How mutable is immutable?

[Malte Skarupke]

The issue is that you're thinking as you would in Java.

I guess the rule in D for immutable is this: Immutable data won't 
change as long as it exists.

The last part of that sentence would be a stupid thing to say in 
Java because things don't just cease to exist while you're still 
doing something with them. That is not the case in D.

That being said it's very unlikely that you will ever run into 
this situation. You have to end the lifetime of the object 
manually to run into these issues. And in that case it'll be very 
easy to figure out what's wrong.