Qiskit does not interpret qasm string as 3.0?

Question

I am trying to get my first openqasm3.0 program and I am getting error messages that I cannot interpret.

Here is my program:

cloner1 = """
OPENQASM 3.0;
//include "qelib1.inc";
qubit[5] q;
bit[1] c;
x q[2];
x q[4];

x q[0]; //Set up input
measure q[0] -> c[0];
if (c[0]==1) {
    CX q[1],q[2];
    CX q[2],q[1];
    CX q[1],q[2];
    CX q[3],q[4];
    CX q[4],q[3];
    CX q[3],q[4];
    }
measure q[1]->c[0];
measure q[3]->c[0];
"""

qc= QuantumCircuit.from_qasm_str(cloner1)
result = execute(qc, backend=qiskit.BasicAer.get_backend('qasm_simulator'),shots=1024).result()
counts = result.get_counts()
plot_histogram(counts)

THe error message I get is Error near line 4 Column 7 Expected an ID, received '['"

Apparently it doesn't like bit[1] c. But this is just like the code in the arxiv.org article

So I don't know what is wrong. It doesn't seem to be interpreting it as ASM3.0 code.

Answer 1

OpenQASM 3.0 is still in pre-release: https://github.com/Qiskit/openqasm/releases

I believe your observation is correct - your code is not interpreted as OpenQASM 3.0. Another test: the first example from Github starts with OPENQASM 3; (not 3.0.) Even trying this now I get

QasmError: Unable to match any token rule, got -->O<-- Check your OPENQASM source and any include statements.

hence I am confident Qiskit tries to run it as 2.0 when it does not recognize version. I have opened this issue on GitHub requesting that QASM throws an error if an unavailable version is requested.