src/test/compile-fail/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     // In fact there is no good reason for this to be an error, but
  38     // whatever, I'm mostly concerned it doesn't ICE right now:
  39     want_foo::<SomeStruct<usize>>();
  40     //~^ ERROR requirement `for<'a> usize : 'a` is not satisfied
  41 }
  42
  43 ///////////////////////////////////////////////////////////////////////////
  44 // Expressed as shorthand
  45
  46 struct AnotherStruct<X> {
  47     x: X
  48 }
  49
  50 impl<'a,X:'a> Foo<&'a isize> for AnotherStruct<X>
  51 {
  52 }
  53
  54 fn two() {
  55     want_foo::<AnotherStruct<usize>>();
  56     //~^ ERROR requirement `for<'a> usize : 'a` is not satisfied
  57 }
  58
  59 fn main() { }