[Issue 19303] hasMember fails to recognize member (interaction with mixin template)

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=19303

Eduard Staniloiu <edi33416 at gmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |edi33416 at gmail.com

--- Comment #1 from Eduard Staniloiu <edi33416 at gmail.com> ---
This is most definitely a compiler bug which seems to be related/triggered my
the template mixin, as `std.traits.hasMember` only calls the equivalent
`__traits(hasMember, T, memberName)` compiler trait.

As a workaround, you can use
static assert(__traits(hasMember, P, "ElementType")); // passes


Also, weirdly enough, swapping the mixin instantiation with the `static if`
block in `Port`, will pass the initial assert

```
struct Port(SomeSignal)
{
    static if(hasMember!(SomeSignal, "ElementType"))
        alias ElementType = SomeSignal.ElementType;

    mixin SignalOps;
}

void main()
{
    ...
    static assert(hasMember!(P, "ElementType")); // OK
    static assert(__traits(hasMember, P, "ElementType")); // OK
}
```

You can check this on https://run.dlang.io/is/6aXcGq

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