rust/compiler/rustc_infer
Esteban Küber 120049fab4 Always constrain the return type in lifetime suggestion
```
error: lifetime may not live long enough
 --> f205.rs:8:16
  |
7 |     fn resolve_symbolic_reference(&self, reference: Option<Reference>) -> Option<Reference> {
  |                                   -      --------- has type `Option<Reference<'1>>`
  |                                   |
  |                                   let's call the lifetime of this reference `'2`
8 |         return reference;
  |                ^^^^^^^^^ method was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
  |
help: consider introducing a named lifetime parameter
  |
7 |     fn resolve_symbolic_reference<'a>(&'a self, reference: Option<Reference<'a>>) -> Option<Reference<'a>> {
  |                                  ++++  ++                                  ++++                      ++++
```

The correct suggestion would be

```
help: consider introducing a named lifetime parameter
  |
7 |     fn resolve_symbolic_reference<'a>(&self, reference: Option<Reference<'a>>) -> Option<Reference<'a>> {
  |                                  ++++                                   ++++                      ++++
```

but we are not doing the analysis to detect that yet. If we constrain `&'a self`, then the return type with a borrow will implicitly take its lifetime from `'a`, it is better to make it explicit in the suggestion, in case that `&self` *doesn't* need to be `'a`, but the return does.
2024-05-17 20:31:13 +00:00
..
src Always constrain the return type in lifetime suggestion 2024-05-17 20:31:13 +00:00
Cargo.toml Convert TypeVisitor and DefIdVisitor to use VisitorResult 2024-03-05 13:28:15 -05:00
messages.ftl Use fn ptr signature instead of {closure@..} in infer error 2024-04-10 00:41:27 +00:00