.sh

$ clang -Wall test.c
test.c:14:3: warning: null passed to a callee that requires a non-null argument [-Wnonnull]
  safelyPrintImportant(NULL);
  ^                    ~~~~
test.c:8:39: note: callee declares array parameter as static here
void safelyPrintImportant(important_t imp[static 1]) {
                                      ^  ~~~~~~~~~~
                                      
                                      
$ clang --version
Apple LLVM version 9.0.0 (clang-900.0.38)
Target: x86_64-apple-darwin17.2.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin