ref: 2a61dfcd596b6da4d31379663a20e4fe0566cc17 dir: /tests/cc/execute/0043-union.c/
int main() { union { int a; int b; } u; u.a = 1; u.b = 3; if (u.a != 3 || u.b != 3) return 1; return 0; }