A lot of classic c++isms, some good ones. constexpr weirdness is among my top choices
You are expected to watch most of the video, before learning that the purpose of the video is to argue that in almost all cases one should use "static constexpr" and not just "constexpr".
The argumentation can be interesting, but it would have been nicer to just state the conclusion from the beginning, allowing a decision of whether it is desirable to spend time to also know the reasons for this.
In D, CTFE (Compile Time Function Evaluation) is guaranteed to run at compile time. CTFE happens whenever there's a constant-expression in the grammar, such as the initialization of an enum:
enum A = func(3);
Also, constexpr on a variable is not a hint - it must be evaluated at compile time, where-as a constexpr function will be evaluated at either compile time or runtime depending on the context and arguments passed to it. For a function that you either want to work at compile time or not at all (compile error), consteval is the hardened version.
Yes, sadly this means "constexpr" variables and "consteval" functions must be calculated at compile time, while "constexpr" functions can be used both at compile time and runtime. An annoying distinction.
Simply no need for tagging them one way or another.