ref: 81b6d6367c1c9c957ca910e5f8b5fb70adfa9c21 dir: /tests/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; }