I'm trying to write a function that accepts a generic Collection and a single element, then returns the index or indices of this element as an array. However, I'm getting an error at the return statement.
func findAll<T: Collection, U: Equatable>(_ items: T, _ find: U) -> [U] where T.Iterator.Element == U {
var found = [Int]()
for (index, item) in items.enumerated() {
if item == find {
found.append(index)
}
}
return found
}