[Bug libstdc++/60711] basic_ostringstream,basic_ostream,u16string,char16_t do not work together

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60711

--- Comment #12 from Marc Glisse <glisse at gcc dot gnu.org> ---
Before saying that there is a problem with libstdc++, did you try other
implementations? clang++ with libc++ gives the same error. That's just not how
streams are supposed to be used (pretend it is a pure virtual base class if
that helps), please invest in a book.