IDE0049 should be updated to suggest converting IntPtr to nint and UIntPtr to nuint.

[buyaa-n]

Brief description:

As mentioned in dotnet/runtime#72348 with the numeric IntPtr feature, nint is now an alias for System.IntPtr and nuint is alias for System.UIntPtr, the analyzer IDE0049 should be updated to suggest converting IntPtr to nint and UIntPtr to nuint. Preferably default to "Info" level.

Languages applicable:

C# only

Additional information:

Related to dotnet/runtime#72348

Documentation requirements:

When this analyzer is updated, the Documentation for IDE0049 analyzers could be updated accordingly.

[Youssef1313]

Note: we have two analyzers, one that goes from C# aliases to .NET types and one that goes from .NET types to C# aliases.

Both should be updated.

https://github.com/dotnet/roslyn/blob/eaf6778d7238a206876917a24eb8dd9c6dfa3909/src/Features/CSharp/Portable/Diagnostics/Analyzers/CSharpPreferFrameworkTypeDiagnosticAnalyzer.cs

https://github.com/dotnet/roslyn/blob/eaf6778d7238a206876917a24eb8dd9c6dfa3909/src/Features/CSharp/Portable/Diagnostics/Analyzers/CSharpSimplifyTypeNamesDiagnosticAnalyzer.cs

[CyrusNajmabadi]

@cston can you point to docs (or give the rules) on precisely when we should consider these types equivalent?

[cston]

The compiler treats nint / nuint as aliases for System.IntPtr / System.UIntPtr when compiling with a corlib that includes System.Runtime.CompilerServices.RuntimeFeature.NumericIntPtr. Otherwise, the pairs of types are considered distinct.

[CyrusNajmabadi]

Sounds good. I see tehre is AssemblySYmbol.RuntimeSupportsNumericIntPtr. Could we expose that publicly?

[buyaa-n]

This also should consider @jkotas suggestion in the original issue:

It would be nice for the code-fixer to suggest replacing IntPtr with actual pointer types where the code is actually operating on pointers.

Blank replacing IntPtr with nint will often make code harder to understand. See discussion in dotnet/runtime#70297