Move name resolution logic to a dedicated file
The code resolution logic from an Ident is scattered between several files.
The first commits creates `rustc_resolve::probe` module to hold the different mutually recursive functions together. Just a move, no code change.
The following commits attempt to make the logic a bit more readable.
The two fields `last_import_segment` and `unusable_binding` are replaced by function parameters.
In order to manage the fallout, `maybe_` variants of the function are added, dedicated to speculative resolution.
r? `@petrochenkov`
This commit updates the signatures of all diagnostic functions to accept
types that can be converted into a `DiagnosticMessage`. This enables
existing diagnostic calls to continue to work as before and Fluent
identifiers to be provided. The `SessionDiagnostic` derive just
generates normal diagnostic calls, so these APIs had to be modified to
accept Fluent identifiers.
In addition, loading of the "fallback" Fluent bundle, which contains the
built-in English messages, has been implemented.
Each diagnostic now has "arguments" which correspond to variables in the
Fluent messages (necessary to render a Fluent message) but no API for
adding arguments has been added yet. Therefore, diagnostics (that do not
require interpolation) can be converted to use Fluent identifiers and
will be output as before.
`MultiSpan` contains labels, which are more complicated with the
introduction of diagnostic translation and will use types from
`rustc_errors` - however, `rustc_errors` depends on `rustc_span` so
`rustc_span` cannot use types like `DiagnosticMessage` without
dependency cycles. Introduce a new `rustc_error_messages` crate that can
contain `DiagnosticMessage` and `MultiSpan`.
Signed-off-by: David Wood <david.wood@huawei.com>
Also remove a redundant parameter from `fn resolve_path(_with_ribs)`, `crate_lint: CrateLint` is a more detailed version of `record_used: bool` with `CrateLint::No` meaning `false` and anything else meaning `true`.
By changing `as_str()` to take `&self` instead of `self`, we can just
return `&str`. We're still lying about lifetimes, but it's a smaller lie
than before, where `SymbolStr` contained a (fake) `&'static str`!
This also fixes the same suggestion, which was kind of broken, because it just searched for the last occurence of `const` to replace with a `let`. This works great in some cases, but when there is no const and a leading space to the file, it doesn't work and panic with overflow because it thought that it had found a const.
I also changed the suggestion to only trigger if the `const` and the non-constant value are on the same line, because if they aren't, the suggestion is very likely to be wrong.
Also don't trigger the suggestion if the found `const` is on line 0, because that triggers the ICE.
Improve and test cross-crate hygiene
- Decode the parent expansion for traits and enums in `rustc_resolve`, this was already being used for resolution in typeck
- Avoid suggesting importing names with def-site hygiene, since it's often not useful
- Add more tests
r? `@petrochenkov`
Emit description of the ambiguity as a note.
Co-authored-by: Noah Lev <camelidcamel@gmail.com>
Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Adopt let_else across the compiler
This performs a substitution of code following the pattern:
```
let <id> = if let <pat> = ... { identity } else { ... : ! };
```
To simplify it to:
```
let <pat> = ... { identity } else { ... : ! };
```
By adopting the `let_else` feature (cc #87335).
The PR also updates the syn crate because the currently used version of the crate doesn't support `let_else` syntax yet.
Note: Generally I'm the person who *removes* usages of unstable features from the compiler, not adds more usages of them, but in this instance I think it hopefully helps the feature get stabilized sooner and in a better state. I have written a [comment](https://github.com/rust-lang/rust/issues/87335#issuecomment-944846205) on the tracking issue about my experience and what I feel could be improved before stabilization of `let_else`.
This performs a substitution of code following the pattern:
let <id> = if let <pat> = ... { identity } else { ... : ! };
To simplify it to:
let <pat> = ... { identity } else { ... : ! };
By adopting the let_else feature.
avoid suggesting the same name
sort candidates
fix a message
use `opt_def_id` instead of `def_id`
move `find_similarly_named_module_or_crate` to rustc_resolve/src/diagnostics.rs
Do not suggest importing inaccessible items
Fixes#88472. For this example:
```rust
mod a {
struct Foo;
}
mod b {
type Bar = Foo;
}
```
rustc currently emits:
```
error[E0412]: cannot find type `Foo` in this scope
--> test.rs:6:16
|
6 | type Bar = Foo;
| ^^^ not found in this scope
|
help: consider importing this struct
|
6 | use a::Foo;
|
```
this is incorrect, as applying this suggestion leads to
```
error[E0603]: struct `Foo` is private
--> test.rs:6:12
|
6 | use a::Foo;
| ^^^ private struct
|
note: the struct `Foo` is defined here
--> test.rs:2:5
|
2 | struct Foo;
| ^^^^^^^^^^^
```
With my changes, I get:
```
error[E0412]: cannot find type `Foo` in this scope
--> test.rs:6:16
|
6 | type Bar = Foo;
| ^^^ not found in this scope
|
= note: this struct exists but is inaccessible:
a::Foo
```
As for the wildcard mentioned in #88472, I would argue that the warning is actually correct, since the import _is_ unused. I think the real issue is the wrong suggestion, which I have fixed here.
Suggest similarly named associated items in trait impls
Fix#85942
Previously, the compiler didn't suggest similarly named associated items unlike we do in many situations. This patch adds such diagnostics for associated functions, types, and constants.
Previously, the compiler didn't suggest similarly named associated items
unlike we do in many situations. This patch adds such diagnostics for
associated functions, types and constants.
