BUG: add cases to coerce_to_target_dtype

Author: arw2019

pandas/core/internals/blocks.py

@@ -1130,7 +1130,10 @@ def coerce_to_target_dtype(self, other):
         if is_dtype_equal(self.dtype, dtype):
             return self
 
-        if self.is_bool or is_object_dtype(dtype) or is_bool_dtype(dtype):
+        if is_extension_array_dtype(self.dtype) and not is_categorical_dtype(dtype):
+            dtype = self.dtype
+
+        elif self.is_bool or is_object_dtype(dtype) or is_bool_dtype(dtype):
             # we don't upcast to bool
             return self.astype(object)
 
@@ -1174,6 +1177,9 @@ def coerce_to_target_dtype(self, other):
                 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)
         except (ValueError, TypeError, OverflowError):