@interface AClass : NSObject
+ (instancetype)hoge;
@end

@interface BClass : AClass
@end

@implementation AClass
+ (instancetype)hoge {
    return [self new];
}
@end

@implementation BClass
@end


id objA = [A hoge];    // AClass's instance
id objB = [B hoge];    // BClass's instance

このクラスをSwiftで書き換えることは出来ますか?