hyperledger-solang_solang/tests/contract_testcases/substrate/libraries/using_03.sol

        library x {
            function max(uint64 a, uint64 b) private pure returns (uint64) {
                return a > b ? a : b;
            }
        }

        contract c {
            using x for x;
        }
// ---- Expect: diagnostics ----
// error: 9:25-26: using for library 'x' type not permitted