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#![feature(specialization)] //~ WARN the feature `specialization` is incomplete
trait Foo: Copy + ToString {}
impl<T: Copy + ToString> Foo for T {}
fn hide<T: Foo>(x: T) -> impl Foo {
x
}
trait Leak: Sized {
type T;
fn leak(self) -> Self::T;
}
impl<T> Leak for T {
default type T = ();
default fn leak(self) -> Self::T { panic!() }
}
impl Leak for i32 {
type T = i32;
fn leak(self) -> i32 { self }
}
fn main() {
let _: u32 = hide(0_u32);
//~^ ERROR mismatched types
//~| expected type `u32`
//~| found opaque type `impl Foo`
//~| expected `u32`, found opaque type
let _: i32 = Leak::leak(hide(0_i32));
//~^ ERROR mismatched types
//~| expected type `i32`
//~| found associated type `<impl Foo as Leak>::T`
//~| expected `i32`, found associated type
let mut x = (hide(0_u32), hide(0_i32));
x = (x.1,
//~^ ERROR mismatched types
//~| expected `u32`, found `i32`
x.0);
//~^ ERROR mismatched types
//~| expected `i32`, found `u32`
}
|
