| #![feature(generators)] |
| #![feature(optin_builtin_traits)] |
| |
| auto trait Foo {} |
| |
| struct No; |
| |
| impl !Foo for No {} |
| |
| struct A<'a, 'b>(&'a mut bool, &'b mut bool, No); |
| |
| impl<'a, 'b: 'a> Foo for A<'a, 'b> {} |
| |
| struct OnlyFooIfStaticRef(No); |
| impl Foo for &'static OnlyFooIfStaticRef {} |
| |
| struct OnlyFooIfRef(No); |
| impl<'a> Foo for &'a OnlyFooIfRef {} |
| |
| fn assert_foo<T: Foo>(f: T) {} |
| |
| fn main() { |
| // Make sure 'static is erased for generator interiors so we can't match it in trait selection |
| let x: &'static _ = &OnlyFooIfStaticRef(No); |
| let gen = || { |
| let x = x; |
| yield; |
| assert_foo(x); |
| }; |
| assert_foo(gen); |
| //~^ ERROR implementation of `Foo` is not general enough |
| |
| // Allow impls which matches any lifetime |
| let x = &OnlyFooIfRef(No); |
| let gen = || { |
| let x = x; |
| yield; |
| assert_foo(x); |
| }; |
| assert_foo(gen); // ok |
| |
| // Disallow impls which relates lifetimes in the generator interior |
| let gen = || { |
| let a = A(&mut true, &mut true, No); |
| yield; |
| assert_foo(a); |
| }; |
| assert_foo(gen); |
| //~^ ERROR not general enough |
| } |