Bound parametric circuits don't compile

[dowusu-antwi]

What is happening?

After a parametric circuit's parameters are bound, it's no longer parametric, but Superstaq tells users it still is.

How can we reproduce the issue?

import qiskit_superstaq as qss
provider = qss.SuperstaqProvider()
brisbane = provider.get_backend("ibmq_brisbane_qpu")

theta = qiskit.circuit.Parameter("θ")
qc = qiskit.QuantumCircuit(2, 2)
qc.append(qss.AceCR(theta), (0, 1))
qc.measure((0, 1), (0, 1))
#      ┌───────────┐┌─┐   
# q_0: ┤0          ├┤M├───
#      │  Acecr(θ) │└╥┘┌─┐
# q_1: ┤1          ├─╫─┤M├
#      └───────────┘ ║ └╥┘
# c: 2/══════════════╩══╩═
#                    0  1 

qc_bound = qc.assign_parameters({theta: np.pi / 3})
#      ┌─────────────┐┌─┐   
# q_0: ┤0            ├┤M├───
#      │  Acecr(π/3) │└╥┘┌─┐
# q_1: ┤1            ├─╫─┤M├
#      └─────────────┘ ║ └╥┘
# c: 2/════════════════╩══╩═
#                      0  1 
brisbane.compile(qc_bound)
# SuperstaqServerException: Can't convert parameterized unbounded qiskit circuits. Please let us know if you'd like this feature  
# (Status code: 400, non-retriable error making request to Superstaq API)

What should happen?

Bound circuits should be compiled with no issues.

brisbane.compile(qc_bound)  # This should work.

# C. f. working example, hard-coded parameter:
qc_hard_coded = qiskit.QuantumCircuit(2, 2)
qc_hard_coded.append(qss.AceCR(np.pi/3), (0, 1))
qc_hard_coded.measure((0, 1), (0, 1))
#      ┌─────────────┐┌─┐   
# q_0: ┤0            ├┤M├───
#      │  Acecr(π/3) │└╥┘┌─┐
# q_1: ┤1            ├─╫─┤M├
#      └─────────────┘ ║ └╥┘
# c: 2/════════════════╩══╩═
#                      0  1 
brisbane.compile(qc_hard_coded)  # This works.

FWIW, Qiskit treats a bound parameterized circuit and a circuit with hard-coded parameters differently (which I don't think was always true):

qc_bound == qc_hard_coded  # This returns False.

Environment

• Superstaq version: 0.5.18
• client-superstaq version: 0.5.15
• Operating system: Ubuntu 22.04.4
• Python version: 3.11
• Any other relevant dependencies: None

Any additional context?

Note: duplicate of server-side issue