In addition to the standard `+` operator, should t...

# language-proposals

[Derek Peirce]

In addition to the standard + operator, should there be a way to implement a more efficient multi-plus method? Such as operator fun <E> Set<E>.plusAll(vararg others: Iterable<E>): Set<E>? Currently, setA + setB + setC will first create an intermediate setAB set, so one must use something like:

buildSet {
    addAll(setA)
    addAll(setB)
    addAll(setC)
}

to avoid the inefficiency, which is a fair bit more code to achieve the same result.