Protocol requirement cannot be satisfied by a non-final class because it uses 'Self' in a non-parameter, non-result type
swift
Solution
The problem has to do with the indeterminate nature of what would happen if MyClass had a subclass (because generics, such as Array, are not classes and don't magically do polymorphism). Just do what the error message says, and all will be well:
protocol MyProtocol {
static func foo(verticies:[Self]) -> Int
}
final class MyClass : MyProtocol {
class func foo(verticies:[MyClass]) -> Int {
return 1
}
}
Problem
I want to implement a protocol with a class method that takes an array of the implementing class as a parameter. For instance something like this: ``` protocol MyProtocol { static func foo(verticies: [Self]) -> Int } class MyClass : MyProtocol { class func foo(verticies: [MyClass]) -> Int { return 42 } } ``` When I attempt this, I get the following error: Protocol 'MyProtocol' requirement 'foo()' cannot be satisfied by a non-final 'MyClass' class because it uses 'Self' in a non-parameter, non-result type But this works perfectly if I use an object of type MyClass rather than an array: ``` protocol MyProtocol { static func foo(verticies: Self) -> Int } class MyClass : MyProtocol { class func foo(verticies: MyClass) -> Int { return 42 } } ``` Why doesn't this work for an array type, and is there a correct way to do this?