Clarify the difference between get_mut and into_mut for OccupiedEntry
The examples for both hash_map::OccupiedEntry::get_mut and
hash_map::OccupiedEntry::into_mut were almost identical. This led to some
confusion over the difference, namely why you would ever use get_mut when
into_mut gives alonger lifetime. Reddit thread:
https://www.reddit.com/r/rust/comments/8a5swr/why_does_hashmaps
This commit adds two lines and a comment to the example, to show that the
entry object can be re-used after calling get_mut.
Closes https://github.com/rust-lang/rust/issues/49745
Make Layout's align a NonZeroUsize
This PR makes the `Layout`'s align field a `NonZeroUsize` since it cannot ever be zero, not even while building a `Layout`. It also contains some drive-by minor cleanups over the docs and the code, like updating the documented error types, or using the `size()` and `align()` methods instead of accessing the fields directly (the latter was required for the `NonZeroUsize` change anyways).
r? @SimonSapin
cc @Amanieu
The examples for both hash_map::OccupiedEntry::get_mut and
hash_map::OccupiedEntry::into_mut were almost identical. This led
to some confusion over the difference, namely why you would ever
use get_mut when into_mut gives alonger lifetime. Reddit thread:
https://www.reddit.com/r/rust/comments/8a5swr/why_does_hashmaps
This commit adds two lines and a comment to the example, to show
that the entry object can be re-used after calling get_mut.
Fix typos of ‘ambiguous’
I had trouble finding this code because of the typo after it was [referenced in a tweet](https://twitter.com/bstrie/status/1002751044605153280). Also fixes an identical but unrelated typo in a comment.
Add as_nanos function to Duration
Duration has historically lacked a way to get the actual number of nanoseconds it contained as a normal Rust type because u64 was of insufficient range, and f64 of insufficient precision. The u128 type solves both issues, so I propose adding an `as_nanos` function to expose the capability.
Fix building rustc on and for musl hosts.
This fixes all problems I had when trying to compile rustc on a musl-based distribution (with `crt-static = false` in `config.toml`).
This is a fixed version of what ended up being #50105, making it possible to compile rustc on musl targets.
The differences to the old (now merged and subsequently reverted) pull request are:
- The commit (6d9154a830) that caused the regression for which the original commits were reverted in #50709 is left out. This means the corresponding bug #36710 is still not fixed with `+crt-static`.
- The test for issue 36710 is skipped for musl targets (until the issue is properly fixed).
- Building cargo-vendor if `crt-static = false` is needed was broken (cargo-vendor links to some shared libraries if they exist on the system and this produces broken binaries with `+crt-static`)
CC @alexcrichton
merge unused-extern-crate and unnecessary-extern-crate lints
Extend the `unused_extern_crates` lint to offer a suggestion to remove the extern crate and remove the `unnecessary_extern_crate` lint.
Still a few minor issues to fix:
- [x] this *does* now leave a blank line... (defer to https://github.com/rust-lang/rust/issues/51176)
- idea: extend the span to be replaced by 1 character if the next character is a `\n`
- [x] what about macros? do we need to watch out for that? (defer to https://github.com/rust-lang/rust/issues/48704)
- [x] also it doesn't work for `extern crate foo; fn main() { foo::bar(); }`
- this is subtle: the `foo` might be shadowing a glob import too, can't always remove
- defer to https://github.com/rust-lang/rust/issues/51177
- [x] we also don't do the `pub use` rewrite thang (https://github.com/rust-lang/rust/issues/51013)
Spun off from https://github.com/rust-lang/rust/pull/51010Fixes#50672
r? @alexcrichton
