[lordnaikon]

Is this what is known as pi or dependent types?

[eddyb]

Yes, but limited to being applied at compile-time, with constant arguments.

Fully general dependent type would allow passing in runtime values, which is significantly harder to type-check and execute

[steveklabnik]

I believe that this initial version is not quite fully pi types; we did have an RFC for those but it was deemed too large to start off with.