spurious "shadowed label name" warning

[durka]

This playpen has an outer loop called 'outer with two inner loops, one after the other, both called 'inner. The warning says the name 'inner is shadowed, but it seems like it really isn't, since you can't refer to a loop's label after the end of the loop.

[frewsxcv]

Minimal example:

fn main() {
    'outer: while false {}
    'outer: while false {}
}

<anon>:3:13: 3:27 warning: label name `'outer` shadows a label name that is already in scope
<anon>:3     'outer: while false {}
                     ^~~~~~~~~~~~~~
<anon>:2:13: 2:27 note: shadowed label `'outer` declared here
<anon>:2     'outer: while false {}
                     ^~~~~~~~~~~~~~

Playpen link for the code above

[ghost]

This seems like intended behaviour, see #24162.

[durka]

Ah, future proofing! Makes sense, thanks.