anchor.diff:          tm1, tm2
       in
   
  -    unify 14 tm1 tm2 (NonTrivial (tc "Prims.l_True"));
  +    unify 14 tm1 tm2 Trivial;
   
       Options.__clear_unit_tests();
   
  
positive.code:     BU.print1 "%s ..." (BU.string_of_int i);
      FStar.Main.process_args () |> ignore; //set options
      BU.print2 "Unify %s\nand %s\n" (FStar.Syntax.Print.term_to_string x) (FStar.Syntax.Print.term_to_string y);
      let g = Rel.teq (tcenv()) x y |> Rel.solve_deferred_constraints (tcenv()) in
      guard_eq i g.guard_f g';
      check();
      Options.init()    //reset them; exceptions are fatal, so don't worry about resetting them in case guard_eq fails
  
negative.code:     unify 4 id id' Trivial; //(NonTrivial (pars "True /\ (forall x. True)"));
  
      //alpha equivalence 2
      unify 5 (tc "fun x y -> x")
              (tc "fun a b -> a")
              Trivial;
  