Fix help docs for -Zallow-features
The arguments for -Zallow-features are comma-separated (`parse_opt_comma_list`), not space separated (`parse_list`).
[RFC 2397] Initial implementation
cc #51992
Because of previous experiences where ppl didn't have the time to review large PRs (or any at all), the implementation of this feature will be delivered in small chunks to hopefully make things faster.
In this initial PR, only the attribute is being declared and gated with ordinary tests.
remove E0280
After looking at #61137 I tried my hand at E0280. I'm unable to find a reasonable example that emits the error. There are a couple of old examples that compile with the current compiler ([#26217](https://github.com/rust-lang/rust/issues/26217), [#42114](https://github.com/rust-lang/rust/issues/42114), [#27113](https://github.com/rust-lang/rust/issues/27113)) and there is a [bug with chalk](b7cdb635c4/src/test/ui/chalkify/bugs/async.rs) that makes it emit the error, with a couple more chalk bugs on zulip.
It seems like the error is supposed to be emitted from unfulfilled where bounds, of which two are related to borrow checking (error in where T: 'a or where 'a: 'b) and thus tend to emit errors like "lifetime may not live long enough" from borrow checking instead. The final case is with type equality constraints (where <T as Iterator>::Item == u32), which is unimplemented ([#20041](https://github.com/rust-lang/rust/issues/20041)). That such different problems are supposed to have the same error code also seems strange to me.
Since the error seems to only be emitted when using chalk I propose to remove it and replace it with an ICE instead. A crater run might be warranted.
Pinging `@jackh726` due to removal of chalk test that now ICEs.
Consider return type when giving various method suggestions
1. Fix a bug in method probe where we weren't normalizing `xform_ret_ty` for non-`impl` method candidates. This shouldn't affect happy-path code, since we only use `xform_ret_ty` when probing methods for diagnostics (I think).
2. Pass the return type expectation down to `lookup_probe`/`probe_for_name` usages in diagnostics. Added a few UI tests to gate against bad suggestions.
3. Make a `FnCtxt::lookup_probe_for_diagnostic` which properly passes down `IsSuggestion(true)`. Should help suppress other weird notes in some corner cases.
Accept old spelling of Fuchsia target triples
The old spelling of Fuchsia target triples was changed in #106429 to add a proper vendor. Because the old spelling is widely used, some projects may need time to migrate their uses to the new triple spelling. The old spelling may eventually be removed altogether.
r? ``@tmandry``
Fix bad import suggestion with nested `use` tree
Fixes#105566Fixes#105373
Ideally, we'd find some way to turn these into structured suggestions -- perhaps on a separate line as a different `use` statement, but I have no idea how to access the span for the whole `use` from this point in the import resolution code.
Because the old spelling is widely used, some projects may need time to
migrate their uses to the new triple spelling. The old spelling may
eventually be removed altogether.
error-code docs improvements (No. 2)
- Added empty error-code docs for `E0208`, `E0640` and `E0717` with the "internal" header as discussed on Discord.
- Wrote docs and UI test for `E0711`, again with the header.
- `tidy` changes are common-sense and make everything pass, `style.rs` hack is annoying though.
r? ```@GuillaumeGomez```
Use FxIndexSet when updating obligation causes in `adjust_fulfillment_errors_for_expr_obligation`
I have no idea how to test this reliably, but I've **manually** verified it fixes the instability in #106417 that isn't due to dtolnay/trybuild#212.
Fixes#106417
Simplify some canonical type alias names
* delete the `Canonicalized<'tcx>` type alias in favor for `Canonical<'tcx>`
* `CanonicalizedQueryResponse` -> `CanonicalQueryResponse`
I don't particularly care about the latter, but it should be consistent. We could alternatively delete the first alias and rename the struct to `Canonicalized`, and then keep the name of `CanonicalizedQueryResponse` untouched.
Move `check_region_obligations_and_report_errors` to `TypeErrCtxt`
Makes sense for this function to live with its sibling `resolve_regions_and_report_errors`, around which it's basically just a wrapper.
Enable Shadow Call Stack for Fuchsia on AArch64
Fuchsia already uses SCS by default for C/C++ code on ARM hardware. This patch allows SCS to be used for Rust code as well.
Remove invalid case for mutable borrow suggestion
If we have a call such as `foo(&mut buf)` and after reference
collapsing the type is inferred as `&T` where-as the required type is
`&mut T`, don't suggest `foo(&mut mut buf)`. This is wrong syntactically
and the issue lies elsewhere, not in the borrow.
Fixes#105645
Change a commit_if_ok call to probe
Removes an over-eager `commit_if_ok` which makes inference worse.
I'm not entirely sure whether it's ok to remove the check that types are the same, because casting seems to cause equality checks with incorrect types?
Fixes#105037
r? ```@BoxyUwU```
Always permit ConstProp to exploit arithmetic identities
Fixes https://github.com/rust-lang/rust/issues/72751
Initially, I thought I would need to enable operand propagation then do something else, but actually https://github.com/rust-lang/rust/pull/74491 already has the fix for the issue in question! It looks like this optimization was put under MIR opt level 3 due to possible soundness/stability implications, then demoted further to MIR opt level 4 when MIR opt level 2 became associated with `--release`.
Perhaps in the past we were doing CTFE on optimized MIR? We aren't anymore, so this optimization has no stability implications.
r? `@oli-obk`
Simplify match statement
Add multiple tests
- 1 test for checking `N + 1 + 1` does not unify with `N+1`
- 2 tests for checking that a function that uses two parameters only returns the parameter that
is actually used.
- Check exact repeat predicates
Instead of just switching to a probe, check for different matches, and see how many there are.
If one, unify it, otherwise return true and let it be unified later.
