I have a question for Sealed classes vs Sealed interfaces. The official doc does not extend much what is the use case for Sealed interface. To me it appears, if you don't have constructor parameter then use interface. But I don't think thats the only use case. Please tell more if I am missing something

I’d go with “Use interface, unless you can’t and you got to use abstract” The exact same principle with choosing an

abstract class

vs an

interface

That boils down to contructor parameter difference only as a real world use case

An interface doesn't have any constructor at all, let alone constructor parameters.

The difference between

sealed interface

and

sealed class

is the same as between

interface

and

abstract class

. For example, a class can implement multiple

sealed interface

but only a single

sealed class

. Etc.

Understood. basically sealed here just add restriction to heirarchies to regular ones and thats all

Yes,

sealed

just means that it cannot be implemented outside the current module. This allows the compiler to know for sure the entire list of implementations, so you don't have to add the

else

in a

when

. Other than that,

sealed interface

are normal interfaces, and

sealed class

are normal

abstract class

.

Ok understood