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kotlinlang

I'm working with a collection of data class instances and some of them might share the exact same data. I'd like to put these as keys in a map, but I want each instance to be its own unique key. Is there a way to do this?

Can I create my own subclass of map which uses `Any`'s implementation of `equals` and `hashcode` for the keys even if they are data classes?

I figured out a way to create a simple wrapper class to do this. If anyone is interested:
```class IdentityMap<K, out V> private constructor(
    delegateMap: java.util.TreeMap<K, V>
) : Map<K, V> by delegateMap {
    constructor(
        data: Collection<Pair<K, V>>
    ) : this(
        java.util.TreeMap<K, V>(compareBy(System::identityHashCode)).apply { putAll(data) }
    )
}```

<https://docs.oracle.com/javase/8/docs/api/java/util/IdentityHashMap.html>

There's always one more class I don't know about, it seems.