https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79961
--- Comment #2 from Pedro Alves <palves at redhat dot com> --- Yeah, I think it's too late, and it'd cause trouble with compatibility with clang. Note that the documentation for the attribute(format) <https://gcc.gnu.org/onlinedocs/gcc-6.3.0/gcc/Common-Function-Attributes.html> says: "Since non-static C++ methods have an implicit this argument, the arguments of such methods should be counted from two, not one, when giving values for string-index and first-to-check." but the documentation for the nonnull attribute doesn't say anything about it. Maybe that bit could be factored out somehow, or copied, or xrefed.
