// `+=` on a global variable loads the current value (not the initializer)
// before storing — same semantics as the explicit `g = g + 1` form.

#import "modules/std.sx";

g_counter : i64 = 0;

tick :: () {
    g_counter += 1;
    print("counter={}\n", g_counter);
}

main :: () -> void {
    // Test 1: += always produces 1 (BUG)
    out("--- Test 1: += (broken) ---\n");
    out("Expected: 1, 2, 3\n");
    i : i64 = 0;
    while i < 3 {
        tick();
        i += 1;
    }

    // Test 2: manual read-modify-write works correctly
    out("--- Test 2: = x + 1 (works) ---\n");
    out("Expected: 2, 3, 4\n");
    g_counter = g_counter + 1;
    print("counter={}\n", g_counter);
    g_counter = g_counter + 1;
    print("counter={}\n", g_counter);
    g_counter = g_counter + 1;
    print("counter={}\n", g_counter);
}