{"ast_node_type":"other","tokens":[{"end":67,"kind":"keyword","start":0,"text":"//"}]}
            // FIXME: Could also check that the RPIT is not defined
        let (def_id, args) = match *expected_ty.kind() {
            ty::Alias(ty::Opaque, alias_ty) => (alias_ty.def_id.as_local()?, alias_ty.args),