From 7927aa2e189453b9fddd6f30d05722774626102f Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Sat, 21 Feb 2015 13:06:02 +1100
Subject: [PATCH] make use strict directive stateless - fixes #828

---
 .../transformation/helpers/use-strict.js      | 21 -------------
 lib/babel/transformation/modules/system.js    |  7 +----
 .../transformers/internal/block-hoist.js      | 23 ++++++--------
 .../transformers/internal/declarations.js     | 31 +++++++++----------
 .../transformers/internal/module-formatter.js |  6 +---
 .../transformers/other/use-strict.js          | 18 +++++++----
 .../exports-default/expected.js               |  6 ++--
 .../es6-modules-amd/exports-from/expected.js  |  4 +--
 .../es6-modules-amd/exports-named/expected.js |  4 +--
 .../exports-variable/expected.js              |  6 ++--
 .../get-module-name-option/expected.js        |  6 ++--
 .../hoist-function-exports/expected.js        |  4 +--
 .../imports-default/expected.js               |  4 +--
 .../es6-modules-amd/imports-glob/expected.js  |  4 +--
 .../imports-mixing/expected.js                |  4 +--
 .../es6-modules-amd/imports-named/expected.js |  6 ++--
 .../es6-modules-amd/imports/expected.js       |  6 ++--
 .../es6-modules-amd/module-name/expected.js   |  4 +--
 .../es6-modules-amd/overview/expected.js      |  4 +--
 .../es6-modules-amd/remap/expected.js         |  4 +--
 .../exports-default/expected.js               |  6 ++--
 .../exports-from/expected.js                  |  6 ++--
 .../exports-generator/expected.js             |  6 ++--
 .../exports-named/expected.js                 |  6 ++--
 .../exports-variable/expected.js              |  6 ++--
 .../get-module-name-option/expected.js        |  6 ++--
 .../hoist-function-exports/expected.js        |  6 ++--
 .../imports-default/expected.js               |  6 ++--
 .../imports-glob/expected.js                  |  4 +--
 .../imports-mixing/expected.js                |  4 +--
 .../imports-named/expected.js                 |  6 ++--
 .../es6-modules-system/imports/expected.js    |  4 +--
 .../es6-modules-system/overview/expected.js   |  6 ++--
 .../es6-modules-system/remap/expected.js      |  6 ++--
 .../exports-default/expected.js               |  6 ++--
 .../es6-modules-umd/exports-from/expected.js  |  4 +--
 .../es6-modules-umd/exports-named/expected.js |  4 +--
 .../exports-variable/expected.js              |  6 ++--
 .../get-module-name-option/expected.js        |  6 ++--
 .../hoist-function-exports/expected.js        |  4 +--
 .../imports-default/expected.js               |  4 +--
 .../es6-modules-umd/imports-glob/expected.js  |  4 +--
 .../imports-mixing/expected.js                |  4 +--
 .../es6-modules-umd/imports-named/expected.js |  6 ++--
 .../es6-modules-umd/imports/expected.js       |  6 ++--
 .../es6-modules-umd/module-name/expected.js   |  4 +--
 .../es6-modules-umd/overview/expected.js      |  6 ++--
 .../es6-modules-umd/remap/expected.js         |  4 +--
 .../self-contained/modules-amd/expected.js    |  6 ++--
 .../self-contained/modules-system/expected.js |  6 ++--
 .../self-contained/modules-umd/expected.js    |  4 +--
 51 files changed, 152 insertions(+), 182 deletions(-)
 delete mode 100644 lib/babel/transformation/helpers/use-strict.js

diff --git a/lib/babel/transformation/helpers/use-strict.js b/lib/babel/transformation/helpers/use-strict.js
deleted file mode 100644
index 7709528a41..0000000000
--- a/lib/babel/transformation/helpers/use-strict.js
+++ /dev/null
@@ -1,21 +0,0 @@
-"use strict";
-
-var t = require("../../types");
-
-exports.has = function (node) {
-  var first = node.body[0];
-  return t.isExpressionStatement(first) && t.isLiteral(first.expression, { value: "use strict" });
-};
-
-exports.wrap = function (node, callback) {
-  var useStrictNode;
-  if (exports.has(node)) {
-    useStrictNode = node.body.shift();
-  }
-
-  callback();
-
-  if (useStrictNode) {
-    node.body.unshift(useStrictNode);
-  }
-};
diff --git a/lib/babel/transformation/modules/system.js b/lib/babel/transformation/modules/system.js
index 192fff7799..38ceec3799 100644
--- a/lib/babel/transformation/modules/system.js
+++ b/lib/babel/transformation/modules/system.js
@@ -4,12 +4,11 @@ module.exports = SystemFormatter;
 
 var DefaultFormatter = require("./_default");
 var AMDFormatter     = require("./amd");
-var useStrict        = require("../helpers/use-strict");
 var util             = require("../../util");
-var t                = require("../../types");
 var last             = require("lodash/array/last");
 var each             = require("lodash/collection/each");
 var map              = require("lodash/collection/map");
+var t                = require("../../types");
 
 function SystemFormatter(file) {
   this.exportIdentifier = file.scope.generateUidIdentifier("export");
@@ -193,9 +192,5 @@ SystemFormatter.prototype.transform = function (program) {
 
   handlerBody.push(returnStatement);
 
-  if (useStrict.has(block)) {
-    handlerBody.unshift(block.body.shift());
-  }
-
   program.body = [runner];
 };
diff --git a/lib/babel/transformation/transformers/internal/block-hoist.js b/lib/babel/transformation/transformers/internal/block-hoist.js
index d8936adca8..95d13967d7 100644
--- a/lib/babel/transformation/transformers/internal/block-hoist.js
+++ b/lib/babel/transformation/transformers/internal/block-hoist.js
@@ -1,9 +1,8 @@
 "use strict";
 
-var useStrict = require("../../helpers/use-strict");
-var groupBy   = require("lodash/collection/groupBy");
-var flatten   = require("lodash/array/flatten");
-var values    = require("lodash/object/values");
+var groupBy = require("lodash/collection/groupBy");
+var flatten = require("lodash/array/flatten");
+var values  = require("lodash/object/values");
 
 // Priority:
 //
@@ -22,15 +21,13 @@ exports.Program = {
     }
     if (!hasChange) return;
 
-    useStrict.wrap(node, function () {
-      var nodePriorities = groupBy(node.body, function (bodyNode) {
-        var priority = bodyNode._blockHoist;
-        if (priority == null) priority = 1;
-        if (priority === true) priority = 2;
-        return priority;
-      });
-
-      node.body = flatten(values(nodePriorities).reverse());
+    var nodePriorities = groupBy(node.body, function (bodyNode) {
+      var priority = bodyNode._blockHoist;
+      if (priority == null) priority = 1;
+      if (priority === true) priority = 2;
+      return priority;
     });
+
+    node.body = flatten(values(nodePriorities).reverse());
   }
 };
diff --git a/lib/babel/transformation/transformers/internal/declarations.js b/lib/babel/transformation/transformers/internal/declarations.js
index cd07030b56..a4297143a4 100644
--- a/lib/babel/transformation/transformers/internal/declarations.js
+++ b/lib/babel/transformation/transformers/internal/declarations.js
@@ -1,7 +1,6 @@
 "use strict";
 
-var useStrict = require("../../helpers/use-strict");
-var t         = require("../../../types");
+var t = require("../../../types");
 
 exports.secondPass = true;
 
@@ -12,25 +11,23 @@ exports.Program = function (node, parent, scope, file) {
   var kinds = {};
   var kind;
 
-  useStrict.wrap(node, function () {
-    for (var i in node._declarations) {
-      var declar = node._declarations[i];
+  for (var i in node._declarations) {
+    var declar = node._declarations[i];
 
-      kind = declar.kind || "var";
-      var declarNode = t.variableDeclarator(declar.id, declar.init);
+    kind = declar.kind || "var";
+    var declarNode = t.variableDeclarator(declar.id, declar.init);
 
-      if (declar.init) {
-        node.body.unshift(file.attachAuxiliaryComment(t.variableDeclaration(kind, [declarNode])));
-      } else {
-        kinds[kind] = kinds[kind] || [];
-        kinds[kind].push(declarNode);
-      }
+    if (declar.init) {
+      node.body.unshift(file.attachAuxiliaryComment(t.variableDeclaration(kind, [declarNode])));
+    } else {
+      kinds[kind] = kinds[kind] || [];
+      kinds[kind].push(declarNode);
     }
+  }
 
-    for (kind in kinds) {
-      node.body.unshift(file.attachAuxiliaryComment(t.variableDeclaration(kind, kinds[kind])));
-    }
-  });
+  for (kind in kinds) {
+    node.body.unshift(file.attachAuxiliaryComment(t.variableDeclaration(kind, kinds[kind])));
+  }
 
   node._declarations = null;
 };
diff --git a/lib/babel/transformation/transformers/internal/module-formatter.js b/lib/babel/transformation/transformers/internal/module-formatter.js
index d1982280c4..4499ea7bbb 100644
--- a/lib/babel/transformation/transformers/internal/module-formatter.js
+++ b/lib/babel/transformation/transformers/internal/module-formatter.js
@@ -1,13 +1,9 @@
 "use strict";
 
-var useStrict = require("../../helpers/use-strict");
-
 exports.Program = function (program, parent, scope, file) {
   if (!file.transformers["es6.modules"].canRun()) return;
 
-  useStrict.wrap(program, function () {
-    program.body = file.dynamicImports.concat(program.body);
-  });
+  program.body = file.dynamicImports.concat(program.body);
 
   if (file.moduleFormatter.transform) {
     file.moduleFormatter.transform(program);
diff --git a/lib/babel/transformation/transformers/other/use-strict.js b/lib/babel/transformation/transformers/other/use-strict.js
index 947bcca27e..7420db08ae 100644
--- a/lib/babel/transformation/transformers/other/use-strict.js
+++ b/lib/babel/transformation/transformers/other/use-strict.js
@@ -1,15 +1,21 @@
 "use strict";
 
-var useStrict = require("../../helpers/use-strict");
-var messages  = require("../../../messages");
-var t         = require("../../../types");
+var messages = require("../../../messages");
+var t        = require("../../../types");
 
-exports.Program = function (program) {
-  if (!useStrict.has(program)) {
-    program.body.unshift(t.expressionStatement(t.literal("use strict")));
+exports.Program = {
+  enter: function (program, parent, scope, file) {
+    var first = program.body[0];
+    if (t.isExpressionStatement(first) && t.isLiteral(first.expression, { value: "use strict" })) {
+      program.body.shift();
+    }
   }
 };
 
+exports.post = function (file) {
+  file.ast.program.body.unshift(t.expressionStatement(t.literal("use strict")));
+};
+
 exports.FunctionDeclaration =
 exports.FunctionExpression = function () {
   this.skip();
diff --git a/test/fixtures/transformation/es6-modules-amd/exports-default/expected.js b/test/fixtures/transformation/es6-modules-amd/exports-default/expected.js
index 2c5794f860..371d42a3ac 100644
--- a/test/fixtures/transformation/es6-modules-amd/exports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/exports-default/expected.js
@@ -1,6 +1,6 @@
-define(["exports", "module"], function (exports, module) {
-  "use strict";
+"use strict";
 
+define(["exports", "module"], function (exports, module) {
   var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
 
   module.exports = foo;
@@ -23,4 +23,4 @@ define(["exports", "module"], function (exports, module) {
   };
 
   module.exports = Foo;
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-amd/exports-from/expected.js b/test/fixtures/transformation/es6-modules-amd/exports-from/expected.js
index 113dd40be3..ed602a6536 100644
--- a/test/fixtures/transformation/es6-modules-amd/exports-from/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/exports-from/expected.js
@@ -1,6 +1,6 @@
-define(["exports", "foo"], function (exports, _foo) {
-  "use strict";
+"use strict";
 
+define(["exports", "foo"], function (exports, _foo) {
   var _interopRequireWildcard = function (obj) { return obj && obj.__esModule ? obj : { "default": obj }; };
 
   var _defaults = function (obj, defaults) { var keys = Object.getOwnPropertyNames(defaults); for (var i = 0; i < keys.length; i++) { var key = keys[i]; var value = Object.getOwnPropertyDescriptor(defaults, key); if (value && value.configurable && obj[key] === undefined) { Object.defineProperty(obj, key, value); } } return obj; };
diff --git a/test/fixtures/transformation/es6-modules-amd/exports-named/expected.js b/test/fixtures/transformation/es6-modules-amd/exports-named/expected.js
index d66e609acb..84d448ff9c 100644
--- a/test/fixtures/transformation/es6-modules-amd/exports-named/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/exports-named/expected.js
@@ -1,6 +1,6 @@
-define(["exports"], function (exports) {
-  "use strict";
+"use strict";
 
+define(["exports"], function (exports) {
   exports.foo = foo;
   exports.foo = foo;
   exports.bar = bar;
diff --git a/test/fixtures/transformation/es6-modules-amd/exports-variable/expected.js b/test/fixtures/transformation/es6-modules-amd/exports-variable/expected.js
index e0b5ef829f..78d201535b 100644
--- a/test/fixtures/transformation/es6-modules-amd/exports-variable/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/exports-variable/expected.js
@@ -1,6 +1,6 @@
-define(["exports"], function (exports) {
-  "use strict";
+"use strict";
 
+define(["exports"], function (exports) {
   var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
 
   exports.foo7 = foo7;
@@ -21,4 +21,4 @@ define(["exports"], function (exports) {
   Object.defineProperty(exports, "__esModule", {
     value: true
   });
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-amd/get-module-name-option/expected.js b/test/fixtures/transformation/es6-modules-amd/get-module-name-option/expected.js
index f0e566fff4..b06fd3928a 100644
--- a/test/fixtures/transformation/es6-modules-amd/get-module-name-option/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/get-module-name-option/expected.js
@@ -1,3 +1,3 @@
-define("my custom module name", ["exports"], function (exports) {
-  "use strict";
-});
+"use strict";
+
+define("my custom module name", ["exports"], function (exports) {});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-amd/hoist-function-exports/expected.js b/test/fixtures/transformation/es6-modules-amd/hoist-function-exports/expected.js
index 79267d3f30..058d009ac2 100644
--- a/test/fixtures/transformation/es6-modules-amd/hoist-function-exports/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/hoist-function-exports/expected.js
@@ -1,6 +1,6 @@
-define(["exports", "./evens"], function (exports, _evens) {
-  "use strict";
+"use strict";
 
+define(["exports", "./evens"], function (exports, _evens) {
   exports.nextOdd = nextOdd;
   var isEven = _evens.isEven;
   function nextOdd(n) {
diff --git a/test/fixtures/transformation/es6-modules-amd/imports-default/expected.js b/test/fixtures/transformation/es6-modules-amd/imports-default/expected.js
index 4575943441..167222ee75 100644
--- a/test/fixtures/transformation/es6-modules-amd/imports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/imports-default/expected.js
@@ -1,6 +1,6 @@
-define(["exports", "foo"], function (exports, _foo) {
-  "use strict";
+"use strict";
 
+define(["exports", "foo"], function (exports, _foo) {
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-amd/imports-glob/expected.js b/test/fixtures/transformation/es6-modules-amd/imports-glob/expected.js
index cc03946787..4788c80508 100644
--- a/test/fixtures/transformation/es6-modules-amd/imports-glob/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/imports-glob/expected.js
@@ -1,5 +1,5 @@
-define(["exports", "foo"], function (exports, _foo) {
-  "use strict";
+"use strict";
 
+define(["exports", "foo"], function (exports, _foo) {
   var foo = _foo;
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-amd/imports-mixing/expected.js b/test/fixtures/transformation/es6-modules-amd/imports-mixing/expected.js
index b147224a07..59164e1d1f 100644
--- a/test/fixtures/transformation/es6-modules-amd/imports-mixing/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/imports-mixing/expected.js
@@ -1,6 +1,6 @@
-define(["exports", "foo"], function (exports, _foo) {
-  "use strict";
+"use strict";
 
+define(["exports", "foo"], function (exports, _foo) {
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-amd/imports-named/expected.js b/test/fixtures/transformation/es6-modules-amd/imports-named/expected.js
index f1cbf26ee3..8e5e4a9e81 100644
--- a/test/fixtures/transformation/es6-modules-amd/imports-named/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/imports-named/expected.js
@@ -1,10 +1,10 @@
-define(["exports", "foo"], function (exports, _foo) {
-  "use strict";
+"use strict";
 
+define(["exports", "foo"], function (exports, _foo) {
   var bar = _foo.bar;
   var bar2 = _foo.bar2;
   var baz = _foo.baz;
   var baz2 = _foo.bar;
   var baz3 = _foo.bar;
   var xyz = _foo.xyz;
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-amd/imports/expected.js b/test/fixtures/transformation/es6-modules-amd/imports/expected.js
index 84e1e6dcc7..36ff98ebcc 100644
--- a/test/fixtures/transformation/es6-modules-amd/imports/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/imports/expected.js
@@ -1,3 +1,3 @@
-define(["exports", "foo", "foo-bar", "./directory/foo-bar"], function (exports, _foo, _fooBar, _directoryFooBar) {
-  "use strict";
-});
\ No newline at end of file
+"use strict";
+
+define(["exports", "foo", "foo-bar", "./directory/foo-bar"], function (exports, _foo, _fooBar, _directoryFooBar) {});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-amd/module-name/expected.js b/test/fixtures/transformation/es6-modules-amd/module-name/expected.js
index c129a9ffb6..5c6619dc82 100644
--- a/test/fixtures/transformation/es6-modules-amd/module-name/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/module-name/expected.js
@@ -1,5 +1,5 @@
-define("es6-modules-amd/module-name/expected", ["exports"], function (exports) {
-  "use strict";
+"use strict";
 
+define("es6-modules-amd/module-name/expected", ["exports"], function (exports) {
   foobar();
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-amd/overview/expected.js b/test/fixtures/transformation/es6-modules-amd/overview/expected.js
index a9993c1612..28fa5347fa 100644
--- a/test/fixtures/transformation/es6-modules-amd/overview/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/overview/expected.js
@@ -1,6 +1,6 @@
-define(["exports", "foo", "foo-bar", "./directory/foo-bar"], function (exports, _foo, _fooBar, _directoryFooBar) {
-  "use strict";
+"use strict";
 
+define(["exports", "foo", "foo-bar", "./directory/foo-bar"], function (exports, _foo, _fooBar, _directoryFooBar) {
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-amd/remap/expected.js b/test/fixtures/transformation/es6-modules-amd/remap/expected.js
index accde1fb6e..0fe9ee14d8 100644
--- a/test/fixtures/transformation/es6-modules-amd/remap/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/remap/expected.js
@@ -1,6 +1,6 @@
-define(["exports"], function (exports) {
-  "use strict";
+"use strict";
 
+define(["exports"], function (exports) {
   var test = exports.test = 2;
   test = exports.test = 5;
   test = exports.test += 1;
diff --git a/test/fixtures/transformation/es6-modules-system/exports-default/expected.js b/test/fixtures/transformation/es6-modules-system/exports-default/expected.js
index 93fa08a649..9fa1b7604a 100644
--- a/test/fixtures/transformation/es6-modules-system/exports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/exports-default/expected.js
@@ -1,6 +1,6 @@
-System.register([], function (_export) {
-  "use strict";
+"use strict";
 
+System.register([], function (_export) {
   var _classCallCheck, _default, Foo;
 
   _export("default", foo);
@@ -34,4 +34,4 @@ System.register([], function (_export) {
       _export("default", Foo);
     }
   };
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/exports-from/expected.js b/test/fixtures/transformation/es6-modules-system/exports-from/expected.js
index b7b8242360..389dfc41ae 100644
--- a/test/fixtures/transformation/es6-modules-system/exports-from/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/exports-from/expected.js
@@ -1,6 +1,6 @@
-System.register(["foo"], function (_export) {
-  "use strict";
+"use strict";
 
+System.register(["foo"], function (_export) {
   return {
     setters: [function (_foo) {
       for (var _key in _foo) {
@@ -23,4 +23,4 @@ System.register(["foo"], function (_export) {
     }],
     execute: function () {}
   };
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/exports-generator/expected.js b/test/fixtures/transformation/es6-modules-system/exports-generator/expected.js
index ea08012703..b7ae39a4d7 100644
--- a/test/fixtures/transformation/es6-modules-system/exports-generator/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/exports-generator/expected.js
@@ -1,6 +1,6 @@
-System.register([], function (_export) {
-  "use strict";
+"use strict";
 
+System.register([], function (_export) {
   var generator = regeneratorRuntime.mark(function generator() {
     return regeneratorRuntime.wrap(function generator$(context$1$0) {
       while (1) switch (context$1$0.prev = context$1$0.next) {
@@ -21,4 +21,4 @@ System.register([], function (_export) {
     setters: [],
     execute: function () {}
   };
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/exports-named/expected.js b/test/fixtures/transformation/es6-modules-system/exports-named/expected.js
index 86487ee2f5..e332163eba 100644
--- a/test/fixtures/transformation/es6-modules-system/exports-named/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/exports-named/expected.js
@@ -1,6 +1,6 @@
-System.register([], function (_export) {
-  "use strict";
+"use strict";
 
+System.register([], function (_export) {
   return {
     setters: [],
     execute: function () {
@@ -19,4 +19,4 @@ System.register([], function (_export) {
       _export("bar", bar);
     }
   };
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/exports-variable/expected.js b/test/fixtures/transformation/es6-modules-system/exports-variable/expected.js
index 2b6c6efd54..9ada1fff32 100644
--- a/test/fixtures/transformation/es6-modules-system/exports-variable/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/exports-variable/expected.js
@@ -1,6 +1,6 @@
-System.register([], function (_export) {
-  "use strict";
+"use strict";
 
+System.register([], function (_export) {
   var _classCallCheck, foo, foo2, foo3, foo4, foo5, foo6, foo8;
 
   _export("foo7", foo7);
@@ -24,4 +24,4 @@ System.register([], function (_export) {
       _export("foo3", foo3 = 5);
     }
   };
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/get-module-name-option/expected.js b/test/fixtures/transformation/es6-modules-system/get-module-name-option/expected.js
index 0def1f9524..bd650c0abc 100644
--- a/test/fixtures/transformation/es6-modules-system/get-module-name-option/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/get-module-name-option/expected.js
@@ -1,8 +1,8 @@
-System.register("my custom module name", [], function (_export) {
-  "use strict";
+"use strict";
 
+System.register("my custom module name", [], function (_export) {
   return {
     setters: [],
     execute: function () {}
   };
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/hoist-function-exports/expected.js b/test/fixtures/transformation/es6-modules-system/hoist-function-exports/expected.js
index 609ee753d4..553b69fe58 100644
--- a/test/fixtures/transformation/es6-modules-system/hoist-function-exports/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/hoist-function-exports/expected.js
@@ -1,6 +1,6 @@
-System.register(["./evens"], function (_export) {
-  "use strict";
+"use strict";
 
+System.register(["./evens"], function (_export) {
   var isEven, p, isOdd;
 
   _export("nextOdd", nextOdd);
@@ -22,4 +22,4 @@ System.register(["./evens"], function (_export) {
       })(isEven));
     }
   };
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/imports-default/expected.js b/test/fixtures/transformation/es6-modules-system/imports-default/expected.js
index 16a71b2ed4..12696f6653 100644
--- a/test/fixtures/transformation/es6-modules-system/imports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/imports-default/expected.js
@@ -1,6 +1,6 @@
-System.register(["foo"], function (_export) {
-  "use strict";
+"use strict";
 
+System.register(["foo"], function (_export) {
   var foo, foo2;
   return {
     setters: [function (_foo) {
@@ -9,4 +9,4 @@ System.register(["foo"], function (_export) {
     }],
     execute: function () {}
   };
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/imports-glob/expected.js b/test/fixtures/transformation/es6-modules-system/imports-glob/expected.js
index 6e08c8dcc9..acd0e1efcf 100644
--- a/test/fixtures/transformation/es6-modules-system/imports-glob/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/imports-glob/expected.js
@@ -1,6 +1,6 @@
-System.register(["foo"], function (_export) {
-  "use strict";
+"use strict";
 
+System.register(["foo"], function (_export) {
   var foo;
   return {
     setters: [function (_foo) {
diff --git a/test/fixtures/transformation/es6-modules-system/imports-mixing/expected.js b/test/fixtures/transformation/es6-modules-system/imports-mixing/expected.js
index 31b6f179ea..7e4f71269d 100644
--- a/test/fixtures/transformation/es6-modules-system/imports-mixing/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/imports-mixing/expected.js
@@ -1,6 +1,6 @@
-System.register(["foo"], function (_export) {
-  "use strict";
+"use strict";
 
+System.register(["foo"], function (_export) {
   var foo, xyz;
   return {
     setters: [function (_foo) {
diff --git a/test/fixtures/transformation/es6-modules-system/imports-named/expected.js b/test/fixtures/transformation/es6-modules-system/imports-named/expected.js
index e6704667be..9b8eb605bf 100644
--- a/test/fixtures/transformation/es6-modules-system/imports-named/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/imports-named/expected.js
@@ -1,6 +1,6 @@
-System.register(["foo"], function (_export) {
-  "use strict";
+"use strict";
 
+System.register(["foo"], function (_export) {
   var bar, bar2, baz, baz2, baz3, xyz;
   return {
     setters: [function (_foo) {
@@ -13,4 +13,4 @@ System.register(["foo"], function (_export) {
     }],
     execute: function () {}
   };
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/imports/expected.js b/test/fixtures/transformation/es6-modules-system/imports/expected.js
index 595df89e93..dcd2757e57 100644
--- a/test/fixtures/transformation/es6-modules-system/imports/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/imports/expected.js
@@ -1,6 +1,6 @@
-System.register(["foo", "foo-bar", "./directory/foo-bar"], function (_export) {
-  "use strict";
+"use strict";
 
+System.register(["foo", "foo-bar", "./directory/foo-bar"], function (_export) {
   return {
     setters: [function (_foo) {}, function (_fooBar) {}, function (_directoryFooBar) {}],
     execute: function () {}
diff --git a/test/fixtures/transformation/es6-modules-system/overview/expected.js b/test/fixtures/transformation/es6-modules-system/overview/expected.js
index 1114e6a2da..d7a161df9f 100644
--- a/test/fixtures/transformation/es6-modules-system/overview/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/overview/expected.js
@@ -1,6 +1,6 @@
-System.register(["foo", "foo-bar", "./directory/foo-bar"], function (_export) {
-  "use strict";
+"use strict";
 
+System.register(["foo", "foo-bar", "./directory/foo-bar"], function (_export) {
   var foo, foo2, bar, bar2, test2;
   return {
     setters: [function (_foo) {
@@ -17,4 +17,4 @@ System.register(["foo", "foo-bar", "./directory/foo-bar"], function (_export) {
       _export("default", test);
     }
   };
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/remap/expected.js b/test/fixtures/transformation/es6-modules-system/remap/expected.js
index fa88c07f53..75dfba18e2 100644
--- a/test/fixtures/transformation/es6-modules-system/remap/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/remap/expected.js
@@ -1,6 +1,6 @@
-System.register([], function (_export) {
-  "use strict";
+"use strict";
 
+System.register([], function (_export) {
   var test;
   return {
     setters: [],
@@ -17,4 +17,4 @@ System.register([], function (_export) {
       })();
     }
   };
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/exports-default/expected.js b/test/fixtures/transformation/es6-modules-umd/exports-default/expected.js
index 287f0ec11d..dea3d841ba 100644
--- a/test/fixtures/transformation/es6-modules-umd/exports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/exports-default/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "module"], factory);
@@ -5,8 +7,6 @@
     factory(exports, module);
   }
 })(function (exports, module) {
-  "use strict";
-
   var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
 
   module.exports = foo;
@@ -29,4 +29,4 @@
   };
 
   module.exports = Foo;
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/exports-from/expected.js b/test/fixtures/transformation/es6-modules-umd/exports-from/expected.js
index 35cdb100e3..022983fc7b 100644
--- a/test/fixtures/transformation/es6-modules-umd/exports-from/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/exports-from/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo"], factory);
@@ -5,8 +7,6 @@
     factory(exports, require("foo"));
   }
 })(function (exports, _foo) {
-  "use strict";
-
   var _interopRequireWildcard = function (obj) { return obj && obj.__esModule ? obj : { "default": obj }; };
 
   var _defaults = function (obj, defaults) { var keys = Object.getOwnPropertyNames(defaults); for (var i = 0; i < keys.length; i++) { var key = keys[i]; var value = Object.getOwnPropertyDescriptor(defaults, key); if (value && value.configurable && obj[key] === undefined) { Object.defineProperty(obj, key, value); } } return obj; };
diff --git a/test/fixtures/transformation/es6-modules-umd/exports-named/expected.js b/test/fixtures/transformation/es6-modules-umd/exports-named/expected.js
index 3b4d067ec0..a894d9a509 100644
--- a/test/fixtures/transformation/es6-modules-umd/exports-named/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/exports-named/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports"], factory);
@@ -5,8 +7,6 @@
     factory(exports);
   }
 })(function (exports) {
-  "use strict";
-
   exports.foo = foo;
   exports.foo = foo;
   exports.bar = bar;
diff --git a/test/fixtures/transformation/es6-modules-umd/exports-variable/expected.js b/test/fixtures/transformation/es6-modules-umd/exports-variable/expected.js
index 97a29f5fb3..828ae59ea0 100644
--- a/test/fixtures/transformation/es6-modules-umd/exports-variable/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/exports-variable/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports"], factory);
@@ -5,8 +7,6 @@
     factory(exports);
   }
 })(function (exports) {
-  "use strict";
-
   var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
 
   exports.foo7 = foo7;
@@ -27,4 +27,4 @@
   Object.defineProperty(exports, "__esModule", {
     value: true
   });
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/get-module-name-option/expected.js b/test/fixtures/transformation/es6-modules-umd/get-module-name-option/expected.js
index db14ef8bc3..bd0e644592 100644
--- a/test/fixtures/transformation/es6-modules-umd/get-module-name-option/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/get-module-name-option/expected.js
@@ -1,9 +1,9 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define("my custom module name", ["exports"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports);
   }
-})(function (exports) {
-  "use strict";
-});
+})(function (exports) {});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/hoist-function-exports/expected.js b/test/fixtures/transformation/es6-modules-umd/hoist-function-exports/expected.js
index 1241f1f68e..09d47d6c27 100644
--- a/test/fixtures/transformation/es6-modules-umd/hoist-function-exports/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/hoist-function-exports/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "./evens"], factory);
@@ -5,8 +7,6 @@
     factory(exports, require("./evens"));
   }
 })(function (exports, _evens) {
-  "use strict";
-
   exports.nextOdd = nextOdd;
   var isEven = _evens.isEven;
   function nextOdd(n) {
diff --git a/test/fixtures/transformation/es6-modules-umd/imports-default/expected.js b/test/fixtures/transformation/es6-modules-umd/imports-default/expected.js
index 46111b877c..17c0bb534c 100644
--- a/test/fixtures/transformation/es6-modules-umd/imports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/imports-default/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo"], factory);
@@ -5,8 +7,6 @@
     factory(exports, require("foo"));
   }
 })(function (exports, _foo) {
-  "use strict";
-
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-umd/imports-glob/expected.js b/test/fixtures/transformation/es6-modules-umd/imports-glob/expected.js
index 45a763f2f2..067a1a2714 100644
--- a/test/fixtures/transformation/es6-modules-umd/imports-glob/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/imports-glob/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo"], factory);
@@ -5,7 +7,5 @@
     factory(exports, require("foo"));
   }
 })(function (exports, _foo) {
-  "use strict";
-
   var foo = _foo;
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/imports-mixing/expected.js b/test/fixtures/transformation/es6-modules-umd/imports-mixing/expected.js
index 6b684e31de..5de8931b9b 100644
--- a/test/fixtures/transformation/es6-modules-umd/imports-mixing/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/imports-mixing/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo"], factory);
@@ -5,8 +7,6 @@
     factory(exports, require("foo"));
   }
 })(function (exports, _foo) {
-  "use strict";
-
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-umd/imports-named/expected.js b/test/fixtures/transformation/es6-modules-umd/imports-named/expected.js
index d4c162c172..3e4f5746d9 100644
--- a/test/fixtures/transformation/es6-modules-umd/imports-named/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/imports-named/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo"], factory);
@@ -5,12 +7,10 @@
     factory(exports, require("foo"));
   }
 })(function (exports, _foo) {
-  "use strict";
-
   var bar = _foo.bar;
   var bar2 = _foo.bar2;
   var baz = _foo.baz;
   var baz2 = _foo.bar;
   var baz3 = _foo.bar;
   var xyz = _foo.xyz;
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/imports/expected.js b/test/fixtures/transformation/es6-modules-umd/imports/expected.js
index 2e39b15cd2..29cf8095a7 100644
--- a/test/fixtures/transformation/es6-modules-umd/imports/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/imports/expected.js
@@ -1,9 +1,9 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo", "foo-bar", "./directory/foo-bar"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports, require("foo"), require("foo-bar"), require("./directory/foo-bar"));
   }
-})(function (exports, _foo, _fooBar, _directoryFooBar) {
-  "use strict";
-});
\ No newline at end of file
+})(function (exports, _foo, _fooBar, _directoryFooBar) {});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/module-name/expected.js b/test/fixtures/transformation/es6-modules-umd/module-name/expected.js
index aa570b25e3..193a600c46 100644
--- a/test/fixtures/transformation/es6-modules-umd/module-name/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/module-name/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define("es6-modules-umd/module-name/expected", ["exports"], factory);
@@ -5,7 +7,5 @@
     factory(exports);
   }
 })(function (exports) {
-  "use strict";
-
   foobar();
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/overview/expected.js b/test/fixtures/transformation/es6-modules-umd/overview/expected.js
index 9d39fbaa49..821fab6755 100644
--- a/test/fixtures/transformation/es6-modules-umd/overview/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/overview/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo", "foo-bar", "./directory/foo-bar"], factory);
@@ -5,8 +7,6 @@
     factory(exports, require("foo"), require("foo-bar"), require("./directory/foo-bar"));
   }
 })(function (exports, _foo, _fooBar, _directoryFooBar) {
-  "use strict";
-
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
   var foo = _interopRequire(_foo);
@@ -21,4 +21,4 @@
   Object.defineProperty(exports, "__esModule", {
     value: true
   });
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/remap/expected.js b/test/fixtures/transformation/es6-modules-umd/remap/expected.js
index e44f8e70c5..82882dde3f 100644
--- a/test/fixtures/transformation/es6-modules-umd/remap/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/remap/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports"], factory);
@@ -5,8 +7,6 @@
     factory(exports);
   }
 })(function (exports) {
-  "use strict";
-
   var test = exports.test = 2;
   test = exports.test = 5;
   test = exports.test += 1;
diff --git a/test/fixtures/transformation/self-contained/modules-amd/expected.js b/test/fixtures/transformation/self-contained/modules-amd/expected.js
index 9543e99b18..9db3f81296 100644
--- a/test/fixtures/transformation/self-contained/modules-amd/expected.js
+++ b/test/fixtures/transformation/self-contained/modules-amd/expected.js
@@ -1,7 +1,7 @@
-define(["exports", "foo", "babel-runtime/helpers"], function (exports, _foo, _babelRuntimeHelpers) {
-  "use strict";
+"use strict";
 
+define(["exports", "foo", "babel-runtime/helpers"], function (exports, _foo, _babelRuntimeHelpers) {
   var _babelHelpers = _babelRuntimeHelpers["default"];
 
   var foo = _babelHelpers.interopRequire(_foo);
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/self-contained/modules-system/expected.js b/test/fixtures/transformation/self-contained/modules-system/expected.js
index 8bbdcb08a7..526b72c64d 100644
--- a/test/fixtures/transformation/self-contained/modules-system/expected.js
+++ b/test/fixtures/transformation/self-contained/modules-system/expected.js
@@ -1,6 +1,6 @@
-System.register(["babel-runtime/helpers"], function (_export) {
-  "use strict";
+"use strict";
 
+System.register(["babel-runtime/helpers"], function (_export) {
   var _babelHelpers;
 
   return {
@@ -11,4 +11,4 @@ System.register(["babel-runtime/helpers"], function (_export) {
       foo.apply(undefined, _babelHelpers.toConsumableArray(bar));
     }
   };
-});
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/self-contained/modules-umd/expected.js b/test/fixtures/transformation/self-contained/modules-umd/expected.js
index 9808628579..d380c97e69 100644
--- a/test/fixtures/transformation/self-contained/modules-umd/expected.js
+++ b/test/fixtures/transformation/self-contained/modules-umd/expected.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo", "babel-runtime/helpers"], factory);
@@ -5,8 +7,6 @@
     factory(exports, require("foo"), require("babel-runtime/helpers"));
   }
 })(function (exports, _foo, _babelRuntimeHelpers) {
-  "use strict";
-
   var _babelHelpers = _babelRuntimeHelpers["default"];
 
   var foo = _babelHelpers.interopRequire(_foo);