Disallow changing type of already created objects (boa-dev#3410)

* Disallow changing type of already created objects

* Fix regressions

* Fix spec steps

* Rollback restrictions and add new conversion

boa_ast/src/expression/regexp.rs

@@ -35,21 +35,21 @@ pub struct RegExpLiteral {
 }
 
 impl RegExpLiteral {
-    /// Create a new [`RegExp`].
+    /// Create a new [`RegExpLiteral`].
     #[inline]
     #[must_use]
     pub const fn new(pattern: Sym, flags: Sym) -> Self {
         Self { pattern, flags }
     }
 
-    /// Get the pattern part of the [`RegExp`].
+    /// Get the pattern part of the [`RegExpLiteral`].
     #[inline]
     #[must_use]
     pub const fn pattern(&self) -> Sym {
         self.pattern
     }
 
-    /// Get the flags part of the [`RegExp`].
+    /// Get the flags part of the [`RegExpLiteral`].
     #[inline]
     #[must_use]
     pub const fn flags(&self) -> Sym {

boa_cli/src/main.rs

@@ -325,7 +325,7 @@ fn evaluate_files(
                 Err(v) => eprintln!("Uncaught {v}"),
             }
         } else if args.module {
-            let result = (|| {
+            let result: JsResult<PromiseState> = (|| {
                 let module = Module::parse(Source::from_bytes(&buffer), None, context)?;
 
                 loader.insert(
@@ -334,10 +334,10 @@ fn evaluate_files(
                     module.clone(),
                 );
 
-                let promise = module.load_link_evaluate(context)?;
+                let promise = module.load_link_evaluate(context);
 
                 context.run_jobs();
-                promise.state()
+                Ok(promise.state())
             })();
 
             match result {

boa_engine/src/builtins/error/type.rs

@@ -20,7 +20,8 @@ use crate::{
     context::intrinsics::{Intrinsics, StandardConstructor, StandardConstructors},
     error::JsNativeError,
     js_string,
-    object::{internal_methods::get_prototype_from_constructor, JsObject, ObjectData, ObjectKind},
+    native_function::NativeFunctionObject,
+    object::{internal_methods::get_prototype_from_constructor, JsObject, ObjectData},
     property::Attribute,
     realm::Realm,
     string::{common::StaticJsStrings, utf16},
@@ -115,15 +116,6 @@ pub(crate) struct ThrowTypeError;
 
 impl IntrinsicObject for ThrowTypeError {
     fn init(realm: &Realm) {
-        fn throw_type_error(_: &JsValue, _: &[JsValue], _: &mut Context<'_>) -> JsResult<JsValue> {
-            Err(JsNativeError::typ()
-                .with_message(
-                    "'caller', 'callee', and 'arguments' properties may not be accessed on strict mode \
-                    functions or the arguments objects for calls to them",
-                )
-                .into())
-        }
-
         let obj = BuiltInBuilder::with_intrinsic::<Self>(realm)
             .prototype(realm.intrinsics().constructors().function().prototype())
             .static_property(utf16!("length"), 0, Attribute::empty())
@@ -132,12 +124,21 @@ impl IntrinsicObject for ThrowTypeError {
 
         let mut obj = obj.borrow_mut();
 
-        obj.extensible = false;
-        *obj.kind_mut() = ObjectKind::NativeFunction {
-            function: NativeFunction::from_fn_ptr(throw_type_error),
+        *obj.as_native_function_mut()
+            .expect("`%ThrowTypeError%` must be a function") = NativeFunctionObject {
+            f: NativeFunction::from_fn_ptr(|_, _, _| {
+                Err(JsNativeError::typ()
+                    .with_message(
+                        "'caller', 'callee', and 'arguments' properties may not be accessed on strict mode \
+                        functions or the arguments objects for calls to them",
+                    )
+                    .into())
+            }),
             constructor: None,
-            realm: realm.clone(),
-        }
+            realm: Some(realm.clone()),
+        };
+
+        obj.extensible = false;
     }
 
     fn get(intrinsics: &Intrinsics) -> JsObject {