foo.c: In function 'main':
foo.c:11:34: warning: unused variable 'd' [-Wunused-variable]
   11 |         int a = 0, b = 0, c = 0, d = 0;
      |                                  ^
foo.c:11:27: warning: unused variable 'c' [-Wunused-variable]
   11 |         int a = 0, b = 0, c = 0, d = 0;
      |                           ^
foo.c:11:20: warning: unused variable 'b' [-Wunused-variable]
   11 |         int a = 0, b = 0, c = 0, d = 0;
      |                    ^
foo.c:11:13: warning: unused variable 'a' [-Wunused-variable]
   11 |         int a = 0, b = 0, c = 0, d = 0;
      |             ^

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