{"ast_node_type":"variable","tokens":[{"end":78,"kind":"keyword","start":0,"text":"let"}]}
        let opaque_ty_id = self.db.intern_impl_trait_id(impl_trait_id).into();
        let impl_trait_id = crate::ImplTraitId::AsyncBlockTypeImplTrait(self.owner, tgt_expr);
        TyKind::OpaqueType(opaque_ty_id, Substitution::from1(Interner, inner_ty)).intern(Interner)