[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 'unconstrained opaque type' error

#![feature(type_alias_impl_trait)]

mod foo {
    pub type Foo = impl Copy;
    //~^ ERROR unconstrained opaque type

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

fn main() {
    let _: foo::Foo = std::mem::transmute(0u8);
    //~^ ERROR cannot transmute between types of different sizes, or dependently-sized types
}
Commit	Line	Data
416331ca	1	// Issue 52985: user code provides no use case that allows a type alias `impl Trait`
5e7ed085	2	// We now emit a 'unconstrained opaque type' error
416331ca	3
94222f64	4	#![feature(type_alias_impl_trait)]
416331ca	5
923072b8 FG	6	mod foo {
	7	pub type Foo = impl Copy;
	8	//~^ ERROR unconstrained opaque type
416331ca	9
923072b8 FG	10	// make compiler happy about using 'Foo'
	11	pub fn bar(x: Foo) -> Foo {
	12	x
	13	}
136023e0	14	}
416331ca XL	15
416331ca XL	16	fn main() {
923072b8 FG	17	let _: foo::Foo = std::mem::transmute(0u8);
923072b8 FG	18	//~^ ERROR cannot transmute between types of different sizes, or dependently-sized types
416331ca	19	}