title: constexpr for loop compilation
body: <p>I have read <a href="https://stackoverflow.com/questions/42005229/why-for-loop-isnt-a-compile-time-expression-and-extended-constexpr-allows-for-l">this</a> and  but i still do not know how to make this work with <code>-std=gnu++2a</code>
  I am not sure how to use <a href="https://en.cppreference.com/w/cpp/utility/integer_sequence" rel="nofollow noreferrer">integer seq</a>. Could you please help me with adapting the below code so that it compiles? Thx</p>
  <pre><code>constexpr bool example(const int k)
  {
      return k &lt; 23 ? true: false;
  }
  
  constexpr bool looper()
  {
      constexpr bool result = false;
      for(int k = 0; k &lt; 20; k ++)
      {
          for (int i = 0 ; i &lt; k; ++i)
          {
          constexpr bool result = example(i);
          }
      }
  
      return result;
  }
  
  int main()
  {
      constexpr bool result = looper();
      return 0;
  }
  </code></pre>