Following traits are now diagnostic items:
- `From` (unchanged)
- `Into`
- `TryFrom`
- `TryInto`
This also adds symbols for those items:
- `into_trait`
- `try_from_trait`
- `try_into_trait`
Expand docs on Iterator::intersperse
Unstable feature in #79524. This expands on the docs to bring them more in line with how other methods of `Iterator` are demonstrated.
Stability oddity with const intrinsics
cc `@RalfJung`
In https://github.com/rust-lang/rust/pull/80699#discussion_r551495670 `@usbalbin` realized we accepted some intrinsics as `const` without a `#[rustc_const_(un)stable]` attribute. I did some digging, and that example works because intrinsics inherit their stability from their parents... including `#[rustc_const_(un)stable]` attributes. While we may want to fix that (not sure, wasn't there just a MCPed PR that caused this on purpose?), we definitely want tests for it, thus this PR adding tests and some fun tracing statements.
Add NonZeroUn::is_power_of_two
This saves instructions on both new and old machines <https://rust.godbolt.org/z/4fjTMz>
- On the default x64 target (with no fancy instructions available) it saves a few instructions by not needing to also check for zero.
- On newer targets (with BMI1) it uses `BLSR` for super-short assembly.
This can be used for things like checks against alignments stored in `NonZeroUsize`.
Add `as_rchunks` (and friends) to slices
`@est31` mentioned (https://github.com/rust-lang/rust/issues/76354#issuecomment-717027175) that, for completeness, there needed to be an `as_chunks`-like method that chunks from the end (with the remainder at the beginning) like `rchunks` does.
So here's a PR for `as_rchunks: &[T] -> (&[T], &[[T; N]])` and `as_rchunks_mut: &mut [T] -> (&mut [T], &mut [[T; N]])`.
But as I was doing this and copy-pasting `from_raw_parts` calls, I thought that I should extract that into an unsafe method. It started out a private helper, but it seemed like `as_chunks_unchecked` could be reasonable as a "real" method, so I added docs and made it public. Let me know if you think it doesn't pull its weight.
Rollup of 17 pull requests
Successful merges:
- #78455 (Introduce {Ref, RefMut}::try_map for optional projections in RefCell)
- #80144 (Remove giant badge in README)
- #80614 (Explain why borrows can't be held across yield point in async blocks)
- #80670 (TrustedRandomAaccess specialization composes incorrectly for nested iter::Zips)
- #80681 (Clarify what the effects of a 'logic error' are)
- #80764 (Re-stabilize Weak::as_ptr and friends for unsized T)
- #80901 (Make `x.py --color always` apply to logging too)
- #80902 (Add a regression test for #76281)
- #80941 (Do not suggest invalid code in pattern with loop)
- #80968 (Stabilize the poll_map feature)
- #80971 (Put all feature gate tests under `feature-gates/`)
- #81021 (Remove doctree::Import)
- #81040 (doctest: Reset errors before dropping the parse session)
- #81060 (Add a regression test for #50041)
- #81065 (codegen_cranelift: Fix redundant semicolon warn)
- #81069 (Add sample code for Rc::new_cyclic)
- #81081 (Add test for #34792)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
TrustedRandomAaccess specialization composes incorrectly for nested iter::Zips
I found this while working on improvements for TRA.
After partially consuming a Zip adapter and then wrapping it into another Zip where the adapters use their `TrustedRandomAccess` specializations leads to the outer adapter returning elements which should have already been consumed.
If the optimizer gets tripped up by the addition this might affect performance for chained `zip()` iterators even when the inner one is not partially advanced but it would require more extensive fixes to `TrustedRandomAccess` to communicate those offsets earlier.
Included test fails on nightly, [playground link](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=24fa1edf8a104ff31f5a24830593b01f)
implement ptr::write without dedicated intrinsic
This makes `ptr::write` more consistent with `ptr::write_unaligned`, `ptr::read`, `ptr::read_unaligned`, all of which are implemented in terms of `copy_nonoverlapping`.
This means we can also remove `move_val_init` implementations in codegen and Miri, and its special handling in the borrow checker.
Also see [this Zulip discussion](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/ptr.3A.3Aread.20vs.20ptr.3A.3Awrite).
Fix formatting specifiers doc links
d36e3e23a8 seems to have inadvertently changed many of these links to point to `core::fmt` instead of `std::fmt`. The information about formatting specifiers is only documented in [`std::fmt`](https://doc.rust-lang.org/std/fmt/); [`core::fmt`](https://doc.rust-lang.org/core/fmt/) is empty. 3baf6a4a74 seems to have already fixed a couple of these links to point back to `std::fmt`.
Deprecate atomic::spin_loop_hint in favour of hint::spin_loop
For https://github.com/rust-lang/rust/issues/55002
We wanted to leave `atomic::spin_loop_hint` alone when stabilizing `hint::spin_loop` so folks had some time to migrate. This now deprecates `atomic_spin_loop_hint`.
