How curious. Does the compiler finish and produce an executable that fails, or is the issue during compilation?
What version of Nim are you using to compile and what's your compile target (C, CPP, ObjC, JS)? Since you mention vcc I'm assuming you're on Windows? For reference I'm currently using Nim 1.4.2 on Windows and compiling to C seemed to work okay with `-d:release`. That makes it difficult to help directly as I can't reproduce the issue. When you run the program in it's problem state, does it still fail in the same way if you add a `quit(0)` or `echo` statement right at the start, or just after imports? Just wondering if it's possible to isolate where the issue is occurring in the program, or if it's during in an import, or perhaps even before that in a pre set up phase.
