http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59087
--- Comment #7 from Ed Smith-Rowland <3dw4rd at verizon dot net> --- OK, it took me a while to remember this (even though I put it in myself). By default, g++ -std=c++11/1y intercepts numeric suffixes for C++11 user-defined literals. By default g++ -std=gnu++11/1y allow complex and fixed-point literals suffixes to be interpreted by the implementation - Allowing iF suffix for example to be _Complex. This is why http://melpon.org/wandbox/permlink/CnsddYRxUohlCGF1 "worked" and my tree (where I used -std=c++1*) "didn't work". See http://gcc.gnu.org/gcc-4.8/changes.html. Using g++ -std=c++11 -fext-numeric-literals allows your code. Using g++ -std=gnu++11 -fno-numeric-literals allows iF to be searched for user-defined literal (there isn't one so error). g++ is working as intended.
