Moved CreateTagHelperIRNode from renderer to writer

src/Microsoft.AspNetCore.Razor.Evolution/CodeGeneration/DefaultDocumentWriter.cs

@@ -206,6 +206,11 @@ namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
                 Context.TagHelperWriter.WriteInitializeTagHelperStructure(Context, node);
             }
 
+            public override void VisitCreateTagHelper(CreateTagHelperIRNode node)
+            {
+                Context.TagHelperWriter.WriteCreateTagHelper(Context, node);
+            }
+
             public override void VisitDefault(RazorIRNode node)
             {
                 // This is a temporary bridge to the renderer, which allows us to move functionality piecemeal

src/Microsoft.AspNetCore.Razor.Evolution/CodeGeneration/DesignTimeCSharpRenderer.cs

@@ -204,18 +204,6 @@ namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
             Context.Writer.WriteLine("))();");
         }
 
-        public override void VisitCreateTagHelper(CreateTagHelperIRNode node)
-        {
-            var tagHelperVariableName = GetTagHelperVariableName(node.TagHelperTypeName);
-
-            Context.Writer
-                .WriteStartAssignment(tagHelperVariableName)
-                .WriteStartMethodInvocation(
-                    "CreateTagHelper" /* ORIGINAL: CreateTagHelperMethodName */,
-                    "global::" + node.TagHelperTypeName)
-                .WriteEndMethodInvocation();
-        }
-
         public override void VisitSetTagHelperProperty(SetTagHelperPropertyIRNode node)
         {
             var tagHelperVariableName = GetTagHelperVariableName(node.TagHelperTypeName);

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

@@ -8,6 +8,8 @@ namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
 {
     public class DesignTimeTagHelperWriter : TagHelperWriter
     {
+        public string CreateTagHelperMethodName { get; set; } = "CreateTagHelper";
+
         public override void WriteDeclareTagHelperFields(CSharpRenderingContext context, DeclareTagHelperFieldsIRNode node)
         {
             foreach (var tagHelperTypeName in node.UsedTagHelperTypeNames)
@@ -29,7 +31,14 @@ namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
 
         public override void WriteCreateTagHelper(CSharpRenderingContext context, CreateTagHelperIRNode node)
         {
-            throw new NotImplementedException();
+            var tagHelperVariableName = GetTagHelperVariableName(node.TagHelperTypeName);
+
+            context.Writer
+                .WriteStartAssignment(tagHelperVariableName)
+                .WriteStartMethodInvocation(
+                    CreateTagHelperMethodName,
+                    "global::" + node.TagHelperTypeName)
+                .WriteEndMethodInvocation();
         }
 
         public override void WriteExecuteTagHelpers(CSharpRenderingContext context, ExecuteTagHelpersIRNode node)

src/Microsoft.AspNetCore.Razor.Evolution/CodeGeneration/RuntimeCSharpRenderer.cs

@@ -255,23 +255,6 @@ namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
             linePragmaScope?.Dispose();
         }
 
-        public override void VisitCreateTagHelper(CreateTagHelperIRNode node)
-        {
-            var tagHelperVariableName = GetTagHelperVariableName(node.TagHelperTypeName);
-
-            Context.Writer
-                .WriteStartAssignment(tagHelperVariableName)
-                .WriteStartMethodInvocation(
-                    "CreateTagHelper" /* ORIGINAL: CreateTagHelperMethodName */,
-                    "global::" + node.TagHelperTypeName)
-                .WriteEndMethodInvocation();
-
-            Context.Writer.WriteInstanceMethodInvocation(
-                "__tagHelperExecutionContext" /* ORIGINAL: ExecutionContextVariableName */,
-                "Add" /* ORIGINAL: ExecutionContextAddMethodName */,
-                tagHelperVariableName);
-        }
-
         public override void VisitAddPreallocatedTagHelperHtmlAttribute(AddPreallocatedTagHelperHtmlAttributeIRNode node)
         {
             Context.Writer

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

@@ -14,6 +14,8 @@ namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
 
         public string ExecutionContextVariableName { get; set; } = "__tagHelperExecutionContext";
 
+        public string ExecutionContextAddMethodName { get; set; } = "Add";
+
         public string RunnerTypeName { get; set; } = "global::Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperRunner";
 
         public string RunnerVariableName { get; set; } = "__tagHelperRunner";
@@ -30,6 +32,8 @@ namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
 
         public string TagModeTypeName { get; set; } = "global::Microsoft.AspNetCore.Razor.TagHelpers.TagMode";
 
+        public string CreateTagHelperMethodName { get; set; } = "CreateTagHelper";
+
         public override void WriteDeclareTagHelperFields(CSharpRenderingContext context, DeclareTagHelperFieldsIRNode node)
         {
             context.Writer.WriteLineHiddenDirective();
@@ -116,7 +120,19 @@ namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
 
         public override void WriteCreateTagHelper(CSharpRenderingContext context, CreateTagHelperIRNode node)
         {
-            throw new NotImplementedException();
+            var tagHelperVariableName = GetTagHelperVariableName(node.TagHelperTypeName);
+
+            context.Writer
+                .WriteStartAssignment(tagHelperVariableName)
+                .WriteStartMethodInvocation(
+                     CreateTagHelperMethodName,
+                    "global::" + node.TagHelperTypeName)
+                .WriteEndMethodInvocation();
+
+            context.Writer.WriteInstanceMethodInvocation(
+                ExecutionContextVariableName,
+                ExecutionContextAddMethodName,
+                tagHelperVariableName);
         }
 
         public override void WriteExecuteTagHelpers(CSharpRenderingContext context, ExecuteTagHelpersIRNode node)

test/Microsoft.AspNetCore.Razor.Evolution.Test/CodeGeneration/DesignTimeTagHelperWriterTest.cs

@@ -29,6 +29,32 @@ namespace Microsoft.AspNetCore.Razor.Evolution.CodeGeneration
             Assert.Equal(
 @"private global::PTagHelper __PTagHelper = null;
 private global::MyTagHelper __MyTagHelper = null;
+",
+                csharp,
+                ignoreLineEndingDifferences: true);
+        }
+
+        [Fact]
+        public void WriteCreateTagHelper_RendersCorrectly_UsesSpecifiedTagHelperType()
+        {
+            // Arrange
+            var writer = new DesignTimeTagHelperWriter();
+            var context = new CSharpRenderingContext()
+            {
+                Writer = new Legacy.CSharpCodeWriter(),
+            };
+            var node = new CreateTagHelperIRNode()
+            {
+                TagHelperTypeName = "TestNamespace.MyTagHelper"
+            };
+
+            // Act
+            writer.WriteCreateTagHelper(context, node);
+
+            // Assert
+            var csharp = context.Writer.Builder.ToString();
+            Assert.Equal(
+@"__TestNamespace_MyTagHelper = CreateTagHelper<global::TestNamespace.MyTagHelper>();
 ",
                 csharp,
                 ignoreLineEndingDifferences: true);

test/Microsoft.AspNetCore.Razor.Evolution.Test/CodeGeneration/RuntimeTagHelperWriterTest.cs

@@ -119,6 +119,33 @@ private global::MyTagHelper __MyTagHelper = null;
 @"__tagHelperExecutionContext = __tagHelperScopeManager.Begin(""p"", global::Microsoft.AspNetCore.Razor.TagHelpers.TagMode.SelfClosing, ""test"", async() => {
 }
 );
+",
+                csharp,
+                ignoreLineEndingDifferences: true);
+        }
+
+        [Fact]
+        public void WriteCreateTagHelper_RendersCorrectly_UsesSpecifiedTagHelperType()
+        {
+            // Arrange
+            var writer = new RuntimeTagHelperWriter();
+            var context = new CSharpRenderingContext()
+            {
+                Writer = new Legacy.CSharpCodeWriter(),
+            };
+            var node = new CreateTagHelperIRNode()
+            {
+                TagHelperTypeName = "TestNamespace.MyTagHelper"
+            };
+
+            // Act
+            writer.WriteCreateTagHelper(context, node);
+
+            // Assert
+            var csharp = context.Writer.Builder.ToString();
+            Assert.Equal(
+@"__TestNamespace_MyTagHelper = CreateTagHelper<global::TestNamespace.MyTagHelper>();
+__tagHelperExecutionContext.Add(__TestNamespace_MyTagHelper);
 ",
                 csharp,
                 ignoreLineEndingDifferences: true);