This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 115d. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.
2024-10-26
[Voted into the WP at the February, 2012 meeting; moved to DR at the October, 2012 meeting.]
The current wording appears to allow calling a constexpr function that is never defined within the body of a constexpr function. (The wording was intended to allow mutually-recursive constexpr functions but require that the not-yet-defined function be defined before it would be needed in an actual constant expression.)
Proposed resolution (August, 2011):
Change the indicated bullet of 7.7 [expr.const] paragraph 2 as follows:
an invocation of an undefined constexpr function
or an undefined constexpr constructor outside the definition
of a constexpr function or a constexpr
constructor;