C# Extension is Outdated

Support Bug Reports
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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

The C# extension does not support the .NET 10 features (i.e. C# 14 language features)

https://learn.microsoft.com/en-us/dotnet/core/whats-new/dotnet-10/overview#c-14

The other C# packages that are trying provide C# support are also using old versions of omnisharp and have noted this:

https://github.com/muhammadsammy/free-vscode-csharp/issues/98
https://github.com/muhammadsammy/free-vscode-csharp/issues/95

We are forced to either skip using modern C# features, or give up the debugging provided by anysphere.csharp to use a different extension.

Steps to Reproduce

  1. Create a new C# file
  2. Add a new language feature, for instance extension blocks, field backed properies, and null-conditional assigments:
public static class MyExtensions
{
    class TheThing
    {
        public string? Name
        {
            get;
            set => field = value?.ToLower() ?? "";
        }
    }

    extension(IServiceCollection services)
    {
        public IServiceCollection AddSomething()
        {
            TheThing? it = null;

            it?.Name = "Hello";

            return services;
        }
    }
}

Expected Behavior

No errors should be reported. This is perfectly correct C# 14 code.

I’ve included the same file open in VSCode, where there are no error squiggles and the code works correctly.

Screenshots / Screen Recordings

csharp-14-features-not-working.png
csharp-14-features-not-working.png1562×1051 97 KB

Operating System

Windows 10/11
MacOS
Linux

Version Information

Version: 3.2.16 (user setup)
VSCode Version: 1.105.1
Commit: 3e548838cf824b70851dd3ef27d0c6aae371b3f0
Date: 2026-04-28T21:07:47.682Z
Layout: editor
Build Type: Stable
Release Track: Early Access
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 10.0.26200

Does this stop you from using Cursor

Yes - Cursor is unusable

7

Hi @hlsrdevzeebo,

This is a known issue. Cursor’s bundled C# extension uses a version that doesn’t yet support C# 14, so features like extension blocks, field-backed properties, and null-conditional assignments get flagged as errors even though they compile fine.

Our team is tracking this. In the meantime, some community members have been using DotRush as an alternative C# language server, though you’d lose the integrated debugging.

Related thread with more context: Support for .NET 10 and C# 14 in Cursor AI IDE

8

That issue has been open for 4 months with zero updates. Is Cursor going to continuously be 4+ months behind on .NET features as they roll out in the future? C# 15 is coming out with .NET 11 in November. Are we going to not be able to use those features either?

10

Use DotRush the official one is usseless - its really good and I haven’t had to open Visual Studio for a long time. Not sure about C# though