Environment

• Qiskit version: 2.0.0rc1
• Python version: 3.9
• Operating system: linux

What is happening?

The Aer unit test suite shows an error trace that points to quantumcircuit.py:

File "/opt/hostedtoolcache/Python/3.10.16/x64/lib/python3.10/site-packages/qiskit/circuit/quantumcircuit.py", line 3892, in _create_creg
new_creg = ClassicalRegister(length, name=f"{name}{ClassicalRegister.instance_count}")
AttributeError: type object 'qiskit.circuit.ClassicalRegister' has no attribute 'instance_count'

This is apparently a typo in the attribute name, which is instances_count instead of 'instance_count'.

How can we reproduce the issue?

Issue found when running qiskit-aer/test/terra/primitives/test_estimator.py

What should happen?

No typo

Any suggestions?

No response