Support an explicit annotation for marker traits
From the tracking issue for rust-lang/rfcs#1268:
> It seems obvious that we should make a `#[marker]` annotation. ~ https://github.com/rust-lang/rust/issues/29864#issuecomment-368959441
This PR allows you to put `#[marker]` on a trait, at which point:
- [x] The trait must not have any items ~~All of the trait's items must have defaults~~
- [x] Any impl of the trait must be empty (not override any items)
- [x] But impls of the trait are allowed to overlap
r? @nikomatsakis
This change makes "await" ident an error in 2018 edition without async_await
feature and adds "await" to the 2018 edition keyword lint group that
suggest migration on the 2015 edition.
[NLL] Rework checking for borrows conflicting with drops
Previously, we would split the drop access into multiple checks for each
field of a struct/tuple/closure and through `Box` dereferences. This
changes this to check if the borrow is accessed by the drop in
`places_conflict`.
We also now handle enums containing `Drop` types.
Closes#53569
r? @nikomatsakis
cc @pnkfelix
Previously, we would split the drop access into multiple checks for each
field of a struct/tuple/closure and through `Box` dereferences. This
changes this to check if the borrow is accessed by the drop in
places_conflict.
This also allows us to handle enums in a simpler way, since we don't
have to construct any new places.
When dropping a self-borrowing struct we shouldn't add a "values in a
scope are dropped in the opposite order they are defined" message,
since there is only one value being dropped.
Error now correctly checks whether the borrow that does not live
long enough is being returned before annotating the error with the
arguments and return type from the signature - as this would not be
relevant if the borrow was not being returned.
Enhances annotation logic to properly consider named lifetimes where
lifetime elision rules that were previously implemented would not apply.
Further, adds new help and note messages to diagnostics and highlights
only lifetime when dealing with named lifetimes.
This error can only occur within a function when a borrow of data owned
within the function is returned; and when there are arguments that could
have been returned instead. Therefore, it is always applicable to add a
specific note that links to the relevant rust documentation about
dangling references.
Report when borrow could cause `&mut` aliasing during Drop
We were already issuing an error for the cases where this cropped up, so this is not fixing any soundness holes. The previous diagnostic just wasn't accurately describing the problem in the user's code.
Fix#52059
[NLL] Record more infomation on free region constraints in typeck
Changes:
* Makes the span of the MIR return place point to the return type
* Don't try to use a path to a type alias as a path to the adt it aliases (fixes an ICE)
* Don't claim that `self` is declared outside of the function. [see this test](f2995d5b1a (diff-0c9e6b1b204f42129b481df9ce459d44))
* Remove boring/interesting distinction and instead add a `ConstraintCategory` to the constraint.
* Add categories for implicit `Sized` and `Copy` requirements, for closure bounds, for user type annotations and `impl Trait`.
* Don't use the span of the first statement for Locations::All bounds (even if it happens to work on the tests we have)
Future work:
* Fine tuning the heuristic used to choose the place the report the error.
* Reporting multiple places (behind a flag)
* Better closure bounds reporting. This probably requires some discussion.
r? @nikomatsakis
NLL: disallow creation of immediately unusable variables
Fix#53695
Original description follows
----
This WIP PR is for discussing the impact of fixing #53695 by injecting a fake read in let patterns.
(Travis will fail, at least the `mir-opt` suite is failing in its current state)
Rollup of 16 pull requests
Successful merges:
- #53652 (define copy_within on slices)
- #54261 (Make `dyn` a keyword in the 2018 edition)
- #54280 (remove (more) CAS API from Atomic* types where not natively supported)
- #54323 (rustbuild: drop color handling)
- #54350 (Support specifying edition in doc test)
- #54370 (Improve handling of type bounds in `bit_set.rs`.)
- #54371 (add -Zui-testing to rustdoc)
- #54374 (Make 'proc_macro::MultiSpan' public.)
- #54402 (Use no_default_libraries for all NetBSD flavors)
- #54409 (Detect `for _ in in bar {}` typo)
- #54412 (add applicability to span_suggestion call)
- #54413 (Add UI test for deref recursion limit printing twice)
- #54415 (parser: Tweak function parameter parsing to avoid rollback on succesfull path)
- #54420 (Compress `Liveness` data some more.)
- #54422 (Simplify slice's first(_mut) and last(_mut) with get)
- #54446 (Unify christianpoveda's emails)
Failed merges:
- #54058 (Introduce the partition_dedup/by/by_key methods for slices)
r? @ghost
Add UI test for deref recursion limit printing twice
Closes#38940
Does ``NOTE`` in the test need to be changed to ``HELP`` if its in the stderr?
``help: consider adding a `#![recursion_limit="20"]` attribute to your crate``
It doesn't appear to complaining locally that the line isn't set to ``HELP`` in the test, and the guide says
> HELP and SUGGESTION*
> * Note: SUGGESTION must follow immediately after HELP.
yet there's no concrete suggestion emitted.
r? @estebank
`src/test/ui/extern/extern-const.rs` seems to have an inconsistent behaviour across build configurations, possibly non-deterministically. This is tracked in issue 54388.
For this PR, disable running rustfix on it because it failed on CI, until that issue is fixed.
Add regression test for thread local static mut borrows
FIXME(#54366) - We probably shouldn't allow `#[thread_local] static mut` to get a `'static` lifetime, but for now, we should at least test the behavior that `rustc` currently has.
