fix for refnanny C code in dict iteration: generate all GOTREFs before all...

fix for refnanny C code in dict iteration: generate all GOTREFs before all coercions before all assignments to properly handle error cases

Cython/Compiler/Nodes.py

@@ -5370,8 +5370,8 @@ class DictIterationNextNode(Node):
         # evaluate all coercions before the assignments
         for var, result, target in assignments:
             code.put_gotref(var.result())
+        for var, result, target in assignments:
             result.generate_evaluation_code(code)
-
         for var, result, target in assignments:
             target.generate_assignment_code(result, code)
             var.release(code)