v8/test/mjsunit/const-eval-init.js
verwaest@chromium.org aa7198dfdd This CL simplifies var / const by ensuring the behavior is consistent in itself, and with regular JS semantics; between regular var/const and eval-ed var/const.
Legacy const is changed so that a declaration declares a configurable, but non-writable, slot, and the initializer reconfigures it (when possible) to non-configurable non-writable. This avoids the need for "the hole" as marker value in JSContextExtensionObjects and GlobalObjects. Undefined is used instead.

BUG=
R=rossberg@chromium.org

Review URL: https://codereview.chromium.org/379893002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22379 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2014-07-14 14:01:04 +00:00

119 lines
3.9 KiB
JavaScript

// Copyright 2009 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: --allow-natives-syntax
// Test the handling of initialization of deleted const variables.
// This only makes sense in local scopes since the declaration and
// initialization of consts in the global scope happen at the same
// time.
function testIntroduceGlobal() {
var source =
// Deleting 'x' removes the local const property.
"delete x;" +
// Initialization redefines global 'x'.
"const x = 3; assertEquals(3, x);" +
// Test constness of the global 'x'.
"x = 4; assertEquals(3, x);";
eval(source);
}
testIntroduceGlobal();
assertEquals("undefined", typeof x);
function testAssignExistingGlobal() {
var source =
// Delete 'x' to remove the local const property.
"delete x;" +
// Initialization redefines global 'x'.
"const x = 5; assertEquals(5, x);" +
// Test constness of the global 'x'.
"x = 6; assertEquals(5, x);";
eval(source);
}
testAssignExistingGlobal();
assertEquals("undefined", typeof x);
function testAssignmentArgument(x) {
function local() {
var source = "delete x; const x = 7; assertEquals(7, x)";
eval(source);
}
local();
assertEquals("undefined", typeof x);
}
for (var i = 0; i < 5; i++) {
testAssignmentArgument();
}
%OptimizeFunctionOnNextCall(testAssignmentArgument);
testAssignmentArgument();
assertEquals("undefined", typeof x);
__defineSetter__('x', function() { throw 42; });
var finished = false;
function testRedefineGlobal() {
// Initialization redefines global 'x'.
var source = "delete x; const x = 8; finished = true;";
eval(source);
}
testRedefineGlobal();
assertTrue(finished);
function testInitFastCaseExtension() {
var source = "const x = 9; assertEquals(9, x); x = 10; assertEquals(9, x)";
eval(source);
}
testInitFastCaseExtension();
function testInitSlowCaseExtension() {
var source = "";
// Introduce 100 properties on the context extension object to force
// it in slow case.
for (var i = 0; i < 100; i++) source += ("var a" + i + " = " + i + ";");
source += "const x = 10; assertEquals(10, x); x = 11; assertEquals(10, x)";
eval(source);
}
testInitSlowCaseExtension();
function testAssignSurroundingContextSlot() {
var x = 12;
function local() {
var source = "delete x; const x = 13; assertEquals(13, x)";
eval(source);
}
local();
assertEquals(12, x);
}
testAssignSurroundingContextSlot();