gcc/testsuite/gcc.dg/c11-parm-omit-3.c

/* Test omitted parameter names not in C11: -pedantic -Wno-c11-c2x-compat.  */
/* { dg-do compile } */
/* { dg-options "-std=c11 -pedantic -Wno-c11-c2x-compat" } */

void f (int) { }