std::deque<>::_C_insert_1() declared but not defined

[Farid Zaripov <Fa...@epam.com>]

  In include/deque header file the deque<>::_C_insert_1() method is
declared, but not defined.

include/deque, line 684:
---------
// implements a single-element insert
void _C_insert_1 (const iterator&, const_reference);
---------

  This method is never used, so there no problems, but MSVC issues
warning:
warning C4661: 'void std::deque<_>::_C_insert_1(...)' : no suitable
definition provided for explicit template instantiation request
 
Farid.

Re: std::deque<>::_C_insert_1() declared but not defined

[Martin Sebor <se...@roguewave.com>]

Farid Zaripov wrote:
>   In include/deque header file the deque<>::_C_insert_1() method is
> declared, but not defined.
> 
> include/deque, line 684:
> ---------
> // implements a single-element insert
> void _C_insert_1 (const iterator&, const_reference);
> ---------
> 
>   This method is never used, so there no problems, but MSVC issues
> warning:
> warning C4661: 'void std::deque<_>::_C_insert_1(...)' : no suitable
> definition provided for explicit template instantiation request

I think I meant to provide it as an optimization, the same way 
_C_insert_1() is provided in vector but never finished it. We
can probably take it out for now but we should come back to it
in the future. It might be a useful optimization, and our deque
is in need of performance improvement.

Martin