src/test/ui/run-pass/borrowck/borrowck-freeze-frozen-mut.rs

   1 // Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // run-pass
  12 // Test that a `&mut` inside of an `&` is freezable.
  13
  14
  15 struct MutSlice<'a, T:'a> {
  16     data: &'a mut [T]
  17 }
  18
  19 fn get<'a, T>(ms: &'a MutSlice<'a, T>, index: usize) -> &'a T {
  20     &ms.data[index]
  21 }
  22
  23 pub fn main() {
  24     let mut data = [1, 2, 3];
  25     {
  26         let slice = MutSlice { data: &mut data };
  27         slice.data[0] += 4;
  28         let index0 = get(&slice, 0);
  29         let index1 = get(&slice, 1);
  30         let index2 = get(&slice, 2);
  31         assert_eq!(*index0, 5);
  32         assert_eq!(*index1, 2);
  33         assert_eq!(*index2, 3);
  34     }
  35     assert_eq!(data[0], 5);
  36     assert_eq!(data[1], 2);
  37     assert_eq!(data[2], 3);
  38 }