1.1 --- a/lemon/arg_parser.cc	Fri Mar 23 16:09:27 2018 +0100
     1.2 +++ b/lemon/arg_parser.cc	Wed Oct 17 19:18:04 2018 +0200
     1.3 @@ -221,9 +221,9 @@
     1.4                                  const std::string &opt)
     1.5    {
     1.6      Opts::iterator o = _opts.find(opt);
     1.7 -    Opts::iterator s = _opts.find(syn);
     1.8      LEMON_ASSERT(o!=_opts.end(), "Unknown option: '"+opt+"'");
     1.9 -    LEMON_ASSERT(s==_opts.end(), "Option already used: '"+syn+"'");
    1.10 +    LEMON_ASSERT(_opts.find(syn)==_opts.end(),
    1.11 +                 "Option already used: '"+syn+"'");
    1.12      ParData p;
    1.13      p.help=opt;
    1.14      p.mandatory=false;