From e6cedca6ec2058a9eb08e1b23073119830444ad6 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Sun, 15 Nov 2020 10:30:43 -0800
Subject: [PATCH 1/4] CLN: remove unnecessary no_setting_name setting

---
 pandas/core/indexes/category.py  | 1 -
 pandas/core/indexes/datetimes.py | 2 +-
 pandas/core/indexes/interval.py  | 1 -
 3 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/pandas/core/indexes/category.py b/pandas/core/indexes/category.py
index 06df8f85cded7..4b79ac9faf769 100644
--- a/pandas/core/indexes/category.py
+++ b/pandas/core/indexes/category.py
@@ -224,7 +224,6 @@ def _simple_new(cls, values: Categorical, name: Label = None):
         result._cache = {}
 
         result._reset_identity()
-        result._no_setting_name = False
         return result
 
     # --------------------------------------------------------------------
diff --git a/pandas/core/indexes/datetimes.py b/pandas/core/indexes/datetimes.py
index 9744eb0ecbb88..5d0ecf8f8fe6c 100644
--- a/pandas/core/indexes/datetimes.py
+++ b/pandas/core/indexes/datetimes.py
@@ -327,7 +327,7 @@ def _simple_new(cls, values: DatetimeArray, name: Label = None):
         result._data = values
         result.name = name
         result._cache = {}
-        result._no_setting_name = False
+
         # For groupby perf. See note in indexes/base about _index_data
         result._index_data = values._data
         result._reset_identity()
diff --git a/pandas/core/indexes/interval.py b/pandas/core/indexes/interval.py
index 2aec86c9cdfae..bfbb4a00638fc 100644
--- a/pandas/core/indexes/interval.py
+++ b/pandas/core/indexes/interval.py
@@ -239,7 +239,6 @@ def _simple_new(cls, array: IntervalArray, name: Label = None):
         result._data = array
         result.name = name
         result._cache = {}
-        result._no_setting_name = False
         result._reset_identity()
         return result
 

From ed5a445bec44916b4bfd59592e06c69f0e154a8a Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Sun, 15 Nov 2020 12:20:41 -0800
Subject: [PATCH 2/4] REF: share _simple_new

---
 pandas/core/indexes/base.py         |  2 +-
 pandas/core/indexes/datetimelike.py | 15 +++++++++++++++
 pandas/core/indexes/datetimes.py    | 16 +---------------
 pandas/core/indexes/period.py       | 22 ----------------------
 pandas/core/indexes/timedeltas.py   | 16 +---------------
 5 files changed, 18 insertions(+), 53 deletions(-)

diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index cb5641a74e60b..2e5be63c4bd26 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -418,7 +418,7 @@ def asi8(self):
         return None
 
     @classmethod
-    def _simple_new(cls, values, name: Label = None):
+    def _simple_new(cls, values: np.ndarray, name: Label = None):
         """
         We require that we have a dtype compat for the values. If we are passed
         a non-dtype compat, then coerce using the constructor.
diff --git a/pandas/core/indexes/datetimelike.py b/pandas/core/indexes/datetimelike.py
index 40a6086f69f85..cb76bf43e4184 100644
--- a/pandas/core/indexes/datetimelike.py
+++ b/pandas/core/indexes/datetimelike.py
@@ -100,6 +100,21 @@ class DatetimeIndexOpsMixin(NDArrayBackedExtensionIndex):
     )
     _hasnans = hasnans  # for index / array -agnostic code
 
+    @classmethod
+    def _simple_new(cls, values, name: Label = None):
+        assert isinstance(values, cls.__annotations__["_data"]), type(values)
+
+        result = object.__new__(cls)
+        result._data = values
+        result._name = name
+        result._cache = {}
+
+        # For groupby perf. See note in indexes/base about _index_data
+        result._index_data = values._data
+
+        result._reset_identity()
+        return result
+
     @property
     def _is_all_dates(self) -> bool:
         return True
diff --git a/pandas/core/indexes/datetimes.py b/pandas/core/indexes/datetimes.py
index 5d0ecf8f8fe6c..d84ae4d0803d6 100644
--- a/pandas/core/indexes/datetimes.py
+++ b/pandas/core/indexes/datetimes.py
@@ -14,7 +14,7 @@
     to_offset,
 )
 from pandas._libs.tslibs.offsets import prefix_mapping
-from pandas._typing import DtypeObj, Label
+from pandas._typing import DtypeObj
 from pandas.errors import InvalidIndexError
 from pandas.util._decorators import cache_readonly, doc
 
@@ -319,20 +319,6 @@ def __new__(
         subarr = cls._simple_new(dtarr, name=name)
         return subarr
 
-    @classmethod
-    def _simple_new(cls, values: DatetimeArray, name: Label = None):
-        assert isinstance(values, DatetimeArray), type(values)
-
-        result = object.__new__(cls)
-        result._data = values
-        result.name = name
-        result._cache = {}
-
-        # For groupby perf. See note in indexes/base about _index_data
-        result._index_data = values._data
-        result._reset_identity()
-        return result
-
     # --------------------------------------------------------------------
 
     @cache_readonly
diff --git a/pandas/core/indexes/period.py b/pandas/core/indexes/period.py
index 44c20ad0de848..16ed01f4a75d1 100644
--- a/pandas/core/indexes/period.py
+++ b/pandas/core/indexes/period.py
@@ -244,28 +244,6 @@ def __new__(
 
         return cls._simple_new(data, name=name)
 
-    @classmethod
-    def _simple_new(cls, values: PeriodArray, name: Label = None):
-        """
-        Create a new PeriodIndex.
-
-        Parameters
-        ----------
-        values : PeriodArray
-            Values that can be converted to a PeriodArray without inference
-            or coercion.
-        """
-        assert isinstance(values, PeriodArray), type(values)
-
-        result = object.__new__(cls)
-        result._data = values
-        # For groupby perf. See note in indexes/base about _index_data
-        result._index_data = values._data
-        result.name = name
-        result._cache = {}
-        result._reset_identity()
-        return result
-
     # ------------------------------------------------------------------------
     # Data
 
diff --git a/pandas/core/indexes/timedeltas.py b/pandas/core/indexes/timedeltas.py
index cf5fa4bbb3d75..b42d401c027be 100644
--- a/pandas/core/indexes/timedeltas.py
+++ b/pandas/core/indexes/timedeltas.py
@@ -2,7 +2,7 @@
 
 from pandas._libs import index as libindex, lib
 from pandas._libs.tslibs import Timedelta, to_offset
-from pandas._typing import DtypeObj, Label
+from pandas._typing import DtypeObj
 from pandas.errors import InvalidIndexError
 from pandas.util._decorators import doc
 
@@ -156,20 +156,6 @@ def __new__(
         )
         return cls._simple_new(tdarr, name=name)
 
-    @classmethod
-    def _simple_new(cls, values: TimedeltaArray, name: Label = None):
-        assert isinstance(values, TimedeltaArray)
-
-        result = object.__new__(cls)
-        result._data = values
-        result._name = name
-        result._cache = {}
-        # For groupby perf. See note in indexes/base about _index_data
-        result._index_data = values._data
-
-        result._reset_identity()
-        return result
-
     # -------------------------------------------------------------------
     # Rendering Methods
 

From 0c6e8f7bdb6d95a4a5ecb981ecf258c26e0f502a Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Mon, 16 Nov 2020 08:10:28 -0800
Subject: [PATCH 3/4] remove antipattern

---
 pandas/core/indexes/datetimelike.py | 11 ++++++++---
 pandas/core/indexes/datetimes.py    |  1 +
 pandas/core/indexes/period.py       |  1 +
 pandas/core/indexes/timedeltas.py   |  1 +
 4 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/pandas/core/indexes/datetimelike.py b/pandas/core/indexes/datetimelike.py
index cb76bf43e4184..88383cb7bbb6a 100644
--- a/pandas/core/indexes/datetimelike.py
+++ b/pandas/core/indexes/datetimelike.py
@@ -2,7 +2,7 @@
 Base and utility classes for tseries type pandas objects.
 """
 from datetime import datetime
-from typing import TYPE_CHECKING, Any, List, Optional, Tuple, TypeVar, Union, cast
+from typing import TYPE_CHECKING, Any, List, Optional, Tuple, Type, TypeVar, Union, cast
 
 import numpy as np
 
@@ -88,6 +88,7 @@ class DatetimeIndexOpsMixin(NDArrayBackedExtensionIndex):
 
     _can_hold_strings = False
     _data: Union[DatetimeArray, TimedeltaArray, PeriodArray]
+    _data_cls: Union[Type[DatetimeArray], Type[TimedeltaArray], Type[PeriodArray]]
     freq: Optional[BaseOffset]
     freqstr: Optional[str]
     _resolution_obj: Resolution
@@ -101,8 +102,12 @@ class DatetimeIndexOpsMixin(NDArrayBackedExtensionIndex):
     _hasnans = hasnans  # for index / array -agnostic code
 
     @classmethod
-    def _simple_new(cls, values, name: Label = None):
-        assert isinstance(values, cls.__annotations__["_data"]), type(values)
+    def _simple_new(
+        cls,
+        values: Union[DatetimeArray, TimedeltaArray, PeriodArray],
+        name: Label = None,
+    ):
+        assert isinstance(values, cls._data_cls), type(values)
 
         result = object.__new__(cls)
         result._data = values
diff --git a/pandas/core/indexes/datetimes.py b/pandas/core/indexes/datetimes.py
index d84ae4d0803d6..cb1b8836d973f 100644
--- a/pandas/core/indexes/datetimes.py
+++ b/pandas/core/indexes/datetimes.py
@@ -220,6 +220,7 @@ class DatetimeIndex(DatetimeTimedeltaMixin):
 
     _typ = "datetimeindex"
 
+    _data_cls = DatetimeArray
     _engine_type = libindex.DatetimeEngine
     _supports_partial_string_indexing = True
 
diff --git a/pandas/core/indexes/period.py b/pandas/core/indexes/period.py
index 16ed01f4a75d1..c0a3b95499b3d 100644
--- a/pandas/core/indexes/period.py
+++ b/pandas/core/indexes/period.py
@@ -146,6 +146,7 @@ class PeriodIndex(DatetimeIndexOpsMixin, Int64Index):
     _data: PeriodArray
     freq: BaseOffset
 
+    _data_cls = PeriodArray
     _engine_type = libindex.PeriodEngine
     _supports_partial_string_indexing = True
 
diff --git a/pandas/core/indexes/timedeltas.py b/pandas/core/indexes/timedeltas.py
index b42d401c027be..b6c626197eaf9 100644
--- a/pandas/core/indexes/timedeltas.py
+++ b/pandas/core/indexes/timedeltas.py
@@ -103,6 +103,7 @@ class TimedeltaIndex(DatetimeTimedeltaMixin):
 
     _typ = "timedeltaindex"
 
+    _data_cls = TimedeltaArray
     _engine_type = libindex.TimedeltaEngine
 
     _comparables = ["name", "freq"]

From cbd40199147b82f84efa045d4662615bfba1905a Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Mon, 16 Nov 2020 12:04:49 -0800
Subject: [PATCH 4/4] revert annotation in Index._simple_new

---
 pandas/core/indexes/base.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index 2e5be63c4bd26..cb5641a74e60b 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -418,7 +418,7 @@ def asi8(self):
         return None
 
     @classmethod
-    def _simple_new(cls, values: np.ndarray, name: Label = None):
+    def _simple_new(cls, values, name: Label = None):
         """
         We require that we have a dtype compat for the values. If we are passed
         a non-dtype compat, then coerce using the constructor.