Yeah sure, there's nothing preventing you from using "constexpr" so it's compile-time evaluated and inlined:

(Please no more macros, it's 202- I mean, 2023!)

  static constexpr bool DEBUG = true;

  [[demo::invariant]] [[gnu::used]]
  void check_invariants()
  {
    if constexpr (!DEBUG) return;

    assert(top >= 0 && top <= MAX_SIZE);
  }