Remove syntax annotations from the Razor compiler

Here's the thing: the Razor compiler doesn't need syntax annotations. Originally, annotations were added to Roslyn to support the IDE when making tree transformations. However, Razor tooling doesn't actually perform any tree transformations. So, tooling doesn't use annotations. The problem is that the compiler *does* use annotations to stuff data onto syntax nodes -- data that should have been part of the syntax model in the first place.

Now that all compiler data has been moved into the syntax model, syntax annotations are pure overhead and can be removed.

Author: DustinCampbell

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperBlockRewriter.cs

@@ -638,8 +638,6 @@ public override SyntaxNode VisitCSharpImplicitExpression(CSharpImplicitExpressio
                 var firstToken = firstChild.GetFirstToken();
                 var newFirstToken = SyntaxFactory.Token(firstToken.Kind, node.Transition.Transition.Content + firstToken.Content);
 
-                firstToken.CopyAnnotationsTo(newFirstToken);
-
                 var newFirstChild = firstChild.ReplaceToken(firstToken, newFirstToken);
                 builder.AddRange(rewrittenBody.Children.Replace(firstChild, newFirstChild));
 

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Syntax/Generated/Syntax.xml.Internal.Generated.cs

@@ -11,10 +11,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Syntax;
 [DebuggerDisplay("{GetDebuggerDisplay(), nq}")]
 internal abstract partial class GreenNode
 {
-    private static readonly RazorDiagnostic[] EmptyDiagnostics = [];
-    private static readonly SyntaxAnnotation[] EmptyAnnotations = [];
-    private static readonly ConditionalWeakTable<GreenNode, RazorDiagnostic[]> DiagnosticsTable = new();
-    private static readonly ConditionalWeakTable<GreenNode, SyntaxAnnotation[]> AnnotationsTable = new();
+    private static readonly ConditionalWeakTable<GreenNode, RazorDiagnostic[]> s_diagnosticsTable = new();
+    private static readonly RazorDiagnostic[] s_emptyDiagnostics = [];
 
     private int _width;
     private byte _slotCount;
@@ -30,32 +28,18 @@ protected GreenNode(SyntaxKind kind, int width)
         _width = width;
     }
 
-    protected GreenNode(SyntaxKind kind, RazorDiagnostic[]? diagnostics, SyntaxAnnotation[]? annotations)
-        : this(kind, 0, diagnostics, annotations)
+    protected GreenNode(SyntaxKind kind, RazorDiagnostic[]? diagnostics)
+        : this(kind, 0, diagnostics)
     {
     }
 
-    protected GreenNode(SyntaxKind kind, int width, RazorDiagnostic[]? diagnostics, SyntaxAnnotation[]? annotations)
+    protected GreenNode(SyntaxKind kind, int width, RazorDiagnostic[]? diagnostics)
         : this(kind, width)
     {
         if (diagnostics?.Length > 0)
         {
             Flags |= NodeFlags.ContainsDiagnostics;
-            DiagnosticsTable.Add(this, diagnostics);
-        }
-
-        if (annotations?.Length > 0)
-        {
-            foreach (var annotation in annotations)
-            {
-                if (annotation == null)
-                {
-                    throw new ArgumentException("Annotation cannot be null", nameof(annotations));
-                }
-            }
-
-            Flags |= NodeFlags.ContainsAnnotations;
-            AnnotationsTable.Add(this, annotations);
+            s_diagnosticsTable.Add(this, diagnostics);
         }
     }
 
@@ -171,8 +155,6 @@ internal void ClearFlags(NodeFlags flags)
     internal virtual bool IsMissing => (Flags & NodeFlags.IsMissing) != 0;
 
     public bool ContainsDiagnostics => (Flags & NodeFlags.ContainsDiagnostics) != 0;
-
-    public bool ContainsAnnotations => (Flags & NodeFlags.ContainsAnnotations) != 0;
     #endregion
 
     #region Diagnostics
@@ -182,31 +164,13 @@ internal RazorDiagnostic[] GetDiagnostics()
     {
         if (ContainsDiagnostics)
         {
-            if (DiagnosticsTable.TryGetValue(this, out var diagnostics))
+            if (s_diagnosticsTable.TryGetValue(this, out var diagnostics))
             {
                 return diagnostics;
             }
         }
 
-        return EmptyDiagnostics;
-    }
-    #endregion
-
-    #region Annotations
-    internal abstract GreenNode SetAnnotations(SyntaxAnnotation[]? annotations);
-
-    internal SyntaxAnnotation[] GetAnnotations()
-    {
-        if (ContainsAnnotations)
-        {
-            if (AnnotationsTable.TryGetValue(this, out var annotations))
-            {
-                Debug.Assert(annotations.Length != 0, "There cannot be an empty annotation entry.");
-                return annotations;
-            }
-        }
-
-        return EmptyAnnotations;
+        return s_emptyDiagnostics;
     }
     #endregion
 

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Syntax/Generated/Syntax.xml.Syntax.Generated.cs

@@ -5,7 +5,6 @@
 
 using System.Collections.Immutable;
 using System.Runtime.InteropServices;
-using Microsoft.AspNetCore.Razor.PooledObjects;
 
 namespace Microsoft.AspNetCore.Razor.Language.Syntax;
 
@@ -23,31 +22,6 @@ internal static InternalSyntax.SyntaxList<T> ToGreenList<T>(this GreenNode node)
         return new InternalSyntax.SyntaxList<T>(node);
     }
 
-    public static TNode WithAnnotationsGreen<TNode>(this TNode node, params SyntaxAnnotation[] annotations) where TNode : GreenNode
-    {
-        if (annotations.Length == 0)
-        {
-            var existingAnnotations = node.GetAnnotations();
-            if (existingAnnotations != null && existingAnnotations.Length > 0)
-            {
-                node = (TNode)node.SetAnnotations(null);
-            }
-
-            return node;
-        }
-
-        using var newAnnotations = new PooledArrayBuilder<SyntaxAnnotation>(annotations.Length);
-        foreach (var candidate in annotations)
-        {
-            if (!newAnnotations.Contains(candidate))
-            {
-                newAnnotations.Add(candidate);
-            }
-        }
-
-        return (TNode)node.SetAnnotations(newAnnotations.ToArray());
-    }
-
     public static TNode WithDiagnosticsGreen<TNode>(this TNode node, RazorDiagnostic[] diagnostics)
         where TNode : GreenNode
     {

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Syntax/GreenNode.cs

@@ -16,13 +16,13 @@ protected RazorSyntaxNode(SyntaxKind kind, int width)
     {
     }
 
-    protected RazorSyntaxNode(SyntaxKind kind, RazorDiagnostic[] diagnostics, SyntaxAnnotation[] annotations)
-        : base(kind, diagnostics, annotations)
+    protected RazorSyntaxNode(SyntaxKind kind, RazorDiagnostic[] diagnostics)
+        : base(kind, diagnostics)
     {
     }
 
-    protected RazorSyntaxNode(SyntaxKind kind, int width, RazorDiagnostic[] diagnostics, SyntaxAnnotation[] annotations)
-        : base(kind, width, diagnostics, annotations)
+    protected RazorSyntaxNode(SyntaxKind kind, int width, RazorDiagnostic[] diagnostics)
+        : base(kind, width, diagnostics)
     {
     }
 }

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Syntax/GreenNodeExtensions.cs

@@ -15,8 +15,8 @@ internal SyntaxList()
     {
     }
 
-    internal SyntaxList(RazorDiagnostic[] diagnostics, SyntaxAnnotation[] annotations)
-        : base(SyntaxKind.List, diagnostics, annotations)
+    internal SyntaxList(RazorDiagnostic[] diagnostics)
+        : base(SyntaxKind.List, diagnostics)
     {
     }
 
@@ -72,7 +72,7 @@ internal static WithThreeChildren List(GreenNode child0, GreenNode child1, Green
     }
 
     internal static GreenNode List<TNode>(ReadOnlySpan<TNode> nodes)
-    where TNode : GreenNode
+        where TNode : GreenNode
     {
         var count = nodes.Length;
         var array = new ArrayElement<GreenNode>[count];
@@ -184,7 +184,8 @@ internal WithTwoChildren(GreenNode child0, GreenNode child1)
             _child1 = child1;
         }
 
-        internal WithTwoChildren(RazorDiagnostic[] diagnostics, SyntaxAnnotation[] annotations, GreenNode child0, GreenNode child1)
+        internal WithTwoChildren(GreenNode child0, GreenNode child1, RazorDiagnostic[] diagnostics)
+            : base(diagnostics)
         {
             SlotCount = 2;
             AdjustFlagsAndWidth(child0);
@@ -219,12 +220,7 @@ internal override SyntaxNode CreateRed(SyntaxNode parent, int position)
 
         internal override GreenNode SetDiagnostics(RazorDiagnostic[] errors)
         {
-            return new WithTwoChildren(errors, this.GetAnnotations(), _child0, _child1);
-        }
-
-        internal override GreenNode SetAnnotations(SyntaxAnnotation[] annotations)
-        {
-            return new WithTwoChildren(GetDiagnostics(), annotations, _child0, _child1);
+            return new WithTwoChildren(_child0, _child1, errors);
         }
     }
 
@@ -245,8 +241,8 @@ internal WithThreeChildren(GreenNode child0, GreenNode child1, GreenNode child2)
             _child2 = child2;
         }
 
-        internal WithThreeChildren(RazorDiagnostic[] diagnostics, SyntaxAnnotation[] annotations, GreenNode child0, GreenNode child1, GreenNode child2)
-            : base(diagnostics, annotations)
+        internal WithThreeChildren(GreenNode child0, GreenNode child1, GreenNode child2, RazorDiagnostic[] diagnostics)
+            : base(diagnostics)
         {
             SlotCount = 3;
             AdjustFlagsAndWidth(child0);
@@ -286,12 +282,7 @@ internal override SyntaxNode CreateRed(SyntaxNode parent, int position)
 
         internal override GreenNode SetDiagnostics(RazorDiagnostic[] errors)
         {
-            return new WithThreeChildren(errors, GetAnnotations(), _child0, _child1, _child2);
-        }
-
-        internal override GreenNode SetAnnotations(SyntaxAnnotation[] annotations)
-        {
-            return new WithThreeChildren(GetDiagnostics(), annotations, _child0, _child1, _child2);
+            return new WithThreeChildren(_child0, _child1, _child2, errors);
         }
     }
 
@@ -305,8 +296,8 @@ internal WithManyChildrenBase(ArrayElement<GreenNode>[] children)
             this.InitializeChildren();
         }
 
-        internal WithManyChildrenBase(RazorDiagnostic[] diagnostics, SyntaxAnnotation[] annotations, ArrayElement<GreenNode>[] children)
-            : base(diagnostics, annotations)
+        internal WithManyChildrenBase(ArrayElement<GreenNode>[] children, RazorDiagnostic[] diagnostics)
+            : base(diagnostics)
         {
             this.children = children;
             this.InitializeChildren();
@@ -358,19 +349,14 @@ internal WithManyChildren(ArrayElement<GreenNode>[] children)
         {
         }
 
-        internal WithManyChildren(RazorDiagnostic[] diagnostics, SyntaxAnnotation[] annotations, ArrayElement<GreenNode>[] children)
-            : base(diagnostics, annotations, children)
+        internal WithManyChildren(ArrayElement<GreenNode>[] children, RazorDiagnostic[] diagnostics)
+            : base(children, diagnostics)
         {
         }
 
         internal override GreenNode SetDiagnostics(RazorDiagnostic[] errors)
         {
-            return new WithManyChildren(errors, GetAnnotations(), children);
-        }
-
-        internal override GreenNode SetAnnotations(SyntaxAnnotation[] annotations)
-        {
-            return new WithManyChildren(GetDiagnostics(), annotations, children);
+            return new WithManyChildren(children, errors);
         }
     }
 
@@ -384,8 +370,8 @@ internal WithLotsOfChildren(ArrayElement<GreenNode>[] children)
             _childOffsets = CalculateOffsets(children);
         }
 
-        internal WithLotsOfChildren(RazorDiagnostic[] diagnostics, SyntaxAnnotation[] annotations, ArrayElement<GreenNode>[] children, int[] childOffsets)
-            : base(diagnostics, annotations, children)
+        internal WithLotsOfChildren(ArrayElement<GreenNode>[] children, int[] childOffsets, RazorDiagnostic[] diagnostics)
+            : base(children, diagnostics)
         {
             _childOffsets = childOffsets;
         }
@@ -425,12 +411,7 @@ private static int[] CalculateOffsets(ArrayElement<GreenNode>[] children)
 
         internal override GreenNode SetDiagnostics(RazorDiagnostic[] errors)
         {
-            return new WithLotsOfChildren(errors, this.GetAnnotations(), children, _childOffsets);
-        }
-
-        internal override GreenNode SetAnnotations(SyntaxAnnotation[] annotations)
-        {
-            return new WithLotsOfChildren(GetDiagnostics(), annotations, children, _childOffsets);
+            return new WithLotsOfChildren(children, _childOffsets, errors);
         }
 
         /// <summary>

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Syntax/InternalSyntax/RazorSyntaxNode.cs

@@ -10,9 +10,8 @@ internal class SyntaxToken : RazorSyntaxNode
     internal SyntaxToken(
         SyntaxKind kind,
         string content,
-        RazorDiagnostic[]? diagnostics,
-        SyntaxAnnotation[]? annotations = null)
-        : base(kind, content.Length, diagnostics, annotations)
+        RazorDiagnostic[]? diagnostics)
+        : base(kind, content.Length, diagnostics)
     {
         Content = content;
     }
@@ -28,12 +27,7 @@ internal override SyntaxNode CreateRed(SyntaxNode? parent, int position)
 
     internal override GreenNode SetDiagnostics(RazorDiagnostic[]? diagnostics)
     {
-        return new SyntaxToken(Kind, Content, diagnostics, GetAnnotations());
-    }
-
-    internal override GreenNode SetAnnotations(SyntaxAnnotation[]? annotations)
-    {
-        return new SyntaxToken(Kind, Content, GetDiagnostics(), annotations);
+        return new SyntaxToken(Kind, Content, diagnostics);
     }
 
     protected sealed override int GetSlotCount()

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Syntax/InternalSyntax/SyntaxList.cs

@@ -10,8 +10,7 @@ internal enum NodeFlags : byte
 {
     None = 0,
     ContainsDiagnostics = 1 << 0,
-    ContainsAnnotations = 1 << 1,
     IsMissing = 1 << 2,
 
-    InheritMask = ContainsDiagnostics | ContainsAnnotations | IsMissing
+    InheritMask = ContainsDiagnostics | IsMissing
 }