Implement rfc 1789: Conversions from `&mut T` to `&Cell<T>`
I'm surprised that RFC 1789 has not been implemented for several months. Tracking issue: https://github.com/rust-lang/rust/issues/43038
Please note: when I was writing tests for `&Cell<[i32]>`, I found it is not easy to get the length of the contained slice. So I designed a `get_with` method which might be useful for similar cases. This method is not designed in the RFC, and it certainly needs to be reviewed by core team. I think it has some connections with `Cell::update` https://github.com/rust-lang/rust/issues/50186 , which is also in design phase.
rustc: Work around an upstream wasm ThinLTO bug
This commit implements a workaround for an [upstream LLVM bug][1] where custom
sections were accidentally duplicated amongst codegen units when ThinLTO passes
were performed. This is due to the fact that custom sections for wasm are stored
as metadata nodes which are automatically imported into modules when ThinLTO
happens. The fix here is to forcibly delete the metadata node from imported
modules before LLVM has a chance to try to copy it over.
[1]: https://bugs.llvm.org/show_bug.cgi?id=38184
(pnkfelix updated to address tidy, and to change the buffer from
`Vec<DiagnosticBuilder<'errs>>` to a `Vec<Diagnostic>` in order to
avoid painful lifetime maintenance.)
Attach deprecation lint `proc_macro_derive_resolution_fallback` to a specific node id
So it can be `allow`-ed from inside the derive.
cc https://github.com/rust-lang/rust/pull/51952
Don't keep the possibly initialized flow around longer than needed
The possibly initialized flow isn't used after liveness is computed, so don't keep it around. Locally this is about a 10% time win for tuple-stress (which is spending a lot of time calculating flows now that it's not spending so much on liveness).
r? @nikomatsakis
LHS of assign op is invariant
This addresses a bug injected by #45435. That PR changed the way we type-check `LHS <op> RHS` to coerce the LHS to the expected supertype in much the same way that we coerce the RHS.
The problem is that when we have a case of `LHS <op>= RHS`, we do not want to coerce to a supertype; we need the type to remain invariant. Otherwise we risk leaking a value with short-lifetimes into a expression context that needs to satisfy a long lifetime.
Fix#52126
add structured suggestions and fix false-positive for elided-lifetimes-in-paths lint
This adds structured suggestions to the elided-lifetimes-in-paths lint (introduced in Nov. 2017's #46254), prevents it from emitting a false-positive on anonymous (underscore) lifetimes (!), and adds it to the idioms-2018 group (#52041).
~~As an aside, "elided-lifetimes-in-paths" seems like an unfortunate name, because it's not clear exactly what "elided" means. The motivation for this lint (see original issue #45992, and [RFC 2115](e978a8d301/text/2115-argument-lifetimes.md (motivation))) seems to be specifically about not supplying angle-bracketed lifetime arguments to non-`&` types, but (1) the phrase "lifetime elision" has historically also referred to the ability to not supply a lifetime name to `&` references, and (2) an `is_elided` method in the HIR returns true for anoymous/underscore lifetimes, which is _not_ what we're trying to lint here. (That naming confusion is almost certainly what led to the false positive addressed here.) Given that the lint is relatively new and is allow-by-default, is it too late to rename it ... um, _again_ (#50879)?~~
~~This does _not_ address a couple of other false positives discovered in https://github.com/rust-lang/rust/issues/52041#issuecomment-402547901.~~
r? @nikomatsakis
cc @nrc @petrochenkov
Rollup of 11 pull requests
Successful merges:
- #51807 (Deprecation of str::slice_unchecked(_mut))
- #52051 (mem::swap the obvious way for types smaller than the SIMD optimization's block size)
- #52465 (Add CI test harness for `thumb*` targets. [IRR-2018-embedded])
- #52507 (Reword when `_` couldn't be inferred)
- #52508 (Document that Unique::empty() and NonNull::dangling() aren't sentinel values)
- #52521 (Fix links in rustdoc book.)
- #52581 (Avoid using `#[macro_export]` for documenting builtin macros)
- #52582 (Typo)
- #52587 (Add missing backtick in UniversalRegions doc comment)
- #52594 (Run the error index tool against the sysroot libdir)
- #52615 (Added new lines to .gitignore.)
Added new lines to .gitignore.
There are a handful of files that I often find in my local working directories that I never want to commit that aren't covered in the `.gitignore` file:
`/mir_dump`:
Default output location from `-Z mir-dump=all` for a specific test, I can't think of a reason why this should ever be commited.
`tags*`/`TAGS*`:
I use `vim-gutentags` which outputs `tags` and `tags.temp` which I don't want commited. I also collapsed the `TAGS`, `TAGS.vi`, `TAGS.emacs` into `TAGS*`.
`Session.vim`:
I use `vim-obsession` to save my current session in Vim, it outputs a `Session.vim` file, this also shouldn't be commited.
Run the error index tool against the sysroot libdir
Previously when building the error index tool in stage 0 we would
attempt to use stage 0 libraries, but because it depends on rustdoc,
those don't exist: rustdoc is built against stage 1 libraries.
This patch aligns those two and passes the stage 1 libdir to the error
index.
@GuillaumeGomez discovered that this hasn't worked (presumably for a long time now, but not sure).
r? @alexcrichton
The existing elided-lifetimes-in-paths lint (introduced in Nov. 2017's
accd997b5 / #46254) lacked stuctured suggestions and—much more
alarmingly—produced false positives on associated functions (like
`Ref::clone`) and on anonymous '_ lifetimes (!!—yes, the very
anonymous lifetimes that we meant to suggest "instead"). That this
went apparently unnoticed for so long maybe tells you something about
how many people actually bother to flip on allow-by-default lints.
After many hours of good old-fashioned American elbow grease—and a
little help from expert reviewers—it turns out that getting the right
answer is a lot easier if we fire the lint while lowering the Higher
Intermediate Representation.
The lint is promoted to the idioms-2018 group.
Also, in the matter of test filenames, "elided" only has one 'l' (see,
e.g., https://en.wiktionary.org/wiki/elide).
Resolves#52041.
Document that Unique::empty() and NonNull::dangling() aren't sentinel values
The documentation of Unique::empty() and NonNull::dangling() could
potentially suggest that they work as sentinel values indicating a
not-yet-initialized pointer. However, they both declare a non-null
pointer equal to the alignment of the type, which could potentially
reference a valid value of that type (specifically, the first such valid
value in memory). Explicitly document that the return value of these
functions does not work as a sentinel value.
Add CI test harness for `thumb*` targets. [IRR-2018-embedded]
This pull request will do the following (rather trivial) changes:
- Fix#52163. In other words, we enabled `./x.py test src/test/run-make` for `no_std` targets.
- Modify `dist-various-1` Dockerfile.
- CI now performs `run-make` test run on the targets below:
- `thumbv6m-none-eabi`
- `thumbv7m-none-eabi`
- `thumbv7em-none-eabi`
- `thumbv7em-none-eabihf`.
- ~~Add `thumb-none` Dockerfile.~~
- ~~Initially, `thumbv7m-none-eabi`, `thumbv7em-none-eabi` and `thumbv7em-none-eabihf` are included as the tested target. `thumbv6m-none-eabi` is disabled for now because LLVM support is not certain.~~
- ~~Add `thumb-none` to .travis.yml~~
Note:
- `run-make` tests are not implemented yet. This PR is test harness only.
The amount of change is very small, but I'd like to open the pull request while the change is trivial.
Because I'm not very used to pull request process, I want to make a small progress first. This PR will be a foundation for later additions.
CC @kennytm @jamesmunns @nerdyvaishali
Deprecation of str::slice_unchecked(_mut)
Closes#51715
I am not sure if 1.28.0 or 1.29.0 should be used for deprecation version, for now it's 1.28.0.
Additionally I've replaced `slice_unchecked` uses with `get_unchecked`. The only places where this method is still used are `src/liballoc/tests/str.rs` and `src/liballoc/tests/str.rs`.
