[rustc.git] / src / test / ui / typeck / typeck-default-trait-impl-precedence.rs

// Test that declaring that `&T` is `Defaulted` if `T:Signed` implies
// that other `&T` is NOT `Defaulted` if `T:Signed` does not hold. In
// other words, the auto impl only applies if there are no existing
// impls whose types unify.

#![feature(optin_builtin_traits)]
#![feature(negative_impls)]

auto trait Defaulted { }
impl<'a,T:Signed> Defaulted for &'a T { }
impl<'a,T:Signed> Defaulted for &'a mut T { }
fn is_defaulted<T:Defaulted>() { }

trait Signed { }
impl Signed for i32 { }

fn main() {
    is_defaulted::<&'static i32>();
    is_defaulted::<&'static u32>();
    //~^ ERROR `u32: Signed` is not satisfied
}
Commit	Line	Data
c34b1796 AL	1	// Test that declaring that `&T` is `Defaulted` if `T:Signed` implies
c34b1796 AL	2	// that other `&T` is NOT `Defaulted` if `T:Signed` does not hold. In
2c00a5a8	3	// other words, the auto impl only applies if there are no existing
c34b1796 AL	4	// impls whose types unify.
	5
	6	#![feature(optin_builtin_traits)]
ba9703b0	7	#![feature(negative_impls)]
c34b1796	8
2c00a5a8	9	auto trait Defaulted { }
c34b1796 AL	10	impl<'a,T:Signed> Defaulted for &'a T { }
	11	impl<'a,T:Signed> Defaulted for &'a mut T { }
	12	fn is_defaulted<T:Defaulted>() { }
	13
9346a6ac	14	trait Signed { }
c34b1796 AL	15	impl Signed for i32 { }
	16
	17	fn main() {
	18	is_defaulted::<&'static i32>();
	19	is_defaulted::<&'static u32>();
54a0048b	20	//~^ ERROR `u32: Signed` is not satisfied
c34b1796	21	}