| // Copyright (C) 2017 Valerie Young. All rights reserved. |
| // This code is governed by the BSD license found in the LICENSE file. |
| |
| /*--- |
| description: Class construction should error if attempting to add private field twice |
| esid: sec-ecmascript-function-objects-construct-argumentslist-newtarget |
| info: | |
| [[Construct]] ( argumentsList, newTarget) |
| ... |
| 8. If kind is "base", then |
| a. Perform OrdinaryCallBindThis(F, calleeContext, thisArgument). |
| b. Let result be InitializeInstanceFields(thisArgument, F). |
| c. If result is an abrupt completion, then |
| i. Remove calleeContext from execution context stack and restore callerContext as the running execution context. |
| ii. Return Completion(result). |
| |
| InitializeInstanceFields ( O, constructor ) |
| 1. Assert: Type ( O ) is Object. |
| 2. Assert: Assert constructor is an ECMAScript function object. |
| 3. Let fieldRecords be the value of constructor's [[Fields]] internal slot. |
| 4. For each item fieldRecord in order from fieldRecords, |
| a. Perform ? DefineField(O, fieldRecord). |
| 5. Return. |
| |
| DefineField(receiver, fieldRecord) |
| ... |
| 8. If fieldName is a Private Name, |
| a. Perform ? PrivateFieldAdd(fieldName, receiver, initValue). |
| |
| PrivateFieldAdd (P, O, value) |
| 1. Assert: P is a Private Name value. |
| 2. If O is not an object, throw a TypeError exception. |
| 3. Let entry be PrivateFieldFind(P, O). |
| 4. If entry is not empty, throw a TypeError exception. |
| ... |
| |
| features: [class, class-fields-private] |
| ---*/ |
| |
| |
| class A { |
| constructor(arg) { |
| return arg; |
| } |
| } |
| |
| class C extends A { |
| #x; |
| |
| constructor(arg) { |
| super(arg); |
| } |
| } |
| |
| var containsprivatex = new C(); |
| |
| assert.throws(TypeError, function() { |
| // After the super call in C's constructor, the `this` value in C will |
| // already have "#x" in it's [[PrivateFieldValues]] |
| new C(containsprivatex); |
| }) |