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kotlinlang

```open class A(
    open val a: Int,
    val b: String = "Something"
)

data class B(
    override val a: Int = 20,
    val c: Int = 30
) : A(a)```
I have a composable which is dependant upon `class B`.
```@Composable
fun BCard(b: B) {
    // Compose something
}```
`BCard` recomposes when `a` nad `c` are changed, but not when `b` is changed. How can I solve this?

I'm not sure i get what you are asking here.  Your composable depends on an instance of B, so if that's a state value, the card will recompose when you re-assign it:

```val b = remember { mutableStateOf(B()) }

BCard(b)```
and then at some later point in an onClick callback or something:

```b.value = b.value.copy(a = 50)```
That should trigger recomposition of your card.