use ExtensionIndex._concat_same_dtype (pandas-dev#32232)

Author: jbrockmendel

pandas/core/indexes/datetimelike.py

@@ -552,14 +552,6 @@ def _summary(self, name=None) -> str:
         result = result.replace("'", "")
         return result
 
-    def _concat_same_dtype(self, to_concat, name):
-        """
-        Concatenate to_concat which has the same class.
-        """
-        new_data = type(self._data)._concat_same_type(to_concat)
-
-        return self._simple_new(new_data, name=name)
-
     def shift(self, periods=1, freq=None):
         """
         Shift index by desired number of time frequency increments.