Re: using declaration to introduce a name

From:
Victor Bazarov <v.Abazarov@comAcast.net>
Newsgroups:
comp.lang.c++
Date:
Wed, 08 Oct 2008 15:55:00 -0400
Message-ID:
<gcj36j$rrr$1@news.datemas.de>
mzdude wrote:

I have the following code

struct foo
{
   operator std::string () const { return str;}
   std::string f() const {return str;}

   std::string str;
};

struct bar : private foo
{
   using foo::operator std::string;
   using foo::f;
};

void test()
{

   bar b;
   std::string a = b; // Ok
   std::string a2 = b.f(); // Ok

   const bar b2;


Comeau justifiably complains about that declaration/definition, it has
no initialiser. Change it to

      const bar b2(b);

and the code compiles fine.

   std::string a3 = b2; // Compile error
   std::string a4 = b2.f(); // Ok
}

My question is why does the compiler have a problem with the const
for the operator but not the function.


Because of the bug in the compiler, maybe?

Post the same question to 'microsoft.public.vc.language' (you *are*
using MSVC, aren't you?)

error XXXX: 'initializing' : cannot convert from 'const bar' to
 'std::basic_string<_Elem,_Traits,_Ax>'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>,
            _Ax=std::allocator<char>
        ]
        No constructor could take the source type, or constructor
overload resolution was ambiguous


V
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