docs: Improve char::to_{lower,upper}case examples
Collect the results to a String to make it clear that it will not always
return only one char and add examples showing that.
r? @steveklabnik
Updated README to account for changes in MSYS2
One of the newest versions of MSYS2 now only has one .cmd file which replaces the old bat files. It has to be used to launch the mingw32/64 shell.
docs: simplify wording
It took me more then a moment to decipher "with no non-`'static`" thing :)
"`'static` type" should say the same thing more clearly.
r? @steveklabnik
Remove a gotcha from book/error-handling.md
The book's "Error handling with `Box<Error>`" section talks about `Box<Error>`. In the actual example `Box<Error + Send + Sync>` is used instead so that the corresponding From impls could be used to convert a plain string to an error type. Rust 1.7 added support for conversion from `&str`/`String` to
`Box<Error>`, so this gotcha and later references to it can now be removed.
r? @steveklabnik
Reflect supporting only LLVM 3.7+ in the LLVM wrappers
Based on 12abddb06b, it appears we can drop support for these older LLVM versions. Hopefully, this will make it slightly easier to support the changes needed for LLVM 3.9.
r? @nagisa
/cc @brson
Fix wrong statement in compare_exchange doc
The documentation for `core::sync::atomic::AtomicSomething::compare_exchange` contains a wrong, or imprecise, statement about the return value. It goes:
The return value is a result indicating whether the new value was written and containing
the previous value. On success this value is guaranteed to be equal to `new`.
In the second sentence, `this value` is gramatically understood as referring to `return value` from the first sentence. Due to how CAS works, the returned value is always what was in the atomic variable _before_ the operation occurred, not what was written into it during the operation. Hence, the fixed doc should say:
The return value is a result indicating whether the new value was written and containing
the previous value. On success this value is guaranteed to be equal to `current`.
This version is confirmed by the runnable examples in variants of `AtomicSomething`, e.g.
assert_eq!(some_bool.compare_exchange(true, false, Ordering::Acquire, Ordering::Relaxed),
Ok(true));
where the returned value is `Ok(current)`. This PR fixes all occurrences of this bug I could find.
An alternative solution would be to modify the second sentence so that it refers to the value _written_ into the Atomic rather than what was there before, in which case it would be correct. Example alternative formulation:
On success the value written into the `bool`/`usize`/`whatever` is guaranteed to be equal to `new`.
r? @steveklabnik
Improvements to pattern resolution + some refactoring
Continuation of https://github.com/rust-lang/rust/pull/33929
First commit is a careful rewrite of `resolve_pattern`, pattern path resolution and new binding creation logic is factored out in separate functions, some minor bugs are fixed. Also, `resolve_possibly_assoc_item` doesn't swallow modules now.
Later commits are refactorings, see the comment descriptions.
I intend to continue this work later with better support for `Def::Err` in patterns in post-resolve stages and cleanup of pattern resolution code in type checker.
Fixes https://github.com/rust-lang/rust/issues/32086
Fixes https://github.com/rust-lang/rust/issues/34047 ([breaking-change])
Fixes https://github.com/rust-lang/rust/issues/34074
cc @jseyfried
r? @eddyb
MIR cleanups and predecessor cache
This PR cleans up a few things in MIR and adds a predecessor cache to allow graph algorithms to be run easily.
r? @nikomatsakis
Rewrote "How Safe and Unsafe Interact" Nomicon chapter.
The previous version of the chapter covered a lot of ground, but was a little meandering and hard to follow at times. This draft is intended to be clearer and more direct, while still providing the same information as the previous version.
r? @steveklabnik
Use it instead of a `panic` for inexhaustive matches and correct the
comment. I think we trust our match-generation algorithm enough to
generate these blocks, and not generating an `unreachable` means that
LLVM won't optimize `match void() {}` to an `unreachable`.
Fix issue #34101
Fix issue #34101: do not track subcontent of type with dtor nor gather flags for untracked content.
(Includes a regression test, which needed to go into `compile-fail/`
due to weaknesses when combining `#[deny(warnings)]` with
`tcx.sess.span_warn(..)`)
Refactor away the prelude injection fold
Instead, just inject `#[prelude_import] use [core|std]::prelude::v1::*;` at the crate root while injecting `extern crate [core|std];` and process `#[no_implicit_prelude]` attributes in `resolve`.
r? @nrc
