Parameters declared as the alias of a template won't accept the arguments of the same type.

[Tejas]

On Sunday, 1 May 2022 at 03:57:12 UTC, Elfstone wrote:
>     module test;
>
>     struct MatrixImpl(S, size_t M, size_t N)
>     {
>     }
>
> [...]

AFAICT, I'm afraid you'll have to stick to `dot2` 🙁


This DIP I believe does what you want but... It wasn't looked 
upon favorably...

https://github.com/dlang/DIPs/blob/master/DIPs/other/DIP1023.md