[Bug libstdc++/86910] std::filesystem::create_directories doesn't set error code or throw while violating postcondition.

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86910

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |redi at gcc dot gnu.org
   Target Milestone|---                         |8.3

--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The proposed new direction is:

In case mkdir() fails because p already exists, if p resolves to an existing
directory, no error is reported, otherwise an error is reported.

And consistently for create_directory and create_directories, of course.