Implements RFC 438.
Fixes#19092.
This is a [breaking-change]: change types like `&Foo+Send` or `&'a mut Foo+'a` to `&(Foo+Send)` and `&'a mut (Foo+'a)`, respectively.
r? @brson
This is an initial pass at stabilizing the `iter` module. The module is
fairly large, but is also pretty polished, so most of the stabilization
leaves things as they are.
Some changes:
* Due to the new object safety rules, various traits needs to be split
into object-safe traits and extension traits. This includes `Iterator`
itself. While splitting up the traits adds some complexity, it will
also increase flexbility: once we have automatic impls of `Trait` for
trait objects over `Trait`, then things like the iterator adapters
will all work with trait objects.
* Iterator adapters that use up the entire iterator now take it by
value, which makes the semantics more clear and helps catch bugs. Due
to the splitting of Iterator, this does not affect trait objects. If
the underlying iterator is still desired for some reason, `by_ref` can
be used. (Note: this change had no fallout in the Rust distro except
for the useless mut lint.)
* In general, extension traits new and old are following an [in-progress
convention](rust-lang/rfcs#445). As such, they
are marked `unstable`.
* As usual, anything involving closures is `unstable` pending unboxed
closures.
* A few of the more esoteric/underdeveloped iterator forms (like
`RandomAccessIterator` and `MutableDoubleEndedIterator`, along with
various unfolds) are left experimental for now.
* The `order` submodule is left `experimental` because it will hopefully
be replaced by generalized comparison traits.
* "Leaf" iterators (like `Repeat` and `Counter`) are uniformly
constructed by free fns at the module level. That's because the types
are not otherwise of any significance (if we had `impl Trait`, you
wouldn't want to define a type at all).
Closes#17701
Due to renamings and splitting of traits, this is a:
[breaking-change]
- Add `IntoCow` trait, and put it in the prelude
- Add `is_owned`/`is_borrowed` methods to `Cow`
- Add `CowString`/`CowVec` type aliases (to `Cow<'_, String, str>`/`Cow<'_, Vec, [T]>` respectively)
- `Cow` implements: `Show`, `Hash`, `[Partial]{Eq,Ord}`
- `impl BorrowFrom<Cow<'a, T, B>> for B`
[breaking-change]s:
- `IntoMaybeOwned` has been removed from the prelude
- libcollections: `SendStr` is now an alias to `CowString<'static>` (it was aliased to `MaybeOwned<'static>`)
- libgraphviz:
- `LabelText` variants now wrap `CowString` instead of `MaybeOwned`
- `Nodes` and `Edges` are now type aliases to `CowVec` (they were aliased to `MaybeOwnedVec`)
- libstd/path: `Display::as_maybe_owned` has been renamed to `Display::as_cow` and now returns a `CowString`
- These functions now accept/return `Cow` instead of `MaybeOwned[Vector]`:
- libregex: `Replacer::reg_replace`
- libcollections: `str::from_utf8_lossy`
- libgraphviz: `Id::new`, `Id::name`, `LabelText::pre_escaped_content`
- libstd: `TaskBuilder::named`
r? @aturon
This commit removes the `std::local_data` module in favor of a new
`std::thread_local` module providing thread local storage. The module provides
two variants of TLS: one which owns its contents and one which is based on
scoped references. Each implementation has pros and cons listed in the
documentation.
Both flavors have accessors through a function called `with` which yield a
reference to a closure provided. Both flavors also panic if a reference cannot
be yielded and provide a function to test whether an access would panic or not.
This is an implementation of [RFC 461][rfc] and full details can be found in
that RFC.
This is a breaking change due to the removal of the `std::local_data` module.
All users can migrate to the new thread local system like so:
thread_local!(static FOO: Rc<RefCell<Option<T>>> = Rc::new(RefCell::new(None)))
The old `local_data` module inherently contained the `Rc<RefCell<Option<T>>>` as
an implementation detail which must now be explicitly stated by users.
[rfc]: https://github.com/rust-lang/rfcs/pull/461
[breaking-change]
Closes https://github.com/rust-lang/rust/issues/19077
I would appreciate any guidance on how to write a test for this. I saw some examples in `test/pretty`, but there are different ways to test... With or without `.pp` files, with a `pp-exact` comment, etc.
This breaks code like
```
let t = (42i, 42i);
... t.0::<int> ...;
```
Change this code to not contain an unused type parameter. For example:
```
let t = (42i, 42i);
... t.0 ...;
```
Closes https://github.com/rust-lang/rust/issues/19096
[breaking-change]
r? @aturon
This breaks code like
```
let t = (42i, 42i);
... t.0::<int> ...;
```
Change this code to not contain an unused type parameter. For example:
```
let t = (42i, 42i);
... t.0 ...;
```
Closes https://github.com/rust-lang/rust/issues/19096
[breaking-change]
The struct_variant is not gated anymore. This commit just removes it and the resulting warnings when compiling rust. Now compiles with the snapshot from 11/18 (as opposed to PR #19014)
Use the expected type to infer the argument/return types of unboxed closures. Also, in `||` expressions, use the expected type to decide if the result should be a boxed or unboxed closure (and if an unboxed closure, what kind).
This supercedes PR #19089, which was already reviewed by @pcwalton.
Futureproof Rust for fancier suffixed literals. The Rust compiler tokenises a literal followed immediately (no whitespace) by an identifier as a single token: (for example) the text sequences `"foo"bar`, `1baz` and `1u1024` are now a single token rather than the pairs `"foo"` `bar`, `1` `baz` and `1u` `1024` respectively.
The compiler rejects all such suffixes in the parser, except for the 12 numeric suffixes we have now.
I'm fairly sure this will affect very few programs, since it's not currently legal to have `<literal><identifier>` in a Rust program, except in a macro invocation. Any macro invocation relying on this behaviour can simply separate the two tokens with whitespace: `foo!("bar"baz)` becomes `foo!("bar" baz)`.
This implements [RFC 463](https://github.com/rust-lang/rfcs/blob/master/text/0463-future-proof-literal-suffixes.md), and so closes https://github.com/rust-lang/rust/issues/19088.
This commit applies the stabilization of std::fmt as outlined in [RFC 380][rfc].
There are a number of breaking changes as a part of this commit which will need
to be handled to migrated old code:
* A number of formatting traits have been removed: String, Bool, Char, Unsigned,
Signed, and Float. It is recommended to instead use Show wherever possible or
to use adaptor structs to implement other methods of formatting.
* The format specifier for Boolean has changed from `t` to `b`.
* The enum `FormatError` has been renamed to `Error` as well as becoming a unit
struct instead of an enum. The `WriteError` variant no longer exists.
* The `format_args_method!` macro has been removed with no replacement. Alter
code to use the `format_args!` macro instead.
* The public fields of a `Formatter` have become read-only with no replacement.
Use a new formatting string to alter the formatting flags in combination with
the `write!` macro. The fields can be accessed through accessor methods on the
`Formatter` structure.
Other than these breaking changes, the contents of std::fmt should now also all
contain stability markers. Most of them are still #[unstable] or #[experimental]
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0380-stabilize-std-fmt.md
[breaking-change]
Closes#18904
This adds an optional suffix at the end of a literal token:
`"foo"bar`. An actual use of a suffix in a expression (or other literal
that the compiler reads) is rejected in the parser.
This doesn't switch the handling of numbers to this system, and doesn't
outlaw illegal suffixes for them yet.
This commit applies the stabilization of std::fmt as outlined in [RFC 380][rfc].
There are a number of breaking changes as a part of this commit which will need
to be handled to migrated old code:
* A number of formatting traits have been removed: String, Bool, Char, Unsigned,
Signed, and Float. It is recommended to instead use Show wherever possible or
to use adaptor structs to implement other methods of formatting.
* The format specifier for Boolean has changed from `t` to `b`.
* The enum `FormatError` has been renamed to `Error` as well as becoming a unit
struct instead of an enum. The `WriteError` variant no longer exists.
* The `format_args_method!` macro has been removed with no replacement. Alter
code to use the `format_args!` macro instead.
* The public fields of a `Formatter` have become read-only with no replacement.
Use a new formatting string to alter the formatting flags in combination with
the `write!` macro. The fields can be accessed through accessor methods on the
`Formatter` structure.
Other than these breaking changes, the contents of std::fmt should now also all
contain stability markers. Most of them are still #[unstable] or #[experimental]
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0380-stabilize-std-fmt.md
[breaking-change]
Closes#18904
The trait has an obvious, sensible implementation directly on vectors so
the MemWriter wrapper is unnecessary. This will halt the trend towards
providing all of the vector methods on MemWriter along with eliminating
the noise caused by conversions between the two types. It also provides
the useful default Writer methods on Vec<u8>.
After the type is removed and code has been migrated, it would make
sense to add a new implementation of MemWriter with seeking support. The
simple use cases can be covered with vectors alone, and ones with the
need for seeks can use a new MemWriter implementation.
The trait has an obvious, sensible implementation directly on vectors so
the MemWriter wrapper is unnecessary. This will halt the trend towards
providing all of the vector methods on MemWriter along with eliminating
the noise caused by conversions between the two types. It also provides
the useful default Writer methods on Vec<u8>.
After the type is removed and code has been migrated, it would make
sense to add a new implementation of MemWriter with seeking support. The
simple use cases can be covered with vectors alone, and ones with the
need for seeks can use a new MemWriter implementation.
Came up on IRC that this was a bit unhelpful as to what should actually be *done*. I am new to changing compiler messages, please let me know if there's anything else that needs to be done to accomadate this change.
(My build system is still constantly crashing [Is bors contagious?], so this hasn't been formally `check`ed. I figure it's a simple enough change that any consequences [like compile-fail expected messages?] can be eyeballed by someone more experienced.)
`slice_shift_char` splits a `str` into it's leading `char` and the remainder of the `str`. Currently, it returns a `(Option<char>, &str)` such that:
"bar".slice_shift_char() => (Some('b'), "ar")
"ar".slice_shift_char() => (Some('a'), "r")
"r".slice_shift_char() => (Some('r'), "")
"".slice_shift_char() => (None, "")
This is a little odd. Either a `str` can be split into both a head and a tail or it cannot. So the return type should be `Option<(char, &str)>`. With the current behaviour, in the case of the empty string, the `str` returned is meaningless - it is always the empty string.
This PR changes `slice_shift_char` so that:
"bar".slice_shift_char() => Some(('b', "ar"))
"ar".slice_shift_char() => Some(('a', "r"))
"r".slice_shift_char() => Some(('r', ""))
"".slice_shift_char() => None
Following [the collections reform RFC](https://github.com/rust-lang/rfcs/pull/235), this PR:
* Adds a new `borrow` module to libcore. The module contains traits for borrowing data (`BorrowFrom` and `BorrowFromMut`), generalized cloning (`ToOwned`), and a clone-on-write smartpointer (`Cow`).
* Deprecates the `_equiv` family of methods on `HashMap` and `HashSet` by instead generalizing the "normal" methods like `get` and `remove` to use the new `std::borrow` infrastructure.
* Generalizes `TreeMap`, `TreeSet`, `BTreeMap` and `BTreeSet` to use the new `std::borrow` infrastructure for lookups.
[breaking-change]
This is especially useful for declaring a static with external linkage in an executable. There isn't any way to do that currently since we mark everything in an executable as internal by default.
Also, a quick fix to have the no-compiler-rt target option respected when building staticlibs as well.
groundwork for better performance.
Key points:
- Separate out determining which method to use from actually selecting
a method (this should enable caching, as well as the pcwalton fast-reject strategy).
- Merge the impl selection back into method resolution and don't rely on
trait matching (this should perform better but also is needed to resolve some
kind of conflicts, see e.g. `method-two-traits-distinguished-via-where-clause.rs`)
- Purge a lot of out-of-date junk and coercions from method lookups.
This breaks code that referred to variant names in the same namespace as
their enum. Reexport the variants in the old location or alter code to
refer to the new locations:
```
pub enum Foo {
A,
B
}
fn main() {
let a = A;
}
```
=>
```
pub use self::Foo::{A, B};
pub enum Foo {
A,
B
}
fn main() {
let a = A;
}
```
or
```
pub enum Foo {
A,
B
}
fn main() {
let a = Foo::A;
}
```
[breaking-change]
`slice_shift_char` splits a `str` into it's leading `char` and the remainder
of the `str`. Currently, it returns a `(Option<char>, &str)` such that:
"bar".slice_shift_char() => (Some('b'), "ar")
"ar".slice_shift_char() => (Some('a'), "r")
"r".slice_shift_char() => (Some('r'), "")
"".slice_shift_char() => (None, "")
This is a little odd. Either a `str` can be split into both a head and a
tail or it cannot. So the return type should be `Option<(char, &str)>`.
With the current behaviour, in the case of the empty string, the `str`
returned is meaningless - it is always the empty string.
This commit changes slice_shift_char so that:
"bar".slice_shift_char() => Some(('b', "ar"))
"ar".slice_shift_char() => Some(('a', "r"))
"r".slice_shift_char() => Some(('r', ""))
"".slice_shift_char() => None
[breaking-change]
The examples in the documentation for syntax::ext::deriving::encodable
are outdated, and do not work. To fix this, the following changes are
applied:
- emit_field() -> emit_struct_field()
- read_field() -> read_struct_field()
- Use Result to report errors
- Add the mut keyword to Encoder/Decoder
- Prefer Encodable::encode() to emit_uint
This implements a considerable portion of rust-lang/rfcs#369 (tracked in #18640). Some interpretations had to be made in order to get this to work. The breaking changes are listed below:
[breaking-change]
- `core::num::{Num, Unsigned, Primitive}` have been deprecated and their re-exports removed from the `{std, core}::prelude`.
- `core::num::{Zero, One, Bounded}` have been deprecated. Use the static methods on `core::num::{Float, Int}` instead. There is no equivalent to `Zero::is_zero`. Use `(==)` with `{Float, Int}::zero` instead.
- `Signed::abs_sub` has been moved to `std::num::FloatMath`, and is no longer implemented for signed integers.
- `core::num::Signed` has been removed, and its methods have been moved to `core::num::Float` and a new trait, `core::num::SignedInt`. The methods now take the `self` parameter by value.
- `core::num::{Saturating, CheckedAdd, CheckedSub, CheckedMul, CheckedDiv}` have been removed, and their methods moved to `core::num::Int`. Their parameters are now taken by value. This means that
- `std::time::Duration` no longer implements `core::num::{Zero, CheckedAdd, CheckedSub}` instead defining the required methods non-polymorphically.
- `core::num::{zero, one, abs, signum}` have been deprecated. Use their respective methods instead.
- The `core::num::{next_power_of_two, is_power_of_two, checked_next_power_of_two}` functions have been deprecated in favor of methods defined a new trait, `core::num::UnsignedInt`
- `core::iter::{AdditiveIterator, MultiplicativeIterator}` are now only implemented for the built-in numeric types.
- `core::iter::{range, range_inclusive, range_step, range_step_inclusive}` now require `core::num::Int` to be implemented for the type they a re parametrized over.
Adds a method for printing a fatal error and also a help message to the
parser and uses this in a variety of places to improve error messages.
Closes#12213.
