(* This test used to fail because x was used in the wrong context *)
(* Once this was fixed it still did not work since apply is not *)
(* able to solve a goal that ends in a product. *)
-theorem test2: \forall x. x + 4 = 4 + x.
+theorem test2: \forall x. 4 + x = x + 4.
generalize in match 4.
exact plus_comm.
qed.