Implements https://github.com/rust-lang/rfcs/pull/192.
In particular:
1. type parameters can have lifetime bounds and objects can close over borrowed values, presuming that they have suitable bounds.
2. objects must have a bound, though it may be derived from the trait itself or from a `Send` bound.
3. all types must be well-formed.
4. type parameters and lifetime parameters may themselves have lifetimes as bounds. Something like `T:'a` means "the type T outlives 'a`" and something like `'a:'b`" means "'a outlives 'b". Outlives here means "all borrowed data has a lifetime at least as long".
This is a [breaking-change]. The most common things you have to fix after this change are:
1. Introduce lifetime bounds onto type parameters if your type (directly or indirectly) contains a reference. Thus a struct like `struct Ref<'a, T> { x: &'a T }` would be changed to `struct Ref<'a, T:'a> { x: &'a T }`.
2. Introduce lifetime bounds onto lifetime parameters if your type contains a double reference. Thus a type like `struct RefWrapper<'a, 'b> { r: &'a Ref<'b, int> }` (where `Ref` is defined as before) would need to be changed to `struct RefWrapper<'a, 'b:'a> { ... }`.
2. Explicitly give object lifetimes in structure definitions. Most commonly, this means changing something like `Box<Reader>` to `Box<Reader+'static>`, so as to indicate that this is a reader without any borrowed data. (Note: you may wish to just change to `Box<Reader+Send>` while you're at it; it's a more restrictive type, technically, but means you can send the reader between threads.)
The intuition for points 1 and 2 is that a reference must never outlive its referent (the thing it points at). Therefore, if you have a type `&'a T`, we must know that `T` (whatever it is) outlives `'a`. And so on.
Closes#5723.
This cleans up blatant lies in the concurrency guide, and modernizes it
a bit. There's a lot more to do, but until I get to it, let's make it a
little bit better.
This cleans up blatant lies in the concurrency guide, and modernizes it
a bit. There's a lot more to do, but until I get to it, let's make it a
little bit better.
This test seems to read freed memory -- the peeked variable points into the queue, but then the pop operation removes the node from the queue and moves the enclosing `T` elsewhere, invalidating the `peeked` pointer.
r? @alexcrichton
As of 8876ce44, `is_sugared_doc` is encoded in metadata, so there is no
need to assume that all `doc` attributes came from sugared comments.
Fixes#15976
We have to specify the module and the function name in the example where
the module shares a crate with the executable as well, so remove the
redundant (and potentially confusing) mention.
For review. Not sure about the link_attrs stuff. Will work on converting all the tests.
extern crate "foobar" as foo;
extern crate foobar as foo;
Implements remaining part of RFC #47.
Addresses issue #16461.
Removed link_attrs from rust.md, they don't appear to be supported by
the parser.
DST coercions and DST fields in structs
The commits are not quite stand alone, I should probably squash them together before landing. In particular if you review the individual commits, then you'll see some scrappy stuff that gets fixed in later commits. But reading the commits in order might be easier to get an overall idea of what is going on.
The first commit includes putting back time zone into our time library - @pcwalton removed that as part of his de-~str'ing, but I had already converted it to use StrBuf, so we may as well leave it in. Update: no longer, this is removed in a later commit.
[breaking-change]
1. The internal layout for traits has changed from (vtable, data) to (data, vtable). If you were relying on this in unsafe transmutes, you might get some very weird and apparently unrelated errors. You should not be doing this! Prefer not to do this at all, but if you must, you should use raw::TraitObject rather than hardcoding rustc's internal representation into your code.
2. The minimal type of reference-to-vec-literals (e.g., `&[1, 2, 3]`) is now a fixed size vec (e.g., `&[int, ..3]`) where it used to be an unsized vec (e.g., `&[int]`). If you want the unszied type, you must explicitly give the type (e.g., `let x: &[_] = &[1, 2, 3]`). Note in particular where multiple blocks must have the same type (e.g., if and else clauses, vec elements), the compiler will not coerce to the unsized type without a hint. E.g., `[&[1], &[1, 2]]` used to be a valid expression of type '[&[int]]'. It no longer type checks since the first element now has type `&[int, ..1]` and the second has type &[int, ..2]` which are incompatible.
3. The type of blocks (including functions) must be coercible to the expected type (used to be a subtype). Mostly this makes things more flexible and not less (in particular, in the case of coercing function bodies to the return type). However, in some rare cases, this is less flexible. TBH, I'm not exactly sure of the exact effects. I think the change causes us to resolve inferred type variables slightly earlier which might make us slightly more restrictive. Possibly it only affects blocks with unreachable code. E.g., `if ... { fail!(); "Hello" }` used to type check, it no longer does. The fix is to add a semicolon after the string.
The privacy pass of the compiler was previously not taking into account the
privacy of foreign items, or bindings to external functions. This commit fixes
this oversight by encoding the visibility of foreign items into the metadata for
each crate.
Any code relying on this will start to fail to compile and the bindings must be
marked with `pub` to indicate that they can be used externally.
Closes#16725
[breaking-change]
If a task is spinning in an accept loop, there is currently no method of gracefully shutting it down. This PR introduces a way to do so by cloning the acceptor and implementing a close_accept method to unblocking any pending acceptor.
As with other I/O methods like this, it is `#[experimental]` from the start and sadly carries with it a good deal of code to support it. Much of the complication is from the fact that you can now concurrently accept on the same socket.
I tried to add a good deal of tests for this change, but another set of eyes is always appreciated!
This commits takes a similar strategy to the previous commit to implement
close_accept and clone for the native win32 pipes implementation.
Closes#15595
This commits implements {Tcp,Unix}Acceptor::{clone,close_accept} methods for
all of librustuv.
This implementation rewrites much of Access, AccessTimeout, and AcceptTimeout to
have type parameter for shared state that all acceptors share (a shared queue of
sockets). The incoming/outgoing channels have been removed as all timeouts and
such are now managed on the event loop rather than concurrently.
This commits implements {Tcp,Unix}Acceptor::{clone,close_accept} methods for
unix. A windows implementation is coming in a later commit.
The clone implementation is based on atomic reference counting (as with all
other clones), and the close_accept implementation is based on selecting on a
self-pipe which signals that a close has been seen.
Current version of rust fails when casting from bool, e.g.
```rust
fn main() {
let _a = false as uint;
let _b = true as uint;
let _c: [bool, ..false as uint];
let _d: [bool, ..true as uint];
// _a and _b work, but _c and _d result in an error
// error: expected constant expr for vector length: can't cast str to uint
}
```
This commit makes it work as expected.
Use ExactSize::len() and defer to its decisions about overly defensive
assertions. Remove the length double-check and simply put a failure
case if the Zip finds an uneven end in .next_back().
Fixing this up since I think I wrote this, and it's been known to
confuse rusties (PR #15886).
