rust/compiler/rustc_trait_selection
Matthias Krüger 890c4d2e26
Rollup merge of #137245 - estebank:from-residual-note-2, r=oli-obk
Tweak E0277 when predicate comes indirectly from ?

When a `?` operation requires an `Into` conversion with additional bounds (like having a concrete error but wanting to convert to a trait object), we handle it speficically and provide the same kind of information we give other `?` related errors.

```
error[E0277]: `?` couldn't convert the error: `E: std::error::Error` is not satisfied
  --> $DIR/bad-question-mark-on-trait-object.rs:7:13
   |
LL | fn foo() -> Result<(), Box<dyn std::error::Error>> {
   |             -------------------------------------- required `E: std::error::Error` because of this
LL |     Ok(bar()?)
   |        -----^ the trait `std::error::Error` is not implemented for `E`
   |        |
   |        this has type `Result<_, E>`
   |
note: `E` needs to implement `std::error::Error`
  --> $DIR/bad-question-mark-on-trait-object.rs:1:1
   |
LL | struct E;
   | ^^^^^^^^
   = note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
   = note: required for `Box<dyn std::error::Error>` to implement `From<E>`
```

Avoid talking about `FromResidual` when other more relevant information is being given, particularly from `rust_on_unimplemented`.

Fix #137238.

-----

CC #137232, which was a smaller step related to this.
2025-02-22 01:01:41 +01:00
..
src Rollup merge of #137245 - estebank:from-residual-note-2, r=oli-obk 2025-02-22 01:01:41 +01:00
Cargo.toml Make fewer crates depend on rustc_ast_ir 2025-02-19 07:06:54 +00:00
messages.ftl Rework rustc_dump_vtable 2025-01-30 15:30:04 +00:00