allow MemberExpressions in for-of head

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

@@ -0,0 +1,3 @@
+for (obj.prop of arr) {
+
+}

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

@@ -0,0 +1,12 @@
+"use strict";
+
+for (var _iterator = arr, _isArray = Array.isArray(_iterator), _i = 0, _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+  if (_isArray) {
+    if (_i >= _iterator.length) break;
+    obj.prop = _iterator[_i++];
+  } else {
+    _i = _iterator.next();
+    if (_i.done) break;
+    obj.prop = _i.value;
+  }
+}

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

@@ -0,0 +1,3 @@
+for (obj.prop of arr) {
+
+}

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

@@ -0,0 +1,5 @@
+"use strict";
+
+for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
+  obj.prop = _step.value;
+}