Protocol for Logger iOS 14

Using Swift
1

Hi! I'm trying to hide new Logger API with protocol, but get runtime error.

protocol MyLogger {
    associatedtype Message: ExpressibleByStringInterpolation where Message.StringLiteralType == String
    func log(_ message: Message)
}

class SomethingWithLogger<L: MyLogger> {
    let logger: L
    init(logger: L) {
        self.logger = logger
    }
    func log() {
        logger.log("log")
    }
}

And try to use it:

extension Logger: MyLogger {
    public typealias Message = OSLogMessage
}

final class LoggerExampleTests: XCTestCase {
    func testLog1() {
        let smthWithLogger = SomethingWithLogger(logger: Logger())
        let logger = smthWithLogger.logger
        logger.log("log")
    }

    func testLog2() {
        let smthWithLogger = SomethingWithLogger(logger: Logger())
        smthWithLogger.log()
    }
}

First test ends with success, but second crashes with EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0). iOS 14 is still in beta so I'm not sure is there bug in my code or somewhere else. if it's my fault - what do I do wrong?