ExpressibleByFloatLiteral に適合した型、 Double, Float, CGFloat だけじゃなく、たくさんあるっぽい。 Decimal DispatchQueue.SchedulerTimeType.Stride ImmediateScheduler.SchedulerTimeType.Stride MaterialScalarParameter NSDecimalNumber NSNumber OperationQueue.SchedulerTimeType.Stride RunLoop.SchedulerTimeType.Stride
https://developer.apple.com/documentation/swift/expressiblebyfloatliteral