| // Copyright (C) 2020 Rick Waldron. All rights reserved. |
| // This code is governed by the BSD license found in the LICENSE file. |
| |
| /*--- |
| esid: sec-object-environment-records-setmutablebinding-n-v-s |
| description: > |
| Operator --x calls PutValue(lhs, newValue) (formerly S11.4.5_A5_T5) |
| info: | |
| The concrete Environment Record method SetMutableBinding for object Environment |
| Records attempts to set the value of the Environment Record's associated binding |
| object's property whose name is the value of the argument N to the value of argument V. |
| A property named N normally already exists but if it does not or is not currently writable, |
| error handling is determined by the value of the Boolean argument S. |
| |
| Let stillExists be ? HasProperty(bindings, N). |
| If stillExists is false and S is true, throw a ReferenceError exception. |
| flags: [noStrict] |
| ---*/ |
| var count = 0; |
| Object.defineProperty(this, "x", { |
| configurable: true, |
| get: function() { |
| delete this.x; |
| return 2; |
| } |
| }); |
| |
| (function() { |
| "use strict"; |
| assert.throws(ReferenceError, () => { |
| count++; |
| --x; |
| count++; |
| }); |
| count++; |
| })(); |
| |
| assert.sameValue(count, 2); |
| assert(!('x' in this)); |