don't print additional error message in argument list evaluation * pt-arg-list.cc (tree_argument_list::convert_to_const_vector): Don't call error for for failed argument evaluation.

# fA.m
function y = fA (x, f)
  global gfun
  if nargin < 2
    y = fA (x, gfun);
  else
    w = feval (f, x);
    y = feval (@fB, w);
  endif
endfunction