TypeError when to_object is passed null or undefined (#518)

Co-authored-by: HalidOdat <halidodat@gmail.com>

boa/src/exec/mod.rs

@@ -425,7 +425,9 @@ impl Interpreter {
     #[allow(clippy::wrong_self_convention)]
     pub(crate) fn to_object(&mut self, value: &Value) -> ResultValue {
         match value {
-            Value::Undefined | Value::Null => Err(Value::undefined()),
+            Value::Undefined | Value::Null => {
+                self.throw_type_error("cannot convert 'null' or 'undefined' to object")
+            }
             Value::Boolean(boolean) => {
                 let proto = self
                     .realm

boa/src/exec/tests.rs

@@ -927,3 +927,15 @@ fn calling_function_with_unspecified_arguments() {
 
     assert_eq!(forward(&mut engine, scenario), "undefined");
 }
+
+#[test]
+fn to_object() {
+    let realm = Realm::create();
+    let mut engine = Interpreter::new(realm);
+
+    assert!(engine
+        .to_object(&Value::undefined())
+        .unwrap_err()
+        .is_object());
+    assert!(engine.to_object(&Value::null()).unwrap_err().is_object());
+}