Get rid of Parent from IR node

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/InjectDirective.cs

@@ -59,7 +59,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
                     {
                         TypeName = typeName,
                         MemberName = memberName,
-                        Parent = visitor.Class,
                     };
 
                     visitor.Class.Children.Add(injectNode);

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/InjectDirectiveIRNode.cs

@@ -16,8 +16,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
 
         public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public override void Accept(RazorIRNodeVisitor visitor)

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/InstrumentationPass.cs

@@ -30,10 +30,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             var beginContextMethodName = "BeginContext"; /* ORIGINAL: BeginContextMethodName */
             var endContextMethodName = "EndContext"; /* ORIGINAL: EndContextMethodName */
 
-            var beginNode = new CSharpCodeIRNode()
+            var beginNode = new CSharpCodeIRNode();
-            {
-                Parent = item.Node.Parent
-            };
             RazorIRBuilder.Create(beginNode)
                 .Add(new RazorIRToken()
                 {
@@ -45,10 +42,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
                         item.IsLiteral ? "true" : "false")
                 });
 
-            var endNode = new CSharpCodeIRNode()
+            var endNode = new CSharpCodeIRNode();
-            {
-                Parent = item.Node.Parent
-            };
             RazorIRBuilder.Create(endNode)
                 .Add(new RazorIRToken()
                 {
@@ -56,22 +50,25 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
                     Content = string.Format("{0}();", endContextMethodName)
                 });
 
-            var nodeIndex = item.Node.Parent.Children.IndexOf(item.Node);
+            var nodeIndex = item.Parent.Children.IndexOf(item.Node);
-            item.Node.Parent.Children.Insert(nodeIndex, beginNode);
+            item.Parent.Children.Insert(nodeIndex, beginNode);
-            item.Node.Parent.Children.Insert(nodeIndex + 2, endNode);
+            item.Parent.Children.Insert(nodeIndex + 2, endNode);
         }
 
         private struct InstrumentationItem
         {
-            public InstrumentationItem(RazorIRNode node, bool isLiteral, SourceSpan source)
+            public InstrumentationItem(RazorIRNode node, RazorIRNode parent, bool isLiteral, SourceSpan source)
             {
                 Node = node;
+                Parent = parent;
                 IsLiteral = isLiteral;
                 Source = source;
             }
 
             public RazorIRNode Node { get; }
 
+            public RazorIRNode Parent { get; }
+
             public bool IsLiteral { get; }
 
             public SourceSpan Source { get; }
@@ -85,7 +82,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             {
                 if (node.Source != null)
                 {
-                    Items.Add(new InstrumentationItem(node, isLiteral: true, source: node.Source.Value));
+                    Items.Add(new InstrumentationItem(node, Parent, isLiteral: true, source: node.Source.Value));
                 }
 
                 VisitDefault(node);
@@ -95,7 +92,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             {
                 if (node.Source != null)
                 {
-                    Items.Add(new InstrumentationItem(node, isLiteral: false, source: node.Source.Value));
+                    Items.Add(new InstrumentationItem(node, Parent, isLiteral: false, source: node.Source.Value));
                 }
 
                 VisitDefault(node);
@@ -105,7 +102,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             {
                 if (node.Source != null)
                 {
-                    Items.Add(new InstrumentationItem(node, isLiteral: false, source: node.Source.Value));
+                    Items.Add(new InstrumentationItem(node, Parent, isLiteral: false, source: node.Source.Value));
                 }
 
                 VisitDefault(node);

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/ModelExpressionPass.cs

@@ -79,7 +79,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
                     node.Children.Clear();
 
                     node.Children.Add(expression);
-                    expression.Parent = node;
                 }
             }
         }

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/PagesPropertyInjectionPass.cs

@@ -22,10 +22,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             var @class = visitor.Class;
 
             var viewDataType = $"global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewDataDictionary<{modelType}>";
-            var vddProperty = new CSharpCodeIRNode()
+            var vddProperty = new CSharpCodeIRNode();
-            {
-                Parent = @class
-            };
             RazorIRBuilder.Create(vddProperty)
                 .Add(new RazorIRToken()
                 {
@@ -34,10 +31,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
                 });
             @class.Children.Add(vddProperty);
 
-            var modelProperty = new CSharpCodeIRNode()
+            var modelProperty = new CSharpCodeIRNode();
-            {
-                Parent = @class
-            };
             RazorIRBuilder.Create(modelProperty)
                 .Add(new RazorIRToken()
                 {

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/ViewComponentTagHelperPass.cs

@@ -37,9 +37,9 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
                 }
             }
 
-            foreach (var createNode in visitor.CreateTagHelpers)
+            foreach (var (node, parent) in visitor.CreateTagHelpers)
             {
-                RewriteCreateNode(visitor.Namespace, visitor.Class, createNode);
+                RewriteCreateNode(visitor.Namespace, visitor.Class, node, parent);
             }
         }
 
@@ -48,10 +48,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             var writer = new CSharpCodeWriter();
             WriteClass(writer, tagHelper);
 
-            var statement = new CSharpCodeIRNode()
+            var statement = new CSharpCodeIRNode();
-            {
-                Parent = @class
-            };
             RazorIRBuilder.Create(statement)
                 .Add(new RazorIRToken()
                 {
@@ -65,12 +62,13 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
         private void RewriteCreateNode(
             NamespaceDeclarationIRNode @namespace,
             ClassDeclarationIRNode @class,
-            CreateTagHelperIRNode node)
+            CreateTagHelperIRNode node,
+            RazorIRNode parent)
         {
             var newTypeName = GetVCTHFullName(@namespace, @class, node.Descriptor);
-            for (var i = 0; i < node.Parent.Children.Count; i++)
+            for (var i = 0; i < parent.Children.Count; i++)
             {
-                if (node.Parent.Children[i] is SetTagHelperPropertyIRNode setProperty &&
+                if (parent.Children[i] is SetTagHelperPropertyIRNode setProperty &&
                     node.Descriptor.BoundAttributes.Contains(setProperty.Descriptor))
                 {
                     setProperty.TagHelperTypeName = newTypeName;
@@ -232,7 +230,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
 
             public NamespaceDeclarationIRNode Namespace { get; private set; }
 
-            public List<CreateTagHelperIRNode> CreateTagHelpers { get; } = new List<CreateTagHelperIRNode>();
+            public List<(CreateTagHelperIRNode node, RazorIRNode parent)> CreateTagHelpers { get; } = new List<(CreateTagHelperIRNode node, RazorIRNode parent)>();
 
             public Dictionary<string, TagHelperDescriptor> TagHelpers { get; } = new Dictionary<string, TagHelperDescriptor>();
 
@@ -245,7 +243,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
                     var vcName = tagHelper.Metadata[ViewComponentTagHelperDescriptorConventions.ViewComponentNameKey];
                     TagHelpers[vcName] = tagHelper;
 
-                    CreateTagHelpers.Add(node);
+                    CreateTagHelpers.Add((node, Parent));
                 }
             }
 

src/Microsoft.AspNetCore.Razor.Language/CodeGeneration/DesignTimeTagHelperWriter.cs

@@ -136,14 +136,26 @@ namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration
 
         private void RenderTagHelperAttributeInline(
             CSharpRenderingContext context,
+            SetTagHelperPropertyIRNode property,
+            SourceSpan documentLocation)
+        {
+            for (var i = 0; i < property.Children.Count; i++)
+            {
+                RenderTagHelperAttributeInline(context, property, property.Children[i], documentLocation);
+            }
+        }
+
+        private void RenderTagHelperAttributeInline(
+            CSharpRenderingContext context,
+            SetTagHelperPropertyIRNode property,
             RazorIRNode node,
             SourceSpan documentLocation)
         {
-            if (node is SetTagHelperPropertyIRNode || node is CSharpExpressionIRNode || node is HtmlContentIRNode)
+            if (node is CSharpExpressionIRNode || node is HtmlContentIRNode)
             {
                 for (var i = 0; i < node.Children.Count; i++)
                 {
-                    RenderTagHelperAttributeInline(context, node.Children[i], documentLocation);
+                    RenderTagHelperAttributeInline(context, property, node.Children[i], documentLocation);
                 }
             }
             else if (node is RazorIRToken token)
@@ -165,9 +177,9 @@ namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration
             }
             else if (node is TemplateIRNode)
             {
-                var attributeValueNode = (SetTagHelperPropertyIRNode)node.Parent;
+                var expectedTypeName = property.IsIndexerNameMatch ? property.Descriptor.IndexerTypeName : property.Descriptor.TypeName;
                 var error = new RazorError(
-                    LegacyResources.FormatTagHelpers_InlineMarkupBlocks_NotSupported_InAttributes(attributeValueNode.Descriptor.TypeName),
+                    LegacyResources.FormatTagHelpers_InlineMarkupBlocks_NotSupported_InAttributes(expectedTypeName),
                     new SourceLocation(documentLocation.AbsoluteIndex, documentLocation.CharacterIndex, documentLocation.Length),
                     documentLocation.Length);
                 context.Diagnostics.Add(RazorDiagnostic.Create(error));

src/Microsoft.AspNetCore.Razor.Language/CodeGeneration/RuntimeTagHelperWriter.cs

@@ -421,14 +421,26 @@ namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration
 
         private void RenderTagHelperAttributeInline(
             CSharpRenderingContext context,
+            SetTagHelperPropertyIRNode property,
+            SourceSpan documentLocation)
+        {
+            for (var i = 0; i < property.Children.Count; i++)
+            {
+                RenderTagHelperAttributeInline(context, property, property.Children[i], documentLocation);
+            }
+        }
+
+        private void RenderTagHelperAttributeInline(
+            CSharpRenderingContext context,
+            SetTagHelperPropertyIRNode property,
             RazorIRNode node,
             SourceSpan documentLocation)
         {
-            if (node is SetTagHelperPropertyIRNode || node is CSharpExpressionIRNode || node is HtmlContentIRNode)
+            if (node is CSharpExpressionIRNode || node is HtmlContentIRNode)
             {
                 for (var i = 0; i < node.Children.Count; i++)
                 {
-                    RenderTagHelperAttributeInline(context, node.Children[i], documentLocation);
+                    RenderTagHelperAttributeInline(context, property, node.Children[i], documentLocation);
                 }
             }
             else if (node is RazorIRToken token)
@@ -445,10 +457,7 @@ namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration
             }
             else if (node is TemplateIRNode)
             {
-                var attributeValueNode = (SetTagHelperPropertyIRNode)node.Parent;
+                var expectedTypeName = property.IsIndexerNameMatch ? property.Descriptor.IndexerTypeName : property.Descriptor.TypeName;
-                var expectedTypeName = attributeValueNode.IsIndexerNameMatch ?
-                    attributeValueNode.Descriptor.IndexerTypeName :
-                    attributeValueNode.Descriptor.TypeName;
                 var error = new RazorError(
                     LegacyResources.FormatTagHelpers_InlineMarkupBlocks_NotSupported_InAttributes(expectedTypeName),
                     new SourceLocation(documentLocation.AbsoluteIndex, documentLocation.CharacterIndex, documentLocation.Length),

src/Microsoft.AspNetCore.Razor.Language/DefaultDirectiveIRPass.cs

@@ -20,20 +20,19 @@ namespace Microsoft.AspNetCore.Razor.Language
             walker.VisitDocument(irDocument);
 
             var classNode = walker.ClassNode;
-            foreach (var node in walker.FunctionsDirectiveNodes)
+            foreach (var (node, parent) in walker.FunctionsDirectiveNodes)
             {
-                node.Parent.Children.Remove(node);
+                parent.Children.Remove(node);
 
                 foreach (var child in node.Children.Except(node.Tokens))
                 {
-                    child.Parent = classNode;
                     classNode.Children.Add(child);
                 }
             }
 
-            foreach (var node in walker.InheritsDirectiveNodes.Reverse())
+            foreach (var (node, parent) in walker.InheritsDirectiveNodes.Reverse())
             {
-                node.Parent.Children.Remove(node);
+                parent.Children.Remove(node);
 
                 var token = node.Tokens.FirstOrDefault();
                 if (token != null)
@@ -43,10 +42,10 @@ namespace Microsoft.AspNetCore.Razor.Language
                 }
             }
 
-            foreach (var node in walker.SectionDirectiveNodes)
+            foreach (var (node, parent) in walker.SectionDirectiveNodes)
             {
-                var sectionIndex = node.Parent.Children.IndexOf(node);
+                var sectionIndex = parent.Children.IndexOf(node);
-                node.Parent.Children.Remove(node);
+                parent.Children.Remove(node);
 
                 var defineSectionEndStatement = new CSharpCodeIRNode();
                 RazorIRBuilder.Create(defineSectionEndStatement)
@@ -56,11 +55,11 @@ namespace Microsoft.AspNetCore.Razor.Language
                         Content = "});"
                     });
 
-                node.Parent.Children.Insert(sectionIndex, defineSectionEndStatement);
+                parent.Children.Insert(sectionIndex, defineSectionEndStatement);
 
                 foreach (var child in node.Children.Except(node.Tokens).Reverse())
                 {
-                    node.Parent.Children.Insert(sectionIndex, child);
+                    parent.Children.Insert(sectionIndex, child);
                 }
 
                 var lambdaContent = designTime ? "__razor_section_writer" : string.Empty;
@@ -73,7 +72,7 @@ namespace Microsoft.AspNetCore.Razor.Language
                         Content = $"DefineSection(\"{sectionName}\", async ({lambdaContent}) => {{"
                     });
 
-                node.Parent.Children.Insert(sectionIndex, defineSectionStartStatement);
+                parent.Children.Insert(sectionIndex, defineSectionStartStatement);
             }
         }
 
@@ -81,11 +80,11 @@ namespace Microsoft.AspNetCore.Razor.Language
         {
             public ClassDeclarationIRNode ClassNode { get; private set; }
 
-            public IList<DirectiveIRNode> FunctionsDirectiveNodes { get; } = new List<DirectiveIRNode>();
+            public IList<(DirectiveIRNode node, RazorIRNode parent)> FunctionsDirectiveNodes { get; } = new List<(DirectiveIRNode node, RazorIRNode parent)>();
 
-            public IList<DirectiveIRNode> InheritsDirectiveNodes { get; } = new List<DirectiveIRNode>();
+            public IList<(DirectiveIRNode node, RazorIRNode parent)> InheritsDirectiveNodes { get; } = new List<(DirectiveIRNode node, RazorIRNode parent)>();
 
-            public IList<DirectiveIRNode> SectionDirectiveNodes { get; } = new List<DirectiveIRNode>();
+            public IList<(DirectiveIRNode node, RazorIRNode parent)> SectionDirectiveNodes { get; } = new List<(DirectiveIRNode node, RazorIRNode parent)>();
 
             public override void VisitClassDeclaration(ClassDeclarationIRNode node)
             {
@@ -101,15 +100,15 @@ namespace Microsoft.AspNetCore.Razor.Language
             {
                 if (string.Equals(node.Name, CSharpCodeParser.FunctionsDirectiveDescriptor.Directive, StringComparison.Ordinal))
                 {
-                    FunctionsDirectiveNodes.Add(node);
+                    FunctionsDirectiveNodes.Add((node, Parent));
                 }
                 else if (string.Equals(node.Name, CSharpCodeParser.InheritsDirectiveDescriptor.Directive, StringComparison.Ordinal))
                 {
-                    InheritsDirectiveNodes.Add(node);
+                    InheritsDirectiveNodes.Add((node, Parent));
                 }
                 else if (string.Equals(node.Name, CSharpCodeParser.SectionDirectiveDescriptor.Directive, StringComparison.Ordinal))
                 {
-                    SectionDirectiveNodes.Add(node);
+                    SectionDirectiveNodes.Add((node, Parent));
                 }
             }
         }

src/Microsoft.AspNetCore.Razor.Language/DefaultRazorIRLoweringPhase.cs

@@ -551,7 +551,6 @@ namespace Microsoft.AspNetCore.Razor.Language
                     Content = span.Content,
                     Kind = RazorIRToken.TokenKind.Html,
                     Source = BuildSourceSpanFromNode(span),
-                    Parent = node
                 });
 
                 if (node.Source != null)
@@ -571,7 +570,7 @@ namespace Microsoft.AspNetCore.Razor.Language
             {
                 if (_tagHelperFields == null)
                 {
-                    _tagHelperFields = new DeclareTagHelperFieldsIRNode() { Parent = _document, };
+                    _tagHelperFields = new DeclareTagHelperFieldsIRNode();
                     _document.Children.Add(_tagHelperFields);
                 }
 

src/Microsoft.AspNetCore.Razor.Language/DirectiveRemovalIROptimizationPass.cs

@@ -15,19 +15,19 @@ namespace Microsoft.AspNetCore.Razor.Language
             var visitor = new Visitor();
             visitor.VisitDocument(irDocument);
 
-            foreach (var node in visitor.DirectiveNodes)
+            foreach (var (node, parent) in visitor.DirectiveNodes)
             {
-                node.Parent.Children.Remove(node);
+                parent.Children.Remove(node);
             }
         }
 
         private class Visitor : RazorIRNodeWalker
         {
-            public IList<DirectiveIRNode> DirectiveNodes { get; } = new List<DirectiveIRNode>();
+            public IList<(DirectiveIRNode node, RazorIRNode parent)> DirectiveNodes { get; } = new List<(DirectiveIRNode node, RazorIRNode parent)>();
 
             public override void VisitDirective(DirectiveIRNode node)
             {
-                DirectiveNodes.Add(node);
+                DirectiveNodes.Add((node, Parent));
             }
         }
     }

src/Microsoft.AspNetCore.Razor.Language/Extensions/TemplateIRNode.cs

@@ -10,9 +10,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
     public sealed class TemplateIRNode : ExtensionIRNode
     {
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
-
+        
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public override void Accept(RazorIRNodeVisitor visitor)

src/Microsoft.AspNetCore.Razor.Language/Intermediate/AddPreallocatedTagHelperHtmlAttributeIRNode.cs

@@ -10,8 +10,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
     {
         public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string VariableName { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/AddTagHelperHtmlAttributeIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 using Microsoft.AspNetCore.Razor.Language.Legacy;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
@@ -13,8 +12,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string Name { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/CSharpCodeAttributeValueIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
@@ -12,8 +11,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string Prefix { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/CSharpCodeIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
@@ -25,8 +24,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public override void Accept(RazorIRNodeVisitor visitor)

src/Microsoft.AspNetCore.Razor.Language/Intermediate/CSharpExpressionAttributeValueIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
@@ -12,8 +11,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string Prefix { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/CSharpExpressionIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
@@ -25,8 +24,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public override void Accept(RazorIRNodeVisitor visitor)

src/Microsoft.AspNetCore.Razor.Language/Intermediate/ChecksumIRNode.cs

@@ -11,8 +11,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string Bytes { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/ClassDeclarationIRNode.cs

@@ -25,8 +25,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string AccessModifier { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/CreateTagHelperIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
@@ -12,8 +11,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string TagHelperTypeName { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/DeclarePreallocatedTagHelperAttributeIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
 using Microsoft.AspNetCore.Razor.Language.Legacy;
 
@@ -12,8 +11,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
     {
         public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string VariableName { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/DeclarePreallocatedTagHelperHtmlAttributeIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
 using Microsoft.AspNetCore.Razor.Language.Legacy;
 
@@ -12,8 +11,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
     {
         public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string VariableName { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/DeclareTagHelperFieldsIRNode.cs

@@ -12,8 +12,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public ISet<string> UsedTagHelperTypeNames { get; set; } = new HashSet<string>(StringComparer.Ordinal);

src/Microsoft.AspNetCore.Razor.Language/Intermediate/DefaultRazorIRBuilder.cs

@@ -30,8 +30,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
             {
                 throw new ArgumentNullException(nameof(node));
             }
-
+            
-            node.Parent = Current;
             Current.Children.Add(node);
         }
 
@@ -41,8 +40,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
             {
                 throw new ArgumentOutOfRangeException(nameof(index));
             }
-
+            
-            node.Parent = Current;
             if (index == Current.Children.Count)
             {
                 // Allow inserting at 'Children.Count' to be friendlier than List<> typically is.
@@ -95,7 +93,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
             if (_depth > 0)
             {
                 var parent = _stack[_depth - 1];
-                node.Parent = parent;
                 parent.Children.Add(node);
             }
 

src/Microsoft.AspNetCore.Razor.Language/Intermediate/DesignTimeDirectiveIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
@@ -11,8 +10,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
     {
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public override void Accept(RazorIRNodeVisitor visitor)

src/Microsoft.AspNetCore.Razor.Language/Intermediate/DirectiveIRNode.cs

@@ -3,7 +3,6 @@
 
 using System.Collections.Generic;
 using System.Linq;
-using Microsoft.AspNetCore.Razor.Language.Legacy;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
@@ -26,8 +25,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string Name { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/DirectiveTokenIRNode.cs

@@ -1,9 +1,6 @@
 // Copyright(c) .NET Foundation.All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
-using System.Collections.Generic;
-
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public sealed class DirectiveTokenIRNode : RazorIRNode
@@ -12,8 +9,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string Content { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/DocumentIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
@@ -30,8 +29,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public RazorCodeGenerationOptions Options { get; set; }
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public CodeTarget Target { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/FieldDeclarationIRNode.cs

@@ -27,8 +27,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public IList<string> Modifiers { get; set; } = new List<string>();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string AccessModifier { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/HtmlAttributeIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
@@ -12,8 +11,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string Name { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/HtmlAttributeValueIRNode.cs

@@ -12,8 +12,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string Prefix { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/HtmlContentIRNode.cs

@@ -12,8 +12,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public override void Accept(RazorIRNodeVisitor visitor)

src/Microsoft.AspNetCore.Razor.Language/Intermediate/MethodDeclarationIRNode.cs

@@ -25,8 +25,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string AccessModifier { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/NamespaceDeclarationIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
@@ -25,8 +24,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string Content { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/PropertyDeclarationIRNode.cs

@@ -27,8 +27,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public IList<string> Modifiers { get; set; } = new List<string>();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string AccessModifier { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/RazorIRNode.cs

@@ -1,20 +1,14 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System.Collections.Generic;
-
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public abstract class RazorIRNode
     {
-        internal static readonly RazorIRNode[] EmptyArray = new RazorIRNode[0];
-
         public abstract ItemCollection Annotations { get; }
 
         public abstract RazorIRNodeCollection Children { get; }
 
-        public abstract RazorIRNode Parent { get; set; }
-
         public abstract SourceSpan? Source { get; set; }
 
         public abstract void Accept(RazorIRNodeVisitor visitor);

src/Microsoft.AspNetCore.Razor.Language/Intermediate/RazorIRNodeWalker.cs

@@ -1,17 +1,39 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System.Collections.Generic;
+
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public abstract class RazorIRNodeWalker : RazorIRNodeVisitor
     {
+        private readonly Stack<RazorIRNode> _ancestors = new Stack<RazorIRNode>();
+
+        protected IEnumerable<RazorIRNode> Ancestors => _ancestors;
+
+        protected RazorIRNode Parent => _ancestors.Count > 0 ? _ancestors.Peek() : null;
+
         public override void VisitDefault(RazorIRNode node)
         {
             var children = node.Children;
-            for (var i = 0; i < node.Children.Count; i++)
+            if (node.Children.Count == 0)
             {
-                var child = children[i];
+                return;
-                Visit(child);
+            }
+
+            _ancestors.Push(node);
+
+            try
+            {
+                for (var i = 0; i < node.Children.Count; i++)
+                {
+                    var child = children[i];
+                    Visit(child);
+                }
+            }
+            finally
+            {
+                _ancestors.Pop();
             }
         }
     }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/RazorIRToken.cs

@@ -19,8 +19,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public TokenKind Kind { get; set; } = TokenKind.Unknown;
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public override void Accept(RazorIRNodeVisitor visitor)

src/Microsoft.AspNetCore.Razor.Language/Intermediate/SetPreallocatedTagHelperPropertyIRNode.cs

@@ -2,9 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
-using Microsoft.AspNetCore.Razor.Language.Legacy;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
@@ -12,8 +10,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
     {
         public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string VariableName { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/SetTagHelperPropertyIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 using Microsoft.AspNetCore.Razor.Language.Legacy;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
@@ -13,8 +12,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string TagHelperTypeName { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/TagHelperBodyIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
@@ -12,8 +11,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public override void Accept(RazorIRNodeVisitor visitor)

src/Microsoft.AspNetCore.Razor.Language/Intermediate/TagHelperIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
@@ -25,8 +24,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string TagName { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Intermediate/UsingStatementIRNode.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
@@ -12,8 +11,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-        public override RazorIRNode Parent { get; set; }
-
         public override SourceSpan? Source { get; set; }
 
         public string Content { get; set; }

src/Microsoft.AspNetCore.Razor.Language/Microsoft.AspNetCore.Razor.Language.csproj

@@ -11,7 +11,11 @@
   </PropertyGroup>
 
   <ItemGroup>
-     <PackageReference Include="Microsoft.Extensions.HashCodeCombiner.Sources" Version="$(AspNetCoreVersion)" PrivateAssets="All" />
+    <PackageReference Include="Microsoft.Extensions.HashCodeCombiner.Sources" Version="$(AspNetCoreVersion)" PrivateAssets="All" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFrameworkIdentifier)'=='.NETFramework'">
+    <PackageReference Include="System.ValueTuple" Version="$(CoreFxVersion)" />
   </ItemGroup>
 
 </Project>

src/Microsoft.AspNetCore.Razor.Language/RazorPreallocatedTagHelperAttributeOptimizationPass.cs

@@ -72,7 +72,6 @@ namespace Microsoft.AspNetCore.Razor.Language
                         Name = node.Name,
                         Value = plainTextValue,
                         ValueStyle = node.ValueStyle,
-                        Parent = _classDeclaration
                     };
                     _classDeclaration.Children.Insert(_preallocatedDeclarationCount++, declaration);
                 }
@@ -80,11 +79,10 @@ namespace Microsoft.AspNetCore.Razor.Language
                 var addPreAllocatedAttribute = new AddPreallocatedTagHelperHtmlAttributeIRNode
                 {
                     VariableName = declaration.VariableName,
-                    Parent = node.Parent
                 };
 
-                var nodeIndex = node.Parent.Children.IndexOf(node);
+                var nodeIndex = Parent.Children.IndexOf(node);
-                node.Parent.Children[nodeIndex] = addPreAllocatedAttribute;
+                Parent.Children[nodeIndex] = addPreAllocatedAttribute;
             }
 
             public override void VisitSetTagHelperProperty(SetTagHelperPropertyIRNode node)
@@ -127,7 +125,6 @@ namespace Microsoft.AspNetCore.Razor.Language
                         Name = node.AttributeName,
                         Value = plainTextValue,
                         ValueStyle = node.ValueStyle,
-                        Parent = _classDeclaration
                     };
                     _classDeclaration.Children.Insert(_preallocatedDeclarationCount++, declaration);
                 }
@@ -140,12 +137,11 @@ namespace Microsoft.AspNetCore.Razor.Language
                     PropertyName = node.PropertyName,
                     Descriptor = node.Descriptor,
                     Binding = node.Binding,
-                    Parent = node.Parent,
                     IsIndexerNameMatch = node.IsIndexerNameMatch,
                 };
 
-                var nodeIndex = node.Parent.Children.IndexOf(node);
+                var nodeIndex = Parent.Children.IndexOf(node);
-                node.Parent.Children[nodeIndex] = setPreallocatedProperty;
+                Parent.Children[nodeIndex] = setPreallocatedProperty;
             }
 
             private string GetContent(HtmlContentIRNode node)

src/RazorPageGenerator/RemovePragmaChecksumFeature.cs

@@ -13,16 +13,16 @@ namespace RazorPageGenerator
             var walker = new Walker();
             walker.Visit(irDocument);
 
-            walker.ChecksumNode.Parent.Children.Remove(walker.ChecksumNode);
+            walker.Checksum.parent.Children.Remove(walker.Checksum.node);
         }
 
         private class Walker : RazorIRNodeWalker
         {
-            public ChecksumIRNode ChecksumNode { get; private set; }
+            public (ChecksumIRNode node, RazorIRNode parent) Checksum { get; private set; }
 
             public override void VisitChecksum(ChecksumIRNode node)
             {
-                ChecksumNode = node;
+                Checksum = (node, Parent);
             }
         }
     }

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/NamespaceDirectiveTest.cs

@@ -41,7 +41,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
                 Source = new SourceSpan(imports, 0, 0, 0, 0),
             };
             node.Children.Add(new DirectiveTokenIRNode() { Content = string.Empty });
-            node.Children[0].Parent = node;
 
             // Act
             var computed = NamespaceDirective.TryComputeNamespace(source, node, out var @namespace);
@@ -71,7 +70,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             };
 
             node.Children.Add(new DirectiveTokenIRNode() { Content = "Base" });
-            node.Children[0].Parent = node;
 
             // Act
             var computed = NamespaceDirective.TryComputeNamespace(source, node, out var @namespace);
@@ -102,7 +100,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             };
 
             node.Children.Add(new DirectiveTokenIRNode() { Content = "Base" });
-            node.Children[0].Parent = node;
 
             // Act
             var computed = NamespaceDirective.TryComputeNamespace(source, node, out var @namespace);

test/Microsoft.AspNetCore.Razor.Language.Test/CodeGeneration/DesignTimeBasicWriterTest.cs

@@ -551,8 +551,6 @@ Render Node - CSharpExpressionIRNode
         {
             public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-            public override RazorIRNode Parent { get; set; }
-
             public override SourceSpan? Source { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
 
             public override void Accept(RazorIRNodeVisitor visitor)

test/Microsoft.AspNetCore.Razor.Language.Test/CodeGeneration/RuntimeBasicWriterTest.cs

@@ -445,7 +445,6 @@ if (true) { }
             {
                 Content = "SomeContent",
                 Kind = RazorIRToken.TokenKind.Html,
-                Parent = node
             });
 
             // Act
@@ -476,7 +475,6 @@ if (true) { }
             {
                 Content = new string('*', 2000),
                 Kind = RazorIRToken.TokenKind.Html,
-                Parent = node
             });
 
             // Act
@@ -652,7 +650,6 @@ WriteAttributeValue("" "", 27, false, 28, 6, false);
         {
             public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-            public override RazorIRNode Parent { get; set; }
             public override SourceSpan? Source { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
 
             public override void Accept(RazorIRNodeVisitor visitor)

test/Microsoft.AspNetCore.Razor.Language.Test/Intermediate/DefaultRazorIRBuilderTest.cs

@@ -34,11 +34,10 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
             // Assert
             Assert.Same(node, builder.Current);
-            Assert.Null(node.Parent);
         }
 
         [Fact]
-        public void Push_WhenNonEmpty_SetsUpParentAndChild()
+        public void Push_WhenNonEmpty_SetsUpChild()
         {
             // Arrange
             var builder = new DefaultRazorIRBuilder();
@@ -53,7 +52,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
             // Assert
             Assert.Same(node, builder.Current);
-            Assert.Same(parent, node.Parent);
             Assert.Collection(parent.Children, n => Assert.Same(node, n));
         }
 
@@ -122,12 +120,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
             // Assert
             Assert.Same(parent, builder.Current);
-            Assert.Same(parent, node.Parent);
             Assert.Collection(parent.Children, n => Assert.Same(node, n));
         }
 
         [Fact]
-        public void Insert_AddsToChildrenAndSetsParent_EmptyCollection()
+        public void Insert_AddsToChildren_EmptyCollection()
         {
             // Arrange
             var builder = new DefaultRazorIRBuilder();
@@ -142,12 +139,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
             // Assert
             Assert.Same(parent, builder.Current);
-            Assert.Same(parent, node.Parent);
             Assert.Collection(parent.Children, n => Assert.Same(node, n));
         }
 
         [Fact]
-        public void Insert_AddsToChildrenAndSetsParent_NonEmpyCollection()
+        public void Insert_AddsToChildren_NonEmpyCollection()
         {
             // Arrange
             var builder = new DefaultRazorIRBuilder();
@@ -165,12 +161,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
             // Assert
             Assert.Same(parent, builder.Current);
-            Assert.Same(parent, node.Parent);
             Assert.Collection(parent.Children, n => Assert.Same(node, n), n => Assert.Same(child, n));
         }
 
         [Fact]
-        public void Insert_AddsToChildrenAndSetsParent_NonEmpyCollection_AtEnd()
+        public void Insert_AddsToChildren_NonEmpyCollection_AtEnd()
         {
             // Arrange
             var builder = new DefaultRazorIRBuilder();
@@ -188,7 +183,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
             // Assert
             Assert.Same(parent, builder.Current);
-            Assert.Same(parent, node.Parent);
             Assert.Collection(parent.Children, n => Assert.Same(child, n), n => Assert.Same(node, n));
         }
 
@@ -218,8 +212,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
             public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-            public override RazorIRNode Parent { get; set; }
-
             public override SourceSpan? Source { get; set; }
 
             public override void Accept(RazorIRNodeVisitor visitor)

test/Microsoft.AspNetCore.Razor.Language.Test/Intermediate/ExtensionIRNodeTest.cs

@@ -46,7 +46,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
         {
             public override RazorIRNodeCollection Children => ReadOnlyIRNodeCollection.Instance;
 
-            public override RazorIRNode Parent { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
             public override SourceSpan? Source { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
 
             public override void Accept(RazorIRNodeVisitor visitor)

test/Microsoft.AspNetCore.Razor.Language.Test/Intermediate/RazorIRNodeWalkerTest.cs

@@ -74,8 +74,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
             public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
 
-            public override RazorIRNode Parent { get; set; }
-
             public override SourceSpan? Source { get; set; }
 
             public override void Accept(RazorIRNodeVisitor visitor)

test/Microsoft.AspNetCore.Razor.Test.Common/Langauge/IntegrationTests/RazorIRNodeVerifier.cs

@@ -2,7 +2,9 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Text;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
 using Xunit;
@@ -47,7 +49,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 _visitor.Visit(node);
                 var actual = _writer.GetStringBuilder().ToString();
 
-                AssertNodeEquals(node, expected, actual);
+                AssertNodeEquals(node, Ancestors, expected, actual);
 
                 _visitor.Depth++;
                 base.VisitDefault(node);
@@ -60,7 +62,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 Assert.True(_baseline.Length == _index, "Not all lines of the baseline were visited!");
             }
 
-            private void AssertNodeEquals(RazorIRNode node, string expected, string actual)
+            private void AssertNodeEquals(RazorIRNode node, IEnumerable<RazorIRNode> ancestors, string expected, string actual)
             {
                 if (string.Equals(expected, actual))
                 {
@@ -71,21 +73,21 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 if (expected == null)
                 {
                     var message = "The node is missing from baseline.";
-                    throw new IRBaselineException(node, expected, actual, message);
+                    throw new IRBaselineException(node, Ancestors.ToArray(), expected, actual, message);
                 }
 
                 int charsVerified = 0;
-                AssertNestingEqual(node, expected, actual, ref charsVerified);
+                AssertNestingEqual(node, ancestors, expected, actual, ref charsVerified);
-                AssertNameEqual(node, expected, actual, ref charsVerified);
+                AssertNameEqual(node, ancestors, expected, actual, ref charsVerified);
                 AssertDelimiter(node, expected, actual, true, ref charsVerified);
-                AssertLocationEqual(node, expected, actual, ref charsVerified);
+                AssertLocationEqual(node, ancestors, expected, actual, ref charsVerified);
                 AssertDelimiter(node, expected, actual, false, ref charsVerified);
-                AssertContentEqual(node, expected, actual, ref charsVerified);
+                AssertContentEqual(node, ancestors, expected, actual, ref charsVerified);
 
                 throw new InvalidOperationException("We can't figure out HOW these two things are different. This is a bug.");
             }
 
-            private void AssertNestingEqual(RazorIRNode node, string expected, string actual, ref int charsVerified)
+            private void AssertNestingEqual(RazorIRNode node, IEnumerable<RazorIRNode> ancestors, string expected, string actual, ref int charsVerified)
             {
                 var i = 0;
                 for (; i < expected.Length; i++)
@@ -115,13 +117,13 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 if (failed)
                 {
                     var message = "The node is at the wrong level of nesting. This usually means a child is missing.";
-                    throw new IRBaselineException(node, expected, actual, message);
+                    throw new IRBaselineException(node, ancestors.ToArray(), expected, actual, message);
                 }
 
                 charsVerified = j;
             }
 
-            private void AssertNameEqual(RazorIRNode node, string expected, string actual, ref int charsVerified)
+            private void AssertNameEqual(RazorIRNode node, IEnumerable<RazorIRNode> ancestors, string expected, string actual, ref int charsVerified)
             {
                 var expectedName = GetName(expected, charsVerified);
                 var actualName = GetName(actual, charsVerified);
@@ -129,7 +131,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 if (!string.Equals(expectedName, actualName))
                 {
                     var message = $"Node names are not equal.";
-                    throw new IRBaselineException(node, expected, actual, message);
+                    throw new IRBaselineException(node, ancestors.ToArray(), expected, actual, message);
                 }
 
                 charsVerified += expectedName.Length;
@@ -170,7 +172,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 charsVerified += 3;
             }
 
-            private void AssertLocationEqual(RazorIRNode node, string expected, string actual, ref int charsVerified)
+            private void AssertLocationEqual(RazorIRNode node, IEnumerable<RazorIRNode> ancestors, string expected, string actual, ref int charsVerified)
             {
                 var expectedLocation = GetLocation(expected, charsVerified);
                 var actualLocation = GetLocation(actual, charsVerified);
@@ -178,13 +180,13 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 if (!string.Equals(expectedLocation, actualLocation))
                 {
                     var message = $"Locations are not equal.";
-                    throw new IRBaselineException(node, expected, actual, message);
+                    throw new IRBaselineException(node, ancestors.ToArray(), expected, actual, message);
                 }
 
                 charsVerified += expectedLocation.Length;
             }
 
-            private void AssertContentEqual(RazorIRNode node, string expected, string actual, ref int charsVerified)
+            private void AssertContentEqual(RazorIRNode node, IEnumerable<RazorIRNode> ancestors, string expected, string actual, ref int charsVerified)
             {
                 var expectedContent = GetContent(expected, charsVerified);
                 var actualContent = GetContent(actual, charsVerified);
@@ -192,7 +194,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 if (!string.Equals(expectedContent, actualContent))
                 {
                     var message = $"Contents are not equal.";
-                    throw new IRBaselineException(node, expected, actual, message);
+                    throw new IRBaselineException(node, ancestors.ToArray(), expected, actual, message);
                 }
 
                 charsVerified += expectedContent.Length;
@@ -222,8 +224,8 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
 
             private class IRBaselineException : XunitException
             {
-                public IRBaselineException(RazorIRNode node, string expected, string actual, string userMessage)
+                public IRBaselineException(RazorIRNode node, RazorIRNode[] ancestors, string expected, string actual, string userMessage)
-                    : base(Format(node, expected, actual, userMessage))
+                    : base(Format(node, ancestors, expected, actual, userMessage))
                 {
                     Node = node;
                     Expected = expected;
@@ -236,7 +238,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
 
                 public string Expected { get; }
 
-                private static string Format(RazorIRNode node, string expected, string actual, string userMessage)
+                private static string Format(RazorIRNode node, RazorIRNode[] ancestors, string expected, string actual, string userMessage)
                 {
                     var builder = new StringBuilder();
                     builder.AppendLine(userMessage);
@@ -254,15 +256,16 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                         builder.AppendLine(actual);
                     }
 
-                    builder.AppendLine();
+                    if (ancestors != null)
-                    builder.AppendLine("Path:");
-
-                    var current = node;
-                    do
                     {
-                        builder.AppendLine(current.ToString());
+                        builder.AppendLine();
+                        builder.AppendLine("Path:");
+
+                        foreach (var ancestor in ancestors)
+                        {
+                            builder.AppendLine(ancestor.ToString());
+                        }
                     }
-                    while ((current = current.Parent) != null);
 
                     return builder.ToString();
                 }

test/Microsoft.AspNetCore.Razor.Test.Common/Langauge/Intermediate/RazorIRAssert.cs

@@ -431,13 +431,13 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
         private class IRAssertException : XunitException
         {
             public IRAssertException(RazorIRNode node, string userMessage)
-                : base(Format(node, null, userMessage))
+                : base(Format(node, null, null, userMessage))
             {
                 Node = node;
             }
 
             public IRAssertException(RazorIRNode node, IEnumerable<RazorIRNode> nodes, string userMessage)
-                : base(Format(node, nodes, userMessage))
+                : base(Format(node, null, nodes, userMessage))
             {
                 Node = node;
                 Nodes = nodes;
@@ -448,7 +448,17 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
                 IEnumerable<RazorIRNode> nodes,
                 string userMessage,
                 Exception innerException)
-                : base(Format(node, nodes, userMessage), innerException)
+                : base(Format(node, null, nodes, userMessage), innerException)
+            {
+            }
+
+            public IRAssertException(
+                RazorIRNode node,
+                RazorIRNode[] ancestors,
+                IEnumerable<RazorIRNode> nodes,
+                string userMessage,
+                Exception innerException)
+                : base(Format(node, ancestors, nodes, userMessage), innerException)
             {
             }
 
@@ -456,7 +466,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
             public IEnumerable<RazorIRNode> Nodes { get; }
 
-            private static string Format(RazorIRNode node, IEnumerable<RazorIRNode> nodes, string userMessage)
+            private static string Format(RazorIRNode node, RazorIRNode[] ancestors, IEnumerable<RazorIRNode> nodes, string userMessage)
             {
                 var builder = new StringBuilder();
                 builder.AppendLine(userMessage);
@@ -477,12 +487,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
                 builder.AppendLine("Path:");
 
-                var current = node;
+                if (ancestors != null)
-                do
                 {
-                    builder.AppendLine(current.ToString());
+                    builder.AppendLine();
+                    builder.AppendLine("Path:");
+
+                    foreach (var ancestor in ancestors)
+                    {
+                        builder.AppendLine(ancestor.ToString());
+                    }
                 }
-                while ((current = current.Parent) != null);
 
                 return builder.ToString();
             }