fc-solve | Freecell Solver - a C library | Game Engine library

It's a false positive in the sense that cppcheck thinks that an API called erase on an iterator invalidates the iterator. That's the rule that it uses, because that's a sensible API.

Then for this code, it seems to be valid to do ++it because of this:

This is implemented by making erase() not resize the hashtable. If you desire maximum space efficiency, you can call resize(0) after a string of erase() calls, to force the hashtable to resize to the smallest possible size.

This seems to mean that the iterators may encounter deleted objects if you don't call resize(0) between erasures. Here it's fine because erasures are done in the same loop.

The fact that this code hides its behavior by not making it obvious and doesn't use standard patterns doesn't help.