scala - Type dependent implicits -

two implicits needed in function, can't have them in same parameter list, because dependent method type. considered currying once more, gives me syntax error. what's correct way this?

def add[a](newannotations: seq[a])     (implicit maybeadd: maybeadd[l, seq[a]])     (implicit mod: modifier[maybeadd.out, seq[a], seq[a]]):     slab[content, maybeadd.out] = {   val l = maybeadd(annotations, seq[a]())   l.updatewith(_ ++ newannotations) } 

i edited maybeadd have aux type, suggested @milessabin.

def add[a, out0](newannotations: seq[a])(implicit maybeadd: maybeadd.aux[l, seq[a], out0], mod: modifier[out0, seq[a], seq[a]]): slab[content, mod.out] = {   val l = maybeadd(annotations, seq[a]())   new slab(content, mod(l, _ ++ newannotations)) }