match_same_arms does not take lifetimes into account #8919
Description
Summary
Taken from this real-world example: https://github.com/rust-lang/log/blob/7fb28c36c7a418912612ab37ab49bd4ca1a3a7f5/src/lib.rs#L812-L826
Lint Name
match_same_arms
Reproducer
I tried this code:
#![warn(clippy::match_same_arms)] pub enum MaybeStaticStr<'a> { Static(&'static str), Borrowed(&'a str), } impl<'a> MaybeStaticStr<'a> { pub fn get(&self) -> &'a str { match *self { MaybeStaticStr::Static(s) => s, MaybeStaticStr::Borrowed(s) => s, } } }I saw this happen:
warning: this match arm has an identical body to another arm --> src/lib.rs:12:13 | 12 | MaybeStaticStr::Borrowed(s) => s, | ---------------------------^^^^^ | | | help: try merging the arm patterns: `MaybeStaticStr::Borrowed(s) | MaybeStaticStr::Static(s)` | note: the lint level is defined here --> src/lib.rs:1:9 | 1 | #![warn(clippy::match_same_arms)] | ^^^^^^^^^^^^^^^^^^^^^^^ = help: or try changing either arm body note: other arm here --> src/lib.rs:11:13 | 11 | MaybeStaticStr::Static(s) => s, | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#match_same_arms Problem is, that if I do that:
error[[E0495]](https://doc.rust-lang.org/stable/error-index.html#E0495): cannot infer an appropriate lifetime due to conflicting requirements --> src/lib.rs:10:15 | 10 | match *self { | ^^^^^ | note: first, the lifetime cannot outlive the lifetime `'a` as defined here... --> src/lib.rs:8:6 | 8 | impl<'a> MaybeStaticStr<'a> { | ^^ note: ...so that the types are compatible --> src/lib.rs:10:15 | 10 | match *self { | ^^^^^ = note: expected `MaybeStaticStr<'_>` found `MaybeStaticStr<'a>` = note: but, the lifetime must be valid for the static lifetime... note: ...so that the types are compatible --> src/lib.rs:12:38 | 12 | MaybeStaticStr::Borrowed(s) => s, | ^ = note: expected `&'static str` found `&str` Version
rustc 1.63.0-nightly (28b891916 2022-05-29) binary: rustc commit-hash: 28b891916d4c85cd10fb2e9cfa8bc836a2c459f3 commit-date: 2022-05-29 host: x86_64-unknown-linux-gnu release: 1.63.0-nightly LLVM version: 14.0.4 Additional Labels
@rustbot label +I-suggestion-causes-error