http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55671
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-12-13 11:25:37 UTC --- It gives it as an example then says "Warnings about conversions between signed and unsigned integers are disabled by default in C++ unless -Wsign-conversion is explicitly enabled." You only have to read the next paragraph.
