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