The requirements `T: Send` and `T: Send + Sync` for `Mutex` and `RwLock`
respectively only matter if those types are shared/sent across thread
boundaries, and that is adequately controlled by the impls of
`Send`/`Sync` for them. If `T` doesn't satisfy the bounds, then
the types cannot cross thread boundaries and so everything is still
safe (the two types just act like an expensive `RefCell`).
The requirement `T: Send + Sync` only matters if the `Arc` crosses
thread boundaries, and that is adequately controlled by the impls of
`Send`/`Sync` for `Arc` itself. If `T` doesn't satisfy the bounds, then
the `Arc` cannot cross thread boundaries and so everything is still
safe (`Arc` just acts like an expensive `Rc`).
This is a hack, but I don't think we can do much better as long as `derive` is running at the syntax expansion phase.
If the `custom_derive` feature gate is enabled, this works with user-defined traits and syntax extensions. Without the gate, you can't use e.g. `#[derive_Clone]` directly, so this does not change the stable language.
To make this effective, we now check gated attributes both before and after macro expansion. This uncovered a number of tests that were missing feature gates.
This PR also cleans up the deriving code somewhat, and forbids some previously-meaningless attribute syntax. For this reason it's technically a
[breaking-change]
r? @sfackler
We require the *deferred* loading, not just an opportunistic asynchronous loading. (Yes, that was my oversight, as I only checked it locally...) I think `<script defer>` is safe to use, according to <http://caniuse.com/#feat=script-defer>.
We require the *deferred* loading, not just an opportunistic
asynchronous loading. I think `<script defer>` is safe to use,
according to <http://caniuse.com/#feat=script-defer>.
This is a hack, but I don't think we can do much better as long as `derive` is
running at the syntax expansion phase.
If the custom_derive feature gate is enabled, this works with user-defined
traits and syntax extensions. Without the gate, you can't use e.g. #[derive_Clone]
directly, so this does not change the stable language.
This commit also cleans up the deriving code somewhat, and forbids some
previously-meaningless attribute syntax. For this reason it's technically a
[breaking-change]
Being a person who somehow has taken a liking to premature optimisation, my knee-jerk reaction to
locking in std handles was preamble resembling following snippet:
let stdout = stdout();
let lstdout = stdout.lock();
let stdin = stdin();
let lstdin = stdin.lock();
and then reading from the locked handle like this:
let mut letter = [0; 1];
lstdin.read(&mut letter).unwrap();
As it is now this code will deadlock because the `read` method attempts to lock stdout as well!
r? @alexcrichton
---
Either way, I find flushing stdout when stdin is used debatable. I believe people who write prompts should take care to flush stdout when necessary themselves.
Another idea: Would be cool if locks on std handles would be taken for a thread, rather than a handle, so given preamble (first code snippet)
stdin.lock()
or more generally
stdin.read(…)
worked fine. I.e. if more than a single lock are all taken inside the same thread, it would work, though not sure if our synchronisation primitives are expressive enough to make it possible.
The `std::net` primitives should be ready for use now and as a result the old
ones are now deprecated and slated for removal. Most TCP/UDP functionality is
now available through `std::net` but the `std::old_io::net::pipe` module is
removed entirely from the standard library.
Unix socket funtionality can be found in sfackler's [`unix_socket`][unix] crate
and there is currently no replacement for named pipes on Windows.
[unix]: https://crates.io/crates/unix_socket
[breaking-change]
Executing `configure` seems to create the following error due to how the script [parses Pandoc's version](https://github.com/rust-lang/rust/blob/master/configure#L705):
```text
./configure: line 705: [: pandoc: integer expression expected
./configure: line 705: [: 1.12.4.2: integer expression expected
```
This issue seems to stem from a discrepancy between BSD and GNU versions of sed. This patch changes the sed command to use an extended regex, which works with both flavours of sed.
The `std::net` primitives should be ready for use now and as a result the old
ones are now deprecated and slated for removal. Most TCP/UDP functionality is
now available through `std::net` but the `std::old_io::net::pipe` module is
removed entirely from the standard library.
Unix socket funtionality can be found in sfackler's [`unix_socket`][unix] crate
and there is currently no replacement for named pipes on Windows.
[unix]: https://crates.io/crates/unix_socket
[breaking-change]
Executing `configure` seems to create the following error due to how the script [parses Pandoc's version](https://github.com/rust-lang/rust/blob/master/configure#L705):
```text
./configure: line 705: [: pandoc: integer expression expected
./configure: line 705: [: 1.12.4.2: integer expression expected
```
This issue seems to stem from a discrepancy between BSD and GNU versions of sed. This patch changes the sed command to use an extended regex, which works with both flavours of sed.
This should fix#22615. Previously, the playpen links grabbed the content of all `.rusttest` containers on the same level to build the URL. Now they just select the one before the `pre` they are shown in.
I have only tested this by changing the file in my local build of the docs (not by running rustdoc itself).
This concretely improves type inference of some cases (see included
test). I assume the compiler struggles to reason about multiple layers
of generic type parameters (even with associated-type equalities) but
*can* understand pure associated types, since they are always directly
computable from the input types.
Thanks to @shepmaster for noticing the issue with `Cloned` (I took that example as a test case).
Being a person who somehow has taken a liking to premature optimisation, my knee-jerk reaction to
locking in std handles was preamble resembling following snippet:
let stdout = stdout();
let lstdout = stdout.lock();
let stdin = stdin();
let lstdin = stdin.lock();
and then reading from the locked handle like this:
let mut letter = [0; 1];
lstdin.read(&mut letter).unwrap();
As it is now this code will deadlock because the `read` method attempts to lock stdout as well!
Unstable items used in a macro expansion will now always trigger
stability warnings, *unless* the unstable items are directly inside a
macro marked with `#[allow_internal_unstable]`. IOW, the compiler warns
unless the span of the unstable item is a subspan of the definition of a
macro marked with that attribute.
E.g.
#[allow_internal_unstable]
macro_rules! foo {
($e: expr) => {{
$e;
unstable(); // no warning
only_called_by_foo!();
}}
}
macro_rules! only_called_by_foo {
() => { unstable() } // warning
}
foo!(unstable()) // warning
The unstable inside `foo` is fine, due to the attribute. But the
`unstable` inside `only_called_by_foo` is not, since that macro doesn't
have the attribute, and the `unstable` passed into `foo` is also not
fine since it isn't contained in the macro itself (that is, even though
it is only used directly in the macro).
In the process this makes the stability tracking much more precise,
e.g. previously `println!("{}", unstable())` got no warning, but now it
does. As such, this is a bug fix that may cause [breaking-change]s.
The attribute is definitely feature gated, since it explicitly allows
side-stepping the feature gating system.
---
This updates `thread_local!` macro to use the attribute, since it uses
unstable features internally (initialising a struct with unstable
fields).
