message: Parse should fail if fmt string is not consumed.
diff: @@ -6177,6 +6177,8 @@ from_stream(std::basic_istream<CharT, Traits>& is, const CharT* fmt,
  else
  read(is, CharT{'%'}, width, modified);
  }
  + if (is.rdstate() != ios::goodbit && *fmt != CharT{} && !is.fail())
  + is.setstate(ios::failbit);
  if (!is.fail())
  {
  if (y != not_a_2digit_year)
  