http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50758
--- Comment #4 from Dominique d'Humieres <dominiq at lps dot ens.fr> 2011-10-17 15:42:09 UTC --- > Are you still seing this with commit r180090? I have bootstrapped revision 180087 with the following patch --- /opt/gcc/_clean/libcpp/line-map.c 2011-10-17 12:04:41.000000000 +0200 +++ /opt/gcc/work/libcpp/line-map.c 2011-10-17 15:36:30.000000000 +0200 @@ -625,7 +625,7 @@ source_location linemap_macro_map_loc_to_exp_point (const struct line_map *map, source_location location) { - unsigned token_no; + unsigned token_no __attribute__ ((__unused__)); linemap_assert (linemap_macro_expansion_map_p (map) && location >= MAP_START_LOCATION (map)); I guess that revision 180090 is a similar fix that should work (I'll have the answer in a couple hours;-). Last question: is the warning bogus or not? If no, why? If yes, I'll open a new PR.