Swift 2: expression pattern of type 'Bool' cannot match values of type 'Int'

Just two things wrong:

(1) Your cases are boolean expressions, so you want to compare them against true, not n;

(2) You need a default case. So:

func fizzBuzz(n: Int) -> String {
    switch true {
    case n % 3 == 0: print("Fizz")
    case n % 5 == 0: print("Buzz")
    case n % 15 == 0: print("FizzBuzz")
    default: print("Shoot")
    }
    return "\(n)"
}

You can use case let where and check if both match before checking them individually:

func fizzBuzz(n: Int) -> String {
    let result: String
    switch n {
    case let n where n.isMultiple(of: 3) && n.isMultiple(of: 5):
        result = "FizzBuzz"
    case let n where n.isMultiple(of: 3):
        result = "Fizz"
            case let n where n.isMultiple(of: 5):
        result = "Buzz"
    default:
        result = "none"
    }
    print("n:", n, "result:", result)
    return result
}