See also X-Link mem::{swap, take, replace}
Since it's easy to end up at one of these functions when you really wanted the other one, cross link them with descriptions of why you'd want to use them.
Don't panic in Vec::shrink_to_fit
We can help the compiler see that `Vec::shrink_to_fit` will never reach the panic case in `RawVec::shrink_to_fit`, just by guarding the call only for cases where the capacity is strictly greater. A capacity less than the length is only possible through an unsafe call to `set_len`, which would break the `Vec` invariants, so `shrink_to_fit` can just ignore that.
This removes the panicking code from the examples in both #71861 and #75636.
Move to intra doc links for ascii.rs and panic.rs
Helps with #75080.
@rustbot modify labels: T-doc, A-intra-doc-links, T-rustdoc
I also updated the doc to fix the wording in `AsciiExt` since it is now deprecated.
The two file are small changes so I bundled them together.
Some links could not be changed to make them work, I believe those are known issues with primitive types.
Add `as_uninit`-like methods to pointer types and unify documentation of `as_ref` methods
This adds a convenient method to retrieve a `&(mut) [MaybeUninit<T>]` from slice pointers (`*const [T]`, `*mut [T]`, `NonNull<[T]>`). See also https://github.com/rust-lang/wg-allocators/issues/66#issuecomment-671789105.
~I'll add a tracking issue as soon as it's reviewed and CI passed.~
Tracking Issue: #75402
r? @RalfJung
Reference lang items during AST lowering
Fixes#60607 and fixes#61019.
This PR introduces `QPath::LangItem` to the HIR and uses it in AST lowering instead of constructing a `hir::Path` from a slice of symbols:
- Credit for much of this work goes to @matthewjasper, I basically just [rebased their earlier work](a227c706b7 (diff-c0f791ead38d2d02916faaad0f56f41d)).
- ~~Changes to Clippy might not be correct, they compile but attempting to run tests through `./x.py` produced failures which appeared spurious, so I didn't run any clippy tests.~~
- Changes to save analysis might not be correct - tests pass but I don't have a lot of confidence in those changes being correct.
- I've used `GenericBounds::LangItemTrait` rather than changing `PolyTraitRef`, as suggested by @matthewjasper [in this comment](a227c706b7 (r40107992)) but I'd prefer that be left for a follow-up.
- I've split things into smaller commits fairly arbitrarily to make the diff easier to review, each commit should compile but might not pass tests until the final commit.
r? @oli-obk
cc @matthewjasper
Fix example in `NonNull::as_uninit_slice`
Rename feature gate to "ptr_as_uninit"
Make methods more consistent with already stable methods
Make `pointer::as_uninit_slice` return an `Option`
Fix placement for `// SAFETY` section
Add `as_uninit_ref` and `as_uninit_mut` to pointers
Fix doctest
Update tracking issue
Fix doc links
Apply suggestions from review
Make wording about counterparts consistent
Fix doc links
Improve documentation
Fix doc-tests
Fix doc links ... again
Apply suggestions from review
Apply suggestions from Review
Apply suggestion from review to all affected files
Add missing words in safety sections in `as_uninit_slice_mut`
Fix safety-comment in `NonNull::as_uninit_slice_mut`
Move to intra-doc links for /library/core/src/any.rs
Helps with #75080.
@rustbot modify labels: T-doc, A-intra-doc-links, T-rustdoc
Known issues:
* Links from `core` to `std` (#74481):
* `[Box]: ../../std/boxed/struct.Box.html`
pin docs: add some forward references
@nagisa had some questions about pinning that were answered in the docs, which they did not realize because that discussion is below the examples. I still think it makes sense to introduce the examples before that discussion, since it give the discussion something concrete to refer to, but this PR adds some forward references so people don't think the examples conclude the docs.
@nagisa do you think this would have helped?
Code blocks in doc comments are compiled and run, so we show `Copy` works in this example.
Co-authored-by: Poliorcetics <poliorcetics@users.noreply.github.com>
Previously checking for `pmoda == 0` would get LLVM to generate branchy
code, when, for `stride = 1` the offset can be computed without such a
branch by doing effectively a `-p % a`.
For well-known (constant) alignments, with the new ordering of these
conditionals, we end up generating 2 to 3 cheap instructions on x86_64:
movq %rdi, %rax
negl %eax
andl $7, %eax
instead of 5+ as previously.
For unknown alignments the new code also generates just 3 instructions:
negq %rdi
leaq -1(%rsi), %rax
andq %rdi, %rax
At opt-level <= 1, the methods such as `wrapping_mul` are not being
inlined, causing significant bloating and slowdowns of the
implementation at these optimisation levels.
With use of these intrinsics, the codegen of this function at
-Copt_level=1 is the same as it is at -Copt_level=3.
In the current documentation about the `Copy` marker trait, there is a section
with examples of structs that can implement `Copy`. Currently there is no example for
showing that shared references (`&T`) are also `Copy`.
It is worth to have a dedicated example for `&T` being `Copy`, because shared
references are an integral part of the language and it being `Copy` is not as
intuitive as other types that share this behaviour like `i32` or `bool`.
The example picks up on the previous non-`Copy` struct and shows that
structs can be `Copy`, even when they hold a shared reference to a non-`Copy` type.
This commit adds new lang items which will be used in AST lowering once
`QPath::LangItem` is introduced.
Co-authored-by: Matthew Jasper <mjjasper1@gmail.com>
Signed-off-by: David Wood <david@davidtw.co>
Move to intra doc links in std::net
Helps with #75080.
@rustbot modify labels: T-doc, A-intra-doc-links, T-rustdoc
The links for `true` and `false` had to stay else `rustdoc` complained, it is intended ?
