only use raw type references in coreAliasing on Symbol - fixes #421

lib/6to5/transformation/transformers/optional-core-aliasing.js

@@ -31,8 +31,8 @@ exports.ast = {
             this.skip();
             return t.prependToMemberExpression(node, file._coreId);
           }
-        } else if (t.isIdentifier(node) && !t.isMemberExpression(parent) && t.isReferenced(node, parent) && coreHas(node)) {
-          // new Promise -> new _core.Promise
+        } else if (t.isIdentifier(node) && !t.isMemberExpression(parent) && t.isReferenced(node, parent) && node.name === "Symbol") {
+          // new Symbol -> new _core.Symbol
           return t.memberExpression(file._coreId, node);
         } else if (t.isCallExpression(node)) {
           // arr[Symbol.iterator]() -> _core.$for.getIterator(arr)

test/fixtures/transformation/optional-core-aliasing/ignore-natives/actual.js

@@ -0,0 +1 @@
+obj.constructor === Object;

test/fixtures/transformation/optional-core-aliasing/ignore-natives/expected.js

@@ -0,0 +1,9 @@
+"use strict";
+
+var _interopRequire = function (obj) {
+  return obj && (obj["default"] || obj);
+};
+
+var _core = _interopRequire(require("core-js/library"));
+
+obj.constructor === Object;

test/fixtures/transformation/optional-core-aliasing/map-symbol/actual.js

@@ -0,0 +1,2 @@
+Symbol("test");
+Symbol();

test/fixtures/transformation/optional-core-aliasing/map-symbol/expected.js

@@ -0,0 +1,10 @@
+"use strict";
+
+var _interopRequire = function (obj) {
+  return obj && (obj["default"] || obj);
+};
+
+var _core = _interopRequire(require("core-js/library"));
+
+_core.Symbol("test");
+_core.Symbol();