InterfaceMap returns non-GenericMethodDefinition for static abstract interface generic methods on the target type

[mburbea]

Description

InterfaceMap when mapping static abstract generic methods does not return a generic method definition. The generic arguments are also generic method type parameters, but they are the ones for the interface type.

Reproduction Steps

public interface I<T> where T : I<T>
{
    public void Instance<M>(M m);
    public static abstract void Static<M>(M m);
}

public readonly struct C : I<C>
{
    public void Instance<M>(M m) { }
    public static void Static<M>(M m) { }
}

internal class Program
{
    static void Main(string[] args)
    {
        var interfaceMap = typeof(C).GetInterfaceMap(typeof(I<C>));
        for (int i = 0; i < interfaceMap.InterfaceMethods.Length; i++)
        {
            var imethod = interfaceMap.InterfaceMethods[i];
            var tmethod = interfaceMap.TargetMethods[i];
            Console.WriteLine($"Interface.{imethod.Name} is generic method def: {imethod.IsGenericMethodDefinition}");
            Console.WriteLine($"Target.{tmethod.Name} is generic method def: {tmethod.IsGenericMethodDefinition}");
        }
        
        Console.Read();
    }
}

Expected behavior

Interface.Instance is generic method def: True
Target.Instance is generic method def: True
Interface.Static is generic method def: True
Target.Static is generic method def: True

Actual behavior

Interface.Instance is generic method def: True
Target.Instance is generic method def: True
Interface.Static is generic method def: True
Target.Static is generic method def: False

Regression?

No as these are new.

Known Workarounds

No response

Configuration

.net 7 preview 7.

Other information

No response

[MichalStrehovsky]

Cc @trylek @davidwrighton

[mangod9]

@trylek can you take a look at this issue if this is required for 8?

[jkotas]

We have number of issues in GetInterfaceMap for static interface methods. See #90518 and the issues that it is linked to.

[trylek]

I have verified locally that this bug no longer reproes as of .NET 8 RC1, I believe it was fixed earlier this year by David Wrighton.