[Vm-dev] I really don't understand why this doesn't crash

Hi guys. I would really appreciate if someone could explain me the following. I have this class:

Object subclass: #FooClass instanceVariableNames: 'var1 var2 var3 var4 var5' classVariableNames: '' poolDictionaries: '' category: 'Prueba'

With this method:

FooClass >> foo Transcript show: var5 asString.

And then I have this class:

Object subclass: #AnotherClass instanceVariableNames: 'age' classVariableNames: '' poolDictionaries: '' category: 'Prueba'

Now, I run this test:

| inst | inst := AnotherClass new. inst age: 42. (FooClass >> #foo) valueWithReceiver: inst arguments: #()

So...I am evaluating the CompiledMethod installed on #foo on "inst". The compiledMethod has a bytecode (04) for accessing the var5. But "inst" only have one instVar. So....shouldn't that be a crash? because the VM is accessing outside the object... so, the test doesn't crash and in fact, it prints "1". I don't know what number means.

I took a look to

StackInterpreter >> pushReceiverVariable: fieldIndex

self internalPush: (objectMemory fetchPointer: fieldIndex ofObject: self receiver).

But I guess that should crash.

Thanks for any tip,