Make section an extension node

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

@@ -5,7 +5,7 @@ using Microsoft.AspNetCore.Razor.Language.Intermediate;
 
 namespace Microsoft.AspNetCore.Razor.Language.Extensions
 {
-    public class FunctionsDirectivePass : RazorIRPassBase, IRazorDirectiveClassifierPass
+    public sealed class FunctionsDirectivePass : RazorIRPassBase, IRazorDirectiveClassifierPass
     {
         protected override void ExecuteCore(RazorCodeDocument codeDocument, DocumentIRNode irDocument)
         {

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

@@ -0,0 +1,12 @@
+// 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 Microsoft.AspNetCore.Razor.Language.CodeGeneration;
+
+namespace Microsoft.AspNetCore.Razor.Language.Extensions
+{
+    public interface ISectionTargetExtension : ICodeTargetExtension
+    {
+        void WriteSection(CSharpRenderingContext context, SectionIRNode node);
+    }
+}

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

@@ -7,7 +7,7 @@ using Microsoft.AspNetCore.Razor.Language.Intermediate;
 
 namespace Microsoft.AspNetCore.Razor.Language.Extensions
 {
-    public class InheritsDirectivePass : RazorIRPassBase, IRazorDirectiveClassifierPass
+    public sealed class InheritsDirectivePass : RazorIRPassBase, IRazorDirectiveClassifierPass
     {
         protected override void ExecuteCore(RazorCodeDocument codeDocument, DocumentIRNode irDocument)
         {

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

@@ -16,6 +16,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
         {
             builder.AddDirective(Directive);
             builder.Features.Add(new SectionDirectivePass());
+            builder.AddTargetExtension(new SectionTargetExtension());
         }
     }
 }

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

@@ -7,7 +7,7 @@ using Microsoft.AspNetCore.Razor.Language.Intermediate;
 
 namespace Microsoft.AspNetCore.Razor.Language.Extensions
 {
-    public class SectionDirectivePass : RazorIRPassBase, IRazorDirectiveClassifierPass
+    public sealed class SectionDirectivePass : RazorIRPassBase, IRazorDirectiveClassifierPass
     {
         protected override void ExecuteCore(RazorCodeDocument codeDocument, DocumentIRNode irDocument)
         {
@@ -17,30 +17,30 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
                 return;
             }
 
-            foreach (var section in irDocument.FindDirectiveReferences(SectionDirective.Directive))
+            foreach (var directive in irDocument.FindDirectiveReferences(SectionDirective.Directive))
             {
-                var lambdaContent = irDocument.Options.DesignTime ? "__razor_section_writer" : string.Empty;
+                var sectionName = ((DirectiveIRNode)directive.Node).Tokens.FirstOrDefault()?.Content;
-                var sectionName = ((DirectiveIRNode)section.Node).Tokens.FirstOrDefault()?.Content;
 
-                var builder = RazorIRBuilder.Create(new CSharpCodeIRNode());
+                var section = new SectionIRNode()
-                builder.Add(new RazorIRToken()
                 {
-                    Kind = RazorIRToken.TokenKind.CSharp,
+                    Name = sectionName,
-                    Content = $"DefineSection(\"{sectionName}\", async ({lambdaContent}) => {{"
+                };
-                });
-                section.InsertBefore(builder.Build());
 
-                section.InsertBefore(section.Node.Children.Except(((DirectiveIRNode)section.Node).Tokens));
+                var i = 0;
-
+                for (; i < directive.Node.Children.Count; i++)
-                builder = RazorIRBuilder.Create(new CSharpCodeIRNode());
-                builder.Add(new RazorIRToken()
                 {
-                    Kind = RazorIRToken.TokenKind.CSharp,
+                    if (!(directive.Node.Children[i] is DirectiveTokenIRNode))
-                    Content = "});"
+                    {
-                });
+                        break;
-                section.InsertAfter(builder.Build());
+                    }
+                }
 
-                section.Remove();
+                for (; i < directive.Node.Children.Count; i++)
+                {
+                    section.Children.Add(directive.Node.Children[i]);
+                }
+
+                directive.Replace(section);
             }
         }
     }

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

@@ -0,0 +1,50 @@
+// 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 Microsoft.AspNetCore.Razor.Language.CodeGeneration;
+using Microsoft.AspNetCore.Razor.Language.Intermediate;
+
+namespace Microsoft.AspNetCore.Razor.Language.Extensions
+{
+    public sealed class SectionIRNode : ExtensionIRNode
+    {
+        public override RazorIRNodeCollection Children { get; } = new DefaultIRNodeCollection();
+
+        public string Name { get; set; }
+
+        public override SourceSpan? Source { get; set; }
+
+        public override void Accept(RazorIRNodeVisitor visitor)
+        {
+            if (visitor == null)
+            {
+                throw new ArgumentNullException(nameof(visitor));
+            }
+
+            AcceptExtensionNode<SectionIRNode>(this, visitor);
+        }
+
+        public override void WriteNode(CodeTarget target, CSharpRenderingContext context)
+        {
+            if (target == null)
+            {
+                throw new ArgumentNullException(nameof(target));
+            }
+
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            var extension = target.GetExtension<ISectionTargetExtension>();
+            if (extension == null)
+            {
+                context.ReportMissingExtension<ISectionTargetExtension>();
+                return;
+            }
+
+            extension.WriteSection(context, this);
+        }
+    }
+}

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

@@ -0,0 +1,43 @@
+// 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 Microsoft.AspNetCore.Razor.Language.CodeGeneration;
+
+namespace Microsoft.AspNetCore.Razor.Language.Extensions
+{
+    public sealed class SectionTargetExtension : ISectionTargetExtension
+    {
+        private static readonly string DefaultWriterName = "__razor_section_writer";
+
+        public static readonly string DefaultSectionMethodName = "DefineSection";
+
+        public string SectionMethodName { get; set; } = DefaultSectionMethodName;
+
+        public void WriteSection(CSharpRenderingContext context, SectionIRNode node)
+        {
+            // Quirk Alert!
+            //
+            // In 1.0.0 Razor/MVC the define section method took a parameter for a TextWriter
+            // that would be used for all of the output in the section. We simplified this API for
+            // 2.0.0 of MVC, but our design time codegen still needs to target 1.0.0.
+            //
+            // So the workaround is MVC 2.0.0 will define these methods with the TextWriter, but
+            // that method is never called. We still generate the call *with* the TextWriter for 
+            // design time, at least until we have multi-targeting.
+            var writerName = context.Options.DesignTime ? DefaultWriterName : string.Empty;
+
+            context.Writer
+                .WriteStartMethodInvocation(SectionMethodName)
+                .Write("\"")
+                .Write(node.Name)
+                .Write("\", ");
+
+            using (context.Writer.BuildAsyncLambda(endLine: false, parameterNames: writerName))
+            {
+                context.RenderChildren(node);
+            }
+
+            context.Writer.WriteEndMethodInvocation(endLine: true);
+        }
+    }
+}

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

@@ -5,7 +5,7 @@ using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
 
 namespace Microsoft.AspNetCore.Razor.Language.Extensions
 {
-    public class TemplateTargetExtension : ITemplateTargetExtension
+    public sealed class TemplateTargetExtension : ITemplateTargetExtension
     {
         public static readonly string DefaultTemplateTypeName = "Template";
 

test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/SectionDirectivePassTest.cs

@@ -35,7 +35,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
         }
 
         [Fact]
-        public void Execute_WrapsStatementInDefineSection()
+        public void Execute_WrapsStatementInSectionNode()
         {
             // Arrange
             var engine = CreateEngine();
@@ -65,49 +65,10 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
 
             var @class = @namespace.Children[0];
             var method = SingleChild<MethodDeclarationIRNode>(@class);
-            Children(
-                method,
-                node => CSharpCode("DefineSection(\"Header\", async () => {", node),
-                node => Html(" <p>Hello World</p> ", node),
-                node => CSharpCode("});", node));
-        }
 
-        [Fact]
+            var section = SingleChild<SectionIRNode>(method);
-        public void Execute_DesignTime_WrapsStatementInBackwardsCompatibleDefineSection()
+            Assert.Equal("Header", section.Name);
-        {
+            Children(section, c => Html(" <p>Hello World</p> ", c));
-            // Arrange
-            var engine = CreateDesignTimeEngine();
-            var pass = new SectionDirectivePass()
-            {
-                Engine = engine,
-            };
-
-            var content = "@section Header { <p>Hello World</p> }";
-            var sourceDocument = TestRazorSourceDocument.Create(content);
-            var codeDocument = RazorCodeDocument.Create(sourceDocument);
-
-            var irDocument = Lower(codeDocument, engine);
-
-            // Act
-            pass.Execute(codeDocument, irDocument);
-
-            // Assert
-            Children(
-                irDocument,
-                node => Assert.IsType<NamespaceDeclarationIRNode>(node));
-
-            var @namespace = irDocument.Children[0];
-            Children(
-                @namespace,
-                node => Assert.IsType<ClassDeclarationIRNode>(node));
-
-            var @class = @namespace.Children[0];
-            var method = SingleChild<MethodDeclarationIRNode>(@class);
-            Children(
-                method,
-                node => CSharpCode("DefineSection(\"Header\", async (__razor_section_writer) => {", node),
-                node => Html(" <p>Hello World</p> ", node),
-                node => CSharpCode("});", node));
         }
 
         private static RazorEngine CreateEngine()
@@ -118,14 +79,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
             });
         }
 
-        private static RazorEngine CreateDesignTimeEngine()
-        {
-            return RazorEngine.CreateDesignTime(b =>
-            {
-                SectionDirective.Register(b);
-            });
-        }
-
         private static DocumentIRNode Lower(RazorCodeDocument codeDocument, RazorEngine engine)
         {
             for (var i = 0; i < engine.Phases.Count; i++)

test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/SectionTargetExtensionTest.cs

@@ -0,0 +1,97 @@
+// 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 Microsoft.AspNetCore.Razor.Language.CodeGeneration;
+using Microsoft.AspNetCore.Razor.Language.Legacy;
+using Xunit;
+using static Microsoft.AspNetCore.Razor.Language.Intermediate.RazorIRAssert;
+
+namespace Microsoft.AspNetCore.Razor.Language.Extensions
+{
+    public class SectionTargetExtensionTest
+    {
+        [Fact]
+        public void WriteSection_WritesSectionCode()
+        {
+            // Arrange
+            var node = new SectionIRNode()
+            {
+                Name = "MySection"
+            };
+
+            var extension = new SectionTargetExtension()
+            {
+                SectionMethodName = "CreateSection"
+            };
+
+            var context = new CSharpRenderingContext()
+            { 
+                BasicWriter = new RuntimeBasicWriter(),
+                TagHelperWriter = new RuntimeTagHelperWriter(),
+                Writer = new CSharpCodeWriter(),
+                Options = RazorCodeGenerationOptions.CreateDefault(),
+            };
+
+            context.RenderChildren = (n) =>
+            {
+                Assert.Same(node, n);
+                context.Writer.WriteLine(" var s = \"Inside\"");
+            };
+
+            // Act
+            extension.WriteSection(context, node);
+
+            // Assert
+            var expected = @"CreateSection(""MySection"", async() => {
+     var s = ""Inside""
+}
+);
+";
+
+            var output = context.Writer.Builder.ToString();
+            Assert.Equal(expected, output);
+        }
+
+        [Fact]
+        public void WriteSection_WritesSectionCode_DesignTime()
+        {
+            // Arrange
+            var node = new SectionIRNode()
+            {
+                Name = "MySection"
+            };
+
+            var extension = new SectionTargetExtension()
+            {
+                SectionMethodName = "CreateSection"
+            };
+
+            var context = new CSharpRenderingContext()
+            {
+                BasicWriter = new RuntimeBasicWriter(),
+                TagHelperWriter = new RuntimeTagHelperWriter(),
+                Writer = new CSharpCodeWriter(),
+                Options = RazorCodeGenerationOptions.Create(false, 4, true, false),
+            };
+
+            context.RenderChildren = (n) =>
+            {
+                Assert.Same(node, n);
+                context.Writer.WriteLine(" var s = \"Inside\"");
+            };
+
+            // Act
+            extension.WriteSection(context, node);
+
+            // Assert
+            var expected = @"CreateSection(""MySection"", async(__razor_section_writer) => {
+     var s = ""Inside""
+}
+);
+";
+
+            var output = context.Writer.Builder.ToString();
+            Assert.Equal(expected, output);
+        }
+    }
+}

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime_DesignTime.codegen.cs

@@ -49,13 +49,14 @@ __o = Foo(item => new Template(async(__razor_template_writer) => {
 
 #line default
 #line hidden
-            DefineSection("Footer", async (__razor_section_writer) => {
+            DefineSection("Footer", async(__razor_section_writer) => {
 #line 14 "TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime.cshtml"
 __o = bar;
 
 #line default
 #line hidden
-            });
+            }
+            );
         }
         #pragma warning restore 1998
     }

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime_DesignTime.ir.txt

@@ -46,8 +46,7 @@ Document -
                     RazorIRToken - (154:8,26 [2] DesignTime.cshtml) - Html - \n
                     RazorIRToken - (156:9,0 [4] DesignTime.cshtml) - Html - </p>
                     RazorIRToken - (160:9,4 [4] DesignTime.cshtml) - Html - \n\n
-                CSharpCode - 
+                Section -  - Footer
-                    RazorIRToken -  - CSharp - DefineSection("Footer", async (__razor_section_writer) => {
                     HtmlContent - (181:11,17 [22] DesignTime.cshtml)
                         RazorIRToken - (181:11,17 [6] DesignTime.cshtml) - Html - \n    
                         RazorIRToken - (187:12,4 [3] DesignTime.cshtml) - Html - <p>
@@ -58,5 +57,3 @@ Document -
                         RazorIRToken - (204:13,5 [3] DesignTime.cshtml) - CSharp - bar
                     HtmlContent - (207:13,8 [2] DesignTime.cshtml)
                         RazorIRToken - (207:13,8 [2] DesignTime.cshtml) - Html - \n
-                CSharpCode - 
-                    RazorIRToken -  - CSharp - });

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime_DesignTime.mappings.txt

@@ -44,6 +44,6 @@ Generated Location: (1508:47,1 [1] )
 
 Source Location: (204:13,5 [3] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime.cshtml)
 |bar|
-Generated Location: (1709:53,6 [3] )
+Generated Location: (1708:53,6 [3] )
 |bar|
 

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.codegen.cs

@@ -29,16 +29,18 @@ global::System.Object NestedDelegates = null;
 
 #line default
 #line hidden
-            DefineSection("Section2", async (__razor_section_writer) => {
+            DefineSection("Section2", async(__razor_section_writer) => {
 #line 8 "TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml"
                 __o = thing;
 
 #line default
 #line hidden
-            });
+            }
-            DefineSection("Section1", async (__razor_section_writer) => {
+            );
-            });
+            DefineSection("Section1", async(__razor_section_writer) => {
-            DefineSection("NestedDelegates", async (__razor_section_writer) => {
+            }
+            );
+            DefineSection("NestedDelegates", async(__razor_section_writer) => {
 #line 16 "TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml"
        Func<dynamic, object> f = 
 
@@ -57,7 +59,8 @@ global::System.Object NestedDelegates = null;
 
 #line default
 #line hidden
-            });
+            }
+            );
         }
         #pragma warning restore 1998
     }

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.ir.txt

@@ -14,8 +14,7 @@ Document -
                     RazorIRToken - (49:3,0 [2] Sections.cshtml) - Html - \n
                     RazorIRToken - (51:4,0 [5] Sections.cshtml) - Html - <div>
                     RazorIRToken - (56:4,5 [24] Sections.cshtml) - Html - This is in the Body>\n\n
-                CSharpCode - 
+                Section -  - Section2
-                    RazorIRToken -  - CSharp - DefineSection("Section2", async (__razor_section_writer) => {
                     HtmlContent - (99:6,19 [10] Sections.cshtml)
                         RazorIRToken - (99:6,19 [6] Sections.cshtml) - Html - \n    
                         RazorIRToken - (105:7,4 [4] Sections.cshtml) - Html - <div
@@ -29,24 +28,18 @@ Document -
                         RazorIRToken - (130:7,29 [20] Sections.cshtml) - Html - This is in Section 2
                         RazorIRToken - (150:7,49 [6] Sections.cshtml) - Html - </div>
                         RazorIRToken - (156:7,55 [2] Sections.cshtml) - Html - \n
-                CSharpCode - 
-                    RazorIRToken -  - CSharp - });
                 HtmlContent - (159:8,1 [4] Sections.cshtml)
                     RazorIRToken - (159:8,1 [4] Sections.cshtml) - Html - \n\n
-                CSharpCode - 
+                Section -  - Section1
-                    RazorIRToken -  - CSharp - DefineSection("Section1", async (__razor_section_writer) => {
                     HtmlContent - (182:10,19 [39] Sections.cshtml)
                         RazorIRToken - (182:10,19 [6] Sections.cshtml) - Html - \n    
                         RazorIRToken - (188:11,4 [5] Sections.cshtml) - Html - <div>
                         RazorIRToken - (193:11,9 [20] Sections.cshtml) - Html - This is in Section 1
                         RazorIRToken - (213:11,29 [6] Sections.cshtml) - Html - </div>
                         RazorIRToken - (219:11,35 [2] Sections.cshtml) - Html - \n
-                CSharpCode - 
-                    RazorIRToken -  - CSharp - });
                 HtmlContent - (222:12,1 [4] Sections.cshtml)
                     RazorIRToken - (222:12,1 [4] Sections.cshtml) - Html - \n\n
-                CSharpCode - 
+                Section -  - NestedDelegates
-                    RazorIRToken -  - CSharp - DefineSection("NestedDelegates", async (__razor_section_writer) => {
                     HtmlContent - (252:14,26 [6] Sections.cshtml)
                         RazorIRToken - (252:14,26 [6] Sections.cshtml) - Html - \n    
                     CSharpCode - (260:15,6 [27] Sections.cshtml)
@@ -60,5 +53,3 @@ Document -
                             RazorIRToken - (299:15,45 [7] Sections.cshtml) - Html - </span>
                     CSharpCode - (306:15,52 [2] Sections.cshtml)
                         RazorIRToken - (306:15,52 [2] Sections.cshtml) - CSharp - ; 
-                CSharpCode - 
-                    RazorIRToken -  - CSharp - });

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.mappings.txt

@@ -24,21 +24,21 @@ Generated Location: (896:26,2 [44] )
 
 Source Location: (123:7,22 [5] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml)
 |thing|
-Generated Location: (1152:33,22 [5] )
+Generated Location: (1151:33,22 [5] )
 |thing|
 
 Source Location: (260:15,6 [27] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml)
 | Func<dynamic, object> f = |
-Generated Location: (1473:42,6 [27] )
+Generated Location: (1498:44,6 [27] )
 | Func<dynamic, object> f = |
 
 Source Location: (295:15,41 [4] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml)
 |item|
-Generated Location: (1729:48,41 [4] )
+Generated Location: (1758:50,41 [4] )
 |item|
 
 Source Location: (306:15,52 [2] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml)
 |; |
-Generated Location: (1934:55,52 [2] )
+Generated Location: (1971:57,52 [2] )
 |; |
 

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_Runtime.codegen.cs

@@ -14,7 +14,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests.TestFiles
 #line default
 #line hidden
             WriteLiteral("\r\n<div>This is in the Body>\r\n\r\n");
-            DefineSection("Section2", async () => {
+            DefineSection("Section2", async() => {
                 WriteLiteral("\r\n    <div");
                 BeginWriteAttribute("class", " class=\"", 109, "\"", 128, 2);
                 WriteAttributeValue("", 117, "some", 117, 4, true);
@@ -25,13 +25,15 @@ WriteAttributeValue(" ", 121, thing, 122, 6, false);
 #line hidden
                 EndWriteAttribute();
                 WriteLiteral(">This is in Section 2</div>\r\n");
-            });
+            }
+            );
             WriteLiteral("\r\n");
-            DefineSection("Section1", async () => {
+            DefineSection("Section1", async() => {
                 WriteLiteral("\r\n    <div>This is in Section 1</div>\r\n");
-            });
+            }
+            );
             WriteLiteral("\r\n");
-            DefineSection("NestedDelegates", async () => {
+            DefineSection("NestedDelegates", async() => {
                 WriteLiteral("\r\n");
 #line 16 "TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml"
        Func<dynamic, object> f = 
@@ -55,7 +57,8 @@ WriteAttributeValue(" ", 121, thing, 122, 6, false);
 
 #line default
 #line hidden
-            });
+            }
+            );
         }
         #pragma warning restore 1998
     }

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_Runtime.ir.txt

@@ -8,8 +8,7 @@ Document -
                     RazorIRToken - (49:3,0 [2] Sections.cshtml) - Html - \n
                     RazorIRToken - (51:4,0 [5] Sections.cshtml) - Html - <div>
                     RazorIRToken - (56:4,5 [24] Sections.cshtml) - Html - This is in the Body>\n\n
-                CSharpCode - 
+                Section -  - Section2
-                    RazorIRToken -  - CSharp - DefineSection("Section2", async () => {
                     HtmlContent - (99:6,19 [10] Sections.cshtml)
                         RazorIRToken - (99:6,19 [6] Sections.cshtml) - Html - \n    
                         RazorIRToken - (105:7,4 [4] Sections.cshtml) - Html - <div
@@ -23,24 +22,18 @@ Document -
                         RazorIRToken - (130:7,29 [20] Sections.cshtml) - Html - This is in Section 2
                         RazorIRToken - (150:7,49 [6] Sections.cshtml) - Html - </div>
                         RazorIRToken - (156:7,55 [2] Sections.cshtml) - Html - \n
-                CSharpCode - 
-                    RazorIRToken -  - CSharp - });
                 HtmlContent - (161:9,0 [2] Sections.cshtml)
                     RazorIRToken - (161:9,0 [2] Sections.cshtml) - Html - \n
-                CSharpCode - 
+                Section -  - Section1
-                    RazorIRToken -  - CSharp - DefineSection("Section1", async () => {
                     HtmlContent - (182:10,19 [39] Sections.cshtml)
                         RazorIRToken - (182:10,19 [6] Sections.cshtml) - Html - \n    
                         RazorIRToken - (188:11,4 [5] Sections.cshtml) - Html - <div>
                         RazorIRToken - (193:11,9 [20] Sections.cshtml) - Html - This is in Section 1
                         RazorIRToken - (213:11,29 [6] Sections.cshtml) - Html - </div>
                         RazorIRToken - (219:11,35 [2] Sections.cshtml) - Html - \n
-                CSharpCode - 
-                    RazorIRToken -  - CSharp - });
                 HtmlContent - (224:13,0 [2] Sections.cshtml)
                     RazorIRToken - (224:13,0 [2] Sections.cshtml) - Html - \n
-                CSharpCode - 
+                Section -  - NestedDelegates
-                    RazorIRToken -  - CSharp - DefineSection("NestedDelegates", async () => {
                     HtmlContent - (252:14,26 [2] Sections.cshtml)
                         RazorIRToken - (252:14,26 [2] Sections.cshtml) - Html - \n
                     CSharpCode - (254:15,0 [4] Sections.cshtml)
@@ -56,5 +49,3 @@ Document -
                             RazorIRToken - (299:15,45 [7] Sections.cshtml) - Html - </span>
                     CSharpCode - (306:15,52 [2] Sections.cshtml)
                         RazorIRToken - (306:15,52 [2] Sections.cshtml) - CSharp - ; 
-                CSharpCode - 
-                    RazorIRToken -  - CSharp - });

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/StringLiterals_DesignTime.codegen.cs

@@ -19,10 +19,12 @@ global::System.Object WriteLiteralsToInHereAlso = null;
         #pragma warning disable 1998
         public async System.Threading.Tasks.Task ExecuteAsync()
         {
-            DefineSection("WriteLiteralsToInHere", async (__razor_section_writer) => {
+            DefineSection("WriteLiteralsToInHere", async(__razor_section_writer) => {
-            });
+            }
-            DefineSection("WriteLiteralsToInHereAlso", async (__razor_section_writer) => {
+            );
-            });
+            DefineSection("WriteLiteralsToInHereAlso", async(__razor_section_writer) => {
+            }
+            );
         }
         #pragma warning restore 1998
     }

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/StringLiterals_DesignTime.ir.txt

@@ -345,8 +345,7 @@ Document -
                     RazorIRToken - (2001:83,18 [4] StringLiterals.cshtml) - Html - </p>
                     RazorIRToken - (2005:83,22 [4] StringLiterals.cshtml) - Html - <br>
                     RazorIRToken - (2009:83,26 [4] StringLiterals.cshtml) - Html - \n\n
-                CSharpCode - 
+                Section -  - WriteLiteralsToInHere
-                    RazorIRToken -  - CSharp - DefineSection("WriteLiteralsToInHere", async (__razor_section_writer) => {
                     HtmlContent - (2045:85,32 [2618] StringLiterals.cshtml)
                         RazorIRToken - (2045:85,32 [6] StringLiterals.cshtml) - Html - \n    
                         RazorIRToken - (2051:86,4 [3] StringLiterals.cshtml) - Html - <p>
@@ -649,8 +648,6 @@ Document -
                         RazorIRToken - (4635:160,7 [22] StringLiterals.cshtml) - Html - This is line 75 nested
                         RazorIRToken - (4657:160,29 [4] StringLiterals.cshtml) - Html - </p>
                         RazorIRToken - (4661:160,33 [2] StringLiterals.cshtml) - Html - \n
-                CSharpCode - 
-                    RazorIRToken -  - CSharp - });
                 HtmlContent - (4664:161,1 [1028] StringLiterals.cshtml)
                     RazorIRToken - (4664:161,1 [2] StringLiterals.cshtml) - Html - \n
                     RazorIRToken - (4666:162,0 [3] StringLiterals.cshtml) - Html - <p>
@@ -825,8 +822,7 @@ Document -
                     RazorIRToken - (5668:204,3 [15] StringLiterals.cshtml) - Html - This is line 43
                     RazorIRToken - (5683:204,18 [4] StringLiterals.cshtml) - Html - </p>
                     RazorIRToken - (5687:204,22 [5] StringLiterals.cshtml) - Html - hi!\n
-                CSharpCode - 
+                Section -  - WriteLiteralsToInHereAlso
-                    RazorIRToken -  - CSharp - DefineSection("WriteLiteralsToInHereAlso", async (__razor_section_writer) => {
                     HtmlContent - (5728:205,36 [1023] StringLiterals.cshtml)
                         RazorIRToken - (5728:205,36 [6] StringLiterals.cshtml) - Html - \n    
                         RazorIRToken - (5734:206,4 [3] StringLiterals.cshtml) - Html - <p>
@@ -949,7 +945,5 @@ Document -
                         RazorIRToken - (6743:235,7 [2] StringLiterals.cshtml) - Html - 30
                         RazorIRToken - (6745:235,9 [4] StringLiterals.cshtml) - Html - </p>
                         RazorIRToken - (6749:235,13 [2] StringLiterals.cshtml) - Html - \n
-                CSharpCode - 
-                    RazorIRToken -  - CSharp - });
                 HtmlContent - (6752:236,1 [1] StringLiterals.cshtml)
                     RazorIRToken - (6752:236,1 [1] StringLiterals.cshtml) - Html - !

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/StringLiterals_Runtime.codegen.cs

@@ -94,7 +94,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests.TestFiles
 <p>This is line 84</p><br>
 
 ");
-            DefineSection("WriteLiteralsToInHere", async () => {
+            DefineSection("WriteLiteralsToInHere", async() => {
                 WriteLiteral(@"
     <p>This is line 1 nested</p>
     <p>This is line 2 nested</p>
@@ -174,7 +174,8 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests.TestFiles
     <p>This is line 74 nested</p>
     <p>This is line 75 nested</p>
 ");
-            });
+            }
+            );
             WriteLiteral(@"<p>This is line 1</p>
 <p>This is line 2</p>
 <p>This is line 3</p>
@@ -219,7 +220,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests.TestFiles
 <p>This is line 42</p>
 <p>This is line 43</p>hi!");
             WriteLiteral("\r\n");
-            DefineSection("WriteLiteralsToInHereAlso", async () => {
+            DefineSection("WriteLiteralsToInHereAlso", async() => {
                 WriteLiteral(@"
     <p>This is line 1 nested</p>
     <p>This is line 2 nested</p>
@@ -252,7 +253,8 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests.TestFiles
     <p>This is line 29 nested</p>
     <p>30</p>
 ");
-            });
+            }
+            );
             WriteLiteral("!");
         }
         #pragma warning restore 1998

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/StringLiterals_Runtime.ir.txt

@@ -340,8 +340,7 @@ Document -
                     RazorIRToken - (2001:83,18 [4] StringLiterals.cshtml) - Html - </p>
                     RazorIRToken - (2005:83,22 [4] StringLiterals.cshtml) - Html - <br>
                     RazorIRToken - (2009:83,26 [4] StringLiterals.cshtml) - Html - \n\n
-                CSharpCode - 
+                Section -  - WriteLiteralsToInHere
-                    RazorIRToken -  - CSharp - DefineSection("WriteLiteralsToInHere", async () => {
                     HtmlContent - (2045:85,32 [2618] StringLiterals.cshtml)
                         RazorIRToken - (2045:85,32 [6] StringLiterals.cshtml) - Html - \n    
                         RazorIRToken - (2051:86,4 [3] StringLiterals.cshtml) - Html - <p>
@@ -644,8 +643,6 @@ Document -
                         RazorIRToken - (4635:160,7 [22] StringLiterals.cshtml) - Html - This is line 75 nested
                         RazorIRToken - (4657:160,29 [4] StringLiterals.cshtml) - Html - </p>
                         RazorIRToken - (4661:160,33 [2] StringLiterals.cshtml) - Html - \n
-                CSharpCode - 
-                    RazorIRToken -  - CSharp - });
                 HtmlContent - (4666:162,0 [1026] StringLiterals.cshtml)
                     RazorIRToken - (4666:162,0 [3] StringLiterals.cshtml) - Html - <p>
                     RazorIRToken - (4669:162,3 [14] StringLiterals.cshtml) - Html - This is line 1
@@ -819,8 +816,7 @@ Document -
                     RazorIRToken - (5668:204,3 [15] StringLiterals.cshtml) - Html - This is line 43
                     RazorIRToken - (5683:204,18 [4] StringLiterals.cshtml) - Html - </p>
                     RazorIRToken - (5687:204,22 [5] StringLiterals.cshtml) - Html - hi!\n
-                CSharpCode - 
+                Section -  - WriteLiteralsToInHereAlso
-                    RazorIRToken -  - CSharp - DefineSection("WriteLiteralsToInHereAlso", async () => {
                     HtmlContent - (5728:205,36 [1023] StringLiterals.cshtml)
                         RazorIRToken - (5728:205,36 [6] StringLiterals.cshtml) - Html - \n    
                         RazorIRToken - (5734:206,4 [3] StringLiterals.cshtml) - Html - <p>
@@ -943,7 +939,5 @@ Document -
                         RazorIRToken - (6743:235,7 [2] StringLiterals.cshtml) - Html - 30
                         RazorIRToken - (6745:235,9 [4] StringLiterals.cshtml) - Html - </p>
                         RazorIRToken - (6749:235,13 [2] StringLiterals.cshtml) - Html - \n
-                CSharpCode - 
-                    RazorIRToken -  - CSharp - });
                 HtmlContent - (6752:236,1 [1] StringLiterals.cshtml)
                     RazorIRToken - (6752:236,1 [1] StringLiterals.cshtml) - Html - !

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/TagHelpersInSection_Runtime.codegen.cs

@@ -35,7 +35,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests.TestFiles
 #line default
 #line hidden
             WriteLiteral("\r\n");
-            DefineSection("MySection", async () => {
+            DefineSection("MySection", async() => {
                 WriteLiteral("\r\n    <div>\r\n        ");
                 __tagHelperExecutionContext = __tagHelperScopeManager.Begin("mytaghelper", global::Microsoft.AspNetCore.Razor.TagHelpers.TagMode.StartTagAndEndTag, "test", async() => {
                     WriteLiteral("\r\n            In None ContentBehavior.\r\n            ");
@@ -89,7 +89,8 @@ AddHtmlAttributeValue(" ", 201, DateTime.Now, 202, 13, false);
                 Write(__tagHelperExecutionContext.Output);
                 __tagHelperExecutionContext = __tagHelperScopeManager.End();
                 WriteLiteral("\r\n    </div>\r\n");
-            });
+            }
+            );
         }
         #pragma warning restore 1998
     }

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/TagHelpersInSection_Runtime.ir.txt

@@ -9,8 +9,7 @@ Document -
                     RazorIRToken - (37:2,2 [31] TagHelpersInSection.cshtml) - CSharp - \n    var code = "some code";\n
                 HtmlContent - (71:5,0 [2] TagHelpersInSection.cshtml)
                     RazorIRToken - (71:5,0 [2] TagHelpersInSection.cshtml) - Html - \n
-                CSharpCode - 
+                Section -  - MySection
-                    RazorIRToken -  - CSharp - DefineSection("MySection", async () => {
                     HtmlContent - (93:6,20 [21] TagHelpersInSection.cshtml)
                         RazorIRToken - (93:6,20 [6] TagHelpersInSection.cshtml) - Html - \n    
                         RazorIRToken - (99:7,4 [5] TagHelpersInSection.cshtml) - Html - <div>
@@ -47,5 +46,3 @@ Document -
                         RazorIRToken - (359:11,22 [6] TagHelpersInSection.cshtml) - Html - \n    
                         RazorIRToken - (365:12,4 [6] TagHelpersInSection.cshtml) - Html - </div>
                         RazorIRToken - (371:12,10 [2] TagHelpersInSection.cshtml) - Html - \n
-                CSharpCode - 
-                    RazorIRToken -  - CSharp - });

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

@@ -6,13 +6,14 @@ using System.IO;
 using System.Linq;
 using System.Security.Cryptography;
 using System.Text;
+using Microsoft.AspNetCore.Razor.Language.Extensions;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
 using Microsoft.AspNetCore.Razor.Language.Legacy;
 
 namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
 {
     // Serializes single IR nodes (shallow).
-    public class RazorIRNodeWriter : RazorIRNodeVisitor
+    public class RazorIRNodeWriter : RazorIRNodeVisitor, IExtensionIRNodeVisitor<SectionIRNode>
     {
         private readonly TextWriter _writer;
 
@@ -130,6 +131,11 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
             }
         }
 
+        public void VisitExtension(SectionIRNode node)
+        {
+            WriteContentNode(node, node.Name);
+        }
+
         protected void WriteBasicNode(RazorIRNode node)
         {
             WriteIndent();