strip multiplication factor when recursively folding empty sequences

diff --git a/Cython/Compiler/Optimize.py b/Cython/Compiler/Optimize.py
index 1393232..9292a2c 100644 (file)
--- a/Cython/Compiler/Optimize.py
+++ b/Cython/Compiler/Optimize.py
@@ -3277,8 +3277,8 @@ class ConstantFolding(Visitor.VisitorTransform, SkipDeclarations):
         if factor.constant_result != 1 and sequence_node.args:
             if isinstance(factor.constant_result, (int, long)) and factor.constant_result <= 0:
                 del sequence_node.args[:]
-            else:
-                sequence_node.mult_factor = factor
+                factor = None
+            sequence_node.mult_factor = factor
         return sequence_node
 
     def visit_PrimaryCmpNode(self, node):