bors 1f5bc176b0 Auto merge of #80104 - Nadrieril:usefulness-merging, r=varkor ... Improve and fix diagnostics of exhaustiveness checking Primarily, this fixes https://github.com/rust-lang/rust/issues/56379. This also fixes incorrect interactions between or-patterns and slice patterns that I discovered while working on #56379. Those two examples show the incorrect diagnostics: ```rust match &[][..] { [true] => {} [true // detected as unreachable but that's not true | false, ..] => {} _ => {} } match (true, None) { (true, Some(_)) => {} (false, Some(true)) => {} (true | false, None | Some(true // should be detected as unreachable | false)) => {} } ``` I did not measure any perf impact. However, I suspect that [`616ba9f`](https://github.com/rust-lang/rust/pull/80104/commits/616ba9f9f7f5845777a36e1a41a515e6c33a8776) should have a negative impact on large or-patterns. I'll see what the perf run says; I have optimization ideas up my sleeve if needed. EDIT: I initially had a noticeable perf impact that I thought unavoidable. I then proceeded to avoid it x) r? `@varkor` `@rustbot` label +A-exhaustiveness-checking		2020-12-19 19:14:04 +00:00
..
src	Auto merge of #80104 - Nadrieril:usefulness-merging, r=varkor	2020-12-19 19:14:04 +00:00
Cargo.toml	mv compiler to compiler/	2020-08-30 18:45:07 +03:00