[Bug objc++/57607] New: g++ cannot distinguish obj-c message call from c++11 lambda

["antonbachin at yahoo dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57607

            Bug ID: 57607
           Summary: g++ cannot distinguish obj-c message call from c++11
                    lambda
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: objc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: antonbachin at yahoo dot com

The following program (test.mm) has both a lambda and a message call:

    #import <cstdlib>
    #import <iostream>

    #import <Foundation/NSString.h>

    int main()
    {
        [] () { std::cout << "Hello world!" << std::endl; }();

        std::cout << [@"Hello world!" UTF8String] << std::endl;

        return EXIT_SUCCESS;
    }

Compiling with gcc 4.8.1 results in:

    > g++-mp-4.8 -std=c++11 test.mm && ./a.out
    test.mm: In function 'int main()':
    test.mm:8:6: error: expected identifier before ']' token
         [] () { std::cout << "Hello world!" << std::endl; }();
          ^
    test.mm:8:6: error: '<expression error>' is not an Objective-C class name
or
        alias
    test.mm:8:6: error: objective-c++ message argument(s) are expected before
        ']' token
    test.mm:8:11: error: expected ';' before '{' token
         [] () { std::cout << "Hello world!" << std::endl; }();
               ^
    test.mm:8:57: error: expected primary-expression before ')' token
         [] () { std::cout << "Hello world!" << std::endl; }();
                                                             ^

(I know that this wouldn't link, but I'm not getting that far). Meanwhile, with
clang:

    > clang++ -std=c++11 -framework Foundation test.mm && ./a.out
    Hello world!
    Hello world!

Version information:

    > g++-mp-4.8 --version
    g++-mp-4.8 (MacPorts gcc48 4.8.1_0) 4.8.1
    Copyright (C) 2013 Free Software Foundation, Inc.
    This is free software; see the source for copying conditions.  There is NO
    warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

    > clang++ --version
    Apple clang version 4.0 (tags/Apple/clang-421.0.60) (based on LLVM 3.1svn)
    Target: x86_64-apple-darwin12.4.0
    Thread model: posix

Compiling with -Wall -Wextra makes no difference in the output for either
compiler.