[es6] Implement default parameters

test/mjsunit/harmony/default-parameters.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-default-parameters --harmony-arrow-functions
+// Flags: --harmony-rest-parameters
+
+
+(function TestDefaults() {
+  function f1(x = 1) { return x }
+  assertEquals(1, f1());
+  assertEquals(1, f1(undefined));
+  assertEquals(2, f1(2));
+  assertEquals(null, f1(null));
+
+  function f2(x, y = x) { return x + y; }
+  assertEquals(8, f2(4));
+  assertEquals(8, f2(4, undefined));
+  assertEquals(6, f2(4, 2));
+
+  function f3(x = 1, y) { return x + y; }
+  assertEquals(8, f3(5, 3));
+  assertEquals(3, f3(undefined, 2));
+  assertEquals(6, f3(4, 2));
+
+  function f4(x = () => 1) { return x() }
+  assertEquals(1, f4());
+  assertEquals(1, f4(undefined));
+  assertEquals(2, f4(() => 2));
+  assertThrows(() => f4(null), TypeError);
+
+  function f5(x, y = () => x) { return x + y(); }
+  assertEquals(8, f5(4));
+  assertEquals(8, f5(4, undefined));
+  assertEquals(6, f5(4, () => 2));
+
+  function f6(x = {a: 1, m() { return 2 }}) { return x.a + x.m(); }
+  assertEquals(3, f6());
+  assertEquals(3, f6(undefined));
+  assertEquals(5, f6({a: 2, m() { return 3 }}));
+
+  var g1 = (x = 1) => { return x };
+  assertEquals(1, g1());
+  assertEquals(1, g1(undefined));
+  assertEquals(2, g1(2));
+  assertEquals(null, g1(null));
+
+  var g2 = (x, y = x) => { return x + y; };
+  assertEquals(8, g2(4));
+  assertEquals(8, g2(4, undefined));
+  assertEquals(6, g2(4, 2));
+
+  var g3 = (x = 1, y) => { return x + y; };
+  assertEquals(8, g3(5, 3));
+  assertEquals(3, g3(undefined, 2));
+  assertEquals(6, g3(4, 2));
+
+  var g4 = (x = () => 1) => { return x() };
+  assertEquals(1, g4());
+  assertEquals(1, g4(undefined));
+  assertEquals(2, g4(() => 2));
+  assertThrows(() => g4(null), TypeError);
+
+  var g5 = (x, y = () => x) => { return x + y(); };
+  assertEquals(8, g5(4));
+  assertEquals(8, g5(4, undefined));
+  assertEquals(6, g5(4, () => 2));
+
+  var g6 = (x = {a: 1, m() { return 2 }}) => { return x.a + x.m(); };
+  assertEquals(3, g6());
+  assertEquals(3, g6(undefined));
+  assertEquals(5, g6({a: 2, m() { return 3 }}));
+}());
+
+
+(function TestEvalInParameters() {
+  function f1(x = eval(0)) { return x }
+  assertEquals(0, f1());
+  function f2(x = () => eval(1)) { return x() }
+  assertEquals(1, f2());
+})();
+
+
+(function TestParameterScoping() {

[adamk, 2015/08/12 18:22:59]

This test looks like it could use some cases with more complex evals, e.g.,
those that declare variables with "var" and "let" (in both strict and sloppy
modes).

[rossberg, 2015/08/13 11:06:36]

Since these don't actually work correctly yet I just added a TODO.

+  var x = 1;
+
+  function f1(a = x) { var x = 2; return a; }
+  assertEquals(1, f1());
+  function f2(a = x) { function x() {}; return a; }
+  assertEquals(1, f2());
+  function f3(a = x) { 'use strict'; let x = 2; return a; }
+  assertEquals(1, f3());
+  function f4(a = x) { 'use strict'; const x = 2; return a; }
+  assertEquals(1, f4());
+  function f5(a = x) { 'use strict'; function x() {}; return a; }
+  assertEquals(1, f5());
+  function f6(a = eval("x")) { var x; return a; }
+  assertEquals(1, f6());
+  function f61(a = eval("x")) { 'use strict'; var x; return a; }
+  assertEquals(1, f61());
+  function f62(a = eval("'use strict'; x")) { var x; return a; }
+  assertEquals(1, f62());
+  function f7(a = function() { return x }) { var x; return a(); }
+  assertEquals(1, f7());
+  function f8(a = () => x) { var x; return a(); }
+  assertEquals(1, f8());
+  function f9(a = () => eval("x")) { var x; return a(); }
+  assertEquals(1, f9());
+  function f91(a = () => eval("x")) { 'use strict'; var x; return a(); }
+  assertEquals(1, f91());
+  function f92(a = () => { 'use strict'; return eval("x") }) { var x; return a(); }
+  assertEquals(1, f92());
+  function f93(a = () => eval("'use strict'; x")) { var x; return a(); }
+  assertEquals(1, f93());
+
+  var g1 = (a = x) => { var x = 2; return a; };
+  assertEquals(1, g1());
+  var g2 = (a = x) => { function x() {}; return a; };
+  assertEquals(1, g2());
+  var g3 = (a = x) => { 'use strict'; let x = 2; return a; };
+  assertEquals(1, g3());
+  var g4 = (a = x) => { 'use strict'; const x = 2; return a; };
+  assertEquals(1, g4());
+  var g5 = (a = x) => { 'use strict'; function x() {}; return a; };
+  assertEquals(1, g5());
+  var g6 = (a = eval("x")) => { var x; return a; };
+  assertEquals(1, g6());
+  var g61 = (a = eval("x")) => { 'use strict'; var x; return a; };
+  assertEquals(1, g61());
+  var g62 = (a = eval("'use strict'; x")) => { var x; return a; };
+  assertEquals(1, g62());
+  var g7 = (a = function() { return x }) => { var x; return a(); };
+  assertEquals(1, g7());
+  var g8 = (a = () => x) => { var x; return a(); };
+  assertEquals(1, g8());
+  var g9 = (a = () => eval("x")) => { var x; return a(); };
+  assertEquals(1, g9());
+  var g91 = (a = () => eval("x")) => { 'use strict'; var x; return a(); };
+  assertEquals(1, g91());
+  var g92 = (a = () => { 'use strict'; return eval("x") }) => { var x; return a(); };
+  assertEquals(1, g92());
+  var g93 = (a = () => eval("'use strict'; x")) => { var x; return a(); };
+  assertEquals(1, g93());
+
+  var f11 = function f(x = f) { var f; return x; }
+  assertSame(f11, f11());
+  var f12 = function f(x = f) { function f() {}; return x; }
+  assertSame(f12, f12());
+  var f13 = function f(x = f) { 'use strict'; let f; return x; }
+  assertSame(f13, f13());
+  var f14 = function f(x = f) { 'use strict'; const f = 0; return x; }
+  assertSame(f14, f14());
+  var f15 = function f(x = f) { 'use strict'; function f() {}; return x; }
+  assertSame(f15, f15());
+  var f16 = function f(f = 7, x = f) { return x; }
+  assertSame(7, f16());
+
+  var o1 = {f: function(x = this) { return x; }};
+  assertSame(o1, o1.f());
+  assertSame(1, o1.f(1));
+})();
+
+
+(function TestParameterTDZ() {
+  function f1(a = x, x) { return a }
+  assertThrows(() => f1(undefined, 4), ReferenceError);
+  assertEquals(4, f1(4, 5));
+  function f2(a = eval("x"), x) { return a }
+  assertThrows(() => f2(undefined, 4), ReferenceError);
+  assertEquals(4, f2(4, 5));
+  function f3(a = eval("x"), x) { 'use strict'; return a }
+  assertThrows(() => f3(undefined, 4), ReferenceError);
+  assertEquals(4, f3(4, 5));
+  function f4(a = eval("'use strict'; x"), x) { return a }
+  assertThrows(() => f4(undefined, 4), ReferenceError);
+  assertEquals(4, f4(4, 5));
+
+  function f5(a = () => x, x) { return a() }
+  assertEquals(4, f5(() => 4, 5));
+  function f6(a = () => eval("x"), x) { return a() }
+  assertEquals(4, f6(() => 4, 5));
+  function f7(a = () => eval("x"), x) { 'use strict'; return a() }
+  assertEquals(4, f7(() => 4, 5));
+  function f8(a = () => eval("'use strict'; x"), x) { return a() }
+  assertEquals(4, f8(() => 4, 5));
+
+  function f11(a = x, x = 2) { return a }
+  assertThrows(() => f11(), ReferenceError);
+  assertThrows(() => f11(undefined), ReferenceError);
+  assertThrows(() => f11(undefined, 4), ReferenceError);
+  assertEquals(4, f1(4, 5));
+  function f12(a = eval("x"), x = 2) { return a }
+  assertThrows(() => f12(), ReferenceError);
+  assertThrows(() => f12(undefined), ReferenceError);
+  assertThrows(() => f12(undefined, 4), ReferenceError);
+  assertEquals(4, f12(4, 5));
+  function f13(a = eval("x"), x = 2) { 'use strict'; return a }
+  assertThrows(() => f13(), ReferenceError);
+  assertThrows(() => f13(undefined), ReferenceError);
+  assertThrows(() => f13(undefined, 4), ReferenceError);
+  assertEquals(4, f13(4, 5));
+  function f14(a = eval("'use strict'; x"), x = 2) { return a }
+  assertThrows(() => f14(), ReferenceError);
+  assertThrows(() => f14(undefined), ReferenceError);
+  assertThrows(() => f14(undefined, 4), ReferenceError);
+  assertEquals(4, f14(4, 5));
+
+  function f34(x = function() { return a }, ...a) { return x()[0] }
+  assertEquals(4, f34(undefined, 4));
+  function f35(x = () => a, ...a) { return x()[0] }
+  assertEquals(4, f35(undefined, 4));
+  function f36(x = () => eval("a"), ...a) { return x()[0] }
+  assertEquals(4, f36(undefined, 4));
+  function f37(x = () => eval("a"), ...a) { 'use strict'; return x()[0] }
+  assertEquals(4, f37(undefined, 4));
+  function f38(x = () => { 'use strict'; return eval("a") }, ...a) { return x()[0] }
+  assertEquals(4, f38(undefined, 4));
+  function f39(x = () => eval("'use strict'; a"), ...a) { return x()[0] }
+  assertEquals(4, f39(undefined, 4));
+
+  var g34 = (x = function() { return a }, ...a) => { return x()[0] };
+  assertEquals(4, g34(undefined, 4));
+  var g35 = (x = () => a, ...a) => { return x()[0] };
+  assertEquals(4, g35(undefined, 4));
+})();
+
+
+(function TestArgumentsForNonSimpleParameters() {
+  function f1(x = 900) { arguments[0] = 1; return x }
+  assertEquals(9, f1(9));
+  assertEquals(900, f1());
+  function f2(x = 1001) { x = 2; return arguments[0] }
+  assertEquals(10, f2(10));
+  assertEquals(undefined, f2());
+}());
+
+
+(function TestFunctionLength() {
+  // TODO(rossberg): Fix arity.
+  // assertEquals(0, (function(x = 1) {}).length);
+  // assertEquals(0, (function(x = 1, ...a) {}).length);
+  // assertEquals(1, (function(x, y = 1) {}).length);
+  // assertEquals(1, (function(x, y = 1, ...a) {}).length);
+  // assertEquals(2, (function(x, y, z = 1) {}).length);
+  // assertEquals(2, (function(x, y, z = 1, ...a) {}).length);
+  // assertEquals(1, (function(x, y = 1, z) {}).length);
+  // assertEquals(1, (function(x, y = 1, z, ...a) {}).length);
+  // assertEquals(1, (function(x, y = 1, z, v = 2) {}).length);
+  // assertEquals(1, (function(x, y = 1, z, v = 2, ...a) {}).length);
+})();