src/test/run-pass/hrtb-type-outlives.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 // Test what happens when a HR obligation is applied to an impl with
  12 // "outlives" bounds. Currently we're pretty conservative here; this
  13 // will probably improve in time.
  14
  15 trait Foo<X> {
  16     fn foo(&self, x: X) { }
  17 }
  18
  19 fn want_foo<T>()
  20     where T : for<'a> Foo<&'a isize>
  21 {
  22 }
  23
  24 ///////////////////////////////////////////////////////////////////////////
  25 // Expressed as a where clause
  26
  27 struct SomeStruct<X> {
  28     x: X
  29 }
  30
  31 impl<'a,X> Foo<&'a isize> for SomeStruct<X>
  32     where X : 'a
  33 {
  34 }
  35
  36 fn one() {
  37     want_foo::<SomeStruct<usize>>();
  38 }
  39
  40 ///////////////////////////////////////////////////////////////////////////
  41 // Expressed as shorthand
  42
  43 struct AnotherStruct<X> {
  44     x: X
  45 }
  46
  47 impl<'a,X:'a> Foo<&'a isize> for AnotherStruct<X>
  48 {
  49 }
  50
  51 fn two() {
  52     want_foo::<AnotherStruct<usize>>();
  53 }
  54
  55 fn main() { }