Add datetime.date and datetime.datetime specializations (pandas-dev#1003)

* Add datetime.date and datetime.datetime specializations

* Add tests and update overload order

* Don't remove the correct type

* Ignore overload errors

microsoft/pylance-release#6512

Author: alippai

pandas-stubs/_libs/tslibs/offsets.pyi

@@ -14,6 +14,7 @@ from typing import (
 
 from dateutil.relativedelta import weekday as WeekdayClass
 import numpy as np
+from pandas import Timestamp
 from pandas.core.indexes.datetimes import DatetimeIndex
 from typing_extensions import Self
 
@@ -22,7 +23,7 @@ from pandas._typing import npt
 
 from pandas.tseries.holiday import AbstractHolidayCalendar
 
-_DatetimeT = TypeVar("_DatetimeT", bound=date)
+_DatetimeT = TypeVar("_DatetimeT", bound=datetime)
 _TimedeltaT = TypeVar("_TimedeltaT", bound=timedelta)
 
 prefix_mapping: dict[str, type]
@@ -42,26 +43,32 @@ class BaseOffset:
     @overload
     def __add__(self, other: npt.NDArray[np.object_]) -> npt.NDArray[np.object_]: ...
     @overload
-    def __add__(self, other: BaseOffset) -> Self: ...
+    def __add__(self, other: _DatetimeT) -> _DatetimeT: ...  # type: ignore[overload-overlap]  # pyright: ignore[reportOverlappingOverload]
+    @overload
+    def __add__(self, other: date) -> Timestamp: ...
     @overload
-    def __add__(self, other: _DatetimeT) -> _DatetimeT: ...
+    def __add__(self, other: BaseOffset) -> Self: ...
     @overload
     def __add__(self, other: _TimedeltaT) -> _TimedeltaT: ...
     @overload
     def __radd__(self, other: npt.NDArray[np.object_]) -> npt.NDArray[np.object_]: ...
     @overload
-    def __radd__(self, other: BaseOffset) -> Self: ...
+    def __radd__(self, other: _DatetimeT) -> _DatetimeT: ...  # type: ignore[overload-overlap]  # pyright: ignore[reportOverlappingOverload]
     @overload
-    def __radd__(self, other: _DatetimeT) -> _DatetimeT: ...
+    def __radd__(self, other: date) -> Timestamp: ...
+    @overload
+    def __radd__(self, other: BaseOffset) -> Self: ...
     @overload
     def __radd__(self, other: _TimedeltaT) -> _TimedeltaT: ...
     def __sub__(self, other: BaseOffset) -> Self: ...
     @overload
     def __rsub__(self, other: npt.NDArray[np.object_]) -> npt.NDArray[np.object_]: ...
     @overload
-    def __rsub__(self, other: BaseOffset) -> Self: ...
+    def __rsub__(self, other: _DatetimeT) -> _DatetimeT: ...  # type: ignore[overload-overlap]  # pyright: ignore[reportOverlappingOverload]
     @overload
-    def __rsub__(self, other: _DatetimeT) -> _DatetimeT: ...
+    def __rsub__(self, other: date) -> Timestamp: ...
+    @overload
+    def __rsub__(self, other: BaseOffset) -> Self: ...
     @overload
     def __rsub__(self, other: _TimedeltaT) -> _TimedeltaT: ...
     def __call__(self, other): ...

tests/test_timefuncs.py

@@ -664,8 +664,13 @@ def test_some_offsets() -> None:
         ),
         pd.DatetimeIndex,
     )
-    # GH 224
-    check(assert_type(dt.date.today() - Day(), dt.date), dt.date)
+    # GH 755
+    check(assert_type(dt.date.today() - Day(), pd.Timestamp), pd.Timestamp)
+    check(assert_type(dt.date.today() + Day(), pd.Timestamp), pd.Timestamp)
+    check(assert_type(Day() + dt.date.today(), pd.Timestamp), pd.Timestamp)
+    check(assert_type(dt.datetime.now() - Day(), dt.datetime), dt.datetime)
+    check(assert_type(dt.datetime.now() + Day(), dt.datetime), dt.datetime)
+    check(assert_type(Day() + dt.datetime.now(), dt.datetime), dt.datetime)
     # GH 235
     check(
         assert_type(