rust/tests/ui/match/match-ref-mut-invariance.stderr
2023-01-11 09:32:08 +00:00

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error: lifetime may not live long enough
--> $DIR/match-ref-mut-invariance.rs:10:9
|
LL | impl<'b> S<'b> {
| -- lifetime `'b` defined here
LL | fn bar<'a>(&'a mut self) -> &'a mut &'a i32 {
| -- lifetime `'a` defined here
LL | match self.0 { ref mut x => x }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ associated function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a`
|
= help: consider adding the following bound: `'a: 'b`
= note: requirement occurs because of a mutable reference to `&i32`
= note: mutable references are invariant over their type parameter
= help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
error: aborting due to previous error