindL basev;
                                             aboveListL (List.map overrideL overrides);
                                             aboveListL (List.map iimplL iimpls)]
 
@@ -3812,7 +3812,7 @@ module DebugPrint = begin
     and tmethodL (TObjExprMethod(TSlotSig(nm, _, _, _, _, _), _, tps, vs, e, _)) =
         (wordL(tagText "TObjExprMethod") --- (wordL (tagText nm)) ^^ wordL(tagText "=")) --
           (wordL(tagText "METH-LAM") --- angleBracketListL (List.map typarL       tps) ^^ rightL(tagText ".")) ---
-          (wordL(tagText "meth-lam") --- tupleL (List.map (List.map vspecAtBindL >> tupleL) vs)  ^^ rightL(tagText ".")) ---
+          (wordL(tagText "meth-lam") --- tupleL (List.map (List.map valAtBindL >> tupleL) vs)  ^^ rightL(tagText ".")) ---
           (atomL e) 
     and overrideL tmeth     = wordL(tagText "with") ^^ tmethodL tmeth 
     and iimplL (ty, tmeths) = wordL(tagText "impl") ^^ aboveListL (typeL ty :: List.map tmethodL tmeths) 
@@ -3850,33 +3850,33 @@ let SigTypeOfImplFile (TImplFile(_, _, mexpr, _, _, _)) = mexpr.Type
 //--------------------------------------------------------------------------
 
 type SignatureRepackageInfo = 
-    { mrpiVals  : (ValRef * ValRef) list;
-      mrpiEntities: (TyconRef * TyconRef) list  }
+    { RepackagedVals  : (ValRef * ValRef) list;
+      RepackagedEntities: (TyconRef * TyconRef) list  }
     
-    member remapInfo.ImplToSigMapping = { TypeEquivEnv.Empty with EquivTycons = TyconRefMap.OfList remapInfo.mrpiEntities }
-    static member Empty = { mrpiVals = []; mrpiEntities= [] } 
+    member remapInfo.ImplToSigMapping = { TypeEquivEnv.Empty with EquivTycons = TyconRefMap.OfList remapInfo.RepackagedEntities }
+    static member Empty = { RepackagedVals = []; RepackagedEntities= [] } 
 
 type SignatureHidingInfo = 
-    { mhiTycons     : Zset<Tycon>; 
-      mhiTyconReprs : Zset<Tycon>;  
-      mhiVals       : Zset<Val>; 
-      mhiRecdFields : Zset<RecdFieldRef>; 
-      mhiUnionCases : Zset<UnionCaseRef> }
+    { HiddenTycons     : Zset<Tycon>; 
+      HiddenTyconReprs : Zset<Tycon>;  
+      HiddenVals       : Zset<Val>; 
+      HiddenRecdFields : Zset<RecdFieldRef>; 
+      HiddenUnionCases : Zset<UnionCaseRef> }
 
     static member Empty = 
-        { mhiTycons      = Zset.empty tyconOrder; 
-          mhiTyconReprs  = Zset.empty tyconOrder;  
-          mhiVals        = Zset.empty valOrder; 
-          mhiRecdFields  = Zset.empty recdFieldRefOrder; 
-          mhiUnionCases  = Zset.empty unionCaseRefOrder }
+        { HiddenTycons      = Zset.empty tyconOrder; 
+          HiddenTyconReprs  = Zset.empty tyconOrder;  
+          HiddenVals        = Zset.empty valOrder; 
+          HiddenRecdFields  = Zset.empty recdFieldRefOrder; 
+          HiddenUnionCases  = Zset.empty unionCaseRefOrder }
 
 let addValRemap v v' tmenv = 
     { tmenv with valRemap= tmenv.valRemap.Add v (mkLocalValRef v')  }
 
 let mkRepackageRemapping mrpi = 
-    { valRemap = ValMap.OfList (mrpi.mrpiVals |> List.map (fun (vref, x) -> vref.Deref, x));
+    { valRemap = ValMap.OfList (mrpi.RepackagedVals |> List.map (fun (vref, x) -> vref.Deref, x));
       tpinst = emptyTyparInst; 
-      tyconRefRemap = TyconRefMap.OfList mrpi.mrpiEntities
+      tyconRefRemap = TyconRefMap.OfList mrpi.RepackagedEntities
       removeTraitSolutions = false }
 
 //--------------------------------------------------------------------------
@@ -3888,18 +3888,18 @@ let accEntityRemap (msigty:ModuleOrNamespaceType) (entity:Entity) (mrpi, mhi) =
     match sigtyconOpt with 
     | None -> 
         // The type constructor is not present in the signature. Hence it is hidden. 
-        let mhi = { mhi with mhiTycons = Zset.add entity mhi.mhiTycons }
+        let mhi = { mhi with HiddenTycons = Zset.add entity mhi.HiddenTycons }
         (mrpi, mhi) 
     | Some sigtycon  -> 
         // The type constructor is in the signature. Hence record the repackage entry 
         let sigtcref = mkLocalTyconRef sigtycon
         let tcref = mkLocalTyconRef entity
-        let mrpi = { mrpi with mrpiEntities = ((tcref, sigtcref) :: mrpi.mrpiEntities) }
+        let mrpi = { mrpi with RepackagedEntities = ((tcref, sigtcref) :: mrpi.RepackagedEntities) }
         // OK, now look for hidden things 
         let mhi = 
             if (match entity.TypeReprInfo with TNoRepr -> false | _ -> true) && (match sigtycon.TypeReprInfo with TNoRepr -> true | _ -> false) then 
                 // The type representation is absent in the signature, hence it is hidden 
-                { mhi with mhiTyconReprs = Zset.add entity mhi.mhiTyconReprs } 
+                { mhi with HiddenTyconReprs = Zset.add entity mhi.HiddenTyconReprs } 
             else 
                 // The type representation is present in the signature. 
                 // Find the fields that have been hidden or which were non-public anyway. 
@@ -3912,7 +3912,7 @@ let accEntityRemap (msigty:ModuleOrNamespaceType) (entity:Entity) (mrpi, mhi) =
                             | _ -> 
                                 // The field is not in the signature. Hence it is regarded as hidden. 
                                 let rfref = tcref.MakeNestedRecdFieldRef rfield
-                                { mhi with mhiRecdFields =  Zset.add rfref mhi.mhiRecdFields })
+                                { mhi with HiddenRecdFields =  Zset.add rfref mhi.HiddenRecdFields })
                         entity.AllFieldsArray
                 |> List.foldBack  (fun (ucase:UnionCase) mhi ->
                             match sigtycon.GetUnionCaseByName ucase.DisplayName with 
@@ -3922,7 +3922,7 @@ let accEntityRemap (msigty:ModuleOrNamespaceType) (entity:Entity) (mrpi, mhi) =
                             | _ -> 
                                 // The constructor is not in the signature. Hence it is regarded as hidden. 
                                 let ucref = tcref.MakeNestedUnionCaseRef ucase
-                                { mhi with mhiUnionCases =  Zset.add ucref mhi.mhiUnionCases })
+                                { mhi with HiddenUnionCases =  Zset.add ucref mhi.HiddenUnionCases })
                         (entity.UnionCasesAsList)  
         (mrpi, mhi) 
 
@@ -3931,13 +3931,13 @@ let accSubEntityRemap (msigty:ModuleOrNamespaceType) (entity:Entity) (mrpi, mhi)
     match sigtyconOpt with 
     | None -> 
         // The type constructor is not present in the signature. Hence it is hidden. 
-        let mhi = { mhi with mhiTycons = Zset.add entity mhi.mhiTycons }
+        let mhi = { mhi with HiddenTycons = Zset.add entity mhi.HiddenTycons }
         (mrpi, mhi) 
     | Some sigtycon  -> 
         // The type constructor is in the signature. Hence record the repackage entry 
         let sigtcref = mkLocalTyconRef sigtycon
         let tcref = mkLocalTyconRef entity
-        let mrpi = { mrpi with mrpiEntities = ((tcref, sigtcref) :: mrpi.mrpiEntities) }
+        let mrpi = { mrpi with RepackagedEntities = ((tcref, sigtcref) :: mrpi.RepackagedEntities) }
         (mrpi, mhi) 
 
 let valLinkageAEquiv g aenv (v1:Val) (v2:Val) = 
@@ -3955,11 +3955,11 @@ let accValRemap g aenv (msigty:ModuleOrNamespaceType) (implVal:Val) (mrpi, mhi)
     match sigValOpt with 
     | None -> 
         if verbose then dprintf "accValRemap, hide = %s#%d\n" implVal.LogicalName implVal.Stamp
-        let mhi = { mhi with mhiVals = Zset.add implVal mhi.mhiVals }
+        let mhi = { mhi with HiddenVals = Zset.add implVal mhi.HiddenVals }
         (mrpi, mhi) 
     | Some (sigVal:Val)  -> 
         // The value is in the signature. Add the repackage entry. 
-        let mrpi = { mrpi with mrpiVals = (vref, mkLocalValRef sigVal) :: mrpi.mrpiVals }
+        let mrpi = { mrpi with RepackagedVals = (vref, mkLocalValRef sigVal) :: mrpi.RepackagedVals }
         (mrpi, mhi) 
 
 let getCorrespondingSigTy nm (msigty:ModuleOrNamespaceType) = 
@@ -4053,9 +4053,9 @@ let ComputeRemappingFromImplementationToSignature g mdef msigty =
 let accTyconHidingInfoAtAssemblyBoundary (tycon:Tycon) mhi =
     if not (canAccessFromEverywhere tycon.Accessibility) then 
         // The type constructor is not public, hence hidden at the assembly boundary. 
-        { mhi with mhiTycons = Zset.add tycon mhi.mhiTycons } 
+        { mhi with HiddenTycons = Zset.add tycon mhi.HiddenTycons } 
     elif not (canAccessFromEverywhere tycon.TypeReprAccessibility) then 
-        { mhi with mhiTyconReprs = Zset.add tycon mhi.mhiTyconReprs } 
+        { mhi with HiddenTyconReprs = Zset.add tycon mhi.HiddenTyconReprs } 
     else 
         mhi 
         |> Array.foldBack  
@@ -4063,7 +4063,7 @@ let accTyconHidingInfoAtAssemblyBoundary (tycon:Tycon) mhi =
                    if not (canAccessFromEverywhere rfield.Accessibility) then 
                        let tcref = mkLocalTyconRef tycon
                        let rfref = tcref.MakeNestedRecdFieldRef rfield
-                       { mhi with mhiRecdFields = Zset.add rfref mhi.mhiRecdFields } 
+                       { mhi with HiddenRecdFields = Zset.add rfref mhi.HiddenRecdFields } 
                    else mhi)
                tycon.AllFieldsArray  
         |> List.foldBack  
@@ -4071,7 +4071,7 @@ let accTyconHidingInfoAtAssemblyBoundary (tycon:Tycon) mhi =
                    if not (canAccessFromEverywhere ucase.Accessibility) then 
                        let tcref = mkLocalTyconRef tycon
                        let ucref = tcref.MakeNestedUnionCaseRef ucase
-                       { mhi with mhiUnionCases = Zset.add ucref mhi.mhiUnionCases } 
+                       { mhi with HiddenUnionCases = Zset.add ucref mhi.HiddenUnionCases } 
                    else mhi)
                (tycon.UnionCasesAsList)   
 
@@ -4086,7 +4086,7 @@ let accValHidingInfoAtAssemblyBoundary (vspec:Val) mhi =
        // anything that's not a module or member binding gets assembly visibility
        not vspec.IsMemberOrModuleBinding then 
         // The value is not public, hence hidden at the assembly boundary. 
-        { mhi with mhiVals = Zset.add vspec mhi.mhiVals } 
+        { mhi with HiddenVals = Zset.add vspec mhi.HiddenVals } 
     else 
         mhi
 
@@ -4121,10 +4121,10 @@ let IsHidden setF accessF remapF debugF =
         if verbose then dprintf "IsHidden, #mrmi = %d, %s = %b\n" mrmi.Length (showL (debugF x)) res;
         res
         
-let IsHiddenTycon     mrmi x = IsHidden (fun mhi -> mhi.mhiTycons)     (fun tc -> tc.Accessibility)        (fun rpi x ->  (remapTyconRef rpi.tyconRefRemap (mkLocalTyconRef x)).Deref) DebugPrint.tyconL mrmi x 
-let IsHiddenTyconRepr mrmi x = IsHidden (fun mhi -> mhi.mhiTyconReprs) (fun v -> v.TypeReprAccessibility)  (fun rpi x ->  (remapTyconRef rpi.tyconRefRemap (mkLocalTyconRef x)).Deref) DebugPrint.tyconL mrmi x 
-let IsHiddenVal       mrmi x = IsHidden (fun mhi -> mhi.mhiVals)       (fun v -> v.Accessibility)          (fun rpi x ->  (remapValRef rpi (mkLocalValRef x)).Deref) DebugPrint.valL mrmi x 
-let IsHiddenRecdField mrmi x = IsHidden (fun mhi -> mhi.mhiRecdFields) (fun rfref -> rfref.RecdField.Accessibility) (fun rpi x ->  remapRecdFieldRef rpi.tyconRefRemap x) DebugPrint.recdFieldRefL mrmi x 
+let IsHiddenTycon     mrmi x = IsHidden (fun mhi -> mhi.HiddenTycons)     (fun tc -> tc.Accessibility)        (fun rpi x ->  (remapTyconRef rpi.tyconRefRemap (mkLocalTyconRef x)).Deref) DebugPrint.tyconL mrmi x 
+let IsHiddenTyconRepr mrmi x = IsHidden (fun mhi -> mhi.HiddenTyconReprs) (fun v -> v.TypeReprAccessibility)  (fun rpi x ->  (remapTyconRef rpi.tyconRefRemap (mkLocalTyconRef x)).Deref) DebugPrint.tyconL mrmi x 
+let IsHiddenVal       mrmi x = IsHidden (fun mhi -> mhi.HiddenVals)       (fun v -> v.Accessibility)          (fun rpi x ->  (remapValRef rpi (mkLocalValRef x)).Deref) DebugPrint.valL mrmi x 
+let IsHiddenRecdField mrmi x = IsHidden (fun mhi -> mhi.HiddenRecdFields) (fun rfref -> rfref.RecdField.Accessibility) (fun rpi x ->  remapRecdFieldRef rpi.tyconRefRemap x) DebugPrint.recdFieldRefL mrmi x 
 
 
 //--------------------------------------------------------------------------
diff --git a/src/fsharp/TastOps.fsi b/src/fsharp/TastOps.fsi
index 0731970c195..badacfda0ea 100755
--- a/src/fsharp/TastOps.fsi
+++ b/src/fsharp/TastOps.fsi
@@ -3,26 +3,18 @@
 /// Defines derived expression manipulation and construction functions.
 module internal Microsoft.FSharp.Compiler.Tastops 
 
-open System.Text
 open System.Collections.Generic
 open Internal.Utilities
 open Microsoft.FSharp.Compiler.AbstractIL 
 open Microsoft.FSharp.Compiler.AbstractIL.IL 
 open Microsoft.FSharp.Compiler.AbstractIL.Internal 
-open Microsoft.FSharp.Compiler.AbstractIL.Internal.Library
 open Microsoft.FSharp.Compiler 
 open Microsoft.FSharp.Compiler.Range
 open Microsoft.FSharp.Compiler.Rational
 open Microsoft.FSharp.Compiler.Ast
-open Microsoft.FSharp.Compiler.ErrorLogger
 open Microsoft.FSharp.Compiler.Tast
 open Microsoft.FSharp.Compiler.TcGlobals
 open Microsoft.FSharp.Compiler.Layout
-open Microsoft.FSharp.Compiler.Lib
-
-#if !NO_EXTENSIONTYPING
-open Microsoft.FSharp.Compiler.ExtensionTyping
-#endif
 
 //-------------------------------------------------------------------------
 // Type equivalence
@@ -42,10 +34,6 @@ val measureEquiv    :            TcGlobals  -> Measure  -> Measure -> bool
 /// Reduce a type to its more anonical form subject to an erasure flag, inference equations and abbreviations
 val stripTyEqnsWrtErasure: Erasure -> TcGlobals -> TType -> TType
 
-//-------------------------------------------------------------------------
-// Build common types
-//------------------------------------------------------------------------- 
-
 /// Build a function type
 val mkFunTy : TType -> TType -> TType
 
@@ -77,139 +65,232 @@ val stripExpr : Expr -> Expr
 
 /// Get the values for a set of bindings
 val valsOfBinds : Bindings -> Vals 
-val (|ExprValWithPossibleTypeInst|_|) : Expr -> (ValRef * ValUseFlag * TType list * range) option
 
-//-------------------------------------------------------------------------
-// Build decision trees imperatively
-//------------------------------------------------------------------------- 
+/// Look for a use of an F# value, possibly including application of a generic thing to a set of type arguments
+val (|ExprValWithPossibleTypeInst|_|) : Expr -> (ValRef * ValUseFlag * TType list * range) option
 
+/// Build decision trees imperatively
 type MatchBuilder =
+
+    /// Create a new builder
     new : SequencePointInfoForBinding * range -> MatchBuilder
+
+    /// Add a new destination target
     member AddTarget : DecisionTreeTarget -> int
+
+    /// Add a new destination target that is an expression result
     member AddResultTarget : Expr * SequencePointInfoForTarget -> DecisionTree
+
+    /// Finish the targets
     member CloseTargets : unit -> DecisionTreeTarget list
-    member Close : DecisionTree * range * TType -> Expr
 
-//-------------------------------------------------------------------------
-// Make some special decision graphs
-//------------------------------------------------------------------------- 
+    /// Build the overall expression
+    member Close : DecisionTree * range * TType -> Expr
 
+/// Add an if-then-else boolean conditional node into a decision tree
 val mkBoolSwitch : range -> Expr -> DecisionTree -> DecisionTree -> DecisionTree
+
+/// Build a conditional expression
 val primMkCond : SequencePointInfoForBinding -> SequencePointInfoForTarget -> SequencePointInfoForTarget -> range -> TType -> Expr -> Expr -> Expr -> Expr
+
+/// Build a conditional expression
 val mkCond : SequencePointInfoForBinding -> SequencePointInfoForTarget -> range -> TType -> Expr -> Expr -> Expr -> Expr
+
+/// Build a conditional expression that checks for non-nullness
 val mkNonNullCond : TcGlobals -> range -> TType -> Expr -> Expr -> Expr -> Expr
-val mkIfThen : TcGlobals -> range -> Expr -> Expr -> Expr 
 
-//-------------------------------------------------------------------------
-// Generate new locals
-//------------------------------------------------------------------------- 
+/// Build an if-then statement
+val mkIfThen : TcGlobals -> range -> Expr -> Expr -> Expr 
 
+/// Build an expression corresponding to the use of a value
 /// Note: try to use exprForValRef or the expression returned from mkLocal instead of this. 
 val exprForVal : range -> Val -> Expr
+
+/// Build an expression corresponding to the use of a reference to a value
 val exprForValRef : range -> ValRef -> Expr
 
-/// Return the local and an expression to reference it
+/// Make a new local value and build an expression to reference it
 val mkLocal : range -> string -> TType -> Val * Expr
+
+/// Make a new compiler-generated local value and build an expression to reference it
 val mkCompGenLocal : range -> string -> TType -> Val * Expr
+
+/// Make a new mutable compiler-generated local value and build an expression to reference it
 val mkMutableCompGenLocal : range -> string -> TType -> Val * Expr
-val mkCompGenLocalAndInvisbleBind : TcGlobals -> string -> range -> Expr -> Val * Expr * Binding 
 
-//-------------------------------------------------------------------------
-// Make lambdas
-//------------------------------------------------------------------------- 
+/// Make a new mutable compiler-generated local value, 'let' bind it to an expression 
+/// 'invisibly' (no sequence point etc.), and build an expression to reference it
+val mkCompGenLocalAndInvisbleBind : TcGlobals -> string -> range -> Expr -> Val * Expr * Binding 
 
+/// Build a lambda expression taking multiple values
 val mkMultiLambda : range -> Val list -> Expr * TType -> Expr
+
+/// Rebuild a lambda during an expression tree traversal
 val rebuildLambda : range -> Val option -> Val option -> Val list -> Expr * TType -> Expr
+
+/// Build a lambda expression taking a single value 
 val mkLambda : range -> Val -> Expr * TType -> Expr
+
+/// Build a generic lambda expression (type abstraction)
 val mkTypeLambda : range -> Typars -> Expr * TType -> Expr
+
+/// Build an object expression
 val mkObjExpr : TType * Val option * Expr * ObjExprMethod list * (TType * ObjExprMethod list) list * Range.range -> Expr
+
+/// Build an type-chose expression, indicating that a local free choice of a type variable
 val mkTypeChoose : range -> Typars -> Expr -> Expr
+
+/// Build an iterated (curried) lambda expression
 val mkLambdas : range -> Typars -> Val list -> Expr * TType -> Expr
+
+/// Build an iterated (tupled+curried) lambda expression
 val mkMultiLambdasCore : range -> Val list list -> Expr * TType -> Expr * TType
+
+/// Build an iterated generic (type abstraction + tupled+curried) lambda expression
 val mkMultiLambdas : range -> Typars -> Val list list -> Expr * TType -> Expr
+
+/// Build a lambda expression that corresponds to the implementation of a member
 val mkMemberLambdas : range -> Typars -> Val option -> Val option -> Val list list -> Expr * TType -> Expr
 
+/// Build a 'while' loop expression
 val mkWhile      : TcGlobals -> SequencePointInfoForWhileLoop * SpecialWhileLoopMarker * Expr * Expr * range                          -> Expr
+
+/// Build a 'for' loop expression
 val mkFor        : TcGlobals -> SequencePointInfoForForLoop * Val * Expr * ForLoopStyle * Expr * Expr * range -> Expr
+
+/// Build a 'try/with' expression
 val mkTryWith  : TcGlobals -> Expr * (* filter val *) Val * (* filter expr *) Expr * (* handler val *) Val * (* handler expr *) Expr * range * TType * SequencePointInfoForTry * SequencePointInfoForWith -> Expr
-val mkTryFinally: TcGlobals -> Expr * Expr * range * TType * SequencePointInfoForTry * SequencePointInfoForFinally -> Expr
 
-//-------------------------------------------------------------------------
-// Make let/letrec
-//------------------------------------------------------------------------- 
- 
+/// Build a 'try/finally' expression
+val mkTryFinally: TcGlobals -> Expr * Expr * range * TType * SequencePointInfoForTry * SequencePointInfoForFinally -> Expr
 
-// Generate a user-level let-bindings
+/// Build a user-level value binding
 val mkBind : SequencePointInfoForBinding -> Val -> Expr -> Binding
+
+/// Build a user-level let-binding
 val mkLetBind : range -> Binding -> Expr -> Expr
+
+/// Build a user-level value sequence of let bindings
 val mkLetsBind : range -> Binding list -> Expr -> Expr
+
+/// Build a user-level value sequence of let bindings
 val mkLetsFromBindings : range -> Bindings -> Expr -> Expr
+
+/// Build a user-level let expression
 val mkLet : SequencePointInfoForBinding -> range -> Val -> Expr -> Expr -> Expr
+
+/// Make a binding that binds a function value to a lambda taking multiple arguments
 val mkMultiLambdaBind : Val -> SequencePointInfoForBinding -> range -> Typars -> Val list list -> Expr * TType -> Binding
 
 // Compiler generated bindings may involve a user variable.
 // Compiler generated bindings may give rise to a sequence point if they are part of
 // an SPAlways expression. Compiler generated bindings can arise from for example, inlining.
 val mkCompGenBind : Val -> Expr -> Binding
+
+/// Make a set of bindings that bind compiler generated values to corresponding expressions.
+/// Compiler-generated bindings do not give rise to a sequence point in debugging.
 val mkCompGenBinds : Val list -> Exprs -> Bindings
+
+/// Make a let-expression that locally binds a compiler-generated value to an expression.
+/// Compiler-generated bindings do not give rise to a sequence point in debugging.
 val mkCompGenLet : range -> Val -> Expr -> Expr -> Expr
+
+/// Make a let-expression that locally binds a compiler-generated value to an expression, where the expression
+/// is returned by the given continuation. Compiler-generated bindings do not give rise to a sequence point in debugging.
 val mkCompGenLetIn: range -> string -> TType -> Expr -> (Val * Expr -> Expr) -> Expr
 
-// Invisible bindings are never given a sequence point and should never have side effects
+/// Make a let-expression that locally binds a value to an expression in an "invisible" way.
+/// Invisible bindings are not given a sequence point and should not have side effects.
 val mkInvisibleLet : range -> Val -> Expr -> Expr -> Expr
+
+/// Make a binding that binds a value to an expression in an "invisible" way.
+/// Invisible bindings are not given a sequence point and should not have side effects.
 val mkInvisibleBind : Val -> Expr -> Binding
+
+/// Make a set of bindings that bind values to expressions in an "invisible" way.
+/// Invisible bindings are not given a sequence point and should not have side effects.
 val mkInvisibleBinds : Vals -> Exprs -> Bindings
+
+/// Make a let-rec expression that locally binds values to expressions where self-reference back to the values is possible.
 val mkLetRecBinds : range -> Bindings -> Expr -> Expr
  
-//-------------------------------------------------------------------------
-// Generalization/inference helpers
-//------------------------------------------------------------------------- 
- 
 /// TypeScheme (generalizedTypars, tauTy)
 ///
 ///    generalizedTypars -- the truly generalized type parameters 
 ///    tauTy  --  the body of the generalized type. A 'tau' type is one with its type parameters stripped off.
 type TypeScheme = TypeScheme of Typars  * TType    
 
+/// Make the right-hand side of a generalized binding, incorporating the generalized generic parameters from the type
+/// scheme into the right-hand side as type generalizations.
 val mkGenericBindRhs : TcGlobals -> range -> Typars -> TypeScheme -> Expr -> Expr
-val isBeingGeneralized : Typar -> TypeScheme -> bool
 
-//-------------------------------------------------------------------------
-// Make lazy and/or
-//------------------------------------------------------------------------- 
+/// Test if the type parameter is one of those being generalized by a type scheme.
+val isBeingGeneralized : Typar -> TypeScheme -> bool
 
+/// Make the expression corresponding to 'expr1 && expr2'
 val mkLazyAnd  : TcGlobals -> range -> Expr -> Expr -> Expr
+
+/// Make the expression corresponding to 'expr1 || expr2'
 val mkLazyOr   : TcGlobals -> range -> Expr -> Expr -> Expr
+
+/// Make a byref type 
 val mkByrefTy  : TcGlobals -> TType -> TType
+
+/// Make a byref type with a in/out kind inference parameter
 val mkByrefTyWithInference  : TcGlobals -> TType -> TType -> TType
+
+/// Make a in-byref type with a in kind parameter
 val mkInByrefTy  : TcGlobals -> TType -> TType
-val mkOutByrefTy  : TcGlobals -> TType -> TType
 
-//-------------------------------------------------------------------------
-// Make construction operations
-//------------------------------------------------------------------------- 
+/// Make an out-byref type with an out kind parameter
+val mkOutByrefTy  : TcGlobals -> TType -> TType
 
+/// Make an expression that constructs a union case, e.g. 'Some(expr)'
 val mkUnionCaseExpr : UnionCaseRef * TypeInst * Exprs * range -> Expr
+
+/// Make an expression that constructs an exception value
 val mkExnExpr : TyconRef * Exprs * range -> Expr
+
+/// Make an expression that is IL assembly code
 val mkAsmExpr : ILInstr list * TypeInst * Exprs * TTypes * range -> Expr
+
+/// Make an expression that coerces one expression to another type
 val mkCoerceExpr : Expr * TType * range * TType -> Expr
-val mkReraise : range -> TType -> Expr
-val mkReraiseLibCall : TcGlobals -> TType -> range -> Expr
 
+/// Make an expression that re-raises an exception
+val mkReraise : range -> TType -> Expr
 
-//-------------------------------------------------------------------------
-// Make projection operations
-//------------------------------------------------------------------------- 
+/// Make an expression that re-raises an exception via a library call
+val mkReraiseLibCall : TcGlobals -> TType -> range -> Expr
  
+/// Make an expression that gets an item from a tuple
 val mkTupleFieldGet                : TcGlobals -> TupInfo * Expr * TypeInst * int * range -> Expr
+
+/// Make an expression that gets an item from an anonymous record
 val mkAnonRecdFieldGet             : TcGlobals -> AnonRecdTypeInfo * Expr * TypeInst * int * range -> Expr
+
+/// Make an expression that gets an item from an anonymous record (via the address of the value if it is a struct)
 val mkAnonRecdFieldGetViaExprAddr  : AnonRecdTypeInfo * Expr * TypeInst * int * range -> Expr
+
+/// Make an expression that gets an instance field from a record or class (via the address of the value if it is a struct)
 val mkRecdFieldGetViaExprAddr      :                  Expr * RecdFieldRef   * TypeInst               * range -> Expr
+
+/// Make an expression that gets the address of an instance field from a record or class (via the address of the value if it is a struct)
 val mkRecdFieldGetAddrViaExprAddr  : readonly: bool * Expr * RecdFieldRef   * TypeInst               * range -> Expr
+
+/// Make an expression that gets a static field from a record or class 
 val mkStaticRecdFieldGet           :                         RecdFieldRef   * TypeInst               * range -> Expr
+
+/// Make an expression that sets a static field in a record or class 
 val mkStaticRecdFieldSet           :                         RecdFieldRef   * TypeInst * Expr        * range -> Expr
+
+/// Make an expression that gets the address of a static field in a record or class 
 val mkStaticRecdFieldGetAddr       : readonly: bool *        RecdFieldRef   * TypeInst               * range -> Expr
+
+/// Make an expression that sets an instance the field of a record or class (via the address of the value if it is a struct)
 val mkRecdFieldSetViaExprAddr      :                  Expr * RecdFieldRef   * TypeInst * Expr        * range -> Expr
+
+/// Make an expression that gets the tag of a union value (via the address of the value if it is a struct)
 val mkUnionCaseTagGetViaExprAddr   : Expr * TyconRef       * TypeInst               * range -> Expr
 
 /// Make a 'TOp.UnionCaseProof' expression, which proves a union value is over a particular case (used only for ref-unions, not struct-unions)
@@ -238,9 +319,13 @@ val mkUnionCaseFieldSet            : Expr * UnionCaseRef   * TypeInst * int  * E
 /// Like mkUnionCaseFieldGetUnprovenViaExprAddr, but for struct-unions, the input should be a copy of the expression.
 val mkUnionCaseFieldGetUnproven    : TcGlobals -> Expr * UnionCaseRef   * TypeInst * int         * range -> Expr
 
+/// Make an expression that gets an instance field from an F# exception value 
 val mkExnCaseFieldGet              : Expr * TyconRef               * int         * range -> Expr
+
+/// Make an expression that sets an instance field in an F# exception value 
 val mkExnCaseFieldSet              : Expr * TyconRef               * int  * Expr * range -> Expr
 
+/// Make an expression that gets the address of an element in an array
 val mkArrayElemAddress : TcGlobals -> readonly: bool * ILReadonly * bool * ILArrayShape * TType * Expr list * range -> Expr
 
 //-------------------------------------------------------------------------
@@ -272,49 +357,60 @@ val mkGetTupleItemN : TcGlobals -> range -> int -> ILType -> bool -> Expr -> TTy
 /// Evaluate the TupInfo to work out if it is a struct or a ref.  Currently this is very simple
 /// but TupInfo may later be used carry variables that infer structness.
 val evalTupInfoIsStruct : TupInfo -> bool
+
+/// Evaluate the AnonRecdTypeInfo to work out if it is a struct or a ref. 
 val evalAnonInfoIsStruct : AnonRecdTypeInfo -> bool
 
 /// If it is a tuple type, ensure it's outermost type is a .NET tuple type, otherwise leave unchanged
 val convertToTypeWithMetadataIfPossible : TcGlobals -> TType -> TType
 
-
-//-------------------------------------------------------------------------
-// Take the address of an expression, or force it into a mutable local. Any allocated
-// mutable local may need to be kept alive over a larger expression, hence we return
-// a wrapping function that wraps "let mutable loc = Expr in ..." around a larger
-// expression.
-//------------------------------------------------------------------------- 
-
+/// An exception representing a warning for a defensive copy of an immutable struct
 exception DefensiveCopyWarning of string * range 
+
 type Mutates = AddressOfOp | DefinitelyMutates | PossiblyMutates | NeverMutates
+
+/// Helper to take the address of an expression
 val mkExprAddrOfExprAux : TcGlobals -> bool -> bool -> Mutates -> Expr -> ValRef option -> range -> (Val * Expr) option * Expr * bool * bool
-val mkExprAddrOfExpr : TcGlobals -> bool -> bool -> Mutates -> Expr -> ValRef option -> range -> (Expr -> Expr) * Expr * bool * bool
 
-//-------------------------------------------------------------------------
-// Tables keyed on values and/or type parameters
-//------------------------------------------------------------------------- 
+/// Take the address of an expression, or force it into a mutable local. Any allocated
+/// mutable local may need to be kept alive over a larger expression, hence we return
+/// a wrapping function that wraps "let mutable loc = Expr in ..." around a larger
+/// expression.
+val mkExprAddrOfExpr : TcGlobals -> bool -> bool -> Mutates -> Expr -> ValRef option -> range -> (Expr -> Expr) * Expr * bool * bool
 
 /// Maps Val to T, based on stamps
 [<Struct;NoEquality; NoComparison>]
 type ValMap<'T> = 
+
     member Contents : StampMap<'T>
+
     member Item : Val -> 'T with get
+
     member TryFind : Val -> 'T option
+
     member ContainsVal : Val -> bool
+
     member Add : Val -> 'T -> ValMap<'T>
+
     member Remove : Val -> ValMap<'T>
+
     member IsEmpty : bool
+
     static member Empty : ValMap<'T>
+
     static member OfList : (Val * 'T) list -> ValMap<'T>
 
 /// Mutable data structure mapping Val's to T based on stamp keys
 [<Sealed; NoEquality; NoComparison>]
 type ValHash<'T> =
+
     member Values : seq<'T>
+
     member TryFind : Val -> 'T option
+
     member Add : Val * 'T -> unit
-    static member Create : unit -> ValHash<'T>
 
+    static member Create : unit -> ValHash<'T>
 
 /// Maps Val's to list of T based on stamp keys
 [<Struct; NoEquality; NoComparison>]
@@ -332,97 +428,126 @@ type ValMultiMap<'T> =
 
     static member Empty : ValMultiMap<'T>
 
+/// Maps type parameters to entries based on stamp keys
 [<Sealed>]
-/// Maps Typar to T based on stamp keys
 type TyparMap<'T>  =
 
+    /// Get the entry for the given type parameter
     member Item : Typar -> 'T with get
 
+    /// Determine is the map contains an entry for the given type parameter
     member ContainsKey : Typar -> bool
 
+    /// Try to find the entry for the given type parameter
     member TryFind : Typar -> 'T option
 
+    /// Make a new map, containing a new entry for the given type parameter
     member Add : Typar * 'T -> TyparMap<'T> 
 
+    /// The empty map
     static member Empty : TyparMap<'T> 
 
-[<NoEquality; NoComparison;Sealed>]
 /// Maps TyconRef to T based on stamp keys
+[<NoEquality; NoComparison; Sealed>]
 type TyconRefMap<'T> =
 
+    /// Get the entry for the given type definition
     member Item : TyconRef -> 'T with get
 
+    /// Try to find the entry for the given type definition
     member TryFind : TyconRef -> 'T option
 
+    /// Determine is the map contains an entry for the given type definition
     member ContainsKey : TyconRef -> bool
 
+    /// Make a new map, containing a new entry for the given type definition
     member Add : TyconRef -> 'T -> TyconRefMap<'T>
 
+    /// Remove the entry for the given type definition, if any
     member Remove : TyconRef -> TyconRefMap<'T>
 
+    /// Determine if the map is empty
     member IsEmpty : bool
 
+    /// The empty map
     static member Empty : TyconRefMap<'T>
 
+    /// Make a new map, containing entries for the given type definitions
     static member OfList : (TyconRef * 'T) list -> TyconRefMap<'T>
 
 /// Maps TyconRef to list of T based on stamp keys
 [<Struct; NoEquality; NoComparison>]
 type TyconRefMultiMap<'T> =
 
+    /// Fetch the entries for the given type definition
     member Find : TyconRef -> 'T list
 
+    /// Make a new map, containing a new entry for the given type definition
     member Add : TyconRef * 'T -> TyconRefMultiMap<'T>
 
+    /// The empty map
     static member Empty : TyconRefMultiMap<'T>
 
+    /// Make a new map, containing a entries for the given type definitions
     static member OfList : (TyconRef * 'T) list -> TyconRefMultiMap<'T>
 
-//-------------------------------------------------------------------------
-// Orderings on Tycon, Val, RecdFieldRef, Typar
-//------------------------------------------------------------------------- 
+/// An ordering for value definitions, based on stamp
+val valOrder: IComparer<Val>
 
-val valOrder          : IComparer<Val>
-val tyconOrder        : IComparer<Tycon>
-val recdFieldRefOrder : IComparer<RecdFieldRef>
-val typarOrder        : IComparer<Typar>
+/// An ordering for type definitions, based on stamp
+val tyconOrder: IComparer<Tycon>
 
-//-------------------------------------------------------------------------
-// Equality on Tycon and Val
-//------------------------------------------------------------------------- 
+/// An ordering for record fields, based on stamp
+val recdFieldRefOrder: IComparer<RecdFieldRef>
 
+/// An ordering for type parameters, based on stamp
+val typarOrder: IComparer<Typar>
+
+/// Equality for type definition references
 val tyconRefEq : TcGlobals -> TyconRef -> TyconRef -> bool
+
+/// Equality for value references
 val valRefEq : TcGlobals -> ValRef -> ValRef -> bool
 
 //-------------------------------------------------------------------------
 // Operations on types: substitution
 //------------------------------------------------------------------------- 
 
+/// Represents an instantiation where types replace type parameters
 type TyparInst = (Typar * TType) list
 
+/// Represents an instantiation where type definition references replace other type definition references
 type TyconRefRemap = TyconRefMap<TyconRef>
+
+/// Represents an instantiation where value references replace other value references
 type ValRemap = ValMap<ValRef>
 
+/// Represents a combination of substitutions/instantiations where things replace other things during remapping
 [<NoEquality; NoComparison>]
 type Remap =
-    { tpinst : TyparInst;
-      valRemap: ValRemap;
-      tyconRefRemap : TyconRefRemap;
+    { tpinst : TyparInst
+      valRemap: ValRemap
+      tyconRefRemap : TyconRefRemap
       removeTraitSolutions: bool }
 
     static member Empty : Remap
 
 val addTyconRefRemap : TyconRef -> TyconRef -> Remap -> Remap
-val addValRemap : Val -> Val -> Remap -> Remap
 
+val addValRemap : Val -> Val -> Remap -> Remap
 
 val mkTyparInst : Typars -> TTypes -> TyparInst
+
 val mkTyconRefInst : TyconRef -> TypeInst -> TyparInst
+
 val emptyTyparInst : TyparInst
 
 val instType               : TyparInst -> TType -> TType
+
 val instTypes              : TyparInst -> TypeInst -> TypeInst
+
 val instTyparConstraints  : TyparInst -> TyparConstraint list -> TyparConstraint list 
+
 val instTrait              : TyparInst -> TraitConstraintInfo -> TraitConstraintInfo 
 
 //-------------------------------------------------------------------------
@@ -430,8 +555,11 @@ val instTrait              : TyparInst -> TraitConstraintInfo -> TraitConstraint
 //------------------------------------------------------------------------- 
 
 val generalizeTypars : Typars -> TypeInst
+
 val generalizeTyconRef : TyconRef -> TTypes * TType
+
 val generalizedTyconRef : TyconRef -> TType
+
 val mkTyparToTyparRenaming : Typars -> Typars -> TyparInst * TTypes
 
 //-------------------------------------------------------------------------
@@ -439,12 +567,16 @@ val mkTyparToTyparRenaming : Typars -> Typars -> TyparInst * TTypes
 //------------------------------------------------------------------------- 
 
 val reduceTyconRefAbbrev : TyconRef -> TypeInst -> TType
+
 val reduceTyconRefMeasureableOrProvided : TcGlobals -> TyconRef -> TypeInst -> TType
+
 val reduceTyconRefAbbrevMeasureable : TyconRef -> Measure
 
 /// set bool to 'true' to allow shortcutting of type parameter equation chains during stripping 
 val stripTyEqnsA : TcGlobals -> bool -> TType -> TType 
+
 val stripTyEqns : TcGlobals -> TType -> TType
+
 val stripTyEqnsAndMeasureEqns : TcGlobals -> TType -> TType
 
 val tryNormalizeMeasureInType : TcGlobals -> TType -> TType
@@ -455,7 +587,9 @@ val tryNormalizeMeasureInType : TcGlobals -> TType -> TType
 
 /// See through F# exception abbreviations
 val stripExnEqns : TyconRef -> Tycon
+
 val recdFieldsOfExnDefRef : TyconRef -> RecdField list
+
 val recdFieldTysOfExnDefRef : TyconRef -> TType list
 
 //-------------------------------------------------------------------------
@@ -464,63 +598,102 @@ val recdFieldTysOfExnDefRef : TyconRef -> TType list
 //------------------------------------------------------------------------- 
 
 val destForallTy      : TcGlobals -> TType -> Typars * TType
+
 val destFunTy         : TcGlobals -> TType -> TType * TType
+
 val destAnyTupleTy    : TcGlobals -> TType -> TupInfo * TTypes
+
 val destRefTupleTy    : TcGlobals -> TType -> TTypes
+
 val destStructTupleTy : TcGlobals -> TType -> TTypes
+
 val destTyparTy       : TcGlobals -> TType -> Typar
+
 val destAnyParTy      : TcGlobals -> TType -> Typar
+
 val destMeasureTy     : TcGlobals -> TType -> Measure
+
 val tryDestForallTy   : TcGlobals -> TType -> Typars * TType
 
 val isFunTy            : TcGlobals -> TType -> bool
+
 val isForallTy         : TcGlobals -> TType -> bool
+
 val isAnyTupleTy       : TcGlobals -> TType -> bool
+
 val isRefTupleTy       : TcGlobals -> TType -> bool
+
 val isStructTupleTy    : TcGlobals -> TType -> bool
+
 val isStructAnonRecdTy    : TcGlobals -> TType -> bool
+
 val isAnonRecdTy    : TcGlobals -> TType -> bool
+
 val isUnionTy          : TcGlobals -> TType -> bool
+
 val isReprHiddenTy     : TcGlobals -> TType -> bool
+
 val isFSharpObjModelTy : TcGlobals -> TType -> bool
+
 val isRecdTy           : TcGlobals -> TType -> bool
+
 val isFSharpStructOrEnumTy : TcGlobals -> TType -> bool
+
 val isFSharpEnumTy     : TcGlobals -> TType -> bool
+
 val isTyparTy          : TcGlobals -> TType -> bool
+
 val isAnyParTy         : TcGlobals -> TType -> bool
+
 val tryAnyParTy        : TcGlobals -> TType -> ValueOption<Typar>
+
 val tryAnyParTyOption  : TcGlobals -> TType -> Typar option
+
 val isMeasureTy        : TcGlobals -> TType -> bool
 
 val mkAppTy : TyconRef -> TypeInst -> TType
 
 val mkProvenUnionCaseTy : UnionCaseRef -> TypeInst -> TType
+
 val isProvenUnionCaseTy : TType -> bool
 
 val isAppTy        : TcGlobals -> TType -> bool
+
 val tryAppTy       : TcGlobals -> TType -> ValueOption<TyconRef * TypeInst>
+
 val destAppTy      : TcGlobals -> TType -> TyconRef * TypeInst
+
 val tcrefOfAppTy   : TcGlobals -> TType -> TyconRef
+
 val tryDestAppTy   : TcGlobals -> TType -> ValueOption<TyconRef>
+
 val tryDestTyparTy : TcGlobals -> TType -> ValueOption<Typar>
+
 val tryDestFunTy : TcGlobals -> TType -> ValueOption<(TType * TType)>
+
 val tryDestAnonRecdTy : TcGlobals -> TType -> ValueOption<AnonRecdTypeInfo * TType list>
+
 val argsOfAppTy    : TcGlobals -> TType -> TypeInst
+
 val mkInstForAppTy  : TcGlobals -> TType -> TyparInst
 
 /// Try to get a TyconRef for a type without erasing type abbreviations
 val tryNiceEntityRefOfTy : TType -> ValueOption<TyconRef>
-val tryNiceEntityRefOfTyOption : TType -> TyconRef option
 
+val tryNiceEntityRefOfTyOption : TType -> TyconRef option
 
 val domainOfFunTy  : TcGlobals -> TType -> TType
+
 val rangeOfFunTy   : TcGlobals -> TType -> TType
+
 val stripFunTy     : TcGlobals -> TType -> TType list * TType
+
 val stripFunTyN    : TcGlobals -> int -> TType -> TType list * TType
 
 val applyForallTy : TcGlobals -> TType -> TypeInst -> TType
 
 val tryDestAnyTupleTy : TcGlobals -> TType -> TupInfo * TType list
+
 val tryDestRefTupleTy : TcGlobals -> TType -> TType list
 
 //-------------------------------------------------------------------------
@@ -535,7 +708,9 @@ val actualTysOfUnionCaseFields : TyparInst -> UnionCaseRef -> TType list
 val actualTysOfInstanceRecdFields    : TyparInst -> TyconRef -> TType list
 
 val actualTyOfRecdField            : TyparInst -> RecdField -> TType
+
 val actualTyOfRecdFieldRef : RecdFieldRef -> TypeInst -> TType
+
 val actualTyOfRecdFieldForTycon    : Tycon -> TypeInst -> RecdField -> TType
 
 //-------------------------------------------------------------------------
@@ -545,14 +720,21 @@ val actualTyOfRecdFieldForTycon    : Tycon -> TypeInst -> RecdField -> TType
 //------------------------------------------------------------------------- 
 
 type UncurriedArgInfos = (TType * ArgReprInfo) list 
+
 type CurriedArgInfos = UncurriedArgInfos list
 
 val destTopForallTy : TcGlobals -> ValReprInfo -> TType -> Typars * TType 
+
 val GetTopTauTypeInFSharpForm     : TcGlobals -> ArgReprInfo list list -> TType -> range -> CurriedArgInfos * TType
+
 val GetTopValTypeInFSharpForm     : TcGlobals -> ValReprInfo -> TType -> range -> Typars * CurriedArgInfos * TType * ArgReprInfo
+
 val IsCompiledAsStaticProperty    : TcGlobals -> Val -> bool
+
 val IsCompiledAsStaticPropertyWithField : TcGlobals -> Val -> bool
+
 val GetTopValTypeInCompiledForm   : TcGlobals -> ValReprInfo -> TType -> range -> Typars * CurriedArgInfos * TType option * ArgReprInfo
+
 val GetFSharpViewOfReturnType     : TcGlobals -> TType option -> TType
 
 val NormalizeDeclaredTyparsForEquiRecursiveInference : TcGlobals -> Typars -> Typars
@@ -568,40 +750,58 @@ val applyTys : TcGlobals -> TType -> TType list * 'T list -> TType
 //------------------------------------------------------------------------- 
  
 val emptyFreeTypars : FreeTypars
+
 val unionFreeTypars : FreeTypars -> FreeTypars -> FreeTypars
 
 val emptyFreeTycons : FreeTycons
+
 val unionFreeTycons : FreeTycons -> FreeTycons -> FreeTycons
 
 val emptyFreeTyvars : FreeTyvars
+
 val isEmptyFreeTyvars : FreeTyvars -> bool
+
 val unionFreeTyvars : FreeTyvars -> FreeTyvars -> FreeTyvars
 
 val emptyFreeLocals : FreeLocals
+
 val unionFreeLocals : FreeLocals -> FreeLocals -> FreeLocals
 
 type FreeVarOptions 
 
 val CollectLocalsNoCaching : FreeVarOptions
+
 val CollectTyparsNoCaching : FreeVarOptions
+
 val CollectTyparsAndLocalsNoCaching : FreeVarOptions
+
 val CollectTyparsAndLocals : FreeVarOptions
+
 val CollectLocals : FreeVarOptions
+
 val CollectTypars : FreeVarOptions
+
 val CollectAllNoCaching : FreeVarOptions
+
 val CollectAll : FreeVarOptions
 
 val accFreeInTypes : FreeVarOptions -> TType list -> FreeTyvars -> FreeTyvars
+
 val accFreeInType : FreeVarOptions -> TType -> FreeTyvars -> FreeTyvars
+
 val accFreeInTypars : FreeVarOptions -> Typars -> FreeTyvars -> FreeTyvars
 
 val freeInType  : FreeVarOptions -> TType      -> FreeTyvars
+
 val freeInTypes : FreeVarOptions -> TType list -> FreeTyvars
+
 val freeInVal   : FreeVarOptions -> Val -> FreeTyvars
 
 // This one puts free variables in canonical left-to-right order. 
 val freeInTypeLeftToRight : TcGlobals -> bool -> TType -> Typars
+
 val freeInTypesLeftToRight : TcGlobals -> bool -> TType list -> Typars
+
 val freeInTypesLeftToRightSkippingConstraints : TcGlobals -> TType list -> Typars
 
 val freeInModuleTy: ModuleOrNamespaceType -> FreeTyvars
@@ -614,25 +814,39 @@ val isDimensionless : TcGlobals -> TType -> bool
 
 [<NoEquality; NoComparison>]
 type TypeEquivEnv = 
-    { EquivTypars: TyparMap<TType>;
+    { EquivTypars: TyparMap<TType>
       EquivTycons: TyconRefRemap }
 
     static member Empty : TypeEquivEnv
+
     member BindEquivTypars : Typars -> Typars -> TypeEquivEnv
+
     static member FromTyparInst : TyparInst -> TypeEquivEnv
+
     static member FromEquivTypars : Typars -> Typars -> TypeEquivEnv
 
 val traitsAEquivAux           : Erasure -> TcGlobals -> TypeEquivEnv -> TraitConstraintInfo  -> TraitConstraintInfo  -> bool
+
 val traitsAEquiv              :            TcGlobals -> TypeEquivEnv -> TraitConstraintInfo  -> TraitConstraintInfo  -> bool
+
 val typarConstraintsAEquivAux : Erasure -> TcGlobals -> TypeEquivEnv -> TyparConstraint      -> TyparConstraint      -> bool
+
 val typarConstraintsAEquiv    :            TcGlobals -> TypeEquivEnv -> TyparConstraint      -> TyparConstraint      -> bool
+
 val typarsAEquiv              :            TcGlobals -> TypeEquivEnv -> Typars               -> Typars               -> bool
+
 val typeAEquivAux             : Erasure -> TcGlobals -> TypeEquivEnv -> TType                  -> TType                  -> bool
+
 val typeAEquiv                :            TcGlobals -> TypeEquivEnv -> TType                  -> TType                  -> bool
+
 val returnTypesAEquivAux      : Erasure -> TcGlobals -> TypeEquivEnv -> TType option           -> TType option           -> bool
+
 val returnTypesAEquiv         :            TcGlobals -> TypeEquivEnv -> TType option           -> TType option           -> bool
+
 val tcrefAEquiv               :            TcGlobals -> TypeEquivEnv -> TyconRef             -> TyconRef             -> bool
+
 val valLinkageAEquiv          :            TcGlobals -> TypeEquivEnv -> Val   -> Val -> bool
+
 val anonInfoEquiv             : AnonRecdTypeInfo -> AnonRecdTypeInfo -> bool
 
 //-------------------------------------------------------------------------
@@ -650,11 +864,17 @@ val getErasedTypes            : TcGlobals -> TType -> TType list
 //------------------------------------------------------------------------- 
 
 val MeasurePower : Measure -> int -> Measure
+
 val ListMeasureVarOccsWithNonZeroExponents : Measure -> (Typar * Rational) list
+
 val ListMeasureConOccsWithNonZeroExponents : TcGlobals -> bool -> Measure -> (TyconRef * Rational) list
+
 val ProdMeasures : Measure list -> Measure
+
 val MeasureVarExponent : Typar -> Measure -> Rational
+
 val MeasureExprConExponent : TcGlobals -> bool -> TyconRef -> Measure -> Rational
+
 val normalizeMeasure : TcGlobals -> Measure -> Measure
 
 
@@ -663,19 +883,26 @@ val normalizeMeasure : TcGlobals -> Measure -> Measure
 //------------------------------------------------------------------------- 
 
 val GetTypeOfMemberInFSharpForm : TcGlobals -> ValRef -> Typars * CurriedArgInfos * TType * ArgReprInfo
+
 val GetTypeOfMemberInMemberForm : TcGlobals -> ValRef -> Typars * CurriedArgInfos * TType option * ArgReprInfo
+
 val GetTypeOfIntrinsicMemberInCompiledForm : TcGlobals -> ValRef -> Typars * CurriedArgInfos * TType option * ArgReprInfo
+
 val GetMemberTypeInMemberForm : TcGlobals -> MemberFlags -> ValReprInfo -> TType -> range -> Typars * CurriedArgInfos * TType option * ArgReprInfo
 
 /// Returns (parentTypars,memberParentTypars,memberMethodTypars,memberToParentInst,tinst)
 val PartitionValTyparsForApparentEnclosingType : TcGlobals -> Val -> (Typars * Typars * Typars * TyparInst * TType list) option
+
 /// Returns (parentTypars,memberParentTypars,memberMethodTypars,memberToParentInst,tinst)
 val PartitionValTypars : TcGlobals -> Val -> (Typars * Typars * Typars * TyparInst * TType list) option
+
 /// Returns (parentTypars,memberParentTypars,memberMethodTypars,memberToParentInst,tinst)
 val PartitionValRefTypars : TcGlobals -> ValRef -> (Typars * Typars * Typars * TyparInst * TType list) option
 
 val ReturnTypeOfPropertyVal : TcGlobals -> Val -> TType
+
 val ArgInfosOfPropertyVal : TcGlobals -> Val -> UncurriedArgInfos 
+
 val ArgInfosOfMember: TcGlobals -> ValRef -> CurriedArgInfos 
 
 val GetMemberCallInfo : TcGlobals -> ValRef * ValUseFlag -> int * bool * bool * bool * bool * bool * bool * bool
@@ -686,68 +913,95 @@ val GetMemberCallInfo : TcGlobals -> ValRef * ValUseFlag -> int * bool * bool *
  
 type TyparConstraintsWithTypars = (Typar * TyparConstraint) list
 
-
 module PrettyTypes =
+
     val NeedsPrettyTyparName : Typar -> bool
+
     val NewPrettyTypars : TyparInst -> Typars -> string list -> Typars * TyparInst
+
     val PrettyTyparNames : (Typar -> bool) -> string list -> Typars -> string list
+
     val PrettifyType : TcGlobals -> TType -> TType * TyparConstraintsWithTypars
+
     val PrettifyInstAndTyparsAndType : TcGlobals -> TyparInst * Typars * TType -> (TyparInst * Typars * TType) * TyparConstraintsWithTypars
+
     val PrettifyTypePair : TcGlobals -> TType * TType -> (TType * TType) * TyparConstraintsWithTypars
+
     val PrettifyTypes : TcGlobals -> TTypes -> TTypes * TyparConstraintsWithTypars
+
     val PrettifyInst : TcGlobals -> TyparInst -> TyparInst * TyparConstraintsWithTypars
+
     val PrettifyInstAndType : TcGlobals -> TyparInst * TType -> (TyparInst * TType) * TyparConstraintsWithTypars
+
     val PrettifyInstAndTypes : TcGlobals -> TyparInst * TTypes -> (TyparInst * TTypes) * TyparConstraintsWithTypars
+
     val PrettifyInstAndSig : TcGlobals -> TyparInst * TTypes * TType -> (TyparInst * TTypes * TType) * TyparConstraintsWithTypars
+
     val PrettifyCurriedTypes : TcGlobals -> TType list list -> TType list list * TyparConstraintsWithTypars
+
     val PrettifyCurriedSigTypes : TcGlobals -> TType list list * TType -> (TType list list * TType) * TyparConstraintsWithTypars
+
     val PrettifyInstAndUncurriedSig : TcGlobals -> TyparInst * UncurriedArgInfos * TType -> (TyparInst * UncurriedArgInfos * TType) * TyparConstraintsWithTypars
+
     val PrettifyInstAndCurriedSig : TcGlobals -> TyparInst * TTypes * CurriedArgInfos * TType -> (TyparInst * TTypes * CurriedArgInfos * TType) * TyparConstraintsWithTypars
 
 [<NoEquality; NoComparison>]
 type DisplayEnv = 
-    { includeStaticParametersInTypeNames : bool;
-      openTopPathsSorted: Lazy<string list list>; 
-      openTopPathsRaw: string list list; 
-      shortTypeNames: bool;
-      suppressNestedTypes: bool;
-      maxMembers : int option;
-      showObsoleteMembers: bool; 
-      showHiddenMembers: bool; 
-      showTyparBinding: bool;
-      showImperativeTyparAnnotations: bool;
-      suppressInlineKeyword:bool;
-      suppressMutableKeyword:bool;
-      showMemberContainers: bool;
-      shortConstraints:bool;
-      useColonForReturnType:bool;
-      showAttributes: bool;
-      showOverrides:bool;
-      showConstraintTyparAnnotations:bool;
-      abbreviateAdditionalConstraints: bool;
+    { includeStaticParametersInTypeNames : bool
+      openTopPathsSorted: Lazy<string list list> 
+      openTopPathsRaw: string list list
+      shortTypeNames: bool
+      suppressNestedTypes: bool
+      maxMembers : int option
+      showObsoleteMembers: bool 
+      showHiddenMembers: bool
+      showTyparBinding: bool
+      showImperativeTyparAnnotations: bool
+      suppressInlineKeyword:bool
+      suppressMutableKeyword:bool
+      showMemberContainers: bool
+      shortConstraints:bool
+      useColonForReturnType:bool
+      showAttributes: bool
+      showOverrides:bool
+      showConstraintTyparAnnotations:bool
+      abbreviateAdditionalConstraints: bool
       showTyparDefaultConstraints: bool
       g: TcGlobals
       contextAccessibility: Accessibility
       generatedValueLayout:(Val -> layout option) }
+
     member SetOpenPaths: string list list -> DisplayEnv
+
     static member Empty: TcGlobals -> DisplayEnv
 
     member AddAccessibility : Accessibility -> DisplayEnv
+
     member AddOpenPath : string list  -> DisplayEnv
+
     member AddOpenModuleOrNamespace : ModuleOrNamespaceRef   -> DisplayEnv
 
 val tagEntityRefName: xref: EntityRef -> name: string -> StructuredFormat.TaggedText
 
 /// Return the full text for an item as we want it displayed to the user as a fully qualified entity
 val fullDisplayTextOfModRef : ModuleOrNamespaceRef -> string
+
 val fullDisplayTextOfParentOfModRef : ModuleOrNamespaceRef -> ValueOption<string>
+
 val fullDisplayTextOfValRef   : ValRef -> string
+
 val fullDisplayTextOfValRefAsLayout   : ValRef -> StructuredFormat.Layout
+
 val fullDisplayTextOfTyconRef  : TyconRef -> string
+
 val fullDisplayTextOfTyconRefAsLayout  : TyconRef -> StructuredFormat.Layout
+
 val fullDisplayTextOfExnRef  : TyconRef -> string
+
 val fullDisplayTextOfExnRefAsLayout  : TyconRef -> StructuredFormat.Layout
+
 val fullDisplayTextOfUnionCaseRef  : UnionCaseRef -> string
+
 val fullDisplayTextOfRecdFieldRef  : RecdFieldRef -> string
 
 val ticksAndArgCountTextOfTyconRef : TyconRef -> string
@@ -758,22 +1012,23 @@ val qualifiedMangledNameOfTyconRef : TyconRef -> string -> string
 val trimPathByDisplayEnv : DisplayEnv -> string list -> string
 
 val prefixOfStaticReq : TyparStaticReq -> string
+
 val prefixOfRigidTypar : Typar -> string
 
 /// Utilities used in simplifying types for visual presentation
 module SimplifyTypes = 
+
     type TypeSimplificationInfo =
-        { singletons         : Typar Zset;
-          inplaceConstraints :  Zmap<Typar,TType>;
-          postfixConstraints : TyparConstraintsWithTypars; }
+        { singletons         : Typar Zset
+          inplaceConstraints :  Zmap<Typar,TType>
+          postfixConstraints : TyparConstraintsWithTypars }
+
     val typeSimplificationInfo0 : TypeSimplificationInfo
-    val CollectInfo : bool -> TType list -> TyparConstraintsWithTypars -> TypeSimplificationInfo
 
-//-------------------------------------------------------------------------
-// 
-//------------------------------------------------------------------------- 
+    val CollectInfo : bool -> TType list -> TyparConstraintsWithTypars -> TypeSimplificationInfo
 
 val superOfTycon : TcGlobals -> Tycon -> TType
+
 val abstractSlotValsOfTycons : Tycon list -> Val list
 
 //-------------------------------------------------------------------------
@@ -781,11 +1036,15 @@ val abstractSlotValsOfTycons : Tycon list -> Val list
 //------------------------------------------------------------------------- 
 
 val emptyFreeVars : FreeVars
+
 val unionFreeVars : FreeVars -> FreeVars -> FreeVars
 
 val accFreeInTargets      : FreeVarOptions -> DecisionTreeTarget array -> FreeVars -> FreeVars
+
 val accFreeInExprs        : FreeVarOptions -> Exprs -> FreeVars -> FreeVars
+
 val accFreeInSwitchCases : FreeVarOptions -> DecisionTreeCase list -> DecisionTree option -> FreeVars -> FreeVars
+
 val accFreeInDecisionTree        : FreeVarOptions -> DecisionTree -> FreeVars -> FreeVars
 
 /// Get the free variables in a module definition.
@@ -797,277 +1056,382 @@ val freeInExpr  : FreeVarOptions -> Expr  -> FreeVars
 /// Get the free variables in the right hand side of a binding.
 val freeInBindingRhs   : FreeVarOptions -> Binding  -> FreeVars
 
+/// Check if a set of free type variables are all public
 val freeTyvarsAllPublic  : FreeTyvars -> bool
-val freeVarsAllPublic     : FreeVars -> bool
 
-//-------------------------------------------------------------------------
-// Mark/range/position information from expressions
-//------------------------------------------------------------------------- 
+/// Check if a set of free variables are all public
+val freeVarsAllPublic     : FreeVars -> bool
 
+/// Get the mark/range/position information from an expression
 type Expr with 
     member Range : range
 
-//-------------------------------------------------------------------------
-// type-of operations on the expression tree
-//------------------------------------------------------------------------- 
-
+/// Compute the type of an expression from the expression itself
 val tyOfExpr : TcGlobals -> Expr -> TType 
 
-//-------------------------------------------------------------------------
-// Top expressions to implement top types
-//------------------------------------------------------------------------- 
-
+/// A flag to govern whether arity inference should be type-directed or syntax-directed when 
+/// inferring an arity from a lambda expression.
 [<RequireQualifiedAccess>]
-type AllowTypeDirectedDetupling = Yes | No
+type AllowTypeDirectedDetupling = 
+    | Yes 
+    | No
 
+/// Given a (curried) lambda expression, pull off its arguments
 val stripTopLambda : Expr * TType -> Typars * Val list list * Expr * TType
+
+/// Given a lambda expression, extract the ValReprInfo for its arguments and other details
 val InferArityOfExpr : TcGlobals -> AllowTypeDirectedDetupling -> TType -> Attribs list list -> Attribs -> Expr -> ValReprInfo
+
+/// Given a lambda binding, extract the ValReprInfo for its arguments and other details
 val InferArityOfExprBinding : TcGlobals -> AllowTypeDirectedDetupling -> Val -> Expr -> ValReprInfo
 
-//-------------------------------------------------------------------------
-//  Copy expressions and types
-//------------------------------------------------------------------------- 
-                   
+/// Mutate a value to indicate it should be considered a local rather than a module-bound definition
 // REVIEW: this mutation should not be needed 
 val setValHasNoArity : Val -> Val
 
+/// Indicate what should happen to value definitions when copying expressions
 type ValCopyFlag = 
     | CloneAll
     | CloneAllAndMarkExprValsAsCompilerGenerated
-    // OnlyCloneExprVals is a nasty setting to reuse the cloning logic in a mode where all 
-    // Tycon and "module/member" Val objects keep their identity, but the Val objects for all Expr bindings
-    // are cloned. This is used to 'fixup' the TAST created by tlr.fs 
-    //
-    // This is a fragile mode of use. It's not really clear why TLR needs to create a "bad" expression tree that
-    // reuses Val objects as multiple value bindings, and its been the cause of several subtle bugs.
+
+    /// OnlyCloneExprVals is a nasty setting to reuse the cloning logic in a mode where all 
+    /// Tycon and "module/member" Val objects keep their identity, but the Val objects for all Expr bindings
+    /// are cloned. This is used to 'fixup' the TAST created by tlr.fs 
+    ///
+    /// This is a fragile mode of use. It's not really clear why TLR needs to create a "bad" expression tree that
+    /// reuses Val objects as multiple value bindings, and its been the cause of several subtle bugs.
     | OnlyCloneExprVals
 
+/// Remap a reference to a type definition using the given remapping substitution
 val remapTyconRef : TyconRefRemap -> TyconRef -> TyconRef
+
+/// Remap a reference to a union case using the given remapping substitution
 val remapUnionCaseRef : TyconRefRemap -> UnionCaseRef -> UnionCaseRef
+
+/// Remap a reference to a record field using the given remapping substitution
 val remapRecdFieldRef : TyconRefRemap -> RecdFieldRef -> RecdFieldRef
+
+/// Remap a reference to a value using the given remapping substitution
 val remapValRef : Remap -> ValRef -> ValRef
+
+/// Remap an expression using the given remapping substitution
 val remapExpr : TcGlobals -> ValCopyFlag -> Remap -> Expr -> Expr
+
+/// Remap an attribute using the given remapping substitution
 val remapAttrib : TcGlobals -> Remap -> Attrib -> Attrib
+
+/// Remap a (possible generic) type using the given remapping substitution
 val remapPossibleForallTy : TcGlobals -> Remap -> TType -> TType
+
+/// Copy an entire module or namespace type using the given copying flags
 val copyModuleOrNamespaceType : TcGlobals -> ValCopyFlag -> ModuleOrNamespaceType -> ModuleOrNamespaceType
+
+/// Copy an entire expression using the given copying flags
 val copyExpr : TcGlobals -> ValCopyFlag -> Expr -> Expr
+
+/// Copy an entire implementation file using the given copying flags
 val copyImplFile : TcGlobals -> ValCopyFlag -> TypedImplFile -> TypedImplFile
+
+/// Copy a method slot signature, including new generic type parameters if the slot signature represents a generic method
 val copySlotSig : SlotSig -> SlotSig
+
+/// Instantiate the generic type parameters in a method slot signature, building a new one
 val instSlotSig : TyparInst -> SlotSig -> SlotSig
-val instExpr : TcGlobals -> TyparInst -> Expr -> Expr
 
-//-------------------------------------------------------------------------
-// Build the remapping that corresponds to a module meeting its signature
-// and also report the set of tycons, tycon representations and values hidden in the process.
-//------------------------------------------------------------------------- 
+/// Instantiate the generic type parameters in an expression, building a new one
+val instExpr : TcGlobals -> TyparInst -> Expr -> Expr
 
+/// The remapping that corresponds to a module meeting its signature
+/// and also report the set of tycons, tycon representations and values hidden in the process.
 type SignatureRepackageInfo = 
-    { mrpiVals: (ValRef * ValRef) list;
-      mrpiEntities: (TyconRef * TyconRef) list  }
+    { /// The list of corresponding values
+      RepackagedVals: (ValRef * ValRef) list
+
+      /// The list of corresponding modules, namespacea and type definitions
+      RepackagedEntities: (TyconRef * TyconRef) list  }
 
+    /// The empty table
     static member Empty : SignatureRepackageInfo
       
+/// A set of tables summarizing the items hidden by a signature
 type SignatureHidingInfo = 
-    { mhiTycons  : Zset<Tycon>; 
-      mhiTyconReprs : Zset<Tycon>;  
-      mhiVals       : Zset<Val>; 
-      mhiRecdFields : Zset<RecdFieldRef>;
-      mhiUnionCases : Zset<UnionCaseRef> }
+    { HiddenTycons: Zset<Tycon>
+      HiddenTyconReprs: Zset<Tycon>  
+      HiddenVals: Zset<Val>
+      HiddenRecdFields: Zset<RecdFieldRef>
+      HiddenUnionCases: Zset<UnionCaseRef> }
+
+    /// The empty table representing no hiding
     static member Empty : SignatureHidingInfo
 
-val ComputeRemappingFromInferredSignatureToExplicitSignature : TcGlobals -> ModuleOrNamespaceType -> ModuleOrNamespaceType -> SignatureRepackageInfo * SignatureHidingInfo
+/// Compute the remapping information implied by a signature being inferred for a particular implementation
 val ComputeRemappingFromImplementationToSignature : TcGlobals -> ModuleOrNamespaceExpr -> ModuleOrNamespaceType -> SignatureRepackageInfo * SignatureHidingInfo
+
+/// Compute the remapping information implied by an explicit signature being given for an inferred signature
+val ComputeRemappingFromInferredSignatureToExplicitSignature : TcGlobals -> ModuleOrNamespaceType -> ModuleOrNamespaceType -> SignatureRepackageInfo * SignatureHidingInfo
+
+/// Compute the hiding information that corresponds to the hiding applied at an assembly boundary
 val ComputeHidingInfoAtAssemblyBoundary : ModuleOrNamespaceType -> SignatureHidingInfo -> SignatureHidingInfo
+
 val mkRepackageRemapping : SignatureRepackageInfo -> Remap 
 
+/// Wrap one module or namespace implementation in a 'namespace N' outer wrapper
 val wrapModuleOrNamespaceExprInNamespace : Ident -> CompilationPath -> ModuleOrNamespaceExpr -> ModuleOrNamespaceExpr
+
+/// Wrap one module or namespace definition in a 'namespace N' outer wrapper
 val wrapModuleOrNamespaceTypeInNamespace : Ident -> CompilationPath -> ModuleOrNamespaceType -> ModuleOrNamespaceType * ModuleOrNamespace  
+
+/// Wrap one module or namespace definition in a 'module M = ..' outer wrapper
 val wrapModuleOrNamespaceType : Ident -> CompilationPath -> ModuleOrNamespaceType -> ModuleOrNamespace
 
+/// Given an implementation, fetch its recorded signature
 val SigTypeOfImplFile : TypedImplFile -> ModuleOrNamespaceType
 
-//-------------------------------------------------------------------------
-// Given a list of top-most signatures that together constrain the public compilation units
-// of an assembly, compute a remapping that converts local references to non-local references.
-// This remapping must be applied to all pickled expressions and types 
-// exported from the assembly.
-//------------------------------------------------------------------------- 
-
-
+/// Given a namespace, module or type definition, try to produce a reference to that entity.
 val tryRescopeEntity : CcuThunk -> Entity -> ValueOption<EntityRef>
+
+/// Given a value definition, try to produce a reference to that value. Fails for local values.
 val tryRescopeVal    : CcuThunk -> Remap -> Val -> ValueOption<ValRef>
 
+/// Make the substitution (remapping) table for viewing a module or namespace 'from the outside'
+///
+/// Given the top-most signatures constrains the public compilation units
+/// of an assembly, compute a remapping that converts local references to non-local references.
+/// This remapping must be applied to all pickled expressions and types 
+/// exported from the assembly.
 val MakeExportRemapping : CcuThunk -> ModuleOrNamespace -> Remap
+
+/// Make a remapping table for viewing a module or namespace 'from the outside'
 val ApplyExportRemappingToEntity :  TcGlobals -> Remap -> ModuleOrNamespace -> ModuleOrNamespace 
 
-/// Query SignatureRepackageInfo
+/// Determine if a type definition is hidden by a signature
 val IsHiddenTycon     : (Remap * SignatureHidingInfo) list -> Tycon -> bool
+
+/// Determine if the representation of a type definition is hidden by a signature
 val IsHiddenTyconRepr : (Remap * SignatureHidingInfo) list -> Tycon -> bool
+
+/// Determine if a member, function or value is hidden by a signature
 val IsHiddenVal       : (Remap * SignatureHidingInfo) list -> Val -> bool
-val IsHiddenRecdField : (Remap * SignatureHidingInfo) list -> RecdFieldRef -> bool
 
-//-------------------------------------------------------------------------
-//  Adjust marks in expressions
-//------------------------------------------------------------------------- 
+/// Determine if a record field is hidden by a signature
+val IsHiddenRecdField : (Remap * SignatureHidingInfo) list -> RecdFieldRef -> bool
 
+/// Adjust marks in expressions, replacing all marks by thegiven mark.
+/// Used when inlining.
 val remarkExpr : range -> Expr -> Expr
-
-//-------------------------------------------------------------------------
-// Make applications
-//------------------------------------------------------------------------- 
  
+/// Build the application of a (possibly generic, possibly curried) function value to a set of type and expression arguments
 val primMkApp : (Expr * TType) -> TypeInst -> Exprs -> range -> Expr
+
+/// Build the application of a (possibly generic, possibly curried) function value to a set of type and expression arguments.
+/// Reduce the application via let-bindings if the function value is a lambda expression.
 val mkApps : TcGlobals -> (Expr * TType) * TType list list * Exprs * range -> Expr
+
+/// Build the application of a generic construct to a set of type arguments.
+/// Reduce the application via substitution if the function value is a typed lambda expression.
 val mkTyAppExpr : range -> Expr * TType -> TType list -> Expr
 
+/// Build an expression to mutate a local
 ///   localv <- e      
 val mkValSet   : range -> ValRef -> Expr -> Expr
+
+/// Build an expression to mutate the contents of a local pointer
 ///  *localv_ptr = e   
 val mkAddrSet  : range -> ValRef -> Expr -> Expr
+
+/// Build an expression to dereference a local pointer
 /// *localv_ptr        
 val mkAddrGet  : range -> ValRef -> Expr
+
+/// Build an expression to take the address of a local 
 /// &localv           
 val mkValAddr  : range -> readonly: bool -> ValRef -> Expr
 
-//-------------------------------------------------------------------------
-// Note these take the address of the record expression if it is a struct, and
-// apply a type instantiation if it is a first-class polymorphic record field.
-//------------------------------------------------------------------------- 
-
+/// Build an exression representing the read of an instance class or record field.
+/// First take the address of the record expression if it is a struct.
 val mkRecdFieldGet : TcGlobals -> Expr * RecdFieldRef * TypeInst * range -> Expr
 
-//-------------------------------------------------------------------------
-//  Get the targets used in a decision graph (for reporting warnings)
-//------------------------------------------------------------------------- 
-
+///  Accumulate the targets actually used in a decision graph (for reporting warnings)
 val accTargetsOfDecisionTree : DecisionTree -> int list -> int list
 
-//-------------------------------------------------------------------------
-//  Optimizations on decision graphs
-//------------------------------------------------------------------------- 
-
+/// Make a 'match' expression applying some peep-hole optimizations along the way, e.g to 
+/// pre-decide the branch taken at compile-time.
 val mkAndSimplifyMatch : SequencePointInfoForBinding  -> range -> range -> TType -> DecisionTree -> DecisionTreeTarget list -> Expr
 
+/// Make a 'match' expression without applying any peep-hole optimizations.
 val primMkMatch : SequencePointInfoForBinding * range * DecisionTree * DecisionTreeTarget array * range * TType -> Expr
 
-//-------------------------------------------------------------------------
-//  Work out what things on the r.h.s. of a let rec need to be fixed up
-//------------------------------------------------------------------------- 
-
+///  Work out what things on the right-han-side of a 'let rec' recursive binding need to be fixed up
 val IterateRecursiveFixups : 
    TcGlobals -> Val option  -> 
    (Val option -> Expr -> (Expr -> Expr) -> Expr -> unit) -> 
    Expr * (Expr -> Expr) -> Expr -> unit
 
-//-------------------------------------------------------------------------
-// From lambdas taking multiple variables to lambdas taking a single variable
-// of tuple type. 
-//------------------------------------------------------------------------- 
-
+/// Given a lambda expression taking multiple variables, build a corresponding lambda taking a tuple
 val MultiLambdaToTupledLambda : TcGlobals -> Val list -> Expr -> Val * Expr
-val AdjustArityOfLambdaBody : TcGlobals -> int -> Val list -> Expr -> Val list * Expr
 
-//-------------------------------------------------------------------------
-// Make applications, doing beta reduction by introducing let-bindings
-//------------------------------------------------------------------------- 
+/// Given a lambda expression, adjust it to have be one or two lambda expressions (fun a -> (fun b -> ...)) 
+/// where the first has the given arity.
+val AdjustArityOfLambdaBody : TcGlobals -> int -> Val list -> Expr -> Val list * Expr
 
+/// Make an application expression, doing beta reduction by introducing let-bindings
 val MakeApplicationAndBetaReduce : TcGlobals -> Expr * TType * TypeInst list * Exprs * range -> Expr
 
+/// COmbine two static-resolution requirements on a type parameter
 val JoinTyparStaticReq : TyparStaticReq -> TyparStaticReq -> TyparStaticReq
 
-//-------------------------------------------------------------------------
-// More layout - this is for debugging
-//------------------------------------------------------------------------- 
+/// Layout for internal compiler debugging purposes
 module DebugPrint =
 
+    /// A global flag indicating whether debug output should include ranges
     val layoutRanges : bool ref
+
+    /// Convert a type to a string for debugging purposes
     val showType : TType -> string
+
+    /// Convert an expression to a string for debugging purposes
     val showExpr : Expr -> string
 
+    /// Debug layout for a reference to a value
     val valRefL : ValRef -> layout
+
+    /// Debug layout for a reference to a union case
     val unionCaseRefL : UnionCaseRef -> layout
-    val vspecAtBindL : Val -> layout
+
+    /// Debug layout for an value definition at its binding site
+    val valAtBindL : Val -> layout
+
+    /// Debug layout for an integer
     val intL : int -> layout
+
+    /// Debug layout for a value definition
     val valL : Val -> layout
+
+    /// Debug layout for a type parameter definition
     val typarDeclL : Typar -> layout
+
+    /// Debug layout for a trait constraint
     val traitL : TraitConstraintInfo -> layout
+
+    /// Debug layout for a type parameter
     val typarL : Typar -> layout
+
+    /// Debug layout for a set of type parameters
     val typarsL : Typars -> layout
+
+    /// Debug layout for a type
     val typeL : TType -> layout
+
+    /// Debug layout for a method slot signature
     val slotSigL : SlotSig -> layout
+
+    /// Debug layout for the type signature of a module or namespace definition
     val entityTypeL : ModuleOrNamespaceType -> layout
+
+    /// Debug layout for a module or namespace definition
     val entityL : ModuleOrNamespace -> layout
+
+    /// Debug layout for the type of a value
     val typeOfValL : Val -> layout
+
+    /// Debug layout for a binding of an expression to a value
     val bindingL : Binding -> layout
+
+    /// Debug layout for an expression
     val exprL : Expr -> layout
+
+    /// Debug layout for a type definition
     val tyconL : Tycon -> layout
+
+    /// Debug layout for a decision tree
     val decisionTreeL : DecisionTree -> layout
+
+    /// Debug layout for an implementation file
     val implFileL : TypedImplFile -> layout
+
+    /// Debug layout for a list of implementation files
     val implFilesL : TypedImplFile list -> layout
-    val recdFieldRefL : RecdFieldRef -> layout
 
-//-------------------------------------------------------------------------
-// Fold on expressions
-//------------------------------------------------------------------------- 
+    /// Debug layout for class and record fields
+    val recdFieldRefL : RecdFieldRef -> layout
 
+/// A set of function parameters (visitor) for folding over expressions
 type ExprFolder<'State> =
-    { exprIntercept            : ('State -> Expr -> 'State) -> 'State -> Expr -> 'State option;
-      valBindingSiteIntercept  : 'State -> bool * Val -> 'State;
-      nonRecBindingsIntercept  : 'State -> Binding -> 'State;         
-      recBindingsIntercept     : 'State -> Bindings -> 'State;         
-      dtreeIntercept           : 'State -> DecisionTree -> 'State;
-      targetIntercept          : ('State -> Expr -> 'State) -> 'State -> DecisionTreeTarget -> 'State option;
-      tmethodIntercept         : ('State -> Expr -> 'State) -> 'State -> ObjExprMethod -> 'State option;}
+    { exprIntercept            : ('State -> Expr -> 'State) -> 'State -> Expr -> 'State option
+      valBindingSiteIntercept  : 'State -> bool * Val -> 'State
+      nonRecBindingsIntercept  : 'State -> Binding -> 'State         
+      recBindingsIntercept     : 'State -> Bindings -> 'State         
+      dtreeIntercept           : 'State -> DecisionTree -> 'State
+      targetIntercept          : ('State -> Expr -> 'State) -> 'State -> DecisionTreeTarget -> 'State option
+      tmethodIntercept         : ('State -> Expr -> 'State) -> 'State -> ObjExprMethod -> 'State option}
+
+/// The empty set of actions for folding over expressions
 val ExprFolder0 : ExprFolder<'State>
+
+/// Fold over all the expressions in an implementation file
 val FoldImplFile: ExprFolder<'State> -> ('State -> TypedImplFile -> 'State) 
+
+/// Fold over all the expressions in an expression
 val FoldExpr : ExprFolder<'State> -> ('State -> Expr -> 'State) 
 
 #if DEBUG
+/// Extract some statistics from an expression
 val ExprStats : Expr -> string
 #endif
 
-//-------------------------------------------------------------------------
-// Make some common types
-//------------------------------------------------------------------------- 
-
+/// Build a nativeptr type
 val mkNativePtrTy  : TcGlobals -> TType -> TType
+
+/// Build a 'voidptr' type
 val mkVoidPtrTy  : TcGlobals -> TType
+
+/// Build a single-dimensional array type
 val mkArrayType      : TcGlobals -> TType -> TType
+
+/// Determine is a type is an option type
 val isOptionTy     : TcGlobals -> TType -> bool
+
+/// Take apart an option type
 val destOptionTy   : TcGlobals -> TType -> TType
+
+/// Try to take apart an option type
 val tryDestOptionTy : TcGlobals -> TType -> ValueOption<TType>
 
+/// Determine if a type is a System.Linq.Expression type
 val isLinqExpressionTy     : TcGlobals -> TType -> bool
-val destLinqExpressionTy   : TcGlobals -> TType -> TType
-val tryDestLinqExpressionTy : TcGlobals -> TType -> TType option
 
-(*
-val isQuoteExprTy     : TcGlobals -> TType -> bool
-val destQuoteExprTy   : TcGlobals -> TType -> TType
-val tryDestQuoteExprTy : TcGlobals -> TType -> TType option
-*)
+/// Take apart a System.Linq.Expression type
+val destLinqExpressionTy   : TcGlobals -> TType -> TType
 
-//-------------------------------------------------------------------------
-// Primitives associated with compiling the IEvent idiom to .NET events
-//------------------------------------------------------------------------- 
+/// Try to take apart a System.Linq.Expression type
+val tryDestLinqExpressionTy : TcGlobals -> TType -> TType option
 
+/// Determine if a type is an IDelegateEvent type
 val isIDelegateEventType   : TcGlobals -> TType -> bool
+
+/// Take apart an IDelegateEvent type
 val destIDelegateEventType : TcGlobals -> TType -> TType 
+
+/// Build an IEvent type
 val mkIEventType   : TcGlobals -> TType -> TType -> TType
+
+/// Build an IObservable type
 val mkIObservableType   : TcGlobals -> TType -> TType
-val mkIObserverType   : TcGlobals -> TType -> TType
 
-//-------------------------------------------------------------------------
-// Primitives associated with printf format string parsing
-//------------------------------------------------------------------------- 
+/// Build an IObserver type
+val mkIObserverType   : TcGlobals -> TType -> TType
 
+/// Build an Lazy type
 val mkLazyTy : TcGlobals -> TType -> TType
+
+/// Build an PrintFormat type
 val mkPrintfFormatTy : TcGlobals -> TType -> TType -> TType -> TType -> TType -> TType
 
 //-------------------------------------------------------------------------
 // Classify types
 //------------------------------------------------------------------------- 
 
+/// Represents metadata extracted from a nominal type
 type TypeDefMetadata = 
      | ILTypeMetadata of TILObjectReprData
      | FSharpOrArrayOrByrefOrTupleOrExnTypeMetadata 
@@ -1075,43 +1439,94 @@ type TypeDefMetadata =
      | ProvidedTypeMetadata of  TProvidedTypeInfo
 #endif
 
+/// Extract metadata from a type definition
 val metadataOfTycon : Tycon -> TypeDefMetadata
+
+/// Extract metadata from a type
 val metadataOfTy : TcGlobals -> TType -> TypeDefMetadata
 
-val isStringTy       : TcGlobals -> TType -> bool
-val isListTy         : TcGlobals -> TType -> bool
-val isILAppTy      : TcGlobals -> TType -> bool
-val isArrayTy        : TcGlobals -> TType -> bool
-val isArray1DTy       : TcGlobals -> TType -> bool
-val destArrayTy     : TcGlobals -> TType -> TType
-val destListTy      : TcGlobals -> TType -> TType
+/// Determine if a type is the System.String type
+val isStringTy : TcGlobals -> TType -> bool
+
+/// Determine if a type is an F# list type
+val isListTy : TcGlobals -> TType -> bool
+
+/// Determine if a type is a nominal .NET type
+val isILAppTy : TcGlobals -> TType -> bool
+
+/// Determine if a type is any kind of array type
+val isArrayTy : TcGlobals -> TType -> bool
+
+/// Determine if a type is a single-dimensional array type
+val isArray1DTy : TcGlobals -> TType -> bool
+
+/// Get the element type of an array type
+val destArrayTy : TcGlobals -> TType -> TType
+
+/// Get the element type of an F# list type
+val destListTy : TcGlobals -> TType -> TType
 
-val mkArrayTy         : TcGlobals -> int -> TType -> range -> TType
-val isArrayTyconRef      : TcGlobals -> TyconRef -> bool
+/// Build an array type of the given rank
+val mkArrayTy : TcGlobals -> int -> TType -> range -> TType
+
+/// Check if a type definition is one of the artifical type definitions used for array types of different ranks 
+val isArrayTyconRef : TcGlobals -> TyconRef -> bool
+
+/// Determine the rank of one of the artifical type definitions used for array types
 val rankOfArrayTyconRef : TcGlobals -> TyconRef -> int
 
-val isUnitTy          : TcGlobals -> TType -> bool
-val isObjTy           : TcGlobals -> TType -> bool
-val isVoidTy          : TcGlobals -> TType -> bool
+/// Determine if a type is the F# unit type
+val isUnitTy : TcGlobals -> TType -> bool
+
+/// Determine if a type is the System.Object type
+val isObjTy : TcGlobals -> TType -> bool
+
+/// Determine if a type is the System.Void type
+val isVoidTy : TcGlobals -> TType -> bool
 
 /// Get the element type of an array type
-val destArrayTy    : TcGlobals -> TType -> TType
+val destArrayTy : TcGlobals -> TType -> TType
+
 /// Get the rank of an array type
 val rankOfArrayTy : TcGlobals -> TType -> int
 
-val isInterfaceTyconRef                 : TyconRef -> bool
+/// Determine if a reference to a type definition is an interface type
+val isInterfaceTyconRef : TyconRef -> bool
+
+/// Determine if a type is a delegate type
+val isDelegateTy : TcGlobals -> TType -> bool
+
+/// Determine if a type is an interface type
+val isInterfaceTy : TcGlobals -> TType -> bool
 
-val isDelegateTy                 : TcGlobals -> TType -> bool
-val isInterfaceTy                : TcGlobals -> TType -> bool
-val isRefTy                      : TcGlobals -> TType -> bool
-val isSealedTy                   : TcGlobals -> TType -> bool
-val isComInteropTy               : TcGlobals -> TType -> bool
-val underlyingTypeOfEnumTy       : TcGlobals -> TType -> TType
-val normalizeEnumTy              : TcGlobals -> TType -> TType
+/// Determine if a type is a FSharpRef type
+val isRefTy : TcGlobals -> TType -> bool
+
+/// Determine if a type is a sealed type
+val isSealedTy : TcGlobals -> TType -> bool
+
+/// Determine if a type is a ComInterop type
+val isComInteropTy : TcGlobals -> TType -> bool
+
+/// Determine the underlying type of an enum type (normally int32)
+val underlyingTypeOfEnumTy : TcGlobals -> TType -> TType
+
+/// If the input type is an enum type, then convert to its underlying type, otherwise return the input type
+val normalizeEnumTy : TcGlobals -> TType -> TType
+
+/// Determine if a type is a struct type
 val isStructTy                   : TcGlobals -> TType -> bool
+
+/// Determine if a type is an unmanaged type
 val isUnmanagedTy                : TcGlobals -> TType -> bool
+
+/// Determine if a type is a class type
 val isClassTy                    : TcGlobals -> TType -> bool
+
+/// Determine if a type is an enum type
 val isEnumTy                     : TcGlobals -> TType -> bool
+
+/// Determine if a type is a struct, record or union type
 val isStructRecordOrUnionTyconTy : TcGlobals -> TType -> bool
 
 /// For "type Class as self", 'self' is fixed up after initialization. To support this,
@@ -1119,9 +1534,16 @@ val isStructRecordOrUnionTyconTy : TcGlobals -> TType -> bool
 /// returns the underlying type.
 val StripSelfRefCell : TcGlobals * ValBaseOrThisInfo * TType -> TType
 
+/// An active pattern to determine if a type is a nominal type, possibly instantiated
 val (|AppTy|_|)   : TcGlobals -> TType -> (TyconRef * TType list) option
+
+/// An active pattern to match System.Nullable types
 val (|NullableTy|_|)   : TcGlobals -> TType -> TType option
+
+/// An active pattern to transform System.Nullable types to their input, otherwise leave the input unchanged
 val (|StripNullableTy|)   : TcGlobals -> TType -> TType 
+
+/// Matches any byref type, yielding the target type
 val (|ByrefTy|_|)   : TcGlobals -> TType -> TType option
 
 //-------------------------------------------------------------------------
@@ -1129,35 +1551,53 @@ val (|ByrefTy|_|)   : TcGlobals -> TType -> TType option
 //------------------------------------------------------------------------- 
 
 val IsUnionTypeWithNullAsTrueValue: TcGlobals -> Tycon -> bool
+
 val TyconHasUseNullAsTrueValueAttribute : TcGlobals -> Tycon -> bool
+
 val CanHaveUseNullAsTrueValueAttribute : TcGlobals -> Tycon -> bool
+
 val MemberIsCompiledAsInstance : TcGlobals -> TyconRef -> bool -> ValMemberInfo -> Attribs -> bool
+
 val ValSpecIsCompiledAsInstance : TcGlobals -> Val -> bool
+
 val ValRefIsCompiledAsInstanceMember : TcGlobals -> ValRef -> bool
+
 val ModuleNameIsMangled : TcGlobals -> Attribs -> bool
 
 val CompileAsEvent : TcGlobals -> Attribs -> bool
 
 val TypeNullIsExtraValue : TcGlobals -> range -> TType -> bool
+
 val TypeNullIsTrueValue : TcGlobals -> TType -> bool
+
 val TypeNullNotLiked : TcGlobals -> range -> TType -> bool
+
 val TypeNullNever : TcGlobals -> TType -> bool
 
 val TypeSatisfiesNullConstraint : TcGlobals -> range -> TType -> bool
+
 val TypeHasDefaultValue : TcGlobals -> range -> TType -> bool
 
 val isAbstractTycon : Tycon -> bool
 
 val isUnionCaseRefDefinitelyMutable : UnionCaseRef -> bool
+
 val isRecdOrUnionOrStructTyconRefDefinitelyMutable : TyconRef -> bool
+
 val isExnDefinitelyMutable : TyconRef -> bool 
+
 val isUnionCaseFieldMutable : TcGlobals -> UnionCaseRef -> int -> bool
+
 val isExnFieldMutable : TyconRef -> int -> bool
+
 val isRecdOrStructTyconRefReadOnly: TcGlobals -> range -> TyconRef -> bool
+
 val isRecdOrStructTyconRefAssumedImmutable: TcGlobals -> TyconRef -> bool
+
 val isRecdOrStructTyReadOnly: TcGlobals -> range -> TType -> bool
 
 val useGenuineField : Tycon -> RecdField -> bool 
+
 val ComputeFieldName : Tycon -> RecdField -> string
 
 //-------------------------------------------------------------------------
@@ -1165,6 +1605,7 @@ val ComputeFieldName : Tycon -> RecdField -> string
 //------------------------------------------------------------------------- 
 
 val slotSigHasVoidReturnTy     : SlotSig -> bool
+
 val actualReturnTyOfSlotSig    : TypeInst -> TypeInst -> SlotSig -> TType option
 
 val returnTyOfMethod : TcGlobals -> ObjExprMethod -> TType option
@@ -1174,25 +1615,37 @@ val returnTyOfMethod : TcGlobals -> ObjExprMethod -> TType option
 //------------------------------------------------------------------------- 
 
 val mkRefCell              : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkRefCellGet          : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkRefCellSet          : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkLazyDelayed         : TcGlobals -> range -> TType -> Expr -> Expr
-val mkLazyForce           : TcGlobals -> range -> TType -> Expr -> Expr
 
+val mkLazyForce           : TcGlobals -> range -> TType -> Expr -> Expr
 
 val mkRefCellContentsRef : TcGlobals -> RecdFieldRef
+
 val isRefCellTy   : TcGlobals -> TType -> bool
+
 val destRefCellTy : TcGlobals -> TType -> TType
+
 val mkRefCellTy   : TcGlobals -> TType -> TType
 
 val mkSeqTy          : TcGlobals -> TType -> TType
+
 val mkIEnumeratorTy  : TcGlobals -> TType -> TType
+
 val mkListTy         : TcGlobals -> TType -> TType
+
 val mkOptionTy       : TcGlobals -> TType -> TType
+
 val mkNoneCase  : TcGlobals -> UnionCaseRef
+
 val mkSomeCase  : TcGlobals -> UnionCaseRef
 
 val mkNil  : TcGlobals -> range -> TType -> Expr
+
 val mkCons : TcGlobals -> TType -> Expr -> Expr -> Expr
 
 //-------------------------------------------------------------------------
@@ -1200,17 +1653,29 @@ val mkCons : TcGlobals -> TType -> Expr -> Expr -> Expr
 //------------------------------------------------------------------------- 
 
 val mkSequential  : SequencePointInfoForSeq -> range -> Expr -> Expr -> Expr
+
 val mkCompGenSequential  : range -> Expr -> Expr -> Expr
+
 val mkSequentials : SequencePointInfoForSeq -> TcGlobals -> range -> Exprs -> Expr   
+
 val mkRecordExpr : TcGlobals -> RecordConstructionInfo * TyconRef * TypeInst * RecdFieldRef list * Exprs * range -> Expr
+
 val mkUnbox : TType -> Expr -> range -> Expr
+
 val mkBox : TType -> Expr -> range -> Expr
+
 val mkIsInst : TType -> Expr -> range -> Expr
+
 val mkNull : range -> TType -> Expr
+
 val mkNullTest : TcGlobals -> range -> Expr -> Expr -> Expr -> Expr
+
 val mkNonNullTest : TcGlobals -> range -> Expr -> Expr
+
 val mkIsInstConditional : TcGlobals -> range -> TType -> Expr -> Val -> Expr -> Expr -> Expr
+
 val mkThrow   : range -> TType -> Expr -> Expr
+
 val mkGetArg0 : range -> TType -> Expr
 
 val mkDefault : range * TType -> Expr
@@ -1218,18 +1683,31 @@ val mkDefault : range * TType -> Expr
 val isThrow : Expr -> bool
 
 val mkString    : TcGlobals -> range -> string -> Expr
+
 val mkBool      : TcGlobals -> range -> bool -> Expr
+
 val mkByte      : TcGlobals -> range -> byte -> Expr
+
 val mkUInt16    : TcGlobals -> range -> uint16 -> Expr
+
 val mkTrue      : TcGlobals -> range -> Expr
+
 val mkFalse     : TcGlobals -> range -> Expr
+
 val mkUnit      : TcGlobals -> range -> Expr
+
 val mkInt32     : TcGlobals -> range -> int32 -> Expr
+
 val mkInt       : TcGlobals -> range -> int -> Expr
+
 val mkZero      : TcGlobals -> range -> Expr
+
 val mkOne       : TcGlobals -> range -> Expr
+
 val mkTwo       : TcGlobals -> range -> Expr
+
 val mkMinusOne : TcGlobals -> range -> Expr
+
 val destInt32 : Expr -> int32 option
 
 //-------------------------------------------------------------------------
@@ -1237,8 +1715,11 @@ val destInt32 : Expr -> int32 option
 //------------------------------------------------------------------------- 
  
 val isQuotedExprTy : TcGlobals -> TType -> bool
+
 val destQuotedExprTy : TcGlobals -> TType -> TType
+
 val mkQuotedExprTy : TcGlobals -> TType -> TType
+
 val mkRawQuotedExprTy : TcGlobals -> TType
 
 //-------------------------------------------------------------------------
@@ -1246,9 +1727,13 @@ val mkRawQuotedExprTy : TcGlobals -> TType
 //------------------------------------------------------------------------- 
 
 val mspec_Type_GetTypeFromHandle : TcGlobals ->  ILMethodSpec
+
 val fspec_Missing_Value : TcGlobals ->  ILFieldSpec
+
 val mkInitializeArrayMethSpec: TcGlobals -> ILMethodSpec 
+
 val mkByteArrayTy : TcGlobals -> TType
+
 val mkInvalidCastExnNewobj: TcGlobals -> ILInstr
 
 
@@ -1259,122 +1744,207 @@ val mkInvalidCastExnNewobj: TcGlobals -> ILInstr
 val mkCallNewFormat              : TcGlobals -> range -> TType -> TType -> TType -> TType -> TType -> Expr -> Expr
 
 val mkCallUnbox       : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallGetGenericComparer : TcGlobals -> range -> Expr
+
 val mkCallGetGenericEREqualityComparer : TcGlobals -> range -> Expr
+
 val mkCallGetGenericPEREqualityComparer : TcGlobals -> range -> Expr
 
 val mkCallUnboxFast  : TcGlobals -> range -> TType -> Expr -> Expr
+
 val canUseUnboxFast  : TcGlobals -> range -> TType -> bool
 
 val mkCallDispose     : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallSeq         : TcGlobals -> range -> TType -> Expr -> Expr
 
 val mkCallTypeTest      : TcGlobals -> range -> TType -> Expr -> Expr
+
 val canUseTypeTestFast : TcGlobals -> TType -> bool
 
 val mkCallTypeOf      : TcGlobals -> range -> TType -> Expr
+
 val mkCallTypeDefOf   : TcGlobals -> range -> TType -> Expr 
 
 val mkCallCreateInstance     : TcGlobals -> range -> TType -> Expr
+
 val mkCallCreateEvent        : TcGlobals -> range -> TType -> TType -> Expr -> Expr -> Expr -> Expr
+
 val mkCallArrayLength        : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallArrayGet           : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallArray2DGet         : TcGlobals -> range -> TType -> Expr -> Expr -> Expr -> Expr 
+
 val mkCallArray3DGet         : TcGlobals -> range -> TType -> Expr -> Expr -> Expr -> Expr -> Expr
+
 val mkCallArray4DGet         : TcGlobals -> range -> TType -> Expr -> Expr -> Expr -> Expr -> Expr -> Expr
+
 val mkCallArraySet           : TcGlobals -> range -> TType -> Expr -> Expr -> Expr -> Expr
+
 val mkCallArray2DSet         : TcGlobals -> range -> TType -> Expr -> Expr -> Expr -> Expr -> Expr
+
 val mkCallArray3DSet         : TcGlobals -> range -> TType -> Expr -> Expr -> Expr -> Expr -> Expr -> Expr
+
 val mkCallArray4DSet         : TcGlobals -> range -> TType -> Expr -> Expr -> Expr -> Expr -> Expr -> Expr -> Expr
 
 val mkCallHash               : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallBox                : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallIsNull             : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallIsNotNull          : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallRaise              : TcGlobals -> range -> TType -> Expr -> Expr
 
 val mkCallGenericComparisonWithComparerOuter : TcGlobals -> range -> TType -> Expr -> Expr -> Expr -> Expr
+
 val mkCallGenericEqualityEROuter             : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallGenericEqualityWithComparerOuter   : TcGlobals -> range -> TType -> Expr -> Expr -> Expr -> Expr
+
 val mkCallGenericHashWithComparerOuter       : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
 
 val mkCallEqualsOperator                     : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallNotEqualsOperator                  : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallLessThanOperator                   : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallLessThanOrEqualsOperator           : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallGreaterThanOperator                : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallGreaterThanOrEqualsOperator        : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
 
 val mkCallAdditionOperator                   : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallSubtractionOperator                : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallMultiplyOperator                   : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallDivisionOperator                   : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallModulusOperator                    : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallBitwiseAndOperator                 : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallBitwiseOrOperator                  : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallBitwiseXorOperator                 : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallShiftLeftOperator                  : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallShiftRightOperator                 : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
 
 val mkCallUnaryNegOperator                   : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallUnaryNotOperator                   : TcGlobals -> range -> TType -> Expr -> Expr
 
 val mkCallAdditionChecked                    : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallSubtractionChecked                 : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallMultiplyChecked                    : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallUnaryNegChecked                    : TcGlobals -> range -> TType -> Expr -> Expr
 
 val mkCallToByteChecked                      : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToSByteChecked                     : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToInt16Checked                     : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToUInt16Checked                    : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToIntChecked                       : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToInt32Checked                     : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToUInt32Checked                    : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToInt64Checked                     : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToUInt64Checked                    : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToIntPtrChecked                    : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToUIntPtrChecked                   : TcGlobals -> range -> TType -> Expr -> Expr
 
 val mkCallToByteOperator                     : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToSByteOperator                    : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToInt16Operator                    : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToUInt16Operator                   : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToIntOperator                      : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToInt32Operator                    : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToUInt32Operator                   : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToInt64Operator                    : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToUInt64Operator                   : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToSingleOperator                   : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToDoubleOperator                   : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToIntPtrOperator                   : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToUIntPtrOperator                  : TcGlobals -> range -> TType -> Expr -> Expr
 
 val mkCallToCharOperator                     : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallToEnumOperator                     : TcGlobals -> range -> TType -> Expr -> Expr
 
 val mkCallDeserializeQuotationFSharp20Plus  : TcGlobals -> range -> Expr -> Expr -> Expr -> Expr -> Expr
+
 val mkCallDeserializeQuotationFSharp40Plus : TcGlobals -> range -> Expr -> Expr -> Expr -> Expr -> Expr -> Expr
+
 val mkCallCastQuotation      : TcGlobals -> range -> TType -> Expr -> Expr 
+
 val mkCallLiftValueWithName          : TcGlobals -> range -> TType -> string -> Expr -> Expr
+
 val mkCallLiftValueWithDefn          : TcGlobals -> range -> TType -> Expr -> Expr
+
 val mkCallSeqCollect         : TcGlobals -> range -> TType  -> TType -> Expr -> Expr -> Expr
+
 val mkCallSeqUsing           : TcGlobals -> range -> TType  -> TType -> Expr -> Expr -> Expr
+
 val mkCallSeqDelay           : TcGlobals -> range -> TType  -> Expr -> Expr
+
 val mkCallSeqAppend          : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallSeqFinally         : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallSeqGenerated       : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
+
 val mkCallSeqOfFunctions    : TcGlobals -> range -> TType  -> TType -> Expr -> Expr -> Expr -> Expr
+
 val mkCallSeqToArray        : TcGlobals -> range -> TType  -> Expr -> Expr 
+
 val mkCallSeqToList         : TcGlobals -> range -> TType  -> Expr -> Expr 
+
 val mkCallSeqMap             : TcGlobals -> range -> TType  -> TType -> Expr -> Expr -> Expr
+
 val mkCallSeqSingleton       : TcGlobals -> range -> TType  -> Expr -> Expr
+
 val mkCallSeqEmpty           : TcGlobals -> range -> TType  -> Expr
+
 val mkILAsmCeq                   : TcGlobals -> range -> Expr -> Expr -> Expr
+
 val mkILAsmClt                   : TcGlobals -> range -> Expr -> Expr -> Expr
 
 val mkCallFailInit           : TcGlobals -> range -> Expr 
+
 val mkCallFailStaticInit    : TcGlobals -> range -> Expr 
+
 val mkCallCheckThis          : TcGlobals -> range -> TType -> Expr -> Expr 
 
 val mkCase : DecisionTreeTest * DecisionTree -> DecisionTreeCase
@@ -1382,13 +1952,17 @@ val mkCase : DecisionTreeTest * DecisionTree -> DecisionTreeCase
 val mkCallQuoteToLinqLambdaExpression : TcGlobals -> range -> TType -> Expr -> Expr
 
 val mkCallGetQuerySourceAsEnumerable : TcGlobals -> range -> TType -> TType -> Expr -> Expr
+
 val mkCallNewQuerySource : TcGlobals -> range -> TType -> TType -> Expr -> Expr
 
 val mkArray : TType * Exprs * range -> Expr
 
 val mkStaticCall_String_Concat2 : TcGlobals -> range -> Expr -> Expr -> Expr
+
 val mkStaticCall_String_Concat3 : TcGlobals -> range -> Expr -> Expr -> Expr -> Expr
+
 val mkStaticCall_String_Concat4 : TcGlobals -> range -> Expr -> Expr -> Expr -> Expr -> Expr
+
 val mkStaticCall_String_Concat_Array : TcGlobals -> range -> Expr -> Expr
 
 //-------------------------------------------------------------------------
@@ -1397,8 +1971,11 @@ val mkStaticCall_String_Concat_Array : TcGlobals -> range -> Expr -> Expr
 //------------------------------------------------------------------------- 
 
 val mkDecr   : TcGlobals -> range -> Expr -> Expr
+
 val mkIncr   : TcGlobals -> range -> Expr -> Expr
+
 val mkLdlen  : TcGlobals -> range -> Expr -> Expr
+
 val mkLdelem : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
 
 //-------------------------------------------------------------------------
@@ -1406,18 +1983,29 @@ val mkLdelem : TcGlobals -> range -> TType -> Expr -> Expr -> Expr
 //------------------------------------------------------------------------- 
 
 val TryDecodeILAttribute   : TcGlobals -> ILTypeRef -> ILAttributes -> (ILAttribElem list * ILAttributeNamedArg list) option
+
 val TryFindILAttribute : BuiltinAttribInfo -> ILAttributes -> bool
+
 val TryFindILAttributeOpt : BuiltinAttribInfo option -> ILAttributes -> bool
 
 val IsMatchingFSharpAttribute      : TcGlobals -> BuiltinAttribInfo -> Attrib -> bool
+
 val IsMatchingFSharpAttributeOpt   : TcGlobals -> BuiltinAttribInfo option -> Attrib -> bool
+
 val HasFSharpAttribute             : TcGlobals -> BuiltinAttribInfo -> Attribs -> bool
+
 val HasFSharpAttributeOpt          : TcGlobals -> BuiltinAttribInfo option -> Attribs -> bool
+
 val TryFindFSharpAttribute         : TcGlobals -> BuiltinAttribInfo -> Attribs -> Attrib option
+
 val TryFindFSharpAttributeOpt      : TcGlobals -> BuiltinAttribInfo option -> Attribs -> Attrib option
+
 val TryFindFSharpBoolAttribute     : TcGlobals -> BuiltinAttribInfo -> Attribs -> bool option
+
 val TryFindFSharpBoolAttributeAssumeFalse : TcGlobals -> BuiltinAttribInfo -> Attribs -> bool option
+
 val TryFindFSharpStringAttribute   : TcGlobals -> BuiltinAttribInfo -> Attribs -> string option
+
 val TryFindFSharpInt32Attribute    : TcGlobals -> BuiltinAttribInfo -> Attribs -> int32 option
 
 /// Try to find a specific attribute on a type definition, where the attribute accepts a string argument.
@@ -1438,19 +2026,29 @@ val TryFindAttributeUsageAttribute : TcGlobals -> range -> TyconRef -> bool opti
 /// returns Some(assemblyName) for success
 val TryDecodeTypeProviderAssemblyAttr : ILGlobals -> ILAttribute -> string option
 #endif
+
 val IsSignatureDataVersionAttr  : ILAttribute -> bool
+
 val TryFindAutoOpenAttr           : IL.ILGlobals -> ILAttribute -> string option 
+
 val TryFindInternalsVisibleToAttr : IL.ILGlobals -> ILAttribute -> string option 
-val IsMatchingSignatureDataVersionAttr : IL.ILGlobals -> ILVersionInfo -> ILAttribute -> bool
 
+val IsMatchingSignatureDataVersionAttr : IL.ILGlobals -> ILVersionInfo -> ILAttribute -> bool
 
 val mkCompilationMappingAttr                         : TcGlobals -> int -> ILAttribute
 val mkCompilationMappingAttrWithSeqNum               : TcGlobals -> int -> int -> ILAttribute
+
+
 val mkCompilationMappingAttrWithVariantNumAndSeqNum  : TcGlobals -> int -> int -> int             -> ILAttribute
+
 val mkCompilationMappingAttrForQuotationResource     : TcGlobals -> string * ILTypeRef list -> ILAttribute
+
 val mkCompilationArgumentCountsAttr                  : TcGlobals -> int list -> ILAttribute
+
 val mkCompilationSourceNameAttr                      : TcGlobals -> string -> ILAttribute
+
 val mkSignatureDataVersionAttr                       : TcGlobals -> ILVersionInfo -> ILAttribute
+
 val mkCompilerGeneratedAttr                          : TcGlobals -> int -> ILAttribute
 
 //-------------------------------------------------------------------------
@@ -1458,16 +2056,23 @@ val mkCompilerGeneratedAttr                          : TcGlobals -> int -> ILAtt
 //------------------------------------------------------------------------- 
 
 val isInByrefTy : TcGlobals -> TType -> bool
+
 val isOutByrefTy : TcGlobals -> TType -> bool
+
 val isByrefTy : TcGlobals -> TType -> bool
 
 val isNativePtrTy : TcGlobals -> TType -> bool
+
 val destByrefTy : TcGlobals -> TType -> TType
+
 val destNativePtrTy : TcGlobals -> TType -> TType
 
 val isByrefTyconRef : TcGlobals -> TyconRef -> bool
+
 val isByrefLikeTyconRef : TcGlobals -> range -> TyconRef -> bool
+
 val isSpanLikeTyconRef : TcGlobals -> range -> TyconRef -> bool
+
 val isByrefLikeTy : TcGlobals -> range -> TType -> bool
 
 /// Check if the type is a byref-like but not a byref.
@@ -1478,33 +2083,37 @@ val isSpanLikeTy : TcGlobals -> range -> TType -> bool
 //------------------------------------------------------------------------- 
 
 val isRefTupleExpr : Expr -> bool
+
 val tryDestRefTupleExpr : Expr -> Exprs
 
 val mkAnyTupledTy : TcGlobals -> TupInfo -> TType list -> TType
+
 val mkAnyTupled : TcGlobals -> range -> TupInfo -> Exprs -> TType list -> Expr 
+
 val mkRefTupled : TcGlobals -> range -> Exprs -> TType list -> Expr 
+
 val mkRefTupledNoTypes : TcGlobals -> range -> Exprs -> Expr 
+
 val mkRefTupledTy : TcGlobals -> TType list -> TType
+
 val mkRefTupledVarsTy : TcGlobals -> Val list -> TType
-val mkRefTupledVars : TcGlobals -> range -> Val list -> Expr 
-val mkMethodTy : TcGlobals -> TType list list -> TType -> TType
 
+val mkRefTupledVars : TcGlobals -> range -> Val list -> Expr 
 
-//-------------------------------------------------------------------------
-// Anonymous records
-//------------------------------------------------------------------------- 
+val mkMethodTy : TcGlobals -> TType list list -> TType -> TType
 
 val mkAnyAnonRecdTy : TcGlobals -> AnonRecdTypeInfo -> TType list -> TType
-val mkAnonRecd : TcGlobals -> range -> AnonRecdTypeInfo -> Exprs -> TType list -> Expr 
 
-//-------------------------------------------------------------------------
-// 
-//------------------------------------------------------------------------- 
+val mkAnonRecd : TcGlobals -> range -> AnonRecdTypeInfo -> Exprs -> TType list -> Expr 
 
 val AdjustValForExpectedArity : TcGlobals -> range -> ValRef -> ValUseFlag -> ValReprInfo -> Expr * TType
+
 val AdjustValToTopVal : Val -> ParentRef -> ValReprInfo -> unit
+
 val LinearizeTopMatch : TcGlobals -> ParentRef -> Expr -> Expr
+
 val AdjustPossibleSubsumptionExpr : TcGlobals -> Expr -> Exprs -> (Expr * Exprs) option
+
 val NormalizeAndAdjustPossibleSubsumptionExprs : TcGlobals -> Expr -> Expr
 
 //-------------------------------------------------------------------------
@@ -1514,28 +2123,35 @@ val NormalizeAndAdjustPossibleSubsumptionExprs : TcGlobals -> Expr -> Expr
 val buildAccessPath : CompilationPath option -> string
 
 val XmlDocArgsEnc : TcGlobals -> Typars * Typars -> TType list -> string
+
 val XmlDocSigOfVal : TcGlobals -> string -> Val -> string
+
 val XmlDocSigOfUnionCase : (string list -> string)
+
 val XmlDocSigOfField : (string list -> string)
+
 val XmlDocSigOfProperty : (string list -> string)
+
 val XmlDocSigOfTycon : (string list -> string)
+
 val XmlDocSigOfSubModul : (string list -> string)
+
 val XmlDocSigOfEntity : EntityRef -> string
 
 //---------------------------------------------------------------------------
 // Resolve static optimizations
 //------------------------------------------------------------------------- 
+
 type StaticOptimizationAnswer = 
     | Yes = 1y
     | No = -1y
     | Unknown = 0y
+
 val DecideStaticOptimizations : TcGlobals -> StaticOptimization list -> StaticOptimizationAnswer
-val mkStaticOptimizationExpr     : TcGlobals -> StaticOptimization list * Expr * Expr * range -> Expr
 
-//---------------------------------------------------------------------------
-// Build for loops
-//------------------------------------------------------------------------- 
+val mkStaticOptimizationExpr     : TcGlobals -> StaticOptimization list * Expr * Expr * range -> Expr
 
+/// Build for loops
 val mkFastForLoop : TcGlobals -> SequencePointInfoForForLoop * range * Val * Expr * bool * Expr * Expr -> Expr
 
 //---------------------------------------------------------------------------
@@ -1546,12 +2162,15 @@ type ActivePatternElemRef with
     member Name : string
 
 val TryGetActivePatternInfo  : ValRef -> PrettyNaming.ActivePatternInfo option
+
 val mkChoiceCaseRef : TcGlobals -> range -> int -> int -> UnionCaseRef
 
 type PrettyNaming.ActivePatternInfo with 
+
     member Names : string list 
 
     member ResultType : TcGlobals -> range -> TType list -> TType
+
     member OverallType : TcGlobals -> range -> TType -> TType list -> TType
 
 val doesActivePatternHaveFreeTypars : TcGlobals -> ValRef -> bool
@@ -1562,61 +2181,84 @@ val doesActivePatternHaveFreeTypars : TcGlobals -> ValRef -> bool
 
 [<NoEquality; NoComparison>]
 type ExprRewritingEnv = 
-    {PreIntercept: ((Expr -> Expr) -> Expr -> Expr option) option;
-     PostTransform: Expr -> Expr option;
-     PreInterceptBinding: ((Expr -> Expr) -> Binding -> Binding option) option;
-     IsUnderQuotations: bool }    
+    { PreIntercept: ((Expr -> Expr) -> Expr -> Expr option) option
+      PostTransform: Expr -> Expr option
+      PreInterceptBinding: ((Expr -> Expr) -> Binding -> Binding option) option
+      IsUnderQuotations: bool }    
 
 val RewriteExpr : ExprRewritingEnv -> Expr -> Expr
+
 val RewriteImplFile : ExprRewritingEnv -> TypedImplFile -> TypedImplFile
 
 val IsGenericValWithGenericContraints: TcGlobals -> Val -> bool
 
 type Entity with 
+
     member HasInterface : TcGlobals -> TType -> bool
+
     member HasOverride : TcGlobals -> string -> TType list -> bool
+
     member HasMember : TcGlobals -> string -> TType list -> bool
 
 type EntityRef with 
+
     member HasInterface : TcGlobals -> TType -> bool
+
     member HasOverride : TcGlobals -> string -> TType list -> bool
+
     member HasMember : TcGlobals -> string -> TType list -> bool
 
 val (|AttribBitwiseOrExpr|_|) : TcGlobals -> Expr -> (Expr * Expr) option
+
 val (|EnumExpr|_|) : TcGlobals -> Expr -> Expr option
+
 val (|TypeOfExpr|_|) : TcGlobals -> Expr -> TType option
+
 val (|TypeDefOfExpr|_|) : TcGlobals -> Expr -> TType option
 
 val EvalLiteralExprOrAttribArg: TcGlobals -> Expr -> Expr
+
 val EvaledAttribExprEquality : TcGlobals -> Expr -> Expr -> bool
+
 val IsSimpleSyntacticConstantExpr: TcGlobals -> Expr -> bool
 
 val (|ConstToILFieldInit|_|): Const -> ILFieldInit option
 
 val (|ExtractAttribNamedArg|_|) : string -> AttribNamedArg list -> AttribExpr option 
+
 val (|AttribInt32Arg|_|) : AttribExpr -> int32 option
+
 val (|AttribInt16Arg|_|) : AttribExpr -> int16 option
+
 val (|AttribBoolArg|_|) : AttribExpr -> bool option
+
 val (|AttribStringArg|_|) : AttribExpr -> string option
+
 val (|Int32Expr|_|) : Expr -> int32 option
 
 
 /// Determines types that are potentially known to satisfy the 'comparable' constraint and returns
 /// a set of residual types that must also satisfy the constraint
 val (|SpecialComparableHeadType|_|) : TcGlobals -> TType -> TType list option
+
 val (|SpecialEquatableHeadType|_|) : TcGlobals -> TType -> TType list option
+
 val (|SpecialNotEquatableHeadType|_|) : TcGlobals -> TType -> unit option
 
 type OptimizeForExpressionOptions = OptimizeIntRangesOnly | OptimizeAllForExpressions
+
 val DetectAndOptimizeForExpression : TcGlobals -> OptimizeForExpressionOptions -> Expr -> Expr
 
 val TryEliminateDesugaredConstants : TcGlobals -> range -> Const -> Expr option
 
 val MemberIsExplicitImpl : TcGlobals -> ValMemberInfo -> bool
+
 val ValIsExplicitImpl : TcGlobals -> Val -> bool
+
 val ValRefIsExplicitImpl : TcGlobals -> ValRef -> bool
 
 val (|LinearMatchExpr|_|) : Expr -> (SequencePointInfoForBinding * range * DecisionTree * DecisionTreeTarget * Expr * SequencePointInfoForTarget * range * TType) option
+
 val rebuildLinearMatchExpr : (SequencePointInfoForBinding * range * DecisionTree * DecisionTreeTarget * Expr * SequencePointInfoForTarget * range * TType) -> Expr
 
 val mkCoerceIfNeeded : TcGlobals -> tgtTy: TType -> srcTy: TType -> Expr -> Expr
diff --git a/src/fsharp/TypeChecker.fs b/src/fsharp/TypeChecker.fs
index 0651a6407e4..0239602c496 100755
--- a/src/fsharp/TypeChecker.fs
+++ b/src/fsharp/TypeChecker.fs
@@ -504,8 +504,8 @@ type cenv =
       /// Used to resolve names
       nameResolver: NameResolver
       
-      /// The set of active conditional defines
-      conditionalDefines: string list
+      /// The set of active conditional defines. The value is None when conditional erasure is disabled in tooling.
+      conditionalDefines: string list option
             
       isInternalTestSpanStackReferring: bool
     } 
@@ -3004,8 +3004,8 @@ let BuildPossiblyConditionalMethodCall cenv env isMutable m isProp minfo valUseF
 
     let conditionalCallDefineOpt = TryFindMethInfoStringAttribute cenv.g m cenv.g.attrib_ConditionalAttribute minfo 
 
-    match conditionalCallDefineOpt with 
-    | Some d when not (List.contains d cenv.conditionalDefines) -> 
+    match conditionalCallDefineOpt, cenv.conditionalDefines with 
+    | Some d, Some defines when not (List.contains d defines) -> 
 
         // Methods marked with 'Conditional' must return 'unit' 
         UnifyTypes cenv env m cenv.g.unit_ty (minfo.GetFSharpReturnTy(cenv.amap, m, minst))
@@ -10060,7 +10060,7 @@ and TcMethodApplication
                                     | CallerLineNumber, _ when typeEquiv cenv.g currCalledArgTy cenv.g.int_ty ->
                                         emptyPreBinder, Expr.Const(Const.Int32(mMethExpr.StartLine), mMethExpr, currCalledArgTy)
                                     | CallerFilePath, _ when typeEquiv cenv.g currCalledArgTy cenv.g.string_ty ->
-                                        emptyPreBinder, Expr.Const(Const.String(System.IO.Path.GetFullPath(mMethExpr.FileName)), mMethExpr, currCalledArgTy)
+                                        emptyPreBinder, Expr.Const(Const.String(FileSystem.GetFullPathShim(mMethExpr.FileName)), mMethExpr, currCalledArgTy)
                                     | CallerMemberName, Some(callerName) when (typeEquiv cenv.g currCalledArgTy cenv.g.string_ty) ->
                                         emptyPreBinder, Expr.Const(Const.String(callerName), mMethExpr, currCalledArgTy)
                                     | _ ->
@@ -10099,7 +10099,7 @@ and TcMethodApplication
                           let lineExpr = Expr.Const(Const.Int32(mMethExpr.StartLine), mMethExpr, calledNonOptTy)
                           emptyPreBinder, mkUnionCaseExpr(mkSomeCase cenv.g, [calledNonOptTy], [lineExpr], mMethExpr)
                       | CallerFilePath, _ when typeEquiv cenv.g calledNonOptTy cenv.g.string_ty ->
-                          let filePathExpr = Expr.Const(Const.String(System.IO.Path.GetFullPath(mMethExpr.FileName)), mMethExpr, calledNonOptTy)
+                          let filePathExpr = Expr.Const(Const.String(FileSystem.GetFullPathShim(mMethExpr.FileName)), mMethExpr, calledNonOptTy)
                           emptyPreBinder, mkUnionCaseExpr(mkSomeCase cenv.g, [calledNonOptTy], [filePathExpr], mMethExpr)
                       | CallerMemberName, Some(callerName) when typeEquiv cenv.g calledNonOptTy cenv.g.string_ty ->
                           let memberNameExpr = Expr.Const(Const.String(callerName), mMethExpr, calledNonOptTy)
@@ -10828,11 +10828,10 @@ and TcAttribute canFail cenv (env: TcEnv) attrTgt (synAttr: SynAttribute)  =
 
     let conditionalCallDefineOpt = TryFindTyconRefStringAttribute cenv.g mAttr cenv.g.attrib_ConditionalAttribute tcref 
 
-    match conditionalCallDefineOpt with 
-    | Some d when not (List.contains d cenv.conditionalDefines) -> 
+    match conditionalCallDefineOpt, cenv.conditionalDefines with 
+    | Some d, Some defines when not (List.contains d defines) -> 
         [], false
     | _ ->
-
          // REVIEW: take notice of inherited? 
         let validOn, _inherited = 
             let validOnDefault = 0x7fff
@@ -16713,7 +16712,7 @@ let rec TcSignatureElementNonMutRec cenv parent typeNames endm (env: TcEnv) synS
             return env
 
 
-        | SynModuleSigDecl.NamespaceFragment (SynModuleOrNamespaceSig(longId, isRec, isModule, defs, xml, attribs, vis, m)) -> 
+        | SynModuleSigDecl.NamespaceFragment (SynModuleOrNamespaceSig(longId, isRec, kind, defs, xml, attribs, vis, m)) -> 
 
             do for id in longId do 
                  CheckNamespaceModuleOrTypeName cenv.g id
@@ -16725,7 +16724,7 @@ let rec TcSignatureElementNonMutRec cenv parent typeNames endm (env: TcEnv) synS
             //    namespace [rec] A.B
             //      module M = ...
             let enclosingNamespacePath, defs = 
-                if isModule then 
+                if kind.IsModule then 
                     let nsp, modName = List.frontAndBack longId
                     let modDecl = [SynModuleSigDecl.NestedModule(ComponentInfo(attribs, [], [], [modName], xml, false, vis, m), false, defs, m)] 
                     nsp, modDecl
@@ -17022,7 +17021,7 @@ let rec TcModuleOrNamespaceElementNonMutRec (cenv:cenv) parent typeNames scopem
               return ((fun modDefs -> modDefn :: modDefs), topAttrsNew), env, envAtEnd
       
 
-      | SynModuleDecl.NamespaceFragment(SynModuleOrNamespace(longId, isRec, isModule, defs, xml, attribs, vis, m)) ->
+      | SynModuleDecl.NamespaceFragment(SynModuleOrNamespace(longId, isRec, kind, defs, xml, attribs, vis, m)) ->
 
           if !progress then dprintn ("Typecheck implementation " + textOfLid longId)
           let endm = m.EndRange
@@ -17037,7 +17036,7 @@ let rec TcModuleOrNamespaceElementNonMutRec (cenv:cenv) parent typeNames scopem
           //    namespace [rec] A.B
           //      module M = ...
           let enclosingNamespacePath, defs = 
-              if isModule then 
+              if kind.IsModule then 
                   let nsp, modName = List.frontAndBack longId
                   let modDecl = [SynModuleDecl.NestedModule(ComponentInfo(attribs, [], [], [modName], xml, false, vis, m), false, defs, true, m)] 
                   nsp, modDecl
@@ -17388,7 +17387,7 @@ let CheckModuleSignature g cenv m denvAtEnd rootSigOpt implFileTypePriorToSig im
                     // Compute the remapping from implementation to signature
                     let remapInfo , _ = ComputeRemappingFromInferredSignatureToExplicitSignature cenv.g implFileTypePriorToSig sigFileType
                      
-                    let aenv = { TypeEquivEnv.Empty with EquivTycons = TyconRefMap.OfList remapInfo.mrpiEntities }
+                    let aenv = { TypeEquivEnv.Empty with EquivTycons = TyconRefMap.OfList remapInfo.RepackagedEntities }
                     
                     if not (SignatureConformance.Checker(cenv.g, cenv.amap, denv, remapInfo, true).CheckSignature  aenv (mkLocalModRef implFileSpecPriorToSig) sigFileType) then  (
                         // We can just raise 'ReportedError' since CheckModuleOrNamespace raises its own error 
diff --git a/src/fsharp/TypeChecker.fsi b/src/fsharp/TypeChecker.fsi
index 3f84e1992fc..aae09544998 100644
--- a/src/fsharp/TypeChecker.fsi
+++ b/src/fsharp/TypeChecker.fsi
@@ -39,14 +39,14 @@ val EmptyTopAttrs : TopAttribs
 val CombineTopAttrs : TopAttribs -> TopAttribs -> TopAttribs
 
 val TypeCheckOneImplFile : 
-      TcGlobals * NiceNameGenerator * ImportMap * CcuThunk * (unit -> bool) * ConditionalDefines * NameResolution.TcResultsSink * bool
+      TcGlobals * NiceNameGenerator * ImportMap * CcuThunk * (unit -> bool) * ConditionalDefines option * NameResolution.TcResultsSink * bool
       -> TcEnv 
       -> Tast.ModuleOrNamespaceType option
       -> ParsedImplFileInput
       -> Eventually<TopAttribs * Tast.TypedImplFile * ModuleOrNamespaceType * TcEnv * bool>
 
 val TypeCheckOneSigFile : 
-      TcGlobals * NiceNameGenerator * ImportMap * CcuThunk  * (unit -> bool) * ConditionalDefines * NameResolution.TcResultsSink * bool
+      TcGlobals * NiceNameGenerator * ImportMap * CcuThunk  * (unit -> bool) * ConditionalDefines option * NameResolution.TcResultsSink * bool
       -> TcEnv                             
       -> ParsedSigFileInput
       -> Eventually<TcEnv * ModuleOrNamespaceType * bool>
diff --git a/src/fsharp/ast.fs b/src/fsharp/ast.fs
index f7fbbdd6491..22b960d18c6 100644
--- a/src/fsharp/ast.fs
+++ b/src/fsharp/ast.fs
@@ -1409,7 +1409,7 @@ and
     SynModuleDecl =
     | ModuleAbbrev of ident:Ident * longId:LongIdent * range:range
     | NestedModule of SynComponentInfo * isRecursive:bool * SynModuleDecls * bool * range:range
-    | Let of bool * SynBinding list * range:range
+    | Let of isRecursive:bool * SynBinding list * range:range
     | DoExpr of SequencePointInfoForBinding * SynExpr * range:range
     | Types of SynTypeDefn list * range:range
     | Exception of SynExceptionDefn * range:range
@@ -1462,11 +1462,23 @@ and
 
 and SynModuleSigDecls = SynModuleSigDecl list
 
-/// SynModuleOrNamespace(lid,isRec,isModule,decls,xmlDoc,attribs,SynAccess,m)
+and
+    [<Struct>]
+    SynModuleOrNamespaceKind =
+        | NamedModule
+        | AnonModule
+        | DeclaredNamespace
+        | GlobalNamespace
+
+        member x.IsModule =
+            match x with
+            | NamedModule | AnonModule -> true
+            | _ -> false
+
 and
     [<NoEquality; NoComparison>]
     SynModuleOrNamespace =
-    | SynModuleOrNamespace of longId:LongIdent * isRecursive:bool * isModule:bool * decls:SynModuleDecls * xmlDoc:PreXmlDoc * attribs:SynAttributes * accessibility:SynAccess option * range:range
+    | SynModuleOrNamespace of longId:LongIdent * isRecursive:bool * kind:SynModuleOrNamespaceKind * decls:SynModuleDecls * xmlDoc:PreXmlDoc * attribs:SynAttributes * accessibility:SynAccess option * range:range
     member this.Range =
         match this with
         | SynModuleOrNamespace (range=m) -> m
@@ -1474,7 +1486,7 @@ and
 and
     [<NoEquality; NoComparison>]
     SynModuleOrNamespaceSig =
-    | SynModuleOrNamespaceSig of longId:LongIdent * isRecursive:bool * isModule:bool * SynModuleSigDecls * xmlDoc:PreXmlDoc * attribs:SynAttributes * accessibility:SynAccess option * range:range
+    | SynModuleOrNamespaceSig of longId:LongIdent * isRecursive:bool * kind:SynModuleOrNamespaceKind * SynModuleSigDecls * xmlDoc:PreXmlDoc * attribs:SynAttributes * accessibility:SynAccess option * range:range
 
 and [<NoEquality; NoComparison>]
     ParsedHashDirective =
@@ -1484,13 +1496,13 @@ and [<NoEquality; NoComparison>]
 type ParsedImplFileFragment =
     | AnonModule of SynModuleDecls * range:range
     | NamedModule of SynModuleOrNamespace
-    | NamespaceFragment of longId:LongIdent * bool * bool * SynModuleDecls * xmlDoc:PreXmlDoc * SynAttributes * range:range
+    | NamespaceFragment of longId:LongIdent * bool * SynModuleOrNamespaceKind * SynModuleDecls * xmlDoc:PreXmlDoc * SynAttributes * range:range
 
 [<NoEquality; NoComparison; RequireQualifiedAccess>]
 type ParsedSigFileFragment =
     | AnonModule of SynModuleSigDecls * range:range
     | NamedModule of SynModuleOrNamespaceSig
-    | NamespaceFragment of longId:LongIdent * bool * bool * SynModuleSigDecls * xmlDoc:PreXmlDoc * SynAttributes * range:range
+    | NamespaceFragment of longId:LongIdent * bool * SynModuleOrNamespaceKind * SynModuleSigDecls * xmlDoc:PreXmlDoc * SynAttributes * range:range
 
 [<NoEquality; NoComparison>]
 type ParsedFsiInteraction =
diff --git a/src/fsharp/fsc.fs b/src/fsharp/fsc.fs
index fa3831018ed..0880f5d1ac2 100644
--- a/src/fsharp/fsc.fs
+++ b/src/fsharp/fsc.fs
@@ -1773,11 +1773,9 @@ let main0(ctok, argv, legacyReferenceResolver, bannerAlreadyPrinted, reduceMemor
             errorRecoveryNoRange e
             exiter.Exit 1
     
-    let inputs =
-        // Deduplicate module names
-        let moduleNamesDict = ConcurrentDictionary<string,Set<string>>()
-        inputs
-        |> List.map (fun (input,x) -> DeduplicateParsedInputModuleName moduleNamesDict input,x)
+    let inputs, _ =
+        (Map.empty, inputs)
+        ||> List.mapFold (fun state (input,x) -> let inputT, stateT = DeduplicateParsedInputModuleName state input in (inputT,x), stateT)
 
     if tcConfig.parseOnly then exiter.Exit 0 
     if not tcConfig.continueAfterParseFailure then 
@@ -2036,7 +2034,7 @@ let main4 dynamicAssemblyCreator (Args (ctok, tcConfig,  tcImports: TcImports, t
 
     DoesNotRequireCompilerThreadTokenAndCouldPossiblyBeMadeConcurrent  ctok
 
-    let pdbfile = pdbfile |> Option.map (tcConfig.MakePathAbsolute >> Path.GetFullPath)
+    let pdbfile = pdbfile |> Option.map (tcConfig.MakePathAbsolute >> FileSystem.GetFullPathShim)
 
     let normalizeAssemblyRefs (aref:ILAssemblyRef) = 
         match tcImports.TryFindDllInfo (ctok, Range.rangeStartup, aref.Name, lookupOnly=false) with 
diff --git a/src/fsharp/Fsc/InternalsVisibleTo.fs b/src/fsharp/fsc/InternalsVisibleTo.fs
similarity index 100%
rename from src/fsharp/Fsc/InternalsVisibleTo.fs
rename to src/fsharp/fsc/InternalsVisibleTo.fs
diff --git a/src/fsharp/Fsc/app.config b/src/fsharp/fsc/app.config
similarity index 100%
rename from src/fsharp/Fsc/app.config
rename to src/fsharp/fsc/app.config
diff --git a/src/fsharp/Fsc/Fsc.fsproj b/src/fsharp/fsc/fsc.fsproj
similarity index 98%
rename from src/fsharp/Fsc/Fsc.fsproj
rename to src/fsharp/fsc/fsc.fsproj
index 90c7b05cda4..34498db1df7 100644
--- a/src/fsharp/Fsc/Fsc.fsproj
+++ b/src/fsharp/fsc/fsc.fsproj
@@ -12,6 +12,7 @@
     <OtherFlags>$(OtherFlags) --maxerrors:20 --extraoptimizationloops:1</OtherFlags>
     <UseFSharpProductVersion>true</UseFSharpProductVersion>
     <UseAssetTargetFallback>true</UseAssetTargetFallback>
+    <NGenBinary>true</NGenBinary>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/fsharp/fsi/fsi.fs b/src/fsharp/fsi/fsi.fs
index 07ddd0e395a..bc0091251b0 100644
--- a/src/fsharp/fsi/fsi.fs
+++ b/src/fsharp/fsi/fsi.fs
@@ -1155,7 +1155,7 @@ type internal FsiDynamicCompiler
         let i = nextFragmentId()
         let prefix = mkFragmentPath i
         let prefixPath = pathOfLid prefix
-        let impl = SynModuleOrNamespace(prefix,(*isRec*)false, (* isModule: *) true,defs,PreXmlDoc.Empty,[],None,rangeStdin)
+        let impl = SynModuleOrNamespace(prefix,(*isRec*)false, NamedModule,defs,PreXmlDoc.Empty,[],None,rangeStdin)
         let input = ParsedInput.ImplFile(ParsedImplFileInput(filename,true, ComputeQualifiedNameOfFileFromUniquePath (rangeStdin,prefixPath),[],[],[impl],(true (* isLastCompiland *), false (* isExe *)) ))
         let istate,tcEnvAtEndOfLastInput,declaredImpls = ProcessInputs (ctok, errorLogger, istate, [input], showTypes, true, isInteractiveItExpr, prefix)
         let tcState = istate.tcState 
diff --git a/src/fsharp/fsi/Fsi.fsproj b/src/fsharp/fsi/fsi.fsproj
similarity index 92%
rename from src/fsharp/fsi/Fsi.fsproj
rename to src/fsharp/fsi/fsi.fsproj
index 93b70873742..29916135ac0 100644
--- a/src/fsharp/fsi/Fsi.fsproj
+++ b/src/fsharp/fsi/fsi.fsproj
@@ -4,7 +4,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFrameworks>net472;netcoreapp2.0</TargetFrameworks>
+    <TargetFrameworks>net472;netcoreapp2.1</TargetFrameworks>
     <TargetExt>.exe</TargetExt>
     <AssemblyName>fsi</AssemblyName>
     <NoWarn>$(NoWarn);45;55;62;75;1204</NoWarn>
@@ -13,6 +13,7 @@
     <Win32Resource>fsi.res</Win32Resource>
     <UseFSharpProductVersion>true</UseFSharpProductVersion>
     <UseAssetTargetFallback>true</UseAssetTargetFallback>
+    <NGenBinary>true</NGenBinary>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(TargetFramework)' == 'net472'">
@@ -28,10 +29,10 @@
   <ItemGroup>
     <ProjectReference Include="..\FSharp.Core\FSharp.Core.fsproj" />
     <ProjectReference Include="..\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj" />
+    <ProjectReference Include="..\FSharp.Compiler.Interactive.Settings\FSharp.Compiler.Interactive.Settings.fsproj" />
 
     <!-- only used when '$(TargetFramework)' == 'netstandard2.0' -->
     <ProjectReference Include="..\FSharp.Build\FSharp.Build.fsproj" Condition="'$(TargetFramework)' == 'netstandard2.0'" />
-    <ProjectReference Include="..\FSharp.Compiler.Interactive.Settings\FSharp.Compiler.Interactive.Settings.fsproj" Condition="'$(TargetFramework)' == 'netstandard2.0'" />
 
     <!-- only used when '$(TargetFramework)' == 'net46' -->
     <ProjectReference Include="..\FSharp.Compiler.Server.Shared\FSharp.Compiler.Server.Shared.fsproj" Condition="'$(TargetFramework)' == 'net472'" />
@@ -45,7 +46,7 @@
     <Reference Include="WindowsBase" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp2.0'">
+  <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp2.1'">
     <PackageReference Include="System.Diagnostics.Process" Version="$(SystemDiagnosticsProcessPackageVersion)" />
     <PackageReference Include="System.Linq.Expressions" Version="$(SystemLinqExpressionsPackageVersion)" />
     <PackageReference Include="System.Reflection.Emit" Version="$(SystemReflectionEmitPackageVersion)" />
diff --git a/src/fsharp/fsiAnyCpu/FsiAnyCPU.fsproj b/src/fsharp/fsiAnyCpu/fsiAnyCpu.fsproj
similarity index 93%
rename from src/fsharp/fsiAnyCpu/FsiAnyCPU.fsproj
rename to src/fsharp/fsiAnyCpu/fsiAnyCpu.fsproj
index 6f47292d9d7..98132bf3c27 100644
--- a/src/fsharp/fsiAnyCpu/FsiAnyCPU.fsproj
+++ b/src/fsharp/fsiAnyCpu/fsiAnyCpu.fsproj
@@ -29,6 +29,7 @@
   <ItemGroup>
     <ProjectReference Include="..\FSharp.Core\FSharp.Core.fsproj" />
     <ProjectReference Include="..\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj" />
+    <ProjectReference Include="..\FSharp.Compiler.Interactive.Settings\FSharp.Compiler.Interactive.Settings.fsproj" />
     <ProjectReference Include="..\FSharp.Compiler.Server.Shared\FSharp.Compiler.Server.Shared.fsproj" />
   </ItemGroup>
 
diff --git a/src/fsharp/pars.fsy b/src/fsharp/pars.fsy
index de42111b414..b03987165bb 100644
--- a/src/fsharp/pars.fsy
+++ b/src/fsharp/pars.fsy
@@ -675,14 +675,14 @@ fileModuleSpec:
       (fun (isRec2,path,_) -> 
         if not (isNil path) then errorR(Error(FSComp.SR.parsNamespaceOrModuleNotBoth(),m2))
         let lid = path@path2 
-        ParsedSigFileFragment.NamedModule(SynModuleOrNamespaceSig(lid, (isRec || isRec2), true, $4, xml,$1,vis,m)))  }
+        ParsedSigFileFragment.NamedModule(SynModuleOrNamespaceSig(lid, (isRec || isRec2), NamedModule, $4, xml,$1,vis,m)))  }
 
   | moduleSpfnsPossiblyEmptyBlock 
     { let m = (rhs parseState 1) 
       (fun (isRec, path, xml) -> 
         match path with 
         | [] -> ParsedSigFileFragment.AnonModule($1, m)  
-        | _ -> ParsedSigFileFragment.NamespaceFragment(path, isRec, false, $1, xml,[],m))  } 
+        | _ -> ParsedSigFileFragment.NamespaceFragment(path, isRec, DeclaredNamespace, $1, xml,[],m))  } 
 
 
 moduleSpfnsPossiblyEmptyBlock: 
@@ -1097,14 +1097,14 @@ fileModuleImpl:
       (fun (isRec, path, _) -> 
         if not (isNil path) then errorR(Error(FSComp.SR.parsNamespaceOrModuleNotBoth(),m2))
         let lid = path@path2 
-        ParsedImplFileFragment.NamedModule(SynModuleOrNamespace(lid, (isRec || isRec2), true, $4, xml,$1,vis,m))) }
+        ParsedImplFileFragment.NamedModule(SynModuleOrNamespace(lid, (isRec || isRec2), NamedModule, $4, xml,$1,vis,m))) }
 
   | moduleDefnsOrExprPossiblyEmptyOrBlock 
     { let m = (rhs parseState 1) 
       (fun (isRec, path, xml) -> 
         match path with 
         | [] -> ParsedImplFileFragment.AnonModule($1,m)  
-        | _ -> ParsedImplFileFragment.NamespaceFragment(path, isRec, false, $1, xml,[],m)) } 
+        | _ -> ParsedImplFileFragment.NamespaceFragment(path, isRec, DeclaredNamespace, $1, xml,[],m)) } 
 
 
 /* A collection/block of definitions or expressions making up a module or namespace, possibly empty */
diff --git a/src/fsharp/range.fs b/src/fsharp/range.fs
index c208eee8e1e..485f5882354 100755
--- a/src/fsharp/range.fs
+++ b/src/fsharp/range.fs
@@ -15,17 +15,20 @@ type FileIndex = int32
 
 [<Literal>]
 let columnBitCount = 20
+
 [<Literal>]
 let lineBitCount = 31
 
 let posBitCount = lineBitCount + columnBitCount
-let _ = assert (posBitCount <= 64)
+
 let posColumnMask  = mask64 0 columnBitCount
+
 let lineColumnMask = mask64 columnBitCount lineBitCount
 
 [<Struct; CustomEquality; NoComparison>]
 [<System.Diagnostics.DebuggerDisplay("{Line},{Column}")>]
 type pos(code:int64) =
+
     new (l, c) = 
         let l = max 0 l 
         let c = max 0 c 
@@ -34,63 +37,80 @@ type pos(code:int64) =
         pos p
 
     member p.Line = int32 (uint64 code >>> columnBitCount)
+
     member p.Column = int32 (code &&& posColumnMask)
 
     member r.Encoding = code
+
     static member EncodingSize = posBitCount
+
     static member Decode (code:int64) : pos = pos code
+
     override p.Equals(obj) = match obj with :? pos as p2 -> code = p2.Encoding | _ -> false
+
     override p.GetHashCode() = hash code
+
     override p.ToString() = sprintf "(%d,%d)" p.Line p.Column
 
 [<Literal>]
 let fileIndexBitCount = 24
+
 [<Literal>]
 let startColumnBitCount = columnBitCount // 20
+
 [<Literal>]
 let endColumnBitCount = columnBitCount // 20
 
 [<Literal>]
 let startLineBitCount = lineBitCount // 31
+
 [<Literal>]
 let heightBitCount = 27
+
 [<Literal>]
 let isSyntheticBitCount = 1
-#if DEBUG
-let _ = assert (fileIndexBitCount + startColumnBitCount + endColumnBitCount <= 64)
-let _ = assert (startLineBitCount + heightBitCount + isSyntheticBitCount <= 64)
-#endif
- 
+
 [<Literal>]
 let fileIndexShift   = 0 
+
 [<Literal>]
 let startColumnShift = 24
+
 [<Literal>]
 let endColumnShift   = 44
 
 [<Literal>]
 let startLineShift   = 0
+
 [<Literal>]
 let heightShift      = 31
+
 [<Literal>]
 let isSyntheticShift = 58
 
-
 [<Literal>]
 let fileIndexMask =   0b0000000000000000000000000000000000000000111111111111111111111111L
+
 [<Literal>]
 let startColumnMask = 0b0000000000000000000011111111111111111111000000000000000000000000L
+
 [<Literal>]
 let endColumnMask =   0b1111111111111111111100000000000000000000000000000000000000000000L
 
 [<Literal>]
 let startLineMask =   0b0000000000000000000000000000000001111111111111111111111111111111L
+
 [<Literal>]
 let heightMask =      0b0000001111111111111111111111111110000000000000000000000000000000L
+
 [<Literal>]
 let isSyntheticMask = 0b0000010000000000000000000000000000000000000000000000000000000000L
 
 #if DEBUG
+let _ = assert (posBitCount <= 64)
+let _ = assert (fileIndexBitCount + startColumnBitCount + endColumnBitCount <= 64)
+let _ = assert (startLineBitCount + heightBitCount + isSyntheticBitCount <= 64)
+
 let _ = assert (startColumnShift   = fileIndexShift   + fileIndexBitCount)
 let _ = assert (endColumnShift = startColumnShift   + startColumnBitCount)
 
@@ -105,24 +125,64 @@ let _ = assert (endColumnMask =   mask64 endColumnShift   endColumnBitCount)
 let _ = assert (isSyntheticMask = mask64 isSyntheticShift isSyntheticBitCount)
 #endif
 
-// This is just a standard unique-index table
+/// Removes relative parts from any full paths
+let normalizeFilePath (filePath: string) = 
+    try 
+        if FileSystem.IsPathRootedShim filePath then 
+            FileSystem.GetFullPathShim filePath
+        else
+            filePath
+    with _ -> filePath
+
+/// A unique-index table for file names.
 type FileIndexTable() = 
     let indexToFileTable = new ResizeArray<_>(11)
     let fileToIndexTable = new ConcurrentDictionary<string, int>()
-    member t.FileToIndex f = 
-        let mutable res = 0 
-        let ok = fileToIndexTable.TryGetValue(f, &res) 
-        if ok then res 
-        else
+
+    // Note: we should likely adjust this code to always normalize. However some testing (and possibly some
+    // product behaviour) appears to be sensitive to error messages reporting un-normalized file names.
+    // Currently all names going through 'mkRange' get normalized, while this going through just 'fileIndexOfFile'
+    // do not.  Also any file names which are not put into ranges at all are non-normalized.
+    //
+    // TO move forward we should eventually introduce a new type NormalizedFileName that tracks this invariant.
+    member t.FileToIndex normalize filePath = 
+        match fileToIndexTable.TryGetValue(filePath) with 
+        | true, idx -> idx
+        | _ -> 
+        
+        // Try again looking for a normalized entry.
+        let normalizedFilePath = if normalize then normalizeFilePath filePath else filePath
+        match fileToIndexTable.TryGetValue(normalizedFilePath) with 
+        | true, idx ->
+            // Record the non-normalized entry if necessary
+            if filePath <> normalizedFilePath then 
+                lock fileToIndexTable (fun () -> 
+                    fileToIndexTable.[filePath] <- idx)
+                    
+            // Return the index
+            idx
+            
+        | _ -> 
             lock fileToIndexTable (fun () -> 
-                let n = indexToFileTable.Count in
-                indexToFileTable.Add(f)
-                fileToIndexTable.[f] <- n
-                n)
+                // Get the new index
+                let idx = indexToFileTable.Count
+                
+                // Record the normalized entry
+                indexToFileTable.Add normalizedFilePath
+                fileToIndexTable.[normalizedFilePath] <- idx
+                
+                // Record the non-normalized entry if necessary
+                if filePath <> normalizedFilePath then 
+                    fileToIndexTable.[filePath] <- idx
+
+                // Return the index
+                idx)
 
     member t.IndexToFile n = 
-        (if n < 0 then failwithf "fileOfFileIndex: negative argument: n = %d\n" n)
-        (if n >= indexToFileTable.Count then failwithf "fileOfFileIndex: invalid argument: n = %d\n" n)
+        if n < 0 then 
+            failwithf "fileOfFileIndex: negative argument: n = %d\n" n
+        if n >= indexToFileTable.Count then
+            failwithf "fileOfFileIndex: invalid argument: n = %d\n" n
         indexToFileTable.[n]
 
 let maxFileIndex = pown32 fileIndexBitCount
@@ -132,8 +192,11 @@ let maxFileIndex = pown32 fileIndexBitCount
 let fileIndexTable = new FileIndexTable()
 
 // If we exceed the maximum number of files we'll start to report incorrect file names
-let fileIndexOfFile f = fileIndexTable.FileToIndex(f) % maxFileIndex 
-let fileOfFileIndex n = fileIndexTable.IndexToFile(n)
+let fileIndexOfFileAux normalize f = fileIndexTable.FileToIndex normalize f % maxFileIndex 
+
+let fileIndexOfFile filePath = fileIndexOfFileAux false filePath 
+
+let fileOfFileIndex idx = fileIndexTable.IndexToFile idx
 
 let mkPos l c = pos (l, c)
 
@@ -157,19 +220,31 @@ type range(code1:int64, code2: int64) =
     new (fidx, b:pos, e:pos) = range(fidx, b.Line, b.Column, e.Line, e.Column)
 
     member r.StartLine   = int32((code2 &&& startLineMask)   >>> startLineShift)
+
     member r.StartColumn = int32((code1 &&& startColumnMask) >>> startColumnShift) 
+
     member r.EndLine     = int32((code2 &&& heightMask)      >>> heightShift) + r.StartLine
+
     member r.EndColumn   = int32((code1 &&& endColumnMask)   >>> endColumnShift)
+
     member r.IsSynthetic = int32((code2 &&& isSyntheticMask) >>> isSyntheticShift) <> 0 
+
     member r.Start = pos (r.StartLine, r.StartColumn)
+
     member r.End = pos (r.EndLine, r.EndColumn)
+
     member r.FileIndex = int32(code1 &&& fileIndexMask)
+
     member m.StartRange = range (m.FileIndex, m.Start, m.Start)
+
     member m.EndRange = range (m.FileIndex, m.End, m.End)
+
     member r.FileName = fileOfFileIndex r.FileIndex
+
     member r.MakeSynthetic() = range(code1, code2 ||| isSyntheticMask)
 
     member r.Code1 = code1
+
     member r.Code2 = code2
 
 #if DEBUG
@@ -194,33 +269,31 @@ type range(code1:int64, code2: int64) =
 
     override r.ToString() = sprintf "%s (%d,%d--%d,%d) IsSynthetic=%b" r.FileName r.StartLine r.StartColumn r.EndLine r.EndColumn r.IsSynthetic
 
-let mkRange f b e =
-    // remove relative parts from full path
-    let normalizedFilePath = if Path.IsPathRooted f then try Path.GetFullPath f with _ -> f else f
-    range (fileIndexOfFile normalizedFilePath, b, e)
+let mkRange filePath startPos endPos = range (fileIndexOfFileAux true filePath, startPos, endPos)
 
 let equals (r1: range) (r2: range) =
     r1.Code1 = r2.Code1 && r1.Code2 = r2.Code2
 
-let mkFileIndexRange fi b e = range (fi, b, e)
+let mkFileIndexRange fileIndex startPos endPos = range (fileIndex, startPos, endPos)
 
-(* end representation, start derived ops *)
-                 
 let posOrder   = Order.orderOn (fun (p:pos) -> p.Line, p.Column) (Pair.order (Int32.order, Int32.order))
-(* rangeOrder: not a total order, but enough to sort on ranges *)      
+
+/// rangeOrder: not a total order, but enough to sort on ranges
 let rangeOrder = Order.orderOn (fun (r:range) -> r.FileName, r.Start) (Pair.order (String.order, posOrder))
 
 let outputPos   (os:TextWriter) (m:pos)   = fprintf os "(%d,%d)" m.Line m.Column
+
 let outputRange (os:TextWriter) (m:range) = fprintf os "%s%a-%a" m.FileName outputPos m.Start outputPos m.End
-let boutputPos   os (m:pos)   = bprintf os "(%d,%d)" m.Line m.Column
-let boutputRange os (m:range) = bprintf os "%s%a-%a" m.FileName boutputPos m.Start boutputPos m.End
     
 let posGt (p1:pos) (p2:pos) = (p1.Line > p2.Line || (p1.Line = p2.Line && p1.Column > p2.Column))
+
 let posEq (p1:pos) (p2:pos) = (p1.Line = p2.Line &&  p1.Column = p2.Column)
+
 let posGeq p1 p2 = posEq p1 p2 || posGt p1 p2
+
 let posLt p1 p2 = posGt p2 p1
 
-// This is deliberately written in an allocation-free way, i.e. m1.Start, m1.End etc. are not called
+/// This is deliberately written in an allocation-free way, i.e. m1.Start, m1.End etc. are not called
 let unionRanges (m1:range) (m2:range) = 
     if m1.FileIndex <> m2.FileIndex then m2 else
     let b = 
@@ -244,9 +317,13 @@ let rangeBeforePos (m1:range) p =
     posGeq p m1.End
 
 let rangeN filename line = mkRange filename (mkPos line 0) (mkPos line 0)
+
 let pos0 = mkPos 1 0
+
 let range0 =  rangeN "unknown" 1
+
 let rangeStartup = rangeN "startup" 1
+
 let rangeCmdArgs = rangeN "commandLineArgs" 0
 
 let trimRangeToLine (r:range) =
@@ -260,6 +337,7 @@ let trimRangeToLine (r:range) =
 
 (* For Diagnostics *)
 let stringOfPos   (pos:pos) = sprintf "(%d,%d)" pos.Line pos.Column
+
 let stringOfRange (r:range) = sprintf "%s%s-%s" r.FileName (stringOfPos r.Start) (stringOfPos r.End)
 
 #if CHECK_LINE0_TYPES // turn on to check that we correctly transform zero-based line counts to one-based line counts
@@ -274,17 +352,22 @@ type Pos01 = Line0 * int
 type Range01 = Pos01 * Pos01
 
 module Line =
+
     // Visual Studio uses line counts starting at 0, F# uses them starting at 1 
     let fromZ (line:Line0) = int line+1
+
     let toZ (line:int) : Line0 = LanguagePrimitives.Int32WithMeasure(line - 1)
 
 module Pos =
+
     let fromZ (line:Line0) idx = mkPos (Line.fromZ line) idx 
-    let toZ (p:pos) = (Line.toZ p.Line, p.Column)
 
+    let toZ (p:pos) = (Line.toZ p.Line, p.Column)
 
 module Range =
+
     let toZ (m:range) = Pos.toZ m.Start, Pos.toZ m.End
+
     let toFileZ (m:range) = m.FileName, toZ m
 
 
diff --git a/src/fsharp/range.fsi b/src/fsharp/range.fsi
index 53deaca0e27..6549b008dcf 100755
--- a/src/fsharp/range.fsi
+++ b/src/fsharp/range.fsi
@@ -10,44 +10,86 @@ open Microsoft.FSharp.Compiler.AbstractIL.Internal
 open Microsoft.FSharp.Compiler  
 
   
-(* we keep a global tables of filenames that we can reference by integers *)
+/// An index into a global tables of filenames
 type FileIndex = int32 
-val fileIndexOfFile : string -> FileIndex
+
+/// Convert a file path to an index
+val fileIndexOfFile : filePath: string -> FileIndex
+
+/// Convert an index into a file path
 val fileOfFileIndex : FileIndex -> string
 
+/// Represents a position in a file
 [<Struct; CustomEquality; NoComparison>]
 type pos =
+
+    /// The line number for the position
     member Line : int
+
+    /// The column number for the position
     member Column : int
 
+    /// The encoding of the position as a 64-bit integer
     member Encoding : int64
+
+    /// Decode a position fro a 64-bit integer
     static member Decode : int64 -> pos
+
     /// The maximum number of bits needed to store an encoded position 
     static member EncodingSize : int
   
 /// Create a position for the given line and column
 val mkPos : line:int -> column:int -> pos
 
+/// Ordering on positions
 val posOrder : IComparer<pos>
 
+/// Represents a range within a known file
 [<Struct; CustomEquality; NoComparison>]
 type range =
+
+    /// The start line of the range
     member StartLine : int
+
+    /// The start column of the range
     member StartColumn : int
+
+    /// The line number for the end position of the range
     member EndLine : int
+
+    /// The column number for the end position of the range
     member EndColumn : int
+
+    /// The start position of the range
     member Start : pos
+
+    /// The end position of the range
     member End : pos
+
+    /// The empty range that is located at the start position of the range
     member StartRange: range
+
+    /// The empty range that is located at the end position of the range
     member EndRange: range
+
+    /// The file index for the range
     member FileIndex : int
+
+    /// The file name for the file of the range
     member FileName : string
+
     /// Synthetic marks ranges which are produced by intermediate compilation phases. This
     /// bit signifies that the range covers something that should not be visible to language
     /// service operations like dot-completion.
     member IsSynthetic : bool 
+
+    /// Convert a range to be synthetic
     member MakeSynthetic : unit -> range
+
+    /// Convert a range to string
     member ToShortString : unit -> string
+
+    /// The range where all values are zero
     static member Zero : range
   
 /// This view of range marks uses file indexes explicitly 
@@ -58,34 +100,61 @@ val mkRange : string -> pos -> pos -> range
 
 val equals : range -> range -> bool
 
+/// Reduce a range so it only covers a line
 val trimRangeToLine : range -> range
 
 /// not a total order, but enough to sort on ranges 
 val rangeOrder : IComparer<range>
 
+/// Output a position
 val outputPos : System.IO.TextWriter -> pos -> unit
+
+/// Output a range
 val outputRange : System.IO.TextWriter -> range -> unit
-val boutputPos : StringBuilder -> pos -> unit
-val boutputRange : StringBuilder -> range -> unit
     
+/// Compare positions for less-than
 val posLt : pos -> pos -> bool
+
+/// Compare positions for greater-than
 val posGt : pos -> pos -> bool
+
+/// Compare positions for equality
 val posEq : pos -> pos -> bool
+
+/// Compare positions for greater-than-or-equal-to
 val posGeq : pos -> pos -> bool
 
+/// Union two ranges, taking their first occurring start position and last occurring end position
 val unionRanges : range -> range -> range
+
+/// Test to see if one range contains another range
 val rangeContainsRange : range -> range -> bool
+
+/// Test to see if a range contains a position
 val rangeContainsPos : range -> pos -> bool
+
+/// Test to see if a range occurs fully before a position
 val rangeBeforePos : range -> pos -> bool
 
+/// Make a dummy range for a file
 val rangeN : string -> int -> range
+
+/// The zero position
 val pos0 : pos
+
+/// The zero range
 val range0 : range
+
+/// A range associated with a dummy file called "startup"
 val rangeStartup : range
+
+/// A range associated with a dummy file for the command line arguments
 val rangeCmdArgs : range
  
-(* For diagnostics *)  
+/// Convert a position to a string
 val stringOfPos   : pos   -> string
+
+/// Convert a range to a string
 val stringOfRange : range -> string
 
 /// Represents a line number when using zero-based line counting (used by Visual Studio)
@@ -100,22 +169,30 @@ type Line0 = int
 
 /// Represents a position using zero-based line counting (used by Visual Studio)
 type Pos01 = Line0 * int
+
 /// Represents a range using zero-based line counting (used by Visual Studio)
 type Range01 = Pos01 * Pos01
 
 module Line =
+
     /// Convert a line number from zero-based line counting (used by Visual Studio) to one-based line counting (used internally in the F# compiler and in F# error messages) 
     val fromZ : Line0 -> int
+
     /// Convert a line number from one-based line counting (used internally in the F# compiler and in F# error messages) to zero-based line counting (used by Visual Studio)
     val toZ : int -> Line0 
 
 module Pos =
+
     /// Convert a position from zero-based line counting (used by Visual Studio) to one-based line counting (used internally in the F# compiler and in F# error messages) 
     val fromZ : line:Line0 -> column:int -> pos
+
     /// Convert a position from one-based line counting (used internally in the F# compiler and in F# error messages) to zero-based line counting (used by Visual Studio)
     val toZ : pos -> Pos01
 
 module Range =
+
     /// Convert a range from one-based line counting (used internally in the F# compiler and in F# error messages) to zero-based line counting (used by Visual Studio)
     val toZ : range -> Range01
+
+    /// Convert a range from one-based line counting (used internally in the F# compiler and in F# error messages) to zero-based line counting (used by Visual Studio)
     val toFileZ : range -> string * Range01
diff --git a/src/fsharp/service/IncrementalBuild.fs b/src/fsharp/service/IncrementalBuild.fs
index 37c4b16bf21..f5d0141b32e 100755
--- a/src/fsharp/service/IncrementalBuild.fs
+++ b/src/fsharp/service/IncrementalBuild.fs
@@ -55,15 +55,16 @@ module internal IncrementalBuild =
         /// Get the Id for the given ScalarBuildRule.
         member  x.Id = 
             match x with
-            | ScalarInput(id, _) ->id
-            | ScalarDemultiplex(id, _, _, _) ->id
-            | ScalarMap(id, _, _, _) ->id
+            | ScalarInput(id, _) -> id
+            | ScalarDemultiplex(id, _, _, _) -> id
+            | ScalarMap(id, _, _, _) -> id
+
         /// Get the Name for the givenScalarExpr.
         member x.Name = 
             match x with 
-            | ScalarInput(_, n) ->n                
-            | ScalarDemultiplex(_, n, _, _) ->n
-            | ScalarMap(_, n, _, _) ->n                
+            | ScalarInput(_, n) -> n                
+            | ScalarDemultiplex(_, n, _, _) -> n
+            | ScalarMap(_, n, _, _) -> n                
 
     /// A build rule with a vector of outputs
     and VectorBuildRule = 
@@ -1034,6 +1035,7 @@ type TypeCheckAccumulator =
 
       /// Accumulated 'open' declarations, last file first
       tcOpenDeclarationsRev: OpenDeclaration[] list
+
       topAttribs:TopAttribs option
 
       /// Result of checking most recent file, if any
@@ -1043,6 +1045,9 @@ type TypeCheckAccumulator =
 
       tcDependencyFiles: string list
 
+      /// Disambiguation table for module names
+      tcModuleNamesDict: ModuleNamesDict
+
       /// Accumulated errors, last file first
       tcErrorsRev:(PhasedDiagnostic * FSharpErrorSeverity)[] list }
 
@@ -1125,10 +1130,17 @@ type PartialCheckResults =
       /// Kept in a stack so that each incremental update shares storage with previous files
       TcOpenDeclarationsRev: OpenDeclaration[] list
 
+      /// Disambiguation table for module names
+      ModuleNamesDict: ModuleNamesDict
+
       TcDependencyFiles: string list 
+
       TopAttribs: TopAttribs option
+
       TimeStamp: DateTime
+
       LatestImplementationFile: TypedImplFile option 
+
       LastestCcuSigForFile: ModuleOrNamespaceType option }
 
     member x.TcErrors  = Array.concat (List.rev x.TcErrorsRev)
@@ -1146,6 +1158,7 @@ type PartialCheckResults =
           TcOpenDeclarationsRev = tcAcc.tcOpenDeclarationsRev
           TcDependencyFiles = tcAcc.tcDependencyFiles
           TopAttribs = tcAcc.topAttribs
+          ModuleNamesDict = tcAcc.tcModuleNamesDict
           TimeStamp = timestamp 
           LatestImplementationFile = tcAcc.latestImplFile 
           LastestCcuSigForFile = tcAcc.latestCcuSigForFile }
@@ -1175,7 +1188,9 @@ type RawFSharpAssemblyDataBackedByLanguageService (tcConfig, tcGlobals, tcState:
             yield (ccuName, (fun () -> r.GetBytes())) ]
 
     let autoOpenAttrs = topAttrs.assemblyAttrs |> List.choose (List.singleton >> TryFindFSharpStringAttribute tcGlobals tcGlobals.attrib_AutoOpenAttribute)
+
     let ivtAttrs = topAttrs.assemblyAttrs |> List.choose (List.singleton >> TryFindFSharpStringAttribute tcGlobals tcGlobals.attrib_InternalsVisibleToAttribute)
+
     interface IRawFSharpAssemblyData with 
         member __.GetAutoOpenAttributes(_ilg) = autoOpenAttrs
         member __.GetInternalsVisibleToAttributes(_ilg) =  ivtAttrs
@@ -1246,6 +1261,7 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
     let assertNotDisposed() =
         if disposed then  
             System.Diagnostics.Debug.Assert(false, "IncrementalBuild object has already been disposed!")
+
     let mutable referenceCount = 0
 
     //----------------------------------------------------
@@ -1258,14 +1274,9 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
         assertNotDisposed()
         cache.GetFileTimeStamp filename
 
-    // Deduplicate module names
-    let moduleNamesDict = ConcurrentDictionary<string, Set<string>>()
-                            
     /// This is a build task function that gets placed into the build rules as the computation for a VectorMap
     ///
-    /// Parse the given files and return the given inputs. This function is expected to be
-    /// able to be called with a subset of sourceFiles and return the corresponding subset of
-    /// parsed inputs. 
+    /// Parse the given file and return the given input.
     let ParseTask ctok (sourceRange:range, filename:string, isLastCompiland) =
         assertNotDisposed()
         DoesNotRequireCompilerThreadTokenAndCouldPossiblyBeMadeConcurrent  ctok
@@ -1278,9 +1289,8 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
             IncrementalBuilderEventTesting.MRU.Add(IncrementalBuilderEventTesting.IBEParsed filename)
             let input = ParseOneInputFile(tcConfig, lexResourceManager, [], filename , isLastCompiland, errorLogger, (*retryLocked*)true)
             fileParsed.Trigger (filename)
-            let result = Option.map (DeduplicateParsedInputModuleName moduleNamesDict) input
 
-            result, sourceRange, filename, errorLogger.GetErrors ()
+            input, sourceRange, filename, errorLogger.GetErrors ()
         with exn -> 
             let msg = sprintf "unexpected failure in IncrementalFSharpBuild.Parse\nerror = %s" (exn.ToString())
             System.Diagnostics.Debug.Assert(false, msg)
@@ -1357,7 +1367,8 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
               latestImplFile=None
               latestCcuSigForFile=None
               tcDependencyFiles=basicDependencies
-              tcErrorsRev = [ initialErrors ] }   
+              tcErrorsRev = [ initialErrors ] 
+              tcModuleNamesDict = Map.empty }   
         return tcAcc }
                 
     /// This is a build task function that gets placed into the build rules as the computation for a Vector.ScanLeft
@@ -1378,6 +1389,8 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
                     let sink = TcResultsSinkImpl(tcAcc.tcGlobals)
                     let hadParseErrors = not (Array.isEmpty parseErrors)
 
+                    let input, moduleNamesDict = DeduplicateParsedInputModuleName tcAcc.tcModuleNamesDict input
+
                     let! (tcEnvAtEndOfFile, topAttribs, implFile, ccuSigForFile), tcState = 
                         TypeCheckOneInputEventually 
                             ((fun () -> hadParseErrors || errorLogger.ErrorCount > 0), 
@@ -1406,6 +1419,7 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
                                        tcSymbolUsesRev=tcSymbolUses :: tcAcc.tcSymbolUsesRev
                                        tcOpenDeclarationsRev = sink.GetOpenDeclarations() :: tcAcc.tcOpenDeclarationsRev
                                        tcErrorsRev = newErrors :: tcAcc.tcErrorsRev 
+                                       tcModuleNamesDict = moduleNamesDict
                                        tcDependencyFiles = filename :: tcAcc.tcDependencyFiles } 
                 }
                     
@@ -1448,55 +1462,55 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
             TypeCheckMultipleInputsFinish (results, finalAcc.tcState)
   
         let ilAssemRef, tcAssemblyDataOpt, tcAssemblyExprOpt = 
-          try
-           // TypeCheckClosedInputSetFinish fills in tcState.Ccu but in incremental scenarios we don't want this, 
-           // so we make this temporary here
-           let oldContents = tcState.Ccu.Deref.Contents
-           try
-            let tcState, tcAssemblyExpr = TypeCheckClosedInputSetFinish (mimpls, tcState)
-
-            // Compute the identity of the generated assembly based on attributes, options etc.
-            // Some of this is duplicated from fsc.fs
-            let ilAssemRef = 
-                let publicKey = 
-                    try 
-                        let signingInfo = Driver.ValidateKeySigningAttributes (tcConfig, tcGlobals, topAttrs)
-                        match Driver.GetStrongNameSigner signingInfo with 
-                        | None -> None
-                        | Some s -> Some (PublicKey.KeyAsToken(s.PublicKey))
-                    with e -> 
-                        errorRecoveryNoRange e
-                        None
-                let locale = TryFindFSharpStringAttribute tcGlobals (tcGlobals.FindSysAttrib  "System.Reflection.AssemblyCultureAttribute") topAttrs.assemblyAttrs
-                let assemVerFromAttrib = 
-                    TryFindFSharpStringAttribute tcGlobals (tcGlobals.FindSysAttrib "System.Reflection.AssemblyVersionAttribute") topAttrs.assemblyAttrs 
-                    |> Option.bind  (fun v -> try Some (parseILVersion v) with _ -> None)
-                let ver = 
-                    match assemVerFromAttrib with 
-                    | None -> tcConfig.version.GetVersionInfo(tcConfig.implicitIncludeDir)
-                    | Some v -> v
-                ILAssemblyRef.Create(assemblyName, None, publicKey, false, Some ver, locale)
-                
-            let tcAssemblyDataOpt = 
+            try
+                // TypeCheckClosedInputSetFinish fills in tcState.Ccu but in incremental scenarios we don't want this, 
+                // so we make this temporary here
+                let oldContents = tcState.Ccu.Deref.Contents
                 try
-                  // Assemblies containing type provider components can not successfully be used via cross-assembly references.
-                  // We return 'None' for the assembly portion of the cross-assembly reference 
-                  let hasTypeProviderAssemblyAttrib = 
-                      topAttrs.assemblyAttrs |> List.exists (fun (Attrib(tcref, _, _, _, _, _, _)) -> tcref.CompiledRepresentationForNamedType.BasicQualifiedName = typeof<Microsoft.FSharp.Core.CompilerServices.TypeProviderAssemblyAttribute>.FullName)
-                  if tcState.CreatesGeneratedProvidedTypes || hasTypeProviderAssemblyAttrib then
-                    None
-                  else
-                    Some  (RawFSharpAssemblyDataBackedByLanguageService (tcConfig, tcGlobals, tcState, outfile, topAttrs, assemblyName, ilAssemRef) :> IRawFSharpAssemblyData)
-
-                with e -> 
-                    errorRecoveryNoRange e
-                    None
-            ilAssemRef, tcAssemblyDataOpt, Some tcAssemblyExpr
-            finally 
-                tcState.Ccu.Deref.Contents <- oldContents
-          with e -> 
-            errorRecoveryNoRange e
-            mkSimpleAssemblyRef assemblyName, None, None
+                    let tcState, tcAssemblyExpr = TypeCheckClosedInputSetFinish (mimpls, tcState)
+
+                    // Compute the identity of the generated assembly based on attributes, options etc.
+                    // Some of this is duplicated from fsc.fs
+                    let ilAssemRef = 
+                        let publicKey = 
+                            try 
+                                let signingInfo = Driver.ValidateKeySigningAttributes (tcConfig, tcGlobals, topAttrs)
+                                match Driver.GetStrongNameSigner signingInfo with 
+                                | None -> None
+                                | Some s -> Some (PublicKey.KeyAsToken(s.PublicKey))
+                            with e -> 
+                                errorRecoveryNoRange e
+                                None
+                        let locale = TryFindFSharpStringAttribute tcGlobals (tcGlobals.FindSysAttrib  "System.Reflection.AssemblyCultureAttribute") topAttrs.assemblyAttrs
+                        let assemVerFromAttrib = 
+                            TryFindFSharpStringAttribute tcGlobals (tcGlobals.FindSysAttrib "System.Reflection.AssemblyVersionAttribute") topAttrs.assemblyAttrs 
+                            |> Option.bind  (fun v -> try Some (parseILVersion v) with _ -> None)
+                        let ver = 
+                            match assemVerFromAttrib with 
+                            | None -> tcConfig.version.GetVersionInfo(tcConfig.implicitIncludeDir)
+                            | Some v -> v
+                        ILAssemblyRef.Create(assemblyName, None, publicKey, false, Some ver, locale)
+                
+                    let tcAssemblyDataOpt = 
+                        try
+                          // Assemblies containing type provider components can not successfully be used via cross-assembly references.
+                          // We return 'None' for the assembly portion of the cross-assembly reference 
+                          let hasTypeProviderAssemblyAttrib = 
+                              topAttrs.assemblyAttrs |> List.exists (fun (Attrib(tcref, _, _, _, _, _, _)) -> tcref.CompiledRepresentationForNamedType.BasicQualifiedName = typeof<Microsoft.FSharp.Core.CompilerServices.TypeProviderAssemblyAttribute>.FullName)
+                          if tcState.CreatesGeneratedProvidedTypes || hasTypeProviderAssemblyAttrib then
+                            None
+                          else
+                            Some  (RawFSharpAssemblyDataBackedByLanguageService (tcConfig, tcGlobals, tcState, outfile, topAttrs, assemblyName, ilAssemRef) :> IRawFSharpAssemblyData)
+
+                        with e -> 
+                            errorRecoveryNoRange e
+                            None
+                    ilAssemRef, tcAssemblyDataOpt, Some tcAssemblyExpr
+                finally 
+                    tcState.Ccu.Deref.Contents <- oldContents
+            with e -> 
+                errorRecoveryNoRange e
+                mkSimpleAssemblyRef assemblyName, None, None
 
         let finalAccWithErrors = 
             { finalAcc with 
@@ -1561,9 +1575,9 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
     member this.IncrementUsageCount() = 
         assertNotDisposed() 
         System.Threading.Interlocked.Increment(&referenceCount) |> ignore
-        { new System.IDisposable with member x.Dispose() = this.DecrementUsageCount() }
+        { new System.IDisposable with member __.Dispose() = this.DecrementUsageCount() }
 
-    member this.DecrementUsageCount() = 
+    member __.DecrementUsageCount() = 
         assertNotDisposed()
         let currentValue =  System.Threading.Interlocked.Decrement(&referenceCount)
         if currentValue = 0 then 
@@ -1573,11 +1587,17 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
     member __.IsAlive = referenceCount > 0
 
     member __.TcConfig = tcConfig
+
     member __.FileParsed = fileParsed.Publish
+
     member __.BeforeFileChecked = beforeFileChecked.Publish
+
     member __.FileChecked = fileChecked.Publish
+
     member __.ProjectChecked = projectChecked.Publish
+
     member __.ImportedCcusInvalidated = importsInvalidated.Publish
+
     member __.AllDependenciesDeprecated = allDependencies
 
 #if !NO_EXTENSIONTYPING
@@ -1622,7 +1642,7 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
         | (*first file*) 0 -> IncrementalBuild.IsReady cache (Target(initialTcAccNode, None)) partialBuild 
         | _ -> IncrementalBuild.IsReady cache (Target(tcStatesNode, Some (slotOfFile-1))) partialBuild  
         
-    member builder.GetCheckResultsBeforeSlotInProject (ctok: CompilationThreadToken, slotOfFile) = 
+    member __.GetCheckResultsBeforeSlotInProject (ctok: CompilationThreadToken, slotOfFile) = 
       cancellable {
         let cache = TimeStampCache(defaultTimeStamp)
         let! result = 
@@ -1652,9 +1672,6 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
     member builder.GetCheckResultsAfterLastFileInProject (ctok: CompilationThreadToken) = 
         builder.GetCheckResultsBeforeSlotInProject(ctok, builder.GetSlotsCount()) 
 
-    member builder.DeduplicateParsedInputModuleNameInProject (input) = 
-        DeduplicateParsedInputModuleName moduleNamesDict input
-
     member __.GetCheckResultsAndImplementationsForProject(ctok: CompilationThreadToken) = 
       cancellable {
         let cache = TimeStampCache(defaultTimeStamp)
@@ -1861,10 +1878,11 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
 
         return builderOpt, diagnostics
       }
+
     static member KeepBuilderAlive (builderOpt: IncrementalBuilder option) = 
         match builderOpt with 
         | Some builder -> builder.IncrementUsageCount() 
         | None -> { new System.IDisposable with member __.Dispose() = () }
 
-    member builder.IsBeingKeptAliveApartFromCacheEntry = (referenceCount >= 2)
+    member __.IsBeingKeptAliveApartFromCacheEntry = (referenceCount >= 2)
 
diff --git a/src/fsharp/service/IncrementalBuild.fsi b/src/fsharp/service/IncrementalBuild.fsi
index b6b64a7ffd0..29c7a03a454 100755
--- a/src/fsharp/service/IncrementalBuild.fsi
+++ b/src/fsharp/service/IncrementalBuild.fsi
@@ -55,6 +55,9 @@ type internal PartialCheckResults =
       /// Represents open declarations
       TcOpenDeclarationsRev: OpenDeclaration[] list
 
+      /// Disambiguation table for module names
+      ModuleNamesDict: ModuleNamesDict
+
       TcDependencyFiles: string list
 
       /// Represents the collected attributes to apply to the module of assuembly generates
@@ -151,8 +154,6 @@ type internal IncrementalBuilder =
       // TODO: make this an Eventually (which can be scheduled) or an Async (which can be cancelled)
       member GetCheckResultsAndImplementationsForProject : CompilationThreadToken -> Cancellable<PartialCheckResults * IL.ILAssemblyRef * IRawFSharpAssemblyData option * TypedImplFile list option>
 
-      member DeduplicateParsedInputModuleNameInProject: Ast.ParsedInput -> Ast.ParsedInput
-
       /// Get the logical time stamp that is associated with the output of the project if it were gully built immediately
       member GetLogicalTimeStampForProject: TimeStampCache * CompilationThreadToken -> DateTime
 
diff --git a/src/fsharp/service/ServiceAssemblyContent.fs b/src/fsharp/service/ServiceAssemblyContent.fs
index b85396c26e7..663ed82a941 100644
--- a/src/fsharp/service/ServiceAssemblyContent.fs
+++ b/src/fsharp/service/ServiceAssemblyContent.fs
@@ -914,8 +914,9 @@ module ParsedInput =
         let rec walkImplFileInput (ParsedImplFileInput(modules = moduleOrNamespaceList)) = 
             List.iter (walkSynModuleOrNamespace []) moduleOrNamespaceList
 
-        and walkSynModuleOrNamespace (parent: LongIdent) (SynModuleOrNamespace(ident, _, isModule, decls, _, _, _, range)) =
+        and walkSynModuleOrNamespace (parent: LongIdent) (SynModuleOrNamespace(ident, _, kind, decls, _, _, _, range)) =
             if range.EndLine >= currentLine then
+                let isModule = kind.IsModule
                 match isModule, parent, ident with
                 | false, _, _ -> ns := Some (longIdentToIdents ident)
                 // top level module with "inlined" namespace like Ns1.Ns2.TopModule
diff --git a/src/fsharp/service/ServiceNavigation.fs b/src/fsharp/service/ServiceNavigation.fs
index cd7f43e2036..fd0453f88d9 100755
--- a/src/fsharp/service/ServiceNavigation.fs
+++ b/src/fsharp/service/ServiceNavigation.fs
@@ -273,7 +273,7 @@ module NavigationImpl =
         let items = 
             // Show base name for this module only if it's not the root one
             let singleTopLevel = (modules.Length = 1)
-            modules |> List.collect (fun (SynModuleOrNamespace(id, _isRec, isModule, decls, _, _, access, m)) ->
+            modules |> List.collect (fun (SynModuleOrNamespace(id, _isRec, kind, decls, _, _, access, m)) ->
                 let baseName = if (not singleTopLevel) then textOfLid id else ""
                 // Find let bindings (for the right dropdown)
                 let nested = processNestedDeclarations(decls)
@@ -286,7 +286,7 @@ module NavigationImpl =
                 | _ ->
                     let decl =
                         FSharpNavigationDeclarationItem.Create
-                            (textOfLid id, (if isModule then ModuleFileDecl else NamespaceDecl),
+                            (textOfLid id, (if kind.IsModule then ModuleFileDecl else NamespaceDecl),
                                 FSharpGlyph.Module, m, 
                                 unionRangesChecked (rangeOfDecls nested) (moduleRange (rangeOfLid id) other), 
                                 singleTopLevel, FSharpEnclosingEntityKind.Module, false, access), (addItemName(textOfLid id)), nested
@@ -413,7 +413,7 @@ module NavigationImpl =
         let items = 
             // Show base name for this module only if it's not the root one
             let singleTopLevel = (modules.Length = 1)
-            modules |> List.collect (fun (SynModuleOrNamespaceSig(id, _isRec, isModule, decls, _, _, access, m)) ->
+            modules |> List.collect (fun (SynModuleOrNamespaceSig(id, _isRec, kind, decls, _, _, access, m)) ->
                 let baseName = if (not singleTopLevel) then textOfLid id else ""
                 // Find let bindings (for the right dropdown)
                 let nested = processNestedSigDeclarations(decls)
@@ -423,7 +423,7 @@ module NavigationImpl =
                 // Create explicitly - it can be 'single top level' thing that is hidden
                 let decl =
                     FSharpNavigationDeclarationItem.Create
-                        (textOfLid id, (if isModule then ModuleFileDecl else NamespaceDecl),
+                        (textOfLid id, (if kind.IsModule then ModuleFileDecl else NamespaceDecl),
                             FSharpGlyph.Module, m, 
                             unionRangesChecked (rangeOfDecls nested) (moduleRange (rangeOfLid id) other), 
                             singleTopLevel, FSharpEnclosingEntityKind.Module, false, access), (addItemName(textOfLid id)), nested
@@ -577,7 +577,8 @@ module NavigateTo =
             for item in moduleOrNamespaceList do
                 walkSynModuleOrNamespaceSig item { Type = ContainerType.File; Name = fileName }
     
-        and walkSynModuleOrNamespaceSig (SynModuleOrNamespaceSig(lid, _, isModule, decls, _, _, _, _)) container = 
+        and walkSynModuleOrNamespaceSig (SynModuleOrNamespaceSig(lid, _, kind, decls, _, _, _, _)) container =
+            let isModule = kind.IsModule
             if isModule then
                 addModule lid true container
             let container = 
@@ -634,7 +635,8 @@ module NavigateTo =
             for item in moduleOrNamespaceList do
                 walkSynModuleOrNamespace item container
     
-        and walkSynModuleOrNamespace(SynModuleOrNamespace(lid, _, isModule, decls, _, _, _, _)) container =
+        and walkSynModuleOrNamespace(SynModuleOrNamespace(lid, _, kind, decls, _, _, _, _)) container =
+            let isModule = kind.IsModule
             if isModule then
                 addModule lid false container
             let container = 
diff --git a/src/fsharp/service/ServiceParseTreeWalk.fs b/src/fsharp/service/ServiceParseTreeWalk.fs
index f84f84bb993..da673eb4083 100755
--- a/src/fsharp/service/ServiceParseTreeWalk.fs
+++ b/src/fsharp/service/ServiceParseTreeWalk.fs
@@ -458,9 +458,12 @@ module public AstTraversal =
                      dive synExpr2 synExpr2.Range traverseSynExpr
                      dive synExpr3 synExpr3.Range traverseSynExpr]
                     |> pick expr
-                | SynExpr.TypeTest(synExpr, _synType, _range) -> traverseSynExpr synExpr
-                | SynExpr.Upcast(synExpr, _synType, _range) -> traverseSynExpr synExpr
-                | SynExpr.Downcast(synExpr, _synType, _range) -> traverseSynExpr synExpr
+                | SynExpr.TypeTest(synExpr, synType, _range)
+                | SynExpr.Upcast(synExpr, synType, _range)
+                | SynExpr.Downcast(synExpr, synType, _range) ->
+                    [dive synExpr synExpr.Range traverseSynExpr
+                     dive synType synType.Range traverseSynType]
+                    |> pick expr
                 | SynExpr.InferredUpcast(synExpr, _range) -> traverseSynExpr synExpr
                 | SynExpr.InferredDowncast(synExpr, _range) -> traverseSynExpr synExpr
                 | SynExpr.Null(_range) -> None
diff --git a/src/fsharp/service/ServiceStructure.fs b/src/fsharp/service/ServiceStructure.fs
index f225c87b6d0..a89afd44c54 100644
--- a/src/fsharp/service/ServiceStructure.fs
+++ b/src/fsharp/service/ServiceStructure.fs
@@ -610,14 +610,14 @@ module Structure =
                 parseAttributes attrs
             | _ -> ()
 
-        let parseModuleOrNamespace isScript (SynModuleOrNamespace (longId,_,isModule,decls,_,attribs,_,r)) =
+        let parseModuleOrNamespace (SynModuleOrNamespace (longId,_,kind,decls,_,attribs,_,r)) =
             parseAttributes attribs
             let idRange = longIdentRange longId
             let fullrange = Range.startToEnd idRange r  
             let collapse = Range.endToEnd idRange r 
         
             // do not return range for top level implicit module in scripts
-            if isModule && not isScript then
+            if kind = NamedModule then
                 rcheck Scope.Module Collapse.Below fullrange collapse
 
             collectHashDirectives decls
@@ -833,14 +833,14 @@ module Structure =
                 List.iter parseModuleSigDeclaration decls
             | _ -> ()
 
-        let parseModuleOrNamespaceSigs (SynModuleOrNamespaceSig(longId,_,isModule,decls,_,attribs,_,r)) =
+        let parseModuleOrNamespaceSigs (SynModuleOrNamespaceSig(longId,_,kind,decls,_,attribs,_,r)) =
             parseAttributes attribs
             let rangeEnd = lastModuleSigDeclRangeElse r decls
             let idrange = longIdentRange longId
             let fullrange = Range.startToEnd idrange rangeEnd
             let collapse = Range.endToEnd idrange rangeEnd
             
-            if isModule then
+            if kind.IsModule then
                 rcheck Scope.Module Collapse.Below fullrange collapse
 
             collectSigHashDirectives decls
@@ -848,8 +848,8 @@ module Structure =
             List.iter parseModuleSigDeclaration decls
 
         match parsedInput with
-        | ParsedInput.ImplFile (ParsedImplFileInput (modules = modules; isScript = isScript)) ->
-            modules |> List.iter (parseModuleOrNamespace isScript)
+        | ParsedInput.ImplFile (ParsedImplFileInput (modules = modules)) ->
+            modules |> List.iter parseModuleOrNamespace
             getCommentRanges sourceLines
         | ParsedInput.SigFile (ParsedSigFileInput (modules = moduleSigs)) ->
             List.iter parseModuleOrNamespaceSigs moduleSigs
diff --git a/src/fsharp/service/service.fs b/src/fsharp/service/service.fs
index 3545293e44e..bc176102748 100644
--- a/src/fsharp/service/service.fs
+++ b/src/fsharp/service/service.fs
@@ -1614,6 +1614,7 @@ module internal Parser =
            tcGlobals: TcGlobals,
            tcImports: TcImports,
            tcState: TcState,
+           moduleNamesDict: ModuleNamesDict,
            loadClosure: LoadClosure option,
            // These are the errors and warnings seen by the background compiler for the entire antecedent 
            backgroundDiagnostics: (PhasedDiagnostic * FSharpErrorSeverity)[],    
@@ -1718,6 +1719,9 @@ module internal Parser =
                     async {
                         try
                             let checkForErrors() = (parseResults.ParseHadErrors || errHandler.ErrorCount > 0)
+
+                            let parsedMainInput, _moduleNamesDict = DeduplicateParsedInputModuleName moduleNamesDict parsedMainInput
+
                             // Typecheck is potentially a long running operation. We chop it up here with an Eventually continuation and, at each slice, give a chance
                             // for the client to claim the result as obsolete and have the typecheck abort.
                             
@@ -1904,7 +1908,8 @@ type FSharpCheckProjectResults(projectFileName:string, tcConfigOption, keepAssem
         let cenv = SymbolEnv(tcGlobals, thisCcu, Some ccuSig, tcImports)
 
         [| for r in tcSymbolUses do
-             for symbolUse in r.AllUsesOfSymbols do
+             for symbolUseChunk in r.AllUsesOfSymbols do
+                for symbolUse in symbolUseChunk do
                 if symbolUse.ItemOccurence <> ItemOccurence.RelatedText then
                   let symbol = FSharpSymbol.Create(cenv, symbolUse.Item)
                   yield FSharpSymbolUse(tcGlobals, symbolUse.DisplayEnv, symbol, symbolUse.ItemOccurence, symbolUse.Range) |]
@@ -2098,7 +2103,8 @@ type FSharpCheckFileResults(filename: string, errors: FSharpErrorInfo[], scopeOp
             (fun () -> [| |])
             (fun scope ->
                 let cenv = scope.SymbolEnv
-                [| for symbolUse in scope.ScopeSymbolUses.AllUsesOfSymbols do
+                [| for symbolUseChunk in scope.ScopeSymbolUses.AllUsesOfSymbols do
+                    for symbolUse in symbolUseChunk do
                     if symbolUse.ItemOccurence <> ItemOccurence.RelatedText then
                         let symbol = FSharpSymbol.Create(cenv, symbolUse.Item)
                         yield FSharpSymbolUse(scope.TcGlobals, symbolUse.DisplayEnv, symbol, symbolUse.ItemOccurence, symbolUse.Range) |])
@@ -2596,7 +2602,7 @@ type BackgroundCompiler(legacyReferenceResolver, projectCacheSize, keepAssemblyC
                                 let loadClosure = scriptClosureCacheLock.AcquireLock (fun ltok -> scriptClosureCache.TryGet (ltok, options))
                                 let! tcErrors, tcFileResult = 
                                     Parser.CheckOneFile(parseResults, sourceText, fileName, options.ProjectFileName, tcPrior.TcConfig, tcPrior.TcGlobals, tcPrior.TcImports, 
-                                                        tcPrior.TcState, loadClosure, tcPrior.TcErrors, reactorOps, (fun () -> builder.IsAlive), textSnapshotInfo, userOpName)
+                                                        tcPrior.TcState, tcPrior.ModuleNamesDict, loadClosure, tcPrior.TcErrors, reactorOps, (fun () -> builder.IsAlive), textSnapshotInfo, userOpName)
                                 let parsingOptions = FSharpParsingOptions.FromTcConfig(tcPrior.TcConfig, Array.ofList builder.SourceFiles, options.UseScriptResolutionRules)
                                 let checkAnswer = MakeCheckFileAnswer(fileName, tcFileResult, options, builder, Array.ofList tcPrior.TcDependencyFiles, creationErrors, parseResults.Errors, tcErrors)
                                 bc.RecordTypeCheckFileInProjectResults(fileName, options, parsingOptions, parseResults, fileVersion, tcPrior.TimeStamp, Some checkAnswer, sourceText.GetHashCode())
@@ -2677,9 +2683,7 @@ type BackgroundCompiler(legacyReferenceResolver, projectCacheSize, keepAssemblyC
                     | _ ->
                         Trace.TraceInformation("FCS: {0}.{1} ({2})", userOpName, "CheckFileInProject.CacheMiss", filename)
                         let! tcPrior = execWithReactorAsync <| fun ctok -> builder.GetCheckResultsBeforeFileInProject (ctok, filename)
-                        let parseTreeOpt = parseResults.ParseTree |> Option.map builder.DeduplicateParsedInputModuleNameInProject
-                        let parseResultsAterDeDuplication = FSharpParseFileResults(parseResults.Errors, parseTreeOpt, parseResults.ParseHadErrors, parseResults.DependencyFiles)
-                        let! checkAnswer = bc.CheckOneFileImpl(parseResultsAterDeDuplication, sourceText, filename, options, textSnapshotInfo, fileVersion, builder, tcPrior, creationErrors, userOpName)
+                        let! checkAnswer = bc.CheckOneFileImpl(parseResults, sourceText, filename, options, textSnapshotInfo, fileVersion, builder, tcPrior, creationErrors, userOpName)
                         return checkAnswer
             finally 
                 bc.ImplicitlyStartCheckProjectInBackground(options, userOpName)
@@ -2722,7 +2726,6 @@ type BackgroundCompiler(legacyReferenceResolver, projectCacheSize, keepAssemblyC
                         // Do the parsing.
                         let parsingOptions = FSharpParsingOptions.FromTcConfig(builder.TcConfig, Array.ofList (builder.SourceFiles), options.UseScriptResolutionRules)
                         let parseErrors, parseTreeOpt, anyErrors = Parser.parseFile (sourceText, filename, parsingOptions, userOpName)
-                        let parseTreeOpt = parseTreeOpt |> Option.map builder.DeduplicateParsedInputModuleNameInProject
                         let parseResults = FSharpParseFileResults(parseErrors, parseTreeOpt, anyErrors, builder.AllDependenciesDeprecated)
                         let! checkResults = bc.CheckOneFileImpl(parseResults, sourceText, filename, options, textSnapshotInfo, fileVersion, builder, tcPrior, creationErrors, userOpName)
 
@@ -3322,7 +3325,7 @@ type FsiInteractiveChecker(legacyReferenceResolver, reactorOps: IReactorOperatio
                 CompileOptions.ParseCompilerOptions (ignore, fsiCompilerOptions, [ ])
 
             let loadClosure = LoadClosure.ComputeClosureOfScriptText(ctok, legacyReferenceResolver, defaultFSharpBinariesDir, filename, sourceText, CodeContext.Editing, tcConfig.useSimpleResolution, tcConfig.useFsiAuxLib, new Lexhelp.LexResourceManager(), applyCompilerOptions, assumeDotNetFramework, tryGetMetadataSnapshot=(fun _ -> None), reduceMemoryUsage=reduceMemoryUsage)
-            let! tcErrors, tcFileResult =  Parser.CheckOneFile(parseResults, sourceText, filename, "project", tcConfig, tcGlobals, tcImports,  tcState, Some loadClosure, backgroundDiagnostics, reactorOps, (fun () -> true), None, userOpName)
+            let! tcErrors, tcFileResult =  Parser.CheckOneFile(parseResults, sourceText, filename, "project", tcConfig, tcGlobals, tcImports,  tcState, Map.empty, Some loadClosure, backgroundDiagnostics, reactorOps, (fun () -> true), None, userOpName)
 
             return
                 match tcFileResult with 
diff --git a/src/utils/EditDistance.fs b/src/utils/EditDistance.fs
index 6beac0c408f..503662400ff 100644
--- a/src/utils/EditDistance.fs
+++ b/src/utils/EditDistance.fs
@@ -23,33 +23,45 @@ let jaro (s1: string) (s2: string) =
     let matchRadius = 
         let minLen = Math.Min(s1.Length, s2.Length)
         minLen / 2 + minLen % 2
-    
-    // An inner function which recursively finds the number  
-    // of matched characters within the radius.
-    let commonChars (chars1: string) (chars2: string) =
-        let result = ResizeArray(chars1.Length)
-        for i = 0 to chars1.Length - 1 do
-            let c = chars1.[i]
-            if existsInWin c chars2 i matchRadius then 
-                result.Add c
-        result
-    
-    // The sets of common characters and their lengths as floats 
-    let c1 = commonChars s1 s2
-    let c2 = commonChars s2 s1
-    let c1length = float c1.Count
-    let c2length = float c2.Count
-        
+
+    let rec nextChar (s1:string) (s2:string) i c =
+        if i < s1.Length then
+            let c = s1.[i]
+            if not (existsInWin c s2 i matchRadius) then
+                nextChar s1 s2 (i + 1) c
+            else
+                struct (i, c)
+        else
+            struct (i, c)
+
+    // The sets of common characters and their lengths as floats         
     // The number of transpositions within the sets of common characters.
-    let transpositions =
-        let mutable mismatches = 0.0
-        for i = 0 to (Math.Min(c1.Count, c2.Count)) - 1 do
-            if c1.[i] <> c2.[i] then 
-                mismatches <- mismatches + 1.0
-                        
-        // If one common string is longer than the other
-        // each additional char counts as half a transposition
-        (mismatches + abs (c1length - c2length)) / 2.0
+    let struct (transpositions, c1length, c2length) =
+        let rec loop i j mismatches c1length c2length =
+            if i < s1.Length && j < s2.Length then
+                let struct (ti, ci) = nextChar s1 s2 i ' '
+                let struct (tj, cj) = nextChar s2 s1 j ' '
+                if ci <> cj then
+                    loop (ti + 1) (tj + 1) (mismatches + 1) (c1length + 1) (c2length + 1)
+                else
+                    loop (ti + 1) (tj + 1) mismatches (c1length + 1) (c2length + 1)
+            else struct (i, j, mismatches, c1length, c2length)
+
+        let struct (i, j, mismatches, c1length, c2length) = loop 0 0 0 0 0
+
+        let rec loop (s1:string) (s2:string) i length =
+            if i < s1.Length - 1 then
+                let c = s1.[i]
+                if existsInWin c s2 i matchRadius then 
+                    loop s1 s2 (i + 1) (length + 1)
+                else
+                    loop s1 s2 (i + 1) length
+            else
+                length
+        let c1length = loop s1 s2 i c1length |> float
+        let c2length = loop s2 s1 j c2length |> float
+
+        struct ((float mismatches + abs (c1length - c2length)) / 2.0, c1length, c2length)
     
     let tLength = Math.Max(c1length, c2length)
     
diff --git a/tests/.gitignore b/tests/.gitignore
index 2de72583ada..bf970a32fde 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -1,6 +1,5 @@
 FSharp_*
 net40-fsharpqa-suite-*
 CoreUnit_*
-TestResults
 *.il
 dont.run.peverify
\ No newline at end of file
diff --git a/tests/EndToEndBuildTests/BasicProvider/TestBasicProvider.cmd b/tests/EndToEndBuildTests/BasicProvider/TestBasicProvider.cmd
index 7d8475c39c3..56af32e144b 100644
--- a/tests/EndToEndBuildTests/BasicProvider/TestBasicProvider.cmd
+++ b/tests/EndToEndBuildTests/BasicProvider/TestBasicProvider.cmd
@@ -16,17 +16,18 @@ rem Test it with both desktop and coreclr compilers
 rem
 
 if not '%NUGET_PACKAGES%' == '' rd %NUGET_PACKAGES%\BasicProvider /s /q
+taskkill /F /IM dotnet.exe
 
-@echo %__scriptpath%..\..\..\tools\dotnet20\dotnet.exe pack BasicProvider\BasicProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=net40
-%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe pack BasicProvider\BasicProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=net40
+@echo %__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe pack BasicProvider\BasicProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=net40 -nr=false
+%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe pack BasicProvider\BasicProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=net40 -nr=false
 @if ERRORLEVEL 1 echo Error: TestBasicProvider failed  && goto :failure
 
-@echo %__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40
-%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40
+@echo %__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40 -nr=false
+%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40 -nr=false
 @if ERRORLEVEL 1 echo Error: TestBasicProvider failed  && goto :failure
 
-@echo %__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr
-%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr
+@echo %__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr -nr=false
+%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr -nr=false
 @if ERRORLEVEL 1 echo Error: TestBasicProvider failed  && goto :failure
 
 rem
@@ -35,16 +36,16 @@ rem Test it with both desktop and coreclr compilers
 rem
 if not '%NUGET_PACKAGES%' == '' rd %NUGET_PACKAGES%\BasicProvider /s /q
 
-@echo %__scriptpath%..\..\..\tools\dotnet20\dotnet.exe pack BasicProvider\BasicProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=coreclr
-%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe pack BasicProvider\BasicProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=coreclr
+@echo %__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe pack BasicProvider\BasicProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=coreclr -nr=false
+%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe pack BasicProvider\BasicProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=coreclr -nr=false
 @if ERRORLEVEL 1 echo Error: TestBasicProvider failed  && goto :failure
 
-@echo%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40
-%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40
+@echo%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40 -nr=false
+%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40 -nr=false
 @if ERRORLEVEL 1 echo Error: TestBasicProvider failed  && goto :failure
 
-@echo %__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr
-%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr
+@echo %__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr -nr=false
+%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test BasicProvider.Tests\BasicProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr -nr=false
 @if ERRORLEVEL 1 echo Error: TestBasicProvider failed  && goto :failure
 
 :success
diff --git a/tests/EndToEndBuildTests/ComboProvider/TestComboProvider.cmd b/tests/EndToEndBuildTests/ComboProvider/TestComboProvider.cmd
index ccd8c4d2e3b..74035032e29 100644
--- a/tests/EndToEndBuildTests/ComboProvider/TestComboProvider.cmd
+++ b/tests/EndToEndBuildTests/ComboProvider/TestComboProvider.cmd
@@ -15,17 +15,18 @@ rem Test it with both desktop and coreclr compilers
 rem
 
 if not '%NUGET_PACKAGES%' == '' rd %NUGET_PACKAGES%\ComboProvider /s /q
+taskkill /F /IM dotnet.exe
 
-@echo %__scriptpath%..\..\..\tools\dotnet20\dotnet.exe pack ComboProvider\ComboProvider\ComboProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=net40
-%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe pack ComboProvider\ComboProvider\ComboProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=net40
+@echo %__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe pack ComboProvider\ComboProvider\ComboProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=net40 -nr=false
+%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe pack ComboProvider\ComboProvider\ComboProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=net40 -nr=false
 @if ERRORLEVEL 1 echo Error: ComboProvider failed  && goto :failure
 
-@echo %__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40
-%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40
+@echo %__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40 -nr=false
+%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40 -nr=false
 @if ERRORLEVEL 1 echo Error: ComboProvider failed  && goto :failure
 
-@echo %__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr
-%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr
+@echo %__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr -nr=false
+%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr -nr=false
 @if ERRORLEVEL 1 echo Error: ComboProviderProvider failed  && goto :failure
 
 rem
@@ -34,16 +35,16 @@ rem Test it with both desktop and coreclr compilers
 rem
 if not '%NUGET_PACKAGES%' == '' rd %NUGET_PACKAGES%\ComboProvider /s /q
 
-@echo %__scriptpath%..\..\..\tools\dotnet20\dotnet.exe pack ComboProvider\ComboProvider\ComboProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=coreclr
-%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe pack ComboProvider\ComboProvider\ComboProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=coreclr
+@echo %__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe pack ComboProvider\ComboProvider\ComboProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=coreclr -nr=false
+%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe pack ComboProvider\ComboProvider\ComboProvider.fsproj -o %~dp0artifacts -c release -v minimal -p:FSharpTestCompilerVersion=coreclr -nr=false
 @if ERRORLEVEL 1 echo Error: ComboProviderProvider failed  && goto :failure
 
-@echo%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40
-%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40
+@echo%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40 -nr=false
+%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=net461 -p:FSharpTestCompilerVersion=net40 -nr=false
 @if ERRORLEVEL 1 echo Error: TestBasicProvider failed  && goto :failure
 
-@echo %__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr
-%__scriptpath%..\..\..\tools\dotnet20\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr
+@echo %__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr -nr=false
+%__scriptpath%..\..\..\artifacts\toolset\dotnet\dotnet.exe test ComboProvider\ComboProvider.Tests\ComboProvider.Tests.fsproj -c release -v minimal -p:TestTargetFramework=netcoreapp2.0 -p:FSharpTestCompilerVersion=coreclr -nr=false
 @if ERRORLEVEL 1 echo Error: ComboProvider failed  && goto :failure
 
 :success
diff --git a/tests/FSharp.Directory.Build.props b/tests/FSharp.Directory.Build.props
index 19257808542..bb8eac309b1 100644
--- a/tests/FSharp.Directory.Build.props
+++ b/tests/FSharp.Directory.Build.props
@@ -1,9 +1,3 @@
 <Project>
-
   <Import Project="$([MSBuild]::GetPathOfFileAbove('FSharp.Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
-
-  <PropertyGroup>
-    <DisableOutputPathCopying></DisableOutputPathCopying>
-  </PropertyGroup>
-
 </Project>
diff --git a/tests/fsharp/SDKTests/AllSdkTargetsTests.proj b/tests/fsharp/SDKTests/AllSdkTargetsTests.proj
index 857e3efd636..9da3a21fea1 100644
--- a/tests/fsharp/SDKTests/AllSdkTargetsTests.proj
+++ b/tests/fsharp/SDKTests/AllSdkTargetsTests.proj
@@ -1,7 +1,7 @@
 <Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 
   <PropertyGroup>
-    <Configuration Condition="'$(Configuration)' == ''">release</Configuration>
+    <Configuration Condition="'$(Configuration)' == ''">Release</Configuration>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/tests/fsharp/SDKTests/tests/Test.props b/tests/fsharp/SDKTests/tests/Test.props
index fdfc314758e..8d29b210bfb 100644
--- a/tests/fsharp/SDKTests/tests/Test.props
+++ b/tests/fsharp/SDKTests/tests/Test.props
@@ -2,18 +2,18 @@
 
   <PropertyGroup>
 
-    <TargetFramework Condition="'$(TargetFramework)' == ''">net46</TargetFramework>
-    <_TargetFrameworkVersionWithoutV Condition="'$(_TargetFrameworkVersionWithoutV)' == ''">4.6</_TargetFrameworkVersionWithoutV>
+    <TargetFramework Condition="'$(TargetFramework)' == ''">net472</TargetFramework>
+    <_TargetFrameworkVersionWithoutV Condition="'$(_TargetFrameworkVersionWithoutV)' == ''">4.7.2</_TargetFrameworkVersionWithoutV>
     <TargetFrameworkIdentifier Condition="'$(TargetFrameworkIdentifier)' == ''">.NETFramework</TargetFrameworkIdentifier>
 
-    <Configuration Condition="'$(Configuration)' == ''">release</Configuration>
-    <BinariesDirectory>$(MSBuildThisFileDirectory)..\..\..\..\$(Configuration)\net40\bin</BinariesDirectory>
+    <Configuration Condition="'$(Configuration)' == ''">Release</Configuration>
+    <TargetsDirectory>$(MSBuildThisFileDirectory)..\..\..\..\artifacts\bin\FSharp.Build\$(Configuration)\net472</TargetsDirectory>
 
     <!-- these properties don't really matter, but they're necessary to make MSBuild happy -->
     <Platform Condition="'$(Platform)' == ''">AnyCPU</Platform>
     <OutputPath>$(MSBuildThisFileDirectory)</OutputPath>
   </PropertyGroup>
 
-  <Import Project="$(BinariesDirectory)\Microsoft.FSharp.NetSdk.props" />
+  <Import Project="$(TargetsDirectory)\Microsoft.FSharp.NetSdk.props" />
 
 </Project>
diff --git a/tests/fsharp/SDKTests/tests/Test.targets b/tests/fsharp/SDKTests/tests/Test.targets
index 5526c118403..6f1638051d8 100644
--- a/tests/fsharp/SDKTests/tests/Test.targets
+++ b/tests/fsharp/SDKTests/tests/Test.targets
@@ -1,6 +1,6 @@
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 
-  <Import Project="$(BinariesDirectory)\Microsoft.FSharp.NetSdk.targets" />
+  <Import Project="$(TargetsDirectory)\Microsoft.FSharp.NetSdk.targets" />
 
   <Target Name="Test">
 
diff --git a/tests/fsharp/Test.Directory.Build.props b/tests/fsharp/Test.Directory.Build.props
deleted file mode 100644
index 6603d10e659..00000000000
--- a/tests/fsharp/Test.Directory.Build.props
+++ /dev/null
@@ -1,8 +0,0 @@
-<Project>
-  <PropertyGroup>
-    <FSharpTargetsPath>$(CompilerTestPath)\Microsoft.FSharp.Targets</FSharpTargetsPath>
-    <FSharpPropsShim>$(CompilerTestPath)\Microsoft.FSharp.NetSdk.props</FSharpPropsShim>
-    <FSharpTargetsShim>$(CompilerTestPath)\Microsoft.FSharp.NetSdk.targets</FSharpTargetsShim>
-    <FSharpOverridesTargetsShim>$(CompilerTestPath)\Microsoft.FSharp.Overrides.NetSdk.targets</FSharpOverridesTargetsShim>
-  </PropertyGroup>
-</Project>
diff --git a/tests/fsharp/single-test.fs b/tests/fsharp/single-test.fs
index 537fa6aa499..54915dc1ec1 100644
--- a/tests/fsharp/single-test.fs
+++ b/tests/fsharp/single-test.fs
@@ -62,10 +62,10 @@ type ProjectConfiguration = {
 
 let replaceTokens tag (replacement:string) (template:string) = template.Replace(tag, replacement)
 
-let generateProps testCompilerVersion=
+let generateProps testCompilerVersion =
     let template = @"<Project>
   <PropertyGroup>
-    <Configuration Condition=""'$(Configuration)' == ''"">release</Configuration>
+    <Configuration Condition=""'$(Configuration)' == ''"">Release</Configuration>
     <FSharpTestCompilerVersion>$(TESTCOMPILERVERSION)</FSharpTestCompilerVersion>
   </PropertyGroup>
   <Import Project=""$([MSBuild]::GetPathOfFileAbove('FSharp.Directory.Build.props', '$(PROJECTDIRECTORY)'))"" />
@@ -96,13 +96,13 @@ let generateProjectArtifacts (pc:ProjectConfiguration) targetFramework =
             let condition = if addCondition then " Condition=\"Exists('" + fileName + "')\"" else ""
             match compileItem with
             | CompileItem.Compile ->
-                "\n    <Compile Include ='" + fileName + "'" + condition + " />"
+                "\n    <Compile Include='" + fileName + "'" + condition + " />"
             | CompileItem.Reference ->
-                "\n    <Reference Include ='" + fileName + "'" + condition + " />"
+                "\n    <Reference Include='" + fileName + "'" + condition + " />"
             | CompileItem.UseSource ->
-                "\n    <UseSource Include ='" + fileName + "'" + condition + " />"
+                "\n    <UseSource Include='" + fileName + "'" + condition + " />"
             | CompileItem.LoadSource ->
-                "\n    <LoadSource Include ='" + fileName + "'" + condition + " />"
+                "\n    <LoadSource Include='" + fileName + "'" + condition + " />"
 
         sources
         |> List.map(fun src -> computeInclude src)
@@ -221,7 +221,7 @@ let singleTestBuildAndRunCore cfg copyFiles p =
                     let projectBody = generateProjectArtifacts pc targetFramework 
                     emitFile projectFileName projectBody
                     use testOkFile = new FileGuard(Path.Combine(directory, "test.ok"))
-                    exec { cfg with Directory = directory }  cfg.DotNet20Exe (sprintf "run -f %s" targetFramework)
+                    exec { cfg with Directory = directory }  cfg.DotNetExe (sprintf "run -f %s" targetFramework)
                     testOkFile.CheckExists()
                 executeFsc compilerType targetFramework
             else
@@ -231,7 +231,7 @@ let singleTestBuildAndRunCore cfg copyFiles p =
                     let projectBody = generateProjectArtifacts pc targetFramework 
                     emitFile projectFileName projectBody
                     use testOkFile = new FileGuard(Path.Combine(directory, "test.ok"))
-                    exec { cfg with Directory = directory }  cfg.DotNet20Exe "build /t:RunFSharpScript"
+                    exec { cfg with Directory = directory }  cfg.DotNetExe "build /t:RunFSharpScript"
                     testOkFile.CheckExists()
                 executeFsi compilerType targetFramework
                 result <- true
diff --git a/tests/fsharp/test-framework.fs b/tests/fsharp/test-framework.fs
index df2570d4d8b..bb4b134f8d0 100644
--- a/tests/fsharp/test-framework.fs
+++ b/tests/fsharp/test-framework.fs
@@ -122,19 +122,19 @@ type TestConfig =
       BUILD_CONFIG : string
       FSC : string
       fsc_flags : string
-      BinPath : string
       FSCOREDLLPATH : string
       FSI : string
 #if !FSHARP_SUITE_DRIVES_CORECLR_TESTS
       FSIANYCPU : string
 #endif
       FSI_FOR_SCRIPTS : string
+      FSharpBuild : string
+      FSharpCompilerInteractiveSettings : string
       fsi_flags : string
       ILDASM : string
       PEVERIFY : string
       Directory: string 
       DotNetExe: string
-      DotNet20Exe: string
       DefaultPlatform: string}
 
 
@@ -157,11 +157,21 @@ let config configurationName envVars =
     let SCRIPT_ROOT = __SOURCE_DIRECTORY__
     let packagesDir = Environment.GetEnvironmentVariable("USERPROFILE") ++ ".nuget" ++ "packages"
 #if NET472
-    let architecture = "net40"
+    let fscArchitecture = "net472"
+    let fsiArchitecture = "net472"
+    let fsharpCoreArchitecture = "net45"
+    let fsharpBuildArchitecture = "net472"
+    let fsharpCompilerInteractiveSettingsArchitecture = "net472"
 #else
-    let architecture = "coreclr"
+    let fscArchitecture = "netcoreapp2.1"
+    let fsiArchitecture = "netcoreapp2.1"
+    let fsharpCoreArchitecture = "netstandard1.6"
+    let fsharpBuildArchitecture = "netstandard2.0"
+    let fsharpCompilerInteractiveSettingsArchitecture = "netstandard1.6"
 #endif
-    let BINPATH = SCRIPT_ROOT ++ ".." ++ ".." ++ configurationName ++ architecture ++ "bin"
+    let repoRoot = SCRIPT_ROOT ++ ".." ++ ".."
+    let artifactsPath = repoRoot ++ "artifacts"
+    let artifactsBinPath = artifactsPath ++ "bin"
     let csc_flags = "/nologo" 
     let fsc_flags = "-r:System.Core.dll --nowarn:20 --define:COMPILED"
     let fsi_flags = "-r:System.Core.dll --nowarn:20 --define:INTERACTIVE --maxerrors:1 --abortonerror"
@@ -170,20 +180,20 @@ let config configurationName envVars =
     let CSC = requireFile (packagesDir ++ "Microsoft.Net.Compilers" ++ "2.7.0" ++ "tools" ++ "csc.exe")
     let ILDASM = requireFile (packagesDir ++ ("runtime.win-" + architectureMoniker + ".Microsoft.NETCore.ILDAsm") ++ "2.0.3" ++ "runtimes" ++ ("win-" + architectureMoniker) ++ "native" ++ "ildasm.exe")
     let coreclrdll = requireFile (packagesDir ++ ("runtime.win-" + architectureMoniker + ".Microsoft.NETCore.Runtime.CoreCLR") ++ "2.0.3" ++ "runtimes" ++ ("win-" + architectureMoniker) ++ "native" ++ "coreclr.dll")
-    let PEVERIFY = requireFile (SCRIPT_ROOT ++ ".." ++ "fsharpqa" ++ "testenv" ++ "src" ++ "PEVerify" ++ "bin" ++ configurationName ++ "net472" ++ "PEVerify.exe")
-    let FSI_FOR_SCRIPTS = BINPATH ++ "fsi.exe"
-    let toolsDir = SCRIPT_ROOT ++ ".." ++ ".." ++ "Tools"
-    let dotNetExe = toolsDir ++ "dotnetcli" ++ "dotnet.exe"
-    let dotNet20Exe = toolsDir ++ "dotnet20" ++ "dotnet.exe"
+    let PEVERIFY = requireFile (artifactsBinPath ++ "PEVerify" ++ configurationName ++ "net472" ++ "PEVerify.exe")
+    let FSI_FOR_SCRIPTS = artifactsBinPath ++ "fsi" ++ configurationName ++ fsiArchitecture ++ "fsi.exe"
+    let FSharpBuild = requireFile (artifactsBinPath ++ "FSharp.Build" ++ configurationName ++ fsharpBuildArchitecture ++ "FSharp.Build.dll")
+    let FSharpCompilerInteractiveSettings = requireFile (artifactsBinPath ++ "FSharp.Compiler.Interactive.Settings" ++ configurationName ++ fsharpCompilerInteractiveSettingsArchitecture ++ "FSharp.Compiler.Interactive.Settings.dll")
+    let dotNetExe = artifactsPath ++ "toolset" ++ "dotnet" ++ "dotnet.exe"
     // ildasm requires coreclr.dll to run which has already been restored to the packages directory
     File.Copy(coreclrdll, Path.GetDirectoryName(ILDASM) ++ "coreclr.dll", overwrite=true)
 
-    let FSI = requireFile (BINPATH ++ "fsi.exe")
+    let FSI = requireFile (FSI_FOR_SCRIPTS)
 #if !FSHARP_SUITE_DRIVES_CORECLR_TESTS
-    let FSIANYCPU = requireFile (BINPATH ++ "fsiAnyCpu.exe")
+    let FSIANYCPU = requireFile (artifactsBinPath ++ "fsiAnyCpu" ++ configurationName ++ "net472" ++ "fsiAnyCpu.exe")
 #endif
-    let FSC = requireFile (BINPATH ++ "fsc.exe")
-    let FSCOREDLLPATH = requireFile (BINPATH ++ "FSharp.Core.dll")
+    let FSC = requireFile (artifactsBinPath ++ "fsc" ++ configurationName ++ fscArchitecture ++ "fsc.exe")
+    let FSCOREDLLPATH = requireFile (artifactsBinPath ++ "FSharp.Core" ++ configurationName ++ fsharpCoreArchitecture ++ "FSharp.Core.dll")
 
     let defaultPlatform = 
         match Is64BitOperatingSystem with 
@@ -193,7 +203,6 @@ let config configurationName envVars =
         | false -> "win7-x86"
 
     { EnvironmentVariables = envVars
-      BinPath = BINPATH |> Commands.pathAddBackslash
       FSCOREDLLPATH = FSCOREDLLPATH
       ILDASM = ILDASM
       PEVERIFY = PEVERIFY
@@ -205,12 +214,13 @@ let config configurationName envVars =
       FSIANYCPU = FSIANYCPU
 #endif
       FSI_FOR_SCRIPTS = FSI_FOR_SCRIPTS
+      FSharpBuild = FSharpBuild
+      FSharpCompilerInteractiveSettings = FSharpCompilerInteractiveSettings
       csc_flags = csc_flags
       fsc_flags = fsc_flags 
       fsi_flags = fsi_flags 
       Directory="" 
       DotNetExe = dotNetExe
-      DotNet20Exe = dotNet20Exe
       DefaultPlatform = defaultPlatform }
 
 let logConfig (cfg: TestConfig) =
@@ -222,7 +232,6 @@ let logConfig (cfg: TestConfig) =
     log "csc_flags           =%s" cfg.csc_flags
     log "FSC                 =%s" cfg.FSC
     log "fsc_flags           =%s" cfg.fsc_flags
-    log "BINPATH             =%s" cfg.BinPath
     log "FSCOREDLLPATH       =%s" cfg.FSCOREDLLPATH
     log "FSI                 =%s" cfg.FSI
 #if !FSHARP_SUITE_DRIVES_CORECLR_TESTS
@@ -452,6 +461,7 @@ let rm cfg x = Commands.rm cfg.Directory x
 let rmdir cfg x = Commands.rmdir cfg.Directory x
 let mkdir cfg = Commands.mkdir_p cfg.Directory
 let copy_y cfg f = Commands.copy_y cfg.Directory f >> checkResult
+let copySystemValueTuple cfg = copy_y cfg (getDirectoryName(cfg.FSC) ++ "System.ValueTuple.dll") ("." ++ "System.ValueTuple.dll")
 
 let diff normalize path1 path2 =
     let result = System.Text.StringBuilder()
diff --git a/tests/fsharp/tests.fs b/tests/fsharp/tests.fs
index c9b3bb2695e..ca19aa3a7fa 100644
--- a/tests/fsharp/tests.fs
+++ b/tests/fsharp/tests.fs
@@ -1068,7 +1068,7 @@ module CoreTests =
 
         echo "Test 6================================================="
 
-        fscAppend cfg stdoutPath stderrPath "--nologo -r FSharp.Compiler.Interactive.Settings" ["usesfsi.fsx"]
+        fscAppend cfg stdoutPath stderrPath "--nologo -r \"%s\"" cfg.FSharpCompilerInteractiveSettings ["usesfsi.fsx"]
 
         echo "Test 7================================================="
 
@@ -1628,13 +1628,13 @@ module CoreTests =
     let verify () = 
         let cfg = testConfig "core/verify"
 
-        peverifyWithArgs cfg "/nologo" (cfg.BinPath ++ "FSharp.Build.dll")
+        peverifyWithArgs cfg "/nologo" (cfg.FSharpBuild)
 
-       // peverifyWithArgs cfg "/nologo /MD" (cfg.BinPath ++ "FSharp.Compiler.dll")
+       // peverifyWithArgs cfg "/nologo /MD" (getDirectoryName(cfg.FSC) ++ "FSharp.Compiler.dll")
 
-        peverifyWithArgs cfg "/nologo" (cfg.BinPath ++ "fsi.exe")
+        peverifyWithArgs cfg "/nologo" (cfg.FSI)
 
-        peverifyWithArgs cfg "/nologo" (cfg.BinPath ++ "FSharp.Compiler.Interactive.Settings.dll")
+        peverifyWithArgs cfg "/nologo" (cfg.FSharpCompilerInteractiveSettings)
 
         fsc cfg "%s -o:xmlverify.exe -g" cfg.fsc_flags ["xmlverify.fs"]
 
diff --git a/tests/fsharpqa/Source/CodeGen/EmittedIL/CompareIL.cmd b/tests/fsharpqa/Source/CodeGen/EmittedIL/CompareIL.cmd
index da8260013c7..1786d4bc552 100644
--- a/tests/fsharpqa/Source/CodeGen/EmittedIL/CompareIL.cmd
+++ b/tests/fsharpqa/Source/CodeGen/EmittedIL/CompareIL.cmd
@@ -3,7 +3,7 @@ REM == %1 --> assembly
 ildasm /TEXT /LINENUM /NOBAR "%~nx1" >"%~n1.il"
 IF NOT ERRORLEVEL 0 exit 1
 
-echo ..\..\..\..\testenv\bin\ILComparer.exe "%~n1.il.bsl" "%~n1.il"
-..\..\..\..\testenv\bin\ILComparer.exe "%~n1.il.bsl" "%~n1.il"
+echo %~dp0..\..\..\testenv\bin\ILComparer.exe "%~n1.il.bsl" "%~n1.il"
+     %~dp0..\..\..\testenv\bin\ILComparer.exe "%~n1.il.bsl" "%~n1.il"
 exit /b %ERRORLEVEL%
 
diff --git a/tests/fsharpqa/Source/CompilerOptions/fsc/codepage/E_DefaultCodePage01.fsx b/tests/fsharpqa/Source/CompilerOptions/fsc/codepage/E_DefaultCodePage01.fsx
deleted file mode 100644
index 1ed9611bb9d..00000000000
--- a/tests/fsharpqa/Source/CompilerOptions/fsc/codepage/E_DefaultCodePage01.fsx
+++ /dev/null
@@ -1,4 +0,0 @@
-// #Regression #NoMT #CompilerOptions 
-#load "FunctionalLibrary01.fs";;
-#q;;
-//<Expects status="error" span="(7,10)" id="FS0010">Unexpected character '\?' in type name$</Expects>
\ No newline at end of file
diff --git a/tests/fsharpqa/Source/CompilerOptions/fsc/codepage/env.lst b/tests/fsharpqa/Source/CompilerOptions/fsc/codepage/env.lst
index cba9684e8d0..b80eac641bd 100644
--- a/tests/fsharpqa/Source/CompilerOptions/fsc/codepage/env.lst
+++ b/tests/fsharpqa/Source/CompilerOptions/fsc/codepage/env.lst
@@ -29,8 +29,6 @@
 	SOURCE=E_RequiresParameter01.fs   TAILFLAGS="--codepage" 	# E_RequiresParameter01.fs
 	SOURCE=E_RequiresParameter01.fs   TAILFLAGS="--codepage"  FSIMODE=EXEC 	# E_RequiresParameter01.fs-fsi
 
-# Disabled due to build machine change that causes `FunctionalLibrary01.fs` to be checked out incorrectly
-#	SOURCE=E_DefaultCodePage01.fsx     COMPILE_ONLY=1   FSIMODE=EXEC	# E_DefaultCodePage01.fsx
 	SOURCE=E_DefaultCodePage02.fsx     COMPILE_ONLY=1   			# E_DefaultCodePage02.fsx
 	SOURCE=MatchingCodePage01.fsx      COMPILE_ONLY=1  SCFLAGS="--codepage:1250" FSIMODE=EXEC	# MatchingCodePage01.fsx
 
diff --git a/tests/fsharpqa/Source/run.pl b/tests/fsharpqa/Source/run.pl
index 6555341a967..bc3bd3f2fc7 100644
--- a/tests/fsharpqa/Source/run.pl
+++ b/tests/fsharpqa/Source/run.pl
@@ -265,12 +265,12 @@
      my $PEVERIFY = $ENV{PEVERIFY}; 
      unless(defined($PEVERIFY)) {
        my $scriptPath = dirname(__FILE__);
-       $PEVERIFY = "$scriptPath\\..\\testenv\\src\\PEVerify\\bin\\Release\\net472\\PEVerify.exe";
+       $PEVERIFY = "$scriptPath\\..\\..\\..\\artifacts\\bin\\PEVerify\\Release\\net472\\PEVerify.exe";
        if (-e $PEVERIFY) {
          $ENV{PEVERIFY} = $PEVERIFY;
        }
        else {
-         $ENV{PEVERIFY} = "$scriptPath\\..\\testenv\\src\\PEVerify\\bin\\Debug\\net472\\PEVerify.exe";
+         $ENV{PEVERIFY} = "$scriptPath\\..\\..\\..\\artifacts\\bin\\PEVerify\\Debug\\net472\\PEVerify.exe";
        }
      }
 
diff --git a/tests/service/Common.fs b/tests/service/Common.fs
index 2cfaf0c6119..7693993113e 100644
--- a/tests/service/Common.fs
+++ b/tests/service/Common.fs
@@ -198,7 +198,6 @@ let parseAndCheckScript (file, input) =
 let parseSourceCode (name: string, code: string) =
     let location = Path.Combine(Path.GetTempPath(),"test"+string(hash (name, code)))
     try Directory.CreateDirectory(location) |> ignore with _ -> ()
-
     let projPath = Path.Combine(location, name + ".fsproj")
     let filePath = Path.Combine(location, name + ".fs")
     let dllPath = Path.Combine(location, name + ".dll")
diff --git a/tests/service/EditorTests.fs b/tests/service/EditorTests.fs
index 5fb5249e83a..4ce255440f9 100644
--- a/tests/service/EditorTests.fs
+++ b/tests/service/EditorTests.fs
@@ -63,6 +63,12 @@ let ``Intro test`` () =
     let identToken = FSharpTokenTag.IDENT
 //    let projectOptions = checker.GetProjectOptionsFromScript(file, input) |> Async.RunSynchronously
 
+    // So we check that the messages are the same
+    for msg in typeCheckResults.Errors do 
+        printfn "Got an error, hopefully with the right text: %A" msg
+
+    printfn "typeCheckResults.Errors.Length = %d" typeCheckResults.Errors.Length
+
     // We only expect one reported error. However,
     // on Unix, using filenames like /home/user/Test.fsx gives a second copy of all parse errors due to the
     // way the load closure for scripts is generated. So this returns two identical errors
diff --git a/tests/service/FscTests.fs b/tests/service/FscTests.fs
index 57cc47083e7..f8ecbfaf4cb 100644
--- a/tests/service/FscTests.fs
+++ b/tests/service/FscTests.fs
@@ -48,7 +48,7 @@ type PEVerifier () =
             Some ("pedump", "--verify all")
         else
             let peverifyPath configuration =
-                Path.Combine(__SOURCE_DIRECTORY__, "..", "fsharpqa", "testenv", "src", "PEVerify", "bin", configuration, "net472", "PEVerify.exe")
+                Path.Combine(__SOURCE_DIRECTORY__, "..", "..", "artifacts", "bin", "PEVerify", configuration, "net472", "PEVerify.exe")
             let peverify =
                 if File.Exists(peverifyPath "Debug") then peverifyPath "Debug"
                 else peverifyPath "Release"
diff --git a/tests/service/StructureTests.fs b/tests/service/StructureTests.fs
index 9229ab6ccb5..38bb62d2d82 100644
--- a/tests/service/StructureTests.fs
+++ b/tests/service/StructureTests.fs
@@ -41,7 +41,6 @@ let (=>) (source: string) (expectedRanges: (Range * Range) list) =
     let getRange (r: range) = (r.StartLine, r.StartColumn, r.EndLine, r.EndColumn)
 
     let ast = parseSourceCode(fileName, source)
-
     try
         match ast with
         | Some tree ->
@@ -60,7 +59,7 @@ let (=>) (source: string) (expectedRanges: (Range * Range) list) =
         reraise()
 
 [<Test>]
-let ``empty file``() = "" => [ ]
+let ``empty file``() = "" => []
 
 [<Test>]
 let ``nested module``() =
@@ -68,8 +67,7 @@ let ``nested module``() =
 module MyModule =
     ()
 """
-    => [ (1, 0, 4, 0), (1, 0, 4, 0)
-         (2, 0, 3, 6), (2, 15, 3, 6) ]
+    => [ (2, 0, 3, 6), (2, 15, 3, 6) ]
 
 [<Test>]
 let ``module with multiline function``() =
@@ -78,8 +76,7 @@ module MyModule =
     let foo() =
         foo()
 """
-    => [ (1, 0, 5, 0), (1, 0, 5, 0)
-         (2, 0, 4, 13), (2, 15, 4, 13)
+    => [ (2, 0, 4, 13), (2, 15, 4, 13)
          (3, 4, 4, 13), (3, 13, 4, 13)
          (3, 8, 4, 13), (3, 13, 4, 13) ]
 
@@ -91,8 +88,7 @@ type Color =
     | Green
     | Blue
 """
-    => [ (1, 0, 6, 0), (1, 0, 6, 0)
-         (2, 5, 5, 10), (2, 11, 5, 10)
+    => [ (2, 5, 5, 10), (2, 11, 5, 10)
          (3, 4, 5, 10), (3, 4, 5, 10) ]
 
 [<Test>]
@@ -107,8 +103,7 @@ type Color =
         member __.Dispose() =
             (docEventListener :> IDisposable).Dispose()
 """
-    => [ (1, 0, 10, 0), (1, 0, 10, 0)
-         (2, 5, 9, 55), (2, 11, 9, 55)
+    => [ (2, 5, 9, 55), (2, 11, 9, 55)
          (3, 4, 5, 10), (3, 4, 5, 10)
          (7, 4, 9, 55), (7, 25, 9, 55)
          (8, 15, 9, 55), (8, 27, 9, 55)
@@ -128,8 +123,7 @@ type Color =
             (docEventListener :> IDisposable).Dispose()
 """
     =>
-    [ (1, 0, 11, 0), (1, 0, 11, 0)
-      (2, 5, 10, 55), (2, 11, 10, 55)
+    [ (2, 5, 10, 55), (2, 11, 10, 55)
       (3, 4, 4, 14), (3, 4, 4, 14)
       (3, 6, 4, 13), (3, 6, 4, 13)
       (8, 4, 10, 55), (8, 25, 10, 55)
@@ -147,8 +141,7 @@ type Color() =   // 2
         foo()
         ()       // 8
 """
-    => [ (1, 0, 9, 0), (1, 0, 9, 0)
-         (2, 5, 8, 10), (2, 11, 8, 10)
+    => [ (2, 5, 8, 10), (2, 11, 8, 10)
          (3, 8, 4, 10), (3, 13, 4, 10)
          (6, 4, 8, 10), (6, 6, 8, 10) ]
 
@@ -182,8 +175,7 @@ module MyModule =       // 2
                 member __.Dispose() =
                     (docEventListener :> IDisposable).Dispose()
 """ 
-    => [ (1, 0, 28, 0), (1, 0, 28, 0)
-         (2, 0, 27, 63), (2, 15, 27, 63)
+    => [ (2, 0, 27, 63), (2, 15, 27, 63)
          (4, 4, 5, 10), (4, 13, 5, 10)
          (4, 8, 5, 10), (4, 13, 5, 10)
          (7, 9, 15, 59), (7, 15, 15, 59)
@@ -228,8 +220,7 @@ open H
 open G             
 open H              
 """
-    => [ (1, 0, 26, 6), (1, 0, 26, 6)
-         (2, 5, 3, 6), (2, 5, 3, 6)
+    => [ (2, 5, 3, 6), (2, 5, 3, 6)
          (5, 0, 19, 17), (5, 8, 19, 17)
          (8, 9, 9, 10), (8, 9, 9, 10)
          (11, 4, 14, 17), (11, 12, 14, 17)
@@ -263,8 +254,7 @@ let x = 1
       "c" 
 #r "d"     
 """
-    => [ (1, 0, 23, 6), (1, 0, 23, 6)
-         (2, 3, 8, 6), (2, 3, 8, 6)
+    => [ (2, 3, 8, 6), (2, 3, 8, 6)
          (11, 3, 23, 6), (11, 3, 23, 6) ]
 
 [<Test>]
@@ -277,8 +267,7 @@ let f x =       // 2
         ()      // 6
     x           // 7
 """
-    => [ (1, 0, 8, 0), (1, 0, 8, 0)
-         (2, 0, 7, 5), (2, 7, 7, 5)
+    => [ (2, 0, 7, 5), (2, 7, 7, 5)
          (2, 4, 7, 5), (2, 7, 7, 5)
          (3, 8, 6, 10), (3, 11, 6, 10)
          (4, 12, 5, 14), (4, 13, 5, 14) ]
@@ -296,8 +285,7 @@ match None with     // 2
         let x = ()  // 9
         ()          // 10
 """
-    => [ (1, 0, 11, 0), (1, 0, 11, 0)
-         (2, 0, 10, 10), (2, 15, 10, 10)
+    => [ (2, 0, 10, 10), (2, 15, 10, 10)
          (6, 4, 10, 10), (5, 6, 10, 10)
          (6, 4, 10, 10), (6, 19, 10, 10)
          (9, 8, 10, 10), (8, 10, 10, 10) ]
@@ -317,8 +305,7 @@ async {                                   // 2
             ()                            // 11
 }                                         // 12
 """
-    => [ (1, 0, 12, 1), (1, 0, 12, 1)
-         (2, 0, 12, 1), (2, 7, 12, 0)
+    => [ (2, 0, 12, 1), (2, 7, 12, 0)
          (3, 4, 11, 14), (3, 37, 11, 14)
          (7, 8, 11, 14), (6, 10, 11, 14)
          (7, 8, 11, 14), (7, 23, 11, 14)
@@ -335,8 +322,7 @@ seq {              // 2
         yield () } // 7
 }                  // 8
 """
-    => [ (1, 0, 8, 1), (1, 0, 8, 1)
-         (2, 0, 8, 1), (2, 5, 8, 0)
+    => [ (2, 0, 8, 1), (2, 5, 8, 0)
          (4, 8, 5, 10), (4, 11, 5, 10)
          (6, 4, 7, 18), (6, 4, 7, 18)
          (6, 11, 7, 18), (6, 16, 7, 17) ]
@@ -348,8 +334,7 @@ let _ =
     [ 1; 2
       3 ]
 """
-  => [ (1, 0, 5, 0), (1, 0, 5, 0)
-       (2, 0, 4, 9), (2, 5, 4, 9)
+  => [ (2, 0, 4, 9), (2, 5, 4, 9)
        (2, 4, 4, 9), (2, 5, 4, 9)
        (3, 4, 4, 9), (3, 5, 4, 8) ]
 
@@ -360,8 +345,7 @@ let _ =
     { new System.IDisposable with
         member __.Dispose() = () }
 """
-    => [ (1, 0, 5, 0), (1, 0, 5, 0)
-         (2, 0, 4, 34), (2, 5, 4, 34)
+    => [ (2, 0, 4, 34), (2, 5, 4, 34)
          (2, 4, 4, 34), (2, 5, 4, 34)
          (3, 4, 4, 34), (3, 28, 4, 34) ]
          
@@ -376,8 +360,7 @@ with _ ->     // 5
         ()    // 7
     ()        // 8
 """
-    => [ (1, 0, 9, 0), (1, 0, 9, 0)
-         (2, 0, 5, 0), (2, 3, 5, 0)
+    => [ (2, 0, 5, 0), (2, 3, 5, 0)
          (2, 0, 8, 6), (2, 3, 8, 6)
          (3, 8, 4, 10), (3, 11, 4, 10)
          (5, 0, 8, 6), (5, 4, 8, 6)
@@ -395,8 +378,7 @@ finally       // 5
         ()    // 7
     ()        // 8
 """
-    => [ (1, 0, 9, 0), (1, 0, 9, 0)
-         (2, 0, 8, 6), (2, 3, 8, 6)
+    => [ (2, 0, 8, 6), (2, 3, 8, 6)
          (3, 8, 4, 10), (3, 11, 4, 10)
          (5, 0, 8, 6), (5, 7, 8, 6)
          (6, 8, 7, 10), (6, 11, 7, 10) ]
@@ -413,8 +395,7 @@ else
         ()
     ()
 """
-    => [ (1, 0, 10, 0), (1, 0, 10, 0)
-         (2, 0, 9, 6), (2, 7, 9, 6)
+    => [ (2, 0, 9, 6), (2, 7, 9, 6)
          (2, 8, 5, 6), (2, 12, 5, 6)
          (3, 8, 4, 10), (3, 11, 4, 10)
          (7, 8, 8, 10), (7, 11, 8, 10) ]
@@ -426,8 +407,7 @@ let ``code quotation``() =
   "code"
         @>
 """
-    => [ (1, 0, 4, 10), (1, 0, 4, 10)
-         (2, 0, 4, 10), (2, 2, 4, 8) ]
+    => [ (2, 0, 4, 10), (2, 2, 4, 8) ]
 
 [<Test>]
 let ``raw code quotation``() =
@@ -436,8 +416,7 @@ let ``raw code quotation``() =
   "code"
         @@>
 """
-    => [ (1, 0, 4, 11), (1, 0, 4, 11)
-         (2, 0, 4, 11), (2, 3, 4, 8) ]
+    => [ (2, 0, 4, 11), (2, 3, 4, 8) ]
 
 [<Test>]
 let ``match lambda aka function``() =
@@ -446,8 +425,7 @@ function
 | 0 ->  ()
         ()
 """
-    => [ (1, 0, 5, 0), (1, 0, 5, 0)
-         (2, 0, 4, 10), (2, 8, 4, 10)
+    => [ (2, 0, 4, 10), (2, 8, 4, 10)
          (3, 8, 4, 10), (3, 3, 4, 10) ]
 
 [<Test>]
@@ -458,8 +436,7 @@ let matchwith num =
     | 0 -> ()
            ()
 """
-    =>  [ (1, 0, 6, 0), (1, 0, 6, 0)
-          (2, 0, 5, 13), (2, 17, 5, 13)
+    =>  [ (2, 0, 5, 13), (2, 17, 5, 13)
           (2, 4, 5, 13), (2, 17, 5, 13)
           (3, 4, 5, 13), (3, 18, 5, 13)
           (4, 11, 5, 13), (4, 7, 5, 13) ]
@@ -471,8 +448,7 @@ for x = 100 downto 10 do
     ()
     ()
 """
-    => [ (1, 0, 5, 0), (1, 0, 5, 0)
-         (2, 0, 4, 6), (2, 0, 4, 6) ]
+    => [ (2, 0, 4, 6), (2, 0, 4, 6) ]
 
 [<Test>]
 let ``for each``() =
@@ -481,8 +457,7 @@ for x in 0 .. 100 ->
             ()
             ()
 """
-    =>  [ (1, 0, 5, 0), (1, 0, 5, 0)
-          (2, 0, 4, 14), (2, 0, 4, 14)
+    =>  [ (2, 0, 4, 14), (2, 0, 4, 14)
           (2, 18, 4, 14), (2, 18, 4, 14) ]
    
 [<Test>]
@@ -492,8 +467,7 @@ let ``tuple``() =
 , 322
 , 123123 )
 """
-    => [ (1, 0, 4, 10), (1, 0, 4, 10)
-         (2, 2, 4, 8), (2, 2, 4, 8) ]
+    => [ (2, 2, 4, 8), (2, 2, 4, 8) ]
 
 [<Test>]
 let ``do!``() =
@@ -502,8 +476,7 @@ do!
     printfn "allo"
     printfn "allo"
 """
-    =>  [(1, 0, 5, 0), (1, 0, 5, 0)
-         (2, 0, 4, 18), (2, 3, 4, 18)]
+    =>  [ (2, 0, 4, 18), (2, 3, 4, 18) ]
 
 [<Test>]
 let ``cexpr yield yield!``() =
@@ -517,11 +490,10 @@ cexpr{
                 }
     }
 """
-    =>  [(1, 0, 9, 5), (1, 0, 9, 5)
-         (2, 0, 9, 5), (2, 6, 9, 4)
-         (3, 4, 8, 17), (3, 4, 8, 17)
-         (4, 8, 8, 17), (4, 14, 8, 16)
-         (5, 20, 7, 26), (5, 20, 7, 26)]
+    =>  [ (2, 0, 9, 5), (2, 6, 9, 4)
+          (3, 4, 8, 17), (3, 4, 8, 17)
+          (4, 8, 8, 17), (4, 14, 8, 16)
+          (5, 20, 7, 26), (5, 20, 7, 26) ]
 
 [<Test>]
 let ``XML doc comments``() =
@@ -539,8 +511,7 @@ module M =
     /// Single line comment
     let f x = x
 """
-    => [ (1, 0, 14, 0), (1, 0, 14, 0)
-         (2, 0, 3, 10), (2, 0, 3, 10)
+    => [ (2, 0, 3, 10), (2, 0, 3, 10)
          (4, 0, 13, 15), (4, 8, 13, 15)
          (5, 4, 6, 14), (5, 4, 6, 14)
          (7, 9, 11, 19), (7, 11, 11, 19)
@@ -562,8 +533,7 @@ module M =
     // Single line comment
     let f x = x
 """
-    => [ (1, 0, 14, 0), (1, 0, 14, 0)
-         (2, 0, 3, 9), (2, 0, 3, 9)
+    => [ (2, 0, 3, 9), (2, 0, 3, 9)
          (4, 0, 13, 15), (4, 8, 13, 15)
          (5, 4, 6, 13), (5, 4, 6, 13)
          (7, 9, 11, 19), (7, 11, 11, 19)
@@ -582,8 +552,7 @@ let ``XML doc and regular comments in one block``() =
 /// Line 8
 /// Line 9
 """
-    => [ (1, 0, 11, 0), (1, 0, 11, 0)
-         (2, 0, 3, 9), (2, 0, 3, 9)
+    => [ (2, 0, 3, 9), (2, 0, 3, 9)
          (4, 0, 5, 10), (4, 0, 5, 10)
          (7, 0, 10, 10), (7, 0, 10, 10) ]
 
@@ -596,9 +565,45 @@ module M =
             'c',
             1)
 """
-    => [ (1, 0, 7, 0), (1, 0, 7, 0)
-         (2, 0, 6, 14), (2, 8, 6, 14)
+    => [ (2, 0, 6, 14), (2, 8, 6, 14)
          (3, 4, 6, 14), (3, 9, 6, 14)
          (3, 8, 6, 14), (3, 9, 6, 14)
          (4, 8, 6, 14), (4, 25, 6, 14)
          (5, 12, 6, 13), (5, 12, 6, 13) ]
+
+[<Test>]
+let ``Top level module`` () =
+    """
+module TopLevelModule
+
+module Nested =
+    let x = 123
+"""
+    => [ (2, 7, 5, 15), (2, 21, 5, 15)
+         (4, 0, 5, 15), (4, 13, 5, 15) ]
+
+[<Test>]
+let ``Top level namespace`` () =
+    """
+namespace TopLevelNamespace.Another
+
+module Nested =
+    let x = 123
+"""
+    => [ (4, 0, 5, 15), (4, 13, 5, 15) ]
+
+[<Test>]
+let ``Multiple namespaces`` () =
+    """
+namespace TopLevelNamespace.Another
+
+module Nested =
+    let x = 123
+
+namespace AnotherTopLevel.Nested
+
+module NestedModule =
+    let x = 123
+"""
+    => [ (4, 0, 5, 15), (4, 13, 5, 15)
+         (9, 0, 10, 15), (9, 19, 10, 15) ]
diff --git a/tests/service/Symbols.fs b/tests/service/Symbols.fs
index 8b5749f0546..da2a7795577 100644
--- a/tests/service/Symbols.fs
+++ b/tests/service/Symbols.fs
@@ -100,4 +100,27 @@ module Mod2 =
          mod1val1.XmlDocSig |> shouldEqual "P:Mod1.val1"
          mod2func2.XmlDocSig |> shouldEqual "M:Mod1.Mod2.func2"
 
-                 
\ No newline at end of file
+
+module Attributes =
+    [<Test>]
+    let ``Emit conditional attributes`` () =
+        let source = """
+open System
+open System.Diagnostics
+
+[<Conditional("Bar")>]
+type FooAttribute() =
+    inherit Attribute()
+
+[<Foo>]
+let x = 123
+"""
+        let fileName, options = mkTestFileAndOptions source [| "--noconditionalerasure" |]
+        let _, checkResults = parseAndCheckFile fileName source options
+
+        checkResults.GetAllUsesOfAllSymbolsInFile()
+         |> Async.RunSynchronously
+         |> Array.tryFind (fun su -> su.Symbol.DisplayName = "x")
+         |> Option.orElseWith (fun _ -> failwith "Could not get symbol")
+         |> Option.map (fun su -> su.Symbol :?> FSharpMemberOrFunctionOrValue)
+         |> Option.iter (fun symbol -> symbol.Attributes.Count |> shouldEqual 1)
diff --git a/tests/service/TreeVisitorTests.fs b/tests/service/TreeVisitorTests.fs
new file mode 100644
index 00000000000..aee58607ba0
--- /dev/null
+++ b/tests/service/TreeVisitorTests.fs
@@ -0,0 +1,25 @@
+module Tests.Service.TreeVisitorTests
+
+open FSharp.Compiler.Service.Tests.Common
+open Microsoft.FSharp.Compiler.Range
+open Microsoft.FSharp.Compiler.SourceCodeServices.AstTraversal
+open NUnit.Framework
+
+[<Test>]
+let ``Visit type test`` () =
+    let visitor =
+        { new AstVisitorBase<_>() with
+            member x.VisitExpr(_, _, defaultTraverse, expr) = defaultTraverse expr
+            member x.VisitType(_, _) = Some () }
+
+    let source = "123 :? int"
+    let parseTree =
+        match parseSourceCode("C:\\test.fs", source) with
+        | None -> failwith "No parse tree"
+        | Some parseTree -> parseTree
+
+    Traverse(mkPos 1 11, parseTree, visitor)
+    |> Option.defaultWith (fun _ -> failwith "Did not visit type")
+
+    Traverse(mkPos 1 3, parseTree, visitor)
+    |> Option.iter (fun _ -> failwith "Should not visit type")
diff --git a/verify-translations.cmd b/verify-translations.cmd
index 6717de0f778..2580890c6fb 100644
--- a/verify-translations.cmd
+++ b/verify-translations.cmd
@@ -1,3 +1,3 @@
 @echo off
 
-%~dp0release\net40\bin\fsi.exe %~dp0src\scripts\VerifyAllTranslations.fsx -- %~dp0
+%~dp0artifacts\bin\fsi\Release\net46\fsi.exe %~dp0src\scripts\VerifyAllTranslations.fsx -- %~dp0
diff --git a/vsintegration/ItemTemplates/.gitignore b/vsintegration/ItemTemplates/.gitignore
new file mode 100644
index 00000000000..cd42ee34e87
--- /dev/null
+++ b/vsintegration/ItemTemplates/.gitignore
@@ -0,0 +1,2 @@
+bin/
+obj/
diff --git a/vsintegration/ProjectTemplates/.gitignore b/vsintegration/ProjectTemplates/.gitignore
new file mode 100644
index 00000000000..cd42ee34e87
--- /dev/null
+++ b/vsintegration/ProjectTemplates/.gitignore
@@ -0,0 +1,2 @@
+bin/
+obj/
diff --git a/vsintegration/Templates.Directory.Build.props b/vsintegration/Templates.Directory.Build.props
index c9d39a043eb..088d6a4867d 100644
--- a/vsintegration/Templates.Directory.Build.props
+++ b/vsintegration/Templates.Directory.Build.props
@@ -2,6 +2,12 @@
 
   <Import Project="Directory.Build.props" />
 
+  <!-- The VSSDK can't handle these values being fully qualified.  The ~hack~ fix is to unset them and manually copy the templates after the build. -->
+  <PropertyGroup>
+    <BaseOutputPath></BaseOutputPath>
+    <BaseIntermediateOutputPath></BaseIntermediateOutputPath>
+  </PropertyGroup>
+
   <PropertyGroup>
     <TargetFramework>net472</TargetFramework>
     <TargetFrameworkVersion>v4.7.2</TargetFrameworkVersion>
diff --git a/vsintegration/Templates.Directory.Build.targets b/vsintegration/Templates.Directory.Build.targets
index 84513c489fc..4d8df139274 100644
--- a/vsintegration/Templates.Directory.Build.targets
+++ b/vsintegration/Templates.Directory.Build.targets
@@ -11,4 +11,21 @@
 
   <Target Name="CoreCompile" />
 
+  <!-- The templates have to build to directories relative to their projects, this target copies the relevant files to the appropriate output location. -->
+  <Target Name="CopyTemplatesToOutputDirectory"
+          AfterTargets="Build">
+
+    <PropertyGroup>
+      <TemplatesRootPath>$(OutputPath)$(TemplateCategory)\FSharp</TemplatesRootPath>
+      <TemplatesRootPath Condition="!$([System.IO.Path]::IsPathRooted('$(TemplatesRootPath)'))">$(MSBuildProjectDirectory)\$(TemplatesRootPath)</TemplatesRootPath>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <Templates Include="$(TemplatesRootPath)\**\*.zip" />
+    </ItemGroup>
+
+    <Copy SourceFiles="@(Templates)" DestinationFolder="$(ArtifactsBinDir)\$(MSBuildProjectName)\$(Configuration)\%(Templates.RecursiveDir)" />
+
+  </Target>
+
 </Project>
diff --git a/vsintegration/Vsix/Directory.Build.targets b/vsintegration/Vsix/Directory.Build.targets
index fa37bc2cd13..677cf0afc9d 100644
--- a/vsintegration/Vsix/Directory.Build.targets
+++ b/vsintegration/Vsix/Directory.Build.targets
@@ -2,6 +2,11 @@
 
   <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.targets', '$(MSBuildThisFileDirectory)../'))" />
 
+  <PropertyGroup>
+    <BaseOutputPath>$(ArtifactsDir)\VSSetup\$(Configuration)</BaseOutputPath>
+    <BaseIntermediateOutputPath>$(ArtifactsDir)\VSSetup.obj\$(Configuration)\Microsoft.FSharp\</BaseIntermediateOutputPath>
+  </PropertyGroup>
+
   <ItemGroup>
     <BootstrapperPackage Include=".NETFramework,Version=v4.6">
       <Visible>False</Visible>
diff --git a/vsintegration/Vsix/VisualFSharpFull/VisualFSharpFull.csproj b/vsintegration/Vsix/VisualFSharpFull/VisualFSharpFull.csproj
index aed53275a11..e3c60441449 100644
--- a/vsintegration/Vsix/VisualFSharpFull/VisualFSharpFull.csproj
+++ b/vsintegration/Vsix/VisualFSharpFull/VisualFSharpFull.csproj
@@ -85,7 +85,7 @@
       <Private>True</Private>
       <AdditionalProperties>TargetFramework=net45</AdditionalProperties>
     </ProjectReference>
-    <ProjectReference Include="..\..\..\src\fsharp\fsiAnyCpu\FsiAnyCPU.fsproj">
+    <ProjectReference Include="..\..\..\src\fsharp\fsiAnyCpu\fsiAnyCPU.fsproj">
       <Project>{8B3E283D-B5FE-4055-9D80-7E3A32F3967B}</Project>
       <Name>FsiAnyCPU</Name>
       <IncludeOutputGroupsInVSIX>BuiltProjectOutputGroup%3bGetCopyToOutputDirectoryItems%3b</IncludeOutputGroupsInVSIX>
@@ -97,7 +97,7 @@
       <Private>True</Private>
       <AdditionalProperties>TargetFramework=net472</AdditionalProperties>
     </ProjectReference>
-    <ProjectReference Include="..\..\..\src\fsharp\fsi\Fsi.fsproj">
+    <ProjectReference Include="..\..\..\src\fsharp\fsi\fsi.fsproj">
       <Project>{D0E98C0D-490B-4C61-9329-0862F6E87645}</Project>
       <Name>Fsi</Name>
       <IncludeOutputGroupsInVSIX>BuiltProjectOutputGroup%3bGetCopyToOutputDirectoryItems%3b</IncludeOutputGroupsInVSIX>
@@ -109,7 +109,7 @@
       <Private>True</Private>
       <AdditionalProperties>TargetFramework=net472</AdditionalProperties>
     </ProjectReference>
-    <ProjectReference Include="..\..\..\src\fsharp\Fsc\Fsc.fsproj">
+    <ProjectReference Include="..\..\..\src\fsharp\fsc\fsc.fsproj">
       <Project>{C94C257C-3C0A-4858-B5D8-D746498D1F08}</Project>
       <Name>fsc</Name>
       <IncludeOutputGroupsInVSIX>BuiltProjectOutputGroup%3bGetCopyToOutputDirectoryItems%3b</IncludeOutputGroupsInVSIX>
diff --git a/vsintegration/Vsix/VisualFSharpTemplates/VisualFSharpTemplates.csproj b/vsintegration/Vsix/VisualFSharpTemplates/VisualFSharpTemplates.csproj
index 0267329af35..110fc964e1c 100644
--- a/vsintegration/Vsix/VisualFSharpTemplates/VisualFSharpTemplates.csproj
+++ b/vsintegration/Vsix/VisualFSharpTemplates/VisualFSharpTemplates.csproj
@@ -6,7 +6,6 @@
     <AssemblyName>VisualFSharpTemplate</AssemblyName>
     <OutputType>Library</OutputType>
     <ExtensionInstallationFolder>Microsoft\FSharpTemplates</ExtensionInstallationFolder>
-    <DeployExtension>true</DeployExtension>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/vsintegration/src/Directory.Build.props b/vsintegration/src/Directory.Build.props
new file mode 100644
index 00000000000..1ad6fb80ecd
--- /dev/null
+++ b/vsintegration/src/Directory.Build.props
@@ -0,0 +1,9 @@
+<Project>
+
+  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
+
+  <PropertyGroup>
+    <DeployExtension>false</DeployExtension>
+  </PropertyGroup>
+
+</Project>
diff --git a/vsintegration/src/FSharp.ProjectSystem.PropertyPages/FSharp.PropertiesPages.vbproj b/vsintegration/src/FSharp.ProjectSystem.PropertyPages/FSharp.PropertiesPages.vbproj
index 262612d8f81..a1bdf05aba8 100644
--- a/vsintegration/src/FSharp.ProjectSystem.PropertyPages/FSharp.PropertiesPages.vbproj
+++ b/vsintegration/src/FSharp.ProjectSystem.PropertyPages/FSharp.PropertiesPages.vbproj
@@ -4,8 +4,7 @@
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
-    <TargetDotnetProfile Condition=" '$(TargetDotnetProfile)' == '' ">net40</TargetDotnetProfile>
-    <OutputPath>$(FSharpSourcesRoot)\..\$(Configuration)\$(TargetDotnetProfile)\bin</OutputPath>
+    <OutputPath>$(ArtifactsBinDir)\$(MSBuildProjectName)\$(Configuration)\$(TargetFramework)</OutputPath>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
     <ProductVersion>9.0.21022</ProductVersion>
     <SchemaVersion>2.0</SchemaVersion>
@@ -25,6 +24,9 @@
     <WarningsAsErrors>41999,42016,42017,42018,42019,42020,42021,42022,42032,42036</WarningsAsErrors>
     <NoWarn>40026;42105;42107;42353</NoWarn>
     <TargetFrameworkVersion>v4.7.2</TargetFrameworkVersion>
+    <RuntimeIdentifiers>win</RuntimeIdentifiers>
+    <TargetFrameworkProfile>
+    </TargetFrameworkProfile>
     <ImportVsSDK>true</ImportVsSDK>
     <CreateVsixContainer>false</CreateVsixContainer>
     <DeployExtension>false</DeployExtension>
diff --git a/vsintegration/src/FSharp.VS.FSI/FSharp.VS.FSI.fsproj b/vsintegration/src/FSharp.VS.FSI/FSharp.VS.FSI.fsproj
index fcab1fdf8bc..b057f0f8204 100644
--- a/vsintegration/src/FSharp.VS.FSI/FSharp.VS.FSI.fsproj
+++ b/vsintegration/src/FSharp.VS.FSI/FSharp.VS.FSI.fsproj
@@ -29,7 +29,6 @@
     <Compile Include="$(FSharpSourcesRoot)\utils\CompilerLocationUtils.fs">
       <Link>CompilerLocationUtils.fs</Link>
     </Compile>
-    <Compile Include="quickparse.fs" />
     <Compile Include="sessions.fs" />
     <Compile Include="fsiBasis.fs" />
     <Compile Include="fsiLanguageService.fs" />
diff --git a/vsintegration/src/FSharp.VS.FSI/quickparse.fs b/vsintegration/src/FSharp.VS.FSI/quickparse.fs
deleted file mode 100644
index 9099134a660..00000000000
--- a/vsintegration/src/FSharp.VS.FSI/quickparse.fs
+++ /dev/null
@@ -1,80 +0,0 @@
-// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.
-
-namespace Microsoft.VisualStudio.FSharp.Interactive
-open System.Globalization
-
-// Duplication note:
-//      Inlined from Language Service.
-//      If/when there is a common DLL this code can be shared.
-
-/// Methods for cheaply and innacurately parsing F#
-module internal QuickParse =
-    /// The characters that are allowed to be in an identifier.
-    let private IsIdentifierPartCharacter c =
-        let cat = System.Char.GetUnicodeCategory(c)
-        (
-        // Letters
-           cat = UnicodeCategory.UppercaseLetter 
-        || cat = UnicodeCategory.LowercaseLetter 
-        || cat = UnicodeCategory.TitlecaseLetter
-        || cat = UnicodeCategory.ModifierLetter
-        || cat = UnicodeCategory.OtherLetter
-        || cat = UnicodeCategory.LetterNumber 
-        // Numbers
-        || cat = UnicodeCategory.DecimalDigitNumber
-        // Connectors
-        || cat = UnicodeCategory.ConnectorPunctuation 
-        // Combiners
-        || cat = UnicodeCategory.NonSpacingMark 
-        || cat = UnicodeCategory.SpacingCombiningMark
-        ) 
-    /// Is this character a part of a long identifier 
-    let private IsLongIdentifierPartCharacter c = 
-        (IsIdentifierPartCharacter c) || (c='.')
-    /// Given a line of text and an index into the line return the
-    /// "island" of text that could be an identifier around index.
-    let GetIdentifierIsland(line:string,index)= 
-        if index<line.Length then 
-            let hoverChar = line.[index]
-            if not (IsLongIdentifierPartCharacter hoverChar) then 
-                // The character is not an identifier character. Return nothing
-                None
-            else
-                let mutable left = index
-                let mutable right = if line.[index]='.' then index+1 else index
-                let len = line.Length
-                while left>=0 && IsLongIdentifierPartCharacter line.[left] do left<-left-1
-                while right<len && IsIdentifierPartCharacter line.[right] do right<-right+1
-                let result = line.Substring(left+1,right-left-1)
-                Some(result)
-        else
-            None
-    /// Get the partial long name of the identifier to the left of index.
-    let GetPartialLongName(line:string,index) =
-        let IsIdentifierPartCharacter(pos) = IsIdentifierPartCharacter(line.[pos])
-        let IsLongIdentifierPartCharacter(pos) = IsLongIdentifierPartCharacter(line.[pos])
-        let IsDot(pos) = line.[pos]='.'
-
-        let rec InLeadingIdentifier(pos,right,prior) = 
-            let PushName() = 
-                (line.Substring(pos+1,right-pos-1),None)::prior
-            if pos < 0 then PushName()
-            else if IsIdentifierPartCharacter(pos) then InLeadingIdentifier(pos-1,right,prior)
-            else if IsDot(pos) then InLeadingIdentifier(pos-1,pos,PushName())
-            else PushName()
-        let rec InName(pos,startResidue,right) =
-            let NameAndResidue() = 
-                [line.Substring(pos+1,startResidue-pos-1),Some(line.Substring(startResidue+1,right-startResidue))]
-            if pos < 0 then [line.Substring(pos+1,startResidue-pos-1),Some(line.Substring(startResidue+1,right-startResidue))]
-            else if IsIdentifierPartCharacter(pos) then InName(pos-1,startResidue,right) 
-            else if IsDot(pos) then InLeadingIdentifier(pos-1,pos,NameAndResidue())
-            else NameAndResidue()
-        and InResidueOrName(pos,right) =
-            if pos < 0 then [line.Substring(pos+1,right-pos),None]
-            else if IsDot(pos) then InName(pos-1,pos,right)
-            else if IsLongIdentifierPartCharacter(pos) then InResidueOrName(pos-1, right)
-            else [line.Substring(pos+1,right-pos),None]
-            
-        let result = InResidueOrName(index,index)
-        result
-           
diff --git a/vsintegration/tests/GetTypesVSUnitTests/GetTypesVSUnitTests.fsproj b/vsintegration/tests/GetTypesVSUnitTests/GetTypesVSUnitTests.fsproj
index e8f4ce2b983..b3c39992a10 100644
--- a/vsintegration/tests/GetTypesVSUnitTests/GetTypesVSUnitTests.fsproj
+++ b/vsintegration/tests/GetTypesVSUnitTests/GetTypesVSUnitTests.fsproj
@@ -9,6 +9,7 @@
     <EnableDefaultEmbeddedResourceItems>false</EnableDefaultEmbeddedResourceItems>
     <NoMsbuild>true</NoMsbuild>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
+    <UseAssetTargetFallback>true</UseAssetTargetFallback>
     <IsTestProject>true</IsTestProject>
   </PropertyGroup>
 
@@ -20,6 +21,7 @@
 
   <ItemGroup>
     <PackageReference Include="EnvDTE80" Version="$(EnvDTE80PackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;build;analyzers;native" />
+    <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.11.0" Version="$(MicrosoftVisualStudioShellInterop110PackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;build;analyzers;native" />
     <PackageReference Include="NUnit" Version="$(NUnitPackageVersion)" />
     <PackageReference Include="VSSDK.VSLangProj.8" Version="$(VSSDKVSLangProj8PackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;build;analyzers;native" />
   </ItemGroup>
diff --git a/vsintegration/tests/Salsa/salsa.fs b/vsintegration/tests/Salsa/salsa.fs
index 062e24ab198..f266f6f1d01 100644
--- a/vsintegration/tests/Salsa/salsa.fs
+++ b/vsintegration/tests/Salsa/salsa.fs
@@ -43,13 +43,13 @@ module internal Salsa =
             { new System.IDisposable with
                     member this.Dispose() = actuallyBuild <- true }
         member th.Results = capturedFlags, capturedSources
-        member th.Compile(compile:System.Func<int>, flags:string[], sources:string[]) = 
+        member th.Compile(compile:System.Func<int>, flags:string[], sources:string[]) =
             capturedFlags <- flags 
             capturedSources <- sources
             if actuallyBuild then
                 compile.Invoke()
             else
-                0         
+                0
         interface ITaskHost
         
     type BuildResult = {
diff --git a/vsintegration/tests/UnitTests/LegacyLanguageService/Tests.LanguageService.ParameterInfo.fs b/vsintegration/tests/UnitTests/LegacyLanguageService/Tests.LanguageService.ParameterInfo.fs
index bcb512a94eb..058fe998a13 100644
--- a/vsintegration/tests/UnitTests/LegacyLanguageService/Tests.LanguageService.ParameterInfo.fs
+++ b/vsintegration/tests/UnitTests/LegacyLanguageService/Tests.LanguageService.ParameterInfo.fs
@@ -435,19 +435,15 @@ type UsingMSBuild()  =
                 | [] -> System.String.Format((*Mark*)
                 | x :: xs -> f xs"""
         // Note, 3 of these 8 are only available on .NET 4.6.1.  On .NET 4.5 only 5 overloads are returned.
-        let expected45 =  [["format"; "arg0"];                                  //Net4.5
-                           ["format"; "args"];                                  //Net4.5
-                           ["provider"; "format"; "args"];                      //Net4.5
-                           ["format"; "arg0"; "arg1"];                          //Net4.5
-                           ["format"; "arg0"; "arg1"; "arg2"]]                  //Net4.5
-        let expected461 = [["provider"; "format"; "arg0"];                      //Net4.6.1
-                           ["provider"; "format"; "arg0"; "arg1"];              //Net4.6.1
-                           ["provider"; "format"; "arg0"; "arg1"; "arg2"]]      //Net4.6.1
-
-        let expected =
-            if Environment.Version.CompareTo(v461) >= 0 then
-                List.concat [expected45;expected461]
-            else expected45
+        let expected =  [["format"; "arg0"];                                  //Net4.5
+                         ["format"; "args"];                                  //Net4.5
+                         ["provider"; "format"; "args"];                      //Net4.5
+                         ["format"; "arg0"; "arg1"];                          //Net4.5
+                         ["format"; "arg0"; "arg1"; "arg2"];                  //Net4.5
+                         ["provider"; "format"; "arg0"];                      //Net4.6.1
+                         ["provider"; "format"; "arg0"; "arg1"];              //Net4.6.1
+                         ["provider"; "format"; "arg0"; "arg1"; "arg2"]]      //Net4.6.1
+
         this.VerifyParameterInfoAtStartOfMarker(fileContent,"(*Mark*)", expected)
 
     (* --- Parameter Info Systematic Tests ------------------------------------------------- *)
diff --git a/vsintegration/tests/UnitTests/Tests.Build.fs b/vsintegration/tests/UnitTests/Tests.Build.fs
index 2263fc57674..b71a43661d0 100644
--- a/vsintegration/tests/UnitTests/Tests.Build.fs
+++ b/vsintegration/tests/UnitTests/Tests.Build.fs
@@ -40,8 +40,8 @@ type MyLogger(f : string -> unit) =
 type FauxHostObject() =
     let mutable myFlags : string[] = null
     let mutable mySources : string[] = null
-    member x.Compile(compile:System.Func<int>, flags:string[], sources:string[]) = 
-        myFlags <- flags        
+    member x.Compile(compile:System.Func<int>, flags:string[], sources:string[]) =
+        myFlags <- flags
         mySources <- sources
         0
     member x.Flags = myFlags
@@ -301,7 +301,7 @@ type Build() =
                      "--fullpaths" + Environment.NewLine +
                      "--flaterrors" + Environment.NewLine +
                      "--highentropyva-" + Environment.NewLine +
-                     "--nocopyfsharpcore"  + Environment.NewLine)
+                     "--nocopyfsharpcore" + Environment.NewLine)
                     cmd
 
     [<Test>]
@@ -485,7 +485,7 @@ type Build() =
                      "--fullpaths" + Environment.NewLine +
                      "--flaterrors" + Environment.NewLine +
                      "--highentropyva-" + Environment.NewLine +
-                     "--nocopyfsharpcore" + Environment.NewLine )
+                     "--nocopyfsharpcore" + Environment.NewLine)
                     cmd
 
     [<Test>]
@@ -501,7 +501,7 @@ type Build() =
                      "--fullpaths" + Environment.NewLine +
                      "--flaterrors" + Environment.NewLine +
                      "--highentropyva-" + Environment.NewLine +
-                     "--nocopyfsharpcore" + Environment.NewLine )
+                     "--nocopyfsharpcore" + Environment.NewLine)
                     cmd
 
     [<Test>]
@@ -517,7 +517,7 @@ type Build() =
                      "--fullpaths" + Environment.NewLine +
                      "--flaterrors" + Environment.NewLine +
                      "--highentropyva-" + Environment.NewLine +
-                     "--nocopyfsharpcore" + Environment.NewLine )
+                     "--nocopyfsharpcore" + Environment.NewLine)
                     cmd
 
     [<Test>]
@@ -532,7 +532,7 @@ type Build() =
                      "--fullpaths" + Environment.NewLine +
                      "--flaterrors" + Environment.NewLine +
                      "--highentropyva-" + Environment.NewLine +
-                     "--nocopyfsharpcore" + Environment.NewLine )
+                     "--nocopyfsharpcore" + Environment.NewLine)
                     cmd
 
     [<Test>]
@@ -547,7 +547,7 @@ type Build() =
                      "--fullpaths" + Environment.NewLine +
                      "--flaterrors" + Environment.NewLine +
                      "--highentropyva-" + Environment.NewLine +
-                     "--nocopyfsharpcore" + Environment.NewLine )
+                     "--nocopyfsharpcore" + Environment.NewLine)
                     cmd
 
     [<Test>]
@@ -562,7 +562,7 @@ type Build() =
                      "--fullpaths" + Environment.NewLine +
                      "--flaterrors" + Environment.NewLine +
                      "--highentropyva-" + Environment.NewLine +
-                     "--nocopyfsharpcore" + Environment.NewLine )
+                     "--nocopyfsharpcore" + Environment.NewLine)
                     cmd 
 
     [<Test>]
@@ -576,7 +576,7 @@ type Build() =
                      "--fullpaths" + Environment.NewLine +
                      "--flaterrors" + Environment.NewLine +
                      "--highentropyva+" + Environment.NewLine +
-                     "--nocopyfsharpcore" + Environment.NewLine )
+                     "--nocopyfsharpcore" + Environment.NewLine)
                     cmd 
 
     [<Test>]
@@ -591,7 +591,7 @@ type Build() =
                      "--flaterrors" + Environment.NewLine +
                      "--subsystemversion:6.02" + Environment.NewLine +
                      "--highentropyva-" + Environment.NewLine +
-                     "--nocopyfsharpcore" + Environment.NewLine )
+                     "--nocopyfsharpcore" + Environment.NewLine)
                     cmd 
 
     [<Test>]
diff --git a/vsintegration/tests/UnitTests/VisualFSharp.UnitTests.fsproj b/vsintegration/tests/UnitTests/VisualFSharp.UnitTests.fsproj
index 1d4564108d2..072876386dc 100644
--- a/vsintegration/tests/UnitTests/VisualFSharp.UnitTests.fsproj
+++ b/vsintegration/tests/UnitTests/VisualFSharp.UnitTests.fsproj
@@ -12,6 +12,7 @@
     <UsePackageTargetFallbackHack>true</UsePackageTargetFallbackHack>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
     <EnableDefaultEmbeddedResourceItems>false</EnableDefaultEmbeddedResourceItems>
+    <UseAssetTargetFallback>true</UseAssetTargetFallback>
     <IsTestProject>true</IsTestProject>
   </PropertyGroup>
 
@@ -107,6 +108,9 @@
     <Compile Include="UnusedOpensTests.fs">
       <Link>CompilerService\UnusedOpensTests.fs</Link>
     </Compile>
+    <Compile Include="..\..\..\tests\service\TreeVisitorTests.fs">
+      <Link>CompilerService\TreeVisitorTests.fs</Link>
+    </Compile>
     <Compile Include="SyntacticColorizationServiceTests.fs">
       <Link>Roslyn\SyntacticColorizationServiceTests.fs</Link>
     </Compile>
@@ -156,11 +160,11 @@
     <Compile Include="DocumentHighlightsServiceTests.fs">
       <Link>Roslyn\DocumentHighlightsServiceTests.fs</Link>
     </Compile>
-    <None Include="App.config" />
     <None Include="App.config" CopyToOutputDirectory="PreserveNewest" />
     <None Include="app.runsettings" />
   </ItemGroup>
   <ItemGroup>
+    <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\fsc\fsc.fsproj" />
     <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Build\FSharp.Build.fsproj" />
     <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Core\FSharp.Core.fsproj" />
     <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj" />
@@ -173,6 +177,23 @@
     <ProjectReference Include="..\..\..\tests\service\data\CSharp_Analysis\CSharp_Analysis.csproj" />
   </ItemGroup>
 
+  <!-- assemblies used during tests -->
+  <ItemGroup>
+    <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Compiler.Interactive.Settings\FSharp.Compiler.Interactive.Settings.fsproj" Private="true" />
+    <ProjectReference Include="..\MockTypeProviders\DefinitionLocationAttribute\DefinitionLocationAttribute.csproj" Private="true" />
+    <ProjectReference Include="..\MockTypeProviders\DefinitionLocationAttributeFileDoesnotExist\DefinitionLocationAttributeFileDoesnotExist.csproj" Private="true" />
+    <ProjectReference Include="..\MockTypeProviders\DefinitionLocationAttributeLineDoesnotExist\DefinitionLocationAttributeLineDoesnotExist.csproj" Private="true" />
+    <ProjectReference Include="..\MockTypeProviders\DefinitionLocationAttributeWithSpaceInTheType\DefinitionLocationAttributeWithSpaceInTheType.csproj" Private="true" />
+    <ProjectReference Include="..\MockTypeProviders\DummyProviderForLanguageServiceTesting\DummyProviderForLanguageServiceTesting.fsproj" Private="true" />
+    <ProjectReference Include="..\MockTypeProviders\EditorHideMethodsAttribute\EditorHideMethodsAttribute.csproj" Private="true" />
+    <ProjectReference Include="..\MockTypeProviders\EmptyAssembly\EmptyAssembly.fsproj" Private="true" />
+    <ProjectReference Include="..\MockTypeProviders\XmlDocAttributeWithAdequateComment\XmlDocAttributeWithAdequateComment.csproj" Private="true" />
+    <ProjectReference Include="..\MockTypeProviders\XmlDocAttributeWithEmptyComment\XmlDocAttributeWithEmptyComment.csproj" Private="true" />
+    <ProjectReference Include="..\MockTypeProviders\XmlDocAttributeWithLocalizedComment\XmlDocAttributeWithLocalizedComment.csproj" Private="true" />
+    <ProjectReference Include="..\MockTypeProviders\XmlDocAttributeWithLongComment\XmlDocAttributeWithLongComment.csproj" Private="true" />
+    <ProjectReference Include="..\MockTypeProviders\XmlDocAttributeWithNullComment\XmlDocAttributeWithNullComment.csproj" Private="true" />
+  </ItemGroup>
+
   <ItemGroup>
     <Reference Include="mscorlib" />
     <Reference Include="PresentationCore" />
@@ -190,35 +211,6 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="EnvDTE80" Version="$(EnvDTE80PackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common" Version="$(MicrosoftCodeAnalysisWorkspacesCommonPackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;analyzers;native" />
-    <PackageReference Include="Microsoft.CodeAnalysis.EditorFeatures" Version="$(MicrosoftCodeAnalysisEditorFeaturesPackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;analyzers;native" />
-    <PackageReference Include="Microsoft.CodeAnalysis.EditorFeatures.Text" Version="$(MicrosoftCodeAnalysisEditorFeaturesTextPackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.CoreUtility" Version="$(MicrosoftVisualStudioCoreUtilityPackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Designer.Interfaces" Version="$(MicrosoftVisualStudioDesignerInterfacesPackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Imaging" Version="$(MicrosoftVisualStudioImagingPackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Editor" Version="$(MicrosoftVisualStudioEditorPackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Language" Version="$(MicrosoftVisualStudioLanguagePackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.LanguageServices" Version="$(MicrosoftVisualStudioLanguageServicesPackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.OLE.Interop" Version="$(MicrosoftVisualStudioOLEInteropPackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Shell.15.0" Version="$(MicrosoftVisualStudioShell150PackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Shell.Design" Version="$(MicrosoftVisualStudioShellDesignPackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Shell.Framework" Version="$(MicrosoftVisualStudioShellFrameworkPackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Shell.Immutable.10.0" Version="$(MicrosoftVisualStudioShellImmutable100PackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Shell.Interop" Version="$(MicrosoftVisualStudioShellInteropPackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.8.0" Version="$(MicrosoftVisualStudioShellInterop80PackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.9.0" Version="$(MicrosoftVisualStudioShellInterop90PackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.10.0" Version="$(MicrosoftVisualStudioShellInterop100PackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.11.0" Version="$(MicrosoftVisualStudioShellInterop110PackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.TextManager.Interop.8.0" Version="$(MicrosoftVisualStudioTextManagerInterop80PackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.TextManager.Interop" Version="$(MicrosoftVisualStudioTextManagerInteropPackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Utilities" Version="$(MicrosoftVisualStudioUtilitiesPackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Threading" Version="$(MicrosoftVisualStudioThreadingPackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="Microsoft.VisualStudio.Validation" Version="$(MicrosoftVisualStudioValidationPackageVersion)" PrivateAssets="all" ExcludeAssets="runtime;contentFiles;build;analyzers;native" />
-    <PackageReference Include="NUnit" Version="$(NUnitPackageVersion)" />
-    <PackageReference Include="System.ValueTuple" Version="$(SystemValueTuplePackageVersion)" />
-    <PackageReference Include="VSSDK.VSHelp" Version="$(VSSDKVSHelpPackageVersion)" />
-    <PackageReference Include="VSSDK.VSLangProj.8" Version="$(VSSDKVSLangProj8PackageVersion)" />
     <PackageReference Include="EnvDTE80" Version="$(EnvDTE80PackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;build;analyzers;native" />
     <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common" Version="$(MicrosoftCodeAnalysisWorkspacesCommonPackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;analyzers;native" />
     <PackageReference Include="Microsoft.CodeAnalysis.EditorFeatures" Version="$(MicrosoftCodeAnalysisEditorFeaturesPackageVersion)" PrivateAssets="all" ExcludeAssets="contentFiles;analyzers;native" />