This should address issue 45696.
Since we know dropping a box will not access any `&mut` or `&`
references, it is safe to model its destructor as only touching the
contents *owned* by the box.
Note: At some point we may want to generalize this machinery to other
reference and collection types that are "pure" in the same sense as
box. If we add a `&move` reference type, it would probably also fall
into this branch of code. But for the short term, we will be
conservative and restrict this change to `Box<T>` alone.
The code works by recursively descending a deref of the `Box`. We
prevent `visit_terminator_drop` infinite-loop (which can arise in a
very obscure scenario) via a linked-list of seen types.
Note: A similar style stack-only linked-list definition can be found
in `rustc_mir::borrow_check::places_conflict`. It might be good at
some point in the future to unify the two types and put the resulting
definition into `librustc_data_structures/`.
----
One final note: Review feedback led to significant simplification of
logic here.
During review, eddyb RalfJung and I uncovered the heart of why I
needed a so-called "step 2" aka the Shallow Write to the Deref of the
box. It was because the `visit_terminator_drop`, in its base case,
will not emit any write at all (shallow or deep) to a place unless
that place has a need_drop.
So I was encoding a Shallow Write by hand for a `Box<T>`, as a
separate step from recursively descending through `*a_box` (which was
at the time known as "step 1"; it is now the *only* step, apart from
the change to the base case for `visit_terminator_drop` that this
commit now has encoded).
eddyb aruged that *something* should be emitting some sort of write in
the base case here (even a shallow one), of the dropped place, since
by analogy we also emit a write when you *move* a place. That led
to the revision here in this commit.
* (Its possible that this desired write should be attached in some
manner to StorageDead instead of Drop. But in this PR, I tried to
leave the StorageDead logic alone and focus my attention solely on
how Drop(x) is modelled in MIR-borrowck.)
The PR title says `armv5te-unknown-linux-musl`, but it looks like the final code merge renamed the target to `armv5te-unknown-linux-musleabi`. `rustup` reports this as correct as well.
The [Rust Platform Support](https://forge.rust-lang.org/platform-support.html) page needs this added as well, but I'm not certain what codebase that is generated from.
These migration lints aren't all up to par in terms of a good migration
experience. Some, like `unreachable_pub`, hit bugs like #52665 and unprepared
macros to be handled enough of the time. Others like linting against
`#[macro_use]` are swimming upstream in an ecosystem that's not quite ready (and
slightly buggy pending a few current PRs).
The general idea is that we will continue to recommend the `rust_2018_idioms`
lint group as part of the transition guide (as an optional step) but we'll be
much more selective about which lints make it into this group. Only those with a
strong track record of not causing too much churn will make the cut.
cc #52679
rustc: Handle linker diagnostics from LLVM
Previously linker diagnostic were being hidden when two modules were linked
together but failed to link. This commit fixes the situation by ensuring that we
have a diagnostic handler installed and also adds support for handling linker
diagnostics.
The regression check is to make beta promotion easier, so it makes more
sense to use the Tuesday of the release week (T-2) as the end point of the
regression prevention, instead of Thursday (T-0). But since the beta
promotion PR is sent at Tuesday evening at UTC, the protection should
include the whole Tuesday as well, meaning the 6-week cycle will start from
Wednesdays.
This will also move the start of the regression protection week one day
earlier.
Rollup of 30 pull requests
Successful merges:
- #52340 (Document From trait implementations for OsStr, OsString, CString, and CStr)
- #52628 (Cleanup some rustdoc code)
- #52732 (Remove unstable and deprecated APIs)
- #52745 (Update clippy to latest master)
- #52771 (Clarify thread::park semantics)
- #52778 (Improve readability of serialize.rs)
- #52810 ([NLL] Don't make "fake" match variables mutable)
- #52821 (pretty print for std::collections::vecdeque)
- #52822 (Fix From<LocalWaker>)
- #52824 (Fix -Wpessimizing-move warnings in rustllvm/PassWrapper)
- #52825 (Make sure #47772 does not regress)
- #52831 (remove references to AUTHORS.txt file)
- #52842 (update comment)
- #52846 (Add timeout to use of `curl` in bootstrap.py.)
- #52851 (Make the tool_lints actually usable)
- #52853 (Improve bootstrap help on stages)
- #52859 (Use Vec::extend in SmallVec::extend when applicable)
- #52861 (Add targets for HermitCore (https://hermitcore.org) to the Rust compiler and port libstd to it.)
- #52867 (releases.md: fix 2 typos)
- #52870 (Implement Unpin for FutureObj and LocalFutureObj)
- #52876 (run-pass/const-endianness: negate before to_le())
- #52878 (Fix wrong issue number in the test name)
- #52883 (Include lifetime in mutability suggestion in NLL messages)
- #52888 (Use suggestions for shell format arguments)
- #52904 (NLL: sort diagnostics by span)
- #52905 (Fix a typo in unsize.rs)
- #52907 (NLL: On "cannot move out of type" error, print original before rewrite)
- #52914 (Only run the sparc-abi test on sparc)
- #52918 (Backport 1.27.2 release notes)
- #52929 (Update compatibility note for 1.28.0 to be correct)
Failed merges:
r? @ghost
Update compatibility note for 1.28.0 to be correct
You can still put implementations on `dyn Trait + Send + Send`, but it'd be the same as putting them on `dyn Trait + Send`. This is why the error is that there are duplicate definitions in the example.
Only run the sparc-abi test on sparc
It is not required for LLVM to have SPARC target support, so it is
necessary to only run this test when LLVM does support SPARC. Sadly, it
isn’t possible to specify exactly this constraint. Instead, we specify
that this test should run on SPARC host only (it surely is sane
assumption to make that compiler running on a SPARC can generate
SPARC, right?)
Since you cannot specify multiple `only-*` to have it run on both 32-bit
and 64-bit SPARC we pick 64-bit SPARC, because it is exactly what is
being tested by this test.
Fixes#52881
NLL: On "cannot move out of type" error, print original before rewrite
NLL: On "cannot move out of type" error, print original source before rewrite.
* Arguably this change is sometimes injecting noise into the output (namely in the cases where the suggested rewrite is inline with the suggestion and we end up highlighting the original source code). I would not be opposed to something more aggressive/dynamic, like revising the suggestion code to automatically print the original source when necessary (e.g. when the error does not have a span that includes the span of the suggestion).
* Also, as another note on this change: The doc comment for `Diagnostic::span_suggestion` says:
```rust
/// The message
///
/// * should not end in any punctuation (a `:` is added automatically)
/// * should not be a question
/// * should not contain any parts like "the following", "as shown"
```
* but the `:` is *not* added when the emitted line appears out-of-line relative to the suggestion. I find that to be an unfortunate UI experience.
----
As a drive-by fix, also changed code to combine multiple suggestions for a pattern into a single multipart suggestion (which vastly improves user experience IMO).
----
Includes the updates to expected NLL diagnostics.
Fix#52877
NLL: sort diagnostics by span
Sorting the output diagnostics by span is a long planned revision to the NLL diagnostics that we hope will yield a less surprising user experience in some case.
Once we got them buffered, it was trivial to implement. (The hard part is skimming the resulting changes to the diagnostics to make sure nothing broke... Note that I largely rubber-stamped the `#[rustc_regions]` output change.)
Fix#51167
Fix wrong issue number in the test name
I made a mistake in previous PR #52620, second issue number was wrong, changing from #52133 to #52113
r? @kennytm
run-pass/const-endianness: negate before to_le()
`const LE_I128` needs parentheses to negate the value *before* calling
`to_le()`, otherwise it doesn't match the operations performed in the
black-boxed part of the test. This only makes a tangible difference on
big-endian targets.
Add targets for HermitCore (https://hermitcore.org) to the Rust compiler and port libstd to it.
As a start, the port uses the simplest possible configuration (no jemalloc, abort on panic) and makes use of existing Unix-specific code wherever possible.
It adds targets for x86_64 (current main HermitCore platform) and aarch64 (HermitCore platform under development).
Together with the patches to "liblibc" (https://github.com/rust-lang/libc/pull/1048) and llvm (https://github.com/rust-lang/llvm/pull/122), this enables HermitCore applications to be written in Rust.
Use Vec::extend in SmallVec::extend when applicable
As calculated in #52738, `Vec::extend` is much faster than `push`ing to it in a loop. We can take advantage of this method in `SmallVec` too - at least in cases when its underlying object is an `AccumulateVec::Heap`.
~~This approach also accidentally improves the `push` loop of the `AccumulateVec::Array` variant, because it doesn't utilize `SmallVec::push` which performs `self.reserve(1)` with every iteration; this is unnecessary, because we're already reserving the whole space we will be needing by performing `self.reserve(iter.size_hint().0)` at the beginning.~~
Make the tool_lints actually usable
cc #44690
Necessary for rust-lang-nursery/rust-clippy#2955 and rust-lang-nursery/rust-clippy#2977
This PR makes it possible for lint tools (at the moment only for Clippy) to implement the `tool_lints`, like it was documented in #52018.
Because the `declare_lint` macro is pretty cluttered right now, there was not really a good way to add the `tool_name` as an additional argument of the macro. That's why I chose to introduce the new `declare_tool_lint` macro.
The switch from `&str` to `String` in the `lint_groups` `FxHashMap` is because I got weird error messages in the `check_lint_name` method. And the `by_name` field of the `LintStore` also uses `String`.
### What comes with this PR:
If this PR lands and Clippy switches to the `tool_lints`, the currently used methods
```rust
#[cfg_attr(feature = "cargo-clippy", allow(clippy_lint))]
#[allow(unknown_lints, clippy_lint)]
```
to `allow`/`warn`/`deny`/`forbid` Clippy lints, won't have any effects anymore, but also won't produce a warning. That is because the name of `clippy_lint` will then be `clippy::clippy_lint`. (Maybe we can add a clippy lint to search for `cfg_attr` appearances with the `cargo-clippy` feature?)
r? @oli-obk
Add timeout to use of `curl` in bootstrap.py.
Recently we've seen a lot of "30 minutes no output" spurious errors while downloading the bootstrap compiler. This added several timeout options so if the "30 minutes no output" errors were caused by connection or transfer issue, we could fail quicker for curl to retry.
Fix -Wpessimizing-move warnings in rustllvm/PassWrapper
These are producing warnings when building rustc (`warning: moving a local object in a return statement prevents copy elision [-Wpessimizing-move]`).
Fix From<LocalWaker>
This is a follow-up to https://github.com/rust-lang/rust/pull/52640
Fixes `From<LocalWaker>` which is affected by the same accidental drop bug (unless I'm totally mistaken)
r? @cramertj
[NLL] Don't make "fake" match variables mutable
These variables can't be mutated by the user, but since they have names the unused-mut lint thinks that it should check them.
Update clippy to latest master
r? @oli-obk
There is a regression in the version in current nightly that falsely lints `println!` and `writeln!` that use named arguments, thinking all rhs values for the argument expressions are literals even when they are not. This update includes the fix for that.
