Swift throwing methods in protocols

gistfile1.md

//: Playground - noun: a place where people can play

class MyError: Error {}

protocol P {
    func throwingFunc() throws -> Int
    func nonThrowingFunc() -> Int
}

class A: P {
    func throwingFunc() -> Int {
        return 5
    }
    
    func nonThrowingFunc() -> Int {
        return 5
    }
}

class B: P {
    func throwingFunc() throws -> Int {
        throw MyError()
    }
    
    func nonThrowingFunc() throws -> Int {
        throw MyError()
    }
}

Swift Compiler Error Group
MyPlayground.playground:20:7: Type 'B' does not conform to protocol 'P'
MyPlayground.playground:7:10: Protocol requires function 'nonThrowingFunc()' with type '() -> Int'; do you want to add a stub?
MyPlayground.playground:25:10: Candidate throws, but protocol does not allow it