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// `Opaque<'?1> := u8` is not a valid defining use here.
//
// Due to fundamental limitations of the member constraints algorithm,
// we require '?1 to be *equal* to some universal region.
//
// While '?1 is eventually inferred to be equal to 'x because of the constraint '?1: 'x,
// we don't consider them equal in the strict sense because they lack the bidirectional outlives
// constraints ['?1: 'x, 'x: '?1]. In NLL terms, they are not part of the same SCC.
//
// See #113971 for details.
//@ revisions: basic member_constraints
#![feature(type_alias_impl_trait)]
trait Captures<'a> {}
impl<T> Captures<'_> for T {}
fn ensure_outlives<'a, X: 'a>(_: X) {}
fn relate<X>(_: X, _: X) {}
type Opaque<'a> = impl Copy + Captures<'a>;
#[define_opaque(Opaque)]
fn test<'x>(_: Opaque<'x>) {
let opaque = None::<Opaque<'_>>; // let's call this lifetime '?1
#[cfg(basic)]
let hidden = None::<u8>;
#[cfg(member_constraints)]
let hidden = None::<&'x u8>;
ensure_outlives::<'x>(opaque); // outlives constraint: '?1: 'x
relate(opaque, hidden); // defining use: Opaque<'?1> := u8
//~^ ERROR expected generic lifetime parameter, found `'_`
}
fn main() {}
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