On borrow return type, suggest borrowing from arg or owned return type
When we encounter a function with a return type that has an anonymous lifetime with no argument to borrow from, besides suggesting the `'static` lifetime we now also suggest changing the arguments to be borrows or changing the return type to be an owned type.
```
error[E0106]: missing lifetime specifier
--> $DIR/variadic-ffi-6.rs:7:6
|
LL | ) -> &usize {
| ^ expected named lifetime parameter
|
= help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from
help: consider using the `'static` lifetime, but this is uncommon unless you're returning a borrowed value from a `const` or a `static`
|
LL | ) -> &'static usize {
| +++++++
help: instead, you are more likely to want to change one of the arguments to be borrowed...
|
LL | x: &usize,
| +
help: ...or alternatively, to want to return an owned value
|
LL - ) -> &usize {
LL + ) -> usize {
|
```
Fix #85843.
|
||
|---|---|---|
| .. | ||
| dyn-trait-underscore-in-struct.rs | ||
| dyn-trait-underscore-in-struct.stderr | ||
| dyn-trait-underscore.rs | ||
| dyn-trait-underscore.stderr | ||
| in-binder.rs | ||
| in-binder.stderr | ||
| in-fn-return-illegal.rs | ||
| in-fn-return-illegal.stderr | ||
| in-struct.rs | ||
| in-struct.stderr | ||
| underscore-lifetime-binders.rs | ||
| underscore-lifetime-binders.stderr | ||
| underscore-lifetime-elison-mismatch.rs | ||
| underscore-lifetime-elison-mismatch.stderr | ||
| underscore-outlives-bounds.rs | ||
| underscore-outlives-bounds.stderr | ||
| where-clause-inherent-impl-ampersand-rust2015.fixed | ||
| where-clause-inherent-impl-ampersand-rust2015.rs | ||
| where-clause-inherent-impl-ampersand-rust2015.stderr | ||
| where-clause-inherent-impl-ampersand-rust2018.fixed | ||
| where-clause-inherent-impl-ampersand-rust2018.rs | ||
| where-clause-inherent-impl-ampersand-rust2018.stderr | ||
| where-clause-inherent-impl-underscore.rs | ||
| where-clause-inherent-impl-underscore.rust2015.stderr | ||
| where-clause-inherent-impl-underscore.rust2018.stderr | ||
| where-clause-trait-impl-region-2015.fixed | ||
| where-clause-trait-impl-region-2015.rs | ||
| where-clause-trait-impl-region-2015.stderr | ||
| where-clause-trait-impl-region-2018.fixed | ||
| where-clause-trait-impl-region-2018.rs | ||
| where-clause-trait-impl-region-2018.stderr | ||
| where-clause-trait-impl-underscore.rs | ||
| where-clause-trait-impl-underscore.rust2015.stderr | ||
| where-clause-trait-impl-underscore.rust2018.stderr | ||
| where-clauses.rs | ||
| where-clauses.stderr | ||