Symfony2 Controller won't catch exception

The following scenario is given, to be interpreted as C++0x code:

struct B { }; 
struct A { B b; }; 
int main() { 
  B const& b = A().b; 
  /* is the object still alive here? */
}

Clang and GCC (trunk version as of 2011/02) behave differently: Clang lengthens the lifetime. GCC moves B to a new temporary object, and then binds the reference to that new temporary.

I cannot find either behavior can be derived from the words of the Standard. The expression A().b is not a temporary (see 5.2.5). Can anyone please explain the following to me?

• Desired behavior (the intent of the committee)
• The behavior as you derive it from the FDIS

Thanks!