Check uniqueness of impl items by trait item when applicable.
When checking uniqueness of item names in impl blocks, we currently use the same definition of hygiene as for toplevel items. This means that a plain item and one generated by a macro 2.0 do not collide.
This hygiene rule does not match with how impl items resolve to associated trait items. As a consequence, we misdiagnose the trait impls.
This PR proposes to consider that trait impl items are uses of the corresponding trait items during resolution, instead of checking for duplicates later. An error is emitted when a trait impl item is used twice.
There should be no stable breakage, since macros 2.0 are still unstable.
r? ``@petrochenkov``
cc ``@RalfJung``
Fixes https://github.com/rust-lang/rust/issues/71614.
Move lifetime resolution module to rustc_hir_analysis.
Now that lifetime resolution has been removed from it, this file has nothing to do in `rustc_resolve`. It's purpose is to compute Debruijn indices for lifetimes, so let's put it in type collection.
suggest candidates for unresolved import
Currently we prompt suggestion of candidates(help notes of `use xxx::yyy`) for names which cannot be resolved, but we don't do that for import statements themselves that couldn't be resolved. It seems reasonable to add candidate help information for these statements as well.
Fixes#102711
Uplift `clippy::for_loops_over_fallibles` lint into rustc
This PR, as the title suggests, uplifts [`clippy::for_loops_over_fallibles`] lint into rustc. This lint warns for code like this:
```rust
for _ in Some(1) {}
for _ in Ok::<_, ()>(1) {}
```
i.e. directly iterating over `Option` and `Result` using `for` loop.
There are a number of suggestions that this PR adds (on top of what clippy suggested):
1. If the argument (? is there a better name for that expression) of a `for` loop is a `.next()` call, then we can suggest removing it (or rather replacing with `.by_ref()` to allow iterator being used later)
```rust
for _ in iter.next() {}
// turns into
for _ in iter.by_ref() {}
```
2. (otherwise) We can suggest using `while let`, this is useful for non-iterator, iterator-like things like [async] channels
```rust
for _ in rx.recv() {}
// turns into
while let Some(_) = rx.recv() {}
```
3. If the argument type is `Result<impl IntoIterator, _>` and the body has a `Result<_, _>` type, we can suggest using `?`
```rust
for _ in f() {}
// turns into
for _ in f()? {}
```
4. To preserve the original behavior and clear intent, we can suggest using `if let`
```rust
for _ in f() {}
// turns into
if let Some(_) = f() {}
```
(P.S. `Some` and `Ok` are interchangeable depending on the type)
I still feel that the lint wording/look is somewhat off, so I'll be happy to hear suggestions (on how to improve suggestions :D)!
Resolves#99272
[`clippy::for_loops_over_fallibles`]: https://rust-lang.github.io/rust-clippy/master/index.html#for_loops_over_fallibles
Add missing documentation for FileNameDisplayPreference variants
Took me a while to find the information when I needed it so hopefully it should save some time for the next ones.
r? ``@thomcc``
Elaborate trait ref to compute object safety.
instead of building them manually from supertraits and associated items.
This allows to have the correct substs for GATs.
Fixes https://github.com/rust-lang/rust/issues/102751
rename `ImplItemKind::TyAlias` to `ImplItemKind::Type`
The naming of this variant seems inconsistent given that this is not really a "type alias", and the associated type variant for `TraitItemKind` is just called `Type`.
Show let-else suggestion on stable.
The E0005 error message has a suggestion to use let-else. Now that let-else is stabilized, I think this message should be included on non-nightly toolchains. I suspect this was just an oversight from #93628. [`E0005.stderr`](be1c7aad72/src/test/ui/error-codes/E0005.stderr (L22-L25)) contains an example of what this suggestion looks like.
I refactored the code:
- Removed handling of methods, as it felt entirely unnecessary
- Removed clippy utils (obviously...)
- Used some shiny compiler features
(let-else is very handy for lints 👀)
- I also renamed the lint to `for_loop_over_fallibles` (note: no `s`).
I'm not sure what's the naming convention here, so maybe I'm wrong.
don't ICE when normalizing closure input tys
We were ICEing while rendering diagnostics because `universe_causes` is expected to track every universe created in the typeck's infcx.
`normalize_and_add_constraints` doesn't update `universe_causes`
when creating new universes, causing an ICE. Remove it!
Add spans to better track normalization constraints.
Fix couple places where `universe_causes` is not updated correctly to
track newly added universes.
Fixes#102800
~Fixess #99665~ (UPDATE: no longer true; the issue has a different failure path than when this PR was created and should be fixed by #101708, but the changes in this PR are still correct and should prevent potential future ICEs)
