On Friday, 21 March 2025 02:36:29 Pacific Daylight Time Ville Voutilainen via
Std-Proposals wrote:
> If a compiler writer wanted a facility like this, they would already
> be using it.

And we *have* such a facility. It's #if.

I've been using #ifdef __cpp_lib_concepts for a while, for example. Works
pretty well for a very complex library content, none of which is out-of-line
and overridable.

-- 
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
  Principal Engineer - Intel DCAI Platform & System Engineering