[strong] Implement static restrictions on binding/assignment to 'undefined' identifier.

test/mjsunit/strong/undefined.js

Index: test/mjsunit/strong/undefined.js
diff --git a/test/mjsunit/strong/undefined.js b/test/mjsunit/strong/undefined.js
new file mode 100644
index 0000000000000000000000000000000000000000..275e2ab0209411299a249b60d035f0d4fbc8cf2e
--- /dev/null
+++ b/test/mjsunit/strong/undefined.js
@@ -0,0 +1,104 @@
+// Copyright 2014 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: --strong-mode
+
+//repurposing the strict mode 'eval' and 'arguments' tests to test for correct

[rossberg, 2015/04/08 11:30:11]

Style nit: Spaces after // (here and below). Also, upper case.

[conradw, 2015/04/09 12:24:17]

Done.

+//behaviour of 'undefined' as an identifier in strong mode

[rossberg, 2015/04/08 11:30:11]

Please add tests for:

- bindings to undefined (var, let, const)
- bindings in for-loops (for, for-in, for-of)
- function expressions
- arrow function parameters
- classes named undefined (declarations, expressions)

[conradw, 2015/04/09 12:24:17]

Done.

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

[rossberg, 2015/04/08 11:30:11]

We also should have test contexts that are (strict or strong) classes.

More importantly, test contexts where the 'use strong' is _inside_ the function
(or class) you are checking. For example, to cover

  function undefined() { 'use strong'; }
  function(undefined) { 'use strong'; }
  class undefined { 'use strong'; }

etc. Though I'm not sure what the best generalisation of the CheckStrongMode
helper is to support that.

[conradw, 2015/04/09 12:24:17]

Done.

+
+function CheckFunctionConstructorStrongMode() {
+  var args = [];
+  for (var i = 0; i < arguments.length; i ++) {

[rossberg, 2015/04/08 11:30:11]

With adding --harmony-rest-parameters to Flags you should now be able to say

function CheckFunctionConstructorStrongMode(...args)

and drop the loop.

[conradw, 2015/04/09 12:24:17]

Acknowledged.

+    args[i] = arguments[i];
+  }
+  // Create non-strong function. No exception.
+  args[arguments.length] = "";
+  assertDoesNotThrow(function() {
+    Function.apply(this, args);
+  });
+  // Create strong mode function. Exception expected.
+  args[arguments.length] = "'use strong';";
+  assertThrows(function() {
+    Function.apply(this, args);
+  }, SyntaxError);
+}
+
+//Function named 'undefined'.
+CheckStrongMode("function undefined() {}", SyntaxError);
+
+// Function parameter named 'undefined'.
+CheckStrongMode("function foo(a, b, undefined, c, d) {}", SyntaxError);
+
+// Property accessor parameter named 'undefined'.
+CheckStrongMode("let o = { set foo(undefined) {} }", SyntaxError);
+
+//Function constructor: 'undefined' parameter name.
+CheckFunctionConstructorStrongMode("undefined");
+
+//catch(undefined)
+CheckStrongMode("try{}catch(undefined){};", SyntaxError);
+
+//Assignment to undefined
+CheckStrongMode("function strong() { undefined = undefined; }", SyntaxError);
+CheckStrongMode("function strong() { print(undefined = undefined); }", SyntaxError);

[rossberg, 2015/04/08 11:30:11]

Style nit: line length (here and below)

[conradw, 2015/04/09 12:24:17]

Done.

+CheckStrongMode("function strong() { let x = undefined = undefined; }", SyntaxError);
+
+// Compound assignment to undefined
+CheckStrongMode("function strong() { undefined *= undefined; }", SyntaxError);
+CheckStrongMode("function strong() { undefined /= undefined; }", SyntaxError);
+CheckStrongMode("function strong() { print(undefined %= undefined); }", SyntaxError);
+CheckStrongMode("function strong() { let x = undefined += undefined; }",
+                SyntaxError);
+CheckStrongMode("function strong() { let x = undefined -= undefined; }",
+                SyntaxError);
+CheckStrongMode("function strong() { undefined <<= undefined; }", SyntaxError);
+CheckStrongMode("function strong() { undefined >>= undefined; }", SyntaxError);
+CheckStrongMode("function strong() { print(undefined >>>= undefined); }",
+                SyntaxError);
+CheckStrongMode("function strong() { print(undefined &= undefined); }",
+                SyntaxError);
+CheckStrongMode("function strong() { let x = undefined ^= undefined; }",
+                SyntaxError);
+CheckStrongMode("function strong() { let x = undefined |= undefined; }",
+                SyntaxError);
+
+// Postfix increment with undefined
+CheckStrongMode("function strong() { undefined++; }", SyntaxError);
+CheckStrongMode("function strong() { print(undefined++); }", SyntaxError);
+CheckStrongMode("function strong() { let x = undefined++; }", SyntaxError);
+
+// Postfix decrement with undefined
+CheckStrongMode("function strong() { undefined--; }", SyntaxError);
+CheckStrongMode("function strong() { print(undefined--); }", SyntaxError);
+CheckStrongMode("function strong() { let x = undefined--; }", SyntaxError);
+
+// Prefix increment with undefined
+CheckStrongMode("function strong() { ++undefined; }", SyntaxError);
+CheckStrongMode("function strong() { print(++undefined); }", SyntaxError);
+CheckStrongMode("function strong() { let x = ++undefined; }", SyntaxError);
+
+// Prefix decrement with undefined
+CheckStrongMode("function strong() { --undefined; }", SyntaxError);
+CheckStrongMode("function strong() { print(--undefined); }", SyntaxError);
+CheckStrongMode("function strong() { let x = --undefined; }", SyntaxError);