Let bound iteration variables in for-loops

test/mjsunit/harmony/block-for.js

+// Copyright 2011 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --harmony-scoping
+
+function props(x) {
+  var array = [];
+  for (let p in x) array.push(p);
+  return array.sort();
+}
+
+assertEquals(0, props({}).length, "olen0");

[Lasse Reichstein, 2011/10/17 11:49:40]

You can safely choose to omit the third parameter of the test without loss since
our test framework reports the line now.

[Steven, 2011/10/17 12:18:29]

Done.

+assertEquals(1, props({x:1}).length, "olen1");
+assertEquals(2, props({x:1, y:2}).length, "olen2");
+
+assertArrayEquals(["x"], props({x:1}), "x");
+assertArrayEquals(["x", "y"], props({x:1, y:2}), "xy");
+assertArrayEquals(["x", "y", "zoom"], props({x:1, y:2, zoom:3}), "xyzoom");
+
+assertEquals(0, props([]).length, "alen0");
+assertEquals(1, props([1]).length, "alen1");
+assertEquals(2, props([1,2]).length, "alen2");
+
+assertArrayEquals(["0"], props([1]), "0");
+assertArrayEquals(["0", "1"], props([1,2]), "01");
+assertArrayEquals(["0", "1", "2"], props([1,2,3]), "012");
+
+var o = {};
+var a = [];
+for (let i = 0x0020; i < 0x01ff; i+=2) {

[Lasse Reichstein, 2011/10/17 11:49:40]

Try declaring i and s prior to this loop, and see that their values haven't
changed afterwards.

[Steven, 2011/10/17 12:18:29]

Done.

+  let s = 'char:' + String.fromCharCode(i);
+  a.push(s);
+  o[s] = i;
+}
+assertArrayEquals(a, props(o), "charcodes");
+
+var a = [];
+assertEquals(0, props(a).length, "proplen0");
+a[Math.pow(2,30)-1] = 0;
+assertEquals(1, props(a).length, "proplen1");
+a[Math.pow(2,31)-1] = 0;
+assertEquals(2, props(a).length, "proplen2");
+a[1] = 0;
+assertEquals(3, props(a).length, "proplen3");
+
+var result = '';
+for (let p in {a : [0], b : 1}) { result += p; }
+assertEquals('ab', result, "ab");
+
+var result = '';
+for (let p in {a : {v:1}, b : 1}) { result += p; }
+assertEquals('ab', result, "ab-nodeep");
+
+var result = '';
+for (let p in { get a() {}, b : 1}) { result += p; }
+assertEquals('ab', result, "abget");
+
+var result = '';
+for (let p in { get a() {}, set a(x) {}, b : 1}) { result += p; }
+assertEquals('ab', result, "abgetset");
+
+
+// Check that there is exactly one variable without initializer
+// in a for-in statement with let variables.
+assertThrows("function foo() { for (let in {}) { } }", SyntaxError);
+assertThrows("function foo() { for (let x = 3 in {}) { } }", SyntaxError);
+assertThrows("function foo() { for (let x, y in {}) { } }", SyntaxError);
+assertThrows("function foo() { for (let x = 3, y in {}) { } }", SyntaxError);
+assertThrows("function foo() { for (let x, y = 4 in {}) { } }", SyntaxError);
+assertThrows("function foo() { for (let x = 3, y = 4 in {}) { } }", SyntaxError);
+
+
+// In a normal for statement the iteration variable is not
+// freshly allocated for each iteration.
+function closures1() {
+  let a = [];
+  for (let i = 0; i < 5; ++i) {
+    a.push(function () { return i; });
+  }
+  for (let j = 0; j < 5; ++j) {
+    assertEquals(5, a[j]());
+  }
+}
+closures1();
+
+
+function closures2() {
+  let a = [], b = [];
+  for (let i = 0, j = 10; i < 5; ++i, ++j) {
+    a.push(function () { return i; });
+    b.push(function () { return j; });
+  }
+  for (let k = 0; k < 5; ++k) {
+    assertEquals(5, a[k]());
+    assertEquals(15, b[k]());
+  }
+}
+closures2();
+
+
+// In a for-in statement the iteration variable is fresh
+// for earch iteration.
+function closures3(x) {
+  let a = [];
+  for (let p in x) {
+    a.push(function () { return p; });
+  }
+  let k = 0;
+  for (let q in x) {
+    assertEquals(q, a[k]());
+    ++k;
+  }
+}
+closures3({a : [0], b : 1, c : {v : 1}, get d() {}, set e(x) {}});