Disable some concept checks in C++11

[François Dumont]

On 02/03/2017 06:52, Jonathan Wakely wrote:
> On 27 February 2017 at 20:11, François Dumont wrote:
>> Hi
>>
>>
>>      I had some problems when testing pretty printers while having activated
>> concept checks. I noticed that std::deque had already the
>> _SGIAssignableConcept check disable when using C++11 so I propose to
>> generalize to all usages of this concept check.
> The use in <ext/slist> seems to still be valid, that type wasn't
> updated for C++11 and move semantics, so the original concept checks
> still apply, don't they?

I start wondering if this concept check is not too strict. And also why 
C++11 move semantic would make this concept check useless.

It checks for both valid copy constructor and assignment operator. As 
far as I know containers never use copy assignment operator and never 
did. So why checking for its availability ?

Maybe we should just replace it with _CopyConstructibleConcept which is 
indeed required. We could keep current check in pedantic mode.

François