Stabilise irrefutable if-let and while-let patterns #57535
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This stabilises RFC 2086 (rust-lang#44495). Co-Authored-By: Sebastian Malton <sebastian@malton.name>
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…rns, r=Centril Stabilise irrefutable if-let and while-let patterns This stabilises RFC 2086 (rust-lang#44495). This replaces rust-lang#55639, as we want to stabilise this in time for the beta cut-off. Closes rust-lang#55639. r? @Centril
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Rollup of 26 pull requests Successful merges: - #56425 (Redo the docs for Vec::set_len) - #56906 (Issue #56905) - #57042 (Don't call `FieldPlacement::count` when count is too large) - #57175 (Stabilize `let` bindings and destructuring in constants and const fn) - #57192 (Change std::error::Error trait documentation to talk about `source` instead of `cause`) - #57296 (Fixed the link to the ? operator) - #57368 (Use CMAKE_{C,CXX}_COMPILER_LAUNCHER for ccache) - #57400 (Rustdoc: update Source Serif Pro and replace Heuristica italic) - #57417 (rustdoc: use text-based doctest parsing if a macro is wrapping main) - #57433 (Add link destination for `read-ownership`) - #57434 (Remove `CrateNum::Invalid`.) - #57441 (Supporting backtrace for x86_64-fortanix-unknown-sgx.) - #57450 (actually take a slice in this example) - #57459 (Reference tracking issue for inherent associated types in diagnostic) - #57463 (docs: Fix some 'second-edition' links) - #57466 (Remove outdated comment) - #57493 (use structured suggestion when casting a reference) - #57498 (make note of one more normalization that Paths do) - #57499 (note that FromStr does not work for borrowed types) - #57505 (Remove submodule step from README) - #57510 (Add a profiles section to the manifest) - #57511 (Fix undefined behavior) - #57519 (Correct RELEASES.md for 1.32.0) - #57522 (don't unwrap unexpected tokens in `format!`) - #57530 (Fixing a typographical error.) - #57535 (Stabilise irrefutable if-let and while-let patterns) Failed merges: r? @ghost
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Pkgsrc changes:
* Bump required rust version to build to 1.32.0.
* Adapt patches to changed file locations.
* Since we now patch some more vendor/ modules, doctor the corresponding
.cargo-checksum.json files accordingly
Upstream changes:
Version 1.33.0 (2019-02-28)
==========================
Language
--------
- [You can now use the `cfg(target_vendor)` attribute.][57465] E.g.
`#[cfg(target_vendor="apple")] fn main() { println!("Hello Apple!"); }`
- [Integer patterns such as in a match expression can now be exhaustive.][56362]
E.g. You can have match statement on a `u8` that covers `0..=255` and
you would no longer be required to have a `_ => unreachable!()` case.
- [You can now have multiple patterns in `if let` and `while let`
expressions.][57532] You can do this with the same syntax as a `match`
expression. E.g.
```rust
enum Creature {
Crab(String),
Lobster(String),
Person(String),
}
fn main() {
let state = Creature::Crab("Ferris");
if let Creature::Crab(name) | Creature::Person(name) = state {
println!("This creature's name is: {}", name);
}
}
```
- [You can now have irrefutable `if let` and `while let` patterns.][57535]
Using this feature will by default produce a warning as this behaviour
can be unintuitive. E.g. `if let _ = 5 {}`
- [You can now use `let` bindings, assignments, expression statements,
and irrefutable pattern destructuring in const functions.][57175]
- [You can now call unsafe const functions.][57067] E.g.
```rust
const unsafe fn foo() -> i32 { 5 }
const fn bar() -> i32 {
unsafe { foo() }
}
```
- [You can now specify multiple attributes in a `cfg_attr` attribute.][57332]
E.g. `#[cfg_attr(all(), must_use, optimize)]`
- [You can now specify a specific alignment with the `#[repr(packed)]`
attribute.][57049] E.g. `#[repr(packed(2))] struct Foo(i16, i32);` is a
struct with an alignment of 2 bytes and a size of 6 bytes.
- [You can now import an item from a module as an `_`.][56303] This allows you
to import a trait's impls, and not have the name in the namespace. E.g.
```rust
use std::io::Read as _;
// Allowed as there is only one `Read` in the module.
pub trait Read {}
```
- [You may now use `Rc`, `Arc`, and `Pin` as method receivers][56805].
Compiler
--------
- [You can now set a linker flavor for `rustc` with the `-Clinker-flavor`
command line argument.][56351]
- [The mininum required LLVM version has been bumped to 6.0.][56642]
- [Added support for the PowerPC64 architecture on FreeBSD.][57615]
- [The `x86_64-fortanix-unknown-sgx` target support has been upgraded to
tier 2 support.][57130] Visit the [platform support][platform-support]
page for information on Rust's platform support.
- [Added support for the `thumbv7neon-linux-androideabi` and
`thumbv7neon-unknown-linux-gnueabihf` targets.][56947]
- [Added support for the `x86_64-unknown-uefi` target.][56769]
Libraries
---------
- [The methods `overflowing_{add, sub, mul, shl, shr}` are now `const`
functions for all numeric types.][57566]
- [The methods `rotate_left`, `rotate_right`, and `wrapping_{add, sub, mul,
shl, shr}`
are now `const` functions for all numeric types.][57105]
- [The methods `is_positive` and `is_negative` are now `const` functions for
all signed numeric types.][57105]
- [The `get` method for all `NonZero` types is now `const`.][57167]
- [The methods `count_ones`, `count_zeros`, `leading_zeros`, `trailing_zeros`,
`swap_bytes`, `from_be`, `from_le`, `to_be`, `to_le` are now `const` for all
numeric types.][57234]
- [`Ipv4Addr::new` is now a `const` function][57234]
Stabilized APIs
---------------
- [`unix::FileExt::read_exact_at`]
- [`unix::FileExt::write_all_at`]
- [`Option::transpose`]
- [`Result::transpose`]
- [`convert::identity`]
- [`pin::Pin`]
- [`marker::Unpin`]
- [`marker::PhantomPinned`]
- [`Vec::resize_with`]
- [`VecDeque::resize_with`]
- [`Duration::as_millis`]
- [`Duration::as_micros`]
- [`Duration::as_nanos`]
Cargo
-----
- [Cargo should now rebuild a crate if a file was modified during the initial
build.][cargo/6484]
Compatibility Notes
-------------------
- The methods `str::{trim_left, trim_right, trim_left_matches,
trim_right_matches}` are now deprecated in the standard library, and their
usage will now produce a warning. Please use the `str::{trim_start,
trim_end, trim_start_matches, trim_end_matches}` methods instead.
- The `Error::cause` method has been deprecated in favor of `Error::source`
which supports downcasting.
[55982]: rust-lang/rust#55982
[56303]: rust-lang/rust#56303
[56351]: rust-lang/rust#56351
[56362]: rust-lang/rust#56362
[56642]: rust-lang/rust#56642
[56769]: rust-lang/rust#56769
[56805]: rust-lang/rust#56805
[56947]: rust-lang/rust#56947
[57049]: rust-lang/rust#57049
[57067]: rust-lang/rust#57067
[57105]: rust-lang/rust#57105
[57130]: rust-lang/rust#57130
[57167]: rust-lang/rust#57167
[57175]: rust-lang/rust#57175
[57234]: rust-lang/rust#57234
[57332]: rust-lang/rust#57332
[57465]: rust-lang/rust#57465
[57532]: rust-lang/rust#57532
[57535]: rust-lang/rust#57535
[57566]: rust-lang/rust#57566
[57615]: rust-lang/rust#57615
[cargo/6484]: rust-lang/cargo#6484
[`unix::FileExt::read_exact_at`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html#method.read_exact_at
[`unix::FileExt::write_all_at`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html#method.write_all_at
[`Option::transpose`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.transpose
[`Result::transpose`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.transpose
[`convert::identity`]: https://doc.rust-lang.org/std/convert/fn.identity.html
[`pin::Pin`]: https://doc.rust-lang.org/std/pin/struct.Pin.html
[`marker::Unpin`]: https://doc.rust-lang.org/stable/std/marker/trait.Unpin.html
[`marker::PhantomPinned`]: https://doc.rust-lang.org/nightly/std/marker/struct.PhantomPinned.html
[`Vec::resize_with`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.resize_with
[`VecDeque::resize_with`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.resize_with
[`Duration::as_millis`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_millis
[`Duration::as_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_micros
[`Duration::as_nanos`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_nanos
[platform-support]: https://forge.rust-lang.org/platform-support.html
jperkin
pushed a commit
to TritonDataCenter/pkgsrc
that referenced
this pull request
Jun 20, 2019
Pkgsrc changes:
* Bump required rust version to build to 1.32.0.
* Adapt patches to changed file locations.
* Since we now patch some more vendor/ modules, doctor the corresponding
.cargo-checksum.json files accordingly
Upstream changes:
Version 1.33.0 (2019-02-28)
==========================
Language
--------
- [You can now use the `cfg(target_vendor)` attribute.][57465] E.g.
`#[cfg(target_vendor="apple")] fn main() { println!("Hello Apple!"); }`
- [Integer patterns such as in a match expression can now be exhaustive.][56362]
E.g. You can have match statement on a `u8` that covers `0..=255` and
you would no longer be required to have a `_ => unreachable!()` case.
- [You can now have multiple patterns in `if let` and `while let`
expressions.][57532] You can do this with the same syntax as a `match`
expression. E.g.
```rust
enum Creature {
Crab(String),
Lobster(String),
Person(String),
}
fn main() {
let state = Creature::Crab("Ferris");
if let Creature::Crab(name) | Creature::Person(name) = state {
println!("This creature's name is: {}", name);
}
}
```
- [You can now have irrefutable `if let` and `while let` patterns.][57535]
Using this feature will by default produce a warning as this behaviour
can be unintuitive. E.g. `if let _ = 5 {}`
- [You can now use `let` bindings, assignments, expression statements,
and irrefutable pattern destructuring in const functions.][57175]
- [You can now call unsafe const functions.][57067] E.g.
```rust
const unsafe fn foo() -> i32 { 5 }
const fn bar() -> i32 {
unsafe { foo() }
}
```
- [You can now specify multiple attributes in a `cfg_attr` attribute.][57332]
E.g. `#[cfg_attr(all(), must_use, optimize)]`
- [You can now specify a specific alignment with the `#[repr(packed)]`
attribute.][57049] E.g. `#[repr(packed(2))] struct Foo(i16, i32);` is a
struct with an alignment of 2 bytes and a size of 6 bytes.
- [You can now import an item from a module as an `_`.][56303] This allows you
to import a trait's impls, and not have the name in the namespace. E.g.
```rust
use std::io::Read as _;
// Allowed as there is only one `Read` in the module.
pub trait Read {}
```
- [You may now use `Rc`, `Arc`, and `Pin` as method receivers][56805].
Compiler
--------
- [You can now set a linker flavor for `rustc` with the `-Clinker-flavor`
command line argument.][56351]
- [The mininum required LLVM version has been bumped to 6.0.][56642]
- [Added support for the PowerPC64 architecture on FreeBSD.][57615]
- [The `x86_64-fortanix-unknown-sgx` target support has been upgraded to
tier 2 support.][57130] Visit the [platform support][platform-support]
page for information on Rust's platform support.
- [Added support for the `thumbv7neon-linux-androideabi` and
`thumbv7neon-unknown-linux-gnueabihf` targets.][56947]
- [Added support for the `x86_64-unknown-uefi` target.][56769]
Libraries
---------
- [The methods `overflowing_{add, sub, mul, shl, shr}` are now `const`
functions for all numeric types.][57566]
- [The methods `rotate_left`, `rotate_right`, and `wrapping_{add, sub, mul,
shl, shr}`
are now `const` functions for all numeric types.][57105]
- [The methods `is_positive` and `is_negative` are now `const` functions for
all signed numeric types.][57105]
- [The `get` method for all `NonZero` types is now `const`.][57167]
- [The methods `count_ones`, `count_zeros`, `leading_zeros`, `trailing_zeros`,
`swap_bytes`, `from_be`, `from_le`, `to_be`, `to_le` are now `const` for all
numeric types.][57234]
- [`Ipv4Addr::new` is now a `const` function][57234]
Stabilized APIs
---------------
- [`unix::FileExt::read_exact_at`]
- [`unix::FileExt::write_all_at`]
- [`Option::transpose`]
- [`Result::transpose`]
- [`convert::identity`]
- [`pin::Pin`]
- [`marker::Unpin`]
- [`marker::PhantomPinned`]
- [`Vec::resize_with`]
- [`VecDeque::resize_with`]
- [`Duration::as_millis`]
- [`Duration::as_micros`]
- [`Duration::as_nanos`]
Cargo
-----
- [Cargo should now rebuild a crate if a file was modified during the initial
build.][cargo/6484]
Compatibility Notes
-------------------
- The methods `str::{trim_left, trim_right, trim_left_matches,
trim_right_matches}` are now deprecated in the standard library, and their
usage will now produce a warning. Please use the `str::{trim_start,
trim_end, trim_start_matches, trim_end_matches}` methods instead.
- The `Error::cause` method has been deprecated in favor of `Error::source`
which supports downcasting.
[55982]: rust-lang/rust#55982
[56303]: rust-lang/rust#56303
[56351]: rust-lang/rust#56351
[56362]: rust-lang/rust#56362
[56642]: rust-lang/rust#56642
[56769]: rust-lang/rust#56769
[56805]: rust-lang/rust#56805
[56947]: rust-lang/rust#56947
[57049]: rust-lang/rust#57049
[57067]: rust-lang/rust#57067
[57105]: rust-lang/rust#57105
[57130]: rust-lang/rust#57130
[57167]: rust-lang/rust#57167
[57175]: rust-lang/rust#57175
[57234]: rust-lang/rust#57234
[57332]: rust-lang/rust#57332
[57465]: rust-lang/rust#57465
[57532]: rust-lang/rust#57532
[57535]: rust-lang/rust#57535
[57566]: rust-lang/rust#57566
[57615]: rust-lang/rust#57615
[cargo/6484]: rust-lang/cargo#6484
[`unix::FileExt::read_exact_at`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html#method.read_exact_at
[`unix::FileExt::write_all_at`]: https://doc.rust-lang.org/std/os/unix/fs/trait.FileExt.html#method.write_all_at
[`Option::transpose`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.transpose
[`Result::transpose`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.transpose
[`convert::identity`]: https://doc.rust-lang.org/std/convert/fn.identity.html
[`pin::Pin`]: https://doc.rust-lang.org/std/pin/struct.Pin.html
[`marker::Unpin`]: https://doc.rust-lang.org/stable/std/marker/trait.Unpin.html
[`marker::PhantomPinned`]: https://doc.rust-lang.org/nightly/std/marker/struct.PhantomPinned.html
[`Vec::resize_with`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.resize_with
[`VecDeque::resize_with`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.resize_with
[`Duration::as_millis`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_millis
[`Duration::as_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_micros
[`Duration::as_nanos`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_nanos
[platform-support]: https://forge.rust-lang.org/platform-support.html
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This stabilises RFC 2086 (#44495).
This replaces #55639, as we want to stabilise this in time for the beta cut-off.
Closes #55639.
r? @Centril