src/test/run-pass/where-for-self.rs

   1 // Copyright 2015 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 // Test that we can quantify lifetimes outside a constraint (i.e., including
  12 // the self type) in a where clause.
  13
  14
  15 static mut COUNT: u32 = 1;
  16
  17 trait Bar<'a> {
  18     fn bar(&self);
  19 }
  20
  21 trait Baz<'a>
  22 {
  23     fn baz(&self);
  24 }
  25
  26 impl<'a, 'b> Bar<'b> for &'a u32 {
  27     fn bar(&self) {
  28         unsafe { COUNT *= 2; }
  29     }
  30 }
  31
  32 impl<'a, 'b> Baz<'b> for &'a u32 {
  33     fn baz(&self) {
  34         unsafe { COUNT *= 3; }
  35     }
  36 }
  37
  38 // Test we can use the syntax for HRL including the self type.
  39 fn foo1<T>(x: &T)
  40     where for<'a, 'b> &'a T: Bar<'b>
  41 {
  42     x.bar()
  43 }
  44
  45 // Test we can quantify multiple bounds (i.e., the precedence is sensible).
  46 fn foo2<T>(x: &T)
  47     where for<'a, 'b> &'a T: Bar<'b> + Baz<'b>
  48 {
  49     x.baz();
  50     x.bar()
  51 }
  52
  53 fn main() {
  54     let x = 42;
  55     foo1(&x);
  56     foo2(&x);
  57     unsafe {
  58         assert!(COUNT == 12);
  59     }
  60 }