Fix ModuloBox E0046 error and add null literal support

Co-authored-by: moe-charm <217100418+moe-charm@users.noreply.github.com>

test_array_length_fix.nyash

@@ -0,0 +1,43 @@
+// Test for ArrayBox.length() functionality 
+static box ArrayLengthTest {
+    init { console }
+    
+    main() {
+        me.console = new ConsoleBox()
+        me.console.log("🧪 Testing ArrayBox.length() functionality")
+        
+        // Test 1: Empty array
+        local empty_array = new ArrayBox()
+        local empty_length = empty_array.length()
+        me.console.log("Empty array length: " + empty_length)  // Expected: 0
+        
+        // Test 2: Array with elements
+        local test_array = new ArrayBox()
+        test_array.push("first")
+        test_array.push("second") 
+        test_array.push("third")
+        
+        local length_after_push = test_array.length()
+        me.console.log("Array length after 3 pushes: " + length_after_push)  // Expected: 3
+        
+        // Test 3: Array after pop
+        local popped = test_array.pop()
+        me.console.log("Popped element: " + popped)
+        
+        local length_after_pop = test_array.length()
+        me.console.log("Array length after pop: " + length_after_pop)  // Expected: 2
+        
+        // Test 4: Verify elements are still accessible
+        local first_element = test_array.get(0)
+        local second_element = test_array.get(1) 
+        me.console.log("Element at index 0: " + first_element)
+        me.console.log("Element at index 1: " + second_element)
+        
+        // Test 5: Edge case - accessing beyond length
+        local beyond_length = test_array.get(5)
+        me.console.log("Element beyond length: " + beyond_length)  // Expected: null
+        
+        me.console.log("✅ ArrayBox.length() tests completed")
+        return "ArrayBox functionality verified"
+    }
+}