[Bug c++/53333] New: Initializer lists in std=c++03 mode must be an error

[Bug c++/53333] New: Initializer lists in std=c++03 mode must be an error

[fpelliccioni at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53333

             Bug #: 53333
           Summary: Initializer lists in std=c++03 mode must be an error
    Classification: Unclassified
           Product: gcc
           Version: 4.7.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: fpelliccioni@gmail.com


Hi,

The following code, compiled with -std=c++03 option, emits a warning instead of
an error.

Regards,
Fernando.


//Begin code
#include <string>
#include <utility>

void foo( std::string ) {}
void foo( std::pair<std::string, std::string> ) {}

int main( /* int argc, char* argv[] */ )
{
    foo( {"k0", "v0"} );

  return 0;
}

// End code



#g++ -std=c++03 gcc_warning.cpp
gcc_warning.cpp: In function 'int main()':
gcc_warning.cpp:9:5: warning: extended initializer lists only available with
-std=c++11 or -std=gnu++11 [enabled by default]
gcc_warning.cpp:9:20: error: call of overloaded 'foo(<brace-enclosed
initializer list>)' is ambiguous
gcc_warning.cpp:9:20: note: candidates are:
gcc_warning.cpp:4:6: note: void foo(std::string)
gcc_warning.cpp:5:6: note: void foo(std::pair<std::basic_string<char>,
std::basic_string<char> >)

[Bug c++/53333] Initializer lists in std=c++03 mode must be an error

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53333

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu.org

--- Comment #1 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-05-12 16:57:26 UTC ---
Seems on purpose to me. Of course changing the warning to an error would be
trivial. Maybe Jason can comment on why we have a warning here.

[Bug c++/53333] Initializer lists in std=c++03 mode must be an error

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53333

--- Comment #2 from Marc Glisse <glisse at gcc dot gnu.org> 2012-05-12 19:46:08 UTC ---
There is -pedantic-errors if you want an error.

[Bug c++/53333] Initializer lists in std=c++03 mode must be an error

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53333

Jason Merrill <jason at gcc dot gnu.org> changed:

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

--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> 2012-05-12 20:46:09 UTC ---
(In reply to comment #2)
> There is -pedantic-errors if you want an error.

Precisely.

[Bug c++/53333] Initializer lists in std=c++03 mode must be an error

[fpelliccioni at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53333

--- Comment #4 from Fernando Pelliccioni <fpelliccioni at gmail dot com> 2012-05-12 20:59:58 UTC ---
For other features of C++11 don't need -pedantic-errors to emit an error.
See..


#include <string>

void foo( std::string && str ) {}

int main( /* int argc, char* argv[] */ )
{
    foo( "k0" );

  return 0;
}


#g++ -std=c++03 gcc_warning.cpp
gcc_warning.cpp:3:23: error: expected ',' or '...' before '&&' token


It doesn't seem consistent.
What is the criteria?

[Bug c++/53333] Initializer lists in std=c++03 mode must be an error

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53333

--- Comment #5 from Marc Glisse <glisse at gcc dot gnu.org> 2012-05-12 21:57:05 UTC ---
(In reply to comment #4)
> For other features of C++11 don't need -pedantic-errors to emit an error.
[...]
> It doesn't seem consistent.
> What is the criteria?

Allowing {} is a rather isolated extension that doesn't interfere much with
anything. Rvalue reference is perhaps the worst example you could pick as it
changes the behavior all over the place and can easily break code. I don't know
if there are official criteria, the choices may be questionable, but I don't
see that it matters that much...

[Bug c++/53333] Initializer lists in std=c++03 mode must be an error

[fpelliccioni at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53333

--- Comment #6 from Fernando Pelliccioni <fpelliccioni at gmail dot com> 2012-05-12 23:53:30 UTC ---
(In reply to comment #5)
> (In reply to comment #4)
> > For other features of C++11 don't need -pedantic-errors to emit an error.
> [...]
> > It doesn't seem consistent.
> > What is the criteria?
> 
> Allowing {} is a rather isolated extension that doesn't interfere much with
> anything. Rvalue reference is perhaps the worst example you could pick as it
> changes the behavior all over the place and can easily break code. I don't know
> if there are official criteria, the choices may be questionable, but I don't
> see that it matters that much...

I got it. Thanks!