LibJS: Don't use null DFS for binding_name parameters in ClassExpression

Userland/Libraries/LibJS/AST.cpp

@@ -293,7 +293,7 @@ ThrowCompletionOr<ClassElement::ClassValue> StaticInitializer::class_element_eva
     return ClassValue { normal_completion(body_function) };
 }
 
-ThrowCompletionOr<ECMAScriptFunctionObject*> ClassExpression::create_class_constructor(VM& vm, Environment* class_environment, Environment* environment, Value super_class, DeprecatedFlyString const& binding_name, DeprecatedFlyString const& class_name) const
+ThrowCompletionOr<ECMAScriptFunctionObject*> ClassExpression::create_class_constructor(VM& vm, Environment* class_environment, Environment* environment, Value super_class, Optional<DeprecatedFlyString> const& binding_name, DeprecatedFlyString const& class_name) const
 {
     auto& realm = *vm.current_realm();
 
@@ -421,8 +421,8 @@ ThrowCompletionOr<ECMAScriptFunctionObject*> ClassExpression::create_class_const
     vm.running_execution_context().lexical_environment = environment;
     restore_environment.disarm();
 
-    if (!binding_name.is_null())
-        MUST(class_environment->initialize_binding(vm, binding_name, class_constructor, Environment::InitializeBindingHint::Normal));
+    if (binding_name.has_value())
+        MUST(class_environment->initialize_binding(vm, binding_name.value(), class_constructor, Environment::InitializeBindingHint::Normal));
 
     for (auto& field : instance_fields)
         class_constructor->add_field(field);
@@ -451,7 +451,7 @@ ThrowCompletionOr<ECMAScriptFunctionObject*> ClassExpression::create_class_const
     return { class_constructor };
 }
 
-ThrowCompletionOr<ECMAScriptFunctionObject*> ClassExpression::class_definition_evaluation(VM& vm, DeprecatedFlyString const& binding_name, DeprecatedFlyString const& class_name) const
+ThrowCompletionOr<ECMAScriptFunctionObject*> ClassExpression::class_definition_evaluation(VM& vm, Optional<DeprecatedFlyString> const& binding_name, DeprecatedFlyString const& class_name) const
 {
     auto* environment = vm.lexical_environment();
     VERIFY(environment);
@@ -459,8 +459,8 @@ ThrowCompletionOr<ECMAScriptFunctionObject*> ClassExpression::class_definition_e
 
     Value super_class;
 
-    if (!binding_name.is_null())
-        MUST(class_environment->create_immutable_binding(vm, binding_name, true));
+    if (binding_name.has_value())
+        MUST(class_environment->create_immutable_binding(vm, binding_name.value(), true));
 
     if (!m_super_class.is_null()) {
         vm.running_execution_context().lexical_environment = class_environment;

Userland/Libraries/LibJS/AST.h

@@ -1418,8 +1418,8 @@ public:
 
     bool has_name() const { return m_name; }
 
-    ThrowCompletionOr<ECMAScriptFunctionObject*> class_definition_evaluation(VM&, DeprecatedFlyString const& binding_name = {}, DeprecatedFlyString const& class_name = {}) const;
-    ThrowCompletionOr<ECMAScriptFunctionObject*> create_class_constructor(VM&, Environment* class_environment, Environment* environment, Value super_class, DeprecatedFlyString const& binding_name = {}, DeprecatedFlyString const& class_name = {}) const;
+    ThrowCompletionOr<ECMAScriptFunctionObject*> class_definition_evaluation(VM&, Optional<DeprecatedFlyString> const& binding_name = {}, DeprecatedFlyString const& class_name = {}) const;
+    ThrowCompletionOr<ECMAScriptFunctionObject*> create_class_constructor(VM&, Environment* class_environment, Environment* environment, Value super_class, Optional<DeprecatedFlyString> const& binding_name = {}, DeprecatedFlyString const& class_name = {}) const;
 
 private:
     virtual bool is_class_expression() const override { return true; }

Userland/Libraries/LibJS/Bytecode/CommonImplementations.h

@@ -611,7 +611,7 @@ inline ThrowCompletionOr<ECMAScriptFunctionObject*> new_class(VM& vm, Value supe
     auto* class_environment = vm.lexical_environment();
     vm.running_execution_context().lexical_environment = interpreter.saved_lexical_environment_stack().take_last();
 
-    DeprecatedFlyString binding_name;
+    Optional<DeprecatedFlyString> binding_name;
     DeprecatedFlyString class_name;
     if (!class_expression.has_name() && lhs_name.has_value()) {
         class_name = interpreter.current_executable().get_identifier(lhs_name.value());