From 4f5930cc5eb7899bb9a2766bb7b885c09d7d8155 Mon Sep 17 00:00:00 2001
From: Halid Odat <halidodat@gmail.com>
Date: Tue, 25 Aug 2020 10:15:44 +0200
Subject: [PATCH] Make `GcObject::contruct` not take 'this' (#660)

---
 boa/src/builtins/object/gcobject.rs | 12 +++++++-----
 boa/src/exec/new/mod.rs             | 13 ++-----------
 2 files changed, 9 insertions(+), 16 deletions(-)

diff --git a/boa/src/builtins/object/gcobject.rs b/boa/src/builtins/object/gcobject.rs
index 2dd0cbeb138..59dc448e657 100644
--- a/boa/src/builtins/object/gcobject.rs
+++ b/boa/src/builtins/object/gcobject.rs
@@ -2,7 +2,7 @@
 //!
 //! The `GcObject` is a garbage collected Object.
 
-use super::Object;
+use super::{Object, PROTOTYPE};
 use crate::{
     builtins::{
         function::{create_unmapped_arguments_object, BuiltInFunction, Function},
@@ -132,15 +132,17 @@ impl GcObject {
     }
 
     /// <https://tc39.es/ecma262/#sec-ecmascript-function-objects-construct-argumentslist-newtarget>
-    pub fn construct(&self, this: &Value, args: &[Value], ctx: &mut Interpreter) -> Result<Value> {
+    pub fn construct(&self, args: &[Value], ctx: &mut Interpreter) -> Result<Value> {
+        let this = Object::create(self.borrow().get(&PROTOTYPE.into())).into();
+
         let this_function_object = self.clone();
         let object = self.borrow();
         if let Some(function) = object.as_function() {
             if function.is_constructable() {
                 match function {
                     Function::BuiltIn(BuiltInFunction(function), _) => {
-                        function(this, args, ctx)?;
-                        Ok(this.clone())
+                        function(&this, args, ctx)?;
+                        Ok(this)
                     }
                     Function::Ordinary {
                         body,
@@ -152,7 +154,7 @@ impl GcObject {
                         // <https://tc39.es/ecma262/#sec-prepareforordinarycall>
                         let local_env = new_function_environment(
                             this_function_object,
-                            Some(this.clone()),
+                            Some(this),
                             Some(environment.clone()),
                             // Arrow functions do not have a this binding https://tc39.es/ecma262/#sec-function-environment-records
                             if flags.is_lexical_this_mode() {
diff --git a/boa/src/exec/new/mod.rs b/boa/src/exec/new/mod.rs
index 5bb6bec9e30..eb038481576 100644
--- a/boa/src/exec/new/mod.rs
+++ b/boa/src/exec/new/mod.rs
@@ -1,9 +1,5 @@
 use super::{Executable, Interpreter};
-use crate::{
-    builtins::{object::PROTOTYPE, Value},
-    syntax::ast::node::New,
-    BoaProfiler, Result,
-};
+use crate::{builtins::Value, syntax::ast::node::New, BoaProfiler, Result};
 
 impl Executable for New {
     fn run(&self, interpreter: &mut Interpreter) -> Result<Value> {
@@ -14,14 +10,9 @@ impl Executable for New {
         for arg in self.args() {
             v_args.push(arg.run(interpreter)?);
         }
-        let this = Value::new_object(None);
-        // Create a blank object, then set its __proto__ property to the [Constructor].prototype
-        this.as_object_mut()
-            .expect("this was not an object")
-            .set_prototype(func_object.get_field(PROTOTYPE));
 
         match func_object {
-            Value::Object(ref object) => object.construct(&this, &v_args, interpreter),
+            Value::Object(ref object) => object.construct(&v_args, interpreter),
             _ => Ok(Value::undefined()),
         }
     }