[Bug c++/51818] New: [C++0x] Name mangling error using lambda expressions in GCC47

[Bug c++/51818] New: [C++0x] Name mangling error using lambda expressions in GCC47

[gccearlyadopter@trash-mail.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51818

             Bug #: 51818
           Summary: [C++0x] Name mangling error using lambda expressions
                    in GCC47
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: gccearlyadopter@trash-mail.com


The following program fails to compile:

#include <iostream>
#include <functional>
using std::cout;
using std::endl;

typedef std::function<void()> void_fun;

struct foo 
{
    void_fun bar = [=]() {
        cout << "foo::bar" << endl;
    };  
    void_fun baz = [=]() {
        cout << "foo::baz" << endl;
    };  
};

int main()
{
    foo f;
    f.bar();
    f.baz();
}


GCC 47 says: ... FATAL:Symbol
__ZSt4moveIRNUlvE_EEONSt16remove_referenceIT_E4typeEOS3_ already defined


Furthermore, it's not possible to call bar() from baz:

minimal_mangling_example.cpp: In lambda function:
minimal_mangling_example.cpp:12:5: error: invalid use of non-static data member
'foo::bar'
minimal_mangling_example.cpp:15:9: error: from this location

Unless the this pointer is passed and used explicitly:

    void_fun baz = [this]() {
        this->baz();
    }; 


That's wrong, too. The standard says in 5.1.2.7 ... "transforming id-
expressions referring to non-static class members into class member access
expressions using (*this) ...". Thus, baz should be able to call bar without
using this:


    void_fun baz = [=]() {
        bar();
    }; 



Best regards.

[Bug c++/51818] [C++0x] Name mangling error using lambda expressions in GCC47

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51818

--- Comment #1 from Jason Merrill <jason at gcc dot gnu.org> 2012-01-11 20:26:50 UTC ---
Author: jason
Date: Wed Jan 11 20:26:44 2012
New Revision: 183107

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=183107
Log:
    PR c++/51818
    * mangle.c (find_substitution): A type is only a substitution
    match if we're looking for a type.
    (write_nested_name): Use decl_mangling_context.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle3.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/mangle.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/51818] [C++0x] Name mangling error using lambda expressions in GCC47

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51818

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.0

--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> 2012-01-11 20:40:05 UTC ---
Fixed.