Add Collapsible match lint
changelog: Add collapsible_match lint
Closes#1252Closes#2521
This lint finds nested `match` or `if let` patterns that can be squashed together. It is designed to be very conservative to only find cases where merging the patterns would most likely reduce cognitive complexity.
Example:
```rust
match result {
Ok(opt) => match opt {
Some(x) => x,
_ => return,
}
_ => return,
}
```
to
```rust
match result {
Ok(Some(x)) => x,
_ => return,
}
```
These criteria must be met for the lint to fire:
* The inner match has exactly 2 branches.
* Both the outer and inner match have a "wild" branch like `_ => ..`. There is a special case for `None => ..` to also be considered "wild-like".
* The contents of the wild branches are identical.
* The binding which "links" the matches is never used elsewhere.
Thanks to the hir, `if let`'s are easily included with this lint since they are desugared into equivalent `match`'es.
I think this would fit into the style category, but I would also understand changing it to pedantic.
add `internal-lints` feature to enable clippys internal lints (off by default)
This PR moves the internal lint tests into a new subdirectory (I couldn't find a different way to compile-time-conditionally exclude them from compiletest) and only builds and tests internal lints if the `internal-lints` feature is enabled.
Fixes#6306
changelog: put internal lints behind a feature ("internal-lints")
Revert "Auto merge of #79209
r? `@nikomatsakis`
This has caused some issues (#79560) so better to revert and try to come up with a proper fix without rush.
Rustdoc: JSON backend experimental impl, with new tests.
Based on #75114 by `@P1n3appl3`
The first commit is all of #75114, but squased to 1 commit, as that was much easier to rebase onto master.
The git history is a mess, but I think I'll edit it after review, so it's obvious whats new.
## Still to do
- [ ] Update docs.
- [ ] Add bless option to tests.
- [ ] Add test option for multiple files in same crate.
- [ ] Decide if the tests should check for json to be equal or subset.
- [ ] Go through the rest of the review for the original pr. (This is open because the test system is done(ish), but stuff like [not using a hashmap](https://github.com/rust-lang/rust/pull/75114#discussion_r519474420) and [using `CRATE_DEF_INDEX` ](https://github.com/rust-lang/rust/pull/75114#discussion_r519470764) hasn't)
I'm also sure how many of these we need to do before landing on nightly, as it would be nice to get this in tree, so it isn't effected by churn like #79125, #79041, #79061
r? `@jyn514`
unix: Extend UnixStream and UnixDatagram to send and receive file descriptors
Add the functions `recv_vectored_fds` and `send_vectored_fds` to `UnixDatagram` and `UnixStream`. With this functions `UnixDatagram` and `UnixStream` can send and receive file descriptors, by using `recvmsg` and `sendmsg` system call.
Pretty printing would add a `r#` prefix to raw identifiers, which was
not correct. In general I think this change makes sense -
pretty-printing is for showing to the *user*, `item_name` is suitable to
pass to resolve.
Do not show negative polarity trait implementations in diagnostic messages for similar implementations
This fixes#79458.
Previously, this code:
```rust
#[derive(Clone)]
struct Foo<'a, T> {
x: &'a mut T,
}
```
would have suggested that `<&mut T as Clone>` was an implementation that was found. This is due to the fact that the standard library now has `impl<'_, T> !Clone for &'_ mut T`, and explicit negative polarity implementations were not filtered out in diagnostic output when suggesting similar implementations.
This PR fixes this issue by filtering out negative polarity trait implementations in `find_similar_impl_candidates` within `rustc_trait_selection::traits::error_reporting::InferCtxtPrivExt<'tcx>`. It also adds a UI regression test for this issue and fixes UI tests that had incorrectly been modified to expect the invalid output.
r? `@scottmcm`
Use true previous lint level when detecting overriden forbids
Previously, cap-lints was ignored when checking the previous forbid level, which
meant that it was a hard error to do so. This is different from the normal
behavior of lints, which are silenced by cap-lints; if the forbid would not take
effect regardless, there is not much point in complaining about the fact that we
are reducing its level.
It might be considered a bug that even `--cap-lints deny` would suffice to
silence the error on overriding forbid, depending on if one cares about failing
the build or precisely forbid being set. But setting cap-lints to deny is quite
odd and not really done in practice, so we don't try to handle it specially.
This also unifies the code paths for nested and same-level scopes. However, the
special case for CLI lint flags is left in place (introduced by #70918) to fix
the regression noted in #70819. That means that CLI flags do not lint on forbid
being overridden by a non-forbid level. It is unclear whether this is a bug or a
desirable feature, but it is certainly inconsistent. CLI flags are a
sufficiently different "type" of place though that this is deemed out of scope
for this commit.
r? `@pnkfelix` perhaps?
cc #77713 -- not marking as "Fixes" because of the lack of proper unused attribute handling in this PR
std::io: Use sendfile for UnixStream
`UnixStream` was forgotten in #75272 .
Benchmark yields the following results.
Before:
`running 1 test
test sys::unix::kernel_copy::tests::bench_file_to_uds_copy ... bench: 54,399 ns/iter (+/- 6,817) = 2409 MB/s`
After:
`running 1 test
test sys::unix::kernel_copy::tests::bench_file_to_uds_copy ... bench: 18,627 ns/iter (+/- 6,007) = 7036 MB/s`
Warn if `dsymutil` returns an error code
This checks the error code returned by `dsymutil` and warns if it failed. It
also provides the stdout and stderr logs from `dsymutil`, similar to the native
linker step.
I tried to think of ways to test this change, but so far I haven't found a good way, as you'd likely need to inject some nonsensical args into `dsymutil` to induce failure, which feels too artificial to me. Also, https://github.com/rust-lang/rust/issues/79361 suggests Rust is on the verge of disabling `dsymutil` by default, so perhaps it's okay for this change to be untested. In any case, I'm happy to add a test if someone sees a good approach.
Fixes https://github.com/rust-lang/rust/issues/78770
Add wasm32 support to inline asm
There is some contention around inline asm and wasm, and I really only made this to figure out the process of hacking on rustc, but I figured as long as the code existed, it was worth uploading.
cc `@Amanieu`
