rust/src/test/run-pass/loop-label-shadowing.rs
Felix S. Klock II b445bf2bd1 make for PAT in ITER_EXPR { ... } a terminating-scope for ITER_EXPR.
In effect, temporary anonymous values created during the evaluation of
ITER_EXPR no longer not live for the entirety of the block surrounding
the for-loop; instead they only live for the extent of the for-loop
itself, and no longer.

----

There is one case I know of that this breaks, demonstrated to me by
niko (but it is also a corner-case that is useless in practice).  Here
is that case:

```
fn main() {
    let mut foo: Vec<&i8> = Vec::new();
    for i in &[1, 2, 3] { foo.push(i) }
}
```

Note that if you add any code following the for-loop above, or even a
semicolon to the end of it, then the code will stop compiling (i.e.,
it gathers a vector of references but the gathered vector cannot
actually be used.)

(The above code, despite being useless, did occur in one run-pass test
by accident; that test is updated here to accommodate the new
striction.)

----

So, technically this is a:

[breaking-change]
2015-02-06 00:07:37 +01:00

19 lines
590 B
Rust

// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Issue #12512.
fn main() {
let mut foo = Vec::new();
'foo: for i in &[1, 2, 3] {
foo.push(*i);
}
}