Nobody uses C++ modules because they are clumsy to use. D's are easy. Note: anyone is free to copy D's module design. It's the best one out there.
> I'm not sure why forward reference declarations is needed nowadays
The article gives reasons. Although they aren't necessary, they are deleterious to code layout which becomes a slave to the declaration order rather than aesthetic order.
> C++'s constexpr
is still lagging behind D's, after 17 years of development. In D, the garbage collector makes memory allocation in it trivial. Furthermore, only the path taken through a function needs to be CTFE-compatible, the path not taken does not.
> I'm not sure why forward reference declarations is needed nowadays
The article gives reasons. Although they aren't necessary, they are deleterious to code layout which becomes a slave to the declaration order rather than aesthetic order.
> C++'s constexpr
is still lagging behind D's, after 17 years of development. In D, the garbage collector makes memory allocation in it trivial. Furthermore, only the path taken through a function needs to be CTFE-compatible, the path not taken does not.