Fixed function object constructable/callable (#409)

- Maded arrow functions non-constructable
 - Simplified Function object and removed FunctionKind
 - Rnamed create_ordinary -> ordinary, create_builtin -> builtin
 - Added name and length properties in global objects

boa/src/builtins/array/mod.rs

@@ -1031,7 +1031,7 @@ impl Array {
         make_builtin_fn(Self::slice, "slice", &prototype, 2);
         make_builtin_fn(Self::some, "some", &prototype, 2);
 
-        let array = make_constructor_fn(Self::make_array, global, prototype);
+        let array = make_constructor_fn("Array", 1, Self::make_array, global, prototype, true);
 
         // Static Methods
         make_builtin_fn(Self::is_array, "isArray", &array, 1);

boa/src/builtins/bigint/mod.rs

@@ -96,14 +96,14 @@ impl BigInt {
         ))
     }
 
-    // /// `BigInt.prototype.valueOf()`
-    // ///
-    // /// The `valueOf()` method returns the wrapped primitive value of a Number object.
-    // ///
-    // /// More information:
-    // ///  - [ECMAScript reference][spec]
-    // ///  - [MDN documentation][mdn]
-    // ///
+    /// `BigInt.prototype.valueOf()`
+    ///
+    /// The `valueOf()` method returns the wrapped primitive value of a Number object.
+    ///
+    /// More information:
+    ///  - [ECMAScript reference][spec]
+    ///  - [MDN documentation][mdn]
+    ///
     /// [spec]: https://tc39.es/ecma262/#sec-bigint.prototype.valueof
     /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt/valueOf
     pub(crate) fn value_of(
@@ -124,7 +124,7 @@ impl BigInt {
         make_builtin_fn(Self::to_string, "toString", &prototype, 1);
         make_builtin_fn(Self::value_of, "valueOf", &prototype, 0);
 
-        make_constructor_fn(Self::make_bigint, global, prototype)
+        make_constructor_fn("BigInt", 1, Self::make_bigint, global, prototype, false)
     }
 
     /// Initialise the `BigInt` object on the global object.

boa/src/builtins/boolean/mod.rs

@@ -115,7 +115,14 @@ impl Boolean {
         make_builtin_fn(Self::to_string, "toString", &prototype, 0);
         make_builtin_fn(Self::value_of, "valueOf", &prototype, 0);
 
-        make_constructor_fn(Self::construct_boolean, global, prototype)
+        make_constructor_fn(
+            "Boolean",
+            1,
+            Self::construct_boolean,
+            global,
+            prototype,
+            true,
+        )
     }
 
     /// Initialise the `Boolean` object on the global object.

boa/src/builtins/error/mod.rs

@@ -72,9 +72,10 @@ impl Error {
     pub(crate) fn create(global: &Value) -> Value {
         let prototype = Value::new_object(Some(global));
         prototype.set_field("message", Value::from(""));
-        prototype.set_field("name", Value::from("Error"));
+
         make_builtin_fn(Self::to_string, "toString", &prototype, 0);
-        make_constructor_fn(Self::make_error, global, prototype)
+
+        make_constructor_fn("Error", 1, Self::make_error, global, prototype, true)
     }
 
     /// Initialise the global object with the `Error` object.

boa/src/builtins/error/range.rs

@@ -63,9 +63,10 @@ impl RangeError {
     pub(crate) fn create(global: &Value) -> Value {
         let prototype = Value::new_object(Some(global));
         prototype.set_field("message", Value::from(""));
-        prototype.set_field("name", Value::from("RangeError"));
+
         make_builtin_fn(Self::to_string, "toString", &prototype, 0);
-        make_constructor_fn(Self::make_error, global, prototype)
+
+        make_constructor_fn("RangeError", 1, Self::make_error, global, prototype, true)
     }
 
     /// Runs a `new RangeError(message)`.

boa/src/builtins/function/mod.rs

@@ -14,7 +14,7 @@
 use crate::{
     builtins::{
         array::Array,
-        object::{Object, ObjectInternalMethods, ObjectKind, PROTOTYPE},
+        object::{Object, ObjectInternalMethods, ObjectKind, INSTANCE_PROTOTYPE, PROTOTYPE},
         property::Property,
         value::{ResultValue, Value},
     },
@@ -72,18 +72,6 @@ unsafe impl Trace for FunctionBody {
     unsafe_empty_trace!();
 }
 
-/// Signal what sort of function this is
-#[derive(Clone, Debug, Copy, Finalize)]
-pub enum FunctionKind {
-    BuiltIn,
-    Ordinary,
-}
-
-/// Waiting on <https://github.com/Manishearth/rust-gc/issues/87> until we can derive Copy
-unsafe impl Trace for FunctionKind {
-    unsafe_empty_trace!();
-}
-
 /// Boa representation of a Function Object.
 ///
 /// <https://tc39.es/ecma262/#sec-ecmascript-function-objects>
@@ -95,48 +83,73 @@ pub struct Function {
     pub params: Box<[FormalParameter]>,
     /// This Mode
     pub this_mode: ThisMode,
-    /// Function kind
-    pub kind: FunctionKind,
     // Environment, built-in functions don't need Environments
     pub environment: Option<Environment>,
+    /// Is it constructable
+    constructable: bool,
+    /// Is it callable.
+    callable: bool,
 }
 
 impl Function {
-    /// This will create an ordinary function object
-    ///
-    /// <https://tc39.es/ecma262/#sec-ordinaryfunctioncreate>
-    pub fn create_ordinary<P>(
+    pub fn new<P>(
         parameter_list: P,
-        scope: Environment,
+        scope: Option<Environment>,
         body: FunctionBody,
         this_mode: ThisMode,
+        constructable: bool,
+        callable: bool,
     ) -> Self
     where
         P: Into<Box<[FormalParameter]>>,
     {
         Self {
             body,
-            environment: Some(scope),
+            environment: scope,
             params: parameter_list.into(),
-            kind: FunctionKind::Ordinary,
             this_mode,
+            constructable,
+            callable,
         }
     }
 
+    /// This will create an ordinary function object
+    ///
+    /// <https://tc39.es/ecma262/#sec-ordinaryfunctioncreate>
+    pub fn ordinary<P>(
+        parameter_list: P,
+        scope: Environment,
+        body: StatementList,
+        this_mode: ThisMode,
+    ) -> Self
+    where
+        P: Into<Box<[FormalParameter]>>,
+    {
+        Self::new(
+            parameter_list.into(),
+            Some(scope),
+            FunctionBody::Ordinary(body),
+            this_mode,
+            true,
+            true,
+        )
+    }
+
     /// This will create a built-in function object
     ///
     /// <https://tc39.es/ecma262/#sec-createbuiltinfunction>
-    pub fn create_builtin<P>(parameter_list: P, body: FunctionBody) -> Self
+    pub fn builtin<P>(parameter_list: P, body: NativeFunctionData) -> Self
     where
         P: Into<Box<[FormalParameter]>>,
     {
-        Self {
-            body,
-            params: parameter_list.into(),
-            this_mode: ThisMode::NonLexical,
-            kind: FunctionKind::BuiltIn,
-            environment: None,
-        }
+        Self::new(
+            parameter_list.into(),
+            None,
+            FunctionBody::BuiltIn(body),
+            ThisMode::NonLexical,
+            false,
+            true,
+        )
     }
 
     /// This will handle calls for both ordinary and built-in functions
@@ -150,57 +163,53 @@ impl Function {
         interpreter: &mut Interpreter,
         this_obj: &mut Value,
     ) -> ResultValue {
-        match self.kind {
-            FunctionKind::BuiltIn => match &self.body {
+        if self.callable {
+            match self.body {
                 FunctionBody::BuiltIn(func) => func(this_obj, args_list, interpreter),
-                FunctionBody::Ordinary(_) => {
-                    panic!("Builtin function should not have Ordinary Function body")
-                }
-            },
-            FunctionKind::Ordinary => {
-                // Create a new Function environment who's parent is set to the scope of the function declaration (self.environment)
-                // <https://tc39.es/ecma262/#sec-prepareforordinarycall>
-                let local_env = new_function_environment(
-                    this.clone(),
-                    None,
-                    Some(self.environment.as_ref().unwrap().clone()),
-                    BindingStatus::Uninitialized,
-                );
-
-                // Add argument bindings to the function environment
-                for i in 0..self.params.len() {
-                    let param = self.params.get(i).expect("Could not get param");
-                    // Rest Parameters
-                    if param.is_rest_param() {
-                        self.add_rest_param(param, i, args_list, interpreter, &local_env);
-                        break;
+                FunctionBody::Ordinary(ref body) => {
+                    // Create a new Function environment who's parent is set to the scope of the function declaration (self.environment)
+                    // <https://tc39.es/ecma262/#sec-prepareforordinarycall>
+                    let local_env = new_function_environment(
+                        this.clone(),
+                        None,
+                        Some(self.environment.as_ref().unwrap().clone()),
+                        BindingStatus::Uninitialized,
+                    );
+
+                    // Add argument bindings to the function environment
+                    for i in 0..self.params.len() {
+                        let param = self.params.get(i).expect("Could not get param");
+                        // Rest Parameters
+                        if param.is_rest_param() {
+                            self.add_rest_param(param, i, args_list, interpreter, &local_env);
+                            break;
+                        }
+
+                        let value = args_list.get(i).expect("Could not get value");
+                        self.add_arguments_to_environment(param, value.clone(), &local_env);
                     }
 
-                    let value = args_list.get(i).expect("Could not get value");
-                    self.add_arguments_to_environment(param, value.clone(), &local_env);
-                }
+                    // Add arguments object
+                    let arguments_obj = create_unmapped_arguments_object(args_list);
+                    local_env
+                        .borrow_mut()
+                        .create_mutable_binding("arguments".to_string(), false);
+                    local_env
+                        .borrow_mut()
+                        .initialize_binding("arguments", arguments_obj);
+
+                    interpreter.realm.environment.push(local_env);
 
-                // Add arguments object
-                let arguments_obj = create_unmapped_arguments_object(args_list);
-                local_env
-                    .borrow_mut()
-                    .create_mutable_binding("arguments".to_string(), false);
-                local_env
-                    .borrow_mut()
-                    .initialize_binding("arguments", arguments_obj);
-
-                interpreter.realm.environment.push(local_env);
-
-                // Call body should be set before reaching here
-                let result = match &self.body {
-                    FunctionBody::Ordinary(ref body) => body.run(interpreter),
-                    _ => panic!("Ordinary function should not have BuiltIn Function body"),
-                };
-
-                // local_env gets dropped here, its no longer needed
-                interpreter.realm.environment.pop();
-                result
+                    // Call body should be set before reaching here
+                    let result = body.run(interpreter);
+
+                    // local_env gets dropped here, its no longer needed
+                    interpreter.realm.environment.pop();
+                    result
+                }
             }
+        } else {
+            panic!("TypeError: class constructors must be invoked with 'new'");
         }
     }
 
@@ -212,59 +221,56 @@ impl Function {
         interpreter: &mut Interpreter,
         this_obj: &mut Value,
     ) -> ResultValue {
-        match self.kind {
-            FunctionKind::BuiltIn => match &self.body {
+        if self.constructable {
+            match self.body {
                 FunctionBody::BuiltIn(func) => {
                     func(this_obj, args_list, interpreter).unwrap();
                     Ok(this_obj.clone())
                 }
-                FunctionBody::Ordinary(_) => {
-                    panic!("Builtin function should not have Ordinary Function body")
-                }
-            },
-            FunctionKind::Ordinary => {
-                // Create a new Function environment who's parent is set to the scope of the function declaration (self.environment)
-                // <https://tc39.es/ecma262/#sec-prepareforordinarycall>
-                let local_env = new_function_environment(
-                    this.clone(),
-                    Some(this_obj.clone()),
-                    Some(self.environment.as_ref().unwrap().clone()),
-                    BindingStatus::Initialized,
-                );
-
-                // Add argument bindings to the function environment
-                for (i, param) in self.params.iter().enumerate() {
-                    // Rest Parameters
-                    if param.is_rest_param() {
-                        self.add_rest_param(param, i, args_list, interpreter, &local_env);
-                        break;
+                FunctionBody::Ordinary(ref body) => {
+                    // Create a new Function environment who's parent is set to the scope of the function declaration (self.environment)
+                    // <https://tc39.es/ecma262/#sec-prepareforordinarycall>
+                    let local_env = new_function_environment(
+                        this.clone(),
+                        Some(this_obj.clone()),
+                        Some(self.environment.as_ref().unwrap().clone()),
+                        BindingStatus::Initialized,
+                    );
+
+                    // Add argument bindings to the function environment
+                    for (i, param) in self.params.iter().enumerate() {
+                        // Rest Parameters
+                        if param.is_rest_param() {
+                            self.add_rest_param(param, i, args_list, interpreter, &local_env);
+                            break;
+                        }
+
+                        let value = args_list.get(i).expect("Could not get value");
+                        self.add_arguments_to_environment(param, value.clone(), &local_env);
                     }
 
-                    let value = args_list.get(i).expect("Could not get value");
-                    self.add_arguments_to_environment(param, value.clone(), &local_env);
-                }
+                    // Add arguments object
+                    let arguments_obj = create_unmapped_arguments_object(args_list);
+                    local_env
+                        .borrow_mut()
+                        .create_mutable_binding("arguments".to_string(), false);
+                    local_env
+                        .borrow_mut()
+                        .initialize_binding("arguments", arguments_obj);
+
+                    interpreter.realm.environment.push(local_env);
+
+                    // Call body should be set before reaching here
+                    let _ = body.run(interpreter);
 
-                // Add arguments object
-                let arguments_obj = create_unmapped_arguments_object(args_list);
-                local_env
-                    .borrow_mut()
-                    .create_mutable_binding("arguments".to_string(), false);
-                local_env
-                    .borrow_mut()
-                    .initialize_binding("arguments", arguments_obj);
-
-                interpreter.realm.environment.push(local_env);
-
-                // Call body should be set before reaching here
-                let _ = match &self.body {
-                    FunctionBody::Ordinary(ref body) => body.run(interpreter),
-                    _ => panic!("Ordinary function should not have BuiltIn Function body"),
-                };
-
-                // local_env gets dropped here, its no longer needed
-                let binding = interpreter.realm.environment.get_this_binding();
-                Ok(binding)
+                    // local_env gets dropped here, its no longer needed
+                    let binding = interpreter.realm.environment.get_this_binding();
+                    Ok(binding)
+                }
             }
+        } else {
+            let name = this.get_field("name").to_string();
+            panic!("TypeError: {} is not a constructor", name);
         }
     }
 
@@ -309,6 +315,16 @@ impl Function {
             .borrow_mut()
             .initialize_binding(param.name(), value);
     }
+
+    /// Returns true if the function object is callable.
+    pub fn is_callable(&self) -> bool {
+        self.callable
+    }
+
+    /// Returns true if the function object is constructable.
+    pub fn is_constructable(&self) -> bool {
+        self.constructable
+    }
 }
 
 impl Debug for Function {
@@ -319,16 +335,6 @@ impl Debug for Function {
     }
 }
 
-/// Function Prototype.
-///
-/// <https://tc39.es/ecma262/#sec-properties-of-the-function-prototype-object>
-pub fn create_function_prototype() {
-    let mut function_prototype: Object = Object::default();
-    // Set Kind to function (for historical & compatibility reasons)
-    // <https://tc39.es/ecma262/#sec-properties-of-the-function-prototype-object>
-    function_prototype.kind = ObjectKind::Function;
-}
-
 /// Arguments.
 ///
 /// <https://tc39.es/ecma262/#sec-createunmappedargumentsobject>
@@ -369,19 +375,25 @@ pub fn make_function(this: &mut Value, _: &[Value], _: &mut Interpreter) -> Resu
 pub fn create(global: &Value) -> Value {
     let prototype = Value::new_object(Some(global));
 
-    make_constructor_fn(make_function, global, prototype)
+    make_constructor_fn("Function", 1, make_function, global, prototype, true)
 }
 
 /// Creates a new constructor function
 ///
 /// This utility function handling linking the new Constructor to the prototype.
 /// So far this is only used by internal functions
-pub fn make_constructor_fn(body: NativeFunctionData, global: &Value, proto: Value) -> Value {
+pub fn make_constructor_fn(
+    name: &str,
+    length: i32,
+    body: NativeFunctionData,
+    global: &Value,
+    proto: Value,
+    constructable: bool,
+) -> Value {
     // Create the native function
-    let constructor_fn = crate::builtins::function::Function::create_builtin(
-        vec![],
-        crate::builtins::function::FunctionBody::BuiltIn(body),
-    );
+    let mut constructor_fn = Function::builtin(Vec::new(), body);
+
+    constructor_fn.constructable = constructable;
 
     // Get reference to Function.prototype
     let func_prototype = global.get_field("Function").get_field(PROTOTYPE);
@@ -390,13 +402,27 @@ pub fn make_constructor_fn(body: NativeFunctionData, global: &Value, proto: Valu
     let mut constructor_obj = Object::function();
     constructor_obj.set_func(constructor_fn);
 
-    constructor_obj.set_internal_slot("__proto__", func_prototype);
+    constructor_obj.set_internal_slot(INSTANCE_PROTOTYPE, func_prototype);
     let constructor_val = Value::from(constructor_obj);
 
     // Set proto.constructor -> constructor_obj
     proto.set_field("constructor", constructor_val.clone());
     constructor_val.set_field(PROTOTYPE, proto);
 
+    let length = Property::new()
+        .value(Value::from(length))
+        .writable(false)
+        .configurable(false)
+        .enumerable(false);
+    constructor_val.set_property_slice("length", length);
+
+    let name = Property::new()
+        .value(Value::from(name))
+        .writable(false)
+        .configurable(false)
+        .enumerable(false);
+    constructor_val.set_property_slice("name", name);
+
     constructor_val
 }
 
@@ -407,7 +433,7 @@ pub fn make_builtin_fn<N>(function: NativeFunctionData, name: N, parent: &Value,
 where
     N: Into<String>,
 {
-    let func = Function::create_builtin(vec![], FunctionBody::BuiltIn(function));
+    let func = Function::builtin(Vec::new(), function);
 
     let mut new_func = Object::function();
     new_func.set_func(func);

boa/src/builtins/mod.rs

@@ -1,4 +1,4 @@
-//! Builtins live here, such as Object, String, Math etc
+//! Builtins live here, such as Object, String, Math, etc.
 
 pub mod array;
 pub mod bigint;

boa/src/builtins/number/mod.rs

@@ -89,21 +89,6 @@ impl Number {
         Ok(data)
     }
 
-    /// `Number()` function.
-    ///
-    /// More Information https://tc39.es/ecma262/#sec-number-constructor-number-value
-    pub(crate) fn call_number(
-        _this: &mut Value,
-        args: &[Value],
-        _ctx: &mut Interpreter,
-    ) -> ResultValue {
-        let data = match args.get(0) {
-            Some(ref value) => Self::to_number(value),
-            None => Self::to_number(&Value::from(0)),
-        };
-        Ok(data)
-    }
-
     /// `Number.prototype.toExponential( [fractionDigits] )`
     ///
     /// The `toExponential()` method returns a string representing the Number object in exponential notation.
@@ -417,7 +402,7 @@ impl Number {
         make_builtin_fn(Self::to_string, "toString", &prototype, 1);
         make_builtin_fn(Self::value_of, "valueOf", &prototype, 0);
 
-        make_constructor_fn(Self::make_number, global, prototype)
+        make_constructor_fn("Number", 1, Self::make_number, global, prototype, true)
     }
 
     /// Initialise the `Number` object on the global object.

boa/src/builtins/object/mod.rs

@@ -471,7 +471,10 @@ impl Object {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-iscallable
     pub fn is_callable(&self) -> bool {
-        self.func.is_some()
+        match self.func {
+            Some(ref function) => function.is_callable(),
+            None => false,
+        }
     }
 
     /// It determines if Object is a function object with a [[Construct]] internal method.
@@ -480,8 +483,11 @@ impl Object {
     /// - [EcmaScript reference][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-isconstructor
-    pub fn is_constructor(&self) -> bool {
-        self.func.is_some()
+    pub fn is_constructable(&self) -> bool {
+        match self.func {
+            Some(ref function) => function.is_constructable(),
+            None => false,
+        }
     }
 }
 
@@ -614,7 +620,7 @@ pub fn create(global: &Value) -> Value {
     make_builtin_fn(has_own_property, "hasOwnProperty", &prototype, 0);
     make_builtin_fn(to_string, "toString", &prototype, 0);
 
-    let object = make_constructor_fn(make_object, global, prototype);
+    let object = make_constructor_fn("Object", 1, make_object, global, prototype, true);
 
     object.set_field("length", Value::from(1));
     make_builtin_fn(set_prototype_of, "setPrototypeOf", &object, 2);

boa/src/builtins/regexp/mod.rs

@@ -485,7 +485,7 @@ impl RegExp {
         make_builtin_fn(Self::get_sticky, "sticky", &prototype, 0);
         make_builtin_fn(Self::get_unicode, "unicode", &prototype, 0);
 
-        make_constructor_fn(Self::make_regexp, global, prototype)
+        make_constructor_fn("RegExp", 1, Self::make_regexp, global, prototype, true)
     }
 
     /// Initialise the `RegExp` object on the global object.

boa/src/builtins/string/mod.rs

@@ -1071,7 +1071,7 @@ impl String {
         make_builtin_fn(Self::match_all, "matchAll", &prototype, 1);
         make_builtin_fn(Self::replace, "replace", &prototype, 2);
 
-        make_constructor_fn(Self::make_string, global, prototype)
+        make_constructor_fn("String", 1, Self::make_string, global, prototype, true)
     }
 
     /// Initialise the `String` object on the global object.

boa/src/builtins/symbol/mod.rs

@@ -92,8 +92,9 @@ pub fn to_string(this: &mut Value, _: &[Value], _: &mut Interpreter) -> ResultVa
 pub fn create(global: &Value) -> Value {
     // Create prototype object
     let prototype = Value::new_object(Some(global));
+
     make_builtin_fn(to_string, "toString", &prototype, 0);
-    make_constructor_fn(call_symbol, global, prototype)
+    make_constructor_fn("Symbol", 1, call_symbol, global, prototype, false)
 }
 
 /// Initialise the `Symbol` object on the global object.

boa/src/builtins/value/mod.rs

@@ -217,7 +217,7 @@ impl ValueData {
         match *self {
             Self::Object(ref o) => {
                 let borrowed_obj = o.borrow();
-                borrowed_obj.is_callable() || borrowed_obj.is_constructor()
+                borrowed_obj.is_callable() || borrowed_obj.is_constructable()
             }
             _ => false,
         }

boa/src/exec/declaration/mod.rs

@@ -18,6 +18,8 @@ impl Executable for FunctionDecl {
             self.parameters().to_vec(),
             self.body().to_vec(),
             ThisMode::NonLexical,
+            true,
+            true,
         );
 
         // Set the name and assign it in the current environment
@@ -43,6 +45,8 @@ impl Executable for FunctionExpr {
             self.parameters().to_vec(),
             self.body().to_vec(),
             ThisMode::NonLexical,
+            true,
+            true,
         );
 
         if let Some(name) = self.name() {
@@ -125,6 +129,8 @@ impl Executable for ArrowFunctionDecl {
             self.params().to_vec(),
             self.body().to_vec(),
             ThisMode::Lexical,
+            false,
+            true,
         ))
     }
 }

boa/src/exec/mod.rs

@@ -58,7 +58,14 @@ impl Interpreter {
     }
 
     /// Utility to create a function Value for Function Declarations, Arrow Functions or Function Expressions
-    pub(crate) fn create_function<P, B>(&mut self, params: P, body: B, this_mode: ThisMode) -> Value
+    pub(crate) fn create_function<P, B>(
+        &mut self,
+        params: P,
+        body: B,
+        this_mode: ThisMode,
+        constructable: bool,
+        callable: bool,
+    ) -> Value
     where
         P: Into<Box<[FormalParameter]>>,
         B: Into<StatementList>,
@@ -69,7 +76,7 @@ impl Interpreter {
             .get_global_object()
             .expect("Could not get the global object")
             .get_field("Function")
-            .get_field("Prototype");
+            .get_field(PROTOTYPE);
 
         // Every new function has a prototype property pre-made
         let global_val = &self
@@ -81,11 +88,13 @@ impl Interpreter {
 
         let params = params.into();
         let params_len = params.len();
-        let func = FunctionObject::create_ordinary(
+        let func = FunctionObject::new(
             params,
-            self.realm.environment.get_current_environment().clone(),
+            Some(self.realm.environment.get_current_environment().clone()),
             FunctionBody::Ordinary(body.into()),
             this_mode,
+            constructable,
+            callable,
         );
 
         let mut new_func = Object::function();

boa/src/realm.rs

@@ -7,7 +7,7 @@
 use crate::{
     builtins::{
         self,
-        function::NativeFunctionData,
+        function::{Function, NativeFunctionData},
         value::{Value, ValueData},
     },
     environment::{
@@ -60,10 +60,7 @@ impl Realm {
 
     /// Utility to add a function to the global object
     pub fn register_global_func(self, func_name: &str, func: NativeFunctionData) -> Self {
-        let func = crate::builtins::function::Function::create_builtin(
-            vec![],
-            crate::builtins::function::FunctionBody::BuiltIn(func),
-        );
+        let func = Function::builtin(Vec::new(), func);
         self.global_obj
             .set_field(Value::from(func_name), ValueData::from_func(func));