Fix .replace(Index, Index) raising a TypeError (#16513)

Since `cudf.Index` is list-like, passing this to `.replace` should act like replacing a list of values with a corresponding list of values.

Discovered while working on rapidsai/cuml#6019

Authors:
  - Matthew Roeschke (https://github.com/mroeschke)

Approvers:
  - GALI PREM SAGAR (https://github.com/galipremsagar)

URL: #16513

python/cudf/cudf/core/indexed_frame.py

@@ -6469,7 +6469,7 @@ def _get_replacement_values_for_columns(
         to_replace_columns = {col: [to_replace] for col in columns_dtype_map}
         values_columns = {col: [value] for col in columns_dtype_map}
     elif cudf.api.types.is_list_like(to_replace) or isinstance(
-        to_replace, ColumnBase
+        to_replace, (ColumnBase, BaseIndex)
     ):
         if is_scalar(value):
             to_replace_columns = {col: to_replace for col in columns_dtype_map}
@@ -6483,7 +6483,9 @@ def _get_replacement_values_for_columns(
                 )
                 for col in columns_dtype_map
             }
-        elif cudf.api.types.is_list_like(value):
+        elif cudf.api.types.is_list_like(
+            value
+        ) or cudf.utils.dtypes.is_column_like(value):
             if len(to_replace) != len(value):
                 raise ValueError(
                     f"Replacement lists must be "
@@ -6495,9 +6497,6 @@ def _get_replacement_values_for_columns(
                     col: to_replace for col in columns_dtype_map
                 }
                 values_columns = {col: value for col in columns_dtype_map}
-        elif cudf.utils.dtypes.is_column_like(value):
-            to_replace_columns = {col: to_replace for col in columns_dtype_map}
-            values_columns = {col: value for col in columns_dtype_map}
         else:
             raise TypeError(
                 "value argument must be scalar, list-like or Series"
@@ -6592,12 +6591,13 @@ def _get_replacement_values_for_columns(
     return all_na_columns, to_replace_columns, values_columns
 
 
-def _is_series(obj):
+def _is_series(obj: Any) -> bool:
     """
     Checks if the `obj` is of type `cudf.Series`
     instead of checking for isinstance(obj, cudf.Series)
+    to avoid circular imports.
     """
-    return isinstance(obj, Frame) and obj.ndim == 1 and obj.index is not None
+    return isinstance(obj, IndexedFrame) and obj.ndim == 1
 
 
 @_performance_tracking

python/cudf/cudf/tests/test_replace.py

@@ -1378,3 +1378,9 @@ def test_fillna_nan_and_null():
     result = ser.fillna(2.2)
     expected = cudf.Series([2.2, 2.2, 1.1])
     assert_eq(result, expected)
+
+
+def test_replace_with_index_objects():
+    result = cudf.Series([1, 2]).replace(cudf.Index([1]), cudf.Index([2]))
+    expected = pd.Series([1, 2]).replace(pd.Index([1]), pd.Index([2]))
+    assert_eq(result, expected)