check it more easily; also extend object safety to cover sized types
as well as static methods. This makes it sufficient so that we can
always ensure that `Foo : Foo` holds for any trait `Foo`.
This commit is an implementation of [RFC 503][rfc] which is a stabilization
story for the prelude. Most of the RFC was directly applied, removing reexports.
Some reexports are kept around, however:
* `range` remains until range syntax has landed to reduce churn.
* `Path` and `GenericPath` remain until path reform lands. This is done to
prevent many imports of `GenericPath` which will soon be removed.
* All `io` traits remain until I/O reform lands so imports can be rewritten all
at once to `std::io::prelude::*`.
This is a breaking change because many prelude reexports have been removed, and
the RFC can be consulted for the exact list of removed reexports, as well as to
find the locations of where to import them.
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0503-prelude-stabilization.md
[breaking-change]
Closes#20068
This is a [breaking-change]. The new rules require that, for an impl of a trait defined
in some other crate, two conditions must hold:
1. Some type must be local.
2. Every type parameter must appear "under" some local type.
Here are some examples that are legal:
```rust
struct MyStruct<T> { ... }
// Here `T` appears "under' `MyStruct`.
impl<T> Clone for MyStruct<T> { }
// Here `T` appears "under' `MyStruct` as well. Note that it also appears
// elsewhere.
impl<T> Iterator<T> for MyStruct<T> { }
```
Here is an illegal example:
```rust
// Here `U` does not appear "under" `MyStruct` or any other local type.
// We call `U` "uncovered".
impl<T,U> Iterator<U> for MyStruct<T> { }
```
There are a couple of ways to rewrite this last example so that it is
legal:
1. In some cases, the uncovered type parameter (here, `U`) should be converted
into an associated type. This is however a non-local change that requires access
to the original trait. Also, associated types are not fully baked.
2. Add `U` as a type parameter of `MyStruct`:
```rust
struct MyStruct<T,U> { ... }
impl<T,U> Iterator<U> for MyStruct<T,U> { }
```
3. Create a newtype wrapper for `U`
```rust
impl<T,U> Iterator<Wrapper<U>> for MyStruct<T,U> { }
```
Because associated types are not fully baked, which in the case of the
`Hash` trait makes adhering to this rule impossible, you can
temporarily disable this rule in your crate by using
`#![feature(old_orphan_check)]`. Note that the `old_orphan_check`
feature will be removed before 1.0 is released.
This commit is an implementation of [RFC 526][rfc] which is a change to alter
the definition of the old `fmt::FormatWriter`. The new trait, renamed to
`Writer`, now only exposes one method `write_str` in order to guarantee that all
implementations of the formatting traits can only produce valid Unicode.
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0526-fmt-text-writer.md
One of the primary improvements of this patch is the performance of the
`.to_string()` method by avoiding an almost-always redundant UTF-8 check. This
is a breaking change due to the renaming of the trait as well as the loss of the
`write` method, but migration paths should be relatively easy:
* All usage of `write` should move to `write_str`. If truly binary data was
being written in an implementation of `Show`, then it will need to use a
different trait or an altogether different code path.
* All usage of `write!` should continue to work as-is with no modifications.
* All usage of `Show` where implementations just delegate to another should
continue to work as-is.
[breaking-change]
Closes#20352
This pass performs a second pass of stabilization through the `std::sync`
module, avoiding modules/types that are being handled in other PRs (e.g.
mutexes, rwlocks, condvars, and channels).
The following items are now stable
* `sync::atomic`
* `sync::atomic::ATOMIC_BOOL_INIT` (was `INIT_ATOMIC_BOOL`)
* `sync::atomic::ATOMIC_INT_INIT` (was `INIT_ATOMIC_INT`)
* `sync::atomic::ATOMIC_UINT_INIT` (was `INIT_ATOMIC_UINT`)
* `sync::Once`
* `sync::ONCE_INIT`
* `sync::Once::call_once` (was `doit`)
* C == `pthread_once(..)`
* Boost == `call_once(..)`
* Windows == `InitOnceExecuteOnce`
* `sync::Barrier`
* `sync::Barrier::new`
* `sync::Barrier::wait` (now returns a `bool`)
* `sync::Semaphore::new`
* `sync::Semaphore::acquire`
* `sync::Semaphore::release`
The following items remain unstable
* `sync::SemaphoreGuard`
* `sync::Semaphore::access` - it's unclear how this relates to the poisoning
story of mutexes.
* `sync::TaskPool` - the semantics of a failing task and whether a thread is
re-attached to a thread pool are somewhat unclear, and the
utility of this type in `sync` is question with respect to
the jobs of other primitives. This type will likely become
stable or move out of the standard library over time.
* `sync::Future` - futures as-is have yet to be deeply re-evaluated with the
recent core changes to Rust's synchronization story, and will
likely become stable in the future but are unstable until
that time comes.
[breaking-change]
Doesn't yet converge on a fixed point, but generally works. A better algorithm
will come with the implementation of default type parameter fallback.
If inference fails to determine an exact integral or floating point type, it
will set the type to i32 or f64, respectively.
Closes#16968
Doesn't yet converge on a fixed point, but generally works. A better algorithm
will come with the implementation of default type parameter fallback.
If inference fails to determine an exact integral or floating point type, it
will set the type to i32 or f64, respectively.
Closes#16968
Uses the same approach as https://github.com/rust-lang/rust/pull/17286 (and
subsequent changes making it more correct), where the visitor will skip any
pieces of the AST that are from "foreign code", where the spans don't line up,
indicating that that piece of code is due to a macro expansion.
If this breaks your code, read the error message to determine which feature
gate you should add to your crate.
Closes#18102
[breaking-change]
Uses the same approach as https://github.com/rust-lang/rust/pull/17286 (and
subsequent changes making it more correct), where the visitor will skip any
pieces of the AST that are from "foreign code", where the spans don't line up,
indicating that that piece of code is due to a macro expansion.
If this breaks your code, read the error message to determine which feature
gate you should add to your crate, and bask in the knowledge that your code
won't mysteriously break should you try to use the 1.0 release.
Closes#18102
[breaking-change]
As discovered in #20376, the MSYS shell will silently rewrite arguemnts that
look like unix paths into their windows path counterparts for compatibility, but
the recently added `:kind` syntax added to the `-L` flag does not allow for this
form of rewriting. This means that the syntax can be difficult to use at an MSYS
prompt, as well as causing tests to fail when run manuall right now.
This commit takes the other option presented in the original issue to prefix the
path with `kind=` instead of suffixing it with `:kind`. For consistence, the
`-l` flag is also now migrating to `kind=name`.
This is a breaking change due to the *removal* of behavior with `-L`. All code
using `:kind` should now pass `kind=` for `-L` arguments. This is not currently,
but will become, a breaking change for `-l` flags. The old `name:kind` syntax is
still accepted, but all code should update to `kind=name`.
[breaking-change]
Closes#20376
is still probably wrong since it fails to incorporate the ambiguity
resolution measures that `select` uses. Also, made more complicated by
the fact that trait object types do not impl their own traits yet.
Closes#19949 and rust-lang/rfcs#428
[breaking change]
If you have traits used with objects with static methods, you'll need to move
the static methods to a different trait.
r? @cmr
This pull request adds the `rust-gdb` shell script which starts GDB with Rust pretty printers enabled. The PR also makes `rustc` add a special `.debug_gdb_scripts` ELF section on Linux which tells GDB that the produced binary should use the Rust pretty printers.
Note that at the moment this script will only work and be installed on Linux. On Mac OS X there's `rust-lldb` which works much better there. On Windows I had too many problems making this stable. I'll give it another try soonish.
You can use this script just like you would use GDB from the command line. It will use the pretty printers from the Rust "installation" found first in PATH. E.g. if you have `~/rust/x86_64-linux-gnu/stage1/bin` in your path, it will use the pretty printer scripts in `~/rust/x86_64-linux-gnu/stage1/lib/rustlib/etc`.
Rewrite associated types to use projection rather than dummy type parameters. This closes almost every (major) open issue, but I'm holding off on that until the code has landed and baked a bit. Probably it should have more tests, as well, but I wanted to get this landed as fast as possible so that we can collaborate on improving it.
The commit history is a little messy, particularly the merge commit at the end. If I get some time, I might just "reset" to the beginning and try to carve up the final state into logical pieces. Let me know if it seems hard to follow. By far the most crucial commit is "Implement associated type projection and normalization."
r? @nick29581
