mixin template's alias parameter ... ignored ?

[someone]

```d
mixin template templateUGC (
    typeStringUTF,
    alias lstrStructureID
    ) {

    public struct lstrStructureID {

       typeStringUTF whatever;

    }

}

mixin templateUGC!(string,  "gudtUGC08");
mixin templateUGC!(dstring, "gudtUGC16");
mixin templateUGC!(wstring, "gudtUGC32");

void main() {

    gudtUGC32 something; /// Error: undefined identifier 
`gudtUGC32`

}
```

I cannot manage to get this right; not even with:

```d
    public struct mixin(lstrStructureID) { ... }
```

because the argument seems to require a complete statement.