rust/compiler/rustc_mir_build
bors 36ecbc94eb Auto merge of #80632 - Nadrieril:fix-80501, r=varkor
Identify unreachable subpatterns more reliably

In https://github.com/rust-lang/rust/pull/80104 I used `Span`s to identify unreachable sub-patterns in the presence of or-patterns during exhaustiveness checking. In https://github.com/rust-lang/rust/issues/80501 it was revealed that `Span`s are complicated and that this was not a good idea.
Instead, this PR identifies subpatterns logically: as a path in the tree of subpatterns of a given pattern. I made a struct that captures a set of such subpatterns. This is a bit complex, but thankfully self-contained; the rest of the code does not need to know anything about it.
Fixes https://github.com/rust-lang/rust/issues/80501. I think I managed to keep the perf neutral.

r? `@varkor`
2021-02-07 16:48:57 +00:00
..
src Auto merge of #80632 - Nadrieril:fix-80501, r=varkor 2021-02-07 16:48:57 +00:00
Cargo.toml