Currently, the `mpsc::Receiver` offers methods for receiving values in
both blocking (`recv`) and non-blocking (`try_recv`) flavours. However
only blocking iteration over values is supported. This commit adds a
non-blocking iterator to complement the `try_recv` method, just as the
blocking iterator complements the `recv` method.
These types were already `!Sync`, but this improves error messages when
they are used in contexts that require `Sync`, aligning them with
conventions used with `Rc`, among others.
Minimal fix for https://github.com/rust-lang/rust/issues/30563
This covers all the public structs I think; except for Iter and
IntoIter, which I don't know if or how they should be handled.
Minimal fix for https://github.com/rust-lang/rust/issues/30563
This covers all the public structs I think; except for Iter and
IntoIter, which I don't know if or how they should be handled.
The replacements are functions that usually use a single `mem::transmute` in
their body and restrict input and output via more concrete types than `T` and
`U`. Worth noting are the `transmute` functions for slices and the `from_utf8*`
family for mutable slices. Additionally, `mem::transmute` was often used for
casting raw pointers, when you can already cast raw pointers just fine with
`as`.
This commit is an implementation of [RFC 1184][rfc] which tweaks the behavior of
the `#![no_std]` attribute and adds a new `#![no_core]` attribute. The
`#![no_std]` attribute now injects `extern crate core` at the top of the crate
as well as the libcore prelude into all modules (in the same manner as the
standard library's prelude). The `#![no_core]` attribute disables both std and
core injection.
[rfc]: https://github.com/rust-lang/rfcs/pull/1184
This isn't actually necessary any more with the advent of `$crate` and changes
in the compiler to expand macros to `::core::$foo` in the context of a
`#![no_std]` crate.
The libcore inner module was also trimmed down a bit to the bare bones.
An automated script was run against the `.rs` and `.md` files,
subsituting every occurrence of `task` with `thread`. In the `.rs`
files, only the texts in the comment blocks were affected.
This commit brings the `Error` trait in line with the [Error interoperation
RFC](https://github.com/rust-lang/rfcs/pull/201) by adding downcasting,
which has long been intended. This change means that for any `Error`
trait objects that are `'static`, you can downcast to concrete error
types.
To make this work, it is necessary for `Error` to inherit from
`Reflect` (which is currently used to mark concrete types as "permitted
for reflection, aka downcasting"). This is a breaking change: it means
that impls like
```rust
impl<T> Error for MyErrorType<T> { ... }
```
must change to something like
```rust
impl<T: Reflect> Error for MyErrorType<T> { ... }
```
except that `Reflect` is currently unstable (and should remain so for
the time being). For now, code can instead bound by `Any`:
```rust
impl<T: Any> Error for MyErrorType<T> { ... }
```
which *is* stable and has `Reflect` as a super trait. The downside is
that this imposes a `'static` constraint, but that only
constrains *when* `Error` is implemented -- it does not actually
constrain the types that can implement `Error`.
[breaking-change]
Changes the style guidelines regarding unit tests to recommend using a
sub-module named "tests" instead of "test" for unit tests as "test"
might clash with imports of libtest.
This small commit stabilizes the `Error` trait as-is, except that `Send`
and `Debug` are added as constraints. The `Send` constraint is because
most uses of `Error` will be for trait objects, and by default we would
like these objects to be transferrable between threads. The `Debug`
constraint is to ensure that e.g. `Box<Error>` is `Debug`, and because
types that implement `Display` should certainly implement `Debug` in any case.
In the near future we expect to add `Any`-like downcasting features to
`Error`, but this is waiting on some additional
mechanisms (`Reflect`). It will be added before 1.0 via default methods.
[breaking-change]
r? @alexcrichton
Closes#21790
This small commit stabilizes the `Error` trait as-is, except that `Send`
and `Debug` are added as constraints. The `Send` constraint is because
most uses of `Error` will be for trait objects, and by default we would
like these objects to be transferrable between threads. The `Debug`
constraint is to ensure that e.g. `Box<Error>` is `Debug`, and because
types that implement `Display` should certainly implement `Debug` in any case.
In the near future we expect to add `Any`-like downcasting features to
`Error`, but this is waiting on some additional
mechanisms (`Reflect`). It will be added before 1.0 via default methods.
[breaking-change]
