Fixes example snippet in OptionSet.swift

[valeriyvan]

Fixes example snippet in OptionSet.swift

[xwu]

Well found, but what you've discovered isn't good! I wonder if it's a known bug. The result should be as indicated in the documentation currently, and I can't clearly see why it's not. For kicks, I rewrote the function verbatim:

extension OptionSet where Element == Self {
  mutating func __remove(_ member: Element) -> Element? {
    let intersectionElements = intersection(member)
    guard !intersectionElements.isEmpty else { return nil }
    subtract(member)
    return intersectionElements
  }
}

var options: ShippingOptions = [.secondDay]
options.remove(.express) // nil

options: ShippingOptions = [.secondDay]
options.__remove(.express) // ShippingOptions(rawValue: 2)

[xwu]

cc @natecook1000 @airspeedswift

[natecook1000]

It looks like that behavior was fixed in 5.3 (#28378), so whether or not you're getting that fix depends on which version of the stdlib your code is hitting.

[xwu]

Phew, I was worried that I was seeing some dynamic dispatch shenanigans here.