http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58781
--- Comment #3 from Ed Smith-Rowland <3dw4rd at verizon dot net> --- Q; Is this a regression? A: No. See http://ideone.com/8JS3Yf This is gcc-4.8.1 (needed a space between "" and _s but still errors with this: ----------------------------------------------------------- prog.cpp: In function ‘int f()’: prog.cpp:7:22: error: converting to execution character set: Invalid or incomplete multibyte or wide character using b=decltype(U"\x8111"_s); ^ prog.cpp:8:22: error: converting to execution character set: Invalid or incomplete multibyte or wide character using c=decltype(U" \x1181"_s); ^ -----------------------------------------------------------