src/test/compile-fail/fn-variance-1.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 fn takes_imm(x: &isize) { }
  12
  13 fn takes_mut(x: &mut isize) { }
  14
  15 fn apply<T, F>(t: T, f: F) where F: FnOnce(T) {
  16     f(t)
  17 }
  18
  19 fn main() {
  20     apply(&3, takes_imm);
  21     apply(&3, takes_mut);
  22     //~^ ERROR (types differ in mutability)
  23
  24     apply(&mut 3, takes_mut);
  25     apply(&mut 3, takes_imm);
  26     //~^ ERROR (types differ in mutability)
  27 }