code: @Override
      public void sawOpcode(int seen) {
          boolean sawResource = false;
          try {
              stack.precomputation(this);
  
              if (seen == Const.INVOKEVIRTUAL) {
                  sawResource = processInvokeVirtual();
              } else if (seen == Const.INVOKESPECIAL) {
                  sawResource = processInvokeSpecial();
              }
  
          } finally {
              stack.sawOpcode(this, seen);
              if (sawResource && (stack.getStackDepth() > 0)) {
                  OpcodeStack.Item item = stack.getStackItem(0);
                  item.setUserValue(Boolean.TRUE);
              }
          }
      }
docs: overrides the visitor to look conflated use of resources and files