I fear the havoc widespread use of constexpr meta-programming could wreak on compile speed. A few such declarations have no noticeable impact on compile times, but as the project grows and such declarations start to proliferate, you can easily imagine productivity suffering due to slow compiles.<p>In my opinion, techniques like these fall under the category of &quot;interesting but probably best avoided in production&quot;. Kind of like ray-tracers written with template meta-programming.