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// check-pass
// known-bug: #97156
#![feature(const_type_id, generic_const_exprs)]
#![allow(incomplete_features)]
use std::any::TypeId;
// `One` and `Two` are currently considered equal types, as both
// `One <: Two` and `One :> Two` holds.
type One = for<'a> fn(&'a (), &'a ());
type Two = for<'a, 'b> fn(&'a (), &'b ());
trait AssocCt {
const ASSOC: usize;
}
const fn to_usize<T: 'static>() -> usize {
const WHAT_A_TYPE: TypeId = TypeId::of::<One>();
match TypeId::of::<T>() {
WHAT_A_TYPE => 0,
_ => 1000,
}
}
impl<T: 'static> AssocCt for T {
const ASSOC: usize = to_usize::<T>();
}
trait WithAssoc<U> {
type Assoc;
}
impl<T: 'static> WithAssoc<()> for T where [(); <T as AssocCt>::ASSOC]: {
type Assoc = [u8; <T as AssocCt>::ASSOC];
}
fn generic<T: 'static, U>(x: <T as WithAssoc<U>>::Assoc) -> <T as WithAssoc<U>>::Assoc
where
[(); <T as AssocCt>::ASSOC]:,
T: WithAssoc<U>,
{
x
}
fn unsound<T>(x: <One as WithAssoc<T>>::Assoc) -> <Two as WithAssoc<T>>::Assoc
where
One: WithAssoc<T>,
{
let x: <Two as WithAssoc<T>>::Assoc = generic::<One, T>(x);
x
}
fn main() {
println!("{:?}", unsound::<()>([]));
}
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