Dedup auto traits in trait objects.
Fixes#47010
Note that the test file `run-pass/trait-object-auto-dedup.rs` passes before and after this change. It's the `ui` test that changed from compiling to not compiling. Which does make this a breaking change, but I cannot imagine anybody actually being broken by it.
Deny #[cfg] and #[cfg_attr] on generic parameters.
Fix#51279.
Attributes on generic parameters are not expanded, meaning `#[cfg]`, `#[cfg_attr]` and attribute proc macros are entirely ignored on them.
This PR makes using the first two attributes an error, because if they are correctly expanded will affect the AST and change code behavior.
I'm beta-nominating this, because generic parameter attributes are stabilizing in 1.27, and if we did not reserve their usage, we may never be able to repurpose the meaning of these attributes in the Rust 2015 edition.
Remove two redundant .nll.stderr files
It turns out that the diagnostics generated from NLL for these cases are now exactly the same as that produced by AST borrowck, and thus we can just fallback on those `.stderr` files that already exist for AST-borrowck.
Bravo!
(it is a good idea to remove these files, because it slightly reduces the amount of time humans will spend reviewing the .nll.stderr fileset...)
((it *might* be worthwhile trying to change the `compiletest` code to even issue a warning when two such files have equivalent contents... but I am not going so far as to try to implement that right now...))
Add Future and task system to the standard library
This adds preliminary versions of the `std::future` and `std::task` modules in order to unblock development of async/await (https://github.com/rust-lang/rust/issues/50547). These shouldn't be considered as final forms of these libraries-- design questions about the libraries should be left on https://github.com/rust-lang/rfcs/pull/2418. Once that RFC (or a successor) is merged, these APIs will be adjusted as necessary.
r? @aturon
Accept `..` in incorrect position to avoid further errors
We currently give a specific message when encountering a `..` anywhere
other than the end of a pattern. Modify the parser to accept it (while
still emitting the error) so that we don't also trigger "missing fields
in pattern" errors afterwards.
Add suggestions to either remove trailing `,` or moving the `..` to the
end.
Follow up to #49268.
Refactor the const eval diagnostic API
* no longer report "const eval error" for things that have typeck errors
* errors and lints have saner spans and messages
* unified the diagnostic logic (const eval errors were slightly different depending on where they were reported, and there was also code duplication between the different reporters)
* report errors if an erroneous constant is used inside a promoted (fixes most of #50814)
When using `..` somewhere other than the end, parse the rest of the
pattern correctly while still emitting an error.
Add suggestions to either remove trailing `,` or moving the `..` to the
end.
We currently give a specific message when encountering a `..` anywhere
other than the end of a pattern. Modify the parser to accept it (while
still emitting the error) so that we don't also trigger "missing fields
in pattern" errors afterwards.
Check array indices in constant propagation
Previously, uses of constant weren't correctly propagated.
This fixes#48920.
r? @oli-obk because you suggested it
Suggest not mutably borrowing a mutable reference
This PR would (hopefully) solve #45392. I deviated a bit from @estebank's instructions since the error span only included the borrowed expression (e.g. the `b` in `&mut b`). I also didn't check the mutability of the local binding, since this whole case is concerned with an immutable local.
I can see two outstanding questions:
1. `note_immutability_blame` is called in two places, but I only have one test case. I think it covers the call in `report_bckerror`, but I'm not sure how to trigger the call from `report_aliasability_violation`.
2. There is one failing test, where the local binding is `self: &mut Self`. I'm not entirely sure what the correct output should be, but I think the new message should also apply. Unfortunately, since this parameter is parsed differently, its `let_span` covers both the pattern and the type, leading to a wrong suggestion text. I'm not sure how to correctly identify this case.
Do not promote union field accesses
r? @eddyb
technically a breaking change, but the code errored on the previous stable and produces UB + a warning on the current stable. I don't think we need a crater run in that case.
