[throwaway173738]

The other problem with implicit constexpr is that it can change the timing characteristics of your code depending on whether your input data is known at compile time. And then if you want it to be constexpr you have to troubleshoot why it sometimes isn’t. I think this approach of maximal control in exchange for some foot guns is very much in keeping with C++.

[WalterBright]

In D you don't have to troubleshoot it. The compiler will tell you where the problem is if it can't be evaluated at compile time.

> for some foot guns

There just aren't any with this feature.