[Bug libstdc++/87846] New: std::filesystem::create_directories with a path with a trailing slash does not create any directory

[arnaud02 at users dot sourceforge.net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87846

            Bug ID: 87846
           Summary: std::filesystem::create_directories with a path with a
                    trailing slash does not create any directory
           Product: gcc
           Version: 8.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: arnaud02 at users dot sourceforge.net
  Target Milestone: ---

Calling std::filesystem::create_directories with a path with a trailing
separator (e.g. "./a/b/") does not create any directory.
VS 2017 15.8 creates the desired directories.

Is GCC incorrect?

>cat fs.cpp 
//
https://developercommunity.visualstudio.com/content/problem/278829/stdfilesystemcreate-directories-returns-false-if-p.html
#include <filesystem>
#include <iostream>

namespace fs = std::filesystem;

int main()
{
  fs::path d{"./a/b/"};
  // bug: d is not created due to trailing slash when built with GCC 8. Works
with VS2017.8.
  fs::create_directories(d);

  std::cout << std::boolalpha
            << fs::exists(d) << ' '
            << fs::is_directory(d) << '\n';
  for (auto const& e : fs::recursive_directory_iterator("."))
    std::cout << "In current_path: " << e.path() << '\n';
}
>g++ -std=c++17 fs.cpp -lstdc++fs 
>./a.out 
false false
In current_path: "./a.out"
In current_path: "./fs.cpp"
>gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/buildarea/opt/gcc/gcc-820-rh6/libexec/gcc/x86_64-pc-linux-gnu/8.2.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /tmp/gcc8/gcc-build/srcdir/gcc-8.2.0/configure
--prefix=/buildarea/opt/gcc/gcc-820-rh6 --enable-languages=c,c++,fortran
--disable-multilib
Thread model: posix