MethodRef to overloaded generic method

[phdjonov]

I'm probably just missing the obvious, but I can't figure out how to emit a call to a specific overload of a generic method.

For instance, given something like the following:

static class C
{
    static ref T M<T>(T[] a, int b); // #1
    static ref T M<T>(T[] a, uint b); // #2
    static ref T M<T>(T[] a, IntPtr b); / /#3
    static ref T M<T>(T[] a, UIntPtr b); // #4
}

How would I emit a call to overload 4, instantiated for, say, string?

Emit.Call(new MethodRef(typeof(C), nameof(C.M)).MakeGenericMethod(typeof(string))); 
//error: ambiguous function, as expected

Emit.Call(new MethodRef(typeof(C), nameof(C.M), typeof(???), typeof(UIntPtr)).MakeGenericMethod(typeof(string))); 
//what goes in the ??? - string[] doesn't work (as expected)

I'm trying to avoid popping variables, calling through regular C# code, and then pushing the result as this generates unnecessary locals and instructions, and I seem to be right at the edge of what the JIT will optimize well and want to stay under that mark.

Thanks.

[ltrzesniewski]

Sorry, but that looks like something I forgot to implement. Oops 😰 I'll add support for this in the next version, but you'll need to wait a few weeks. Thanks for the report!

[phdjonov]

Hey thanks for the quick response!

No worries about the wait. I'm just looking forward to ripping out the ugly workaround whenever you publish the update.

Cheers!

[ltrzesniewski]

I'll release v1.2.0 with the fix today. Please tell me if it works for you as I've changed how things work with generics quite a bit.

You need to use the following code for your example case:

IL.Emit.Call(
    new MethodRef(
        typeof(C),
        nameof(C.M),
        TypeRef.MethodGenericParameters[0].MakeArrayType(),
        typeof(UIntPtr)
    ).MakeGenericMethod(typeof(string))
);

See #11 for details.

[phdjonov]

That's working perfectly. Thanks!