v8/test/message/fail/destructuring-undefined-number-property.js

// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

var { 1: x } = undefined;
[parser] Better error message when destructuring against undefined/null Previously, when destructuring against null or undefined we would print: d8> var { x } = null (d8):1: TypeError: Cannot match against 'undefined' or 'null'. var { x } = null ^ TypeError: Cannot match against 'undefined' or 'null'. at (d8):1:1 The above message uses the term "match" which isn't a common term in JavaScript to describe destructuring. This message also doesn't provide the name of the property that fails destructuring. This patch changes the error message to be: d8> var { x } = null; (d8):1: TypeError: Cannot destructure property `x` of 'undefined' or 'null'. var { x } = null; ^ TypeError: Cannot destructure property `x` of 'undefined' or 'null'. at (d8):1:1 This patch changes the message to say "destructure" instead of "match". This patch adds support for printing property names that are string literals. We iterate through every property and pick the first string literal property name if it exists. This provides at least some feedback to the developer. This patch also makes the pointer point to the position of the property name that fails destructuring. For computed and numeric property names, we print a generic error: d8> var { 1: x } = null (d8):1: TypeError: Cannot destructure against 'undefined' or 'null'. var { 1: x } = null ^ TypeError: Cannot destructure against 'undefined' or 'null'. at (d8):1:1 Bug: v8:6499 Change-Id: I35b1ac749489828686f042975294b9926e2dfc53 Reviewed-on: https://chromium-review.googlesource.com/537341 Reviewed-by: Adam Klein <adamk@chromium.org> Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org> Cr-Commit-Position: refs/heads/master@{#45965} 2017-06-15 21:24:37 +00:00			`// Copyright 2017 the V8 project authors. All rights reserved.`
			`// Use of this source code is governed by a BSD-style license that can be`
			`// found in the LICENSE file.`

			`var { 1: x } = undefined;`