Added documentation on the remainder (Rem) operator for floating points.
# Description
As has been explained in #57738 the remainder operator on floating points is not clear.
This PR requests adds some information on how the `Rem` / remainder operator on floating points works.
Note also that this description is for both `Rem<f32> for f32` and `Rem<f64> for f64` implementations.
Ps. I wasn't really sure on how to formulate things. So please suggest changes if you have better idea's!
closes#57738
Implement useful steps_between for all integers
We can use `usize::try_from` to convert steps from any size of integer.
This enables a meaningful `size_hint()` for larger ranges, rather than
always just `(0, None)`. Now they return the true `(len, Some(len))`
when it fits, otherwise `(usize::MAX, None)` for overflow.
Remove duplicated code from Iterator::{ne, lt, le, gt, ge}
This PR delegates `Iterator::ne` to `Iterator::eq` and `Iterator::{lt, le, gt, ge}` to `Iterator::partial_cmp`.
Oddly enough, this change actually simplifies the generated assembly [in some cases](https://rust.godbolt.org/z/riBtNe), although I don't understand assembly well enough to see if the longer assembly is doing something clever.
I also added two extremely simple benchmarks:
```
// before
test iter::bench_lt ... bench: 98,404 ns/iter (+/- 21,008)
test iter::bench_partial_cmp ... bench: 62,437 ns/iter (+/- 5,009)
// after
test iter::bench_lt ... bench: 61,757 ns/iter (+/- 8,770)
test iter::bench_partial_cmp ... bench: 62,151 ns/iter (+/- 13,753)
```
I have no idea why the current `lt`/`le`/`gt`/`ge` implementations don't seem to be compiled optimally, but simply having them call `partial_cmp` seems to be an improvement.
See #44729 for a previous discussion.
Stabilize refcell_replace_swap feature
Please be kind, this is my first time contributing. 😄
I noticed #43570 only needs stabilizing (and I need it for a side project I'm working on), so I followed the [guide](https://rust-lang.github.io/rustc-guide/stabilization_guide.html#stabilization-pr) to move things forward.
I'm happy to amend things if needed, let me know!
Add FromStr impl for NonZero types
This is a WIP implementation because I do have some questions regarding the solution.
Somebody should ping the lang team on this I guess.
Please see the annotations on the code for more details.
Closes#58604
Rollup of 12 pull requests
Successful merges:
- #57987 (Fix some AArch64 typos)
- #58581 (Refactor generic parameter encoder functions)
- #58803 (fs::copy() unix: set file mode early)
- #58848 (Prevent cache issues on version updates)
- #59198 (Do not complain about unmentioned fields in recovered patterns)
- #59351 (Include llvm-ar with llvm-tools component)
- #59413 (HirIdify hir::ItemId)
- #59441 (Remove the block on natvis for lld-link.)
- #59448 (Use consistent phrasing for all macro summaries)
- #59456 (Add documentation about `for` used as higher ranked trait bounds)
- #59472 (Document that `std::io::BufReader` discards contents on drop)
- #59474 (Fix link capitalization in documentation of std::io::BufWriter.)
Failed merges:
r? @ghost
Moves test::black_box to core::hint and fix black_box on wasm32 and asm.js
This changes removes a cyclic dependency between the "test" and "libtest"
crates, where "libtest" depends on "test" for "black_box", but "test" depends on
"libtest" for everything else.
I've chosen the "hint" module because there seems to be enough consensus in the
discussion of RFC2360 that this module is where such an intrinsic would belong,
but this PR does not implement that RFC! If that RFC ever gets merged, the API, docs,
etc. of this API will need to change. This PR just move the implementation of the
already existing API.
For backwards compatibility reasons I've chosen to also keep the "test" feature
gate for these instead of adding a new feature gate. If we change the feature
gate, we'll potentially all benchmarks, and while that's something that we could
do, it seems unnecessary to do that now - if RFC2360 gets merged, we'll need to
do that anyways. Backwards compatibility is also why we continue to re-export
"black_box" from the "test" crate.
This PR also fixes black_box on the wasm32 target, which now supports inline assembly, and uses volatile loads on the asm.js target.
r? @Amanieu (cc @rust-lang/libs)
add rustfix-able suggestions to trim_{left,right} deprecations
Fixes#53802 (technically already fixed by #58002, but that issue is about these methods).
Improve the documentation for std::convert (From, Into, AsRef and AsMut)
# Description
In this PR I updated the documentation of From, Into, AsRef and AsMut, as well as the general std::convert module documentation. The discussion in #59163 provided information that was not yet present in the docs, or was not expressed clearly enough. I tried to clarify the examples that were already present in the docs as well as add more information about considered best-practices that came out of the discussion in #59163
@steveklabnik I hope I didn't change too much. This is an initial version! I will scan through everything tomorrow as well again to see if I made any typo's or errors, and maybe make some small changes here and there.
All suggestions are welcome!
closes#59163
We can use `usize::try_from` to convert steps from any size of integer.
This enables a meaningful `size_hint()` for larger ranges, rather than
always just `(0, None)`. Now they return the true `(len, Some(len))`
when it fits, otherwise `(usize::MAX, None)` for overflow.
Demo `FromIterator` short-circuiting
while looking at a FIXME in `FromIterator for Option` and `FromIterator for Result`, I realized that the current documentation does not have example code showing exactly what is meant by "no further elements are taken."
The code snippets provided here are meant to correct that.
