const AB c = {a,20, numbers};

[bearophile]

Timon Gehr:

> auto c = AB(a, 20, numbers)         <=>   AB c = {a, 20, numbers};
> 
> auto c = const(AB)(a, 20, numbers)  <=>   const AB c = {a, 20, numbers};

I think your second equivalence is wrong:
const c = AB(a, 20, numbers)  <=>   const AB c = {a, 20, numbers};

Bye,
bearophile