Implement sloppy-mode block-defined functions (Annex B 3.3)

test/mjsunit/harmony/block-sloppy-function.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: --no-legacy-const --harmony-sloppy --harmony-sloppy-let
+// Flags: --harmony-sloppy-function --harmony-destructuring
+
+// Test Annex B 3.3 semantics for functions declared in blocks in sloppy mode.
+// http://www.ecma-international.org/ecma-262/6.0/#sec-block-level-function-declarations-web-legacy-compatibility-semantics
+
+(function overridingLocalFunction() {
+  var x = [];
+  assertEquals('function', typeof f);
+  function f() {
+    x.push(1);
+  }
+  f();
+  {
+    f();
+    function f() {
+      x.push(2);
+    }
+    f();
+  }
+  f();
+  {
+    f();
+    function f() {
+      x.push(3);
+    }
+    f();
+  }
+  f();
+  assertArrayEquals([1, 2, 2, 2, 3, 3, 3], x);
+})();
+
+(function newFunctionBinding() {
+  var x = [];
+  assertEquals('undefined', typeof f);
+  {
+    f();
+    function f() {
+      x.push(2);
+    }
+    f();
+  }
+  f();
+  {
+    f();
+    function f() {
+      x.push(3);
+    }
+    f();
+  }
+  f();
+  assertArrayEquals([2, 2, 2, 3, 3, 3], x);
+})();
+
+(function shadowingLetDoesntBind() {
+  let f = 1;
+  assertEquals(1, f);
+  {
+    let y = 3;
+    function f() {
+      y = 2;
+    }
+    f();
+    assertEquals(2, y);
+  }
+  assertEquals(1, f);
+})();
+
+(function shadowingClassDoesntBind() {
+  class f { }
+  assertEquals('class f { }', f.toString());
+  {
+    let y = 3;
+    function f() {
+      y = 2;
+    }
+    f();
+    assertEquals(2, y);
+  }
+  assertEquals('class f { }', f.toString());
+})();
+
+(function shadowingConstDoesntBind() {
+  const f = 1;
+  assertEquals(1, f);
+  {
+    let y = 3;
+    function f() {
+      y = 2;
+    }
+    f();
+    assertEquals(2, y);
+  }
+  assertEquals(1, f);
+})();
+
+(function shadowingVarBinds() {
+  var f = 1;
+  assertEquals(1, f);
+  {
+    let y = 3;
+    function f() {
+      y = 2;
+    }
+    f();
+    assertEquals(2, y);
+  }
+  assertEquals('function', typeof f);
+})();
+
+(function conditional() {
+  if (true) {
+    function f() { return 1; }
+  } else {
+    function f() { return 2; }
+  }
+  assertEquals(1, f());
+
+  if (false) {
+    function g() { return 1; }
+  } else {
+    function g() { return 2; }
+  }
+  assertEquals(2, g());
+})();
+
+(function skipExecution() {
+  {
+    function f() { return 1; }
+  }
+  assertEquals(1, f());
+  {
+    function f() { return 2; }
+  }
+  assertEquals(2, f());
+  L: {
+    assertEquals(3, f());
+    break L;
+    function f() { return 3; }
+  }
+  assertEquals(2, f());
+})();
+
+// Test that hoisting from blocks doesn't happen in global scope
+function globalUnhoisted() { return 0; }
+{
+  function globalUnhoisted() { return 1; }
+}
+assertEquals(0, globalUnhoisted());
+
+// Test that shadowing arguments is fine
+(function shadowArguments(x) {
+  assertArrayEquals([1], arguments);
+  {
+    assertEquals('function', typeof arguments);
+    function arguments() {}
+    assertEquals('function', typeof arguments);
+  }
+  assertEquals('function', typeof arguments);
+})(1);
+
+// Shadow function parameter
+(function shadowParameter(x) {
+  assertEquals(1, x);
+  {
+    function x() {}
+  }
+  assertEquals('function', typeof x);
+})(1);
+
+// Shadow function parameter
+(function shadowDefaultParameter(x = 0) {
+  assertEquals(1, x);
+  {
+    function x() {}
+  }
+  // TODO(littledan): Once destructured parameters are no longer
+  // let-bound, enable this assertion. This is the core of the test.
+  // assertEquals('function', typeof x);
+})(1);
+
+assertThrows(function notInDefaultScope(x = y) {
+  {
+    function y() {}
+  }
+  assertEquals('function', typeof y);
+  assertEquals(x, undefined);
+}, ReferenceError);