Suggest using deref in patterns
Fixes#132784
This changes the following code:
```rs
use std::sync::Arc;
fn main() {
let mut x = Arc::new(Some(1));
match x {
Some(_) => {}
None => {}
}
}
```
to output
```rs
error[E0308]: mismatched types
--> src/main.rs:5:9
|
LL | match x {
| - this expression has type `Arc<Option<{integer}>>`
...
LL | Some(_) => {}
| ^^^^^^^ expected `Arc<Option<{integer}>>`, found `Option<_>`
|
= note: expected struct `Arc<Option<{integer}>>`
found enum `Option<_>`
help: consider dereferencing to access the inner value using the Deref trait
|
LL | match *x {
| ~~
```
instead of
```rs
error[E0308]: mismatched types
--> src/main.rs:5:9
|
4 | match x {
| - this expression has type `Arc<Option<{integer}>>`
5 | Some(_) => {}
| ^^^^^^^ expected `Arc<Option<{integer}>>`, found `Option<_>`
|
= note: expected struct `Arc<Option<{integer}>>`
found enum `Option<_>`
```
This makes it more obvious that a Deref is available, and gives a suggestion on how to use it in order to fix the issue at hand.
db77788dc5