Virtual methods

[Walter Bright]

Sorry, I had missed the Leaf node.

bearophile wrote:
> With LDC you can use a level of optimization (LTO) that spans all the
> modules you are compiling at once.

That's not safe because there are always opaque modules that are binary 
only. They may derive from the class in the module - and the optimizer 
cannot prove they don't.

Hardly any programmers are knowledgeable enough about compiler 
optimizations to be comfortable using unsafe optimizations correctly. 
Most of the time, you just get mad users and and a reputation for a 
"buggy" optimizer.