Imperative template patterns

[monkyyy]

As we all should know, the ast is modified live and the compiler 
never deallocates. This leads to compiler bugs that give glimpses 
behind the veil. Such ~~bugs~~ features I think are actually 
quite valuable when the devs are overly cautious, see them 
disallowing ct io.

Whats the current knowledge of compiler bugs, and how to use 
them? Anyone found any that Im unaware of?