RS0042 incorrectly firing for ref usage

[jaredpar]

Consider the following code in roslyn

        public static ref TemporaryArray<T> AsRef<T>(this in TemporaryArray<T> array)
            => ref Unsafe.AsRef(in array);

This code is not copying a TemporaryArray<T> but just downgrading a in to a ref. This is firing RS0042 which seems incorrect though because there is no copy of the value here, just a change of the ref kind.

[sharwell]

That helper method exists for the sole purpose of avoiding diagnostics. Can you provide a more complete example showing how the error was observed?

[jaredpar]

The error was fired for that exact method. The ref Unsafe.AsRef(in array) is where it fires. You can see in this PR where I had to suppress RS0042 at this location

https://github.com/dotnet/roslyn/pull/71507/files#diff-0e7827689d069ca296c5c6ccf49bbf565e5eb4e6700b3ddd7769916a7b81b1e3

[sharwell]

Weird. So far I have not been able to reproduce this.

[sharwell]

Looks like dotnet/runtime#89736 changed the signature of Unsafe.AsRef to a form that isn't supported by the analyzer. Should be an easy fix.

[jaredpar]

That explains the timing of why I just started getting the analyzer failure.