[rustc.git] / src / test / ui / type-alias-impl-trait / no_inferrable_concrete_type.rs

// Issue 52985: user code provides no use case that allows a type alias `impl Trait`
// We now emit a 'could not find defining uses' error

// revisions: min_tait full_tait
#![feature(min_type_alias_impl_trait)]
#![cfg_attr(full_tait, feature(type_alias_impl_trait, impl_trait_in_bindings))]
//[full_tait]~^ WARN incomplete
//[full_tait]~| WARN incomplete

type Foo = impl Copy; //~ could not find defining uses

// make compiler happy about using 'Foo'
fn bar(x: Foo) -> Foo { x }

fn main() {
    let _: Foo = std::mem::transmute(0u8); //[min_tait]~ ERROR not permitted here
}
Commit	Line	Data
416331ca XL	1	// Issue 52985: user code provides no use case that allows a type alias `impl Trait`
	2	// We now emit a 'could not find defining uses' error
	3
6a06907d XL	4	// revisions: min_tait full_tait
	5	#![feature(min_type_alias_impl_trait)]
	6	#![cfg_attr(full_tait, feature(type_alias_impl_trait, impl_trait_in_bindings))]
	7	//[full_tait]~^ WARN incomplete
	8	//[full_tait]~\| WARN incomplete
416331ca XL	9
	10	type Foo = impl Copy; //~ could not find defining uses
	11
	12	// make compiler happy about using 'Foo'
	13	fn bar(x: Foo) -> Foo { x }
	14
	15	fn main() {
6a06907d	16	let _: Foo = std::mem::transmute(0u8); //[min_tait]~ ERROR not permitted here
416331ca	17	}