Update to mypy 1.2 (#6059)

Review: @viathor

cirq-core/cirq/_compat_test.py

@@ -98,7 +98,7 @@ def test_proper_repr_data_frame():
     pd.testing.assert_frame_equal(df2, df)
 
 
-def test_dataclass_repr_simple():
+def test_dataclass_repr_simple() -> None:
     @dataclasses.dataclass
     class TestClass1:
         x: int
@@ -111,7 +111,7 @@ def __repr__(self):
     assert repr(TestClass1(5, 'hi')) == "cirq.TestClass1(x=5, y='hi')"
 
 
-def test_dataclass_repr_numpy():
+def test_dataclass_repr_numpy() -> None:
     @dataclasses.dataclass
     class TestClass2:
         x: np.ndarray
@@ -1003,7 +1003,7 @@ def bar(self):
 
 
 class Bar:
-    def __init__(self):
+    def __init__(self) -> None:
         self.foo_calls: Dict[int, int] = collections.Counter()
         self.bar_calls: Dict[int, int] = collections.Counter()
 

cirq-core/cirq/circuits/circuit.py

@@ -305,7 +305,10 @@ def _first_moment_operating_on(
         return None
 
     def next_moment_operating_on(
-        self, qubits: Iterable['cirq.Qid'], start_moment_index: int = 0, max_distance: int = None
+        self,
+        qubits: Iterable['cirq.Qid'],
+        start_moment_index: int = 0,
+        max_distance: Optional[int] = None,
     ) -> Optional[int]:
         """Finds the index of the next moment that touches the given qubits.
 
@@ -2128,7 +2131,7 @@ def _push_frontier(
         self,
         early_frontier: Dict['cirq.Qid', int],
         late_frontier: Dict['cirq.Qid', int],
-        update_qubits: Iterable['cirq.Qid'] = None,
+        update_qubits: Optional[Iterable['cirq.Qid']] = None,
     ) -> Tuple[int, int]:
         """Inserts moments to separate two frontiers.
 
@@ -2198,7 +2201,10 @@ def _insert_operations(
             )
 
     def insert_at_frontier(
-        self, operations: 'cirq.OP_TREE', start: int, frontier: Dict['cirq.Qid', int] = None
+        self,
+        operations: 'cirq.OP_TREE',
+        start: int,
+        frontier: Optional[Dict['cirq.Qid', int]] = None,
     ) -> Dict['cirq.Qid', int]:
         """Inserts operations inline at frontier.
 
@@ -2389,7 +2395,9 @@ def with_noise(self, noise: 'cirq.NOISE_MODEL_LIKE') -> 'cirq.Circuit':
 
 
 def _pick_inserted_ops_moment_indices(
-    operations: Sequence['cirq.Operation'], start: int = 0, frontier: Dict['cirq.Qid', int] = None
+    operations: Sequence['cirq.Operation'],
+    start: int = 0,
+    frontier: Optional[Dict['cirq.Qid', int]] = None,
 ) -> Tuple[Sequence[int], Dict['cirq.Qid', int]]:
     """Greedily assigns operations to moments.
 

cirq-core/cirq/circuits/circuit_operation_test.py

@@ -274,7 +274,7 @@ def test_recursive_params():
 
 @pytest.mark.parametrize('add_measurements', [True, False])
 @pytest.mark.parametrize('use_default_ids_for_initial_rep', [True, False])
-def test_repeat(add_measurements, use_default_ids_for_initial_rep):
+def test_repeat(add_measurements: bool, use_default_ids_for_initial_rep: bool) -> None:
     a, b = cirq.LineQubit.range(2)
     circuit = cirq.Circuit(cirq.H(a), cirq.CX(a, b))
     if add_measurements:
@@ -327,9 +327,9 @@ def test_repeat(add_measurements, use_default_ids_for_initial_rep):
         _ = op_base.repeat()
 
     with pytest.raises(TypeError, match='Only integer or sympy repetitions are allowed'):
-        _ = op_base.repeat(1.3)
-    assert op_base.repeat(3.00000000001).repetitions == 3
-    assert op_base.repeat(2.99999999999).repetitions == 3
+        _ = op_base.repeat(1.3)  # type: ignore[arg-type]
+    assert op_base.repeat(3.00000000001).repetitions == 3  # type: ignore[arg-type]
+    assert op_base.repeat(2.99999999999).repetitions == 3  # type: ignore[arg-type]
 
 
 @pytest.mark.parametrize('add_measurements', [True, False])

cirq-core/cirq/circuits/text_diagram_drawer.py

@@ -292,7 +292,7 @@ def render(
         self,
         horizontal_spacing: int = 1,
         vertical_spacing: int = 1,
-        crossing_char: str = None,
+        crossing_char: Optional[str] = None,
         use_unicode_characters: bool = True,
     ) -> str:
         """Outputs text containing the diagram."""

cirq-core/cirq/contrib/acquaintance/executor.py

@@ -174,7 +174,10 @@ class GreedyExecutionStrategy(ExecutionStrategy):
     """
 
     def __init__(
-        self, gates: LogicalGates, initial_mapping: LogicalMapping, device: 'cirq.Device' = None
+        self,
+        gates: LogicalGates,
+        initial_mapping: LogicalMapping,
+        device: Optional['cirq.Device'] = None,
     ) -> None:
         """Inits GreedyExecutionStrategy.
 

cirq-core/cirq/contrib/acquaintance/permutation.py

@@ -13,7 +13,18 @@
 # limitations under the License.
 
 import abc
-from typing import Any, cast, Dict, Iterable, Sequence, Tuple, TypeVar, Union, TYPE_CHECKING
+from typing import (
+    Any,
+    cast,
+    Dict,
+    Iterable,
+    Optional,
+    Sequence,
+    Tuple,
+    TypeVar,
+    Union,
+    TYPE_CHECKING,
+)
 
 from cirq import circuits, ops, protocols, transformers, value
 from cirq.type_workarounds import NotImplementedType
@@ -72,7 +83,7 @@ def update_mapping(
                 mapping[new_key] = old_element
 
     @staticmethod
-    def validate_permutation(permutation: Dict[int, int], n_elements: int = None) -> None:
+    def validate_permutation(permutation: Dict[int, int], n_elements: Optional[int] = None) -> None:
         if not permutation:
             return
         if set(permutation.values()) != set(permutation):

cirq-core/cirq/contrib/qasm_import/_parser.py

@@ -141,7 +141,7 @@ class QasmParser:
         parsedQasm = QasmParser().parse(qasm)
     """
 
-    def __init__(self):
+    def __init__(self) -> None:
         self.parser = yacc.yacc(module=self, debug=False, write_tables=False)
         self.circuit = Circuit()
         self.qregs: Dict[str, int] = {}

cirq-core/cirq/contrib/quantum_volume/quantum_volume.py

@@ -200,7 +200,7 @@ def compile_circuit(
     *,
     device_graph: nx.Graph,
     routing_attempts: int,
-    compiler: Callable[[cirq.Circuit], cirq.Circuit] = None,
+    compiler: Optional[Callable[[cirq.Circuit], cirq.Circuit]] = None,
     routing_algo_name: Optional[str] = None,
     router: Optional[Callable[..., ccr.SwapNetwork]] = None,
     add_readout_error_correction=False,
@@ -357,7 +357,7 @@ def execute_circuits(
     samplers: List[cirq.Sampler],
     circuits: List[Tuple[cirq.Circuit, List[int]]],
     routing_attempts: int,
-    compiler: Callable[[cirq.Circuit], cirq.Circuit] = None,
+    compiler: Optional[Callable[[cirq.Circuit], cirq.Circuit]] = None,
     repetitions: int = 10_000,
     add_readout_error_correction=False,
 ) -> List[QuantumVolumeResult]:
@@ -429,7 +429,7 @@ def calculate_quantum_volume(
     device_graph: nx.Graph,
     samplers: List[cirq.Sampler],
     random_state: 'cirq.RANDOM_STATE_OR_SEED_LIKE' = None,
-    compiler: Callable[[cirq.Circuit], cirq.Circuit] = None,
+    compiler: Optional[Callable[[cirq.Circuit], cirq.Circuit]] = None,
     repetitions=10_000,
     routing_attempts=30,
     add_readout_error_correction=False,

cirq-core/cirq/contrib/quimb/mps_simulator.py

@@ -569,7 +569,7 @@ def __init__(
         simulation_options: MPSOptions = MPSOptions(),
         grouping: Optional[Dict['cirq.Qid', int]] = None,
         initial_state: int = 0,
-        classical_data: 'cirq.ClassicalDataStore' = None,
+        classical_data: Optional['cirq.ClassicalDataStore'] = None,
     ):
         """Creates and MPSState
 

cirq-core/cirq/contrib/svg/svg_test.py

@@ -1,5 +1,5 @@
 # pylint: disable=wrong-or-nonexistent-copyright-notice
-import IPython.display  # type: ignore
+import IPython.display  # type: ignore[import]
 import numpy as np
 import pytest
 

cirq-core/cirq/devices/grid_qubit.py

@@ -27,7 +27,7 @@
 TSelf = TypeVar('TSelf', bound='_BaseGridQid')
 
 
-@functools.total_ordering  # type: ignore
+@functools.total_ordering
 class _BaseGridQid(ops.Qid):
     """The Base class for `GridQid` and `GridQubit`."""
 

cirq-core/cirq/devices/line_qubit.py

@@ -25,7 +25,7 @@
 TSelf = TypeVar('TSelf', bound='_BaseLineQid')
 
 
-@functools.total_ordering  # type: ignore
+@functools.total_ordering
 class _BaseLineQid(ops.Qid):
     """The base class for `LineQid` and `LineQubit`."""
 

cirq-core/cirq/devices/named_topologies.py

@@ -345,7 +345,7 @@ def draw_placements(
     small_graph: nx.Graph,
     small_to_big_mappings: Sequence[Dict],
     max_plots: int = 20,
-    axes: Sequence[plt.Axes] = None,
+    axes: Optional[Sequence[plt.Axes]] = None,
     tilted: bool = True,
     bad_placement_callback: Optional[Callable[[plt.Axes, int], None]] = None,
 ):

cirq-core/cirq/devices/noise_model.py

@@ -125,6 +125,7 @@ def noisy_moments(
             A sequence of OP_TREEs, with the k'th tree corresponding to the
             noisy operations for the k'th moment.
         """
+        raise NotImplementedError
 
     def _noisy_moment_impl_moments(
         self, moment: 'cirq.Moment', system_qubits: Sequence['cirq.Qid']
@@ -150,6 +151,7 @@ def noisy_moment(
         Returns:
             An OP_TREE corresponding to the noisy operations for the moment.
         """
+        raise NotImplementedError
 
     def _noisy_operation_impl_moments(self, operation: 'cirq.Operation') -> 'cirq.OP_TREE':
         return self.noisy_moments([moment_module.Moment([operation])], operation.qubits)
@@ -169,6 +171,7 @@ def noisy_operation(self, operation: 'cirq.Operation') -> 'cirq.OP_TREE':
             An OP_TREE corresponding to the noisy operations implementing the
             noisy version of the given operation.
         """
+        raise NotImplementedError
 
 
 @value.value_equality

cirq-core/cirq/devices/superconducting_qubits_noise_properties.py

@@ -27,9 +27,7 @@
 
 
 # TODO: missing per-device defaults
-# Type-ignored because mypy cannot handle abstract dataclasses:
-# https://github.com/python/mypy/issues/5374
-@dataclass  # type: ignore
+@dataclass
 class SuperconductingQubitsNoiseProperties(devices.NoiseProperties, abc.ABC):
     """Noise-defining properties for a superconducting-qubit-based device.
 

cirq-core/cirq/experiments/n_qubit_tomography.py

@@ -134,7 +134,7 @@ def state_tomography(
     qubits: Sequence['cirq.Qid'],
     circuit: 'cirq.Circuit',
     repetitions: int = 1000,
-    prerotations: Sequence[Tuple[float, float]] = None,
+    prerotations: Optional[Sequence[Tuple[float, float]]] = None,
 ) -> TomographyResult:
     """This performs n qubit tomography on a cirq circuit
 

cirq-core/cirq/experiments/qubit_characterizations.py

@@ -542,8 +542,8 @@ def _matrix_bar_plot(
     mat: np.ndarray,
     z_label: str,
     ax: plt.Axes,
-    kets: Sequence[str] = None,
-    title: str = None,
+    kets: Optional[Sequence[str]] = None,
+    title: Optional[str] = None,
     ylim: Tuple[int, int] = (-1, 1),
     **bar3d_kwargs: Any,
 ) -> None:

cirq-core/cirq/experiments/single_qubit_readout_calibration.py

@@ -111,7 +111,7 @@ def estimate_parallel_single_qubit_readout_errors(
     trials: int = 20,
     repetitions: int = 1000,
     trials_per_batch: Optional[int] = None,
-    bit_strings: np.ndarray = None,
+    bit_strings: Optional[np.ndarray] = None,
 ) -> SingleQubitReadoutCalibrationResult:
     """Estimate single qubit readout error using parallel operations.
 

cirq-core/cirq/experiments/t2_decay_experiment.py

@@ -45,7 +45,7 @@ def t2_decay(
     min_delay: 'cirq.DURATION_LIKE' = None,
     repetitions: int = 1000,
     delay_sweep: Optional[study.Sweep] = None,
-    num_pulses: List[int] = None,
+    num_pulses: Optional[List[int]] = None,
 ) -> Union['cirq.experiments.T2DecayResult', List['cirq.experiments.T2DecayResult']]:
     """Runs a t2 transverse relaxation experiment.
 

cirq-core/cirq/interop/quirk/cells/testing.py

@@ -22,7 +22,7 @@
 
 def assert_url_to_circuit_returns(
     json_text: str,
-    circuit: 'cirq.Circuit' = None,
+    circuit: Optional['cirq.Circuit'] = None,
     *,
     unitary: Optional[np.ndarray] = None,
     diagram: Optional[str] = None,

cirq-core/cirq/linalg/transformations.py

@@ -249,7 +249,7 @@ def targeted_conjugate_about(
     tensor: np.ndarray,
     target: np.ndarray,
     indices: Sequence[int],
-    conj_indices: Sequence[int] = None,
+    conj_indices: Optional[Sequence[int]] = None,
     buffer: Optional[np.ndarray] = None,
     out: Optional[np.ndarray] = None,
 ) -> np.ndarray:

cirq-core/cirq/ops/clifford_gate.py

@@ -75,12 +75,6 @@ def _to_clifford_tableau(
     return clifford_tableau
 
 
-def _pretend_initialized() -> 'SingleQubitCliffordGate':
-    # HACK: This is a workaround to fool mypy and pylint into correctly handling
-    # class fields that can't be initialized until after the class is defined.
-    pass
-
-
 def _validate_map_input(
     required_transform_count: int,
     pauli_map_to: Optional[Dict[Pauli, Tuple[Pauli, bool]]],

cirq-core/cirq/ops/common_gates.py

@@ -187,7 +187,7 @@ def _trace_distance_bound_(self) -> Optional[float]:
 
     def controlled(
         self,
-        num_controls: int = None,
+        num_controls: Optional[int] = None,
         control_values: Optional[
             Union[cv.AbstractControlValues, Sequence[Union[int, Collection[int]]]]
         ] = None,
@@ -667,7 +667,7 @@ def with_canonical_global_phase(self) -> 'ZPowGate':
 
     def controlled(
         self,
-        num_controls: int = None,
+        num_controls: Optional[int] = None,
         control_values: Optional[
             Union[cv.AbstractControlValues, Sequence[Union[int, Collection[int]]]]
         ] = None,
@@ -1122,7 +1122,7 @@ def _phase_by_(self, phase_turns, qubit_index):
 
     def controlled(
         self,
-        num_controls: int = None,
+        num_controls: Optional[int] = None,
         control_values: Optional[
             Union[cv.AbstractControlValues, Sequence[Union[int, Collection[int]]]]
         ] = None,
@@ -1328,7 +1328,7 @@ def _pauli_expansion_(self) -> value.LinearDict[str]:
 
     def controlled(
         self,
-        num_controls: int = None,
+        num_controls: Optional[int] = None,
         control_values: Optional[
             Union[cv.AbstractControlValues, Sequence[Union[int, Collection[int]]]]
         ] = None,