https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83024
--- Comment #2 from Guille <guille at berkeley dot edu> --- I should point out that the '-fconcepts' option isn't necessary, but '-std=c++1z' is (e.g. with '-std=c++11' it won't ICE but it also won't compile). So a minimal compilation command is: $ c++ t.c -std=c++1z
