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

test/mjsunit/strong/undefined.js

+// 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 --harmony-sloppy --harmony-arrow-functions
+
+// Repurposing the strict mode 'eval' and 'arguments' tests to test for correct
+// behaviour of 'undefined' as an identifier in strong mode.
+"use strict";
+
+function CheckStrongMode(code) {
+  assertThrows("'use strict'; " + code + "; throw new TypeError();", TypeError);

[rossberg, 2015/04/10 07:31:28]

I think you can drop these 3 lines now, they are already induced by the loops
below (or can be, for the last one).

[conradw, 2015/04/10 11:02:06]

Done.

+  assertThrows("'use strong'; " + code, SyntaxError);
+  assertThrows('"use strong"; ' + code, SyntaxError);
+
+  let strictContexts = [
+    ["'use strict';", ""],
+    ["function outer() { 'use strict';", "}"],
+    ["function outer() { 'use strict'; function inner() {", "}}"],
+    ["class C { m() {", "} }"]
+  ]
+  let strongContexts = [
+    ["'use strong';", ""],
+    ["function outer() { 'use strong';", "}"],
+    ["function outer() { 'use strong'; function inner() {", "}}"],
+    ["class C { m() { 'use strong';", "} }"]
+  ]
+
+  for (let context of strictContexts) {
+    assertThrows(context[0] + code + context[1] + "; throw new TypeError()",
+                 TypeError);
+  }
+  for (let context of strongContexts) {
+    assertThrows(context[0] + code + context[1], SyntaxError);
+  }
+}
+
+// Binding 'undefined'
+CheckStrongMode("var undefined;");
+CheckStrongMode("let undefined;");
+CheckStrongMode("var undefined = 0;");
+CheckStrongMode("let undefined = 0;");
+CheckStrongMode("const undefined = 0;");
+CheckStrongMode("var x, y = 0, undefined;");
+CheckStrongMode("let x, y = 0, undefined;");
+
+// Function named 'undefined'.
+CheckStrongMode("function undefined() {}");
+assertThrows("function undefined() {'use strong';}", SyntaxError);
+
+// Generator Function named 'undefined';
+CheckStrongMode("function* undefined() {}");
+assertThrows("function* undefined() {'use strong';}", SyntaxError);
+
+// FunctionExpression named 'undefined';
+CheckStrongMode("(function undefined() {})");
+assertThrows("(function undefined() {'use strong';})", SyntaxError);
+
+// Generator function expression named 'undefined';
+CheckStrongMode("(function* undefined() {})");
+assertThrows("(function* undefined() {'use strong';})", SyntaxError);
+
+//Function parameter named 'undefined'.
+CheckStrongMode("function foo(a, b, undefined, c, d) {}");
+assertThrows("function foo(a, b, undefined, c, d) {'use strong';}",
+             SyntaxError);
+assertThrows("(function foo(a, b, undefined, c, d) {'use strong';})",
+  SyntaxError);
+assertThrows("class C { foo(a, b, undefined, c, d) {'use strong';} }",

[rossberg, 2015/04/10 07:31:28]

Also add a case for methods in object literals:

  ({ foo(...) {...} })

Similarly for generator methods.

[conradw, 2015/04/10 11:02:05]

Done.

+             SyntaxError);
+
+// Generator function parameter named 'undefined'.
+CheckStrongMode("function* foo(a, b, undefined, c, d) {}");
+assertThrows("function* foo(a, b, undefined, c, d) {'use strong';}",
+  SyntaxError);
+assertThrows("(function* foo(a, b, undefined, c, d) {'use strong';})",
+SyntaxError);
+assertThrows("class C { *foo(a, b, undefined, c, d) {'use strong';} }",
+  SyntaxError);
+
+// Arrow function expression with 'undefined' param
+// TODO(conradw): Checking arrow function heads is hard to modify just now
+// CheckStrongMode("(undefined => {return})");
+// assertThrows("(undefined => {'use strong';})");
+
+// Class declaration named 'undefined'
+CheckStrongMode("class undefined {}");
+assertThrows("class undefined {'use strong'}", SyntaxError);
+
+//ClassExpression named 'undefined'
+CheckStrongMode("(class undefined {})");
+assertThrows("(class undefined {'use strong'})", SyntaxError);
+
+// Binding/assigning to 'undefined' in for
+CheckStrongMode("for(undefined = 0;false;);");
+CheckStrongMode("for(var undefined = 0;false;);");
+CheckStrongMode("for(let undefined = 0;false;);");
+CheckStrongMode("for(const undefined = 0;false;);");
+
+// Binding/assigning to 'undefined' in for-in
+CheckStrongMode("for(undefined in {});");
+CheckStrongMode("for(var undefined in {});");
+CheckStrongMode("for(let undefined in {});");
+CheckStrongMode("for(const undefined in {});");
+
+// Binding/assigning to 'undefined' in for-of
+CheckStrongMode("for(undefined of []);");
+CheckStrongMode("for(var undefined of []);");
+CheckStrongMode("for(let undefined of []);");
+CheckStrongMode("for(const undefined of []);");
+
+// Property accessor parameter named 'undefined'.
+CheckStrongMode("let o = { set foo(undefined) {} }");
+assertThrows("let o = { set foo(undefined) {'use strong';} }", SyntaxError);
+
+// catch(undefined)
+CheckStrongMode("try {} catch(undefined) {};");
+
+// Assignment to undefined
+CheckStrongMode("undefined = 0;");
+CheckStrongMode("print(undefined = 0);");
+CheckStrongMode("let x = undefined = 0;");
+
+// Compound assignment to undefined
+CheckStrongMode("undefined *= 0;");
+CheckStrongMode("undefined /= 0;");
+CheckStrongMode("print(undefined %= 0);");
+CheckStrongMode("let x = undefined += 0;");
+CheckStrongMode("let x = undefined -= 0;");
+CheckStrongMode("undefined <<= 0;");
+CheckStrongMode("undefined >>= 0;");
+CheckStrongMode("print(undefined >>>= 0);");
+CheckStrongMode("print(undefined &= 0);");
+CheckStrongMode("let x = undefined ^= 0;");
+CheckStrongMode("let x = undefined |= 0;");
+
+// Postfix increment with undefined
+CheckStrongMode("undefined++;");
+CheckStrongMode("print(undefined++);");
+CheckStrongMode("let x = undefined++;");
+
+// Postfix decrement with undefined
+CheckStrongMode("undefined--;");
+CheckStrongMode("print(undefined--);");
+CheckStrongMode("let x = undefined--;");
+
+// Prefix increment with undefined
+CheckStrongMode("++undefined;");
+CheckStrongMode("print(++undefined);");
+CheckStrongMode("let x = ++undefined;");
+
+// Prefix decrement with undefined
+CheckStrongMode("--undefined;");
+CheckStrongMode("print(--undefined);");
+CheckStrongMode("let x = --undefined;");
+
+// Function constructor: 'undefined' parameter name.
+assertDoesNotThrow(function() {
+  Function("undefined", "");
+});
+assertThrows(function() {
+  Function("undefined", "'use strong';");
+}, SyntaxError);