Fix intra-doc link resolution failure on re-exporting libstd
Currently, re-exporting libstd items as below will [occur a lot of failures](https://gist.github.com/taiki-e/e33e0e8631ef47f65a74a3b69f456366).
```rust
pub use std::*;
```
Until the underlying issue (#56922) fixed, we can fix that so they don't propagate to downstream crates.
Related: https://github.com/rust-lang/rust/pull/56941 (That PR fixed failures that occur when re-exporting from libcore to libstd.)
r? @QuietMisdreavus
Use iter() for iterating arrays by slice
These `into_iter()` calls will change from iterating references to
values if we ever get `IntoIterator` for arrays, which may break the
code using that iterator. Calling `iter()` is future proof.
These `into_iter()` calls will change from iterating references to
values if we ever get `IntoIterator` for arrays, which may break the
code using that iterator. Calling `iter()` is future proof.
This updates to 0.1.13 for `compiler_builtins`, published to fix a few
issues. The feature changes here are updated because `compiler_builtins`
no longer enables the `c` feature by default but we want to do so
through our build still.
Closes#60747Closes#60782
string: implement From<&String> for String
Allow Strings to be created from borrowed Strings. This is mostly
to make things like passing `&String` to an `impl Into<String>`
parameter frictionless.
Fixes#59827.
Add implementations of last in terms of next_back on a bunch of DoubleEndedIterators
Provided a `DoubleEndedIterator` has finite length, `Iterator::last` is equivalent to `DoubleEndedIterator::next_back`. But searching forwards through the iterator when it's unnecessary is obviously not good for performance. I ran into this on one of the collection iterators.
I tried adding appropriate overloads for a bunch of the iterator adapters like filter, map, etc, but I ran into a lot of type inference failures after doing so.
The other interesting case is what to do with `Repeat`. Do we consider it part of the contract that `Iterator::last` will loop forever on it? The docs do say that the iterator will be evaluated until it returns None. This is also relevant for the adapters, it's trivially easy to observe whether a `Map` adapter invoked its closure a zillion times or just once for the last element.
Document the order of {Vec,VecDeque,String}::retain
It's natural for `retain` to work in order from beginning to end, but
this wasn't actually documented to be the case. If we actually promise
this, then the caller can do useful things like track the index of each
element being tested, as [discussed in the forum][1]. This is now
documented for `Vec`, `VecDeque`, and `String`.
[1]: https://users.rust-lang.org/t/vec-retain-by-index/27697
`HashMap` and `HashSet` also have `retain`, and the `hashbrown`
implementation does happen to use a plain `iter()` order too, but it's
not certain that this should always be the case for these types.
r? @scottmcm
It's natural for `retain` to work in order from beginning to end, but
this wasn't actually documented to be the case. If we actually promise
this, then the caller can do useful things like track the index of each
element being tested, as [discussed in the forum][1]. This is now
documented for `Vec`, `VecDeque`, and `String`.
[1]: https://users.rust-lang.org/t/vec-retain-by-index/27697
`HashMap` and `HashSet` also have `retain`, and the `hashbrown`
implementation does happen to use a plain `iter()` order too, but it's
not certain that this should always be the case for these types.
fix LinkedList invalidating mutable references
The test `test_insert_prev` failed in Miri due to what I consider a bug in `LinkedList`: in various places, `NonNull::as_mut` got called to modify the `prev`/`next` pointers of existing nodes. In particular, the unstable `insert_next` has to modify the `next` pointer of the node that was last handed out by the iterator; to this end it creates a mutable reference to the *entire node* that overlaps with the mutable reference to the node's content that was handed out by the iterator! Thus, the next use if said mutable reference is UB.
In code:
```rust
loop {
match it.next() { // mutable reference handed to us
None => break,
Some(elt) => {
it.insert_next(*elt + 1); // this invalidates `elt` because it creates an overlapping mutable reference
match it.peek_next() {
Some(x) => assert_eq!(*x, *elt + 2), // this use of `elt` now is a use of an invalid pointer
None => assert_eq!(8, *elt),
}
}
}
}
```
This PR fixes that by using `as_ptr` instead of `as_mut`. This avoids invalidating the mutable reference that was handed to the user. I did this in all methods called by iterators, just to be sure.
Cc @Gankro
make liballoc internal test suite mostly pass in Miri
I discovered, to my surprise, that liballoc has two test suites: `liballoc/tests`, and a bunch of stuff embedded directly within liballoc. The latter was not covered by [miri-test-libstd](https://github.com/RalfJung/miri-test-libstd) yet. This disables in Miri the tests that Miri cannot support or runs too slowly.
Allow Strings to be created from borrowed Strings. This is mostly
to make things like passing &String to an `impl Into<String>`
parameter frictionless.
This updates the `Extend` implementations to use `for_each` for many
collections: `BinaryHeap`, `BTreeMap`, `BTreeSet`, `LinkedList`, `Path`,
`TokenStream`, `VecDeque`, and `Wtf8Buf`.
Folding with `for_each` enables better performance than a `for`-loop for
some iterators, especially if they can just forward to internal
iterators, like `Chain` and `FlatMap` do.
Mazdak Farrokhzad