kotlin-types-value-class

Use Kotlin value classes instead of data classes for single-field domain types to prevent primitive misuse and reduce runtime overhead. Value classes provide better type safety without the allocation cost of standard wrapper classes.

To fix unstable parameter warnings in Jetpack Compose, use @JvmInline value classes wrapping stable primitives or Strings. This ensures Compose treats the parameters as stable, reducing unnecessary recompositions at UI boundaries.

@JvmInline value classes avoid boxing overhead by unboxing to underlying primitives at runtime, unlike data classes which allocate objects. Choose value classes for single-field domain wrappers, but note they have different equality and serialization semantics.

Convert a single-field wrapper data class to an @JvmInline value class by annotating it with @JvmInline and the value modifier. This ensures the compiler inlines the underlying type, preventing primitive misuse while maintaining domain meaning.

Limitations of Kotlin value classes include breaking expected equality and serialization semantics if not handled carefully. You should not use them for multi-field types or when domain logic requires reference equality and standard object allocation behaviors.

Yes, you need @JvmInline for Kotlin value classes to ensure unboxing rules apply and prevent boxing overhead in hot paths. Missing @JvmInline loses the performance benefits and may not resolve Compose stability expectations as intended.