rust/compiler
bors e60e19bc65 Auto merge of #90179 - Nilstrieb:lifetime-elision-mismatch-hint, r=estebank
Add beginner friendly lifetime elision hint to E0623

Address #90170

Suggest adding a new lifetime parameter when two elided lifetimes should match up but don't.

Example:

```
error[E0623]: lifetime mismatch
  --> $DIR/issue-90170-elision-mismatch.rs:2:35
   |
LL | fn foo(slice_a: &mut [u8], slice_b: &mut [u8]) {
   |                 ---------           --------- these two types are declared with different lifetimes...
LL |     core::mem::swap(&mut slice_a, &mut slice_b);
   |                                   ^^^^^^^^^^^^ ...but data from `slice_b` flows into `slice_a` here
   |
   = note: each elided lifetime in input position becomes a distinct lifetime
help: explicitly declare a lifetime and assign it to both
   |
LL | fn foo<'a>(slice_a: &'a mut [u8], slice_b: &'a mut [u8]) {
   |       ++++           ++                     ++

```

for

```rust
fn foo(slice_a: &mut [u8], slice_b: &mut [u8]) {
    core::mem::swap(&mut slice_a, &mut slice_b);
}
```
2021-11-04 00:39:21 +00:00
..
2021-10-16 13:36:05 -07:00
2021-10-23 21:55:57 -04:00
2021-10-29 11:15:45 -04:00
2021-11-01 10:39:43 +01:00
2021-11-03 16:43:12 +01:00