CLN: remove _has_complex_internals

pandas/core/groupby/generic.py

@@ -435,9 +435,6 @@ def _aggregate_named(self, func, *args, **kwargs):
         initialized = False
 
         for name, group in self:
-            # Each step of this loop corresponds to
-            #  libreduction._BaseGrouper._apply_to_group
-            # NB: libreduction does not pin name
             object.__setattr__(group, "name", name)
 
             output = func(group, *args, **kwargs)

pandas/core/indexes/base.py

@@ -4696,14 +4696,6 @@ def _require_scalar(self, value):
             raise TypeError(f"'value' must be a scalar, passed: {type(value).__name__}")
         return value
 
-    @property
-    def _has_complex_internals(self) -> bool:
-        """
-        Indicates if an index is not directly backed by a numpy array
-        """
-        # used to avoid libreduction code paths, which raise or require conversion
-        return False
-
     def _is_memory_usage_qualified(self) -> bool:
         """
         Return a boolean if we need a qualified .info display.

pandas/core/indexes/datetimelike.py

@@ -548,11 +548,6 @@ def _with_freq(self, freq):
         arr = self._data._with_freq(freq)
         return type(self)._simple_new(arr, name=self._name)
 
-    @property
-    def _has_complex_internals(self) -> bool:
-        # used to avoid libreduction code paths, which raise or require conversion
-        return True
-
     def is_type_compatible(self, kind: str) -> bool:
         warnings.warn(
             f"{type(self).__name__}.is_type_compatible is deprecated and will be "

pandas/core/indexes/extension.py

@@ -308,11 +308,6 @@ def _simple_new(
     __truediv__ = _make_wrapped_arith_op("__truediv__")
     __rtruediv__ = _make_wrapped_arith_op("__rtruediv__")
 
-    @property
-    def _has_complex_internals(self) -> bool:
-        # used to avoid libreduction code paths, which raise or require conversion
-        return True
-
     # ---------------------------------------------------------------------
     # NDarray-Like Methods
 

pandas/core/indexes/multi.py

@@ -1543,11 +1543,6 @@ def _get_level_number(self, level) -> int:
                 ) from err
         return level
 
-    @property
-    def _has_complex_internals(self) -> bool:
-        # used to avoid libreduction code paths, which raise or require conversion
-        return True
-
     @cache_readonly
     def is_monotonic_increasing(self) -> bool:
         """