http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53202
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-05-03 08:30:38 UTC --- For that preprocessed source the difference is in the Bind_simple constructor, for 4.6 it is: Bind_simple<Callable>::Bind_simple(const Callable&) [with Callable = background_hello] (struct Bind_simple * const this, const struct background_hello & callable) { struct tuple * D.5382; struct tuple * D.5383; D.5382 = &this->_M_bound; std::tuple<background_hello>::tuple (D.5382, callable); try { } catch { D.5383 = &this->_M_bound; std::tuple<background_hello>::~tuple (D.5383); } } But for 4.8 it fails to initialise its member _M_bound: Bind_simple<Callable>::Bind_simple(const Callable&) [with Callable = background_hello] (struct Bind_simple * const this, const struct background_hello & callable) { struct tuple * D.6070; try { } catch { D.6070 = &this->_M_bound; std::tuple<background_hello>::~tuple (D.6070); } }