using declaration to introduce a name

[mzdude]

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;
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.


error XXXX: 'initializing' : cannot convert from 'const bar' to
'std::basic_str ing<_Elem,_Trai ts,_Ax>'
with
[
_Elem=char,
_Traits=std::ch ar_traits<char> ,
_Ax=std::alloca tor<char>
]
No constructor could take the source type, or constructor
overload resolution was ambiguous

[Victor Bazarov]

Re: using declaration to introduce a name

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.publ ic.vc.language' (you *are*
using MSVC, aren't you?)

>
>
error XXXX: 'initializing' : cannot convert from 'const bar' to
'std::basic_str ing<_Elem,_Trai ts,_Ax>'
with
[
_Elem=char,
_Traits=std::ch ar_traits<char> ,
_Ax=std::alloca tor<char>
]
No constructor could take the source type, or constructor
overload resolution was ambiguous

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

[mzdude]

Re: using declaration to introduce a name

On Oct 8, 3:55 pm, Victor Bazarov <v.Abaza...@com Acast.netwrote:

>
Because of the bug in the compiler, maybe?
>
Post the same question to 'microsoft.publ ic.vc.language' (you *are*
using MSVC, aren't you?)
>

Yes. I'm using VC8. That's what I wanted to know. Was it a compiler
bug or a definition problem.