I can't have nested sealed classes?

Support
1

This code compiles fine at the top of the file:

sealed class Change {}
data class FilterChange(val name: FilterName): Change()
object SortChange: Change()

But if I put it inside another class, I get errors on lines 2 and 3 saying: Cannot access '<init>': it is private in 'Change'.

What’s the recommended way to nest this group of classes inside another class?

2 Likes
2

It is annoying, but you will need to nest the subclasses inside of the sealed class.

1 Like
3

Not sure what are you talking about. You can.
https://pl.kotl.in/WD7y-ds3N

4

Your example code is what fatjoe79 recommended, but it’s not what I wrote in my original question. I had the subclasses at the same level of the sealed base class (not inside it).

5

Not sure if it’s possible then. Putting the inheriting classes in the top level scope is a special case that is allowed for top level sealed classes. Maybe this could be changed so it works for nested classes as well. You could create a feature request at https://kotl.in/issue

6

It looks like, in the future, sealed classes may be able to have inheritors anywhere in the same module

https://youtrack.jetbrains.com/issue/KT-20423#focus=Comments-27-4196974.0-0

Roman Elizarov: Moreover, we want to lift the restriction on sealed class from a single file to a single module.

Edit: Here’s an issue specifically for what you want to do, and it’s targeted for Kotlin 1.5:
https://youtrack.jetbrains.com/issue/KT-13495