DIP proposal: Enum parameters

[Quirin Schroll]

On Saturday, 24 September 2022 at 07:51:32 UTC, Imperatorn wrote:
> I'm a bit torn about `static` vs `enum`. I partly agree with 
> prior speakers about `enum` getting too many meanings, but on 
> the other hand, it's not really a problem imo.

One biggie against using `static` is that on member functions it 
would have to go to the back (where it is currently invalid) with 
a totally different meaning than in front (although it would make 
the function a static).

Non-member:
```d
void f()(static int ctValue) { } // this is fine
```

Member:
```d
struct S
{
     void f()() static { } // different from:
     static void g()() { }

     void p()() enum { } // same as
     enum void q()() { }
}
```
This would be no problem if D did not allow putting some stuff 
before and after the function declaration with the same meaning. 
I really dislike `void f()() static { }`.

Currently, `enum` is valid for member functions like `q`, but 
does nothing. That would change, but I’d bet that almost no one 
has this in their code base anyway, so breakage would be minimal.