qiskit/qasm/qasmparser.py
def p_gate_op_1(self, program):
        """
        gate_op : CX id ',' id ';'
        """
        program[0] = node.Cnot([program[2], program[4]])
        self.verify_declared_bit(program[2])
        self.verify_declared_bit(program[4])
        self.verify_distinct([program[2], program[4]])
def p_gate_op_1(self, program):
        """
        gate_op : CX id ',' id ';'
        """
        program[0] = node.Cnot([program[2], program[4]])
        self.verify_declared_bit(program[2])
        self.verify_declared_bit(program[4])
        self.verify_distinct([program[2], program[4]])
gate_op : CX id ',' id ';'