Show trait method signature when impl differs
When the trait's span is available, it is already being used, add a
`note` for the cases where the span isn't available:
<pre>
error[E0053]: <b>method `fmt` has an incompatible type for trait</b>
--> $DIR/trait_type.rs:17:4
|
17 | fn fmt(&self, x: &str) -> () { }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ types differ in mutability
|
= note: expected type `<b>fn(&MyType, &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error></b>`
found type `<b>fn(&MyType, &str)</b>`
error[E0050]: <b>method `fmt` has 1 parameter but the declaration in trait `std::fmt::Display::fmt` has 2</b>
--> $DIR/trait_type.rs:21:11
|
21 | fn fmt(&self) -> () { }
| ^^^^^ expected 2 parameters, found 1
|
= note: `fmt` from trait: `<b>fn(&Self, &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error></b>`
error[E0186]: <b>method `fmt` has a `&self` declaration in the trait, but not in the impl</b>
--> $DIR/trait_type.rs:25:4
|
25 | fn fmt() -> () { }
| ^^^^^^^^^^^^^^^^^^ expected `&self` in impl
|
= note: `fmt` from trait: `<b>fn(&Self, &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error></b>`
error[E0046]: <b>not all trait items implemented, missing: `fmt`</b>
--> $DIR/trait_type.rs:28:1
|
28 | impl std::fmt::Display for MyType4 {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `fmt` in implementation
|
= note: `fmt` from trait: `<b>fn(&Self, &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error></b>`
</code></pre>
Fix#28011.
0418fa9d38