Which method runs through a protocol extension: when is a call dispatched dynamically and when statically?

Predict first

What does this print?

protocol Greeter { func hello() -> String }
extension Greeter {
    func hello() -> String { "default hello" }
    func bye() -> String { "default bye" }
}
struct En: Greeter {
    func hello() -> String { "en hello" }
    func bye() -> String { "en bye" }
}
let e = En()
let g: Greeter = En()
print(e.hello(), e.bye())
print(g.hello(), g.bye())
class Animal { func sound() -> String { "..." } }
extension Animal { func kind() -> String { "animal" } }
class Dog: Animal { override func sound() -> String { "woof" } }
let a: Animal = Dog()
print(a.sound(), a.kind())
protocol Shape { var name: String { get } }
extension Shape { var name: String { "shape" } }
struct Sq: Shape { var name: String { "square" } }
struct Ci: Shape {}
func printName<S: Shape>(_ s: S) { print(s.name) }
printName(Sq()); printName(Ci())
class Base: Greeter { }
class Derived: Base { func hello() -> String { "derived hello" } }
let b: Greeter = Derived()
print(b.hello(), Derived().hello())
func viaGeneric<T: Greeter>(_ t: T) -> String { t.hello() + "/" + t.bye() }
print(viaGeneric(En()), viaGeneric(g as! En))

• en hello en bye / en hello default bye / woof animal / square / shape / default hello derived hello / en hello/default bye en hello/default bye
• en hello en bye / en hello en bye / woof animal / square / shape / derived hello derived hello / en hello/en bye en hello/en bye
• en hello en bye / en hello default bye / woof animal / shape / shape / default hello derived hello / en hello/default bye en hello/default bye