A few improvements to the slice docs.
* Simplify `Option::iter_mut` doc example.
* Document 'empty' corner-cases for `slice::{starts_with, ends_with}`.
* Indicate 'true' as code-like.
collections: update docs of slice get() and friends
Resubmit of #38216.
r? @GuillaumeGomez
BTW, instead of closing a PR just because it is old and the team member who offered to fix it up did not have the time to do so, why not ping them instead? (cc @alexcrichton)
PartialEq and PartialOrd between IpAddr and Ipv[46]Addr.
PartialEq was rather useful, so, I figured that I'd implement it. I added PartialOrd for good measure.
E0034: provide disambiguated syntax for candidates
For a given file
```rust
trait A { fn foo(&self) {} }
trait B : A { fn foo(&self) {} }
fn bar<T: B>(a: &T) {
a.foo()
}
```
provide the following output
```
error[E0034]: multiple applicable items in scope
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^ multiple `foo` found
|
note: candidate #1 is defined in the trait `A`
--> file.rs:2:11
|
2 | trait A { fn foo(&self, a: usize) {} }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: to use it here write `A::foo(&a, 1)` instead
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^
note: candidate #2 is defined in the trait `B`
--> file.rs:3:15
|
3 | trait B : A { fn foo(&self, a: usize) {} }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: to use it here write `B::foo(&a, 1)` instead
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^
```
Fix#37767.
Improve the slice iterator's searching methods
Improve all, any, find, position, rposition by explicitly unrolling the loop for the slice iterators.
- Introduce a few extension methods and functions for raw pointers make the new code easy to express
- Introduce helper methods `search_while, rsearch_while` that generalize all the searching methods
LLVM doesn't unroll the loop in `.find()` by default (clang is the same), so performance benefits a lot from explicit unrolling here. An iterator method without conditional exits (like `.fold()`) does not need this on the other hand.
One of the raw pointer extension methods is `fn post_inc(&mut self) -> Self` which is the rustic equivalent of “`ptr++`”, and it is a nice way to express the raw pointer loop (see commit 3).
Specific development notes about `search_while`: I tried both computing an end pointer "rounded" to 4, as well as the `ptrdistance >= 4` loop condition, ptrdistance was better. I tried handling the last 0-3 elements unrolled or with a while loop, the loop was better.
incr.comp.: Delete orphaned work-products.
The new partitioning scheme uncovered a hole in our incr. comp. cache directory garbage collection. So far, we relied on unneeded work products being deleted during the initial cache invalidation phase. However, we the new scheme, we get object files/work products that only contain code from upstream crates. Sometimes this code is not needed anymore (because all callers have been removed from the source) but because nothing that actually influences the contents of these work products had changed, we never deleted them from disk.
r? @nikomatsakis
Merge ObjectSum and PolyTraitRef in AST/HIR + some other refactoring
`ObjectSum` and `PolyTraitRef` are the same thing (list of bounds), they exist separately only due to parser quirks. The second commit merges them.
The first commit replaces `Path` with `Ty` in (not yet supported) equality predicates. They are parsed as types anyway and arbitrary types can always be disguised as paths using aliases, so this doesn't add any new functionality.
The third commit uses `Vec` instead of `P<[T]>` in AST. AST is not immutable like HIR and `Vec`s are more convenient for it, unnecessary conversions are also avoided.
The last commit renames `parse_ty_sum` (which is used for parsing types in general) into `parse_ty`, and renames `parse_ty` (which is used restricted contexts where `+` is not permitted due to operator priorities or other reasons) into `parse_ty_no_plus`.
This is the first part of https://github.com/rust-lang/rust/issues/39085#issuecomment-272743755 and https://github.com/rust-lang/rust/issues/39080 focused on data changes and mechanical renaming, I'll submit a PR with parser changes a bit later.
r? @eddyb
travis: Pass --release-channel=nightly on deploy
This commit passes the `--release-channel=nightly` flag to all images which have
the `DEPLOY` flag set. This means that we'll name artifacts and the compiler
appropriately.
This reworks a bit how arguments are passed, but for now doesn't change what's
already being passed. Eventually we'll want to avoid enabling debug assertions
and llvm assertions for *all* releases, but I figure we can tackle that a little
bit more down the road.
This commit passes the `--release-channel=nightly` flag to all images which have
the `DEPLOY` flag set. This means that we'll name artifacts and the compiler
appropriately.
This reworks a bit how arguments are passed, but for now doesn't change what's
already being passed. Eventually we'll want to avoid enabling debug assertions
and llvm assertions for *all* releases, but I figure we can tackle that a little
bit more down the road.
An update to patterns documentation
As it is written the current pattern page creates a lot of confusion, even for someone with previous rust experience. It's so hard because it introduces an entirely new language feature without explaining. Someone could update it within the span of a few minutes by just explaining the newly introduced feature.
```rust
match c {
x => println!("x: {} c: {}", x, c),
}
```
No where in the book up to this point has it explained that identifiers match patterns with just a name create an irrefutable pattern. The page uses this feature without explanation, it just assumes that readers would immediately understand it. To confuse the issue even further the topic uses this feature to explain shadowing, placing two x's from different scopes and different meanings without ever explaining why there is shadowing.
What follows comes across as utterly nonsensical given everything the reader would know about Rust about this point:
```rust
the result:
x: c c: c
x: x
```
x is c? What? Yes even if you understand that x here is not the x in the previous scope why would x equal 'c' here? What previous chapter explained this? The previous chapter on 'matching' only mentions the catch all '_' and never in any shape or form mentioned that a name here creates an irrefutable pattern and binds a value.
There are numerous examples of people not understanding this section, not finding answers and looking for them online about `x: c c: c`:
https://github.com/rust-lang/book/issues/316https://stackoverflow.com/questions/35563141/match-shadowing-example-in-the-patterns-section-of-the-rust-book-is-very-perplexhttps://users.rust-lang.org/t/confusion-about-match-and-patterns/3937https://www.bountysource.com/issues/38852461-question-on-patterns-section-shadowing-example-existing-book
And a [google search for `rust x: c c: c`](https://www.google.com/search?q=rust+%22x:+c+c:+c%22) finds many more people being tripped up, including people who speak a language other than English. I am confident that this page has resulted in questions on the irc channel more than once. Given rust already has a pretty big learning curve I recommend this be fixed.
I was asked to create PR from where I made this same case in the [rust book repository issue](https://github.com/rust-lang/book/issues/316) (I didn't realize this was a separate project).
