contract C { function f() public { (bool success,) = address(this).call(); require(success); (success,) = address(this).call(bytes4(0x12345678)); require(success); (success,) = address(this).call(uint(1)); require(success); (success,) = address(this).call(uint(1), uint(2)); require(success); } } // ---- // TypeError: (65-85): Wrong argument count for function call: 0 arguments given but expected 1. This function requires a single bytes argument. Use "" as argument to provide empty calldata. // TypeError: (153-171): Invalid type for argument in function call. Invalid implicit conversion from bytes4 to bytes memory requested. This function requires a single bytes argument. If all your arguments are value types, you can use abi.encode(...) to properly generate it. // TypeError: (240-247): Invalid type for argument in function call. Invalid implicit conversion from uint256 to bytes memory requested. This function requires a single bytes argument. If all your arguments are value types, you can use abi.encode(...) to properly generate it. // TypeError: (297-333): Wrong argument count for function call: 2 arguments given but expected 1. This function requires a single bytes argument. If all your arguments are value types, you can use abi.encode(...) to properly generate it.