https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127748
--- Comment #3 from Gabriel Ravier <gabravier at gmail dot com> --- AIUI a singleton-capture warning would be linear, much like e.g. Prolog's simpleton variable warning (which is basically the concept I was thinking of) - is genmatch architectured particularly oddly such that such a check would be particularly complex?
