# It is memory-efficient but relies on `has` so may be CPU-inefficient for some kind of collections.
fun has_all(other: Collection[nullable Object]): Bool
do
+ if is_same_instance(other) then return true
+ var ol = other.length
+ var l = length
+ if ol == 0 then return true
+ if l == 0 then return false
+ if ol == 1 then return has(other.first)
for x in other do if not has(x) then return false
return true
end