http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45923
Ben Longbons <b.r.longbons at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |b.r.longbons at gmail dot | |com --- Comment #13 from Ben Longbons <b.r.longbons at gmail dot com> 2011-07-05 03:52:15 UTC --- Also it seems the destructor must be defaulted. I thought (incorrectly) that only constructors mattered, so tried: protected: ~Base() {} which yields for members: error: enclosing class of '...' is not a literal type and for nonmembers: error: invalid return type 'Derived' of constexpr function '...' but this works: protected: ~Base() = default; specifically, a 'literal type' requires literal members and bases and: * a trivial default constructor or at least one constexpr constructor besides the copy/move constructors (3.9 #10). * a trivial destructor: non-virtual, non-deleted, non-user-provided (12.4 #3)