c++/6375: GCC errouneously chooses operators

c++/6375: GCC errouneously chooses operators

[pthomas]

>Number:         6375
>Category:       c++
>Synopsis:       GCC errouneously chooses operators
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          rejects-legal
>Submitter-Id:   net
>Arrival-Date:   Fri Apr 19 08:56:19 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Philipp Thomas, SuSE Linux Ag
>Release:        3.1 20020415 (prerelease)
>Organization:
>Environment:
suse-linux-gnu
>Description:
Gcc errouneously decides that it has to choose operators
and then rejects the code. Output of g++ -v is:

Reading specs from /usr/lib/gcc-lib/i486-suse-linux/3.1/specs
Configured with: ../configure --enable-threads=posix --prefix=/usr --with-local-prefix=/usr/local --infodir=/u
sr/share/info --mandir=/usr/share/man --enable-languages=c,c++,f77,objc,java,ada --with-gxx-include-dir=/usr/i
nclude/g++ --with-slibdir=/lib --with-system-zlib --enable-shared --libdir=/usr/lib --enable-checking i486-sus
e-linux
Thread model: posix
gcc version 3.1 20020415 (prerelease)
 /usr/lib/gcc-lib/i486-suse-linux/3.1/cc1plus -v -D__GNUC__=3 -D__GNUC_MINOR__=1 -D__GNUC_PATCHLEVEL__=0 -D__E
LF__ -Dunix -D__gnu_linux__ -Dlinux -D__ELF__ -D__unix__ -D__gnu_linux__ -D__linux__ -D__unix -D__linux -Asyst
em=posix -D__NO_INLINE__ -D__STDC_HOSTED__=1 -D_GNU_SOURCE -Acpu=i386 -Amachine=i386 -Di386 -D__i386 -D__i386_
_ -D__tune_i486__ c++_bug.cc -D__GNUG__=3 -D__DEPRECATED -D__EXCEPTIONS -D__GXX_ABI_VERSION=100 -quiet -dumpba
se c++_bug.cc -version -fmessage-length=0 -o /tmp/ccn7fscV.s
GNU CPP version 3.1 20020415 (prerelease) (cpplib) (i386 Linux/ELF)
GNU C++ version 3.1 20020415 (prerelease) (i486-suse-linux)
        compiled by GNU C version 3.1 20020415 (prerelease).
#include "..." search starts here:
#include <...> search starts here:
 /usr/include/g++
 /usr/include/g++/i486-suse-linux
 /usr/include/g++/backward
 /usr/local/include
 /usr/lib/gcc-lib/i486-suse-linux/3.1/include
 /usr/i486-suse-linux/include
 /usr/include
End of search list.
c++_bug.cc: In function `void bar()':
c++_bug.cc:15: choosing `double foo::operator[](double) const' over `int& foo::operator[](int)'
c++_bug.cc:15:   because worst conversion for the former is better than worst conversion for the latter
c++_bug.cc:15: choosing `double foo::operator[](double) const' over `int& foo::operator[](int)'
c++_bug.cc:15:   because worst conversion for the former is better than worst conversion for the latter
>How-To-Repeat:

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: text/plain; name="c++_bug.cc"
Content-Disposition: inline; filename="c++_bug.cc"

class foo
{
public:
	int &operator[] (int x);
	int operator[] (int x) const;
	double operator[] (double x) const;
};


void bar()
{
	foo arr;
	arr[2] = 5;             // OK
	int i = arr[10];        // OK
	double x = arr[0.5];    // ERROR
}

Re: c++/6375: GCC errouneously chooses operators

[nathan]

Synopsis: GCC errouneously chooses operators

State-Changed-From-To: open->closed
State-Changed-By: nathan
State-Changed-When: Sun Sep 15 05:14:45 2002
State-Changed-Why:
    not a bug.
    'double operator[](double) const' requires a qualification
    conversion on this.
    'int &operator[](int)' does not.
    hence they are ambiguous conversion sequence

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6375