Add annotations

Fixes #990. This should make a lot of IR manipulations very simple.

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

@@ -48,24 +48,14 @@ namespace Microsoft.AspNetCore.Razor.Language
             var children = new List<RazorIRNode>(irDocument.Children);
             irDocument.Children.Clear();
 
-            var @namespace = new NamespaceDeclarationIRNode()
-            {
-                //Content = "GeneratedNamespace",
-            };
+            var @namespace = new NamespaceDeclarationIRNode();
+            @namespace.Annotations[CommonAnnotations.PrimaryNamespace] = CommonAnnotations.PrimaryNamespace;
 
-            var @class = new ClassDeclarationIRNode()
-            {
-                //AccessModifier = "public",
-                //Name = "GeneratedClass",
-            };
+            var @class = new ClassDeclarationIRNode();
+            @class.Annotations[CommonAnnotations.PrimaryClass] = CommonAnnotations.PrimaryClass;
 
-            var method = new RazorMethodDeclarationIRNode()
-            {
-                //AccessModifier = "public",
-                // Modifiers = new List<string>() { "async" },
-                //Name = "Execute",
-                //ReturnType = "Task",
-            };
+            var method = new RazorMethodDeclarationIRNode();
+            method.Annotations[CommonAnnotations.PrimaryMethod] = CommonAnnotations.PrimaryMethod;
 
             var documentBuilder = RazorIRBuilder.Create(irDocument);
 

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

@@ -9,6 +9,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class AddTagHelperHtmlAttributeIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -8,6 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class CSharpAttributeValueIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -8,6 +8,21 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class CSharpExpressionIRNode : RazorIRNode
     {
+        private ItemCollection _annotations;
+
+        public override ItemCollection Annotations
+        {
+            get
+            {
+                if (_annotations == null)
+                {
+                    _annotations = new DefaultItemCollection();
+                }
+
+                return _annotations;
+            }
+        }
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -8,6 +8,21 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class CSharpStatementIRNode : RazorIRNode
     {
+        private ItemCollection _annotations;
+
+        public override ItemCollection Annotations
+        {
+            get
+            {
+                if (_annotations == null)
+                {
+                    _annotations = new DefaultItemCollection();
+                }
+
+                return _annotations;
+            }
+        }
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -9,6 +9,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class ChecksumIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children => EmptyArray;
 
         public override RazorIRNode Parent { get; set; }

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

@@ -8,6 +8,20 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class ClassDeclarationIRNode : RazorIRNode
     {
+        private ItemCollection _annotations;
+
+        public override ItemCollection Annotations
+        {
+            get
+            {
+                if (_annotations == null)
+                {
+                    _annotations = new DefaultItemCollection();
+                }
+
+                return _annotations;
+            }
+        }
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -0,0 +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.
+
+namespace Microsoft.AspNetCore.Razor.Language.Intermediate
+{
+    internal static class CommonAnnotations
+    {
+        public static readonly object PrimaryClass = "PrimaryClass";
+
+        public static readonly object PrimaryMethod = "PrimaryMethod";
+
+        public static readonly object PrimaryNamespace = "PrimaryNamespace";
+    }
+}

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

@@ -8,6 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class CreateTagHelperIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children { get; } = EmptyArray;
 
         public override RazorIRNode Parent { get; set; }

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

@@ -8,6 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class DeclareTagHelperFieldsIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children { get; } = EmptyArray;
 
         public override RazorIRNode Parent { get; set; }

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

@@ -9,6 +9,21 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class DirectiveIRNode : RazorIRNode
     {
+        private ItemCollection _annotations;
+
+        public override ItemCollection Annotations
+        {
+            get
+            {
+                if (_annotations == null)
+                {
+                    _annotations = new DefaultItemCollection();
+                }
+
+                return _annotations;
+            }
+        }
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -8,6 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class DirectiveTokenIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children { get; } = EmptyArray;
 
         public override RazorIRNode Parent { get; set; }

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

@@ -9,6 +9,21 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public sealed class DocumentIRNode : RazorIRNode
     {
+        private ItemCollection _annotations;
+
+        public override ItemCollection Annotations
+        {
+            get
+            {
+                if (_annotations == null)
+                {
+                    _annotations = new DefaultItemCollection();
+                }
+
+                return _annotations;
+            }
+        }
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public string DocumentKind { get; set; }

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

@@ -0,0 +1,59 @@
+// 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;
+
+namespace Microsoft.AspNetCore.Razor.Language.Intermediate
+{
+    public static class DocumentIRNodeExtensions
+    {
+        public static ClassDeclarationIRNode FindPrimaryClass(this DocumentIRNode node)
+        {
+            if (node == null)
+            {
+                throw new ArgumentNullException(nameof(node));
+            }
+
+            return FindWithAnnotation<ClassDeclarationIRNode>(node, CommonAnnotations.PrimaryClass);
+        }
+
+        public static RazorMethodDeclarationIRNode FindPrimaryMethod(this DocumentIRNode node)
+        {
+            if (node == null)
+            {
+                throw new ArgumentNullException(nameof(node));
+            }
+
+            return FindWithAnnotation<RazorMethodDeclarationIRNode>(node, CommonAnnotations.PrimaryMethod);
+        }
+
+        public static NamespaceDeclarationIRNode FindPrimaryNamespace(this DocumentIRNode node)
+        {
+            if (node == null)
+            {
+                throw new ArgumentNullException(nameof(node));
+            }
+
+            return FindWithAnnotation<NamespaceDeclarationIRNode>(node, CommonAnnotations.PrimaryNamespace);
+        }
+
+        private static T FindWithAnnotation<T>(RazorIRNode node, object annotation) where T : RazorIRNode
+        {
+            if (node is T target && object.ReferenceEquals(target.Annotations[annotation], annotation))
+            {
+                return target;
+            }
+
+            for (var i = 0; i < node.Children.Count; i++)
+            {
+                var result = FindWithAnnotation<T>(node.Children[i], annotation);
+                if (result != null)
+                {
+                    return result;
+                }
+            }
+
+            return null;
+        }
+    }
+}

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

@@ -8,6 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class ExecuteTagHelpersIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -7,6 +7,21 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public abstract class ExtensionIRNode : RazorIRNode
     {
+        private ItemCollection _annotations;
+
+        public override ItemCollection Annotations
+        {
+            get
+            {
+                if (_annotations == null)
+                {
+                    _annotations = new DefaultItemCollection();
+                }
+
+                return _annotations;
+            }
+        }
+
         public abstract void WriteNode(RuntimeTarget target, CSharpRenderingContext context);
 
         protected static void AcceptExtensionNode<TNode>(TNode node, RazorIRNodeVisitor visitor) 

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

@@ -8,6 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class HtmlAttributeIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -8,6 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class HtmlAttributeValueIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children { get; } = EmptyArray;
 
         public override RazorIRNode Parent { get; set; }

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

@@ -8,6 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public sealed class HtmlContentIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -3,12 +3,13 @@
 
 using System;
 using System.Collections.Generic;
-using Microsoft.AspNetCore.Razor.Language.Legacy;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
-    public class InitializeTagHelperStructureIRNode : RazorIRNode
+    public sealed class InitializeTagHelperStructureIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -8,6 +8,21 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class NamespaceDeclarationIRNode : RazorIRNode
     {
+        private ItemCollection _annotations;
+
+        public override ItemCollection Annotations
+        {
+            get
+            {
+                if (_annotations == null)
+                {
+                    _annotations = new DefaultItemCollection();
+                }
+
+                return _annotations;
+            }
+        }
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -9,6 +9,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
     {
         internal static readonly RazorIRNode[] EmptyArray = new RazorIRNode[0];
 
+        public abstract ItemCollection Annotations { get; }
+
         public abstract IList<RazorIRNode> Children { get; }
 
         public abstract RazorIRNode Parent { get; set; }

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

@@ -8,6 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public sealed class RazorIRToken : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children => RazorIRNode.EmptyArray;
 
         public string Content { get; set; }

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

@@ -8,6 +8,21 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class RazorMethodDeclarationIRNode : RazorIRNode
     {
+        private ItemCollection _annotations;
+
+        public override ItemCollection Annotations
+        {
+            get
+            {
+                if (_annotations == null)
+                {
+                    _annotations = new DefaultItemCollection();
+                }
+
+                return _annotations;
+            }
+        }
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -9,6 +9,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class SetTagHelperPropertyIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -8,6 +8,21 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class TagHelperIRNode : RazorIRNode
     {
+        private ItemCollection _annotations;
+
+        public override ItemCollection Annotations
+        {
+            get
+            {
+                if (_annotations == null)
+                {
+                    _annotations = new DefaultItemCollection();
+                }
+
+                return _annotations;
+            }
+        }
+
         public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
         public override RazorIRNode Parent { get; set; }

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

@@ -8,6 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 {
     public class UsingStatementIRNode : RazorIRNode
     {
+        public override ItemCollection Annotations => ReadonlyItemCollection.Empty;
+
         public override IList<RazorIRNode> Children { get; } = EmptyArray;
 
         public override RazorIRNode Parent { get; set; }

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

@@ -0,0 +1,18 @@
+// 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;
+
+namespace Microsoft.AspNetCore.Razor.Language
+{
+    internal class ReadonlyItemCollection : ItemCollection
+    {
+        public static readonly ItemCollection Empty = new ReadonlyItemCollection();
+
+        public override object this[object key]
+        {
+            get => null;
+            set => throw new NotSupportedException();
+        }
+    }
+}

test/Microsoft.AspNetCore.Razor.Language.Test/DocumentClassifierPassBaseTest.cs

@@ -259,6 +259,41 @@ namespace Microsoft.AspNetCore.Razor.Language
             Assert.Equal("TestMethod", method.Name);
         }
 
+        [Fact]
+        public void Execute_AddsPrimaryAnnotations()
+        {
+            // Arrange
+            var irDocument = new DocumentIRNode()
+            {
+                Options = RazorParserOptions.CreateDefaultOptions(),
+            };
+
+            var builder = RazorIRBuilder.Create(irDocument);
+            builder.Add(new HtmlContentIRNode());
+            builder.Add(new CSharpStatementIRNode());
+
+            var pass = new TestDocumentClassifierPass()
+            {
+                Engine = RazorEngine.CreateEmpty(b => { }),
+                Namespace = "TestNamespace",
+                Class = "TestClass",
+                Method = "TestMethod",
+            };
+
+            // Act
+            pass.Execute(TestRazorCodeDocument.CreateEmpty(), irDocument);
+
+            // Assert
+            var @namespace = SingleChild<NamespaceDeclarationIRNode>(irDocument);
+            AnnotationEquals(@namespace, CommonAnnotations.PrimaryNamespace);
+
+            var @class = SingleChild<ClassDeclarationIRNode>(@namespace);
+            AnnotationEquals(@class, CommonAnnotations.PrimaryClass);
+
+            var method = SingleChild<RazorMethodDeclarationIRNode>(@class);
+            AnnotationEquals(method, CommonAnnotations.PrimaryMethod);
+        }
+
         private class TestDocumentClassifierPass : DocumentClassifierPassBase
         {
             public override int Order => RazorIRPass.DefaultFeatureOrder;

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

@@ -214,6 +214,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         private class BasicIRNode : RazorIRNode
         {
+            public override ItemCollection Annotations { get; } = new DefaultItemCollection();
+
             public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
             public override RazorIRNode Parent { get; set; }

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

@@ -0,0 +1,64 @@
+// 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 Xunit;
+
+namespace Microsoft.AspNetCore.Razor.Language.Intermediate
+{
+    public class DocumentIRNodeExtensionsTest
+    {
+        [Fact]
+        public void FindPrimaryClass_FindsClassWithAnnotation()
+        {
+            // Arrange
+            var document = new DocumentIRNode();
+            var @class = new ClassDeclarationIRNode();
+            @class.Annotations[CommonAnnotations.PrimaryClass] = CommonAnnotations.PrimaryClass;
+
+            var builder = RazorIRBuilder.Create(document);
+            builder.Add(@class);
+
+            // Act
+            var result = document.FindPrimaryClass();
+
+            // Assert
+            Assert.Same(@class, result);
+        }
+
+        [Fact]
+        public void FindPrimaryMethod_FindsMethodWithAnnotation()
+        {
+            // Arrange
+            var document = new DocumentIRNode();
+            var method = new RazorMethodDeclarationIRNode();
+            method.Annotations[CommonAnnotations.PrimaryMethod] = CommonAnnotations.PrimaryMethod;
+
+            var builder = RazorIRBuilder.Create(document);
+            builder.Add(method);
+
+            // Act
+            var result = document.FindPrimaryMethod();
+
+            // Assert
+            Assert.Same(method, result);
+        }
+
+        [Fact]
+        public void FindPrimaryNamespace_FindsNamespaceWithAnnotation()
+        {
+            // Arrange
+            var document = new DocumentIRNode();
+            var @namespace = new NamespaceDeclarationIRNode();
+            @namespace.Annotations[CommonAnnotations.PrimaryNamespace] = CommonAnnotations.PrimaryNamespace;
+
+            var builder = RazorIRBuilder.Create(document);
+            builder.Add(@namespace);
+
+            // Act
+            var result = document.FindPrimaryNamespace();
+
+            // Assert
+            Assert.Same(@namespace, result);
+        }
+    }
+}

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

@@ -61,6 +61,37 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
             }
         }
 
+        public static void AnnotationEquals(RazorIRNode node, object value)
+        {
+            AnnotationEquals(node, value, value);
+        }
+
+        public static void AnnotationEquals(RazorIRNode node, object key, object value)
+        {
+            try
+            {
+                Assert.NotNull(node);
+                Assert.Equal(value, node.Annotations[key]);
+            }
+            catch (XunitException e)
+            {
+                throw new IRAssertException(node, node.Children, e.Message, e);
+            }
+        }
+
+        public static void HasAnnotation(RazorIRNode node, object key)
+        {
+            try
+            {
+                Assert.NotNull(node);
+                Assert.NotNull(node.Annotations[key]);
+            }
+            catch (XunitException e)
+            {
+                throw new IRAssertException(node, node.Children, e.Message, e);
+            }
+        }
+
         public static void Html(string expected, RazorIRNode node)
         {
             try

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

@@ -74,6 +74,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         private class BasicIRNode : RazorIRNode
         {
+            public override ItemCollection Annotations { get; } = new DefaultItemCollection();
+
             public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
             public override RazorIRNode Parent { get; set; }
@@ -88,6 +90,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         private class BasicIRNode2 : RazorIRNode
         {
+            public override ItemCollection Annotations { get; } = new DefaultItemCollection();
+
             public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
             public override RazorIRNode Parent { get; set; }
@@ -102,6 +106,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
         private class BasicIRNode3 : RazorIRNode
         {
+            public override ItemCollection Annotations { get; } = new DefaultItemCollection();
+
             public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
             public override RazorIRNode Parent { get; set; }

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

@@ -70,6 +70,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Intermediate
 
             public string Name { get; }
 
+            public override ItemCollection Annotations { get; } = new DefaultItemCollection();
+
             public override IList<RazorIRNode> Children { get; } = new List<RazorIRNode>();
 
             public override RazorIRNode Parent { get; set; }