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

[Paolo Carlini]

Matt Austern wrote:

> There are two different issues: does the container type have to be 
> default constructible (yes: it says so in table 65), and do the 
> container elements have to be default constructible (no; 23.1/3 gives 
> the requirements on container elements, and "default constructible" 
> isn't one of them, and implementations go to a great deal of effort to 
> make sure that they don't require it by accident).
>
> If our concept checking code is requiring container elements to be 
> default constructible, that's just a bug.  Probably a very simple one.

Thanks for the clarification. Indeed, we were enforcing a requirement 
for sequences which basically relied on default constructibility for the 
elements.

Paolo.