Add missing properties in _mutated

Author: maffoo

cirq-core/cirq/circuits/circuit.py

@@ -1777,7 +1777,9 @@ def _mutated(self) -> None:
         """Clear cached properties in response to this circuit being mutated."""
         self._all_qubits = None
         self._frozen = None
+        self._is_measurement = None
         self._is_parameterized = None
+        self._parameter_names = None
 
     @classmethod
     def _from_moments(cls, moments: Iterable['cirq.Moment']) -> 'Circuit':

cirq-core/cirq/circuits/circuit_test.py

@@ -4533,7 +4533,7 @@ def test_freeze_not_relocate_moments():
     assert [mc is fc for mc, fc in zip(c, f)] == [True, True]
 
 
-def test_freeze_returns_same_instance_if_not_mutated():
+def test_freeze_is_cached():
     q = cirq.q(0)
     c = cirq.Circuit(cirq.X(q), cirq.measure(q))
     f0 = c.freeze()