fix leaking communicator (#11)

scripts/errors/coll/Correct.py

@@ -45,14 +45,14 @@ class CorrectColl(ErrorGenerator):
         for func_to_use in self.topology_functions:
             tm = get_collective_template(func_to_use)
             tm.set_description("Correct-" + func_to_use, "Correct code")
+            comm_free = CorrectMPICallFactory().mpi_comm_free()
+            comm_free.set_arg("comm", "&mpi_comm_0")
+            tm.register_instruction(comm_free)
             yield tm
             tm.set_description("Correct-" + func_to_use + "-mpi_cart_get", "Correct code")
             cart_get = CorrectMPICallFactory().mpi_cart_get()
             cart_get.set_arg("comm_cart", "mpi_comm_0")
-            tm.register_instruction(cart_get)
-            comm_free=CorrectMPICallFactory().mpi_comm_free()
-            comm_free.set_arg("comm","&mpi_comm_0")
-            tm.register_instruction(comm_free)
+            tm.insert_instruction(cart_get,before_instruction=comm_free)
             yield tm
             if generate_level <= BASIC_TEST_LEVEL:
                 break