[Bug c++/115779] New: boost-flat_map begin/end is the same for non empty container

[joerg.richter@pdv-fs.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115779

            Bug ID: 115779
           Summary: boost-flat_map begin/end is the same for non empty
                    container
           Product: gcc
           Version: 14.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: joerg.richter@pdv-fs.de
  Target Milestone: ---

Please see:

https://godbolt.org/z/T5nb4x6sv

I've noticed this while upgrading from boost 1.83 zu 1.85.
The map is not empty but begin() == end(). This does not happen without
optimization or when using clang.  I haven't got time to reduce this.

I think this is a compiler bug, because in my original code this was magically
fixed when commenting some dead code.