docs: @Nonnull
      public BugInstance addOptionalLocalVariable(DismantleBytecode dbc, OpcodeStack.Item item) {
          int register = item.getRegisterNumber();
  
          if (register >= 0) {
              this.add(LocalVariableAnnotation.getLocalVariableAnnotation(dbc.getMethod(), register, dbc.getPC() - 1, dbc.getPC()));
          }
          return this;
      }