anchor.diff:  merge_regs_1([{R1,_}|_]=Rs1, [{R2,_}|Rs2]) when R1 > R2 ->
       merge_regs_1(Rs1, Rs2);
   merge_regs_1([{R,Type1}|Rs1], [{R,Type2}|Rs2]) ->
  -    [{R,merge_types(Type1, Type2)}|merge_regs_1(Rs1, Rs2)];
  +    [{R,join(Type1, Type2)}|merge_regs_1(Rs1, Rs2)];
   merge_regs_1([], []) -> [];
   merge_regs_1([], [_|_]) -> [];
   merge_regs_1([_|_], []) -> [].
  
positive.code:     Vst;
  
  %% Other test instructions.
  valfun_4({test,is_float,{f,Lbl},[Float]}, Vst) ->
      assert_term(Float, Vst),
      set_type({float,[]}, Float, branch_state(Lbl, Vst));
  
negative.code:     Ft = index_parameter_types(Fs, []),
      validate_0(Module, Fs, Ft).
  
  validate_0(_Module, [], _) -> [];
  validate_0(Module, [{function,Name,Ar,Entry,Code}|Fs], Ft) ->
      try validate_1(Code, Name, Ar, Entry, Ft) of
  