Set.
Operations like 'minus' or 'intersect' are more effective when their argument is a set.
An explicit conversion of an Iterable<T> or an Array<T>
into a Set<T> can often make code more effective.
The quick-fix adds an explicit conversion to the function call.
Example:
fun <T> f(a: Iterable<T>, b: Iterable<T>): Int =
a.intersect(b).size
After the quick-fix is applied:
fun <T> f(a: Iterable<T>, b: Iterable<T>): Int =
a.intersect(b.toSet()).size