anchor.diff:             " return for ~w~s on line ~w is ~s\n",
              [M, F, Contract, F, ArgStrings, Line, CRet]);
   message_to_string({invalid_contract, [M, F, A, Sig]}) ->
  -    format("Invalid type specification for function ~w:~w/~w."
  -           " The success typing is ~s\n", [M, F, A, Sig]);
  +    format(?BW "Invalid type specification for function" ?R " ~w:~w/~w."
  +           ?BW " The success typing is" ?R " ~s\n", [M, F, A, Sig]);
   message_to_string({extra_range, [M, F, A, ExtraRanges, SigRange]}) ->
       format("The specification for ~w:~w/~w states that the function"
              " might also return ~s but the inferred return is ~s\n",
  
positive.code: message_to_string({no_return, [Type|Name]}) ->
      NameString =
          case Name of
              [] -> "The created fun ";
              [F, A] -> format("Function ~w/~w ", [F, A])
          end,
      case Type of
          no_match -> NameString ++ "has no clauses that will ever match\n";
          only_explicit -> NameString ++ "only terminates with explicit exception\n";
          only_normal -> NameString ++ "has no local return\n";
          both -> NameString ++ "has no local return\n"
      end;
  message_to_string({record_constr, [RecConstr, FieldDiffs]}) ->
      format("Record construction ~s violates the"
  
negative.code:             case (ArgNs =:= []) orelse IsOverloaded of
                  true ->
                      %% We do not know which arguments caused the failure
                      format(?BW "breaks the contract"?R" ~s\n", [Contract]);
                  false ->
                      format(?BW "breaks the contract"?R" ~s "?BW"in the"?R
                             " ~s "?BW"argument\n",
                             [good_arg(ArgNs, Contract), PositionString])
              end;
          both ->
              format(?BW "will never return since the success typing is "
                     ?R"~s "?BW"->"?R" ~s " ?BW"and the contract is "?R"~s\n",
                     [good_arg(ArgNs, SigArgs), SigRet,
                      good_arg(ArgNs, Contract)])
      end.
  
  form_positions(ArgNs) ->
  