1 error[E0309]: the parameter type `T` may not live long enough
2 --> $DIR/issue-84931.rs:14:21
4 LL | type Item<'a> = &'a mut T;
5 | ^^^^^^^^^- help: consider adding a where clause: `where T: 'a`
7 | ...so that the reference type `&'a mut T` does not outlive the data it points at
9 error: aborting due to previous error
11 For more information about this error, try `rustc --explain E0309`.