the compiler that assumed two input types to assume two ouputs; we also have to teach `project.rs`
to project `Output` from the unboxed closure and fn traits.
Hi! I added some examples to some SliceExt methods that didn't have any.
I'm looking forward to feedback and I'm happy to change anything-- it looks like the doc conventions are still a bit in flux, based on the discussions going on in [rfc 505](https://github.com/rust-lang/rfcs/pull/505).
I was most unsure about examples for methods that return iterators over slices... I wanted to use asserts on the result of calling `.next()` like in [this permutations example](804c1446b3/src/libcollections/slice.rs (L608-L617)), but then it gets all cluttered up with lifetime stuff... so I went with iterating and printing and mentioning what the expected printed output is like in [this chunks example](804c1446b3/src/libcollections/slice.rs (L297-L304))... any ideas for the best ways to do this are appreciated.
Thank you! ❤️
Don't reallocate when capacity is already equal to length
`Vec::shrink_to_fit()` may be called on vectors that are already the
correct length. Calling out to `reallocate()` in this case is a bad idea
because there is no guarantee that `reallocate()` won't allocate a new
buffer anyway, and based on performance seen in external benchmarks, it
seems likely that it is in fact reallocating a new buffer.
Before:
test string::tests::bench_exact_size_shrink_to_fit ... bench: 45 ns/iter (+/- 2)
After:
test string::tests::bench_exact_size_shrink_to_fit ... bench: 26 ns/iter (+/- 1)
There are two limitations to the macro that this addresses:
1. the expected type is not propagated, coercions don't trigger
2. references inside element expressions don't outlive the `Vec`
Both of these limitations are caused by the block in the
macro expansion, previously needed to trigger a coercion
from `Box<[T; N]>` to `Box<[T]>`, now possible with UFCS.
This commit deprecates `slice`, `slice_from`, `slice_to` and their
mutable variants in favor of slice notation.
The `as_slice` methods are left intact, for now.
[breaking-change]
This commit marks as `#[stable]`:
* The `Index` and `IndexMut` traits. These are stabilized as taking the
index itself *by reference*; after extensive discussion it was
determined that this is a better match with our choices
elsewhere (e.g. making comparison operators auto-reference), and that
the use cases for by-value indices are better handled through
`IndexSet`.
* The `Range`, `RangeFrom` and `RangeTo` structs, introduced for range
notation.
* Various impls of `Index` and `IndexMut`.
The `FullRange` struct is left unstable as we may wish to rename it to
`RangeFull` in the future.
This commit also *removes* the `Step` trait in favor of direct
implementation of iterator traits on ranges for integers. The `Step`
trait was not a terribly useful factoring internally, and it is likely
that external integer types are best off implementing range iterators
directly. It was removed to simplify the API surface. We can always
reintroduce `Step` later if it turns out to be useful.
Due to this removal, this is a:
[breaking-change]
This commit is an implementation of [RFC 565][rfc] which is a stabilization of
the `std::fmt` module and the implementations of various formatting traits.
Specifically, the following changes were performed:
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0565-show-string-guidelines.md
* The `Show` trait is now deprecated, it was renamed to `Debug`
* The `String` trait is now deprecated, it was renamed to `Display`
* Many `Debug` and `Display` implementations were audited in accordance with the
RFC and audited implementations now have the `#[stable]` attribute
* Integers and floats no longer print a suffix
* Smart pointers no longer print details that they are a smart pointer
* Paths with `Debug` are now quoted and escape characters
* The `unwrap` methods on `Result` now require `Display` instead of `Debug`
* The `Error` trait no longer has a `detail` method and now requires that
`Display` must be implemented. With the loss of `String`, this has moved into
libcore.
* `impl<E: Error> FromError<E> for Box<Error>` now exists
* `derive(Show)` has been renamed to `derive(Debug)`. This is not currently
warned about due to warnings being emitted on stage1+
While backwards compatibility is attempted to be maintained with a blanket
implementation of `Display` for the old `String` trait (and the same for
`Show`/`Debug`) this is still a breaking change due to primitives no longer
implementing `String` as well as modifications such as `unwrap` and the `Error`
trait. Most code is fairly straightforward to update with a rename or tweaks of
method calls.
[breaking-change]
Closes#21436
**Breaking change**: `VecMap::into_iter` now consumes the `VecMap`. To fix it you should pass the VecMap by value instead of by reference.
[breaking-change]
r? @Gankro
After PR #19766 added implicit coersions `*mut T -> *const T`, the explicit casts can be removed.
(The number of such casts turned out to be relatively small).
There are a large number of places that incorrectly refer
to deriving in comments, instead of derives.
If someone could look at src/etc/generate-deriving-span-tests.py,
I'm not sure how those tests were passing before/if they were.
`Vec::shrink_to_fit()` may be called on vectors that are already the
correct length. Calling out to `reallocate()` in this case is a bad idea
because there is no guarantee that `reallocate()` won't allocate a new
buffer anyway, and based on performance seen in external benchmarks, it
seems likely that it is in fact reallocating a new buffer.
Before:
test string::tests::bench_exact_size_shrink_to_fit ... bench: 45 ns/iter (+/- 2)
After:
test string::tests::bench_exact_size_shrink_to_fit ... bench: 26 ns/iter (+/- 1)
There are two limitations to the macro that this addresses:
1. the expected type is not propagated, coercions don't trigger
2. references inside element expressions don't outlive the `Vec`
Both of these limitations are caused by the block in the
macro expansion, previously needed to trigger a coercion
from `Box<[T; N]>` to `Box<[T]>`, now possible with UFCS.
This fixes the issues mentioned in https://github.com/rust-lang/rust/pull/21236, as well as the one https://github.com/rust-lang/rust/issues/21230 where `CFG_BOOTSTRAP_KEY` was being set to simply 'N'. It changes the build such that `RUSTC_BOOTSTRAP_KEY` is only exported on -beta and -stable, so that the behavior of the -dev, -nightly, and snapshot compilers is the same everywhere.
Haven't run it completely through 'make check' yet, but the I have verified that the aforementioned issues are fixed.
r? @alexcrichton cc @eddyb
