On Wed, Jun 27, 2018 at 6:22 AM, M B via Boost-users <boost-users@lists.boost.org> wrote:

This may be a somewhat newbie question.
This is cross-posted on stack exchange before I found this list.
(https://stackoverflow.com/questions/51062374/different-behavior-with-enable-if-using-clang-and-g)

I've responded over on SO as well, but the problem is that boost::numeric::interval is instantiating

std::complex with a user-defined type, and the standard gives no assurances that this will work.

[complex.numbers]/2 says:

The effect of instantiating the template complex for any type other than float, double, or long double is unspecified.

-- Marshall