text: var $elm$core$List$concat = function (lists) {
    var tmp = _List_Cons(undefined, _List_Nil);
    var end = tmp;
    if (!lists.b) {
      return _List_Nil;
    }
    for (; lists.b.b; lists = lists.b) {
      var xs = lists.a;
      for (; xs.b; xs = xs.b) {
        var next = _List_Cons(xs.a, _List_Nil);
        end.b = next;
        end = next;
      }
    }
    end.b = lists.a;
  
    return tmp.b;
  };
  