Unexpected length of \r\n

ole · June 17, 2020, 7:38am

The result changes when you import Foundation.

("\r\n").contains("\r") // false
("\r\n").contains("\n") // false

Screen Shot 2020-06-17 at 09.30.47

But:

import Foundation

("\r\n").contains("\r") // true
("\r\n").contains("\n") // true

Screen Shot 2020-06-17 at 09.31.50

(Tested in Xcode 11.5.1, Swift 5.2.4)

This is because String implicitly imports NSString.contains(_:) when you import Foundation, and the compiler prefers this over the generic Sequence.contains(_:) method. And NSString counts UTF-16 code units, not Characters.