Wrong types in create-temporary rewrites (CommaExp) wrt. `alias this`

[TurkeyMan]

It is alleged that this is a frontend issue that breaks LDC: https://github.com/ldc-developers/ldc/issues/4882

[kinke]

Test case from https://github.com/ldc-developers/ldc/issues/4246#issuecomment-1308175222:

struct Result(Type) {
    Type get() {  assert(0); }

    alias get this;

    this(ref Result) {}
}

float dotProduct() {
    Result!float got;
    return got;
}

The got in return got; is rewritten to: (float __copytmp2 = got.get(); __copytmp2). The type of the overall CommaExp is Result!float (instead of float), and so is the 2nd nested expression's (__copytmp2).

Additionally, the temporary isn't required - it's a trivial float. Result!float is no POD because of the copy ctor, I guess that tricks the frontend into thinking it has to create a float temporary (because it's using the wrong Result!float type, not float).

[TurkeyMan]

This is constantly creating ICE in LDC; someone needs to fix this...

[TurkeyMan]

So, is this fixed now? Does DMD need to take any action? I thought it was said the problem was a DMD bug, but it seems they fixed it in LDC?

[kinke]

Just because the DMD codegenerator doesn't hick up on the wrong AST types doesn't mean this is an LDC issue.