bors [Tue, 24 Mar 2015 22:44:33 +0000 (22:44 +0000)]
Auto merge of #23546 - alexcrichton:hyphens, r=brson
The compiler will now issue a warning for crates that have syntax of the form
`extern crate "foo" as bar`, but it will still continue to accept this syntax.
Additionally, the string `foo-bar` will match the crate name `foo_bar` to assist
in the transition period as well.
This patch will land hopefully in tandem with a Cargo patch that will start
translating all crate names to have underscores instead of hyphens.
Alex Crichton [Tue, 24 Mar 2015 22:27:14 +0000 (15:27 -0700)]
rollup merge of #23638: pnkfelix/fsk-reject-specialized-drops
Reject specialized Drop impls.
See Issue #8142 for discussion.
This makes it illegal for a Drop impl to be more specialized than the original item.
So for example, all of the following are now rejected (when they would have been blindly accepted before):
```rust
struct S<A> { ... };
impl Drop for S<i8> { ... } // error: specialized to concrete type
struct T<'a> { ... };
impl Drop for T<'static> { ... } // error: specialized to concrete region
struct U<A> { ... };
impl<A:Clone> Drop for U<A> { ... } // error: added extra type requirement
struct V<'a,'b>;
impl<'a,'b:a> Drop for V<'a,'b> { ... } // error: added extra region requirement
```
Due to examples like the above, this is a [breaking-change].
(The fix is to either remove the specialization from the `Drop` impl, or to transcribe the requirements into the struct/enum definition; examples of both are shown in the PR's fixed to `libstd`.)
----
This is likely to be the last thing blocking the removal of the `#[unsafe_destructor]` attribute.
Alex Crichton [Tue, 24 Mar 2015 21:56:00 +0000 (14:56 -0700)]
rollup merge of #23546: alexcrichton/hyphens
The compiler will now issue a warning for crates that have syntax of the form
`extern crate "foo" as bar`, but it will still continue to accept this syntax.
Additionally, the string `foo-bar` will match the crate name `foo_bar` to assist
in the transition period as well.
This patch will land hopefully in tandem with a Cargo patch that will start
translating all crate names to have underscores instead of hyphens.
Alex Crichton [Thu, 19 Mar 2015 22:39:03 +0000 (15:39 -0700)]
rustc: Add support for `extern crate foo as bar`
The compiler will now issue a warning for crates that have syntax of the form
`extern crate "foo" as bar`, but it will still continue to accept this syntax.
Additionally, the string `foo-bar` will match the crate name `foo_bar` to assist
in the transition period as well.
This patch will land hopefully in tandem with a Cargo patch that will start
translating all crate names to have underscores instead of hyphens.
Alex Crichton [Tue, 24 Mar 2015 21:50:48 +0000 (14:50 -0700)]
rollup merge of #23668: alexcrichton/io-zero
This commit alters the behavior of the `Read::read_to_end()` method to zero all
memory instead of passing an uninitialized buffer to `read`. This change is
motivated by the [discussion on the internals forum][discuss] where the
conclusion has been that the standard library will not expose uninitialized
memory.
Alex Crichton [Tue, 24 Mar 2015 21:50:45 +0000 (14:50 -0700)]
rollup merge of #23592: alexcrichton/tweak-at-exit
There have been some recent panics on the bots and this commit is an attempt to
appease them. Previously it was considered invalid to run `rt::at_exit` after
the handlers had already started running. Due to the multithreaded nature of
applications, however, it is not always possible to guarantee this. For example
[this program][ex] will show off the abort.
The semantics of the `rt::at_exit` function have been modified as such:
* It is now legal to call `rt::at_exit` at any time. The return value now
indicates whether the closure was successfully registered or not. Callers must
now decide what to do with this information.
* The `rt::at_exit` handlers will now be run for a fixed number of iterations.
Common cases (such as the example shown) may end up registering a new handler
while others are running perhaps once or twice, so this common condition is
covered by re-running the handlers a fixed number of times, after which new
registrations are forbidden.
Some usage of `rt::at_exit` was updated to handle these new semantics, but
deprecated or unstable libraries calling `rt::at_exit` were not updated.
Alex Crichton [Tue, 24 Mar 2015 21:50:44 +0000 (14:50 -0700)]
rollup merge of #23282: nikomatsakis/fn-trait-inheritance
The primary motivation here is to sidestep #19032 -- for a time, I thought that we should improve coherence or otherwise extend the language, but I now think that any such changes will require more time to bake. In the meantime, inheritance amongst the fn traits is both logically correct *and* a simple solution to that obstacle. This change introduces inheritance and modifies the compiler so that it can properly generate impls for closures and fns.
Things enabled by this PR (but not included in this PR):
1. An impl of `FnMut` for `&mut F` where `F : FnMut` (https://github.com/rust-lang/rust/issues/23015).
2. A better version of `Thunk` I've been calling `FnBox`.
I did not include either of these in the PR because:
1. Adding the impls in 1 currently induces a coherence conflict with the pattern trait. This is interesting and merits some discussion.
2. `FnBox` deserves to be a PR of its own.
The main downside to this design is (a) the need to write impls by hand; (b) the possibility of implementing `FnMut` with different semantics from `Fn`, etc. Point (a) is minor -- in particular, it does not affect normal closure usage -- and could be addressed in the future in many ways (better defaults; convenient macros; specialization; etc). Point (b) is unfortunate but "just a bug" from my POV, and certainly not unique to these traits (c.f. Copy/Clone, PartialEq/Eq, etc). (Until we lift the feature-gate on implementing the Fn traits, in any case, there is room to correct both of these if we find a nice way.)
Note that I believe this change is reversible in the future if we decide on another course of action, due to the feature gate on implementing the `Fn` traits, though I do not (currently) think we should reverse it.
This makes it illegal for a Drop impl to be more specialized than the
original item.
So for example, all of the following are now rejected (when they would
have been blindly accepted before):
```rust
struct S<A> { ... };
impl Drop for S<i8> { ... } // error: specialized to concrete type
struct T<'a> { ... };
impl Drop for T<'static> { ... } // error: specialized to concrete region
struct U<A> { ... };
impl<A:Clone> Drop for U<A> { ... } // error: added extra type requirement
struct V<'a,'b>;
impl<'a,'b:a> Drop for V<'a,'b> { ... } // error: added extra region requirement
```
Due to examples like the above, this is a [breaking-change].
(The fix is to either remove the specialization from the `Drop` impl,
or to transcribe the requirements into the struct/enum definition;
examples of both are shown in the PR's fixed to `libstd`.)
----
This is likely to be the last thing blocking the removal of the
`#[unsafe_destructor]` attribute.
Includes two new error codes for the new dropck check.
Update run-pass tests to accommodate new dropck pass.
Update tests and docs to reflect new destructor restriction.
----
Implementation notes:
We identify Drop impl specialization by not being as parametric as the
struct/enum definition via unification.
More specifically:
1. Attempt unification of a skolemized instance of the struct/enum
with an instance of the Drop impl's type expression where all of
the impl's generics (i.e. the free variables of the type
expression) have been replaced with unification variables.
2. If unification fails, then reject Drop impl as specialized.
3. If unification succeeds, check if any of the skolemized
variables "leaked" into the constraint set for the inference
context; if so, then reject Drop impl as specialized.
4. Otherwise, unification succeeded without leaking skolemized
variables: accept the Drop impl.
We identify whether a Drop impl is injecting new predicates by simply
looking whether the predicate, after an appropriate substitution,
appears on the struct/enum definition.
Nick Cameron [Fri, 20 Mar 2015 04:15:27 +0000 (17:15 +1300)]
Add trivial cast lints.
This permits all coercions to be performed in casts, but adds lints to warn in those cases.
Part of this patch moves cast checking to a later stage of type checking. We acquire obligations to check casts as part of type checking where we previously checked them. Once we have type checked a function or module, then we check any cast obligations which have been acquired. That means we have more type information available to check casts (this was crucial to making coercions work properly in place of some casts), but it means that casts cannot feed input into type inference.
[breaking change]
* Adds two new lints for trivial casts and trivial numeric casts, these are warn by default, but can cause errors if you build with warnings as errors. Previously, trivial numeric casts and casts to trait objects were allowed.
* The unused casts lint has gone.
* Interactions between casting and type inference have changed in subtle ways. Two ways this might manifest are:
- You may need to 'direct' casts more with extra type information, for example, in some cases where `foo as _ as T` succeeded, you may now need to specify the type for `_`
- Casts do not influence inference of integer types. E.g., the following used to type check:
```
let x = 42;
let y = &x as *const u32;
```
Because the cast would inform inference that `x` must have type `u32`. This no longer applies and the compiler will fallback to `i32` for `x` and thus there will be a type error in the cast. The solution is to add more type information:
```
let x: u32 = 42;
let y = &x as *const u32;
```
Alex Crichton [Tue, 24 Mar 2015 18:14:35 +0000 (11:14 -0700)]
std: Zero memory when calling `read_to_end()`
This commit alters the behavior of the `Read::read_to_end()` method to zero all
memory instead of passing an uninitialized buffer to `read`. This change is
motivated by the [discussion on the internals forum][discuss] where the
conclusion has been that the standard library will not expose uninitialized
memory.
Alex Crichton [Tue, 24 Mar 2015 00:13:39 +0000 (17:13 -0700)]
rollup merge of #23653: dhuseby/bitrig-stage0-c64d671
@alexcrichton this adds the latest Bitrig snapshot. Please upload the corresponding snapshot: https://github.com/dhuseby/rust-cross-bitrig/blob/master/snapshots/rust-stage0-2015-03-17-c64d671-bitrig-x86_64-41de2c7a69a1ac648d3fa3b65e96a29bdc122163.tar.bz2
Alex Crichton [Tue, 24 Mar 2015 00:13:38 +0000 (17:13 -0700)]
rollup merge of #23652: alexcrichton/stabilize-hasher-finish
This commit enables writing a stable implementation of the `Hasher` trait as
well as actually calculating the hash of a vlaue in a stable fashion. The
signature is stabilized as-is.
Alex Crichton [Tue, 24 Mar 2015 00:13:27 +0000 (17:13 -0700)]
rollup merge of #23509: aturon/stab-entry
This commit marks as `#[stable]` the `Entry` types for the maps provided
by `std`. The main reason these had been left unstable previously was
uncertainty about an eventual trait design, but several plausible
designs have been proposed that all work fine with the current type definitions.
Niko Matsakis [Wed, 11 Mar 2015 14:08:33 +0000 (10:08 -0400)]
Fallout from changing fn traits to use inheritance rather than bridge
impls. This is a [breaking-change] (for gated code) in that when you
implement `Fn` (`FnMut`) you must also implement `FnOnce`. This commit
demonstrates how to fix it.
Aaron Turon [Thu, 19 Mar 2015 06:36:19 +0000 (23:36 -0700)]
Stabilize Entry types
This commit marks as `#[stable]` the `Entry` types for the maps provided
by `std`. The main reason these had been left unstable previously was
uncertainty about an eventual trait design, but several plausible
designs have been proposed that all work fine with the current type definitions.
Alex Crichton [Mon, 23 Mar 2015 22:26:24 +0000 (15:26 -0700)]
rollup merge of #23503: alexcrichton/fix-ptr-docs
The method with which backwards compatibility was retained ended up leading to
documentation that rustdoc didn't handle well and largely ended up confusing.
Alex Crichton [Mon, 23 Mar 2015 22:26:24 +0000 (15:26 -0700)]
rollup merge of #23484: alexcrichton/marker-trait-stable
This trait has proven quite useful when defining marker traits to avoid the
semi-confusing `PhantomFn` trait and it looks like it will continue to be a
useful tool for defining these traits.
Alex Crichton [Mon, 23 Mar 2015 22:11:06 +0000 (15:11 -0700)]
rollup merge of #23633: tomjakubowski/rustdoc-array-prim
Previously, impls for `[T; n]` were collected in the same place as impls for `[T]` and `&[T]`. This splits them out into their own primitive page in both core and std.
Alex Crichton [Mon, 23 Mar 2015 22:10:57 +0000 (15:10 -0700)]
rollup merge of #23612: dotdash/closure_bloat
For the rust-call ABI, the last function argument is a tuple that gets
untupled for the actual call. For bare functions using this ABI, the
code has access to the tuple, so we need to tuple the arguments again.
But closures can't actually access the tuple. Their arguments map to the
elements in the tuple. So what we currently do is to tuple the arguments
and then immediately untuple them again, which is pretty useless and we
can just omit it.
Alex Crichton [Mon, 23 Mar 2015 22:10:50 +0000 (15:10 -0700)]
rollup merge of #23601: nikomatsakis/by-value-index
This is a [breaking-change]. When indexing a generic map (hashmap, etc) using the `[]` operator, it is now necessary to borrow explicitly, so change `map[key]` to `map[&key]` (consistent with the `get` routine). However, indexing of string-valued maps with constant strings can now be written `map["abc"]`.
Alex Crichton [Mon, 23 Mar 2015 22:09:09 +0000 (15:09 -0700)]
rollup merge of #23557: aturon/rfc-909
This commit implements [RFC 909](https://github.com/rust-lang/rfcs/pull/909):
The `std::thread_local` module is now deprecated, and its contents are
available directly in `std::thread` as `LocalKey`, `LocalKeyState`, and
`ScopedKey`.
The macros remain exactly as they were, which means little if any code
should break. Nevertheless, this is technically a:
Alex Crichton [Mon, 23 Mar 2015 22:09:08 +0000 (15:09 -0700)]
rollup merge of #23541: aturon/stab-error
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.
Alex Crichton [Mon, 23 Mar 2015 22:07:33 +0000 (15:07 -0700)]
rollup merge of #23283: brson/rpathfix
Fix regression in -C rpath that causes failures with symlinks
The new `relative_from` method no longer supports the case on unix
where both paths are absolute, which `-C rpath` depended on. This
version fixes the problem by copying the old path_relative_from
function into the rpath module.
Fixes #23140
After experimenting with the new `relative_from` function on `Path` I'm not sure what it's use case is. It no longer even figures out that the relative path from `/foo/bar` to `/foo/baz/qux` is `../baz/qux`.