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kotlinlang

Just throwing this out there, does anyone think it would be a good idea to include such a function in std-lib:
```
inline infix fun Any?.hash(other: Any?): Int = hashCode() * 31 + other.hashCode()
```
It would simplify writing `hashCode` functions:
```
class ABC&lt;A, B, C&gt;(val a: A, val b: B, val c: C) {
    override fun hashCode() = a hash b hash c
}
```

You could also add some overloads for primitives, but that would quickly explode.

I like the idea, but I’m not sure if this will be used. In my experience 95% of `hashCode` functions I use are from data classes. Also with a good IDE you will just auto generate the `hashCode` function in any case.

That's fair (I disagree about the 95%, but that's probably pretty domain specific)

Any particular reason you dont use `Objects.hash` ?

I would be surprised if varargs arent heavily optimised on both the jvm and js

In any case.. I would heavily prefer a global `hash` with agressive compiler inline and unroll than another `Any?` extension. Just my two cents. Would be shorter to write also

Your implemention would also box any primitives I think

One more argument for doing this is that data classes are effectively useless for library APIs: <https://jakewharton.com/public-api-challenges-in-kotlin/>

You can work around the problem with the `copy` function by providing a custom copy function that calls the generated one, you just need to annotate it with `@Deprecated("", level = DeprecationLevel.HIDDEN)` . I don’t know a workaround for `componentN` except for only adding new properties to the end. That said, I don’t like the fact that kotlin adds `componentN` functions to all data classes automatically. Since they aren’t named, they just pose to much of a risk IMO. Especially when the data class is provided by a library.