Skip single use lifetime lint for generated opaque types
Fix: #77175
The opaque type generated by the desugaring process of an async function uses the lifetimes defined by the originating function. The DefId for the lifetimes in the opaque type are different from the ones in the originating async function - as they should be, as far as I understand, and could therefore be considered a single use lifetimes, this causes the single_use_lifetimes lint to fail compilation if explicitly denied. This fix skips the lint for lifetimes used only once in generated opaque types for an async function that are declared in the parent async function definition.
More info in the comments on the original issue: 1 and 2
Use smaller spans for some structured suggestions
Use more accurate suggestion spans for
* argument parse error
* fully qualified path
* missing code block type
* numeric casts
As reported in issue #77175, the opaque type generated by the desugaring process of an async function uses the lifetimes defined by the originating function. The definition ID for the lifetimes in the opaque method is different from the one in the originating async function and it could therefore be considered a single use of the lifetimne, this causes the single_use_lifetimes lint to fail compilation if explicitly denied. This fix skips the lint for lifetimes used only once in generated opaque types for an async function that are declared in the parent async function definition.
Remove `Session.if_let_suggestions`
We can instead if either the LHS or RHS types contain
`TyKind::Error`. In addition to covering the case where
we would have previously updated `if_let_suggestions`, this might
also prevent redundant errors in other cases as well.
We can instead if either the LHS or RHS types contain
`TyKind::Error`. In addition to covering the case where
we would have previously updated `if_let_suggestions`, this might
also prevent redundant errors in other cases as well.
Remove `Session.used_attrs` and move logic to `CheckAttrVisitor`
Instead of updating global state to mark attributes as used,
we now explicitly emit a warning when an attribute is used in
an unsupported position. As a side effect, we are to emit more
detailed warning messages (instead of just a generic "unused" message).
`Session.check_name` is removed, since its only purpose was to mark
the attribute as used. All of the callers are modified to use
`Attribute.has_name`
Additionally, `AttributeType::AssumedUsed` is removed - an 'assumed
used' attribute is implemented by simply not performing any checks
in `CheckAttrVisitor` for a particular attribute.
We no longer emit unused attribute warnings for the `#[rustc_dummy]`
attribute - it's an internal attribute used for tests, so it doesn't
mark sense to treat it as 'unused'.
With this commit, a large source of global untracked state is removed.
Instead of updating global state to mark attributes as used,
we now explicitly emit a warning when an attribute is used in
an unsupported position. As a side effect, we are to emit more
detailed warning messages (instead of just a generic "unused" message).
`Session.check_name` is removed, since its only purpose was to mark
the attribute as used. All of the callers are modified to use
`Attribute.has_name`
Additionally, `AttributeType::AssumedUsed` is removed - an 'assumed
used' attribute is implemented by simply not performing any checks
in `CheckAttrVisitor` for a particular attribute.
We no longer emit unused attribute warnings for the `#[rustc_dummy]`
attribute - it's an internal attribute used for tests, so it doesn't
mark sense to treat it as 'unused'.
With this commit, a large source of global untracked state is removed.
Suggest adding a type parameter for impls
Add a new suggestion upon encountering an unknown type in a `impl` that suggests adding a new type parameter. This diagnostic suggests to add a new type parameter even though it may be a const parameter, however after adding the parameter and running rustc again a follow up error steers the user to change the type parameter to a const parameter.
```rust
struct X<const C: ()>();
impl X<C> {}
```
suggests
```
error[E0412]: cannot find type `C` in this scope
--> bar.rs:2:8
|
1 | struct X<const C: ()>();
| ------------------------ similarly named struct `X` defined here
2 | impl X<C> {}
| ^
|
help: a struct with a similar name exists
|
2 | impl X<X> {}
| ^
help: you might be missing a type parameter
|
2 | impl<C> X<C> {}
| ^^^
```
After adding a type parameter the code now becomes
```rust
struct X<const C: ()>();
impl<C> X<C> {}
```
and the error now fully steers the user towards the correct code
```
error[E0747]: type provided when a constant was expected
--> bar.rs:2:11
|
2 | impl<C> X<C> {}
| ^
|
help: consider changing this type parameter to be a `const` generic
|
2 | impl<const C: ()> X<C> {}
| ^^^^^^^^^^^
```
r? `@estebank`
Somewhat related #84946
Handle more span edge cases in generics diagnostics
This should fix invalid suggestions that didn't account for empty bracket pairs (`<>`) or type bindings.
Fix `--remap-path-prefix` not correctly remapping `rust-src` component paths and unify handling of path mapping with virtualized paths
This PR fixes#73167 ("Binaries end up containing path to the rust-src component despite `--remap-path-prefix`") by preventing real local filesystem paths from reaching compilation output if the path is supposed to be remapped.
`RealFileName::Named` introduced in #72767 is now renamed as `LocalPath`, because this variant wraps a (most likely) valid local filesystem path.
`RealFileName::Devirtualized` is renamed as `Remapped` to be used for remapped path from a real path via `--remap-path-prefix` argument, as well as real path inferred from a virtualized (during compiler bootstrapping) `/rustc/...` path. The `local_path` field is now an `Option<PathBuf>`, as it will be set to `None` before serialisation, so it never reaches any build output. Attempting to serialise a non-`None` `local_path` will cause an assertion faliure.
When a path is remapped, a `RealFileName::Remapped` variant is created. The original path is preserved in `local_path` field and the remapped path is saved in `virtual_name` field. Previously, the `local_path` is directly modified which goes against its purpose of "suitable for reading from the file system on the local host".
`rustc_span::SourceFile`'s fields `unmapped_path` (introduced by #44940) and `name_was_remapped` (introduced by #41508 when `--remap-path-prefix` feature originally added) are removed, as these two pieces of information can be inferred from the `name` field: if it's anything other than a `FileName::Real(_)`, or if it is a `FileName::Real(RealFileName::LocalPath(_))`, then clearly `name_was_remapped` would've been false and `unmapped_path` would've been `None`. If it is a `FileName::Real(RealFileName::Remapped{local_path, virtual_name})`, then `name_was_remapped` would've been true and `unmapped_path` would've been `Some(local_path)`.
cc `@eddyb` who implemented `/rustc/...` path devirtualisation
