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kotlinlang

Hi, small question. Is there a way to pattern match a lambda that receives a Map&lt;K,V&gt;. For example:
```onSomething { (key,value) : Map&lt;K,V&gt; -&gt; ... } ```

It's not a pattern match, it's just destructuration:
```mapOf(
    "1" to 1,
    "2" to 2,
).forEach { (key, value) -&gt;
    println("$key → $value")
}```
Pattern matching implies some kind of conditional, it's not the case in Kotlin

It also works with regular for loops:

```val map = mapOf(…)

for ((key, value) in map) {
    …
}```
<https://kotlinlang.org/docs/destructuring-declarations.html>

Yes, I thought that should work
```Destructuring declaration initializer of type Map&lt;String, Boolean&gt;! must have a 'component2()' function```

Ah, you have the wrong `Map` , you're using `java.util.Map` but you should be using `kotlin.Map`

The `!` in the type is a platform type (<https://kotlinlang.org/docs/java-to-kotlin-nullability-guide.html#platform-types>), it means you're using a type that comes from some other language (in your case, Java) which has missing information

I thing the case is that this is a Map&lt;K, out V&gt;

damn, I cannot change it since it cames from a library :sweat_smile:

You should be able to cast it, the Kotlin Map is an alias for the Java one

by manually casting it you tell the compiler that you yourself have checked for nullability

In destructuring-declarations I found the following that worked:
```aMap.mapValues { (aMapKey, aMapValue) -&gt;
    ...
}```


Yeah you were actually trying to destructure the map itself instead of individual entries, that was your issue