@Override
      public void visitConditionalThrowToInstruction(ConditionalThrowToInstruction instruction, int offset, int nextOffset) {
        if (nextOffset > flow.getSize()) nextOffset = flow.getSize();
        int throwToOffset = instruction.offset;
        boolean assigned = throwToOffset == nextOffset ? !isLeaf(nextOffset) && maybeAssigned[nextOffset] :
                           maybeAssigned[nextOffset];
        maybeAssigned[offset] |= assigned;
      }
@Override
      public void visitConditionalThrowToInstruction(ConditionalThrowToInstruction instruction, int offset, int nextOffset)