On 01/11/2023 02:45, Hewill Kang via Std-Proposals wrote:
> Ranges adaptors *do* provide (explicit) operator bool since they all
> derived from ‘view_interface’.

With this precedent, for better or worse, I'd say that the decision has
already been taken, and operator bool() should be added to all
containers. It makes very little sense that

  if (vector)

doesn't compile, but

  if (views::all(vector))

does.

My 2 c,

-- 
Giuseppe D'Angelo