Parameter assigned with default (= default) means? [duplicate]

Answer 1

It doesn't mean anything. What you're seeing is due to a bug in the way the headers are translated into Swift. There is a default value here but you are not being shown what it is.

Another case in point in the headers is the recurring refrain where S.Generator.Element == S.Generator.Element. It's just an erroneous byproduct of the automatic translation process, and has been acknowledged as such by Apple.

Answer 2

Rewrite it as e.g.

func precondition(condition: @autoclosure () -> Bool, _ message: @autoclosure () -> String = "default", file: StaticString = "default", line: UWord = 2)

to make an example to matt's answer