src/test/ui/extern/extern-types-trait-impl.rs

   1 // run-pass
   2 #![allow(dead_code)]
   3 // Test that traits can be implemented for extern types.
   4 #![feature(extern_types)]
   5
   6 extern "C" {
   7     type A;
   8 }
   9
  10 trait Foo {
  11     fn foo(&self) {}
  12 }
  13
  14 impl Foo for A {
  15     fn foo(&self) {}
  16 }
  17
  18 fn assert_foo<T: ?Sized + Foo>() {}
  19
  20 fn use_foo<T: ?Sized + Foo>(x: &dyn Foo) {
  21     x.foo();
  22 }
  23
  24 fn main() {
  25     assert_foo::<A>();
  26 }