Add m-esr52 at 52.6.0

12 files changed, 673 insertions, 0 deletions

diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/.eslintrc.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/.eslintrc.js
new file mode 100644
index 000000000..505a3ea82
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/.eslintrc.js
@@ -0,0 +1,51 @@
+"use strict";
+
+/**
+ * Based on npm coding standards at https://docs.npmjs.com/misc/coding-style.
+ *
+ * The places we differ from the npm coding style:
+ *   - Commas should be at the end of a line.
+ *   - Always use semicolons.
+ *   - Functions should not have whitespace before params.
+ */
+
+module.exports = {
+  "env": {
+    "node": true
+  },
+
+  "rules": {
+    "brace-style": ["error", "1tbs"],
+    "camelcase": "error",
+    "comma-dangle": ["error", "never"],
+    "comma-spacing": "error",
+    "comma-style": ["error", "last"],
+    "curly": ["error", "multi-line"],
+    "handle-callback-err": ["error", "er"],
+    "indent": ["error", 2, {"SwitchCase": 1}],
+    "max-len": ["error", 80, "error"],
+    "no-multiple-empty-lines": ["error", {"max": 1}],
+    "no-undef": "error",
+    "no-undef-init": "error",
+    "no-unexpected-multiline": "error",
+    "object-curly-spacing": "off",
+    "one-var": ["error", "never"],
+    "operator-linebreak": ["error", "after"],
+    "semi": ["error", "always"],
+    "space-before-blocks": "error",
+    "space-before-function-paren": ["error", "never"],
+    "keyword-spacing": "error",
+    "strict": ["error", "global"],
+  },
+
+  // Globals accessible within node modules.
+  "globals": {
+    "DTRACE_HTTP_CLIENT_REQUEST": true,
+    "DTRACE_HTTP_CLIENT_RESPONSE": true,
+    "DTRACE_HTTP_SERVER_REQUEST": true,
+    "DTRACE_HTTP_SERVER_RESPONSE": true,
+    "DTRACE_NET_SERVER_CONNECTION": true,
+    "DTRACE_NET_STREAM_END": true,
+    "Intl": true,
+  },
+};
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/balanced-listeners.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/balanced-listeners.js
new file mode 100644
index 000000000..c658a6b44
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/balanced-listeners.js
@@ -0,0 +1,113 @@
+/**

+ * @fileoverview Check that there's a removeEventListener for each

+ * addEventListener and an off for each on.

+ * Note that for now, this rule is rather simple in that it only checks that

+ * for each event name there is both an add and remove listener. It doesn't

+ * check that these are called on the right objects or with the same callback.

+ *

+ * This Source Code Form is subject to the terms of the Mozilla Public

+ * License, v. 2.0. If a copy of the MPL was not distributed with this

+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.

+ */

+

+"use strict";

+

+// -----------------------------------------------------------------------------

+// Rule Definition

+// -----------------------------------------------------------------------------

+

+module.exports = function(context) {

+  // ---------------------------------------------------------------------------

+  // Helpers

+  // ---------------------------------------------------------------------------

+

+  var DICTIONARY = {

+    "addEventListener": "removeEventListener",

+    "on": "off"

+  };

+  // Invert this dictionary to make it easy later.

+  var INVERTED_DICTIONARY = {};

+  for (var i in DICTIONARY) {

+    INVERTED_DICTIONARY[DICTIONARY[i]] = i;

+  }

+

+  // Collect the add/remove listeners in these 2 arrays.

+  var addedListeners = [];

+  var removedListeners = [];

+

+  function addAddedListener(node) {

+    addedListeners.push({

+      functionName: node.callee.property.name,

+      type: node.arguments[0].value,

+      node: node.callee.property,

+      useCapture: node.arguments[2] ? node.arguments[2].value : null

+    });

+  }

+

+  function addRemovedListener(node) {

+    removedListeners.push({

+      functionName: node.callee.property.name,

+      type: node.arguments[0].value,

+      useCapture: node.arguments[2] ? node.arguments[2].value : null

+    });

+  }

+

+  function getUnbalancedListeners() {

+    var unbalanced = [];

+

+    for (var j = 0; j < addedListeners.length; j++) {

+      if (!hasRemovedListener(addedListeners[j])) {

+        unbalanced.push(addedListeners[j]);

+      }

+    }

+    addedListeners = removedListeners = [];

+

+    return unbalanced;

+  }

+

+  function hasRemovedListener(addedListener) {

+    for (var k = 0; k < removedListeners.length; k++) {

+      var listener = removedListeners[k];

+      if (DICTIONARY[addedListener.functionName] === listener.functionName &&

+          addedListener.type === listener.type &&

+          addedListener.useCapture === listener.useCapture) {

+        return true;

+      }

+    }

+

+    return false;

+  }

+

+  // ---------------------------------------------------------------------------

+  // Public

+  // ---------------------------------------------------------------------------

+

+  return {

+    CallExpression: function(node) {

+      if (node.arguments.length === 0) {

+        return;

+      }

+

+      if (node.callee.type === "MemberExpression") {

+        var listenerMethodName = node.callee.property.name;

+

+        if (DICTIONARY.hasOwnProperty(listenerMethodName)) {

+          addAddedListener(node);

+        } else if (INVERTED_DICTIONARY.hasOwnProperty(listenerMethodName)) {

+          addRemovedListener(node);

+        }

+      }

+    },

+

+    "Program:exit": function() {

+      getUnbalancedListeners().forEach(function(listener) {

+        context.report(listener.node,

+          "No corresponding '{{functionName}}({{type}})' was found.",

+          {

+            functionName: DICTIONARY[listener.functionName],

+            type: listener.type

+          });

+      });

+    }

+  };

+};

diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-browserjs-globals.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-browserjs-globals.js
new file mode 100644
index 000000000..313af2d71
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-browserjs-globals.js
@@ -0,0 +1,83 @@
+/**
+ * @fileoverview Import globals from browser.js.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+var fs = require("fs");
+var path = require("path");
+var helpers = require("../helpers");
+var globals = require("../globals");
+
+const SCRIPTS = [
+  //"browser/base/content/nsContextMenu.js",
+  "toolkit/content/contentAreaUtils.js",
+  "browser/components/places/content/editBookmarkOverlay.js",
+  "toolkit/components/printing/content/printUtils.js",
+  "toolkit/content/viewZoomOverlay.js",
+  "browser/components/places/content/browserPlacesViews.js",
+  "browser/base/content/browser.js",
+  "browser/components/downloads/content/downloads.js",
+  "browser/components/downloads/content/indicator.js",
+  "browser/components/customizableui/content/panelUI.js",
+  "toolkit/components/viewsource/content/viewSourceUtils.js",
+  "browser/base/content/browser-addons.js",
+  "browser/base/content/browser-ctrlTab.js",
+  "browser/base/content/browser-customization.js",
+  "browser/base/content/browser-devedition.js",
+  "browser/base/content/browser-feeds.js",
+  "browser/base/content/browser-fullScreenAndPointerLock.js",
+  "browser/base/content/browser-fullZoom.js",
+  "browser/base/content/browser-gestureSupport.js",
+  "browser/base/content/browser-media.js",
+  "browser/base/content/browser-places.js",
+  "browser/base/content/browser-plugins.js",
+  "browser/base/content/browser-refreshblocker.js",
+  "browser/base/content/browser-safebrowsing.js",
+  "browser/base/content/browser-sidebar.js",
+  "browser/base/content/browser-social.js",
+  "browser/base/content/browser-syncui.js",
+  "browser/base/content/browser-tabsintitlebar.js",
+  "browser/base/content/browser-thumbnails.js",
+  "browser/base/content/browser-trackingprotection.js",
+  "browser/base/content/browser-data-submission-info-bar.js",
+  "browser/base/content/browser-fxaccounts.js"
+];
+
+module.exports = function(context) {
+  return {
+    Program: function(node) {
+      if (helpers.getTestType(this) != "browser" &&
+          !helpers.getIsHeadFile(this)) {
+        return;
+      }
+
+      let filepath = helpers.getAbsoluteFilePath(context);
+      let root = helpers.getRootDir(filepath);
+      for (let script of SCRIPTS) {
+        let fileName = path.join(root, script);
+        try {
+          let newGlobals = globals.getGlobalsForFile(fileName);
+          helpers.addGlobals(newGlobals, context.getScope());
+        } catch (e) {
+          context.report(
+            node,
+            "Could not load globals from file {{filePath}}: {{error}}",
+            {
+              filePath: path.relative(root, fileName),
+              error: e
+            }
+          );
+        }
+      }
+    }
+  };
+};
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-globals.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-globals.js
new file mode 100644
index 000000000..053a9e702
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-globals.js
@@ -0,0 +1,15 @@
+/**
+ * @fileoverview Discovers all globals for the current file.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+module.exports = require("../globals").getESLintGlobalParser;
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-headjs-globals.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-headjs-globals.js
new file mode 100644
index 000000000..783642f58
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-headjs-globals.js
@@ -0,0 +1,49 @@
+/**
+ * @fileoverview Import globals from head.js and from any files that were
+ * imported by head.js (as far as we can correctly resolve the path).
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+var fs = require("fs");
+var path = require("path");
+var helpers = require("../helpers");
+var globals = require("../globals");
+
+module.exports = function(context) {
+
+  function importHead(path, node) {
+    try {
+      let stats = fs.statSync(path);
+      if (!stats.isFile()) {
+        return;
+      }
+    } catch (e) {
+      return;
+    }
+
+    let newGlobals = globals.getGlobalsForFile(path);
+    helpers.addGlobals(newGlobals, context.getScope());
+  }
+
+  // ---------------------------------------------------------------------------
+  // Public
+  // ---------------------------------------------------------------------------
+
+  return {
+    Program: function(node) {
+      let heads = helpers.getTestHeadFiles(this);
+      for (let head of heads) {
+        importHead(head, node);
+      }
+    }
+  };
+};
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/mark-test-function-used.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/mark-test-function-used.js
new file mode 100644
index 000000000..b2e8ec294
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/mark-test-function-used.js
@@ -0,0 +1,37 @@
+/**
+ * @fileoverview Simply marks `test` (the test method) or `run_test` as used when
+ * in mochitests or xpcshell tests respectively. This avoids ESLint telling us
+ * that the function is never called.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+var helpers = require("../helpers");
+
+module.exports = function(context) {
+  // ---------------------------------------------------------------------------
+  // Public
+  // ---------------------------------------------------------------------------
+
+  return {
+    Program: function() {
+      if (helpers.getTestType(this) == "browser") {
+        context.markVariableAsUsed("test");
+        return;
+      }
+
+      if (helpers.getTestType(this) == "xpcshell") {
+        context.markVariableAsUsed("run_test");
+        return;
+      }
+    }
+  };
+};
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-aArgs.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-aArgs.js
new file mode 100644
index 000000000..267f6836f
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-aArgs.js
@@ -0,0 +1,55 @@
+/**

+ * @fileoverview warns against using hungarian notation in function arguments

+ * (i.e. aArg).

+ *

+ * This Source Code Form is subject to the terms of the Mozilla Public

+ * License, v. 2.0. If a copy of the MPL was not distributed with this

+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.

+ */

+

+"use strict";

+

+// -----------------------------------------------------------------------------

+// Rule Definition

+// -----------------------------------------------------------------------------

+

+module.exports = function(context) {

+  // ---------------------------------------------------------------------------

+  // Helpers

+  // ---------------------------------------------------------------------------

+

+  function isPrefixed(name) {

+    return name.length >= 2 && /^a[A-Z]/.test(name);

+  }

+

+  function deHungarianize(name) {

+    return name.substring(1, 2).toLowerCase() +

+           name.substring(2, name.length);

+  }

+

+  function checkFunction(node) {

+    for (var i = 0; i < node.params.length; i++) {

+      var param = node.params[i];

+      if (param.name && isPrefixed(param.name)) {

+        var errorObj = {

+          name: param.name,

+          suggestion: deHungarianize(param.name)

+        };

+        context.report(param,

+                       "Parameter '{{name}}' uses Hungarian Notation, " +

+                       "consider using '{{suggestion}}' instead.",

+                       errorObj);

+      }

+    }

+  }

+

+  // ---------------------------------------------------------------------------

+  // Public

+  // ---------------------------------------------------------------------------

+

+  return {

+    "FunctionDeclaration": checkFunction,

+    "ArrowFunctionExpression": checkFunction,

+    "FunctionExpression": checkFunction

+  };

+};

diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-cpows-in-tests.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-cpows-in-tests.js
new file mode 100644
index 000000000..415cb2fc9
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-cpows-in-tests.js
@@ -0,0 +1,112 @@
+/**
+ * @fileoverview Prevent access to CPOWs in browser mochitests.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+var helpers = require("../helpers");
+
+var cpows = [
+  /^gBrowser\.contentWindow/,
+  /^gBrowser\.contentDocument/,
+  /^gBrowser\.selectedBrowser.contentWindow/,
+  /^browser\.contentDocument/,
+  /^window\.content/
+];
+
+var isInContentTask = false;
+
+module.exports = function(context) {
+  // ---------------------------------------------------------------------------
+  // Helpers
+  // ---------------------------------------------------------------------------
+
+  function showError(node, identifier) {
+    if (isInContentTask) {
+      return;
+    }
+
+    context.report({
+      node: node,
+      message: identifier +
+               " is a possible Cross Process Object Wrapper (CPOW)."
+    });
+  }
+
+  function isContentTask(node) {
+    return node &&
+           node.type === "MemberExpression" &&
+           node.property.type === "Identifier" &&
+           node.property.name === "spawn" &&
+           node.object.type === "Identifier" &&
+           node.object.name === "ContentTask";
+  }
+
+  // ---------------------------------------------------------------------------
+  // Public
+  // ---------------------------------------------------------------------------
+
+  return {
+    CallExpression: function(node) {
+      if (isContentTask(node.callee)) {
+        isInContentTask = true;
+      }
+    },
+
+    "CallExpression:exit": function(node) {
+      if (isContentTask(node.callee)) {
+        isInContentTask = false;
+      }
+    },
+
+    MemberExpression: function(node) {
+      if (helpers.getTestType(this) != "browser") {
+        return;
+      }
+
+      var expression = context.getSource(node);
+
+      // Only report a single CPOW error per node -- so if checking
+      // |cpows| reports one, don't report another below.
+      var someCpowFound = cpows.some(function(cpow) {
+        if (cpow.test(expression)) {
+          showError(node, expression);
+          return true;
+        }
+        return false;
+      });
+      if (!someCpowFound && helpers.getIsGlobalScope(context.getAncestors())) {
+        if (/^content\./.test(expression)) {
+          showError(node, expression);
+          return;
+        }
+      }
+    },
+
+    Identifier: function(node) {
+      if (helpers.getTestType(this) != "browser") {
+        return;
+      }
+
+      var expression = context.getSource(node);
+      if (expression == "content" || /^content\./.test(expression)) {
+        if (node.parent.type === "MemberExpression" &&
+            node.parent.object &&
+            node.parent.object.type === "Identifier" &&
+            node.parent.object.name != "content") {
+          return;
+        }
+        showError(node, expression);
+        return;
+      }
+    }
+  };
+};
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-single-arg-cu-import.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-single-arg-cu-import.js
new file mode 100644
index 000000000..b295f3555
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-single-arg-cu-import.js
@@ -0,0 +1,39 @@
+/**
+ * @fileoverview Reject use of single argument Cu.import
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+var helpers = require("../helpers");
+
+module.exports = function(context) {
+
+  // ---------------------------------------------------------------------------
+  // Public
+  //  --------------------------------------------------------------------------
+
+  return {
+    "CallExpression": function(node) {
+      if (node.callee.type === "MemberExpression") {
+        let memexp = node.callee;
+        if (memexp.object.type === "Identifier" &&
+            // Only Cu, not Components.utils; see bug 1230369.
+            memexp.object.name === "Cu" &&
+            memexp.property.type === "Identifier" &&
+            memexp.property.name === "import" &&
+            node.arguments.length === 1) {
+          context.report(node, "Single argument Cu.import exposes new " +
+                               "globals to all modules");
+        }
+      }
+    }
+  };
+};
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/reject-importGlobalProperties.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/reject-importGlobalProperties.js
new file mode 100644
index 000000000..0661c91d4
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/reject-importGlobalProperties.js
@@ -0,0 +1,37 @@
+/**
+ * @fileoverview Reject use of Cu.importGlobalProperties
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+var helpers = require("../helpers");
+
+module.exports = function(context) {
+
+  // ---------------------------------------------------------------------------
+  // Public
+  //  --------------------------------------------------------------------------
+
+  return {
+    "CallExpression": function(node) {
+      if (node.callee.type === "MemberExpression") {
+        let memexp = node.callee;
+        if (memexp.object.type === "Identifier" &&
+            // Only Cu, not Components.utils; see bug 1230369.
+            memexp.object.name === "Cu" &&
+            memexp.property.type === "Identifier" &&
+            memexp.property.name === "importGlobalProperties") {
+          context.report(node, "Unexpected call to Cu.importGlobalProperties");
+        }
+      }
+    }
+  };
+};
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/reject-some-requires.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/reject-some-requires.js
new file mode 100644
index 000000000..746f98a1f
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/reject-some-requires.js
@@ -0,0 +1,48 @@
+/**
+ * @fileoverview Reject some uses of require.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+module.exports = function(context) {
+
+  // ---------------------------------------------------------------------------
+  // Public
+  //  --------------------------------------------------------------------------
+
+  if (typeof(context.options[0]) !== "string") {
+    throw new Error("reject-some-requires expects a regexp");
+  }
+  const RX = new RegExp(context.options[0]);
+
+  const checkPath = function(node, path) {
+    if (RX.test(path)) {
+      context.report(node, `require(${path}) is not allowed`);
+    }
+  };
+
+  return {
+    "CallExpression": function(node) {
+      if (node.callee.type == "Identifier" &&
+          node.callee.name == "require" &&
+          node.arguments.length == 1 &&
+          node.arguments[0].type == "Literal") {
+        checkPath(node, node.arguments[0].value);
+      } else if (node.callee.type == "MemberExpression" &&
+                 node.callee.property.type == "Identifier" &&
+                 node.callee.property.name == "lazyRequireGetter" &&
+                 node.arguments.length >= 3 &&
+                 node.arguments[2].type == "Literal") {
+        checkPath(node, node.arguments[2].value);
+      }
+    }
+  };
+};
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/var-only-at-top-level.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/var-only-at-top-level.js
new file mode 100644
index 000000000..a1e14e166
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/var-only-at-top-level.js
@@ -0,0 +1,34 @@
+/**
+ * @fileoverview Marks all var declarations that are not at the top level
+ *               invalid.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+var helpers = require("../helpers");
+
+module.exports = function(context) {
+  // ---------------------------------------------------------------------------
+  // Public
+  //  --------------------------------------------------------------------------
+
+  return {
+    "VariableDeclaration": function(node) {
+      if (node.kind === "var") {
+        if (helpers.getIsGlobalScope(context.getAncestors())) {
+          return;
+        }
+
+        context.report(node, "Unexpected var, use let or const instead.");
+      }
+    }
+  };
+};