C# Razor errors (inlay hint)

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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

I get these errors sometimes when editting Razor files in C#

2026-05-25 14:32:27.924 [info] [Error - 2:32:27 PM] [textDocument/inlayHint] [LanguageServerHost] System.ArgumentException: Range={ Start={ Line=12, Character=0 }, End={ Line=104, Character=0 } }. text.Length=2930. text.Lines.Count=100
 ---> System.ArgumentOutOfRangeException: The requested line number 104 must be less than the number of lines 100. (Parameter 'Line')
   at Microsoft.CodeAnalysis.Text.TextLineCollection.GetPosition(LinePosition position) in /_/src/Compilers/Core/Portable/Text/TextLineCollection.cs:line 67
   at Microsoft.CodeAnalysis.LanguageServer.ProtocolConversions.RangeToTextSpan(Range range, SourceText text) in /_/src/LanguageServer/Protocol/Extensions/ProtocolConversions.cs:line 306
   --- End of inner exception stack trace ---
   at Microsoft.CodeAnalysis.LanguageServer.ProtocolConversions.RangeToTextSpan(Range range, SourceText text) in /_/src/LanguageServer/Protocol/Extensions/ProtocolConversions.cs:line 311
   at Microsoft.CodeAnalysis.LanguageServer.Handler.InlayHint.InlayHintHandler.CalculateInlayHintsAsync(Document document, Range range, InlineHintsOptions options, Boolean displayAllOverride, CancellationToken cancellationToken) in /_/src/LanguageServer/Protocol/Handler/InlayHint/InlayHintHandler.cs:line 100
   at Microsoft.CodeAnalysis.LanguageServer.Handler.InlayHint.InlayHintHandler.GetInlayHintsAsync(Document document, TextDocumentIdentifier textDocumentIdentifier, Range range, InlineHintsOptions options, Boolean displayAllOverride, InlayHintCache inlayHintCache, CancellationToken cancellationToken) in /_/src/LanguageServer/Protocol/Handler/InlayHint/InlayHintHandler.cs:line 53
   at Microsoft.CommonLanguageServerProtocol.Framework.QueueItem`1.StartRequestAsync[TRequest,TResponse](TRequest request, TRequestContext context, IMethodHandler handler, String language, CancellationToken cancellationToken)
2026-05-25 14:32:27.924 [error] Error making textDocument/inlayHint request Range={ Start={ Line=12, Character=0 }, End={ Line=104, Character=0 } }. text.Length=2930. text.Lines.Count=100
2026-05-25 14:32:27.980 [info] [Error - 2:32:27 PM] [textDocument/semanticTokens/range] [LanguageServerHost] System.ArgumentOutOfRangeException: The requested line number 104 must be less than the number of lines 100. (Parameter 'Line')
   at Microsoft.CodeAnalysis.Text.TextLineCollection.GetPosition(LinePosition position) in /_/src/Compilers/Core/Portable/Text/TextLineCollection.cs:line 67
   at Microsoft.CodeAnalysis.LanguageServer.Handler.SemanticTokens.SemanticTokensHelpers.ComputeSemanticTokensDataAsync(Document document, ImmutableArray`1 spans, Boolean supportsVisualStudioExtensions, ClassificationOptions options, CancellationToken cancellationToken)
   at Microsoft.CodeAnalysis.LanguageServer.Handler.SemanticTokens.SemanticTokensHelpers.HandleRequestHelperAsync(Document document, ImmutableArray`1 spans, Boolean supportsVisualStudioExtensions, ClassificationOptions options, CancellationToken cancellationToken) in /_/src/LanguageServer/Protocol/Handler/SemanticTokens/SemanticTokensHelpers.cs:line 71
   at Microsoft.CodeAnalysis.LanguageServer.Handler.SemanticTokens.SemanticTokensHelpers.HandleRequestHelperAsync(IGlobalOptionService globalOptions, SemanticTokensRefreshQueue semanticTokensRefreshQueue, Range[] ranges, RequestContext context, CancellationToken cancellationToken) in /_/src/LanguageServer/Protocol/Handler/SemanticTokens/SemanticTokensHelpers.cs:line 49
   at Microsoft.CodeAnalysis.LanguageServer.Handler.SemanticTokens.SemanticTokensRangeHandler.HandleRequestAsync(SemanticTokensRangeParams request, RequestContext context, CancellationToken cancellationToken) in /_/src/LanguageServer/Protocol/Handler/SemanticTokens/SemanticTokensRangeHandler.cs:line 37
   at Microsoft.CommonLanguageServerProtocol.Framework.QueueItem`1.StartRequestAsync[TRequest,TResponse](TRequest request, TRequestContext context, IMethodHandler handler, String language, CancellationToken cancellationToken)
2026-05-25 14:32:27.980 [info] [Error - 2:32:27 PM] Request textDocument/semanticTokens/range failed.
2026-05-25 14:32:27.980 [info]   Message: The requested line number 104 must be less than the number of lines 100. (Parameter 'Line')
  Code: -32000 
[object Object]

Steps to Reproduce

It typically happens when i’m working with razor code which is not default html. For instance i have some classes called HoloPanel and if i do an error occurs

Operating System

Windows 10/11

Version Information

Version: 3.5.17 (user setup)
VSCode Version: 1.105.1
Commit: d5b2fc092e16007956c9e5047f76097b9e626ca0
Date: 2026-05-20T02:43:31.559Z
Layout: editor
Build Type: Stable
Release Track: Default
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Windows_NT x64 10.0.22631

Additional Information

Identifier
anysphere.csharp
Version
1.0.1
Last Updated
2025-12-06, 13:18:15

Does this stop you from using Cursor

No - Cursor works, but with this issue

5

Hey, thanks for the report and the stack trace.

This looks like a bug in the C# extension where the editor and the language server get out of sync on the document state. The server thinks there are 100 lines, but requests are coming in for line 104. Razor hits this more often because it mixes C# and HTML. I’ll pass this to the team.

A few quick questions so we have something solid to debug:

  • Can you reproduce it with a minimal .razor file that has a single custom component, or does it need a specific context? If you can share a repro, that’d be super helpful.
  • Does it happen more often after agent edits, or after manual editing?
  • Does Developer: Reload Window clear the issue until it happens again?

As a temporary workaround, you can disable inlay hints for C# by setting "editor.inlayHints.enabled": "off" to reduce the spam.

No ETA on a fix yet, but I’ll post an update in the thread once I have one.