LibJS: Throw real TypeError, ReferenceError, etc objects

Instead of just throwing Error objects with a name string, we now throw
the real Error subclass types. :^)

Libraries/LibJS/AST.cpp

@@ -97,11 +97,11 @@ Value CallExpression::execute(Interpreter& interpreter) const
             || !callee.as_object().is_function()
             || (callee.as_object().is_native_function()
                 && !static_cast<NativeFunction&>(callee.as_object()).has_constructor()))
-            return interpreter.throw_exception<Error>("TypeError", String::format("%s is not a constructor", callee.to_string().characters()));
+            return interpreter.throw_exception<TypeError>(String::format("%s is not a constructor", callee.to_string().characters()));
     }
 
     if (!callee.is_object() || !callee.as_object().is_function())
-        return interpreter.throw_exception<Error>("TypeError", String::format("%s is not a function", callee.to_string().characters()));
+        return interpreter.throw_exception<TypeError>(String::format("%s is not a function", callee.to_string().characters()));
 
     auto& function = static_cast<Function&>(callee.as_object());
 
@@ -651,7 +651,7 @@ Value Identifier::execute(Interpreter& interpreter) const
 {
     auto variable = interpreter.get_variable(string());
     if (!variable.has_value())
-        return interpreter.throw_exception<Error>("ReferenceError", String::format("'%s' not known", string().characters()));
+        return interpreter.throw_exception<ReferenceError>(String::format("'%s' not known", string().characters()));
     return variable.value();
 }
 
@@ -711,7 +711,7 @@ Value AssignmentExpression::execute(Interpreter& interpreter) const
             object->put(property_name, rhs_result);
         }
     } else {
-        return interpreter.throw_exception<Error>("ReferenceError", "Invalid left-hand side in assignment");
+        return interpreter.throw_exception<ReferenceError>("Invalid left-hand side in assignment");
     }
 
     return rhs_result;

Libraries/LibJS/Heap/Heap.cpp

@@ -41,7 +41,7 @@
 #endif
 
 #ifdef __serenity__
-#define HEAP_DEBUG
+//#define HEAP_DEBUG
 #endif
 
 namespace JS {

Libraries/LibJS/Runtime/Array.cpp

@@ -66,7 +66,7 @@ Value Array::length_getter(Interpreter& interpreter)
     if (!this_object)
         return {};
     if (!this_object->is_array())
-        return interpreter.throw_exception<Error>("TypeError", "Not an array");
+        return interpreter.throw_exception<TypeError>("Not an array");
     return Value(static_cast<const Array*>(this_object)->length());
 }
 

Libraries/LibJS/Runtime/ArrayPrototype.cpp

@@ -54,7 +54,7 @@ static Array* array_from(Interpreter& interpreter)
     if (!this_object)
         return {};
     if (!this_object->is_array()) {
-        interpreter.throw_exception<Error>("TypeError", "Not an Array");
+        interpreter.throw_exception<TypeError>("Not an Array");
         return nullptr;
     }
     return static_cast<Array*>(this_object);

Libraries/LibJS/Runtime/BooleanPrototype.cpp

@@ -47,7 +47,7 @@ Value BooleanPrototype::to_string(Interpreter& interpreter)
         return js_string(interpreter.heap(), this_object.as_bool() ? "true" : "false");
     }
     if (!this_object.is_object() || !this_object.as_object().is_boolean()) {
-        interpreter.throw_exception<Error>("TypeError", "Not a Boolean");
+        interpreter.throw_exception<TypeError>("Not a Boolean");
         return {};
     }
 
@@ -62,7 +62,7 @@ Value BooleanPrototype::value_of(Interpreter& interpreter)
         return this_object;
     }
     if (!this_object.is_object() || !this_object.as_object().is_boolean()) {
-        interpreter.throw_exception<Error>("TypeError", "Not a Boolean");
+        interpreter.throw_exception<TypeError>("Not a Boolean");
         return {};
     }
 

Libraries/LibJS/Runtime/DatePrototype.cpp

@@ -41,7 +41,7 @@ static Date* this_date_from_interpreter(Interpreter& interpreter)
     if (!this_object)
         return nullptr;
     if (!this_object->is_date()) {
-        interpreter.throw_exception<Error>("TypeError", "object must be of type Date");
+        interpreter.throw_exception<TypeError>("object must be of type Date");
         return nullptr;
     }
     return static_cast<Date*>(this_object);

Libraries/LibJS/Runtime/ErrorPrototype.cpp

@@ -51,7 +51,7 @@ Value ErrorPrototype::name_getter(Interpreter& interpreter)
     if (!this_object)
         return {};
     if (!this_object->is_error())
-        return interpreter.throw_exception<Error>("TypeError", "Not an Error object");
+        return interpreter.throw_exception<TypeError>("Not an Error object");
     return js_string(interpreter, static_cast<const Error*>(this_object)->name());
 }
 
@@ -61,14 +61,14 @@ Value ErrorPrototype::message_getter(Interpreter& interpreter)
     if (!this_object)
         return {};
     if (!this_object->is_error())
-        return interpreter.throw_exception<Error>("TypeError", "Not an Error object");
+        return interpreter.throw_exception<TypeError>("Not an Error object");
     return js_string(interpreter, static_cast<const Error*>(this_object)->message());
 }
 
 Value ErrorPrototype::to_string(Interpreter& interpreter)
 {
     if (!interpreter.this_value().is_object())
-        return interpreter.throw_exception<Error>("TypeError", "Not an object");
+        return interpreter.throw_exception<TypeError>("Not an object");
     auto& this_object = interpreter.this_value().as_object();
 
     String name = "Error";
@@ -89,7 +89,10 @@ Value ErrorPrototype::to_string(Interpreter& interpreter)
 }
 
 #define DEFINE_ERROR_SUBCLASS_PROTOTYPE(TitleCase, snake_case) \
-    TitleCase::TitleCase() {}                                  \
+    TitleCase::TitleCase()                                     \
+    {                                                          \
+        set_prototype(interpreter().error_prototype());        \
+    }                                                          \
     TitleCase::~TitleCase() {}                                 \
     const char* TitleCase::class_name() const { return #TitleCase; }
 

Libraries/LibJS/Runtime/FunctionPrototype.cpp

@@ -54,14 +54,14 @@ Value FunctionPrototype::apply(Interpreter& interpreter)
     if (!this_object)
         return {};
     if (!this_object->is_function())
-        return interpreter.throw_exception<Error>("TypeError", "Not a Function object");
+        return interpreter.throw_exception<TypeError>("Not a Function object");
     auto function = static_cast<Function*>(this_object);
     auto this_arg = interpreter.argument(0);
     auto arg_array = interpreter.argument(1);
     if (arg_array.is_null() || arg_array.is_undefined())
         return interpreter.call(function, this_arg);
     if (!arg_array.is_object())
-        return interpreter.throw_exception<Error>("TypeError", "argument array must be an object");
+        return interpreter.throw_exception<TypeError>("argument array must be an object");
     size_t length = 0;
     auto length_property = arg_array.as_object().get("length");
     if (length_property.has_value())
@@ -87,7 +87,7 @@ Value FunctionPrototype::call(Interpreter& interpreter)
     if (!this_object)
         return {};
     if (!this_object->is_function())
-        return interpreter.throw_exception<Error>("TypeError", "Not a Function object");
+        return interpreter.throw_exception<TypeError>("Not a Function object");
     auto function = static_cast<Function*>(this_object);
     auto this_arg = interpreter.argument(0);
     Vector<Value> arguments;
@@ -104,7 +104,7 @@ Value FunctionPrototype::to_string(Interpreter& interpreter)
     if (!this_object)
         return {};
     if (!this_object->is_function())
-        return interpreter.throw_exception<Error>("TypeError", "Not a Function object");
+        return interpreter.throw_exception<TypeError>("Not a Function object");
     // FIXME: Functions should be able to know their name, if any
     if (this_object->is_native_function()) {
         auto function_source = String::format("function () {\n  [%s]\n}", this_object->class_name());

Libraries/LibJS/Runtime/Object.cpp

@@ -110,7 +110,7 @@ void Object::put_own_property(Object& this_object, const FlyString& property_nam
 
     if (mode == PutOwnPropertyMode::DefineProperty && !(metadata.value().attributes & Attribute::Configurable) && attributes != metadata.value().attributes) {
         dbg() << "Disallow reconfig of non-configurable property";
-        interpreter().throw_exception<Error>("TypeError", String::format("Cannot redefine property '%s'", property_name.characters()));
+        interpreter().throw_exception<TypeError>(String::format("Cannot redefine property '%s'", property_name.characters()));
         return;
     }
 

Libraries/LibJS/Runtime/ObjectConstructor.cpp

@@ -101,9 +101,9 @@ Value ObjectConstructor::set_prototype_of(Interpreter& interpreter)
 Value ObjectConstructor::get_own_property_descriptor(Interpreter& interpreter)
 {
     if (interpreter.argument_count() < 2)
-        return interpreter.throw_exception<Error>("TypeError", "Object.getOwnPropertyDescriptor() needs 2 arguments");
+        return interpreter.throw_exception<TypeError>("Object.getOwnPropertyDescriptor() needs 2 arguments");
     if (!interpreter.argument(0).is_object())
-        return interpreter.throw_exception<Error>("TypeError", "Object argument is not an object");
+        return interpreter.throw_exception<TypeError>("Object argument is not an object");
     auto& object = interpreter.argument(0).as_object();
     auto metadata = object.shape().lookup(interpreter.argument(1).to_string());
     if (!metadata.has_value())
@@ -119,11 +119,11 @@ Value ObjectConstructor::get_own_property_descriptor(Interpreter& interpreter)
 Value ObjectConstructor::define_property(Interpreter& interpreter)
 {
     if (interpreter.argument_count() < 3)
-        return interpreter.throw_exception<Error>("TypeError", "Object.defineProperty() needs 3 arguments");
+        return interpreter.throw_exception<TypeError>("Object.defineProperty() needs 3 arguments");
     if (!interpreter.argument(0).is_object())
-        return interpreter.throw_exception<Error>("TypeError", "Object argument is not an object");
+        return interpreter.throw_exception<TypeError>("Object argument is not an object");
     if (!interpreter.argument(2).is_object())
-        return interpreter.throw_exception<Error>("TypeError", "Descriptor argument is not an object");
+        return interpreter.throw_exception<TypeError>("Descriptor argument is not an object");
     auto& object = interpreter.argument(0).as_object();
     auto& descriptor = interpreter.argument(2).as_object();
 

Libraries/LibJS/Runtime/ScriptFunction.cpp

@@ -70,7 +70,7 @@ Value ScriptFunction::length_getter(Interpreter& interpreter)
     if (!this_object)
         return {};
     if (!this_object->is_function())
-        return interpreter.throw_exception<Error>("TypeError", "Not a function");
+        return interpreter.throw_exception<TypeError>("Not a function");
     return Value(static_cast<i32>(static_cast<const ScriptFunction*>(this_object)->parameters().size()));
 }
 

Libraries/LibJS/Runtime/StringPrototype.cpp

@@ -120,7 +120,7 @@ Value StringPrototype::index_of(Interpreter& interpreter)
     if (!this_object)
         return {};
     if (!this_object->is_string_object())
-        return interpreter.throw_exception<Error>("TypeError", "Not a String object");
+        return interpreter.throw_exception<TypeError>("Not a String object");
 
     Value needle_value = js_undefined();
     if (interpreter.argument_count() >= 1)
@@ -141,7 +141,7 @@ static StringObject* string_object_from(Interpreter& interpreter)
     if (!this_object)
         return nullptr;
     if (!this_object->is_string_object()) {
-        interpreter.throw_exception<Error>("TypeError", "Not a String object");
+        interpreter.throw_exception<TypeError>("Not a String object");
         return nullptr;
     }
     return static_cast<StringObject*>(this_object);
@@ -169,7 +169,7 @@ Value StringPrototype::length_getter(Interpreter& interpreter)
     if (!this_object)
         return {};
     if (!this_object->is_string_object())
-        return interpreter.throw_exception<Error>("TypeError", "Not a String object");
+        return interpreter.throw_exception<TypeError>("Not a String object");
     return Value((i32) static_cast<const StringObject*>(this_object)->primitive_string()->string().length());
 }
 

Libraries/LibJS/Runtime/Value.cpp

@@ -115,7 +115,7 @@ Object* Value::to_object(Heap& heap) const
         return heap.allocate<BooleanObject>(m_value.as_bool);
 
     if (is_null() || is_undefined()) {
-        heap.interpreter().throw_exception<Error>("TypeError", "ToObject on null or undefined.");
+        heap.interpreter().throw_exception<TypeError>("ToObject on null or undefined.");
         return nullptr;
     }