I realized that my proposed C++11 update for base_from_member should propagate noexcept. But how do I manually specify the noexcept status of an inner constructor? (Beta versions of C++11 may just have core language changes but not the library changes, so I shouldn't rely on is_nothrow_XXX_constructible just like not relying on std::forward.) I originally thought of: class MyType{ MyInnerType x;public: MyType() noexcept( noexcept(MyInnerType()) );}; This expression includes the inner default constructor call, but it also secretly includes a destructor call (for MyInnerType), and therefore includes it in the calculations! But how about: class MyType2{ MyInnerType x;public: MyType2() noexcept( noexcept(new (std::nothrow) MyInnerType()) );}; Hopefully this, or something like it, includes the constructor call, without calling a destructor. I think the C++11 version of nothrow_t-new is marked noexcept, and I hope the complete new call doesn't hide the constructor call. Daryle W.