libstdc++ not conforming with --enable-concepts-check?

[Paolo Carlini]

Nathan Myers wrote:

>Maybe std::queue shouldn't require DefaultConstructible, but isn't its
>default container std::deque, and shouldn't deque be enforcing it?  
>Why is it failing to do so?
>  
>
Because deque (and vector, and so on...) individually have really 
**minimal**
concept checks, right now. We can endeavour working on this, if we (you?)
consider it a worthy project...

Paolo.