func f(_:Bool) {}

struct S {
  func g(_:Int) -> Bool { return true }
  func g(_:Double) -> Bool { return false }
}

let s = S()
let string = "ABC"

s.g(string)
// -> error: cannot invoke 'g' with an argument list of type '(String)'
//    note: overloads for 'g' exist with these partially matching parameter lists: (Int), (Double)
// * Just as I expected.

f(s.g(string))
// -> error: 'g' produces 'Bool', not the expected contextual result type 'Bool'
// * Why isn't it the same as above? --- I believe, at least, 'Bool' is equal to 'Bool'.