BUG: fix DataFrame+DataFrame op with timedelta64 dtype

pandas/core/frame.py

@@ -4827,14 +4827,7 @@ def _arith_op(left, right):
             left, right = ops.fill_binop(left, right, fill_value)
             return func(left, right)
 
-        if this._is_mixed_type or other._is_mixed_type:
-            # iterate over columns
-            return ops.dispatch_to_series(this, other, _arith_op)
-        else:
-            result = _arith_op(this.values, other.values)
-            return self._constructor(result,
-                                     index=new_index, columns=new_columns,
-                                     copy=False)
+        return ops.dispatch_to_series(this, other, _arith_op)
 
     def _combine_match_index(self, other, func, level=None):
         assert isinstance(other, Series)

pandas/core/ops.py

@@ -1794,8 +1794,9 @@ def f(self, other, axis=default_axis, level=None, fill_value=None):
 
         other = _align_method_FRAME(self, other, axis)
 
-        if isinstance(other, ABCDataFrame):  # Another DataFrame
-            return self._combine_frame(other, na_op, fill_value, level)
+        if isinstance(other, ABCDataFrame):
+            # Another DataFrame
+            return self._combine_frame(other, op, fill_value, level)
         elif isinstance(other, ABCSeries):
             return _combine_series_frame(self, other, na_op,
                                          fill_value=fill_value, axis=axis,

pandas/tests/frame/test_arithmetic.py

@@ -299,3 +299,18 @@ def test_df_bool_mul_int(self):
         result = 1 * df
         kinds = result.dtypes.apply(lambda x: x.kind)
         assert (kinds == 'i').all()
+
+    def test_td64_df_add_int_frame(self):
+        # Check that we don't dispatch to numpy implementation, which treats
+        # int64 as m8[ns]
+        tdi = pd.timedelta_range('1', periods=3)
+        df = tdi.to_frame()
+        other = pd.DataFrame([1, 2, 3], index=tdi)  # indexed like `df`
+        with pytest.raises(TypeError):
+            df + other
+        with pytest.raises(TypeError):
+            other + df
+        with pytest.raises(TypeError):
+            df - other
+        with pytest.raises(TypeError):
+            other - df