From 8a466ac2863addacbb600d10e69a6c76a6f49b6a Mon Sep 17 00:00:00 2001
From: Richard Shadrach <rhshadrach@gmail.com>
Date: Sun, 15 Nov 2020 21:42:39 -0500
Subject: [PATCH 1/7] TYP: Add cast to ABC classes.

---
 pandas/core/algorithms.py             |  4 ++--
 pandas/core/base.py                   |  6 ++++--
 pandas/core/computation/align.py      | 13 ++++++++-----
 pandas/core/computation/parsing.py    |  7 +++++--
 pandas/core/construction.py           | 16 +++++++++-------
 pandas/core/dtypes/generic.py         | 21 ++++++++++++++++++---
 pandas/core/generic.py                |  5 ++---
 pandas/core/indexing.py               |  2 +-
 pandas/core/internals/construction.py |  2 +-
 pandas/core/reshape/concat.py         | 20 ++++++++++++++++----
 pandas/core/strings/accessor.py       |  3 +--
 pandas/core/window/common.py          |  3 +++
 pandas/plotting/_matplotlib/tools.py  | 10 +++++-----
 13 files changed, 75 insertions(+), 37 deletions(-)

diff --git a/pandas/core/algorithms.py b/pandas/core/algorithms.py
index ec88eb817b3f8..f7f575ea1c29c 100644
--- a/pandas/core/algorithms.py
+++ b/pandas/core/algorithms.py
@@ -60,7 +60,7 @@
 from pandas.core.indexers import validate_indices
 
 if TYPE_CHECKING:
-    from pandas import Categorical, DataFrame, Series
+    from pandas import Categorical, DataFrame, Index, Series
 
 _shared_docs: Dict[str, str] = {}
 
@@ -533,7 +533,7 @@ def factorize(
     sort: bool = False,
     na_sentinel: Optional[int] = -1,
     size_hint: Optional[int] = None,
-) -> Tuple[np.ndarray, Union[np.ndarray, ABCIndex]]:
+) -> Tuple[np.ndarray, Union[np.ndarray, "Index"]]:
     """
     Encode the object as an enumerated type or categorical variable.
 
diff --git a/pandas/core/base.py b/pandas/core/base.py
index b3366cca37617..a4d954e12459a 100644
--- a/pandas/core/base.py
+++ b/pandas/core/base.py
@@ -269,12 +269,14 @@ def __getitem__(self, key):
             return self._gotitem(list(key), ndim=2)
 
         elif not getattr(self, "as_index", False):
-            if key not in self.obj.columns:
+            # error: "SelectionMixin" has no attribute "obj"  [attr-defined]
+            if key not in self.obj.columns:  # type: ignore[attr-defined]
                 raise KeyError(f"Column not found: {key}")
             return self._gotitem(key, ndim=2)
 
         else:
-            if key not in self.obj:
+            # error: "SelectionMixin" has no attribute "obj"  [attr-defined]
+            if key not in self.obj:  # type: ignore[attr-defined]
                 raise KeyError(f"Column not found: {key}")
             return self._gotitem(key, ndim=1)
 
diff --git a/pandas/core/computation/align.py b/pandas/core/computation/align.py
index 8a8b0d564ea49..1ecb373a3a91e 100644
--- a/pandas/core/computation/align.py
+++ b/pandas/core/computation/align.py
@@ -3,7 +3,7 @@
 """
 
 from functools import partial, wraps
-from typing import Dict, Optional, Sequence, Tuple, Type, Union
+from typing import TYPE_CHECKING, Dict, List, Optional, Tuple, Type, Union
 import warnings
 
 import numpy as np
@@ -17,13 +17,16 @@
 import pandas.core.common as com
 from pandas.core.computation.common import result_type_many
 
+if TYPE_CHECKING:
+    from pandas.core.indexes.api import Index
+
 
 def _align_core_single_unary_op(
     term,
-) -> Tuple[Union[partial, Type[FrameOrSeries]], Optional[Dict[str, int]]]:
+) -> Tuple[Union[partial, Type[FrameOrSeries]], Optional[Dict[str, "Index"]]]:
 
     typ: Union[partial, Type[FrameOrSeries]]
-    axes: Optional[Dict[str, int]] = None
+    axes: Optional[Dict[str, "Index"]] = None
 
     if isinstance(term.value, np.ndarray):
         typ = partial(np.asanyarray, dtype=term.value.dtype)
@@ -36,8 +39,8 @@ def _align_core_single_unary_op(
 
 
 def _zip_axes_from_type(
-    typ: Type[FrameOrSeries], new_axes: Sequence[int]
-) -> Dict[str, int]:
+    typ: Type[FrameOrSeries], new_axes: List["Index"]
+) -> Dict[str, "Index"]:
     return {name: new_axes[i] for i, name in enumerate(typ._AXIS_ORDERS)}
 
 
diff --git a/pandas/core/computation/parsing.py b/pandas/core/computation/parsing.py
index 86e125b6b909b..cff49637bd257 100644
--- a/pandas/core/computation/parsing.py
+++ b/pandas/core/computation/parsing.py
@@ -6,11 +6,14 @@
 from keyword import iskeyword
 import token
 import tokenize
-from typing import Iterator, Tuple
+from typing import TYPE_CHECKING, Iterator, Tuple
 
 # A token value Python's tokenizer probably will never use.
 BACKTICK_QUOTED_STRING = 100
 
+if TYPE_CHECKING:
+    from pandas._typing import Label
+
 
 def create_valid_python_identifier(name: str) -> str:
     """
@@ -91,7 +94,7 @@ def clean_backtick_quoted_toks(tok: Tuple[int, str]) -> Tuple[int, str]:
     return toknum, tokval
 
 
-def clean_column_name(name: str) -> str:
+def clean_column_name(name: "Label") -> "Label":
     """
     Function to emulate the cleaning of a backtick quoted name.
 
diff --git a/pandas/core/construction.py b/pandas/core/construction.py
index 7901e150a7ff4..9cf31e1d9a52b 100644
--- a/pandas/core/construction.py
+++ b/pandas/core/construction.py
@@ -351,7 +351,9 @@ def array(
     return result
 
 
-def extract_array(obj: AnyArrayLike, extract_numpy: bool = False) -> ArrayLike:
+def extract_array(
+    obj: AnyArrayLike, extract_numpy: bool = False
+) -> Union[AnyArrayLike, ExtensionArray, np.ndarray]:
     """
     Extract the ndarray or ExtensionArray from a Series or Index.
 
@@ -394,14 +396,14 @@ def extract_array(obj: AnyArrayLike, extract_numpy: bool = False) -> ArrayLike:
     array([1, 2, 3])
     """
     if isinstance(obj, (ABCIndexClass, ABCSeries)):
-        obj = obj.array
+        result = obj.array
+    else:
+        result = obj
 
-    if extract_numpy and isinstance(obj, ABCPandasArray):
-        obj = obj.to_numpy()
+    if extract_numpy and isinstance(result, ABCPandasArray):
+        result = result.to_numpy()
 
-    # error: Incompatible return value type (got "Index", expected "ExtensionArray")
-    # error: Incompatible return value type (got "Series", expected "ExtensionArray")
-    return obj  # type: ignore[return-value]
+    return result
 
 
 def sanitize_array(
diff --git a/pandas/core/dtypes/generic.py b/pandas/core/dtypes/generic.py
index 7d2549713c6bc..d9050d1600580 100644
--- a/pandas/core/dtypes/generic.py
+++ b/pandas/core/dtypes/generic.py
@@ -1,5 +1,12 @@
 """ define generic base classes for pandas objects """
 
+from typing import TYPE_CHECKING, Type, cast
+
+if TYPE_CHECKING:
+    from pandas.core.frame import DataFrame
+    from pandas.core.generic import NDFrame
+    from pandas.core.series import Series
+
 
 # define abstract base classes to enable isinstance type checking on our
 # objects
@@ -53,9 +60,17 @@ def _check(cls, inst) -> bool:
     },
 )
 
-ABCNDFrame = create_pandas_abc_type("ABCNDFrame", "_typ", ("series", "dataframe"))
-ABCSeries = create_pandas_abc_type("ABCSeries", "_typ", ("series",))
-ABCDataFrame = create_pandas_abc_type("ABCDataFrame", "_typ", ("dataframe",))
+ABCNDFrame = cast(
+    "Type[NDFrame]",
+    create_pandas_abc_type("ABCNDFrame", "_typ", ("series", "dataframe")),
+)
+ABCSeries = cast(
+    "Type[Series]",
+    create_pandas_abc_type("ABCSeries", "_typ", ("series",)),
+)
+ABCDataFrame = cast(
+    "Type[DataFrame]", create_pandas_abc_type("ABCDataFrame", "_typ", ("dataframe",))
+)
 
 ABCCategorical = create_pandas_abc_type("ABCCategorical", "_typ", ("categorical"))
 ABCDatetimeArray = create_pandas_abc_type("ABCDatetimeArray", "_typ", ("datetimearray"))
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 4e6aba1961b64..fee143816164d 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -511,7 +511,7 @@ def _get_axis_resolvers(self, axis: str) -> Dict[str, Union[Series, MultiIndex]]
         return d
 
     @final
-    def _get_index_resolvers(self) -> Dict[str, Union[Series, MultiIndex]]:
+    def _get_index_resolvers(self) -> Dict[Label, Union[Series, MultiIndex]]:
         from pandas.core.computation.parsing import clean_column_name
 
         d: Dict[str, Union[Series, MultiIndex]] = {}
@@ -521,7 +521,7 @@ def _get_index_resolvers(self) -> Dict[str, Union[Series, MultiIndex]]:
         return {clean_column_name(k): v for k, v in d.items() if not isinstance(k, int)}
 
     @final
-    def _get_cleaned_column_resolvers(self) -> Dict[str, ABCSeries]:
+    def _get_cleaned_column_resolvers(self) -> Dict[Label, Series]:
         """
         Return the special character free column resolvers of a dataframe.
 
@@ -532,7 +532,6 @@ def _get_cleaned_column_resolvers(self) -> Dict[str, ABCSeries]:
         from pandas.core.computation.parsing import clean_column_name
 
         if isinstance(self, ABCSeries):
-            self = cast("Series", self)
             return {clean_column_name(self.name): self}
 
         return {
diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
index a8951e342e0da..47283375beaa3 100644
--- a/pandas/core/indexing.py
+++ b/pandas/core/indexing.py
@@ -2016,7 +2016,7 @@ def ravel(i):
 
         raise ValueError("Incompatible indexer with Series")
 
-    def _align_frame(self, indexer, df: ABCDataFrame):
+    def _align_frame(self, indexer, df: "DataFrame"):
         is_frame = self.ndim == 2
 
         if isinstance(indexer, tuple):
diff --git a/pandas/core/internals/construction.py b/pandas/core/internals/construction.py
index bcafa2c2fdca7..6e88501a1f287 100644
--- a/pandas/core/internals/construction.py
+++ b/pandas/core/internals/construction.py
@@ -369,7 +369,7 @@ def extract_index(data) -> Index:
         index = Index([])
     elif len(data) > 0:
         raw_lengths = []
-        indexes = []
+        indexes: List[Any] = []
 
         have_raw_arrays = False
         have_series = False
diff --git a/pandas/core/reshape/concat.py b/pandas/core/reshape/concat.py
index 77b1076920f20..e20d65eefbbe6 100644
--- a/pandas/core/reshape/concat.py
+++ b/pandas/core/reshape/concat.py
@@ -3,11 +3,21 @@
 """
 
 from collections import abc
-from typing import TYPE_CHECKING, Iterable, List, Mapping, Type, Union, cast, overload
+from typing import (
+    TYPE_CHECKING,
+    Iterable,
+    List,
+    Mapping,
+    Optional,
+    Type,
+    Union,
+    cast,
+    overload,
+)
 
 import numpy as np
 
-from pandas._typing import FrameOrSeries, FrameOrSeriesUnion, Label
+from pandas._typing import FrameOrSeriesUnion, Label
 
 from pandas.core.dtypes.concat import concat_compat
 from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries
@@ -295,7 +305,7 @@ class _Concatenator:
 
     def __init__(
         self,
-        objs: Union[Iterable[FrameOrSeries], Mapping[Label, FrameOrSeries]],
+        objs: Union[Iterable["NDFrame"], Mapping[Label, "NDFrame"]],
         axis=0,
         join: str = "outer",
         keys=None,
@@ -366,7 +376,7 @@ def __init__(
         # get the sample
         # want the highest ndim that we have, and must be non-empty
         # unless all objs are empty
-        sample = None
+        sample: Optional["NDFrame"] = None
         if len(ndims) > 1:
             max_ndim = max(ndims)
             for obj in objs:
@@ -436,6 +446,8 @@ def __init__(
                     # to line up
                     if self._is_frame and axis == 1:
                         name = 0
+                    # mypy needs to know sample is not an NDFrame
+                    assert isinstance(sample, (ABCSeries, ABCDataFrame))
                     obj = sample._constructor({name: obj})
 
                 self.objs.append(obj)
diff --git a/pandas/core/strings/accessor.py b/pandas/core/strings/accessor.py
index 7d6a2bf1d776d..9d16beba669ca 100644
--- a/pandas/core/strings/accessor.py
+++ b/pandas/core/strings/accessor.py
@@ -157,11 +157,10 @@ def __init__(self, data):
         array = data.array
         self._array = array
 
+        self._index = self._name = None
         if isinstance(data, ABCSeries):
             self._index = data.index
             self._name = data.name
-        else:
-            self._index = self._name = None
 
         # ._values.categories works for both Series/Index
         self._parent = data._values.categories if self._is_categorical else data
diff --git a/pandas/core/window/common.py b/pandas/core/window/common.py
index 938f1846230cb..080e9a5fa34e7 100644
--- a/pandas/core/window/common.py
+++ b/pandas/core/window/common.py
@@ -109,6 +109,9 @@ def dataframe_from_int_dict(data, frame_template):
 
                     # set the index and reorder
                     if arg2.columns.nlevels > 1:
+                        # mypy needs to know columns is a MultiIndex, Index doesn't
+                        # have levels attribute
+                        assert isinstance(arg2.columns, MultiIndex)
                         result.index = MultiIndex.from_product(
                             arg2.columns.levels + [result_index]
                         )
diff --git a/pandas/plotting/_matplotlib/tools.py b/pandas/plotting/_matplotlib/tools.py
index bec1f48f5e64a..6f926abf57da5 100644
--- a/pandas/plotting/_matplotlib/tools.py
+++ b/pandas/plotting/_matplotlib/tools.py
@@ -32,19 +32,19 @@ def format_date_labels(ax: "Axes", rot):
 
 def table(ax, data: FrameOrSeries, rowLabels=None, colLabels=None, **kwargs) -> "Table":
     if isinstance(data, ABCSeries):
-        data = data.to_frame()
+        frame = data.to_frame()
     elif isinstance(data, ABCDataFrame):
-        pass
+        frame = data
     else:
         raise ValueError("Input data must be DataFrame or Series")
 
     if rowLabels is None:
-        rowLabels = data.index
+        rowLabels = frame.index
 
     if colLabels is None:
-        colLabels = data.columns
+        colLabels = frame.columns
 
-    cellText = data.values
+    cellText = frame.values
 
     table = matplotlib.table.table(
         ax, cellText=cellText, rowLabels=rowLabels, colLabels=colLabels, **kwargs

From 99c9e6ba66086efa8932ffc41cf7cff8dee7645f Mon Sep 17 00:00:00 2001
From: Richard Shadrach <rhshadrach@gmail.com>
Date: Tue, 17 Nov 2020 20:51:28 -0500
Subject: [PATCH 2/7] Feedback fixes

---
 pandas/core/common.py              |  3 ++-
 pandas/core/computation/align.py   |  4 ++--
 pandas/core/computation/parsing.py | 11 +++++------
 pandas/core/construction.py        |  2 +-
 pandas/core/dtypes/generic.py      |  4 +---
 pandas/core/reshape/concat.py      |  2 +-
 pandas/core/window/common.py       |  3 ++-
 7 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/pandas/core/common.py b/pandas/core/common.py
index d5c078b817ca0..09ed2005cd028 100644
--- a/pandas/core/common.py
+++ b/pandas/core/common.py
@@ -469,7 +469,8 @@ def convert_to_list_like(
     inputs are returned unmodified whereas others are converted to list.
     """
     if isinstance(values, (list, np.ndarray, ABCIndex, ABCSeries, ABCExtensionArray)):
-        return values
+        # np.ndarray resolving as Any gives a false positive
+        return values  # type: ignore[return-value]
     elif isinstance(values, abc.Iterable) and not isinstance(values, str):
         return list(values)
 
diff --git a/pandas/core/computation/align.py b/pandas/core/computation/align.py
index 1ecb373a3a91e..efb7c139cedec 100644
--- a/pandas/core/computation/align.py
+++ b/pandas/core/computation/align.py
@@ -3,7 +3,7 @@
 """
 
 from functools import partial, wraps
-from typing import TYPE_CHECKING, Dict, List, Optional, Tuple, Type, Union
+from typing import TYPE_CHECKING, Dict, Optional, Sequence, Tuple, Type, Union
 import warnings
 
 import numpy as np
@@ -39,7 +39,7 @@ def _align_core_single_unary_op(
 
 
 def _zip_axes_from_type(
-    typ: Type[FrameOrSeries], new_axes: List["Index"]
+    typ: Type[FrameOrSeries], new_axes: Sequence["Index"]
 ) -> Dict[str, "Index"]:
     return {name: new_axes[i] for i, name in enumerate(typ._AXIS_ORDERS)}
 
diff --git a/pandas/core/computation/parsing.py b/pandas/core/computation/parsing.py
index cff49637bd257..32d21929b1996 100644
--- a/pandas/core/computation/parsing.py
+++ b/pandas/core/computation/parsing.py
@@ -6,14 +6,13 @@
 from keyword import iskeyword
 import token
 import tokenize
-from typing import TYPE_CHECKING, Iterator, Tuple
+from typing import Iterator, Tuple
+
+from pandas._typing import Label
 
 # A token value Python's tokenizer probably will never use.
 BACKTICK_QUOTED_STRING = 100
 
-if TYPE_CHECKING:
-    from pandas._typing import Label
-
 
 def create_valid_python_identifier(name: str) -> str:
     """
@@ -105,12 +104,12 @@ def clean_column_name(name: "Label") -> "Label":
 
     Parameters
     ----------
-    name : str
+    name : Label
         Name to be cleaned.
 
     Returns
     -------
-    name : str
+    name : Label
         Returns the name after tokenizing and cleaning.
 
     Notes
diff --git a/pandas/core/construction.py b/pandas/core/construction.py
index 9cf31e1d9a52b..df3cd414d8b90 100644
--- a/pandas/core/construction.py
+++ b/pandas/core/construction.py
@@ -353,7 +353,7 @@ def array(
 
 def extract_array(
     obj: AnyArrayLike, extract_numpy: bool = False
-) -> Union[AnyArrayLike, ExtensionArray, np.ndarray]:
+) -> Union[ExtensionArray, np.ndarray]:
     """
     Extract the ndarray or ExtensionArray from a Series or Index.
 
diff --git a/pandas/core/dtypes/generic.py b/pandas/core/dtypes/generic.py
index d9050d1600580..36b20f19f8e98 100644
--- a/pandas/core/dtypes/generic.py
+++ b/pandas/core/dtypes/generic.py
@@ -3,9 +3,7 @@
 from typing import TYPE_CHECKING, Type, cast
 
 if TYPE_CHECKING:
-    from pandas.core.frame import DataFrame
-    from pandas.core.generic import NDFrame
-    from pandas.core.series import Series
+    from pandas import DataFrame, NDFrame, Series
 
 
 # define abstract base classes to enable isinstance type checking on our
diff --git a/pandas/core/reshape/concat.py b/pandas/core/reshape/concat.py
index e20d65eefbbe6..a05c4270ff0c3 100644
--- a/pandas/core/reshape/concat.py
+++ b/pandas/core/reshape/concat.py
@@ -447,7 +447,7 @@ def __init__(
                     if self._is_frame and axis == 1:
                         name = 0
                     # mypy needs to know sample is not an NDFrame
-                    assert isinstance(sample, (ABCSeries, ABCDataFrame))
+                    sample = cast("FrameOrSeriesUnion", sample)
                     obj = sample._constructor({name: obj})
 
                 self.objs.append(obj)
diff --git a/pandas/core/window/common.py b/pandas/core/window/common.py
index 080e9a5fa34e7..6ebf610587d30 100644
--- a/pandas/core/window/common.py
+++ b/pandas/core/window/common.py
@@ -1,5 +1,6 @@
 """Common utility functions for rolling operations"""
 from collections import defaultdict
+from typing import cast
 import warnings
 
 import numpy as np
@@ -111,7 +112,7 @@ def dataframe_from_int_dict(data, frame_template):
                     if arg2.columns.nlevels > 1:
                         # mypy needs to know columns is a MultiIndex, Index doesn't
                         # have levels attribute
-                        assert isinstance(arg2.columns, MultiIndex)
+                        arg2.columns = cast(MultiIndex, arg2.columns)
                         result.index = MultiIndex.from_product(
                             arg2.columns.levels + [result_index]
                         )

From f8a76bc8f2338b1185e7c5ab1ed5399924e99b30 Mon Sep 17 00:00:00 2001
From: Richard Shadrach <rhshadrach@gmail.com>
Date: Wed, 18 Nov 2020 17:25:49 -0500
Subject: [PATCH 3/7] Revert changes using FrameOrSeriesUnion; lambda to work
 around internal error

---
 pandas/core/base.py                  |  7 +++----
 pandas/plotting/_matplotlib/tools.py | 16 +++++++++-------
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/pandas/core/base.py b/pandas/core/base.py
index a4d954e12459a..5f724d9e89d05 100644
--- a/pandas/core/base.py
+++ b/pandas/core/base.py
@@ -921,10 +921,9 @@ def _map_values(self, mapper, na_action=None):
             # "astype"  [attr-defined]
             values = self.astype(object)._values  # type: ignore[attr-defined]
             if na_action == "ignore":
-
-                def map_f(values, f):
-                    return lib.map_infer_mask(values, f, isna(values).view(np.uint8))
-
+                map_f = lambda values, f: lib.map_infer_mask(
+                    values, f, isna(values).view(np.uint8)
+                )
             elif na_action is None:
                 map_f = lib.map_infer
             else:
diff --git a/pandas/plotting/_matplotlib/tools.py b/pandas/plotting/_matplotlib/tools.py
index 6f926abf57da5..b8fc93d9aba93 100644
--- a/pandas/plotting/_matplotlib/tools.py
+++ b/pandas/plotting/_matplotlib/tools.py
@@ -7,7 +7,7 @@
 import matplotlib.ticker as ticker
 import numpy as np
 
-from pandas._typing import FrameOrSeries
+from pandas._typing import FrameOrSeriesUnion
 
 from pandas.core.dtypes.common import is_list_like
 from pandas.core.dtypes.generic import ABCDataFrame, ABCIndexClass, ABCSeries
@@ -30,21 +30,23 @@ def format_date_labels(ax: "Axes", rot):
     fig.subplots_adjust(bottom=0.2)
 
 
-def table(ax, data: FrameOrSeries, rowLabels=None, colLabels=None, **kwargs) -> "Table":
+def table(
+    ax, data: FrameOrSeriesUnion, rowLabels=None, colLabels=None, **kwargs
+) -> "Table":
     if isinstance(data, ABCSeries):
-        frame = data.to_frame()
+        data = data.to_frame()
     elif isinstance(data, ABCDataFrame):
-        frame = data
+        pass
     else:
         raise ValueError("Input data must be DataFrame or Series")
 
     if rowLabels is None:
-        rowLabels = frame.index
+        rowLabels = data.index
 
     if colLabels is None:
-        colLabels = frame.columns
+        colLabels = data.columns
 
-    cellText = frame.values
+    cellText = data.values
 
     table = matplotlib.table.table(
         ax, cellText=cellText, rowLabels=rowLabels, colLabels=colLabels, **kwargs

From c9a31a4e89a379e141760352cdb14f548e1b6899 Mon Sep 17 00:00:00 2001
From: Richard Shadrach <rhshadrach@gmail.com>
Date: Sun, 22 Nov 2020 12:42:42 -0500
Subject: [PATCH 4/7] Implementation revert and docstring type

---
 pandas/core/computation/parsing.py |  4 ++--
 pandas/core/construction.py        | 10 ++++------
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/pandas/core/computation/parsing.py b/pandas/core/computation/parsing.py
index 32d21929b1996..a1bebc92046ae 100644
--- a/pandas/core/computation/parsing.py
+++ b/pandas/core/computation/parsing.py
@@ -104,12 +104,12 @@ def clean_column_name(name: "Label") -> "Label":
 
     Parameters
     ----------
-    name : Label
+    name : hashable
         Name to be cleaned.
 
     Returns
     -------
-    name : Label
+    name : hashable
         Returns the name after tokenizing and cleaning.
 
     Notes
diff --git a/pandas/core/construction.py b/pandas/core/construction.py
index df3cd414d8b90..04683ba0869d0 100644
--- a/pandas/core/construction.py
+++ b/pandas/core/construction.py
@@ -396,14 +396,12 @@ def extract_array(
     array([1, 2, 3])
     """
     if isinstance(obj, (ABCIndexClass, ABCSeries)):
-        result = obj.array
-    else:
-        result = obj
+        obj = obj.array  # type: ignore[assignment]
 
-    if extract_numpy and isinstance(result, ABCPandasArray):
-        result = result.to_numpy()
+    if extract_numpy and isinstance(obj, ABCPandasArray):
+        obj = obj.to_numpy()
 
-    return result
+    return obj
 
 
 def sanitize_array(

From 1ac7c9e4af74e76b3a6d3490bba7fc2a868522fb Mon Sep 17 00:00:00 2001
From: Richard Shadrach <rhshadrach@gmail.com>
Date: Sun, 22 Nov 2020 16:41:28 -0500
Subject: [PATCH 5/7] Fix extract_array typing

---
 pandas/core/construction.py | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/pandas/core/construction.py b/pandas/core/construction.py
index 04683ba0869d0..f9ebe3f1e185e 100644
--- a/pandas/core/construction.py
+++ b/pandas/core/construction.py
@@ -351,9 +351,7 @@ def array(
     return result
 
 
-def extract_array(
-    obj: AnyArrayLike, extract_numpy: bool = False
-) -> Union[ExtensionArray, np.ndarray]:
+def extract_array(obj: object, extract_numpy: bool = False) -> Union[Any, ArrayLike]:
     """
     Extract the ndarray or ExtensionArray from a Series or Index.
 
@@ -396,7 +394,7 @@ def extract_array(
     array([1, 2, 3])
     """
     if isinstance(obj, (ABCIndexClass, ABCSeries)):
-        obj = obj.array  # type: ignore[assignment]
+        obj = obj.array
 
     if extract_numpy and isinstance(obj, ABCPandasArray):
         obj = obj.to_numpy()

From 2ba5fbeed4e51914c767bc6aea6ba38f798d93f0 Mon Sep 17 00:00:00 2001
From: Richard Shadrach <rhshadrach@gmail.com>
Date: Mon, 23 Nov 2020 10:16:55 -0500
Subject: [PATCH 6/7] future annotations, better typing of indexes

---
 pandas/core/computation/align.py      | 9 +++++----
 pandas/core/dtypes/generic.py         | 7 ++++---
 pandas/core/internals/construction.py | 2 +-
 3 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/pandas/core/computation/align.py b/pandas/core/computation/align.py
index efb7c139cedec..5ad3e78a76866 100644
--- a/pandas/core/computation/align.py
+++ b/pandas/core/computation/align.py
@@ -1,6 +1,7 @@
 """
 Core eval alignment algorithms.
 """
+from __future__ import annotations
 
 from functools import partial, wraps
 from typing import TYPE_CHECKING, Dict, Optional, Sequence, Tuple, Type, Union
@@ -23,10 +24,10 @@
 
 def _align_core_single_unary_op(
     term,
-) -> Tuple[Union[partial, Type[FrameOrSeries]], Optional[Dict[str, "Index"]]]:
+) -> Tuple[Union[partial, Type[FrameOrSeries]], Optional[Dict[str, Index]]]:
 
     typ: Union[partial, Type[FrameOrSeries]]
-    axes: Optional[Dict[str, "Index"]] = None
+    axes: Optional[Dict[str, Index]] = None
 
     if isinstance(term.value, np.ndarray):
         typ = partial(np.asanyarray, dtype=term.value.dtype)
@@ -39,8 +40,8 @@ def _align_core_single_unary_op(
 
 
 def _zip_axes_from_type(
-    typ: Type[FrameOrSeries], new_axes: Sequence["Index"]
-) -> Dict[str, "Index"]:
+    typ: Type[FrameOrSeries], new_axes: Sequence[Index]
+) -> Dict[str, Index]:
     return {name: new_axes[i] for i, name in enumerate(typ._AXIS_ORDERS)}
 
 
diff --git a/pandas/core/dtypes/generic.py b/pandas/core/dtypes/generic.py
index 36b20f19f8e98..daf205237a42e 100644
--- a/pandas/core/dtypes/generic.py
+++ b/pandas/core/dtypes/generic.py
@@ -1,4 +1,5 @@
 """ define generic base classes for pandas objects """
+from __future__ import annotations
 
 from typing import TYPE_CHECKING, Type, cast
 
@@ -59,15 +60,15 @@ def _check(cls, inst) -> bool:
 )
 
 ABCNDFrame = cast(
-    "Type[NDFrame]",
+    Type[NDFrame],
     create_pandas_abc_type("ABCNDFrame", "_typ", ("series", "dataframe")),
 )
 ABCSeries = cast(
-    "Type[Series]",
+    Type[Series],
     create_pandas_abc_type("ABCSeries", "_typ", ("series",)),
 )
 ABCDataFrame = cast(
-    "Type[DataFrame]", create_pandas_abc_type("ABCDataFrame", "_typ", ("dataframe",))
+    Type[DataFrame], create_pandas_abc_type("ABCDataFrame", "_typ", ("dataframe",))
 )
 
 ABCCategorical = create_pandas_abc_type("ABCCategorical", "_typ", ("categorical"))
diff --git a/pandas/core/internals/construction.py b/pandas/core/internals/construction.py
index 6e88501a1f287..18c5452d9d6cf 100644
--- a/pandas/core/internals/construction.py
+++ b/pandas/core/internals/construction.py
@@ -369,7 +369,7 @@ def extract_index(data) -> Index:
         index = Index([])
     elif len(data) > 0:
         raw_lengths = []
-        indexes: List[Any] = []
+        indexes: List[Union[List[Label], Index]] = []
 
         have_raw_arrays = False
         have_series = False

From bcd0257af220a2ebc66e1759eb756be65c75adef Mon Sep 17 00:00:00 2001
From: Richard Shadrach <rhshadrach@gmail.com>
Date: Mon, 23 Nov 2020 10:42:16 -0500
Subject: [PATCH 7/7] Revert quote removal from pandas.core.generic

---
 pandas/core/dtypes/generic.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/pandas/core/dtypes/generic.py b/pandas/core/dtypes/generic.py
index daf205237a42e..34891180906bb 100644
--- a/pandas/core/dtypes/generic.py
+++ b/pandas/core/dtypes/generic.py
@@ -4,7 +4,8 @@
 from typing import TYPE_CHECKING, Type, cast
 
 if TYPE_CHECKING:
-    from pandas import DataFrame, NDFrame, Series
+    from pandas import DataFrame, Series
+    from pandas.core.generic import NDFrame
 
 
 # define abstract base classes to enable isinstance type checking on our
@@ -60,15 +61,15 @@ def _check(cls, inst) -> bool:
 )
 
 ABCNDFrame = cast(
-    Type[NDFrame],
+    "Type[NDFrame]",
     create_pandas_abc_type("ABCNDFrame", "_typ", ("series", "dataframe")),
 )
 ABCSeries = cast(
-    Type[Series],
+    "Type[Series]",
     create_pandas_abc_type("ABCSeries", "_typ", ("series",)),
 )
 ABCDataFrame = cast(
-    Type[DataFrame], create_pandas_abc_type("ABCDataFrame", "_typ", ("dataframe",))
+    "Type[DataFrame]", create_pandas_abc_type("ABCDataFrame", "_typ", ("dataframe",))
 )
 
 ABCCategorical = create_pandas_abc_type("ABCCategorical", "_typ", ("categorical"))