newsub $P4, .Sub, _two_of
Leo answered your question, I just wanted to point out that you can now write the above as:
$P4 = newsub _two_of
As Leo said, the call types conflict. In this case we eventually should be able to make IMCC warn you since the sub is declared in the same module, but in other cases, where the called method may not be bound until runtime, we may not know.
I think the problem is more of a high level language problem than an IMCC problem. Eventually the HLL has to track its own symbols and calling conventions and IMCC just has to trust what it gets. IMCC should eventually be _able_ to do compile time loading of bytecodes and check prototypes and declarations, but it should be controlled by the HLL, not the default (I think).
-Melvin