diff --git a/pandas/core/groupby/grouper.py b/pandas/core/groupby/grouper.py
index fc914831b7a72..4703c12db602d 100644
--- a/pandas/core/groupby/grouper.py
+++ b/pandas/core/groupby/grouper.py
@@ -330,7 +330,6 @@ def _get_grouper(
 
         return grouper, obj
 
-    @final
     def _set_grouper(
         self, obj: NDFrameT, sort: bool = False, *, gpr_index: Index | None = None
     ) -> tuple[NDFrameT, Index, npt.NDArray[np.intp] | None]:
diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index b559d8bfc1a66..3831af23dc16e 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -49,6 +49,7 @@
     ResamplerWindowApply,
     warn_alias_replacement,
 )
+from pandas.core.arrays import ArrowExtensionArray
 from pandas.core.base import (
     PandasObject,
     SelectionMixin,
@@ -2500,14 +2501,15 @@ def _get_period_bins(self, ax: PeriodIndex):
 
         return binner, bins, labels
 
-    @final
     def _set_grouper(
         self, obj: NDFrameT, sort: bool = False, *, gpr_index: Index | None = None
     ) -> tuple[NDFrameT, Index, npt.NDArray[np.intp] | None]:
         obj, ax, indexer = super()._set_grouper(obj, sort, gpr_index=gpr_index)
         if isinstance(ax.dtype, ArrowDtype) and ax.dtype.kind in "Mm":
             self._arrow_dtype = ax.dtype
-            ax = Index(ax.array._maybe_convert_datelike_array())
+            ax = Index(
+                cast(ArrowExtensionArray, ax.array)._maybe_convert_datelike_array()
+            )
         return obj, ax, indexer