Implement erased objects

boa_cli/src/debug/function.rs

@@ -1,4 +1,5 @@
 use boa_engine::{
+    builtins::function::OrdinaryFunction,
     js_string,
     object::ObjectInitializer,
     vm::flowgraph::{Direction, Graph},
@@ -80,9 +81,7 @@ fn flowgraph(_this: &JsValue, args: &[JsValue], context: &mut Context) -> JsResu
         }
     }
 
-    let object = object.borrow();
-
-    let Some(function) = object.as_function() else {
+    let Some(function) = object.downcast_ref::<OrdinaryFunction>() else {
         return Err(JsNativeError::typ()
             .with_message("expected an ordinary function object")
             .into());
@@ -112,8 +111,7 @@ fn bytecode(_: &JsValue, args: &[JsValue], _: &mut Context) -> JsResult<JsValue>
             .with_message(format!("expected object, got {}", value.type_of()))
             .into());
     };
-    let object = object.borrow();
-    let Some(function) = object.as_function() else {
+    let Some(function) = object.downcast_ref::<OrdinaryFunction>() else {
         return Err(JsNativeError::typ()
             .with_message("expected an ordinary function object")
             .into());
@@ -124,8 +122,7 @@ fn bytecode(_: &JsValue, args: &[JsValue], _: &mut Context) -> JsResult<JsValue>
 }
 
 fn set_trace_flag_in_function_object(object: &JsObject, value: bool) -> JsResult<()> {
-    let object = object.borrow();
-    let Some(function) = object.as_function() else {
+    let Some(function) = object.downcast_ref::<OrdinaryFunction>() else {
         return Err(JsNativeError::typ()
             .with_message("expected an ordinary function object")
             .into());

boa_cli/src/debug/object.rs

@@ -18,7 +18,7 @@ fn id(_: &JsValue, args: &[JsValue], _: &mut Context) -> JsResult<JsValue> {
     };
 
     let ptr: *const _ = object.as_ref();
-    Ok(js_string!(format!("0x{:X}", ptr as usize)).into())
+    Ok(js_string!(format!("0x{:X}", ptr.cast::<()>() as usize)).into())
 }
 
 pub(super) fn create_object(context: &mut Context) -> JsObject {

boa_engine/src/bigint.rs

@@ -1,6 +1,7 @@
 //! Boa's implementation of ECMAScript's bigint primitive type.
 
-use crate::{builtins::Number, error::JsNativeError, JsResult};
+use crate::{builtins::Number, error::JsNativeError, JsData, JsResult};
+use boa_gc::{Finalize, Trace};
 use num_integer::Integer;
 use num_traits::{pow::Pow, FromPrimitive, One, ToPrimitive, Zero};
 use std::{
@@ -17,7 +18,9 @@ use serde::{Deserialize, Serialize};
 
 /// JavaScript bigint primitive rust type.
 #[cfg_attr(feature = "deser", derive(Serialize, Deserialize))]
-#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Trace, Finalize, JsData)]
+// Safety: `JsBigInt` doesn't contain any traceable types.
+#[boa_gc(unsafe_empty_trace)]
 pub struct JsBigInt {
     inner: Rc<RawBigInt>,
 }

boa_engine/src/builtins/array/array_iterator.rs

@@ -7,16 +7,17 @@
 
 use crate::{
     builtins::{
-        iterable::create_iter_result_object, Array, BuiltInBuilder, IntrinsicObject, JsValue,
+        iterable::create_iter_result_object, typed_array::TypedArray, Array, BuiltInBuilder,
+        IntrinsicObject, JsValue,
     },
     context::intrinsics::Intrinsics,
     error::JsNativeError,
     js_string,
-    object::{JsObject, ObjectData},
+    object::JsObject,
     property::{Attribute, PropertyNameKind},
     realm::Realm,
     symbol::JsSymbol,
-    Context, JsResult,
+    Context, JsData, JsResult,
 };
 use boa_gc::{Finalize, Trace};
 use boa_profiler::Profiler;
@@ -27,8 +28,8 @@ use boa_profiler::Profiler;
 ///  - [ECMAScript reference][spec]
 ///
 /// [spec]: https://tc39.es/ecma262/#sec-array-iterator-objects
-#[derive(Debug, Clone, Finalize, Trace)]
-pub struct ArrayIterator {
+#[derive(Debug, Clone, Finalize, Trace, JsData)]
+pub(crate) struct ArrayIterator {
     array: JsObject,
     next_index: u64,
     #[unsafe_ignore_trace]
@@ -88,7 +89,7 @@ impl ArrayIterator {
         let array_iterator = JsObject::from_proto_and_data_with_shared_shape(
             context.root_shape(),
             context.intrinsics().objects().iterator_prototypes().array(),
-            ObjectData::array_iterator(Self::new(array, kind)),
+            Self::new(array, kind),
         );
         array_iterator.into()
     }
@@ -102,10 +103,9 @@ impl ArrayIterator {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-%arrayiteratorprototype%.next
     pub(crate) fn next(this: &JsValue, _: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        let mut array_iterator = this.as_object().map(JsObject::borrow_mut);
-        let array_iterator = array_iterator
-            .as_mut()
-            .and_then(|obj| obj.as_array_iterator_mut())
+        let mut array_iterator = this
+            .as_object()
+            .and_then(JsObject::downcast_mut::<Self>)
             .ok_or_else(|| JsNativeError::typ().with_message("`this` is not an ArrayIterator"))?;
         let index = array_iterator.next_index;
         if array_iterator.done {
@@ -116,7 +116,7 @@ impl ArrayIterator {
             ));
         }
 
-        let len = if let Some(f) = array_iterator.array.borrow().as_typed_array() {
+        let len = if let Some(f) = array_iterator.array.downcast_ref::<TypedArray>() {
             if f.is_detached() {
                 return Err(JsNativeError::typ()
                     .with_message(