Fix iteration over temporary cypclass values

Cython/Compiler/ExprNodes.py

@@ -2772,7 +2772,14 @@ class IteratorNode(ExprNode):
     def generate_result_code(self, code):
         sequence_type = self.sequence.type
         if sequence_type.is_cyp_class:
-            begin_func = "%s->begin" % self.sequence.result()
+            if self.sequence.is_temp:
+                self.cpp_iterator_cname = code.funcstate.allocate_temp(sequence_type, manage_ref=False)
+                code.putln("%s = %s;" % (self.cpp_iterator_cname, self.sequence.result()))
+                code.put_incref(self.cpp_iterator_cname, sequence_type)
+                begin_func = "%s->begin" % self.cpp_iterator_cname
+            else:
+               begin_func = "%s->begin" % self.sequence.result()
+
             code.putln("%s = %s();" % (self.result(), begin_func))
             return
         elif sequence_type.is_cpp_class:
@@ -2883,7 +2890,10 @@ class IteratorNode(ExprNode):
         if self.reversed:
             code.putln("if (%s < 0) break;" % self.counter_cname)
         if sequence_type.is_cyp_class:
-            end_func = "%s->end" % self.sequence.result()
+            if self.cpp_iterator_cname:
+                end_func = "%s->end" % self.cpp_iterator_cname
+            else:
+                end_func = "%s->end" % self.sequence.result()
             code.putln("if (!(%s != %s())) break;" % (
                             self.result(),
                             end_func))
@@ -2946,6 +2956,8 @@ class IteratorNode(ExprNode):
             code.funcstate.release_temp(self.iter_func_ptr)
             self.iter_func_ptr = None
         if self.cpp_iterator_cname:
+            if self.sequence.type.is_cyp_class:
+                code.put_decref(self.cpp_iterator_cname, self.sequence.type)
             code.funcstate.release_temp(self.cpp_iterator_cname)
         ExprNode.free_temps(self, code)