{"ast_node_type":"other","tokens":[{"end":42,"kind":"keyword","start":0,"text":"Ok(concrete_opaque_types)"}]}
            Ok(concrete_opaque_types) => {
        DefiningScopeKind::MirBorrowck => match tcx.mir_borrowck(owner_def_id) {
                if let Some(hidden_ty) = concrete_opaque_types.0.get(&def_id) {