Revised transformation setup

src/QsCompiler/CommandLineTool/Commands/Diagnose.cs

@@ -173,13 +173,13 @@ private static void PrintGeneratedQs(IEnumerable<QsNamespace> evaluatedTree, Com
                 if (Options.IsCodeSnippet(file))
                 {
                     var subtree = evaluatedTree.Select(ns => FilterBySourceFile.Apply(ns, file)).Where(ns => ns.Elements.Any());
-                    var code = new string[] { "" }.Concat(StripSnippetWrapping(subtree).Select(FormatCompilation.FormatStatement));
+                    var code = new string[] { "" }.Concat(StripSnippetWrapping(subtree).Select(SyntaxTreeToQsharp.Default.ToCode));
                     logger.Log(InformationCode.FormattedQsCode, Enumerable.Empty<string>(), messageParam: code.ToArray());
                 }
                 else 
                 {
                     var imports = evaluatedTree.ToImmutableDictionary(ns => ns.Name, ns => compilation.OpenDirectives(file, ns.Name).ToImmutableArray());
-                    SyntaxTreeToQs.Apply(out List<ImmutableDictionary<NonNullable<string>, string>> generated, evaluatedTree, (file, imports));
+                    SyntaxTreeToQsharp.Apply(out List<ImmutableDictionary<NonNullable<string>, string>> generated, evaluatedTree, (file, imports));
                     var code = new string[] { "" }.Concat(generated.Single().Values.Select(nsCode => $"{nsCode}{Environment.NewLine}"));
                     logger.Log(InformationCode.FormattedQsCode, Enumerable.Empty<string>(), file.Value, messageParam: code.ToArray());
                 };

src/QsCompiler/CommandLineTool/Commands/Format.cs

@@ -60,18 +60,6 @@ public static string UpdateArrayLiterals(string fileContent)
         }
 
 
-        /// <summary>
-        /// Returns formatted Q# code for the given statement.
-        /// Throws an ArgumentNullException if the given statement is null.
-        /// </summary>
-        internal static string FormatStatement(QsStatement statement)
-        {
-            if (statement == null) throw new ArgumentNullException(nameof(statement));
-            var ToCode = new ScopeToQs();
-            ToCode.onStatement(statement);
-            return ToCode.Output;
-        }
-
         /// <summary>
         /// Generates formatted Q# code based on the part of the syntax tree that corresponds to each file in the given compilation. 
         /// If the id of a file is consistent with the one assigned to a code snippet,
@@ -85,13 +73,13 @@ private static IEnumerable<string> GenerateQsCode(Compilation compilation, NonNu
             if (Options.IsCodeSnippet(file))
             {
                 var subtree = compilation.SyntaxTree.Values.Select(ns => FilterBySourceFile.Apply(ns, file)).Where(ns => ns.Elements.Any());
-                return DiagnoseCompilation.StripSnippetWrapping(subtree).Select(FormatStatement);
+                return DiagnoseCompilation.StripSnippetWrapping(subtree).Select(SyntaxTreeToQsharp.Default.ToCode);
             }
             else
             {
                 var imports = compilation.SyntaxTree.Values 
                     .ToImmutableDictionary(ns => ns.Name, ns => compilation.OpenDirectives(file, ns.Name).ToImmutableArray());
-                var success = SyntaxTreeToQs.Apply(out List<ImmutableDictionary<NonNullable<string>, string>> generated, compilation.SyntaxTree.Values, (file, imports));
+                var success = SyntaxTreeToQsharp.Apply(out List<ImmutableDictionary<NonNullable<string>, string>> generated, compilation.SyntaxTree.Values, (file, imports));
                 if (!success) logger?.Log(WarningCode.UnresolvedItemsInGeneratedQs, Enumerable.Empty<string>(), file.Value);
 
                 return generated.Single().Select(entry =>

src/QsCompiler/CompilationManager/EditorSupport/CodeActions.cs

@@ -218,11 +218,10 @@ private static IEnumerable<TextEdit> OpenDirectiveSuggestions(this FileContentMa
 
             // update deprecated operation characteristics syntax
 
-            var typeToQs = new ExpressionTypeToQs(new ExpressionToQs());
             string CharacteristicsAnnotation(Characteristics c)
             {
-                typeToQs.onCharacteristicsExpression(SymbolResolution.ResolveCharacteristics(c));
-                return $"{Keywords.qsCharacteristics.id} {typeToQs.Output}";
+                var charEx = SyntaxTreeToQsharp.CharacteristicsExpression(SymbolResolution.ResolveCharacteristics(c));
+                return charEx == null ? "" : $"{Keywords.qsCharacteristics.id} {charEx}";
             }
 
             var suggestionsForOpCharacteristics = deprecatedOpCharacteristics.SelectMany(d =>

src/QsCompiler/CompilationManager/EditorSupport/SymbolInformation.cs

@@ -213,7 +213,7 @@ internal static bool TryGetReferences(
                     .Where(spec => spec.SourceFile.Value == file.FileName.Value)
                     .SelectMany(spec =>
                         spec.Implementation is SpecializationImplementation.Provided impl && spec.Location.IsValue
-                            ? IdentifierLocation.Find(definition.Item.Item1, impl.Item2, file.FileName, spec.Location.Item.Offset)
+                            ? IdentifierReferences.Find(definition.Item.Item1, impl.Item2, file.FileName, spec.Location.Item.Offset)
                             : ImmutableArray<IdentifierReferences.Location>.Empty)
                     .Distinct().Select(AsLocation);
             }
@@ -223,7 +223,7 @@ spec.Implementation is SpecializationImplementation.Provided impl && spec.Locati
                 var statements = implementation.StatementsAfterDeclaration(defStart.Subtract(specPos));
                 var scope = new QsScope(statements.ToImmutableArray(), locals);
                 var rootOffset = DiagnosticTools.AsTuple(specPos); 
-                referenceLocations = IdentifierLocation.Find(definition.Item.Item1, scope, file.FileName, rootOffset).Distinct().Select(AsLocation);
+                referenceLocations = IdentifierReferences.Find(definition.Item.Item1, scope, file.FileName, rootOffset).Distinct().Select(AsLocation);
             }
             declarationLocation = AsLocation(file.FileName, definition.Item.Item2, defRange);
             return true;

src/QsCompiler/Compiler/RewriteSteps/ClassicallyControlled.cs

@@ -5,7 +5,7 @@
 using System.Linq;
 using Microsoft.Quantum.QsCompiler.DataTypes;
 using Microsoft.Quantum.QsCompiler.SyntaxTree;
-using Microsoft.Quantum.QsCompiler.Transformations.ClassicallyControlledTransformation;
+using Microsoft.Quantum.QsCompiler.Transformations.ClassicallyControlled;
 
 
 namespace Microsoft.Quantum.QsCompiler.BuiltInRewriteSteps
@@ -28,7 +28,7 @@ public ClassicallyControlled()
 
         public bool Transformation(QsCompilation compilation, out QsCompilation transformed)
         {
-            transformed = ClassicallyControlledTransformation.Apply(compilation);
+            transformed = ReplaceClassicalControl.Apply(compilation);
             return true;
         }
 

src/QsCompiler/Compiler/RewriteSteps/IntrinsicResolution.cs

@@ -3,7 +3,7 @@
 
 using System.Collections.Generic;
 using Microsoft.Quantum.QsCompiler.SyntaxTree;
-using Microsoft.Quantum.QsCompiler.Transformations.IntrinsicResolutionTransformation;
+using Microsoft.Quantum.QsCompiler.Transformations.IntrinsicResolution;
 
 
 namespace Microsoft.Quantum.QsCompiler.BuiltInRewriteSteps
@@ -35,7 +35,7 @@ public IntrinsicResolution(QsCompilation environment)
 
         public bool Transformation(QsCompilation compilation, out QsCompilation transformed)
         {
-            transformed = IntrinsicResolutionTransformation.Apply(this.Environment, compilation);
+            transformed = ReplaceWithTargetIntrinsics.Apply(this.Environment, compilation);
             return true;
         }
 

src/QsCompiler/Compiler/RewriteSteps/Monomorphization.cs

@@ -5,7 +5,7 @@
 using System.Linq;
 using Microsoft.Quantum.QsCompiler.SyntaxTree;
 using Microsoft.Quantum.QsCompiler.Transformations.Monomorphization;
-using Microsoft.Quantum.QsCompiler.Transformations.MonomorphizationValidation;
+using Microsoft.Quantum.QsCompiler.Transformations.Monomorphization.Validation;
 
 
 namespace Microsoft.Quantum.QsCompiler.BuiltInRewriteSteps
@@ -33,7 +33,7 @@ public Monomorphization()
 
         public bool Transformation(QsCompilation compilation, out QsCompilation transformed)
         {
-            transformed = MonomorphizationTransformation.Apply(compilation);
+            transformed = Monomorphize.Apply(compilation);
             return true;
         }
 
@@ -42,7 +42,7 @@ public bool PreconditionVerification(QsCompilation compilation) =>
 
         public bool PostconditionVerification(QsCompilation compilation)
         {
-            try { MonomorphizationValidationTransformation.Apply(compilation); }
+            try { ValidateMonomorphization.Apply(compilation); }
             catch { return false; }
             return true;
         }

src/QsCompiler/Core/Core.fsproj

@@ -13,13 +13,13 @@
       <Link>DelaySign.fs</Link>
     </Compile>
     <Compile Include="AssemblyInfo.fs" />
-    <Compile Include="ConstructorExtensions.fs" />    
+    <Compile Include="ConstructorExtensions.fs" />
+    <Compile Include="TransformationOptions.fs" />
+    <Compile Include="TypeTransformation.fs" />    
     <Compile Include="ExpressionTransformation.fs" />
     <Compile Include="StatementTransformation.fs" />
-    <Compile Include="TreeTransformation.fs" />
-    <Compile Include="ExpressionWalker.fs" />
-    <Compile Include="StatementWalker.fs" />
-    <Compile Include="TreeWalker.fs" />
+    <Compile Include="NamespaceTransformation.fs" />
+    <Compile Include="SyntaxTreeTransformation.fs" />
     <Compile Include="Dependencies.fs" />
     <Compile Include="SyntaxGenerator.fs" />
     <Compile Include="DeclarationHeaders.fs" />

src/QsCompiler/Core/DeclarationHeaders.fs

@@ -162,7 +162,7 @@ type CallableDeclarationHeader = {
     static member FromJson json =
         let info = {IsMutable = false; HasLocalQuantumDependency = false} 
         let rec setInferredInfo = function // no need to raise an error if anything needs to be set - the info above is always correct
-            | QsTuple ts -> (ts |> Seq.map setInferredInfo).ToImmutableArray() |> QsTuple
+            | QsTuple ts -> ts |> Seq.map setInferredInfo |> ImmutableArray.CreateRange |> QsTuple
             | QsTupleItem (decl : LocalVariableDeclaration<_>) -> QsTupleItem {decl with InferredInformation = info}
         // we need to make sure that all fields that could possibly be null after deserializing 
         // due to changes of fields over time are initialized to a proper value