is_trait = Some(ty::TraitRef::identity(tcx, def_id));
*generics
}
- ItemKind::OpaqueTy(OpaqueTy {
- origin: hir::OpaqueTyOrigin::AsyncFn(..) | hir::OpaqueTyOrigin::FnReturn(..),
- ..
- }) => {
- // return-position impl trait
- //
- // We don't inherit predicates from the parent here:
- // If we have, say `fn f<'a, T: 'a>() -> impl Sized {}`
- // then the return type is `f::<'static, T>::{{opaque}}`.
- //
- // If we inherited the predicates of `f` then we would
- // require that `T: 'static` to show that the return
- // type is well-formed.
- //
- // The only way to have something with this opaque type
- // is from the return type of the containing function,
- // which will ensure that the function's predicates
- // hold.
- return ty::GenericPredicates { parent: None, predicates: &[] };
- }
ItemKind::OpaqueTy(OpaqueTy {
ref generics,
origin: hir::OpaqueTyOrigin::TyAlias,