This is not technically a [breaking-change], but it will be soon, so
you should update your code. Typically, shadowing is accidental, and
the shadowing lifetime can simply be removed. This frequently occurs
in constructor patterns:
```rust
// Old:
impl<'a> SomeStruct<'a> { fn new<'a>(..) -> SomeStruct<'a> { ... } }
// Should be:
impl<'a> SomeStruct<'a> { fn new(..) -> SomeStruct<'a> { ... } }
```
Otherwise, you should rename the inner lifetime to something
else. Note though that lifetime elision frequently applies:
```rust
// Old
impl<'a> SomeStruct<'a> {
fn get<'a>(x: &'a self) -> &'a T { &self.field }
}
// Should be:
impl<'a> SomeStruct<'a> {
fn get(x: &self) -> &T { &self.field }
}
``
They are replaced with unboxed closures.
cc @pcwalton @aturon
This is a [breaking-change]. Mostly, uses of `proc()` simply need to be converted to `move||` (unboxed closures), but in some cases the adaptations required are more complex (particularly for library authors). A detailed write-up can be found here: http://smallcultfollowing.com/babysteps/blog/2014/11/26/purging-proc/
The commits are ordered to emphasize the more important changes, but are not truly standalone.
Unlike a tuple variant constructor which can be called as a function, a struct variant constructor is not a function, so cannot be called.
If the user tries to assign the constructor to a variable, an ICE occurs, because there is no way to use it later. So we should stop the constructor from being used like that.
A similar mechanism already exists for a normal struct, as it prohibits a struct from being resolved. This commit does the same for a struct variant.
This commit also includes some changes to the existing tests.
Fixes#19452.
in most cases, just the error message changed, but in some cases we
are reporting new errors that OUGHT to have been reported before but
we're overlooked (mostly involving the `'static` bound on `Send`).
The current behavior leads to adjustments like `&&*` being applied
instead of just `&` (when the unmodified receiver is a `&T` or an `&mut
T`). This causes both safety errors and unexpected behavior. The safety
errors result from regionck not being prepared for auto-ref-ref-like
adjustments; this is worth fixing on its own, but I think the best way
to do it is to modify regionck to use expr-use-visitor (and fix
expr-use-visitor as well, which I don't think properly invokes `borrow`
for each level of auto-ref), and for now it's simpler to just not
produce the adjustment in question. (I have a separate patch porting
regionck to use exprusevisitor for a different bug, so that is coming.)
Previously, the DeBruijn index for the self type was not being
adjusted to account for the fn binder. This mean that when late-bound
regions were instantiated, you sometimes wind up with two distinct
lifetimes.
Fixes#19537.
Unlike a tuple variant constructor which can be called as a function, a
struct variant constructor is not a function, so cannot be called.
If the user tries to assign the constructor to a variable, an ICE
occurs, because there is no way to use it later. So we should stop the
constructor from being used like that.
A similar mechanism already exists for a normal struct, as it prohibits
a struct from being resolved. This commit does the same for a struct
variant.
This commit also includes some changes to the existing tests.
Fixes#19452.
When a type error occurs, check_method_argument_types() tries to provide
arguments filled with ty::mk_err(). However, if a function takes the
parameters as a tuple, the arguments should be converted to a tuple
before being passed to check_argument_types().
Fixes#19521.
This means that `Fn(&A) -> (&B, &C)` is equivalent to `for<'a> Fn(&'a A)
-> (&'a B, &'a C)` similar to the lifetime elision of lower-case `fn` in
types and declarations.
Closes#18992.
detect UFCS drop and allow UFCS methods to have explicit type parameters.
Work towards #18875.
Since code could previously call the methods & implement the traits
manually, this is a
[breaking-change]
Closes#19586. Closes#19375.
This is particularly important for deeply nested types, which generate deeply nested impls. This is a fix for #19318. It's possible we could also improve this particular case not to increment the recursion count, but it's worth being able to adjust the recursion limit anyhow.
cc @jdm
r? @pcwalton
This change makes the compiler no longer infer whether types (structures
and enumerations) implement the `Copy` trait (and thus are implicitly
copyable). Rather, you must implement `Copy` yourself via `impl Copy for
MyType {}`.
A new warning has been added, `missing_copy_implementations`, to warn
you if a non-generic public type has been added that could have
implemented `Copy` but didn't.
For convenience, you may *temporarily* opt out of this behavior by using
`#![feature(opt_out_copy)]`. Note though that this feature gate will never be
accepted and will be removed by the time that 1.0 is released, so you should
transition your code away from using it.
This breaks code like:
#[deriving(Show)]
struct Point2D {
x: int,
y: int,
}
fn main() {
let mypoint = Point2D {
x: 1,
y: 1,
};
let otherpoint = mypoint;
println!("{}{}", mypoint, otherpoint);
}
Change this code to:
#[deriving(Show)]
struct Point2D {
x: int,
y: int,
}
impl Copy for Point2D {}
fn main() {
let mypoint = Point2D {
x: 1,
y: 1,
};
let otherpoint = mypoint;
println!("{}{}", mypoint, otherpoint);
}
This is the backwards-incompatible part of #13231.
Part of RFC #3.
[breaking-change]
Closes#18959
Technically, this causes code that once compiled to no longer compile, but
that code probably never ran.
[breaking-change]
------------
Not quite sure the error message is good enough, I feel like it ought to tell you "because it inherits from non-object-safe trait Foo", so I've opened up a follow-up issue #19538
This means that `Fn(&A) -> (&B, &C)` is equivalent to `for<'a> Fn(&'a A)
-> (&'a B, &'a C)` similar to the lifetime elision of lower-case `fn` in
types and declarations.
Closes#18992.
detect UFCS drop and allow UFCS methods to have explicit type parameters.
Work towards #18875.
Since code could previously call the methods & implement the traits
manually, this is a
[breaking-change]
Closes#19586. Closes#19375.
In regards to:
https://github.com/rust-lang/rust/issues/19253#issuecomment-64836729
This commit:
* Changes the #deriving code so that it generates code that utilizes fewer
reexports (in particur Option::* and Result::*), which is necessary to
remove those reexports in the future
* Changes other areas of the codebase so that fewer reexports are utilized
As an example of what this changes, the following code:
```rust
let x: [int ..4];
```
Currently spits out ‘expected `]`, found `..`’. However, a comma would also be valid there, as would a number of other tokens. This change adjusts the parser to produce more accurate errors, so that that example now produces ‘expected one of `(`, `+`, `,`, `::`, or `]`, found `..`’.
(Thanks to cramer on IRC for pointing out this problem with diagnostics.)
io::stdin returns a new `BufferedReader` each time it's called, which
results in some very confusing behavior with disappearing output. It now
returns a `StdinReader`, which wraps a global singleton
`Arc<Mutex<BufferedReader<StdReader>>`. `Reader` is implemented directly
on `StdinReader`. However, `Buffer` is not, as the `fill_buf` method is
fundamentaly un-thread safe. A `lock` method is defined on `StdinReader`
which returns a smart pointer wrapping the underlying `BufferedReader`
while guaranteeing mutual exclusion.
Code that treats the return value of io::stdin as implementing `Buffer`
will break. Add a call to `lock`:
```rust
io::stdin().read_line();
// =>
io::stdin().lock().read_line();
```
Closes#14434
[breaking-change]
The only other place I know of that doesn’t allow trailing commas is closure types (#19414), and those are a bit tricky to fix (I suspect it might be impossible without infinite lookahead) so I didn’t implement that in this patch. There are other issues surrounding closure type parsing anyway, in particular #19410.
This has the goal of further reducing peak memory usage and enabling more parallelism. This patch should allow trans/typeck to build in parallel. The plan is to proceed by moving as many additional passes as possible into distinct crates that lay alongside typeck/trans. Basically, the idea is that there is the `rustc` crate which defines the common data structures shared between passes. Individual passes then go into their own crates. Finally, the `rustc_driver` crate knits it all together.
cc @jakub-: One wrinkle is the diagnostics plugin. Currently, it assumes all diagnostics are defined and used within one crate in order to track what is used and what is duplicated. I had to disable this. We'll have to find an alternate strategy, but I wasn't sure what was best so decided to just disable the duplicate checking for now.
On *BSD systems, we can `open(2)` a directory and directly `read(2)` from it due to an old tradition. We should avoid doing so by explicitly calling `fstat(2)` to check the type of the opened file.
Opening a directory as a module file can't always be avoided. Even when there's no "path" attribute trick involved, there can always be a *directory* named `my_module.rs`.
Incidentally, remove unnecessary mutability of `&self` from `io::fs::File::stat()`.
