src/test/compile-fail/borrowck-assign-comp-idx.rs

   1 // Copyright 2012 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 struct Point {
  12     x: isize,
  13     y: isize,
  14 }
  15
  16 fn a() {
  17     let mut p = vec!(1);
  18
  19     // Create an immutable pointer into p's contents:
  20     let q: &isize = &p[0];
  21
  22     p[0] = 5; //~ ERROR cannot borrow
  23
  24     println!("{}", *q);
  25 }
  26
  27 fn borrow<F>(_x: &[isize], _f: F) where F: FnOnce() {}
  28
  29 fn b() {
  30     // here we alias the mutable vector into an imm slice and try to
  31     // modify the original:
  32
  33     let mut p = vec!(1);
  34
  35     borrow(
  36         &p,
  37         || p[0] = 5); //~ ERROR cannot borrow `p` as mutable
  38 }
  39
  40 fn c() {
  41     // Legal because the scope of the borrow does not include the
  42     // modification:
  43     let mut p = vec!(1);
  44     borrow(&p, ||{});
  45     p[0] = 5;
  46 }
  47
  48 fn main() {
  49 }