ref: b7f42e58b25d64fa8a03e8ac06a5f5e5e92c552a dir: /tests/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; }