After installing Visual Studio 2017 15.5 Preview 2, FSharpPackage fails to load

[pkanavos]

This is similar to #2917 and #3040.

I installed 15.5 Preview 2 over an existing VS 2017 Enterprise 15.5 Preview 1 installation and noticed that F# Desktop Language Support was unchecked, although I had installed F#. I added the package. The upgrade finished without errors.

After that, I started getting the same error dialog box as the other issues. ActivityLog.xml contains the same entries:

  <entry>
    <record>1016</record>
    <time>2017/10/24 12:08:40.315</time>
    <type>Information</type>
    <source>VisualStudio</source>
    <description>Begin package load [FSharpPackage]</description>
    <guid>{871D2A70-12A2-4E42-9440-425DD92A4116}</guid>
  </entry>
  <entry>
    <record>1017</record>
    <time>2017/10/24 12:08:40.327</time>
    <type>Error</type>
    <source>VisualStudio</source>
    <description>LegacySitePackage failed for package [FSharpPackage]Source: &apos;Microsoft.VisualStudio.Composition&apos; Description: Expected 1 export(s) with contract name &quot;Microsoft.VisualStudio.FSharp.Editor.SettingsPersistence+ISettings&quot; but found 0 after applying applicable constraints.&#x000D;&#x000A;Microsoft.VisualStudio.Composition.CompositionFailedException: Expected 1 export(s) with contract name &quot;Microsoft.VisualStudio.FSharp.Editor.SettingsPersistence+ISettings&quot; but found 0 after applying applicable constraints.&#x000D;&#x000A;   at Microsoft.VisualStudio.Composition.ExportProvider.GetExports(ImportDefinition importDefinition)&#x000D;&#x000A;   at Microsoft.VisualStudio.Composition.ExportProvider.GetExports[T,TMetadataView](String contractName, ImportCardinality cardinality)&#x000D;&#x000A;   at Microsoft.VisualStudio.Composition.ExportProvider.GetExport[T,TMetadataView](String contractName)&#x000D;&#x000A;   at Microsoft.VisualStudio.Composition.ExportProvider.GetExport[T](String contractName)&#x000D;&#x000A;   at Microsoft.VisualStudio.Composition.ExportProvider.GetExport[T]()&#x000D;&#x000A;   at Microsoft.VisualStudio.Composition.ExportProvider.GetExportedValue[T]()&#x000D;&#x000A;   at Microsoft.VisualStudio.ComponentModelHost.ComponentModel.GetService[T]()&#x000D;&#x000A;   at Microsoft.VisualStudio.FSharp.Editor.FSharpPackage.Initialize()&#x000D;&#x000A;   at Microsoft.VisualStudio.Shell.Package.Microsoft.VisualStudio.Shell.Interop.IVsPackage.SetSite(IServiceProvider sp)</description>
    <guid>{871D2A70-12A2-4E42-9440-425DD92A4116}</guid>
    <hr>80131500</hr>
    <errorinfo></errorinfo>
  </entry>
  <entry>
    <record>1018</record>
    <time>2017/10/24 12:08:40.330</time>
    <type>Error</type>
    <source>VisualStudio</source>
    <description>SetSite failed for package [FSharpPackage](null)</description>
    <guid>{871D2A70-12A2-4E42-9440-425DD92A4116}</guid>
    <hr>80131500</hr>
    <errorinfo></errorinfo>
  </entry>
  <entry>
    <record>1019</record>
    <time>2017/10/24 12:08:40.333</time>
    <type>Error</type>
    <source>VisualStudio</source>
    <description>End package load [FSharpPackage]</description>
    <guid>{871D2A70-12A2-4E42-9440-425DD92A4116}</guid>
    <hr>80131500</hr>
    <errorinfo></errorinfo>
  </entry>
  <entry>
    <record>1020</record>
    <time>2017/10/24 12:08:40.336</time>
    <type>Warning</type>
    <source>VisualStudio</source>
    <description>Package failed to load; error message suppressed by skip flag</description>
    <guid>{871D2A70-12A2-4E42-9440-425DD92A4116}</guid>
  </entry>
  <entry>
    <record>1021</record>
    <time>2017/10/24 12:08:40.336</time>
    <type>Information</type>
    <source>VisualStudio</source>
    <description>Entering function CVsPackageInfo::HrInstantiatePackage</description>
    <guid>{871D2A70-12A2-4E42-9440-425DD92A4116}</guid>
  </entry>
  <entry>
    <record>1022</record>
    <time>2017/10/24 12:08:40.336</time>
    <type>Information</type>
    <source>VisualStudio</source>
    <description>Begin package load [FSharpPackage]</description>
    <guid>{871D2A70-12A2-4E42-9440-425DD92A4116}</guid>
  </entry>
  <entry>
    <record>1023</record>
    <time>2017/10/24 12:08:40.357</time>
    <type>Error</type>
    <source>VisualStudio</source>
    <description>LegacySitePackage failed for package [FSharpPackage]Source: &apos;Microsoft.VisualStudio.Composition&apos; Description: Expected 1 export(s) with contract name &quot;Microsoft.VisualStudio.FSharp.Editor.SettingsPersistence+ISettings&quot; but found 0 after applying applicable constraints.&#x000D;&#x000A;Microsoft.VisualStudio.Composition.CompositionFailedException: Expected 1 export(s) with contract name &quot;Microsoft.VisualStudio.FSharp.Editor.SettingsPersistence+ISettings&quot; but found 0 after applying applicable constraints.&#x000D;&#x000A;   at Microsoft.VisualStudio.Composition.ExportProvider.GetExports(ImportDefinition importDefinition)&#x000D;&#x000A;   at Microsoft.VisualStudio.Composition.ExportProvider.GetExports[T,TMetadataView](String contractName, ImportCardinality cardinality)&#x000D;&#x000A;   at Microsoft.VisualStudio.Composition.ExportProvider.GetExport[T,TMetadataView](String contractName)&#x000D;&#x000A;   at Microsoft.VisualStudio.Composition.ExportProvider.GetExport[T](String contractName)&#x000D;&#x000A;   at Microsoft.VisualStudio.Composition.ExportProvider.GetExport[T]()&#x000D;&#x000A;   at Microsoft.VisualStudio.Composition.ExportProvider.GetExportedValue[T]()&#x000D;&#x000A;   at Microsoft.VisualStudio.ComponentModelHost.ComponentModel.GetService[T]()&#x000D;&#x000A;   at Microsoft.VisualStudio.FSharp.Editor.FSharpPackage.Initialize()&#x000D;&#x000A;   at Microsoft.VisualStudio.Shell.Package.Microsoft.VisualStudio.Shell.Interop.IVsPackage.SetSite(IServiceProvider sp)</description>
    <guid>{871D2A70-12A2-4E42-9440-425DD92A4116}</guid>
    <hr>80131500</hr>
    <errorinfo></errorinfo>
  </entry>
  <entry>
    <record>1024</record>
    <time>2017/10/24 12:08:40.361</time>
    <type>Error</type>
    <source>VisualStudio</source>
    <description>SetSite failed for package [FSharpPackage](null)</description>
    <guid>{871D2A70-12A2-4E42-9440-425DD92A4116}</guid>
    <hr>80131500</hr>
    <errorinfo></errorinfo>
  </entry>

My F# projects load and build, but therere is no syntax highlighting and the Enter key doesn't work on F# files.

The same error appeared for a time whenever I loaded a solution that contained F# projects. After restarting Visual Studio 2-3 times the error dialog box disappeared but the editor still doesn't work.

Uninstalling and reinstalling the F# package didn't help. The same error dialog box started appearing again.

The problem does not occur in a 15.5 Preview 1 Community edition I have installed side-by-side. The F# package is installed and called F# Language support. The same projects open and build without problems. The version of F# tools installed in this installation has 15.4.1.170929605.

Update

I was able to solve this by removing the 15.5.2 package and installing the latest nightly build, 15.4.1.17102302

[cartermp]

This is actually the same root cause as #3799, which has been fixed by #3804.

Basically, VS will either fail to load the desktop templates or the entire F# setup package, depending on which .vsixmanifest file gets read first. This is because of a setup error on our part, which is now fixed.

As you've noticed this is indeed fixed in the nightly channel, and it'll be available in the next preview release of 15.5.