https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105222
--- Comment #3 from 康桓瑋 <hewillk at gmail dot com> --- (In reply to 康桓瑋 from comment #2) > And gcc accepts the following invalid syntax: > > int main() { > auto b = requires { true ? [] : [] {}; }; > } > > https://godbolt.org/z/xeE1oYs1Y It seems like the single [] makes gcc totally broken. int main() { auto b = requires { true ? [] : []!-!-[]?[]; }; } https://godbolt.org/z/EPTE6zf5E