Bug 190140 – Incorrect "name" property set for class expression without BindingIdentifier

• Status: NEW
• Component: JavaScriptCore

The "name" property in the constructor function for an anonymous class expression is incorrectly set to an empty string in JavaScriptCore:

// Webkit/JavaScriptCore
(class {}).hasOwnProperty('name') // true
(class extends (class A{}){}).hasOwnProperty('name') // true
(class extends(class A{}){}).name // ''
 
// Other spec-compliant JS engines
(class {}).hasOwnProperty('name') // false
(class extends (class A{}){}).hasOwnProperty('name') // false
(class extends(class A{}){}).name // 'A'

The ES6 spec states that SetFunctionName(value, className) should only be called when className is not undefined, which isn't the case for anonymous class expressions: http://www.ecma-international.org/ecma-262/6.0/#sec-class-definitions-runtime-semantics-evaluation