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kotlinlang

the fact that it’s a data class has nothing to do with the fact its properties are mutable or not
from the docs (<https://kotlinlang.org/docs/reference/data-classes.html>):
&gt; All primary constructor parameters need to be marked as val or var

data class just means some functions are automatically generated

of course, it includes `equals()` and `hashCode()`
so you need to figure out how it works with mutability in your case

(only properties declared in the constructor are used in function generation
if you move your value to the body, it’s fine