JSTests/test262/test/language/expressions/equals/coerce-symbol-to-prim-err.js

// Copyright (C) 2015 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
es6id: 12.10.3
description: >
    Behavior when error thrown by invocation of `Symbol.toPrimitive` method
    during coercion
info: |
    [...]
    7. Return the result of performing Abstract Equality Comparison rval ==
       lval.

    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] )

    [...]
    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»).
       b. ReturnIfAbrupt(result).
features: [Symbol.toPrimitive]
---*/

var y = {};
y[Symbol.toPrimitive] = function() {
  throw new Test262Error();
};

assert.throws(Test262Error, function() {
  0 == y;
});