Re: Second GCC 4.7.0 Release Candidate available from gcc.gnu.org

[Jonathan Wakely <jwakely dot gcc at gmail dot com>]

2012/3/19 PaweÅ Sikora:
> On Wednesday 14 of March 2012 12:22:41 Richard Guenther wrote:
>>
>> GCC 4.7.0 Release Candidate available from gcc.gnu.org
>>
>> A second release candidate for GCC 4.7.0 is available from
>>
>> Âftp://gcc.gnu.org/pub/gcc/snapshots/4.7.0-RC-20120314
>>
>> and shortly its mirrors. ÂIt has been generated from SVN revision 185376.
>>
>> I have so far bootstrapped and tested the release candidate on
>> x86_64-linux. ÂPlease test it and report any issues to bugzilla.
>
> i'd like to ask about simple code snipet rejected by 4.7.0-RC2:
>
> #include <boost/shared_ptr.hpp>
> #include <map>
> #include <string>
>
> typedef boost::shared_ptr<std::string> HString;
> typedef std::map<std::string,HString> StrAttribsT;
> StrAttribsT m_str_attribs;
>
> void foo(const char* attribName, const char* value)
> {
> Â Â Â Âm_str_attribs.insert(std::make_pair(attribName, new std::string(value)));
> }
>
> it compiles cleanly with 'g++46 -std=gnu++0x' but 4.7 rejects this code.
> is it an effect of 'name lookup changes'? (http://gcc.gnu.org/gcc-4.7/porting_to.html)

No, the change is in how std::pair is constructed, the code can be reduced to:

#include <boost/shared_ptr.hpp>
#include <string>

typedef boost::shared_ptr<std::string> HString;

void foo(const char* attribName)
{
    const std::pair<const std::string, HString> a
        = std::make_pair(attribName, new std::string);
}

Probably caused by http://gcc.gnu.org/viewcvs?view=revision&revision=174464

I haven't looked in enough detail to see if the change in behaviour is
correct or a regression.