[Bug c++/107488] New: [13 Regression] -Werror=dangling-reference false positives in cppunit

["slyfox at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107488

            Bug ID: 107488
           Summary: [13 Regression] -Werror=dangling-reference false
                    positives in cppunit
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: slyfox at gcc dot gnu.org
  Target Milestone: ---

cppunit-1.15.1 and a few other projects fail to compile due to -Werror on
-Werror=dangling-reference. I think those are false positives. Extracted
example from cppunit:

// $ cat a.cpp.cpp

#include <vector>

int attributesAsString(std::vector<int> & v)
{
  int attributes;

  std::vector<int>::const_iterator itAttribute = v.begin();
  while ( itAttribute != v.end() )
  {
    const int &attribute = *itAttribute++;
    attributes += attribute;
  }

  return attributes;
}

$ g++-13.0.0 -Werror=dangling-reference -c a.cpp.cpp -o a.o
a.cpp.cpp: In function 'int attributesAsString(std::vector<int>&)':
a.cpp.cpp:12:16: error: possibly dangling reference to a temporary
[-Werror=dangling-reference]
   12 |     const int &attribute = *itAttribute++;
      |                ^~~~~~~~~
a.cpp.cpp:12:40: note: the temporary was destroyed at the end of the full
expression 'itAttribute.__gnu_cxx::__normal_iterator<const int*,
std::vector<int> >::operator++(0).__gnu_cxx::__normal_iterator<const int*,
std::vector<int> >::operator*()'
   12 |     const int &attribute = *itAttribute++;
      |                                        ^~

$ g++-13.0.0 -v
Using built-in specs.
COLLECT_GCC=/<<NIX>>/gcc-13.0.0/bin/g++
COLLECT_LTO_WRAPPER=/<<NIX>>/gcc-13.0.0/libexec/gcc/x86_64-unknown-linux-gnu/13.0.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with:
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 13.0.0 20221030 (experimental) (GCC)