// Copyright (C) 2016 the V8 project authors. All rights reserved. // This code is governed by the BSD license found in the LICENSE file. /*--- esid: sec-addition-operator-plus-runtime-semantics-evaluation es6id: 12.7.3.1 description: Invocation of `Symbol.toPrimitive` method during coercion info: | [...] 5. Let lprim be ? ToPrimitive(lval). 6. Let rprim be ? ToPrimitive(rval). [...] ES6 Section 7.2.12 Abstract Equality Comparison [...] 10. If Type(x) is either String, Number, or Symbol and Type(y) is Object, then return the result of the comparison x == ToPrimitive(y). ES6 Section 7.1.1 ToPrimitive ( input [, PreferredType] ) 1. If PreferredType was not passed, let hint be "default". [...] 4. Let exoticToPrim be GetMethod(input, @@toPrimitive). 5. ReturnIfAbrupt(exoticToPrim). 6. If exoticToPrim is not undefined, then a. Let result be Call(exoticToPrim, input, «hint»). [...] features: [Symbol.toPrimitive] ---*/ var left = {}; var right = {}; var log = ''; var leftThisVal, rightThisVal, leftArgs, rightArgs; left[Symbol.toPrimitive] = function() { log += 'left'; leftThisVal = this; leftArgs = arguments; }; right[Symbol.toPrimitive] = function() { log += 'right'; rightThisVal = this; rightArgs = arguments; }; left + right; assert.sameValue(log, 'leftright', 'methods invoked in correct sequence'); assert.sameValue(leftThisVal, left, 'left-hand side `this` value'); assert.sameValue(leftArgs.length, 1, 'left-hand side argument length'); assert.sameValue(leftArgs[0], 'default', 'left-hand side argument value'); assert.sameValue(rightThisVal, right, 'right-hand side `this` value'); assert.sameValue(rightArgs.length, 1, 'right-hand side argument length'); assert.sameValue(rightArgs[0], 'default', 'right-hand side argument value');