}
	for i := 0; i < n; i++ {
		if xt, targ := in[i].Type(), t.In(i); !xt.AssignableTo(toRType(targ)) {
			panic("reflect: " + op + " using " + xt.String() + " as type " + stringFor(targ))
		}
	}
	if !isSlice && isVariadic {
		// prepare slice for remaining values
		m := len(in) - n
		slice := MakeSlice(toRType(t.In(n)), m, m)
		elem := toRType(t.In(n)).Elem() // FIXME cast to slice type and Elem()
		for i := 0; i < m; i++ {