gistfile1.txt

awf-macbookair1:t awf$ cat foo.c
#include <stdio.h>

int main() {

   if(1)
     goto foo;
     goto foo;

   printf("here\n");

   foo:
     return 1;
}

awf-macbookair1:t awf$ clang -Wall -Werror foo.c
awf-macbookair1:t awf$ ls a.out
a.out
awf-macbookair1:t awf$ rm a.out
awf-macbookair1:t awf$ clang -Weverything -Werror foo.c
foo.c:9:4: error: will never be executed [-Werror,-Wunreachable-code]
   printf("here\n");
   ^~~~~~
foo.c:7:6: error: will never be executed [-Werror,-Wunreachable-code]
     goto foo;
     ^~~~~~~~
2 errors generated.
awf-macbookair1:t awf$ ls a.out
ls: a.out: No such file or directory