v8/test/mjsunit/strict-mode.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
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

function CheckStrictMode(code, exception) {
  assertDoesNotThrow(code);
  assertThrows("'use strict';\n" + code, exception);
  assertThrows('"use strict";\n' + code, exception);
  assertDoesNotThrow("\
    function outer() {\
      function inner() {\n"
        + code +
      "\n}\
    }");
  assertThrows("\
    function outer() {\
      'use strict';\
      function inner() {\n"
        + code +
      "\n}\
    }", exception);
}

function CheckFunctionConstructorStrictMode() {
  var args = [];
  for (var i = 0; i < arguments.length; i ++) {
    args[i] = arguments[i];
  }
  // Create non-strict function. No exception.
  args[arguments.length] = "";
  assertDoesNotThrow(function() {
    Function.apply(this, args);
  });
  // Create strict mode function. Exception expected.
  args[arguments.length] = "'use strict';";
  assertThrows(function() {
    Function.apply(this, args);
  }, SyntaxError);
}

// Incorrect 'use strict' directive.
(function UseStrictEscape() {
  "use\\x20strict";
  with ({}) {};
})();

// 'use strict' in non-directive position.
(function UseStrictNonDirective() {
  void(0);
  "use strict";
  with ({}) {};
})();

// Multiple directives, including "use strict".
assertThrows('\
"directive 1";\
"another directive";\
"use strict";\
"directive after strict";\
"and one more";\
with({}) {}', SyntaxError);

// 'with' disallowed in strict mode.
CheckStrictMode("with({}) {}", SyntaxError);

// Function named 'eval'.
CheckStrictMode("function eval() {}", SyntaxError);

// Function named 'arguments'.
CheckStrictMode("function arguments() {}", SyntaxError);

// Function parameter named 'eval'.
CheckStrictMode("function foo(a, b, eval, c, d) {}", SyntaxError);

// Function parameter named 'arguments'.
CheckStrictMode("function foo(a, b, arguments, c, d) {}", SyntaxError);

// Property accessor parameter named 'eval'.
CheckStrictMode("var o = { set foo(eval) {} }", SyntaxError);

// Property accessor parameter named 'arguments'.
CheckStrictMode("var o = { set foo(arguments) {} }", SyntaxError);

// Duplicate function parameter name.
CheckStrictMode("function foo(a, b, c, d, b) {}", SyntaxError);

// Function constructor: eval parameter name.
CheckFunctionConstructorStrictMode("eval");

// Function constructor: arguments parameter name.
CheckFunctionConstructorStrictMode("arguments");

// Function constructor: duplicate parameter name.
CheckFunctionConstructorStrictMode("a", "b", "c", "b");
CheckFunctionConstructorStrictMode("a,b,c,b");

// catch(eval)
CheckStrictMode("try{}catch(eval){};", SyntaxError);

// catch(arguments)
CheckStrictMode("try{}catch(arguments){};", SyntaxError);

// var eval
CheckStrictMode("var eval;", SyntaxError);

// var arguments
CheckStrictMode("var arguments;", SyntaxError);

// Strict mode applies to the function in which the directive is used..
assertThrows('\
function foo(eval) {\
  "use strict";\
}', SyntaxError);

// Strict mode doesn't affect the outer stop of strict code.
(function NotStrict(eval) {
  function Strict() {
    "use strict";
  }
  with ({}) {};
})();

// Octal literal
CheckStrictMode("var x = 012");
CheckStrictMode("012");
CheckStrictMode("'Hello octal\\032'");
CheckStrictMode("function octal() { return 012; }");
CheckStrictMode("function octal() { return '\\032'; }");

(function ValidEscape() {
  "use strict";
  var x = '\0';
  var y = "\0";
})();

// Octal before "use strict"
assertThrows('\
  function strict() {\
    "octal\\032directive";\
    "use strict";\
  }', SyntaxError);

// Duplicate data properties.
CheckStrictMode("var x = { dupe : 1, nondupe: 3, dupe : 2 };", SyntaxError);
CheckStrictMode("var x = { '1234' : 1, '2345' : 2, '1234' : 3 };", SyntaxError);
CheckStrictMode("var x = { '1234' : 1, '2345' : 2, 1234 : 3 };", SyntaxError);
CheckStrictMode("var x = { 3.14 : 1, 2.71 : 2, 3.14 : 3 };", SyntaxError);
CheckStrictMode("var x = { 3.14 : 1, '3.14' : 2 };", SyntaxError);
CheckStrictMode("var x = { \
  123: 1, \
  123.00000000000000000000000000000000000000000000000000000000000000000001: 2 \
}", SyntaxError);

// Non-conflicting data properties.
(function StrictModeNonDuplicate() {
  "use strict";
  var x = { 123 : 1, "0123" : 2 };
  var x = {
    123: 1,
    '123.00000000000000000000000000000000000000000000000000000000000000000001':
      2
  };
})();

// Two getters (non-strict)
assertThrows("var x = { get foo() { }, get foo() { } };", SyntaxError);
assertThrows("var x = { get foo(){}, get 'foo'(){}};", SyntaxError);
assertThrows("var x = { get 12(){}, get '12'(){}};", SyntaxError);

// Two setters (non-strict)
assertThrows("var x = { set foo(v) { }, set foo(v) { } };", SyntaxError);
assertThrows("var x = { set foo(v) { }, set 'foo'(v) { } };", SyntaxError);
assertThrows("var x = { set 13(v) { }, set '13'(v) { } };", SyntaxError);

// Setter and data (non-strict)
assertThrows("var x = { foo: 'data', set foo(v) { } };", SyntaxError);
assertThrows("var x = { set foo(v) { }, foo: 'data' };", SyntaxError);
assertThrows("var x = { foo: 'data', set 'foo'(v) { } };", SyntaxError);
assertThrows("var x = { set foo(v) { }, 'foo': 'data' };", SyntaxError);
assertThrows("var x = { 'foo': 'data', set foo(v) { } };", SyntaxError);
assertThrows("var x = { set 'foo'(v) { }, foo: 'data' };", SyntaxError);
assertThrows("var x = { 'foo': 'data', set 'foo'(v) { } };", SyntaxError);
assertThrows("var x = { set 'foo'(v) { }, 'foo': 'data' };", SyntaxError);
assertThrows("var x = { 12: 1, set '12'(v){}};", SyntaxError);
assertThrows("var x = { 12: 1, set 12(v){}};", SyntaxError);
assertThrows("var x = { '12': 1, set '12'(v){}};", SyntaxError);
assertThrows("var x = { '12': 1, set 12(v){}};", SyntaxError);

// Getter and data (non-strict)
assertThrows("var x = { foo: 'data', get foo() { } };", SyntaxError);
assertThrows("var x = { get foo() { }, foo: 'data' };", SyntaxError);
assertThrows("var x = { 'foo': 'data', get foo() { } };", SyntaxError);
assertThrows("var x = { get 'foo'() { }, 'foo': 'data' };", SyntaxError);
assertThrows("var x = { '12': 1, get '12'(){}};", SyntaxError);
assertThrows("var x = { '12': 1, get 12(){}};", SyntaxError);

// Assignment to eval or arguments
CheckStrictMode("function strict() { eval = undefined; }", SyntaxError);
CheckStrictMode("function strict() { arguments = undefined; }", SyntaxError);
CheckStrictMode("function strict() { print(eval = undefined); }", SyntaxError);
CheckStrictMode("function strict() { print(arguments = undefined); }",
                SyntaxError);
CheckStrictMode("function strict() { var x = eval = undefined; }", SyntaxError);
CheckStrictMode("function strict() { var x = arguments = undefined; }",
                SyntaxError);

// Compound assignment to eval or arguments
CheckStrictMode("function strict() { eval *= undefined; }", SyntaxError);
CheckStrictMode("function strict() { arguments /= undefined; }", SyntaxError);
CheckStrictMode("function strict() { print(eval %= undefined); }", SyntaxError);
CheckStrictMode("function strict() { print(arguments %= undefined); }",
                SyntaxError);
CheckStrictMode("function strict() { var x = eval += undefined; }",
                SyntaxError);
CheckStrictMode("function strict() { var x = arguments -= undefined; }",
                SyntaxError);
CheckStrictMode("function strict() { eval <<= undefined; }", SyntaxError);
CheckStrictMode("function strict() { arguments >>= undefined; }", SyntaxError);
CheckStrictMode("function strict() { print(eval >>>= undefined); }",
                SyntaxError);
CheckStrictMode("function strict() { print(arguments &= undefined); }",
                SyntaxError);
CheckStrictMode("function strict() { var x = eval ^= undefined; }",
                SyntaxError);
CheckStrictMode("function strict() { var x = arguments |= undefined; }",
                SyntaxError);

// Postfix increment with eval or arguments
CheckStrictMode("function strict() { eval++; }", SyntaxError);
CheckStrictMode("function strict() { arguments++; }", SyntaxError);
CheckStrictMode("function strict() { print(eval++); }", SyntaxError);
CheckStrictMode("function strict() { print(arguments++); }", SyntaxError);
CheckStrictMode("function strict() { var x = eval++; }", SyntaxError);
CheckStrictMode("function strict() { var x = arguments++; }", SyntaxError);

// Postfix decrement with eval or arguments
CheckStrictMode("function strict() { eval--; }", SyntaxError);
CheckStrictMode("function strict() { arguments--; }", SyntaxError);
CheckStrictMode("function strict() { print(eval--); }", SyntaxError);
CheckStrictMode("function strict() { print(arguments--); }", SyntaxError);
CheckStrictMode("function strict() { var x = eval--; }", SyntaxError);
CheckStrictMode("function strict() { var x = arguments--; }", SyntaxError);

// Prefix increment with eval or arguments
CheckStrictMode("function strict() { ++eval; }", SyntaxError);
CheckStrictMode("function strict() { ++arguments; }", SyntaxError);
CheckStrictMode("function strict() { print(++eval); }", SyntaxError);
CheckStrictMode("function strict() { print(++arguments); }", SyntaxError);
CheckStrictMode("function strict() { var x = ++eval; }", SyntaxError);
CheckStrictMode("function strict() { var x = ++arguments; }", SyntaxError);

// Prefix decrement with eval or arguments
CheckStrictMode("function strict() { --eval; }", SyntaxError);
CheckStrictMode("function strict() { --arguments; }", SyntaxError);
CheckStrictMode("function strict() { print(--eval); }", SyntaxError);
CheckStrictMode("function strict() { print(--arguments); }", SyntaxError);
CheckStrictMode("function strict() { var x = --eval; }", SyntaxError);
CheckStrictMode("function strict() { var x = --arguments; }", SyntaxError);

// Use of const in strict mode is disallowed in anticipation of ES Harmony.
CheckStrictMode("const x = 0;", SyntaxError);
CheckStrictMode("for (const x = 0; false;) {}", SyntaxError);
CheckStrictMode("function strict() { const x = 0; }", SyntaxError);

// Strict mode only allows functions in SourceElements
CheckStrictMode("if (true) { function invalid() {} }", SyntaxError);
CheckStrictMode("for (;false;) { function invalid() {} }", SyntaxError);
CheckStrictMode("{ function invalid() {} }", SyntaxError);
CheckStrictMode("try { function invalid() {} } catch(e) {}", SyntaxError);
CheckStrictMode("try { } catch(e) { function invalid() {} }", SyntaxError);
CheckStrictMode("function outer() {{ function invalid() {} }}", SyntaxError);

// Delete of an unqualified identifier
CheckStrictMode("delete unqualified;", SyntaxError);
CheckStrictMode("function strict() { delete unqualified; }", SyntaxError);
CheckStrictMode("function function_name() { delete function_name; }",
                SyntaxError);
CheckStrictMode("function strict(parameter) { delete parameter; }",
                SyntaxError);
CheckStrictMode("function strict() { var variable; delete variable; }",
                SyntaxError);
CheckStrictMode("var variable; delete variable;", SyntaxError);

(function TestStrictDelete() {
  "use strict";
  // "delete this" is allowed in strict mode and should work.
  function strict_delete() { delete this; }
  strict_delete();
})();

// Prefix unary operators other than delete, ++, -- are valid in strict mode
(function StrictModeUnaryOperators() {
  "use strict";
  var x = [void eval, typeof eval, +eval, -eval, ~eval, !eval];
  var y = [void arguments, typeof arguments,
           +arguments, -arguments, ~arguments, !arguments];
})();

// 7.6.1.2 Future Reserved Words
var future_reserved_words = [
  "class",
  "enum",
  "export",
  "extends",
  "import",
  "super",
  "implements",
  "interface",
  "let",
  "package",
  "private",
  "protected",
  "public",
  "static",
  "yield" ];

function testFutureReservedWord(word) {
  // Simple use of each reserved word
  CheckStrictMode("var " + word + " = 1;", SyntaxError);

  // object literal properties
  eval("var x = { " + word + " : 42 };");
  eval("var x = { get " + word + " () {} };");
  eval("var x = { set " + word + " (value) {} };");

  // object literal with string literal property names
  eval("var x = { '" + word + "' : 42 };");
  eval("var x = { get '" + word + "' () { } };");
  eval("var x = { set '" + word + "' (value) { } };");
  eval("var x = { get '" + word + "' () { 'use strict'; } };");
  eval("var x = { set '" + word + "' (value) { 'use strict'; } };");

  // Function names and arguments, strict and non-strict contexts
  CheckStrictMode("function " + word + " () {}", SyntaxError);
  CheckStrictMode("function foo (" + word + ") {}", SyntaxError);
  CheckStrictMode("function foo (" + word + ", " + word + ") {}", SyntaxError);
  CheckStrictMode("function foo (a, " + word + ") {}", SyntaxError);
  CheckStrictMode("function foo (" + word + ", a) {}", SyntaxError);
  CheckStrictMode("function foo (a, " + word + ", b) {}", SyntaxError);
  CheckStrictMode("var foo = function (" + word + ") {}", SyntaxError);

  // Function names and arguments when the body is strict
  assertThrows("function " + word + " () { 'use strict'; }", SyntaxError);
  assertThrows("function foo (" + word + ")  'use strict'; {}", SyntaxError);
  assertThrows("function foo (" + word + ", " + word + ") { 'use strict'; }",
               SyntaxError);
  assertThrows("function foo (a, " + word + ") { 'use strict'; }", SyntaxError);
  assertThrows("function foo (" + word + ", a) { 'use strict'; }", SyntaxError);
  assertThrows("function foo (a, " + word + ", b) { 'use strict'; }",
               SyntaxError);
  assertThrows("var foo = function (" + word + ") { 'use strict'; }",
               SyntaxError);

  // get/set when the body is strict
  eval("var x = { get " + word + " () { 'use strict'; } };");
  eval("var x = { set " + word + " (value) { 'use strict'; } };");
  assertThrows("var x = { get foo(" + word + ") { 'use strict'; } };",
               SyntaxError);
  assertThrows("var x = { set foo(" + word + ") { 'use strict'; } };",
               SyntaxError);
}

for (var i = 0; i < future_reserved_words.length; i++) {
  testFutureReservedWord(future_reserved_words[i]);
}

function testAssignToUndefined(test, should_throw) {
  try {
    test();
  } catch (e) {
    assertTrue(should_throw, "strict mode");
    assertInstanceof(e, ReferenceError, "strict mode");
    return;
  }
  assertFalse(should_throw, "strict mode");
}

function repeat(n, f) {
  for (var i = 0; i < n; i ++) { f(); }
}

function assignToUndefined() {
  "use strict";
  possibly_undefined_variable_for_strict_mode_test = "should throw?";
}

testAssignToUndefined(assignToUndefined, true);
testAssignToUndefined(assignToUndefined, true);
testAssignToUndefined(assignToUndefined, true);

possibly_undefined_variable_for_strict_mode_test = "value";

testAssignToUndefined(assignToUndefined, false);
testAssignToUndefined(assignToUndefined, false);
testAssignToUndefined(assignToUndefined, false);

delete possibly_undefined_variable_for_strict_mode_test;

testAssignToUndefined(assignToUndefined, true);
testAssignToUndefined(assignToUndefined, true);
testAssignToUndefined(assignToUndefined, true);

repeat(10, function() { testAssignToUndefined(assignToUndefined, true); });
possibly_undefined_variable_for_strict_mode_test = "value";
repeat(10, function() { testAssignToUndefined(assignToUndefined, false); });
delete possibly_undefined_variable_for_strict_mode_test;
repeat(10, function() { testAssignToUndefined(assignToUndefined, true); });
possibly_undefined_variable_for_strict_mode_test = undefined;
repeat(10, function() { testAssignToUndefined(assignToUndefined, false); });

function assignToUndefinedWithEval() {
  "use strict";
  possibly_undefined_variable_for_strict_mode_test_with_eval = "should throw?";
  eval("");
}

testAssignToUndefined(assignToUndefinedWithEval, true);
testAssignToUndefined(assignToUndefinedWithEval, true);
testAssignToUndefined(assignToUndefinedWithEval, true);

possibly_undefined_variable_for_strict_mode_test_with_eval = "value";

testAssignToUndefined(assignToUndefinedWithEval, false);
testAssignToUndefined(assignToUndefinedWithEval, false);
testAssignToUndefined(assignToUndefinedWithEval, false);

delete possibly_undefined_variable_for_strict_mode_test_with_eval;

testAssignToUndefined(assignToUndefinedWithEval, true);
testAssignToUndefined(assignToUndefinedWithEval, true);
testAssignToUndefined(assignToUndefinedWithEval, true);

repeat(10, function() {
             testAssignToUndefined(assignToUndefinedWithEval, true);
           });
possibly_undefined_variable_for_strict_mode_test_with_eval = "value";
repeat(10, function() {
             testAssignToUndefined(assignToUndefinedWithEval, false);
           });
delete possibly_undefined_variable_for_strict_mode_test_with_eval;
repeat(10, function() {
             testAssignToUndefined(assignToUndefinedWithEval, true);
           });
possibly_undefined_variable_for_strict_mode_test_with_eval = undefined;
repeat(10, function() {
             testAssignToUndefined(assignToUndefinedWithEval, false);
           });



(function testDeleteNonConfigurable() {
  function delete_property(o) {
    "use strict";
    delete o.property;
  }
  function delete_element(o, i) {
    "use strict";
    delete o[i];
  }

  var object = {};

  Object.defineProperty(object, "property", { value: "property_value" });
  Object.defineProperty(object, "1", { value: "one" });
  Object.defineProperty(object, 7, { value: "seven" });
  Object.defineProperty(object, 3.14, { value: "pi" });

  assertThrows(function() { delete_property(object); }, TypeError);
  assertEquals(object.property, "property_value");
  assertThrows(function() { delete_element(object, "1"); }, TypeError);
  assertThrows(function() { delete_element(object, 1); }, TypeError);
  assertEquals(object[1], "one");
  assertThrows(function() { delete_element(object, "7"); }, TypeError);
  assertThrows(function() { delete_element(object, 7); }, TypeError);
  assertEquals(object[7], "seven");
  assertThrows(function() { delete_element(object, "3.14"); }, TypeError);
  assertThrows(function() { delete_element(object, 3.14); }, TypeError);
  assertEquals(object[3.14], "pi");
})();

// Not transforming this in Function.call and Function.apply.
(function testThisTransformCallApply() {
  function non_strict() {
    return this;
  }
  function strict() {
    "use strict";
    return this;
  }

  var global_object = (function() { return this; })();
  var object = {};

  // Non-strict call.
  assertTrue(non_strict.call(null) === global_object);
  assertTrue(non_strict.call(undefined) === global_object);
  assertEquals(typeof non_strict.call(7), "object");
  assertEquals(typeof non_strict.call("Hello"), "object");
  assertTrue(non_strict.call(object) === object);

  // Non-strict apply.
  assertTrue(non_strict.apply(null) === global_object);
  assertTrue(non_strict.apply(undefined) === global_object);
  assertEquals(typeof non_strict.apply(7), "object");
  assertEquals(typeof non_strict.apply("Hello"), "object");
  assertTrue(non_strict.apply(object) === object);

  // Strict call.
  assertTrue(strict.call(null) === null);
  assertTrue(strict.call(undefined) === undefined);
  assertEquals(typeof strict.call(7), "number");
  assertEquals(typeof strict.call("Hello"), "string");
  assertTrue(strict.call(object) === object);

  // Strict apply.
  assertTrue(strict.apply(null) === null);
  assertTrue(strict.apply(undefined) === undefined);
  assertEquals(typeof strict.apply(7), "number");
  assertEquals(typeof strict.apply("Hello"), "string");
  assertTrue(strict.apply(object) === object);
})();

(function testThisTransform() {
  try {
    function strict() {
      "use strict";
      return typeof(this);
    }
    function nonstrict() {
      return typeof(this);
    }

    // Concat to avoid symbol.
    var strict_name = "str" + "ict";
    var nonstrict_name = "non" + "str" + "ict";
    var strict_number = 17;
    var nonstrict_number = 19;
    var strict_name_get = "str" + "ict" + "get";
    var nonstrict_name_get = "non" + "str" + "ict" + "get"
    var strict_number_get = 23;
    var nonstrict_number_get = 29;

    function install(t) {
      t.prototype.strict = strict;
      t.prototype.nonstrict = nonstrict;
      t.prototype[strict_number] = strict;
      t.prototype[nonstrict_number] = nonstrict;
      Object.defineProperty(t.prototype, strict_name_get,
                            { get: function() { return strict; },
                              configurable: true });
      Object.defineProperty(t.prototype, nonstrict_name_get,
                            { get: function() { return nonstrict; },
                              configurable: true });
      Object.defineProperty(t.prototype, strict_number_get,
                            { get: function() { return strict; },
                              configurable: true });
      Object.defineProperty(t.prototype, nonstrict_number_get,
                            { get: function() { return nonstrict; },
                              configurable: true });
    }

    function cleanup(t) {
      delete t.prototype.strict;
      delete t.prototype.nonstrict;
      delete t.prototype[strict_number];
      delete t.prototype[nonstrict_number];
      delete t.prototype[strict_name_get];
      delete t.prototype[nonstrict_name_get];
      delete t.prototype[strict_number_get];
      delete t.prototype[nonstrict_number_get];
    }

    // Set up fakes
    install(String);
    install(Number);
    install(Boolean)

    function callStrict(o) {
      return o.strict();
    }
    function callNonStrict(o) {
      return o.nonstrict();
    }
    function callKeyedStrict(o) {
      return o[strict_name]();
    }
    function callKeyedNonStrict(o) {
      return o[nonstrict_name]();
    }
    function callIndexedStrict(o) {
      return o[strict_number]();
    }
    function callIndexedNonStrict(o) {
      return o[nonstrict_number]();
    }
    function callStrictGet(o) {
      return o.strictget();
    }
    function callNonStrictGet(o) {
      return o.nonstrictget();
    }
    function callKeyedStrictGet(o) {
      return o[strict_name_get]();
    }
    function callKeyedNonStrictGet(o) {
      return o[nonstrict_name_get]();
    }
    function callIndexedStrictGet(o) {
      return o[strict_number_get]();
    }
    function callIndexedNonStrictGet(o) {
      return o[nonstrict_number_get]();
    }

    for (var i = 0; i < 10; i ++) {
      assertEquals(("hello").strict(), "string");
      assertEquals(("hello").nonstrict(), "object");
      assertEquals(("hello")[strict_name](), "string");
      assertEquals(("hello")[nonstrict_name](), "object");
      assertEquals(("hello")[strict_number](), "string");
      assertEquals(("hello")[nonstrict_number](), "object");

      assertEquals((10 + i).strict(), "number");
      assertEquals((10 + i).nonstrict(), "object");
      assertEquals((10 + i)[strict_name](), "number");
      assertEquals((10 + i)[nonstrict_name](), "object");
      assertEquals((10 + i)[strict_number](), "number");
      assertEquals((10 + i)[nonstrict_number](), "object");

      assertEquals((true).strict(), "boolean");
      assertEquals((true).nonstrict(), "object");
      assertEquals((true)[strict_name](), "boolean");
      assertEquals((true)[nonstrict_name](), "object");
      assertEquals((true)[strict_number](), "boolean");
      assertEquals((true)[nonstrict_number](), "object");

      assertEquals((false).strict(), "boolean");
      assertEquals((false).nonstrict(), "object");
      assertEquals((false)[strict_name](), "boolean");
      assertEquals((false)[nonstrict_name](), "object");
      assertEquals((false)[strict_number](), "boolean");
      assertEquals((false)[nonstrict_number](), "object");

      assertEquals(callStrict("howdy"), "string");
      assertEquals(callNonStrict("howdy"), "object");
      assertEquals(callKeyedStrict("howdy"), "string");
      assertEquals(callKeyedNonStrict("howdy"), "object");
      assertEquals(callIndexedStrict("howdy"), "string");
      assertEquals(callIndexedNonStrict("howdy"), "object");

      assertEquals(callStrict(17 + i), "number");
      assertEquals(callNonStrict(17 + i), "object");
      assertEquals(callKeyedStrict(17 + i), "number");
      assertEquals(callKeyedNonStrict(17 + i), "object");
      assertEquals(callIndexedStrict(17 + i), "number");
      assertEquals(callIndexedNonStrict(17 + i), "object");

      assertEquals(callStrict(true), "boolean");
      assertEquals(callNonStrict(true), "object");
      assertEquals(callKeyedStrict(true), "boolean");
      assertEquals(callKeyedNonStrict(true), "object");
      assertEquals(callIndexedStrict(true), "boolean");
      assertEquals(callIndexedNonStrict(true), "object");

      assertEquals(callStrict(false), "boolean");
      assertEquals(callNonStrict(false), "object");
      assertEquals(callKeyedStrict(false), "boolean");
      assertEquals(callKeyedNonStrict(false), "object");
      assertEquals(callIndexedStrict(false), "boolean");
      assertEquals(callIndexedNonStrict(false), "object");

      // All of the above, with getters
      assertEquals(("hello").strictget(), "string");
      assertEquals(("hello").nonstrictget(), "object");
      assertEquals(("hello")[strict_name_get](), "string");
      assertEquals(("hello")[nonstrict_name_get](), "object");
      assertEquals(("hello")[strict_number_get](), "string");
      assertEquals(("hello")[nonstrict_number_get](), "object");

      assertEquals((10 + i).strictget(), "number");
      assertEquals((10 + i).nonstrictget(), "object");
      assertEquals((10 + i)[strict_name_get](), "number");
      assertEquals((10 + i)[nonstrict_name_get](), "object");
      assertEquals((10 + i)[strict_number_get](), "number");
      assertEquals((10 + i)[nonstrict_number_get](), "object");

      assertEquals((true).strictget(), "boolean");
      assertEquals((true).nonstrictget(), "object");
      assertEquals((true)[strict_name_get](), "boolean");
      assertEquals((true)[nonstrict_name_get](), "object");
      assertEquals((true)[strict_number_get](), "boolean");
      assertEquals((true)[nonstrict_number_get](), "object");

      assertEquals((false).strictget(), "boolean");
      assertEquals((false).nonstrictget(), "object");
      assertEquals((false)[strict_name_get](), "boolean");
      assertEquals((false)[nonstrict_name_get](), "object");
      assertEquals((false)[strict_number_get](), "boolean");
      assertEquals((false)[nonstrict_number_get](), "object");

      assertEquals(callStrictGet("howdy"), "string");
      assertEquals(callNonStrictGet("howdy"), "object");
      assertEquals(callKeyedStrictGet("howdy"), "string");
      assertEquals(callKeyedNonStrictGet("howdy"), "object");
      assertEquals(callIndexedStrictGet("howdy"), "string");
      assertEquals(callIndexedNonStrictGet("howdy"), "object");

      assertEquals(callStrictGet(17 + i), "number");
      assertEquals(callNonStrictGet(17 + i), "object");
      assertEquals(callKeyedStrictGet(17 + i), "number");
      assertEquals(callKeyedNonStrictGet(17 + i), "object");
      assertEquals(callIndexedStrictGet(17 + i), "number");
      assertEquals(callIndexedNonStrictGet(17 + i), "object");

      assertEquals(callStrictGet(true), "boolean");
      assertEquals(callNonStrictGet(true), "object");
      assertEquals(callKeyedStrictGet(true), "boolean");
      assertEquals(callKeyedNonStrictGet(true), "object");
      assertEquals(callIndexedStrictGet(true), "boolean");
      assertEquals(callIndexedNonStrictGet(true), "object");

      assertEquals(callStrictGet(false), "boolean");
      assertEquals(callNonStrictGet(false), "object");
      assertEquals(callKeyedStrictGet(false), "boolean");
      assertEquals(callKeyedNonStrictGet(false), "object");
      assertEquals(callIndexedStrictGet(false), "boolean");
      assertEquals(callIndexedNonStrictGet(false), "object");

    }
  } finally {
    // Cleanup
    cleanup(String);
    cleanup(Number);
    cleanup(Boolean);
  }
})();


(function ObjectEnvironment() {
  var o = {};
  Object.defineProperty(o, "foo", { value: "FOO", writable: false });
  assertThrows(
    function () {
      with (o) {
        (function() {
          "use strict";
          foo = "Hello";
        })();
      }
    },
    TypeError);
})();


(function TestSetPropertyWithoutSetter() {
  var o = { get foo() { return "Yey"; } };
  assertThrows(
    function broken() {
      "use strict";
      o.foo = (0xBADBAD00 >> 1);
    },
    TypeError);
})();


(function TestSetPropertyNonConfigurable() {
  var frozen = Object.freeze({});
  var sealed = Object.seal({});

  function strict(o) {
    "use strict";
    o.property = "value";
  }

  assertThrows(function() { strict(frozen); }, TypeError);
  assertThrows(function() { strict(sealed); }, TypeError);
})();


(function TestAssignmentToReadOnlyProperty() {
  "use strict";

  var o = {};
  Object.defineProperty(o, "property", { value: 7 });

  assertThrows(function() { o.property = "new value"; }, TypeError);
  assertThrows(function() { o.property += 10; }, TypeError);
  assertThrows(function() { o.property -= 10; }, TypeError);
  assertThrows(function() { o.property *= 10; }, TypeError);
  assertThrows(function() { o.property /= 10; }, TypeError);
  assertThrows(function() { o.property++; }, TypeError);
  assertThrows(function() { o.property--; }, TypeError);
  assertThrows(function() { ++o.property; }, TypeError);
  assertThrows(function() { --o.property; }, TypeError);

  var name = "prop" + "erty"; // to avoid symbol path.
  assertThrows(function() { o[name] = "new value"; }, TypeError);
  assertThrows(function() { o[name] += 10; }, TypeError);
  assertThrows(function() { o[name] -= 10; }, TypeError);
  assertThrows(function() { o[name] *= 10; }, TypeError);
  assertThrows(function() { o[name] /= 10; }, TypeError);
  assertThrows(function() { o[name]++; }, TypeError);
  assertThrows(function() { o[name]--; }, TypeError);
  assertThrows(function() { ++o[name]; }, TypeError);
  assertThrows(function() { --o[name]; }, TypeError);

  assertEquals(o.property, 7);
})();


(function TestAssignmentToReadOnlyLoop() {
  var name = "prop" + "erty"; // to avoid symbol path.
  var o = {};
  Object.defineProperty(o, "property", { value: 7 });

  function strict(o, name) {
    "use strict";
    o[name] = "new value";
  }

  for (var i = 0; i < 10; i ++) {
    var exception = false;
    try {
      strict(o, name);
    } catch(e) {
      exception = true;
      assertInstanceof(e, TypeError);
    }
    assertTrue(exception);
  }
})();


// Specialized KeyedStoreIC experiencing miss.
(function testKeyedStoreICStrict() {
  var o = [9,8,7,6,5,4,3,2,1];

  function test(o, i, v) {
    "use strict";
    o[i] = v;
  }

  for (var i = 0; i < 10; i ++) {
    test(o, 5, 17);        // start specialized for smi indices
    assertEquals(o[5], 17);
    test(o, "a", 19);
    assertEquals(o["a"], 19);
    test(o, "5", 29);
    assertEquals(o[5], 29);
    test(o, 100000, 31);
    assertEquals(o[100000], 31);
  }
})();


(function TestSetElementWithoutSetter() {
  "use strict";

  var o = { };
  Object.defineProperty(o, 0, { get : function() { } });

  var zero_smi = 0;
  var zero_number = new Number(0);
  var zero_symbol = "0";
  var zero_string = "-0-".substring(1,2);

  assertThrows(function() { o[zero_smi] = "new value"; }, TypeError);
  assertThrows(function() { o[zero_number] = "new value"; }, TypeError);
  assertThrows(function() { o[zero_symbol] = "new value"; }, TypeError);
  assertThrows(function() { o[zero_string] = "new value"; }, TypeError);
})();


(function TestSetElementNonConfigurable() {
  "use strict";
  var frozen = Object.freeze({});
  var sealed = Object.seal({});

  var zero_number = 0;
  var zero_symbol = "0";
  var zero_string = "-0-".substring(1,2);

  assertThrows(function() { frozen[zero_number] = "value"; }, TypeError);
  assertThrows(function() { sealed[zero_number] = "value"; }, TypeError);
  assertThrows(function() { frozen[zero_symbol] = "value"; }, TypeError);
  assertThrows(function() { sealed[zero_symbol] = "value"; }, TypeError);
  assertThrows(function() { frozen[zero_string] = "value"; }, TypeError);
  assertThrows(function() { sealed[zero_string] = "value"; }, TypeError);
})();


(function TestAssignmentToReadOnlyElement() {
  "use strict";

  var o = {};
  Object.defineProperty(o, 7, { value: 17 });

  var seven_smi = 7;
  var seven_number = new Number(7);
  var seven_symbol = "7";
  var seven_string = "-7-".substring(1,2);

  // Index with number.
  assertThrows(function() { o[seven_smi] = "value"; }, TypeError);
  assertThrows(function() { o[seven_smi] += 10; }, TypeError);
  assertThrows(function() { o[seven_smi] -= 10; }, TypeError);
  assertThrows(function() { o[seven_smi] *= 10; }, TypeError);
  assertThrows(function() { o[seven_smi] /= 10; }, TypeError);
  assertThrows(function() { o[seven_smi]++; }, TypeError);
  assertThrows(function() { o[seven_smi]--; }, TypeError);
  assertThrows(function() { ++o[seven_smi]; }, TypeError);
  assertThrows(function() { --o[seven_smi]; }, TypeError);

  assertThrows(function() { o[seven_number] = "value"; }, TypeError);
  assertThrows(function() { o[seven_number] += 10; }, TypeError);
  assertThrows(function() { o[seven_number] -= 10; }, TypeError);
  assertThrows(function() { o[seven_number] *= 10; }, TypeError);
  assertThrows(function() { o[seven_number] /= 10; }, TypeError);
  assertThrows(function() { o[seven_number]++; }, TypeError);
  assertThrows(function() { o[seven_number]--; }, TypeError);
  assertThrows(function() { ++o[seven_number]; }, TypeError);
  assertThrows(function() { --o[seven_number]; }, TypeError);

  assertThrows(function() { o[seven_symbol] = "value"; }, TypeError);
  assertThrows(function() { o[seven_symbol] += 10; }, TypeError);
  assertThrows(function() { o[seven_symbol] -= 10; }, TypeError);
  assertThrows(function() { o[seven_symbol] *= 10; }, TypeError);
  assertThrows(function() { o[seven_symbol] /= 10; }, TypeError);
  assertThrows(function() { o[seven_symbol]++; }, TypeError);
  assertThrows(function() { o[seven_symbol]--; }, TypeError);
  assertThrows(function() { ++o[seven_symbol]; }, TypeError);
  assertThrows(function() { --o[seven_symbol]; }, TypeError);

  assertThrows(function() { o[seven_string] = "value"; }, TypeError);
  assertThrows(function() { o[seven_string] += 10; }, TypeError);
  assertThrows(function() { o[seven_string] -= 10; }, TypeError);
  assertThrows(function() { o[seven_string] *= 10; }, TypeError);
  assertThrows(function() { o[seven_string] /= 10; }, TypeError);
  assertThrows(function() { o[seven_string]++; }, TypeError);
  assertThrows(function() { o[seven_string]--; }, TypeError);
  assertThrows(function() { ++o[seven_string]; }, TypeError);
  assertThrows(function() { --o[seven_string]; }, TypeError);

  assertEquals(o[seven_number], 17);
  assertEquals(o[seven_symbol], 17);
  assertEquals(o[seven_string], 17);
})();


(function TestAssignmentToReadOnlyLoop() {
  "use strict";

  var o = {};
  Object.defineProperty(o, 7, { value: 17 });

  var seven_smi = 7;
  var seven_number = new Number(7);
  var seven_symbol = "7";
  var seven_string = "-7-".substring(1,2);

  for (var i = 0; i < 10; i ++) {
    assertThrows(function() { o[seven_smi] = "value" }, TypeError);
    assertThrows(function() { o[seven_number] = "value" }, TypeError);
    assertThrows(function() { o[seven_symbol] = "value" }, TypeError);
    assertThrows(function() { o[seven_string] = "value" }, TypeError);
  }

  assertEquals(o[7], 17);
})();


(function TestAssignmentToStringLength() {
  "use strict";

  var str_val = "string";
  var str_obj = new String(str_val);
  var str_cat = str_val + str_val + str_obj;

  assertThrows(function() { str_val.length = 1; }, TypeError);
  assertThrows(function() { str_obj.length = 1; }, TypeError);
  assertThrows(function() { str_cat.length = 1; }, TypeError);
})();


(function TestArgumentsAliasing() {
  function strict(a, b) {
    "use strict";
    a = "c";
    b = "d";
    return [a, b, arguments[0], arguments[1]];
  }

  function nonstrict(a, b) {
    a = "c";
    b = "d";
    return [a, b, arguments[0], arguments[1]];
  }

  assertEquals(["c", "d", "a", "b"], strict("a", "b"));
  assertEquals(["c", "d", "c", "d"], nonstrict("a", "b"));
})();


function CheckPillDescriptor(func, name) {

  function CheckPill(pill) {
    assertEquals("function", typeof pill);
    assertInstanceof(pill, Function);
    pill.property = "value";
    assertEquals(pill.value, undefined);
    assertThrows(function() { 'use strict'; pill.property = "value"; },
                 TypeError);
    assertThrows(pill, TypeError);
    assertEquals(pill.prototype, (function(){}).prototype);
    var d = Object.getOwnPropertyDescriptor(pill, "prototype");
    assertFalse(d.writable);
    assertFalse(d.configurable);
    assertFalse(d.enumerable);
  }

  var descriptor = Object.getOwnPropertyDescriptor(func, name);
  CheckPill(descriptor.get)
  CheckPill(descriptor.set);
  assertFalse(descriptor.enumerable);
  assertFalse(descriptor.configurable);
}


(function TestStrictFunctionPills() {
  function strict() {
    "use strict";
  }
  assertThrows(function() { strict.caller; }, TypeError);
  assertThrows(function() { strict.arguments; }, TypeError);

  var another = new Function("'use strict'");
  assertThrows(function() { another.caller; }, TypeError);
  assertThrows(function() { another.arguments; }, TypeError);

  var third = (function() { "use strict"; return function() {}; })();
  assertThrows(function() { third.caller; }, TypeError);
  assertThrows(function() { third.arguments; }, TypeError);

  CheckPillDescriptor(strict, "caller");
  CheckPillDescriptor(strict, "arguments");
  CheckPillDescriptor(another, "caller");
  CheckPillDescriptor(another, "arguments");
  CheckPillDescriptor(third, "caller");
  CheckPillDescriptor(third, "arguments");
})();


(function TestStrictFunctionWritablePrototype() {
  "use strict";
  function TheClass() {
  }
  assertThrows(function() { TheClass.caller; }, TypeError);
  assertThrows(function() { TheClass.arguments; }, TypeError);

  // Strict functions must have writable prototype.
  TheClass.prototype = {
    func: function() { return "func_value"; },
    get accessor() { return "accessor_value"; },
    property: "property_value",
  };

  var o = new TheClass();
  assertEquals(o.func(), "func_value");
  assertEquals(o.accessor, "accessor_value");
  assertEquals(o.property, "property_value");
})();


(function TestStrictArgumentPills() {
  function strict() {
    "use strict";
    return arguments;
  }

  var args = strict();
  CheckPillDescriptor(args, "caller");
  CheckPillDescriptor(args, "callee");

  args = strict(17, "value", strict);
  assertEquals(17, args[0])
  assertEquals("value", args[1])
  assertEquals(strict, args[2]);
  CheckPillDescriptor(args, "caller");
  CheckPillDescriptor(args, "callee");

  function outer() {
    "use strict";
    function inner() {
      return arguments;
    }
    return inner;
  }

  var args = outer()();
  CheckPillDescriptor(args, "caller");
  CheckPillDescriptor(args, "callee");

  args = outer()(17, "value", strict);
  assertEquals(17, args[0])
  assertEquals("value", args[1])
  assertEquals(strict, args[2]);
  CheckPillDescriptor(args, "caller");
  CheckPillDescriptor(args, "callee");
})();


(function TestNonStrictFunctionCallerPillSimple() {
  function return_my_caller() {
    return return_my_caller.caller;
  }

  function strict() {
    "use strict";
    return_my_caller();
  }
  assertThrows(strict, TypeError);

  function non_strict() {
    return return_my_caller();
  }
  assertSame(non_strict(), non_strict);
})();


(function TestNonStrictFunctionCallerPill() {
  function strict(n) {
    "use strict";
    non_strict(n);
  }

  function recurse(n, then) {
    if (n > 0) {
      recurse(n - 1);
    } else {
      return then();
    }
  }

  function non_strict(n) {
    recurse(n, function() { non_strict.caller; });
  }

  function test(n) {
    try {
      recurse(n, function() { strict(n); });
    } catch(e) {
      return e instanceof TypeError;
    }
    return false;
  }

  for (var i = 0; i < 10; i ++) {
    assertEquals(test(i), true);
  }
})();


(function TestStrictModeEval() {
  "use strict";
  eval("var eval_local = 10;");
  assertThrows(function() { return eval_local; }, ReferenceError);
})();