Don't do any interesting mapping for Enc diagnostics in cohosting

src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/LanguageServer/RazorDiagnosticsBenchmark.cs

@@ -85,7 +85,7 @@ public void Setup()
         var documentMappingService = BuildRazorDocumentMappingService();
 
         var optionsMonitor = Mock.Of<RazorLSPOptionsMonitor>(MockBehavior.Strict);
-        var translateDiagnosticsService = new RazorTranslateDiagnosticsService(documentMappingService, loggerFactory);
+        var translateDiagnosticsService = new RazorTranslateDiagnosticsService(documentMappingService, languageServerFeatureOptions, loggerFactory);
         DocumentPullDiagnosticsEndpoint = new VSDocumentDiagnosticsEndpoint(translateDiagnosticsService, optionsMonitor, languageServer, telemetryReporter: null);
     }
 

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Diagnostics/RazorTranslateDiagnosticsService.cs

@@ -17,6 +17,7 @@
 using Microsoft.CodeAnalysis.Razor.Logging;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 using Microsoft.CodeAnalysis.Razor.Protocol;
+using Microsoft.CodeAnalysis.Razor.Workspaces;
 using Microsoft.CodeAnalysis.Text;
 
 namespace Microsoft.CodeAnalysis.Razor.Diagnostics;
@@ -28,13 +29,11 @@ namespace Microsoft.CodeAnalysis.Razor.Diagnostics;
 /// Contains several methods for mapping and filtering Razor and C# diagnostics. It allows for
 /// translating code diagnostics from one representation into another, such as from C# to Razor.
 /// </summary>
-/// <param name="documentMappingService">The <see cref="IDocumentMappingService"/>.</param>
-/// <param name="loggerFactory">The <see cref="ILoggerFactory"/>.</param>
-/// <exception cref="ArgumentNullException"/>
-internal class RazorTranslateDiagnosticsService(IDocumentMappingService documentMappingService, ILoggerFactory loggerFactory)
+internal class RazorTranslateDiagnosticsService(IDocumentMappingService documentMappingService, LanguageServerFeatureOptions featureOptions, ILoggerFactory loggerFactory)
 {
-    private readonly ILogger _logger = loggerFactory.GetOrCreateLogger<RazorTranslateDiagnosticsService>();
     private readonly IDocumentMappingService _documentMappingService = documentMappingService;
+    private readonly LanguageServerFeatureOptions _featureOptions = featureOptions;
+    private readonly ILogger _logger = loggerFactory.GetOrCreateLogger<RazorTranslateDiagnosticsService>();
 
     private static readonly FrozenSet<string> s_cSharpDiagnosticsToIgnore = new HashSet<string>(
     [
@@ -521,7 +520,8 @@ private static bool CheckIfDocumentHasRazorDiagnostic(RazorCodeDocument codeDocu
 
     private bool TryGetOriginalDiagnosticRange(LspDiagnostic diagnostic, RazorCodeDocument codeDocument, [NotNullWhen(true)] out LspRange? originalRange)
     {
-        if (IsRudeEditDiagnostic(diagnostic))
+        // In cohosting, Enc diagnostics aren't special
+        if (!_featureOptions.UseRazorCohostServer && IsRudeEditDiagnostic(diagnostic))
         {
             if (TryRemapRudeEditRange(diagnostic.Range, codeDocument, out originalRange))
             {
@@ -560,9 +560,9 @@ private static bool IsRudeEditDiagnostic(LspDiagnostic diagnostic)
 
     private bool TryRemapRudeEditRange(LspRange diagnosticRange, RazorCodeDocument codeDocument, [NotNullWhen(true)] out LspRange? remappedRange)
     {
-        // This is a rude edit diagnostic that has already been mapped to the Razor document. The mapping isn't absolutely correct though,
-        // it's based on the runtime code generation of the Razor document therefore we need to re-map the already mapped diagnostic in a
-        // semi-intelligent way.
+        // This is a rude edit diagnostic that has already been mapped to the Razor document if cohosting is off.
+        // The mapping isn't absolutely correct though, it's based on the runtime code generation of the Razor document
+        // therefore we need to re-map the already mapped diagnostic in a semi-intelligent way.
 
         var syntaxRoot = codeDocument.GetRequiredSyntaxRoot();
         var sourceText = codeDocument.Source.Text;

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/Diagnostics/RemoteRazorTranslateDiagnosticsService.cs

@@ -5,13 +5,15 @@
 using Microsoft.CodeAnalysis.Razor.Diagnostics;
 using Microsoft.CodeAnalysis.Razor.DocumentMapping;
 using Microsoft.CodeAnalysis.Razor.Logging;
+using Microsoft.CodeAnalysis.Razor.Workspaces;
 
 namespace Microsoft.CodeAnalysis.Remote.Razor.Diagnostics;
 
 [Export(typeof(RazorTranslateDiagnosticsService)), Shared]
 [method: ImportingConstructor]
 internal sealed class RemoteRazorTranslateDiagnosticsService(
     IDocumentMappingService documentMappingService,
-    ILoggerFactory loggerFactory) : RazorTranslateDiagnosticsService(documentMappingService, loggerFactory)
+    LanguageServerFeatureOptions featureOptions,
+    ILoggerFactory loggerFactory) : RazorTranslateDiagnosticsService(documentMappingService, featureOptions, loggerFactory)
 {
 }

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Diagnostics/DiagnosticsEndToEndTest.cs

@@ -84,7 +84,7 @@ private async Task ValidateDiagnosticsAsync(string input, string? filePath = nul
         var documentContext = CreateDocumentContext(uri, codeDocument);
         var requestContext = new RazorRequestContext(documentContext, null!, "lsp/method", uri: null);
 
-        var translateDiagnosticsService = new RazorTranslateDiagnosticsService(DocumentMappingService, LoggerFactory);
+        var translateDiagnosticsService = new RazorTranslateDiagnosticsService(DocumentMappingService, LanguageServerFeatureOptions, LoggerFactory);
         var optionsMonitor = TestRazorLSPOptionsMonitor.Create();
         var diagnosticsEndPoint = new DocumentDiagnosticsEndpoint(translateDiagnosticsService, languageServer, telemetryReporter: null);
 

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Diagnostics/VSCSharpDiagnosticsEndToEndTest.cs

@@ -83,7 +83,7 @@ private async Task ValidateDiagnosticsAsync(string input, string? filePath = nul
         var documentContext = CreateDocumentContext(uri, codeDocument);
         var requestContext = new RazorRequestContext(documentContext, null!, "lsp/method", uri: null);
 
-        var translateDiagnosticsService = new RazorTranslateDiagnosticsService(DocumentMappingService, LoggerFactory);
+        var translateDiagnosticsService = new RazorTranslateDiagnosticsService(DocumentMappingService, LanguageServerFeatureOptions, LoggerFactory);
         var optionsMonitor = TestRazorLSPOptionsMonitor.Create();
         var diagnosticsEndPoint = new VSDocumentDiagnosticsEndpoint(translateDiagnosticsService, optionsMonitor, languageServer, telemetryReporter: null);
 

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Diagnostics/VSDocumentDiagnosticsEndpointTest.cs

@@ -4,7 +4,9 @@
 using Microsoft.AspNetCore.Razor.LanguageServer.Diagnostics;
 using Microsoft.AspNetCore.Razor.LanguageServer.Hosting;
 using Microsoft.AspNetCore.Razor.Test.Common.LanguageServer;
+using Microsoft.AspNetCore.Razor.Test.Common.Workspaces;
 using Microsoft.CodeAnalysis.Razor.Diagnostics;
+using Microsoft.CodeAnalysis.Razor.Workspaces;
 using Moq;
 using Xunit;
 using Xunit.Abstractions;
@@ -17,9 +19,11 @@ public sealed class VSDocumentDiagnosticsEndpointTest(ITestOutputHelper testOutp
     public void ApplyCapabilities_AddsExpectedCapabilities()
     {
         // Arrange
+        var languageServerFeatureOptions = new TestLanguageServerFeatureOptions();
         var documentMappingService = new LspDocumentMappingService(FilePathService, new TestDocumentContextFactory(), LoggerFactory);
         var razorTranslate = new Mock<RazorTranslateDiagnosticsService>(MockBehavior.Strict,
             documentMappingService,
+            languageServerFeatureOptions,
             LoggerFactory);
         var optionsMonitor = TestRazorLSPOptionsMonitor.Create();
         var clientConnection = new Mock<IClientConnection>(MockBehavior.Strict);

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/SingleServerDelegatingEndpointTestBase.cs

@@ -57,7 +57,8 @@ private protected async Task<TestLanguageServer> CreateLanguageServerAsync(
         DocumentContextFactory = new TestDocumentContextFactory(razorFilePath, codeDocument);
 
         LanguageServerFeatureOptions = Mock.Of<LanguageServerFeatureOptions>(options =>
-            options.SupportsFileManipulation == true,
+            options.SupportsFileManipulation == true &&
+            options.UseRazorCohostServer == false,
             MockBehavior.Strict);
 
         DocumentMappingService = new LspDocumentMappingService(FilePathService, DocumentContextFactory, LoggerFactory);