[Bug c++/13446] New: gcc uses cast operator when constructing an unnamed instance

[Bug c++/13446] New: gcc uses cast operator when constructing an unnamed instance

[erich_guenther at hotmail dot com]

#define FAILS
/* gcc (GCC) 3.3 20030226 (prerelease) (SuSE Linux)
tst.cpp: In constructor `CB::CB()':
tst.cpp:16: error: `SData::operator CDataAccessor&()' is inaccessible
tst.cpp:46: error: within this context
*/
struct CDataAccessor;

// Data layout only
struct SData
{
	int m_x;
#ifdef FAILS
	operator const CDataAccessor &() const
	{
		return * reinterpret_cast<const CDataAccessor *>(this);
	}
#endif
};

// Accessor class
class CDataAccessor: protected SData
{
public:
	explicit CDataAccessor(int i)
	{
		m_x=i;
	};

	int Getx() const
	{
		return m_x;
	}
};

class CA
{
public:
	CA(int i, const CDataAccessor& x);
};

class CB: public CA
{
public:
	CB():CA(2, CDataAccessor(3))
	{
	};
};


void foo()
{
	CB b;
}

-- 
           Summary: gcc uses cast operator when constructing an unnamed
                    instance
           Product: gcc
           Version: 3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: erich_guenther at hotmail dot com
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: i686-pc-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13446

[Bug c++/13446] [3.3/3.4 regression] gcc uses cast operator when constructing an unnamed instance

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2003-12-19 17:20 -------
Interesting. Here's something smaller: 
------------------------ 
struct S; 
 
struct B { 
    operator const S &() const; 
}; 
 
struct S: protected B { 
    S(int i); 
}; 
 
void f(int, const S&); 
 
void g() 
{ 
  f(2,S(3)); 
} 
--------------------------- 
 
g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -c x.cc 
x.cc: In function `void g()': 
x.cc:4: error: `B::operator const S&() const' is inaccessible 
x.cc:15: error: within this context 
x.cc:15: error: `B' is not an accessible base of `S' 
 
This is a regression in 3.2/3.3/3.4 w.r.t 2.95. 
 
The point is that gcc tries to convert the S(3) temporary to a const 
reference using the conversion operator, rather than directly binding 
the temporary. 
 
W. 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |rejects-valid
   Last reconfirmed|0000-00-00 00:00:00         |2003-12-19 17:20:32
               date|                            |
            Summary|gcc uses cast operator when |[3.3/3.4 regression] gcc
                   |constructing an unnamed     |uses cast operator when
                   |instance                    |constructing an unnamed
                   |                            |instance
   Target Milestone|---                         |3.3.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13446

[Bug c++/13446] [3.3/3.4 regression] gcc uses cast operator when constructing an unnamed instance

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |critical


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13446

[Bug c++/13446] [3.3/3.4 regression] gcc uses cast operator when constructing an unnamed instance

[mmitchel at gcc dot gnu dot org]

------- Additional Comments From mmitchel at gcc dot gnu dot org  2004-01-05 21:20 -------
This is not a bug.

[dcl.init.ref] clearly requires that the conversion operator be chosen because
"S(3)" is not an rvalue.

There are no open issues with the commitee about this behavior, but if you think
that this is a defect in the standard you should raise it with the committee.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13446