rust/compiler/rustc_hir_analysis
bors 94bc9c737e Auto merge of #114811 - estebank:impl-ambiguity, r=wesleywiser
Show more information when multiple `impl`s apply

- When there are `impl`s without type params, show only those (to avoid showing overly generic `impl`s).
```
error[E0283]: type annotations needed
  --> $DIR/multiple-impl-apply.rs:34:9
   |
LL |     let y = x.into();
   |         ^     ---- type must be known at this point
   |
note: multiple `impl`s satisfying `_: From<Baz>` found
  --> $DIR/multiple-impl-apply.rs:14:1
   |
LL | impl From<Baz> for Bar {
   | ^^^^^^^^^^^^^^^^^^^^^^
...
LL | impl From<Baz> for Foo {
   | ^^^^^^^^^^^^^^^^^^^^^^
   = note: required for `Baz` to implement `Into<_>`
help: consider giving `y` an explicit type
   |
LL |     let y: /* Type */ = x.into();
   |          ++++++++++++
```

- Lower the importance of `T: Sized`, `T: WellFormed` and coercion errors, to prioritize more relevant errors. The pre-existing deduplication logic deals with hiding redundant errors better that way, and we show errors with more metadata that is useful to the user.

- Show `<SelfTy as Trait>::assoc_fn` suggestion in more cases.
```
error[E0790]: cannot call associated function on trait without specifying the corresponding `impl` type
  --> $DIR/cross-return-site-inference.rs:38:16
   |
LL |     return Err(From::from("foo"));
   |                ^^^^^^^^^^ cannot call associated function of trait
   |
help: use a fully-qualified path to a specific available implementation
   |
LL |     return Err(</* self type */ as From>::from("foo"));
   |                +++++++++++++++++++     +
```

Fix #88284.
2023-10-06 18:44:32 +00:00
..
src Auto merge of #114811 - estebank:impl-ambiguity, r=wesleywiser 2023-10-06 18:44:32 +00:00
Cargo.toml drop unused deps, gate libc under unix for one crate 2023-04-22 15:22:21 +03:00
README.md rustc_typeck to rustc_hir_analysis 2022-09-27 10:37:23 +02:00
messages.ftl Rollup merge of #115863 - chenyukang:yukang-add-message-tidy-check, r=davidtwco 2023-10-03 12:24:11 +02:00

README.md

For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.