src/test/ui/rfc-2632-const-trait-impl/const-trait-bound-opt-out/with-maybe-sized.rs

#![feature(const_trait_bound_opt_out)]
#![allow(incomplete_features)]

struct S<T: ?const ?Sized>(std::marker::PhantomData<T>);
//~^ ERROR `?const` and `?` are mutually exclusive
//~| ERROR `?const` on trait bounds is not yet implemented

fn main() {}