https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79727
Bug ID: 79727 Summary: -Wimplicit-fallthrough=3 doesn't seem to match any comments Product: gcc Version: 7.0.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: sgunderson at bigfoot dot com Target Milestone: --- Hi, I can't get the supposed fallthrough comments (on https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html) to work: gcc version 7.0.1 20170226 (experimental) [trunk revision 245744] (Debian 20170226-1) atum17:~> cat test.cc #include <stdio.h> #include <string> int main(int argc, char **argv) { switch (argc) { case 2: printf("something\n"); // -fallthrough case 3: printf("whatever\n"); break; } } atum17:~> /usr/lib/gcc-snapshot/bin/g++ -Wimplicit-fallthrough=3 -c test.cc test.cc: In function 'int main(int, char**)': test.cc:8:9: warning: this statement may fall through [-Wimplicit-fallthrough=] printf("something\n"); ~~~~~~^~~~~~~~~~~~~~~ test.cc:10:2: note: here case 3: ^~~~ I've tried a variety of the other patterns that are supposed to match, but I can't get it to work on level 3. Level 2 appears to work as documented.