Proposed resolution (November, 2013): Change 9.2.6 [dcl.constexpr] paragraph 8 as follows:
The constexpr specifier has no effect on the type of a
constexpr function or a constexpr
constructor.
The class of which a constexpr
function is a member shall be a literal type
(6.9 [basic.types]). [Example:...
[Applied to WP at the February, 2014 meeting.] The current wording of 9.2.6 [dcl.constexpr] paragraph 8 is: The previous version of this wording made clear that the restriction
on the class type applied only to non-static member functions;
consequently, the new formulation has inadvertently banned static
constexpr member functions of non-literal classes.
The constexpr specifier has no effect on the type of
a constexpr function or a constexpr constructor. The
class of which a constexpr function is a member shall be a literal
type (6.9 [basic.types]).