class Impl1(impl2: Impl2) : SomeInterface by impl2

is

if( myvar is MyObject? )

?

SomeClass

object

objOfSomeClass::class.safeCast(otherInstance) != null

it::class.isInstance(value.type)

kotlin-reflect

zip

T

T

T

class Tree<T>{
  fun getNode(name: String): Tree<T>
}

class Builder<T>{
  fun setNode(name: String, tree: Tree<T>)
}

something: T

in

Type parameter T is declared as 'out' but occurs in 'in' position in type T

override fun receive(t: T) {

java.lang.NullPointerException`

at com.google.api.client.repackaged.com.google.common.base.Preconditions.checkNotNull(Preconditions.java:213)

at com.google.api.client.util.Preconditions.checkNotNull(Preconditions.java:127)

if (!(raw instanceof Map)) {
    ...
}

if (raw !is Map<*, *>) {
   ...
}

raw

LinkedHashTreeMap

Map

readStuff {
    println(it)
}
// Do other things meanwhile...

class Foo(val bar: Bar)
var foo: Foo? = null 
foo?.bar!! // will crash when foo is null 💀