It throws the parser into an infinite recursion, and results is rather cryptic error messages. It's not high priority, but if anyone knows his way around that thing, it might be worth checking for this.
Sounds like you've triggered a bug in the polymorphic function overloader (cf Tools.Standalone.precompile):
| POLYMORPHIC FUNCTION OVERLOADING | You can define the same function several times with different | types. This program will select the proper function whenever | possible.
Do you have an example?