Suggest field typo through derefs
Take into account implicit dereferences when suggesting fields.
```
error[E0609]: no field `longname` on type `Arc<S>`
--> $DIR/suggest-field-through-deref.rs:10:15
|
LL | let _ = x.longname;
| ^^^^^^^^ help: a field with a similar name exists: `long_name`
```
CC https://github.com/rust-lang/rust/issues/78374#issuecomment-719564114
When encountering a type error caused by the use of `Self`, suggest
using the actual type name instead.
```
error[E0308]: mismatched types
--> $DIR/struct-path-self-type-mismatch.rs:13:9
|
LL | impl<T> Foo<T> {
| - ------ this is the type of the `Self` literal
| |
| found type parameter
LL | fn new<U>(u: U) -> Foo<U> {
| - ------ expected `Foo<U>` because of return type
| |
| expected type parameter
LL | / Self {
LL | |
LL | | inner: u
LL | |
LL | | }
| |_________^ expected `Foo<U>`, found `Foo<T>`
|
= note: expected struct `Foo<U>`
found struct `Foo<T>`
= note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
= note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
help: use the type name directly
|
LL | Foo::<U> {
| ~~~~~~~~
```
Fix#76086.
Suggest publicly accessible paths for items in private mod:
When encountering a path in non-import situations that are not reachable
due to privacy constraints, search for any public re-exports that the
user could use instead.
Track whether an import suggestion is offering a re-export.
When encountering a path with private segments, mention if the item at
the final path segment is not publicly accessible at all.
Add item visibility metadata to privacy errors from imports:
On unreachable imports, record the item that was being imported in order
to suggest publicly available re-exports or to be explicit that the item
is not available publicly from any path.
In order to allow this, we add a mode to `resolve_path` that will not
add new privacy errors, nor return early if it encounters one. This way
we can get the `Res` corresponding to the final item in the import,
which is used in the privacy error machinery.
Consider `tests/ui/const-generics/generic_const_exprs/issue-102768.stderr`,
the error message where it gives additional notes about where the associated
type is defined, and how the dead code lint doesn't have an article,
like in `tests/ui/lint/dead-code/issue-85255.stderr`. They don't have
articles, so it seems unnecessary to have one here.
