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kotlinlang

is there any difference between the below function signatures -
```fun <T, K, M : MutableMap<in K, in T>> Iterable<T>.associateByTo(destination: M, keySelector: (T) -> K): M ```
&
```fun <T, K> Iterable<T>.associateByTo(destination: MutableMap<in K, in T>, keySelector: (T) -> K): MutableMap<in K, in T>```

The 2nd tells you that it returns the *same exact* map type that you gave in. Thus, if you pass in a HashMap, you get a HashMap and vice verse

[slightly edited the 2nd example to change the return type from Map to MutableMap to make the signatures more equivalent]

i assume you meant `1st` returns the same exact type which makes sense (since it returns `M`).

Sorry yes typo. The 1st basically tells you that, unless there's reflection trickery going on, the return value will always be `destination`, as in the same exact reference