I'm not sure why `core` is on but it's blocking the playpen. Doesn't seem to be needed but I'm not sure. It's not on the playpen template and playpen works on release and nightly.
Seems easier to understand without `take()`.
Explicitely spell out behaviour on overflow for `usize`-returning iterator
functions.
Mention that panics are guaranteed if debug assertions are active, otherwise a
wrong result might be returned.
Specifically, make count, nth, and last call the corresponding methods
on the underlying iterator where possible. This way, if the underlying
iterator has an optimized count, nth, or last implementations (e.g.
slice::Iter), these methods will propagate these optimizations.
Additionally, change Skip::next to take advantage of a potentially
optimized nth method on the underlying iterator.
These implementations were intended to be unstable, but currently the stability
attributes cannot handle a stable trait with an unstable `impl` block. This
commit also audits the rest of the standard library for explicitly-`#[unstable]`
impl blocks. No others were removed but some annotations were changed to
`#[stable]` as they're defacto stable anyway.
One particularly interesting `impl` marked `#[stable]` as part of this commit
is the `Add<&[T]>` impl for `Vec<T>`, which uses `push_all` and implicitly
clones all elements of the vector provided.
Closes#24791
[breaking-change]
These implementations were intended to be unstable, but currently the stability
attributes cannot handle a stable trait with an unstable `impl` block. This
commit also audits the rest of the standard library for explicitly-`#[unstable]`
impl blocks. No others were removed but some annotations were changed to
`#[stable]` as they're defacto stable anyway.
One particularly interesting `impl` marked `#[stable]` as part of this commit
is the `Add<&[T]>` impl for `Vec<T>`, which uses `push_all` and implicitly
clones all elements of the vector provided.
Closes#24791
core: Fix size_hint for signed integer `Range<T>` iterators
There was an overflow bug in .size_hint() for signed iterators, which
produced an hilariously incorrect size or an overflow panic.
Incorrect size is a serious bug since the iterators are marked
ExactSizeIterator. (And leads to abort() on (-1i8..127).collect() when
the collection tries to preallocate too much).
> (-1i8..127).size_hint()
(18446744073709551488, Some(18446744073709551488))
Bug found using quickcheck.
Fixes#24851
There was an overflow bug in .size_hint() for signed iterators, which
produced an hilariously incorrect size or an overflow panic.
Incorrect size is a serious bug since the iterators are marked
ExactSizeIterator. (And leads to abort() on (-1i8..127).collect() when
the collection tries to preallocate too much).
All signed range iterators were affected.
> (-1i8..127).size_hint()
(18446744073709551488, Some(18446744073709551488))
Bug found using quickcheck.
Fixes#24851
This commit removes all the old casting/generic traits from `std::num` that are
no longer in use by the standard library. This additionally removes the old
`strconv` module which has not seen much use in quite a long time. All generic
functionality has been supplanted with traits in the `num` crate and the
`strconv` module is supplanted with the [rust-strconv crate][rust-strconv].
[rust-strconv]: https://github.com/lifthrasiir/rust-strconv
This is a breaking change due to the removal of these deprecated crates, and the
alternative crates are listed above.
[breaking-change]
I found that the current description of `enumerate()` doesn't actually tell you what, specifically, the method does, and you have to look at the example to figure it out. Here's a description that I think is better.
The main change in this patch is removing the use of `Option` inside the
inner loops of those functions to avoid comparisons where one branch
will only trigger on the first pass through the loop.
The included benchmarks go from:
test bench_max ... bench: 372 ns/iter (+/- 118)
test bench_max_by ... bench: 428 ns/iter (+/- 33)
test bench_max_by2 ... bench: 7128 ns/iter (+/- 326)
to:
test bench_max ... bench: 317 ns/iter (+/- 64)
test bench_max_by ... bench: 356 ns/iter (+/- 270)
test bench_max_by2 ... bench: 1387 ns/iter (+/- 183)
Problem noticed in http://www.reddit.com/r/rust/comments/31syce/using_iterators_to_find_the_index_of_the_min_or/
The main change in this patch is removing the use of `Option` inside the
inner loops of those functions to avoid comparisons where one branch
will only trigger on the first pass through the loop.
The included benchmarks go from:
test bench_max ... bench: 372 ns/iter (+/- 118)
test bench_max_by ... bench: 428 ns/iter (+/- 33)
test bench_max_by2 ... bench: 7128 ns/iter (+/- 326)
to:
test bench_max ... bench: 317 ns/iter (+/- 64)
test bench_max_by ... bench: 356 ns/iter (+/- 270)
test bench_max_by2 ... bench: 1387 ns/iter (+/- 183)
Problem noticed in http://www.reddit.com/r/rust/comments/31syce/using_iterators_to_find_the_index_of_the_min_or/
This commit changes `Iterator`'s API by:
* Generalizing bounds from `Iterator` to `IntoIterator` whenever
possible, matching the semantics and ergonomics of `for` loops.
* Tightens up a few method-level bounds so that you get an error
earlier. For example, `rev` did not require `DoubleEndedIterator` even
though the result is only an `Iterator` when the original iterator was
double-ended.
Closes#23587
The bound-tightening is technically a:
[breaking-change]
but no code should break in practice.
A recent change to the implementation of range iterators meant that,
even when stepping by 1, the iterators *always* involved checked
arithmetic.
This commit reverts to the earlier behavior (while retaining the
refactoring into traits).
Fixes#24095Closes#24119
cc #24014
r? @alexcrichton
A recent change to the implementation of range iterators meant that,
even when stepping by 1, the iterators *always* involved checked
arithmetic.
This commit reverts to the earlier behavior (while retaining the
refactoring into traits).
Fixes#24095
cc #24014
In addition to being nicer, this also allows you to use `sum` and `product` for
iterators yielding custom types aside from the standard integers.
Due to removing the `AdditiveIterator` and `MultiplicativeIterator` trait, this
is a breaking change.
[breaking-change]
This is a deprecated attribute that is slated for removal, and it also affects
all implementors of the trait. This commit removes the attribute and fixes up
implementors accordingly. The primary implementation which was lost was the
ability to compare `&[T]` and `Vec<T>` (in that order).
This change also modifies the `assert_eq!` macro to not consider both directions
of equality, only the one given in the left/right forms to the macro. This
modification is motivated due to the fact that `&[T] == Vec<T>` no longer
compiles, causing hundreds of errors in unit tests in the standard library (and
likely throughout the community as well).
Closes#19470
[breaking-change]
* The `io::Seek` trait.
* The `Iterator::{partition, unsip}` methods.
* The `Vec::into_boxed_slice` method.
* The `LinkedList::append` method.
* The `{or_insert, or_insert_with` methods in the `Entry` APIs.
r? @alexcrichton
