Mixin every entity

[Quirin Schroll]

On Wednesday, 24 July 2024 at 11:57:35 UTC, Quirin Schroll wrote:
> Mixins can produce types, expressions, statements, and 
> declarations. That is great, but it could be better.
>
> Why not allow mixin identifiers, storage classes, attributes, 
> etc.?
>
> Contrived example:
> ```d
> struct mixin("C")
> {
> mixin("const"):
>     void f(mixin("ref") int x) mixin("@safe") { }
> }
> ```
>
> There’s no good reason a whole entity must be written in a 
> string literal with a “hole” to be filled by `format` just 
> because its name is generated. Interpolated strings help, but 
> are not fundamentally different.

One difference between usual mixins and mixins generating storage 
classes and attributes (possibly more entities) is that those 
would be valid when called with the empty string, resulting in no 
storage class or attribute.

---

The only place I’d exclude from having its name generated is a 
module.
```d
module mixin(expr);
```
That is a big no-no because module names are probably parsed 
specially. And that’s fine.