I don’t mind this idea.
However, in today’s Rust, _
is permitted in two different contexts with two different meanings:
- In type contexts it means “please infer the type”.
- In patterns
_
means “I don’t care / match anything”.
If we permit const _
, then that makes for another 3rd context, which is quite ad-hoc.
If instead we could bring const
closer to let
bindings, then we could support const $pat
and things such as:
const (FOO, BAR): (usize, usize) = (1, 2);
In that case, const _
falls out naturally because _
is a pattern.