[Bug libstdc++/105857] codecvt::do_length causes unexpected buffer overflow

[andysem at mail dot ru via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105857

--- Comment #1 from andysem at mail dot ru ---
Created attachment 53089
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53089&action=edit
Test case to reproduce the problem.