Fix @section directive incorrectly allowed in .razor files

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/SectionDirectivePassTest.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Linq;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
 using Xunit;
 using static Microsoft.AspNetCore.Razor.Language.Intermediate.IntermediateNodeAssert;
@@ -76,4 +77,47 @@ public void Execute_WrapsStatementInSectionNode()
         Assert.Equal("Header", section.SectionName);
         Children(section, c => Html(" <p>Hello World</p> ", c));
     }
+
+    [Fact]
+    public void SectionDirective_IsRecognizedInLegacyFiles()
+    {
+        // Arrange
+        var content = "@section Header { <p>Hello World</p> }";
+        var source = TestRazorSourceDocument.Create(content, filePath: "test.cshtml", relativePath: "test.cshtml");
+
+        // Act
+        var codeDocument = ProjectEngine.CreateCodeDocument(source, RazorFileKind.Legacy);
+        ProjectEngine.Engine.Process(codeDocument);
+
+        // Assert
+        var syntaxTree = codeDocument.GetSyntaxTree();
+        Assert.NotNull(syntaxTree);
+
+        // The section directive should be recognized without errors
+        var diagnostics = syntaxTree.Diagnostics;
+        Assert.Empty(diagnostics);
+    }
+
+    [Fact]
+    public void SectionDirective_IsNotRecognizedInComponentFiles()
+    {
+        // Arrange
+        var content = "@section Header { <p>Hello World</p> }";
+        var source = TestRazorSourceDocument.Create(content, filePath: "test.razor", relativePath: "test.razor");
+
+        // Act
+        var codeDocument = ProjectEngine.CreateCodeDocument(source, RazorFileKind.Component);
+        ProjectEngine.Engine.Process(codeDocument);
+
+        // Assert
+        var syntaxTree = codeDocument.GetSyntaxTree();
+        Assert.NotNull(syntaxTree);
+
+        // The section directive should NOT be recognized in component files.
+        // Verify that no RazorDirective node for 'section' exists in the syntax tree
+        var directiveNodes = syntaxTree.Root.DescendantNodes()
+            .OfType<Microsoft.AspNetCore.Razor.Language.Syntax.RazorDirectiveSyntax>();
+
+        Assert.DoesNotContain(directiveNodes, d => d.DirectiveDescriptor?.Directive == "section");
+    }
 }

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/CSharpSectionTest.cs

@@ -300,5 +300,4 @@ public void _WithDoubleTransition2()
     {
         ParseDocumentTest("@section s {<span foo='@DateTime.Now @@' />}", [SectionDirective.Directive]);
     }
-
 }

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Extensions/SectionDirective.cs

@@ -26,7 +26,7 @@ public static void Register(RazorProjectEngineBuilder builder)
             throw new ArgumentNullException(nameof(builder));
         }
 
-        builder.AddDirective(Directive, RazorFileKind.Legacy, RazorFileKind.Component);
+        builder.AddDirective(Directive, RazorFileKind.Legacy);
         builder.Features.Add(new SectionDirectivePass());
         builder.AddTargetExtension(new SectionTargetExtension());
     }