src/main/java/com/basistech/tclre/Nfa.java
void moveins(State old, State newState) {
        Arc a;

        assert old != newState;

        while ((a = old.ins) != null) {
            cparc(a, a.from, newState);
            freearc(a);
        }
        assert old.nins == 0;
        assert old.ins == null;
    }
void moveins(State old, State newState) {
        Arc a;

        assert old != newState;

        while ((a = old.ins) != null) {
            cparc(a, a.from, newState);
            freearc(a);
        }
        assert old.nins == 0;
        assert old.ins == null;
    }
moveins - move all in arcs of a state to another state
You might think this could be done better by just updating the
existing arcs, and you would be right if it weren't for the desire
for duplicate suppression, which makes it easier to just make new
ones to exploit the suppression built into newarc.