close iterators on abrupt completion - google/traceur-compiler#1773 #838

src/babel/transformation/templates/for-of.js

@@ -1,3 +1,21 @@
-for (var ITERATOR_KEY = OBJECT[Symbol.iterator](), STEP_KEY; !(STEP_KEY = ITERATOR_KEY.next()).done; ) {
+var ITERATOR_COMPLETION = true;
+var ITERATOR_HAD_ERROR_KEY = false;
+var ITERATOR_ERROR_KEY = undefined;
+try {
+  for (var ITERATOR_KEY = OBJECT[Symbol.iterator](), STEP_KEY; !(ITERATOR_COMPLETION = (STEP_KEY = ITERATOR_KEY.next()).done); ITERATOR_COMPLETION = true) {
 
+  }
+} catch (err) {
+  ITERATOR_HAD_ERROR_KEY = true;
+  ITERATOR_ERROR_KEY = err;
+} finally {
+  try {
+    if (!ITERATOR_COMPLETION && ITERATOR_KEY.return) {
+      ITERATOR_KEY.return();
+    }
+  } finally {
+    if (ITERATOR_HAD_ERROR_KEY) {
+      throw ITERATOR_ERROR_KEY;
+    }
+  }
 }

src/babel/transformation/transformers/es6/for-of.js

@@ -32,7 +32,7 @@ exports.ForOfStatement = function (node, parent, scope, file) {
   // todo: find out why this is necessary? #538
   loop._scopeInfo = node._scopeInfo;
 
-  return loop;
+  return build.node;
 };
 
 var breakVisitor = {
@@ -113,6 +113,7 @@ var loose = function (node, parent, scope, file) {
 
   return {
     declar: declar,
+    node:   loop,
     loop:   loop
   };
 };
@@ -140,12 +141,18 @@ var spec = function (node, parent, scope, file) {
 
   var iteratorKey = scope.generateUidIdentifier("iterator");
 
-  var loop = util.template("for-of", {
+  var node = util.template("for-of", {
+    ITERATOR_HAD_ERROR_KEY: scope.generateUidIdentifier("didIteratorError"),
+    ITERATOR_COMPLETION:    scope.generateUidIdentifier("iteratorNormalCompletion"),
+    ITERATOR_ERROR_KEY:     scope.generateUidIdentifier("iteratorError"),
     ITERATOR_KEY:           iteratorKey,
     STEP_KEY:               stepKey,
-    OBJECT:       node.right
+    OBJECT:                 node.right,
+    BODY:                   null
   });
 
+  var loop = node[3].block.body[0];
+
   //
 
   scope.traverse(node, breakVisitor, {
@@ -160,6 +167,7 @@ var spec = function (node, parent, scope, file) {
 
   return {
     declar: declar,
-    loop:   loop
+    loop:   loop,
+    node:   node
   };
 };

test/fixtures/transformation/es6-block-scoping/hoisting/expected.js

@@ -1,6 +1,11 @@
 "use strict";
 
-for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+var _iteratorNormalCompletion = true;
+var _didIteratorError = false;
+var _iteratorError = undefined;
+
+try {
+  for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
     var x;
 
     (function () {
@@ -11,4 +16,18 @@ for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_step = _iterator.ne
         return i * x;
       });
     })();
+  }
+} catch (err) {
+  _didIteratorError = true;
+  _iteratorError = err;
+} finally {
+  try {
+    if (!_iteratorNormalCompletion && _iterator["return"]) {
+      _iterator["return"]();
+    }
+  } finally {
+    if (_didIteratorError) {
+      throw _iteratorError;
+    }
+  }
 }

test/fixtures/transformation/es6-destructuring/for-of/expected.js

@@ -2,10 +2,29 @@
 
 var _slicedToArray = function (arr, i) { if (Array.isArray(arr)) { return arr; } else if (Symbol.iterator in Object(arr)) { var _arr = []; for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) { _arr.push(_step.value); if (i && _arr.length === i) break; } return _arr; } else { throw new TypeError("Invalid attempt to destructure non-iterable instance"); } };
 
-for (var _iterator = test.expectation.registers[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+var _iteratorNormalCompletion = true;
+var _didIteratorError = false;
+var _iteratorError = undefined;
+
+try {
+  for (var _iterator = test.expectation.registers[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
     var _step$value = _slicedToArray(_step.value, 3);
 
     var name = _step$value[0];
     var before = _step$value[1];
     var after = _step$value[2];
+  }
+} catch (err) {
+  _didIteratorError = true;
+  _iteratorError = err;
+} finally {
+  try {
+    if (!_iteratorNormalCompletion && _iterator["return"]) {
+      _iterator["return"]();
+    }
+  } finally {
+    if (_didIteratorError) {
+      throw _iteratorError;
+    }
+  }
 }

test/fixtures/transformation/es6-for-of/break/expected.js

@@ -2,44 +2,135 @@
 
 // labels
 
-foo: for (var _iterator = foo()[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+foo: {
+  var _iteratorNormalCompletion = true;
+  var _didIteratorError = false;
+  var _iteratorError = undefined;
+
+  try {
+    for (var _iterator = foo()[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
       var x = _step.value;
 
       while (true) {
-    if (_iterator["return"]) _iterator["return"]();
-
         break foo;
       }
-}
+    }
+  } catch (err) {
+    _didIteratorError = true;
+    _iteratorError = err;
+  } finally {
+    try {
+      if (!_iteratorNormalCompletion && _iterator["return"]) {
+        _iterator["return"]();
+      }
+    } finally {
+      if (_didIteratorError) {
+        throw _iteratorError;
+      }
+    }
+  }
+}foo: {
+  var _iteratorNormalCompletion2 = true;
+  var _didIteratorError2 = false;
+  var _iteratorError2 = undefined;
 
-foo: for (var _iterator2 = foo()[Symbol.iterator](), _step2; !(_step2 = _iterator2.next()).done;) {
+  try {
+    for (var _iterator2 = foo()[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
       var x = _step2.value;
 
       while (true) {
         break;
       }
-}
+    }
+  } catch (err) {
+    _didIteratorError2 = true;
+    _iteratorError2 = err;
+  } finally {
+    try {
+      if (!_iteratorNormalCompletion2 && _iterator2["return"]) {
+        _iterator2["return"]();
+      }
+    } finally {
+      if (_didIteratorError2) {
+        throw _iteratorError2;
+      }
+    }
+  }
+}foo: {
+  var _iteratorNormalCompletion3 = true;
+  var _didIteratorError3 = false;
+  var _iteratorError3 = undefined;
 
-foo: for (var _iterator3 = foo()[Symbol.iterator](), _step3; !(_step3 = _iterator3.next()).done;) {
+  try {
+    for (var _iterator3 = foo()[Symbol.iterator](), _step3; !(_iteratorNormalCompletion3 = (_step3 = _iterator3.next()).done); _iteratorNormalCompletion3 = true) {
       var x = _step3.value;
-  if (_iterator3["return"]) _iterator3["return"]();
 
       break foo;
-}
+    }
+  } catch (err) {
+    _didIteratorError3 = true;
+    _iteratorError3 = err;
+  } finally {
+    try {
+      if (!_iteratorNormalCompletion3 && _iterator3["return"]) {
+        _iterator3["return"]();
+      }
+    } finally {
+      if (_didIteratorError3) {
+        throw _iteratorError3;
+      }
+    }
+  }
+} // basic
 
-// basic
+var _iteratorNormalCompletion4 = true;
+var _didIteratorError4 = false;
+var _iteratorError4 = undefined;
 
-for (var _iterator4 = foo()[Symbol.iterator](), _step4; !(_step4 = _iterator4.next()).done;) {
+try {
+  for (var _iterator4 = foo()[Symbol.iterator](), _step4; !(_iteratorNormalCompletion4 = (_step4 = _iterator4.next()).done); _iteratorNormalCompletion4 = true) {
     var x = _step4.value;
-  if (_iterator4["return"]) _iterator4["return"]();
 
     break;
+  }
+} catch (err) {
+  _didIteratorError4 = true;
+  _iteratorError4 = err;
+} finally {
+  try {
+    if (!_iteratorNormalCompletion4 && _iterator4["return"]) {
+      _iterator4["return"]();
+    }
+  } finally {
+    if (_didIteratorError4) {
+      throw _iteratorError4;
+    }
+  }
 }
 
-for (var _iterator5 = foo()[Symbol.iterator](), _step5; !(_step5 = _iterator5.next()).done;) {
+var _iteratorNormalCompletion5 = true;
+var _didIteratorError5 = false;
+var _iteratorError5 = undefined;
+
+try {
+  for (var _iterator5 = foo()[Symbol.iterator](), _step5; !(_iteratorNormalCompletion5 = (_step5 = _iterator5.next()).done); _iteratorNormalCompletion5 = true) {
     var x = _step5.value;
 
     while (true) {
       break;
     }
+  }
+} catch (err) {
+  _didIteratorError5 = true;
+  _iteratorError5 = err;
+} finally {
+  try {
+    if (!_iteratorNormalCompletion5 && _iterator5["return"]) {
+      _iterator5["return"]();
+    }
+  } finally {
+    if (_didIteratorError5) {
+      throw _iteratorError5;
+    }
+  }
 }

test/fixtures/transformation/es6-for-of/identifier/expected.js

@@ -1,5 +1,24 @@
 "use strict";
 
-for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+var _iteratorNormalCompletion = true;
+var _didIteratorError = false;
+var _iteratorError = undefined;
+
+try {
+  for (var _iterator = arr[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
     i = _step.value;
+  }
+} catch (err) {
+  _didIteratorError = true;
+  _iteratorError = err;
+} finally {
+  try {
+    if (!_iteratorNormalCompletion && _iterator["return"]) {
+      _iterator["return"]();
+    }
+  } finally {
+    if (_didIteratorError) {
+      throw _iteratorError;
+    }
+  }
 }

test/fixtures/transformation/es6-for-of/let/expected.js

@@ -1,5 +1,24 @@
 "use strict";
 
-for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+var _iteratorNormalCompletion = true;
+var _didIteratorError = false;
+var _iteratorError = undefined;
+
+try {
+  for (var _iterator = arr[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
     var i = _step.value;
+  }
+} catch (err) {
+  _didIteratorError = true;
+  _iteratorError = err;
+} finally {
+  try {
+    if (!_iteratorNormalCompletion && _iterator["return"]) {
+      _iterator["return"]();
+    }
+  } finally {
+    if (_didIteratorError) {
+      throw _iteratorError;
+    }
+  }
 }

test/fixtures/transformation/es6-for-of/member-expression/expected.js

@@ -1,5 +1,24 @@
 "use strict";
 
-for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+var _iteratorNormalCompletion = true;
+var _didIteratorError = false;
+var _iteratorError = undefined;
+
+try {
+  for (var _iterator = arr[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
     obj.prop = _step.value;
+  }
+} catch (err) {
+  _didIteratorError = true;
+  _iteratorError = err;
+} finally {
+  try {
+    if (!_iteratorNormalCompletion && _iterator["return"]) {
+      _iterator["return"]();
+    }
+  } finally {
+    if (_didIteratorError) {
+      throw _iteratorError;
+    }
+  }
 }

test/fixtures/transformation/es6-for-of/multiple/expected.js

@@ -1,9 +1,47 @@
 "use strict";
 
-for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+var _iteratorNormalCompletion = true;
+var _didIteratorError = false;
+var _iteratorError = undefined;
+
+try {
+  for (var _iterator = arr[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
     var i = _step.value;
+  }
+} catch (err) {
+  _didIteratorError = true;
+  _iteratorError = err;
+} finally {
+  try {
+    if (!_iteratorNormalCompletion && _iterator["return"]) {
+      _iterator["return"]();
+    }
+  } finally {
+    if (_didIteratorError) {
+      throw _iteratorError;
+    }
+  }
 }
 
-for (var _iterator2 = numbers[Symbol.iterator](), _step2; !(_step2 = _iterator2.next()).done;) {
+var _iteratorNormalCompletion2 = true;
+var _didIteratorError2 = false;
+var _iteratorError2 = undefined;
+
+try {
+  for (var _iterator2 = numbers[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
     var i = _step2.value;
+  }
+} catch (err) {
+  _didIteratorError2 = true;
+  _iteratorError2 = err;
+} finally {
+  try {
+    if (!_iteratorNormalCompletion2 && _iterator2["return"]) {
+      _iterator2["return"]();
+    }
+  } finally {
+    if (_didIteratorError2) {
+      throw _iteratorError2;
+    }
+  }
 }

test/fixtures/transformation/es6-for-of/var/expected.js

@@ -1,5 +1,24 @@
 "use strict";
 
-for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+var _iteratorNormalCompletion = true;
+var _didIteratorError = false;
+var _iteratorError = undefined;
+
+try {
+  for (var _iterator = arr[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
     var i = _step.value;
+  }
+} catch (err) {
+  _didIteratorError = true;
+  _iteratorError = err;
+} finally {
+  try {
+    if (!_iteratorNormalCompletion && _iterator["return"]) {
+      _iterator["return"]();
+    }
+  } finally {
+    if (_didIteratorError) {
+      throw _iteratorError;
+    }
+  }
 }

test/fixtures/transformation/es7-comprehensions/arguments/expected.js

@@ -5,12 +5,30 @@ function add() {
 
   return (function () {
     var _ref = [];
+    var _iteratorNormalCompletion = true;
+    var _didIteratorError = false;
+    var _iteratorError = undefined;
 
-    for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+    try {
+      for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
         var i = _step.value;
 
         _ref.push(i * _arguments[0]);
       }
+    } catch (err) {
+      _didIteratorError = true;
+      _iteratorError = err;
+    } finally {
+      try {
+        if (!_iteratorNormalCompletion && _iterator["return"]) {
+          _iterator["return"]();
+        }
+      } finally {
+        if (_didIteratorError) {
+          throw _iteratorError;
+        }
+      }
+    }
 
     return _ref;
   })();

test/fixtures/transformation/es7-comprehensions/array-expression-single-if/expected.js

@@ -2,14 +2,32 @@
 
 var arr = (function () {
   var _arr = [];
+  var _iteratorNormalCompletion = true;
+  var _didIteratorError = false;
+  var _iteratorError = undefined;
 
-  for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+  try {
+    for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
       var i = _step.value;
 
       if (i > 1) {
         _arr.push(i * i);
       }
     }
+  } catch (err) {
+    _didIteratorError = true;
+    _iteratorError = err;
+  } finally {
+    try {
+      if (!_iteratorNormalCompletion && _iterator["return"]) {
+        _iterator["return"]();
+      }
+    } finally {
+      if (_didIteratorError) {
+        throw _iteratorError;
+      }
+    }
+  }
 
   return _arr;
 })();

test/fixtures/transformation/es7-comprehensions/array-expression-single/expected.js

@@ -2,12 +2,30 @@
 
 var arr = (function () {
   var _arr = [];
+  var _iteratorNormalCompletion = true;
+  var _didIteratorError = false;
+  var _iteratorError = undefined;
 
-  for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+  try {
+    for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
       var i = _step.value;
 
       _arr.push(i * i);
     }
+  } catch (err) {
+    _didIteratorError = true;
+    _iteratorError = err;
+  } finally {
+    try {
+      if (!_iteratorNormalCompletion && _iterator["return"]) {
+        _iterator["return"]();
+      }
+    } finally {
+      if (_didIteratorError) {
+        throw _iteratorError;
+      }
+    }
+  }
 
   return _arr;
 })();

test/fixtures/transformation/es7-comprehensions/array-multiple-if/expected.js

@@ -2,17 +2,53 @@
 
 var seattlers = (function () {
   var _seattlers = [];
+  var _iteratorNormalCompletion = true;
+  var _didIteratorError = false;
+  var _iteratorError = undefined;
 
-  for (var _iterator = countries[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+  try {
+    for (var _iterator = countries[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
       var customers = _step.value;
+      var _iteratorNormalCompletion2 = true;
+      var _didIteratorError2 = false;
+      var _iteratorError2 = undefined;
 
-    for (var _iterator2 = customers[Symbol.iterator](), _step2; !(_step2 = _iterator2.next()).done;) {
+      try {
+        for (var _iterator2 = customers[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
           var c = _step2.value;
 
           if (c.city == "Seattle") {
             _seattlers.push({ name: c.name, age: c.age });
           }
         }
+      } catch (err) {
+        _didIteratorError2 = true;
+        _iteratorError2 = err;
+      } finally {
+        try {
+          if (!_iteratorNormalCompletion2 && _iterator2["return"]) {
+            _iterator2["return"]();
+          }
+        } finally {
+          if (_didIteratorError2) {
+            throw _iteratorError2;
+          }
+        }
+      }
+    }
+  } catch (err) {
+    _didIteratorError = true;
+    _iteratorError = err;
+  } finally {
+    try {
+      if (!_iteratorNormalCompletion && _iterator["return"]) {
+        _iterator["return"]();
+      }
+    } finally {
+      if (_didIteratorError) {
+        throw _iteratorError;
+      }
+    }
   }
 
   return _seattlers;

test/fixtures/transformation/es7-comprehensions/array-multiple/expected.js

@@ -2,15 +2,51 @@
 
 var arr = (function () {
   var _arr = [];
+  var _iteratorNormalCompletion = true;
+  var _didIteratorError = false;
+  var _iteratorError = undefined;
 
-  for (var _iterator = "abcdefgh".split("")[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+  try {
+    for (var _iterator = "abcdefgh".split("")[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
       var x = _step.value;
+      var _iteratorNormalCompletion2 = true;
+      var _didIteratorError2 = false;
+      var _iteratorError2 = undefined;
 
-    for (var _iterator2 = "12345678".split("")[Symbol.iterator](), _step2; !(_step2 = _iterator2.next()).done;) {
+      try {
+        for (var _iterator2 = "12345678".split("")[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
           var y = _step2.value;
 
           _arr.push(x + y);
         }
+      } catch (err) {
+        _didIteratorError2 = true;
+        _iteratorError2 = err;
+      } finally {
+        try {
+          if (!_iteratorNormalCompletion2 && _iterator2["return"]) {
+            _iterator2["return"]();
+          }
+        } finally {
+          if (_didIteratorError2) {
+            throw _iteratorError2;
+          }
+        }
+      }
+    }
+  } catch (err) {
+    _didIteratorError = true;
+    _iteratorError = err;
+  } finally {
+    try {
+      if (!_iteratorNormalCompletion && _iterator["return"]) {
+        _iterator["return"]();
+      }
+    } finally {
+      if (_didIteratorError) {
+        throw _iteratorError;
+      }
+    }
   }
 
   return _arr;

test/fixtures/transformation/es7-comprehensions/array-single-if/expected.js

@@ -2,14 +2,32 @@
 
 var arr = (function () {
   var _arr = [];
+  var _iteratorNormalCompletion = true;
+  var _didIteratorError = false;
+  var _iteratorError = undefined;
 
-  for (var _iterator = nums[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+  try {
+    for (var _iterator = nums[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
       var i = _step.value;
 
       if (i > 1) {
         _arr.push(i * i);
       }
     }
+  } catch (err) {
+    _didIteratorError = true;
+    _iteratorError = err;
+  } finally {
+    try {
+      if (!_iteratorNormalCompletion && _iterator["return"]) {
+        _iterator["return"]();
+      }
+    } finally {
+      if (_didIteratorError) {
+        throw _iteratorError;
+      }
+    }
+  }
 
   return _arr;
 })();

test/fixtures/transformation/es7-comprehensions/array-single/expected.js

@@ -2,12 +2,30 @@
 
 var arr = (function () {
   var _arr = [];
+  var _iteratorNormalCompletion = true;
+  var _didIteratorError = false;
+  var _iteratorError = undefined;
 
-  for (var _iterator = nums[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+  try {
+    for (var _iterator = nums[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
       var i = _step.value;
 
       _arr.push(i * i);
     }
+  } catch (err) {
+    _didIteratorError = true;
+    _iteratorError = err;
+  } finally {
+    try {
+      if (!_iteratorNormalCompletion && _iterator["return"]) {
+        _iterator["return"]();
+      }
+    } finally {
+      if (_didIteratorError) {
+        throw _iteratorError;
+      }
+    }
+  }
 
   return _arr;
 })();

test/fixtures/transformation/es7-comprehensions/array-this/expected.js

@@ -5,12 +5,30 @@ function add() {
 
   return (function () {
     var _ref = [];
+    var _iteratorNormalCompletion = true;
+    var _didIteratorError = false;
+    var _iteratorError = undefined;
 
-    for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+    try {
+      for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
         var i = _step.value;
 
         _ref.push(i * _this.multiplier);
       }
+    } catch (err) {
+      _didIteratorError = true;
+      _iteratorError = err;
+    } finally {
+      try {
+        if (!_iteratorNormalCompletion && _iterator["return"]) {
+          _iterator["return"]();
+        }
+      } finally {
+        if (_didIteratorError) {
+          throw _iteratorError;
+        }
+      }
+    }
 
     return _ref;
   })();

test/fixtures/transformation/runtime/es6-for-of/expected.js

@@ -2,6 +2,25 @@
 
 var _core = require("babel-runtime/core-js")["default"];
 
-for (var _iterator = _core.$for.getIterator(arr), _step; !(_step = _iterator.next()).done;) {
+var _iteratorNormalCompletion = true;
+var _didIteratorError = false;
+var _iteratorError = undefined;
+
+try {
+  for (var _iterator = _core.$for.getIterator(arr), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
     var i = _step.value;
+  }
+} catch (err) {
+  _didIteratorError = true;
+  _iteratorError = err;
+} finally {
+  try {
+    if (!_iteratorNormalCompletion && _iterator["return"]) {
+      _iterator["return"]();
+    }
+  } finally {
+    if (_didIteratorError) {
+      throw _iteratorError;
+    }
+  }
 }

test/fixtures/transformation/runtime/es7-array-comprehensions/expected.js

@@ -4,12 +4,30 @@ var _core = require("babel-runtime/core-js")["default"];
 
 var arr = (function () {
   var _arr = [];
+  var _iteratorNormalCompletion = true;
+  var _didIteratorError = false;
+  var _iteratorError = undefined;
 
-  for (var _iterator = _core.$for.getIterator(nums), _step; !(_step = _iterator.next()).done;) {
+  try {
+    for (var _iterator = _core.$for.getIterator(nums), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
       var i = _step.value;
 
       _arr.push(i * i);
     }
+  } catch (err) {
+    _didIteratorError = true;
+    _iteratorError = err;
+  } finally {
+    try {
+      if (!_iteratorNormalCompletion && _iterator["return"]) {
+        _iterator["return"]();
+      }
+    } finally {
+      if (_didIteratorError) {
+        throw _iteratorError;
+      }
+    }
+  }
 
   return _arr;
 })();