it may be an error to lt/gt compare a complex number to a complex or …

…C-numeric type, but not to an arbitrary other type

--HG--
extra : transplant_source : %95%EA%C2%9B%7C%D5h%B44%C8%2A%1EO%88%AB%FAP%9C%3B%95

Cython/Compiler/ExprNodes.py

@@ -6728,10 +6728,12 @@ def find_common_type(self, env, op, operand1, common_type=None):
 
         # try to use numeric comparisons where possible
         elif type1.is_complex or type2.is_complex:
-            if op not in ('==', '!='):
+            if op not in ('==', '!=') \
+               and (type1.is_complex or type1.is_numeric) \
+               and (type2.is_complex or type2.is_numeric):
                 error(self.pos, "complex types are unordered")
                 new_common_type = error_type
-            if type1.is_pyobject:
+            elif type1.is_pyobject:
                 new_common_type = type1
             elif type2.is_pyobject:
                 new_common_type = type2