"Effectively, for argument N to work as lit-arg or get-arg, we must require argument N-1 to also be either lit-arg or get-arg. Else it can't function as intended."
>> f: func [a 'b] [probe a probe b]
>> f 'z x
z
x
== ~ ; isotope
>> f 'z +
** Script Error: + expects [char! any-scalar! date! binary!]
for its value1 argument
From Red Gitter.im
"Effectively, for argument N to work as lit-arg or get-arg, we must require argument N-1 to also be either lit-arg or get-arg. Else it can't function as intended."