Which language futures make D overcompicated?

[Mark]

On Saturday, 10 February 2018 at 12:35:39 UTC, Timon Gehr wrote:
> So as expected, the difference is that for parametrically 
> polymorphic functions, the type T /does not need to be known at 
> compile time/.

According to this definition C++ doesn't support parametric 
polymorphism either, does it? Are there any C-style languages 
that allow that?