Convert iterator to list to list before looping through moments r ops…

… in insert (quantumlib#5820)
PhaseCraft · Aug 8, 2022 · fb34de4 · fb34de4
1 parent 056e775
commit fb34de4
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diff --git a/cirq/circuits/circuit.py b/cirq/circuits/circuit.py
@@ -2083,7 +2083,7 @@ def insert(
         """
         # limit index to 0..len(self._moments), also deal with indices smaller 0
         k = max(min(index if index >= 0 else len(self._moments) + index, len(self._moments)), 0)
-        for moment_or_op in ops.flatten_to_ops_or_moments(moment_or_operation_tree):
+        for moment_or_op in list(ops.flatten_to_ops_or_moments(moment_or_operation_tree)):
             if isinstance(moment_or_op, Moment):
                 self._moments.insert(k, moment_or_op)
                 k += 1

diff --git a/cirq/circuits/circuit_test.py b/cirq/circuits/circuit_test.py
@@ -187,6 +187,12 @@ def test_append_single():
     c.append([cirq.X(a)])
     assert c == cirq.Circuit([cirq.Moment([cirq.X(a)])])
 
+    c = cirq.Circuit(cirq.H(a))
+    c.append(c)
+    assert c == cirq.Circuit(
+        [cirq.Moment(cirq.H(cirq.NamedQubit('a'))), cirq.Moment(cirq.H(cirq.NamedQubit('a')))]
+    )
+
 
 def test_append_control_key():
     q0, q1, q2 = cirq.LineQubit.range(3)