[Bug c++/14419] New: Request clarification of ambiguous overload error.

[Bug c++/14419] New: Request clarification of ambiguous overload error.

[alriddoch at zepler dot org]

The attached code gives an ambiguous overload error on line 22, the full text of
which is pasted below. I am not sure whether this is a bug, but it seems strange
to me that gcc things there is ambiguity when multiple conversions are available
if one of the conversions is an exact match for the type required (std::string)
and the other two available (int, and bool) are not really the right type for
the other two constructors which take "const _CharT *" and "_CharT" respectively.

ambiguous_test.cpp: In function `int main()':
ambiguous_test.cpp:22: error: ambiguous overload for 'operator=' in 's2 = a'
/usr/include/c++/3.3.2/bits/basic_string.h:358: error: candidates are: 
   std::basic_string<_CharT, _Traits, _Alloc>& std::basic_string<_CharT, 
   _Traits, _Alloc>::operator=(const std::basic_string<_CharT, _Traits, 
   _Alloc>&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = 
   std::allocator<char>]
/usr/include/c++/3.3.2/bits/basic_string.h:361: error:                 
   std::basic_string<_CharT, _Traits, _Alloc>& std::basic_string<_CharT, 
   _Traits, _Alloc>::operator=(const _CharT*) [with _CharT = char, _Traits = 
   std::char_traits<char>, _Alloc = std::allocator<char>] <near match>
/usr/include/c++/3.3.2/bits/basic_string.h:364: error:                 
   std::basic_string<_CharT, _Traits, _Alloc>& std::basic_string<_CharT, 
   _Traits, _Alloc>::operator=(_CharT) [with _CharT = char, _Traits = 
   std::char_traits<char>, _Alloc = std::allocator<char>]

-- 
           Summary: Request clarification of ambiguous overload error.
           Product: gcc
           Version: 3.3.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: alriddoch at zepler dot org
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i386-redhat-linux
  GCC host triplet: i386-redhat-linux
GCC target triplet: i386-redhat-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14419

[Bug c++/14419] Request clarification of ambiguous overload error.

[alriddoch at zepler dot org]

------- Additional Comments From alriddoch at zepler dot org  2004-03-03 21:53 -------
Created an attachment (id=5857)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=5857&action=view)
Testcase described in body of report


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14419

[Bug c++/14419] Request clarification of ambiguous overload error.

[konqueror at gmx dot de]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |konqueror at gmx dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14419

[Bug libstdc++/14419] Request clarification of ambiguous overload error.

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-03-03 22:30 -------
No this is not a bug as the last match:
/Users/pinskia/fsf-clean-nocheck/lib/gcc/powerpc-apple-darwin7.2.0/3.5.0/../../../../include/c++/
3.5.0/bits/basic_string.h:438: note:                 std::basic_string<_CharT, _Traits, _Alloc>& std::
basic_string<_CharT, _Traits, _Alloc>::operator=(_CharT) [with _CharT = char, _Traits = std::
char_traits<char>, _Alloc = std::allocator<char>]

means that it can go through the conversion from bool to char to get able to call that one and the first 
one matches because it can go through "std::string" so it is ambiguous which one should be picked by 
the compiler.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
          Component|c++                         |libstdc++
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14419

[Bug libstdc++/14419] Request clarification of ambiguous overload error.

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-03-03 22:49 -------
I don't want to close this PR so quickly. I looked at it, too, and the 
point I see is that there is a conversion operator that converts 
the object to something that exactly matches the arguments of one 
of the constructors of std::string. On the other hand, the two other 
cited constructors need an additional conversion from int to char or  
from bool to char. The fact that the first is not taken seems at least 
confusing to me as well, so I'd like that this is settled by citing the 
relevant parts of the standard. 
 
W. 

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14419

[Bug c++/14419] Request clarification of ambiguous overload error.

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|libstdc++                   |c++


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14419

[Bug c++/14419] Request clarification of ambiguous overload error.

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-04-06 01:15 -------
This is a dup of bug 14830 which has a better explaination of why the error is right.

*** This bug has been marked as a duplicate of 14830 ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14419