DIP1000: Walter's proposal to resolve ambiguity of ref-return-scope parameters

[Paul Backus]

On Friday, 26 November 2021 at 00:31:19 UTC, Dennis wrote:
> On Friday, 26 November 2021 at 00:26:35 UTC, Paul Backus wrote:
>> More seriously: this is exactly the kind of obscure "gotcha" 
>> that makes C++ so beginner-hostile, and IMO it is worth going 
>> to considerable lengths (including breaking changes) to avoid 
>> it.
>
> Allowing breaking changes, what syntax do you think makes 
> intuitive sense?

* Allow `return ref` and `return scope`.
* Forbid the `return` storage class from appearing in any other 
context.

This means breaking code that uses syntax like `ref return int a` 
and `return const ref int b`, which is unambiguous and currently 
allowed.

The benefit of this approach is that it establishes an exact, 
one-to-one correspondence between syntax and semantics. Rather 
than having to apply a bunch of context-dependent rules to work 
out which attributes go where, you can just look at the code and 
see.