[Bug libstdc++/120029] Dangling iterator usage in std::filesystem::path::operator+=(const std::filesystem::path &p) when this == p

[yhx12243 at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120029

--- Comment #4 from Haoxiang Yu <yhx12243 at gmail dot com> ---
(In reply to Jonathan Wakely from comment #3)
> The simplest fix is just:
> 
> --- a/libstdc++-v3/src/c++17/fs_path.cc
> +++ b/libstdc++-v3/src/c++17/fs_path.cc
> @@ -880,6 +880,9 @@ path::operator+=(const path& p)
>        return *this;
>      }
>  
> +  if (&p == this) [[unlikely]]
> +    return *this += p.native();
> +
>  #if _GLIBCXX_FILESYSTEM_IS_WINDOWS
>    if (_M_type() == _Type::_Root_name
>        || (_M_type() == _Type::_Filename && _M_pathname.size() == 1))

Yes it is indeed the simplest way to resolve. The main question is that is it
worthy to handle these case in a non-copy way.