mapped-unmapped-args.js

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// An unmapped arguments object is created for strict functions or functions

// with default/rest/destructuring args.

load(libdir + "asserts.js");

function testDefaults(a, b=3) {

    a = 3;

    b = 4;

    assertEq(arguments.length, 1);

    assertEq(arguments[0], 1);

    assertEq(arguments[1], undefined);

    arguments[0] = 5;

    assertEq(a, 3);

    assertThrowsInstanceOf(() => arguments.callee, TypeError);

testDefaults(1);

function testRest(a, ...rest) {

    a = 3;

    assertEq(arguments.length, 3);

    assertEq(arguments[0], 1);

    assertEq(arguments[1], 2);

    arguments[0] = 5;

    assertEq(a, 3);

    arguments[1] = 6;

    assertEq(arguments[1], 6);

    assertEq(rest.toString(), "2,3");

    assertThrowsInstanceOf(() => arguments.callee, TypeError);

testRest(1, 2, 3);

function testDestructuring(a, {foo, bar}, b) {

    a = 3;

    bar = 4;

    b = 1;

    assertEq(arguments.length, 3);

    assertEq(arguments[0], 1);

    assertEq(arguments[1].bar, 2);

    assertEq(arguments[2], 9);

    assertThrowsInstanceOf(() => arguments.callee, TypeError);

testDestructuring(1, {foo: 1, bar: 2}, 9);

function testStrict(a) {

    "use strict";

    a = 3;

    assertEq(arguments[0], 1);

    arguments[0] = 8;

    assertEq(a, 3);

    assertThrowsInstanceOf(() => arguments.callee, TypeError);

testStrict(1, 2);

function testMapped(a) {

    a = 3;

    assertEq(arguments[0], 3);

    arguments[0] = 5;

    assertEq(a, 5);

    assertEq(arguments.callee, testMapped);

testMapped(1);