move is_categorical_dtype()

Author: kotamatsuoka

pandas/core/internals/blocks.py

@@ -1010,10 +1010,8 @@ def coerce_to_target_dtype(self, other):
         if is_dtype_equal(self.dtype, dtype):
             return self
 
-        if (
-            is_extension_array_dtype(self.dtype)
-            and not is_categorical_dtype(self.dtype)
-            and not self.is_datetime
+        if is_extension_array_dtype(self.dtype) and not is_categorical_dtype(
+            self.dtype
         ):
             dtype = self.dtype
 
@@ -1060,6 +1058,8 @@ def coerce_to_target_dtype(self, other):
             raise AssertionError(
                 f"possible recursion in coerce_to_target_dtype: {self} {other}"
             )
+        if is_categorical_dtype(dtype) or self.is_datetime:
+            return self.astype(object)
 
         try:
             return self.astype(dtype)

pandas/tests/series/methods/test_replace.py

@@ -449,5 +449,5 @@ def test_replace_only_one_dictlike_arg(self):
     )
     def test_replace_dtype(self, series, to_replace, expected):
         # GH 33484
-        result = str(series.replace(to_replace).dtype)
+        result = series.replace(to_replace).dtype
         assert expected == result