src/test/run-pass/borrowck-closures-two-imm.rs

   1 // Copyright 2014 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 // Tests that two closures can simultaneously have immutable
  12 // access to the variable, whether that immutable access be used
  13 // for direct reads or for taking immutable ref. Also check
  14 // that the main function can read the variable too while
  15 // the closures are in scope. Issue #6801.
  16
  17
  18 fn a() -> i32 {
  19     let mut x = 3;
  20     x += 1;
  21     let c1 = || x * 4;
  22     let c2 = || x * 5;
  23     c1() * c2() * x
  24 }
  25
  26 fn get(x: &i32) -> i32 {
  27     *x * 4
  28 }
  29
  30 fn b() -> i32 {
  31     let mut x = 3;
  32     x += 1;
  33     let c1 = || get(&x);
  34     let c2 = || get(&x);
  35     c1() * c2() * x
  36 }
  37
  38 fn c() -> i32 {
  39     let mut x = 3;
  40     x += 1;
  41     let c1 = || x * 5;
  42     let c2 = || get(&x);
  43     c1() * c2() * x
  44 }
  45
  46 pub fn main() {
  47     assert_eq!(a(), 1280);
  48     assert_eq!(b(), 1024);
  49     assert_eq!(c(), 1280);
  50 }