Remove downcast argument from resample.interpolate (#62866)

Author: phofl

pandas/core/resample.py

@@ -850,7 +850,6 @@ def interpolate(
         inplace: bool = False,
         limit_direction: Literal["forward", "backward", "both"] = "forward",
         limit_area=None,
-        downcast=lib.no_default,
         **kwargs,
     ):
         """
@@ -907,11 +906,6 @@ def interpolate(
               (interpolate).
             * 'outside': Only fill NaNs outside valid values (extrapolate).
 
-        downcast : optional, 'infer' or None, defaults to None
-            Downcast dtypes if possible.
-
-            .. deprecated:: 2.1.0
-
         **kwargs : optional
             Keyword arguments to pass on to the interpolating function.
 
@@ -993,7 +987,6 @@ def interpolate(
         Note that the series correctly decreases between two anchors
         ``07:00:00`` and ``07:00:02``.
         """
-        assert downcast is lib.no_default  # just checking coverage
         result = self._upsample("asfreq")
 
         # If the original data has timestamps which are not aligned with the
@@ -1030,7 +1023,6 @@ def interpolate(
             inplace=inplace,
             limit_direction=limit_direction,
             limit_area=limit_area,
-            downcast=downcast,
             **kwargs,
         )
 

pandas/tests/copy_view/test_interp_fillna.py

@@ -134,7 +134,7 @@ def test_interpolate_object_convert_copies():
     arr_a = get_array(df, "a")
     msg = "Can not interpolate with method=pad"
     with pytest.raises(ValueError, match=msg):
-        df.interpolate(method="pad", inplace=True, downcast="infer")
+        df.interpolate(method="pad", inplace=True)
 
     assert df._mgr._has_no_reference(0)
     assert np.shares_memory(arr_a, get_array(df, "a"))
@@ -148,7 +148,7 @@ def test_interpolate_downcast_reference_triggers_copy():
 
     msg = "Can not interpolate with method=pad"
     with pytest.raises(ValueError, match=msg):
-        df.interpolate(method="pad", inplace=True, downcast="infer")
+        df.interpolate(method="pad", inplace=True)
         assert df._mgr._has_no_reference(0)
         assert not np.shares_memory(arr_a, get_array(df, "a"))