add-function-prototype.js

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function checkPrototype(fun, proto, resolvesPrototype) {

    var desc = Object.getOwnPropertyDescriptor(fun, "prototype");

    assertEq(desc.value, proto);

    assertEq(desc.configurable, !resolvesPrototype);

    assertEq(desc.enumerable, !resolvesPrototype);

    assertEq(desc.writable, true);

function addPrototype(fun, proto, resolvesPrototype) {

    fun.prototype = proto;

    checkPrototype(fun, proto, resolvesPrototype);

function test() {

    for (var i=0; i<50; i++) {

        addPrototype(function() {}, i, true);

        addPrototype(function*() {}, i, true);

        addPrototype(function async() {}, i, true);

        // Builtins, arrow functions, bound functions don't have a default

        // prototype property.

        addPrototype(Math.abs, i, false);

        addPrototype(Array.prototype.map, i, false);

        addPrototype(() => 1, i, false);

        addPrototype((function() {}).bind(null), i, false);

    // Now test this with a different IC for each function type.

    for (var i=0; i<50; i++) {

        var f = function() {};

        f.prototype = i;

        checkPrototype(f, i, true);

        f = function*() {};

        f.prototype = i;

        checkPrototype(f, i, true);

        f = function async() {};

        f.prototype = i;

        checkPrototype(f, i, true);

        Math.sin.prototype = i;

        checkPrototype(Math.sin, i, false);

        Array.prototype.filter.prototype = i;

        checkPrototype(Array.prototype.filter, i, false);

        f = () => 1;

        f.prototype = i;

        checkPrototype(f, i, false);

        f = (function() {}).bind(null);

        f.prototype = i;

        checkPrototype(f, i, false);

test();