[Bug libstdc++/92853] New: std::filesystem::path::operator+=(std::filesystem::path const&) corrupts the heap

[gcc at mattwhitlock dot name]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92853

            Bug ID: 92853
           Summary: std::filesystem::path::operator+=(std::filesystem::pat
                    h const&) corrupts the heap
           Product: gcc
           Version: 9.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gcc at mattwhitlock dot name
  Target Milestone: ---

// BEGIN test.cpp

#include <filesystem>

int main() {
        using std::filesystem::path;
        path p1{ "." }, p2{ "/" };
        p1 += p2;       // corrupts heap
        path p3{ p1 };  // CRASH!
        return 0;
}

// END test.cpp


$ g++ -std=gnu++2a -o test test.cpp

$ ./test
malloc(): corrupted top size
Aborted