Fix mypy errors (opflow)

qiskit/opflow/gradients/circuit_gradients/lin_comb.py

@@ -100,7 +100,7 @@ class LinComb(CircuitGradient):
     }
 
     # pylint: disable=signature-differs, arguments-differ
-    def __init__(self, aux_meas_op: OperatorBase = Z):
+    def __init__(self, aux_meas_op: OperatorBase = Z):  # type: ignore[override]
         """
         Args:
             aux_meas_op: The operator that the auxiliary qubit is measured with respect to.
@@ -751,7 +751,7 @@ def _gradient_states(
 
                         # compute the correct coefficient and append to list of circuits
                         coeff = np.sqrt(np.abs(grad_coeff)) * state_op.coeff
-                        state = CircuitStateFn(grad_circuit, coeff=coeff)
+                        state: OperatorBase = CircuitStateFn(grad_circuit, coeff=coeff)
 
                         # apply the chain rule if the parameter expression if required
                         param_expression = gate.params[idx]

qiskit/opflow/gradients/circuit_gradients/param_shift.py

@@ -92,7 +92,7 @@ def convert(
             Tuple[ParameterExpression, ParameterExpression],
             List[Tuple[ParameterExpression, ParameterExpression]],
         ],
-    ) -> OperatorBase:
+    ) -> OperatorBase:  # type: ignore[override]
         """
         Args:
             operator: The operator corresponding to our quantum state we are taking the

qiskit/opflow/gradients/circuit_qfis/lin_comb_full.py

@@ -40,7 +40,7 @@ def __init__(
         self,
         aux_meas_op: OperatorBase = Z,
         phase_fix: bool = True,
-    ):
+    ):  # type: ignore[override]
         """
         Args:
             aux_meas_op: The operator that the auxiliary qubit is measured with respect to.

qiskit/opflow/operator_base.py

@@ -47,7 +47,7 @@ class OperatorBase(StarAlgebraMixin, TensorMixin, ABC):
     def __init__(self) -> None:
         self._instance_id = next(self._count)
 
-    @property
+    @property  # type: ignore
     @abstractmethod
     def settings(self) -> Dict:
         """Return settings of this object in a dictionary.
@@ -66,7 +66,7 @@ def instance_id(self) -> int:
         """Return the unique instance id."""
         return self._instance_id
 
-    @property
+    @property  # type: ignore
     @abstractmethod
     def num_qubits(self) -> int:
         r"""The number of qubits over which the Operator is defined. If
@@ -309,7 +309,7 @@ def tensorpower(self, other: int) -> Union["OperatorBase", int]:
         """
         raise NotImplementedError
 
-    @property
+    @property  # type: ignore
     @abstractmethod
     def parameters(self):
         r"""Return a set of Parameter objects contained in the Operator."""

qiskit/opflow/primitive_ops/pauli_op.py

@@ -287,7 +287,7 @@ def exp_i(self) -> OperatorBase:
             return PauliOp(self.primitive)
         if np.sum(sig_qubits) == 1:
             sig_qubit_index = sig_qubits.tolist().index(True)
-            coeff = (
+            coeff: Union[float, ParameterExpression] = (
                 np.real(self.coeff)
                 if not isinstance(self.coeff, ParameterExpression)
                 else self.coeff

qiskit/opflow/state_fns/circuit_state_fn.py

@@ -11,8 +11,7 @@
 # that they have been altered from the originals.
 
 """ CircuitStateFn Class """
-
-
+import typing
 from typing import Dict, List, Optional, Set, Union, cast
 
 import numpy as np
@@ -47,7 +46,7 @@ class CircuitStateFn(StateFn):
     def __init__(
         self,
         primitive: Union[QuantumCircuit, Instruction] = None,
-        coeff: Union[complex, ParameterExpression] = 1.0,
+        coeff: Union[typing.SupportsComplex, ParameterExpression] = 1.0,
         is_measurement: bool = False,
         from_operator: bool = False,
     ) -> None: