<https://blog.kotlin-academy.com/the-beauty-of-kotlin-typing-system-7a2804fe6cf0>

# feed

[marcinmoskala]

https://blog.kotlin-academy.com/the-beauty-of-kotlin-typing-system-7a2804fe6cf0

[SiebelsTim]

The same is true about when: The closest supertype of String, String and Nothing is Nothing?

It should be String, String and Nothing? -> String?, right?

[marcinmoskala]

ow, yes

[Pavlo Liapota]

And in the summary:

Non-nullable type is a supertype of the nullable one

Should be other way around.

[Pavlo Liapota]

When function declares Nothing as a return type, it means that it will throw an error

Not necessary. You can also declare function with Nothing return type and have an infinite loop inside.

[Pavlo Liapota]

When an expression declares Nothing as a return type, everything surely executed after that will be unreachable

I would not say everything here.
If this expression is inside try-catch block, then everything after this block is reachable.
Also continue and break expressions return Nothing too, but only code after them and until loop’s end is unreachable.

[Dico]

@Pavlo Liapota I think the nullable type is a super type of the non null type. You cant assign a null value to a non-null typed variable, thus, the non-null has to be the subtype.

[Dico]

Why would it be the other way around?

[Pavlo Liapota]

Yes, nullable type is a super type and the article in the summary states other way around.

[Dico]

Ok

[marcinmoskala]

Thanks @Pavlo Liapota Good points 🙂