You must be a C++ user -- I (a C guy) immediately thought "what? No, that's in -Wextra, not -Wall", checked the man page to confirm, and sure enough, it differs

You must be a C++ user -- I (a C guy) immediately thought "what? No, that's in -Wextra, not -Wall", checked the man page to confirm, and sure enough, it differs (-Wall includes sign-compare when compiling C++, but not C).