first draft Reducing the legal permutations of ref-return-scope

[Dennis]

On Tuesday, 13 May 2025 at 04:23:05 UTC, Walter Bright wrote:
> https://github.com/WalterBright/documents/blob/master/ReturnRefScope.md

I like the idea.

> The trouble is it's forgettable which order means what

 From what I've heard, what's most confusing is that order matters 
at all. Usually attributes are order independent: there's no 
difference between `const private @safe` and `private @safe 
const`. So `scope return` being subtly different than `return 
scope` is very surprising.

> scope return was given special meaning

*`return scope` was given special meaning

> For a parameter to be returning a ref, return ref will be 
> required

What about the implicit `ref this` parameter?

```D
struct S
{
     int* f() return; // doesn't comply with DIP text
     int* g() return ref; // syntax error currently
}
```

Also what about variations on `return scope`?
```D
int* f(return scope int* p); // recommended
int* g(return int* p);       // currently allowed
int* h(scope return int* p); // currently allowed
```