diff --git a/src/Microsoft.AspNetCore.Razor.Language/Extensions/SectionTargetExtension.cs b/src/Microsoft.AspNetCore.Razor.Language/Extensions/SectionTargetExtension.cs
index 5e47ca17d7..e99c1598f3 100644
--- a/src/Microsoft.AspNetCore.Razor.Language/Extensions/SectionTargetExtension.cs
+++ b/src/Microsoft.AspNetCore.Razor.Language/Extensions/SectionTargetExtension.cs
@@ -7,6 +7,9 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
 {
     public sealed class SectionTargetExtension : ISectionTargetExtension
     {
+        // Compatibility for 1.X projects
+        private const string DefaultWriterName = "__razor_section_writer";
+
         public static readonly string DefaultSectionMethodName = "DefineSection";
 
         public string SectionMethodName { get; set; } = DefaultSectionMethodName;
@@ -19,7 +22,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
                 .Write(node.SectionName)
                 .Write("\", ");
 
-            using (context.CodeWriter.BuildAsyncLambda())
+            using (context.CodeWriter.BuildAsyncLambda(DefaultWriterName))
             {
                 context.RenderChildren(node);
             }
diff --git a/test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.codegen.cs b/test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.codegen.cs
index d0551e4366..fd3c971a71 100644
--- a/test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.codegen.cs
+++ b/test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.codegen.cs
@@ -42,7 +42,7 @@ global::System.Object Section1 = null;
 
 #line default
 #line hidden
-            DefineSection("Section1", async() => {
+            DefineSection("Section1", async(__razor_section_writer) => {
                 __InputTestTagHelper = CreateTagHelper<global::InputTestTagHelper>();
 #line 13 "TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml"
 __InputTestTagHelper.For = ModelExpressionProvider.CreateModelExpression(ViewData, __model => __model.Date);
diff --git a/test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.mappings.txt b/test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.mappings.txt
index c2b3302c4d..5e120c830d 100644
--- a/test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.mappings.txt
+++ b/test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.mappings.txt
@@ -24,6 +24,6 @@ Generated Location: (1432:39,2 [46] )
 
 Source Location: (222:12,21 [4] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml)
 |Date|
-Generated Location: (1835:47,102 [4] )
+Generated Location: (1857:47,102 [4] )
 |Date|
 
diff --git a/test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_Runtime.codegen.cs b/test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_Runtime.codegen.cs
index ba56f04308..95aa1a96a8 100644
--- a/test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_Runtime.codegen.cs
+++ b/test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_Runtime.codegen.cs
@@ -51,7 +51,7 @@ namespace AspNetCore
             BeginContext(117, 26, true);
             WriteLiteral("\r\n<div>Some body</div>\r\n\r\n");
             EndContext();
-            DefineSection("Section1", async() => {
+            DefineSection("Section1", async(__razor_section_writer) => {
                 BeginContext(162, 43, true);
                 WriteLiteral("\r\n    <div>This is in Section 1</div>\r\n    ");
                 EndContext();
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/SectionTargetExtensionTest.cs b/test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/SectionTargetExtensionTest.cs
index c369432e3b..bfeb71ffb7 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/SectionTargetExtensionTest.cs
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/SectionTargetExtensionTest.cs
@@ -33,7 +33,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
             extension.WriteSection(context, node);
 
             // Assert
-            var expected = @"CreateSection(""MySection"", async() => {
+            var expected = @"CreateSection(""MySection"", async(__razor_section_writer) => {
     Render Children
 }
 );
@@ -67,7 +67,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
             extension.WriteSection(context, node);
 
             // Assert
-            var expected = @"CreateSection(""MySection"", async() => {
+            var expected = @"CreateSection(""MySection"", async(__razor_section_writer) => {
     Render Children
 }
 );
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime_DesignTime.codegen.cs b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime_DesignTime.codegen.cs
index 0897ae157d..d30aea4b02 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime_DesignTime.codegen.cs
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime_DesignTime.codegen.cs
@@ -53,7 +53,7 @@ __o = Foo(item => new Template(async(__razor_template_writer) => {
 
 #line default
 #line hidden
-            DefineSection("Footer", async() => {
+            DefineSection("Footer", async(__razor_section_writer) => {
 #line 14 "TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime.cshtml"
 __o = bar;
 
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime_DesignTime.mappings.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime_DesignTime.mappings.txt
index a72db81cb6..87ab943dfc 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime_DesignTime.mappings.txt
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime_DesignTime.mappings.txt
@@ -44,6 +44,6 @@ Generated Location: (1636:51,1 [1] )
 
 Source Location: (204:13,5 [3] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/DesignTime.cshtml)
 |bar|
-Generated Location: (1814:57,6 [3] )
+Generated Location: (1836:57,6 [3] )
 |bar|
 
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.codegen.cs b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.codegen.cs
index b610f02553..556cf5e489 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.codegen.cs
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.codegen.cs
@@ -33,7 +33,7 @@ global::System.Object NestedDelegates = null;
 
 #line default
 #line hidden
-            DefineSection("Section2", async() => {
+            DefineSection("Section2", async(__razor_section_writer) => {
 #line 8 "TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml"
                 __o = thing;
 
@@ -41,10 +41,10 @@ global::System.Object NestedDelegates = null;
 #line hidden
             }
             );
-            DefineSection("Section1", async() => {
+            DefineSection("Section1", async(__razor_section_writer) => {
             }
             );
-            DefineSection("NestedDelegates", async() => {
+            DefineSection("NestedDelegates", async(__razor_section_writer) => {
 #line 16 "TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml"
        Func<dynamic, object> f = 
 
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.mappings.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.mappings.txt
index ff1262a84a..f6aedef836 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.mappings.txt
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_DesignTime.mappings.txt
@@ -24,21 +24,21 @@ Generated Location: (1024:30,2 [44] )
 
 Source Location: (123:7,22 [5] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml)
 |thing|
-Generated Location: (1257:37,22 [5] )
+Generated Location: (1279:37,22 [5] )
 |thing|
 
 Source Location: (260:15,6 [27] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml)
 | Func<dynamic, object> f = |
-Generated Location: (1560:48,6 [27] )
+Generated Location: (1626:48,6 [27] )
 | Func<dynamic, object> f = |
 
 Source Location: (295:15,41 [4] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml)
 |item|
-Generated Location: (1820:54,41 [4] )
+Generated Location: (1886:54,41 [4] )
 |item|
 
 Source Location: (306:15,52 [2] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml)
 |; |
-Generated Location: (2033:61,52 [2] )
+Generated Location: (2099:61,52 [2] )
 |; |
 
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_Runtime.codegen.cs b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_Runtime.codegen.cs
index 128b60701f..179aa5c3d8 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_Runtime.codegen.cs
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections_Runtime.codegen.cs
@@ -16,7 +16,7 @@ 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(__razor_section_writer) => {
                 WriteLiteral("\r\n    <div");
                 BeginWriteAttribute("class", " class=\"", 109, "\"", 128, 2);
                 WriteAttributeValue("", 117, "some", 117, 4, true);
@@ -30,12 +30,12 @@ WriteAttributeValue(" ", 121, thing, 122, 6, false);
             }
             );
             WriteLiteral("\r\n");
-            DefineSection("Section1", async() => {
+            DefineSection("Section1", async(__razor_section_writer) => {
                 WriteLiteral("\r\n    <div>This is in Section 1</div>\r\n");
             }
             );
             WriteLiteral("\r\n");
-            DefineSection("NestedDelegates", async() => {
+            DefineSection("NestedDelegates", async(__razor_section_writer) => {
                 WriteLiteral("\r\n");
 #line 16 "TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Sections.cshtml"
        Func<dynamic, object> f = 
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/StringLiterals_DesignTime.codegen.cs b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/StringLiterals_DesignTime.codegen.cs
index 49a1737a04..e1a96c0d30 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/StringLiterals_DesignTime.codegen.cs
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/StringLiterals_DesignTime.codegen.cs
@@ -23,10 +23,10 @@ global::System.Object WriteLiteralsToInHereAlso = null;
         #pragma warning disable 1998
         public async System.Threading.Tasks.Task ExecuteAsync()
         {
-            DefineSection("WriteLiteralsToInHere", async() => {
+            DefineSection("WriteLiteralsToInHere", async(__razor_section_writer) => {
             }
             );
-            DefineSection("WriteLiteralsToInHereAlso", async() => {
+            DefineSection("WriteLiteralsToInHereAlso", async(__razor_section_writer) => {
             }
             );
         }
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/StringLiterals_Runtime.codegen.cs b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/StringLiterals_Runtime.codegen.cs
index ba174de703..e3770e0570 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/StringLiterals_Runtime.codegen.cs
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/StringLiterals_Runtime.codegen.cs
@@ -96,7 +96,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests.TestFiles
 <p>This is line 84</p><br>
 
 ");
-            DefineSection("WriteLiteralsToInHere", async() => {
+            DefineSection("WriteLiteralsToInHere", async(__razor_section_writer) => {
                 WriteLiteral(@"
     <p>This is line 1 nested</p>
     <p>This is line 2 nested</p>
@@ -222,7 +222,7 @@ 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(__razor_section_writer) => {
                 WriteLiteral(@"
     <p>This is line 1 nested</p>
     <p>This is line 2 nested</p>
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/TagHelpersInSection_Runtime.codegen.cs b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/TagHelpersInSection_Runtime.codegen.cs
index 1d3fbf2f83..d8924cbaab 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/TagHelpersInSection_Runtime.codegen.cs
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/TagHelpersInSection_Runtime.codegen.cs
@@ -37,7 +37,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests.TestFiles
 #line default
 #line hidden
             WriteLiteral("\r\n");
-            DefineSection("MySection", async() => {
+            DefineSection("MySection", async(__razor_section_writer) => {
                 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            ");
diff --git a/test/Microsoft.AspNetCore.Razor.Test.MvcShim/Microsoft.AspNetCore.Mvc.Razor/RazorPageBase.cs b/test/Microsoft.AspNetCore.Razor.Test.MvcShim/Microsoft.AspNetCore.Mvc.Razor/RazorPageBase.cs
index d1568a8075..a4916e5378 100644
--- a/test/Microsoft.AspNetCore.Razor.Test.MvcShim/Microsoft.AspNetCore.Mvc.Razor/RazorPageBase.cs
+++ b/test/Microsoft.AspNetCore.Razor.Test.MvcShim/Microsoft.AspNetCore.Mvc.Razor/RazorPageBase.cs
@@ -83,6 +83,11 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             throw new NotImplementedException();
         }
 
+        // Compatibility for 1.X projects
+        protected void DefineSection(string name, Func<object, Task> section)
+        {
+        }
+
         public virtual void DefineSection(string name, RenderAsyncDelegate section)
         {
         }