| // Copyright 2015 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. |
| |
| // Test that we mutate a counter on the stack only when we expect to. |
| |
| fn call<F>(f: F) where F : FnOnce() { |
| f(); |
| } |
| |
| fn main() { |
| let y = vec!(format!("Hello"), format!("World")); |
| let mut counter = 22_u32; |
| |
| call(|| { |
| // Move `y`, but do not move `counter`, even though it is read |
| // by value (note that it is also mutated). |
| for item in y { |
| let v = counter; |
| counter += v; |
| } |
| }); |
| assert_eq!(counter, 88); |
| |
| call(move || { |
| // this mutates a moved copy, and hence doesn't affect original |
| counter += 1; |
| }); |
| assert_eq!(counter, 88); |
| } |
