anchor.diff:      lists_some(F, Args, false).
   
   -spec lists_some(evaluator(A, Return, FailIndicator), [A], FailIndicator) ->
  -                       Return | FailIndicator.
  +                        Return | FailIndicator.
   lists_some(_, [], False) ->
       False;
   lists_some(F, [H | T], False) ->
  
positive.code: is_version_within_constraint(Vsn, {_Pkg, LVsn1, LVsn2, between}) ->
      NVsn = normalize_version(Vsn),
      NVsn >= normalize_version(LVsn1) andalso
         NVsn =< normalize_version(LVsn2);
  is_version_within_constraint(_Vsn, _Pkg) ->
      false.
  
  
negative.code:     %% and need to be fixed
      PkgConstraints = [fix_con(PkgConstraint) ||
                           PkgConstraint <- RawPkgConstraints],
      Info2 =
          case gb_trees:lookup(Pkg, Dom0) of
              {value, Info0} ->
                  case lists:keytake(Vsn, 1, Info0) of
  