This commit adds support for linting `extern crate` statements for stability
attributes attached to the crate itself. This is likely to be the mechanism used
to deny access to experimental crates that are part of the standard
distribution.
cc #18585
r? @aturon
`eq`, `ne`, `cmp`, etc methods now require one less level of indirection when dealing with `&str`/`&[T]`
``` rust
"foo".ne(&"bar") -> "foo".ne("bar")
slice.cmp(&another_slice) -> slice.cmp(another_slice)
// slice and another_slice have type `&[T]`
```
[breaking-change]
variables in the intracrate case. This requires a deeper distinction
between inter- and intra-crate so as to keep coherence working.
I suspect the best fix is to generalize the recursion check that
exists today, but this requires a bit more refactoring to achieve.
(In other words, where today it says OK for an exact match, we'd want
to not detect exact matches but rather skolemize each trait-reference
fresh and return AMBIG -- but that requires us to make builtin bounds
work shallowly like everything else and move the cycle detection into
the fulfillment context.)
This branch cleans up overloaded operator resolution so that it is strictly based on the traits in `ops`, rather than going through the normal method lookup mechanism. It also adds full support for autoderef to overloaded index (whereas before autoderef only worked for non-overloaded index) as well as for the slicing operators.
This is a [breaking-change]: in the past, we were accepting combinations of operands that were not intended to be accepted. For example, it was possible to compare a fixed-length array and a slice, or apply the `!` operator to a `&int`. See the first two commits in this pull-request for examples.
One downside of this change is that comparing fixed-length arrays doesn't always work as smoothly as it did before. Before this, comparisons sometimes worked due to various coercions to slices. I've added impls for `Eq`, `Ord`, etc for fixed-lengths arrays up to and including length 32, but if the array is longer than that you'll need to either newtype the array or convert to slices. Note that this plays better with deriving in any case than the previous scheme.
Fixes#4920.
Fixes#16821.
Fixes#15757.
cc @alexcrichton
cc @aturon
This is a follow-up to [RFC PR #173](https://github.com/rust-lang/rfcs/pull/173). I was told there that changes like this don't need to go through the RFC process, so I'm submitting this directly.
This PR introduces `ToSocketAddr` trait as defined in said RFC. This trait defines a conversion from different types like `&str`, `(&str, u16)` or even `SocketAddr` to `SocketAddr`. Then this trait is used in all constructor methods for `TcpStream`, `TcpListener` and `UdpSocket`.
This unifies these constructor methods - previously they were using different types of input parameters (TCP ones used `(&str, u16)` pair while UDP ones used `SocketAddr`), which is not consistent by itself and sometimes inconvenient - for example, when the address initially is available as `SocketAddr`, you still need to convert it to string to pass it to e.g. `TcpStream`. This is very prominently demonstrated by the unit tests for TCP functionality. This PR makes working with network objects much like with `Path`, which also uses similar trait to be able to be constructed from `&[u8]`, `Vec<u8>` and other `Path`s.
This is a breaking change. If constant literals were used before, like this:
```rust
TcpStream::connect("localhost", 12345)
```
then the nicest fix is to change it to this:
```rust
TcpStream::connect("localhost:12345")
```
If variables were used before, like this:
```rust
TcpStream::connect(some_address, some_port)
```
then the arguments should be wrapped in another set of parentheses:
```rust
TcpStream::connect((some_address, some_port))
```
`UdpSocket` usages won't break because its constructor method accepted `SocketAddr` which implements `ToSocketAddr`, so `bind()` calls:
```rust
UdpSocket::bind(some_socket_addr)
```
will continue working as before.
I haven't changed `UdpStream` constructor because it is deprecated anyway.
Key points are:
1. `a + b` maps directly to `Add<A,B>`, where `A` and `B` are the types of `a` and `b`.
2. Indexing and slicing autoderefs consistently.
This fixes some metadata/AST encoding problems that lead to ICEs. The way this is currently handled will need revisiting if abstract return types are added, as unboxed closure types from extern crates could show up without being inlined into the local crate.
Closes#16790 (I think this was fixed earlier by accident and just needed a test case)
Closes#18378Closes#18543
r? @pcwalton
