always wrap for-iterator node in NextNode after analysing it (might have been replaced)

Cython/Compiler/Nodes.py

@@ -5589,10 +5589,8 @@ class ForInStatNode(LoopNode, StatNode):
     def analyse_expressions(self, env):
         self.target = self.target.analyse_target_types(env)
         self.iterator = self.iterator.analyse_expressions(env)
-        if self.item is None:
-            # Hack. Sometimes analyse_declarations not called.
-            import ExprNodes
-            self.item = ExprNodes.NextNode(self.iterator)
+        import ExprNodes
+        self.item = ExprNodes.NextNode(self.iterator)  # must rewrap after analysis
         self.item = self.item.analyse_expressions(env)
         if (self.iterator.type.is_ptr or self.iterator.type.is_array) and \
             self.target.type.assignable_from(self.iterator.type):