const-assert

Assert is used to create generic trait bounds:

#![allow(incomplete_features)]
#![feature(generic_const_exprs)]

use const_assert::{Assert, IsTrue, IsFalse};

struct Buffer<const N: usize> {
  inner: [usize; N],
}

impl<const N: usize> Buffer<N>
where
  Assert<{ N == N.next_power_of_two() }>: IsTrue,
  Assert<{ N == 1 }>: IsFalse
{
  pub const fn new() -> Self {
      Buffer { inner: [0; N] }
  }
}

static BUFFER: Buffer<1024> = Buffer::new();