Proposed resolution:

This wording is relative to N4296.

1. Change [c.math] p11 b2 as indicated:

   -11- Moreover, there shall be additional overloads sufficient to ensure:

   1. […]

   2. Otherwise, if any arithmetic argument corresponding to a double parameter has type double or an integer typea type which is not floating-point, but which is implicitly convertible to double, then all arithmetic arguments corresponding to double parameters are effectively cast to double.

   3. […]