C++ has been gaining constexpr features for years. These have nothing to do with D at all, except in the sense that all languages everywhere influence each other slightly. Certainly constexpr wasn't drawn directly from D.
if constexpr was the obvious logical next step. It has been suggested and proposed for years. Yes people formally proposed static if, which was heavily inspired by D's static if, but that proposal was rejected because it was poorly designed, and C++'s new if constexpr is about as different as it's possible for two compile-time conditional compilation constructs to be.
C++ has been gaining constexpr features for years. These have nothing to do with D at all, except in the sense that all languages everywhere influence each other slightly. Certainly constexpr wasn't drawn directly from D.
if constexpr was the obvious logical next step. It has been suggested and proposed for years. Yes people formally proposed static if, which was heavily inspired by D's static if, but that proposal was rejected because it was poorly designed, and C++'s new if constexpr is about as different as it's possible for two compile-time conditional compilation constructs to be.