BUG: extension array add values of itself cause cause runtime exception pandas-dev#22478

Author: peterpanmj

pandas/core/ops.py

@@ -1151,7 +1151,7 @@ def dispatch_to_extension_op(op, left, right):
                 new_right = [new_right]
             new_right = list(new_right)
         elif is_extension_array_dtype(right) and type(left) != type(right):
-            new_right = list(new_right)
+            new_right = list(right)
         else:
             new_right = right
 

pandas/tests/extension/integer/test_integer.py

@@ -767,6 +767,14 @@ def test_cross_type_arithmetic():
     tm.assert_series_equal(result, expected)
 
 
+def test_arith_extension_array_values():
+
+    s = pd.Series([1, 2, 3], dtype='Int64')
+    result = s + s.values
+    expected = pd.Series([2, 4, 6], dtype='Int64')
+    tm.assert_series_equal(result, expected)
+
+
 def test_groupby_mean_included():
     df = pd.DataFrame({
         "A": ['a', 'b', 'b'],