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]
The test harness will make sure that the panic message contains the
specified string. This is useful to help make `#[should_fail]` tests a
bit less brittle by decreasing the chance that the test isn't
"accidentally" passing due to a panic occurring earlier than expected.
The behavior is in some ways similar to JUnit's `expected` feature:
`@Test(expected=NullPointerException.class)`.
Without the message assertion, this test would pass even though it's not
actually reaching the intended part of the code:
```rust
#[test]
#[should_fail(message = "out of bounds")]
fn test_oob_array_access() {
let idx: uint = from_str("13o").unwrap(); // oops, this will panic
[1i32, 2, 3][idx];
}
```
Now that we have an overloaded comparison (`==`) operator, and that `Vec`/`String` deref to `[T]`/`str` on method calls, many `as_slice()`/`as_mut_slice()`/`to_string()` calls have become redundant. This patch removes them. These were the most common patterns:
- `assert_eq(test_output.as_slice(), "ground truth")` -> `assert_eq(test_output, "ground truth")`
- `assert_eq(test_output, "ground truth".to_string())` -> `assert_eq(test_output, "ground truth")`
- `vec.as_mut_slice().sort()` -> `vec.sort()`
- `vec.as_slice().slice(from, to)` -> `vec.slice(from_to)`
---
Note that e.g. `a_string.push_str(b_string.as_slice())` has been left untouched in this PR, since we first need to settle down whether we want to favor the `&*b_string` or the `b_string[]` notation.
This is rebased on top of #19167
cc @alexcrichton @aturon
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::\*, Result::\*, and Ordering::\*), which is necessary to
remove those reexports in the future
* Changes other areas of the codebase so that fewer reexports are utilized
The test harness will make sure that the panic message contains the
specified string. This is useful to help make `#[should_fail]` tests a
bit less brittle by decreasing the chance that the test isn't
"accidentally" passing due to a panic occurring earlier than expected.
The behavior is in some ways similar to JUnit's `expected` feature:
`@Test(expected=NullPointerException.class)`.
Without the message assertion, this test would pass even though it's not
actually reaching the intended part of the code:
```rust
#[test]
#[should_fail(message = "out of bounds")]
fn test_oob_array_access() {
let idx: uint = from_str("13o").unwrap(); // oops, this will panic
[1i32, 2, 3][idx];
}
```
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.)
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.
As an example of what this changes, the following code:
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 `..`’.
