Google Code-in

We have a few places in the program that cause an instant termination (by calling the fatal() function). A problem is that some of those calls have the same explanation text, which is makes impossible to know where the problem is. Other texts are totally out of context. For example. “Wrong type …” (of what?), “Out of memory” (requesting how much and what for?), “Impossible!” (what is).

Your task is to go over each call to fatal(), analyze what's happening in that situation, and then add a unique code (or come up with something better) that identifies where it happened. We'd also like you to replace those lazy texts with proper explanations that can help the final user understand what the problem is.