don't transform flow module nodes

lib/babel/transformation/transformers/es6/modules.js

@@ -5,6 +5,9 @@ var t = require("../../../types");
 exports.check = require("../internal/modules").check;
 
 exports.ImportDeclaration = function (node, parent, scope, file) {
+  // flow type
+  if (node.isType) return;
+
   var nodes = [];
 
   if (node.specifiers.length) {
@@ -24,6 +27,9 @@ exports.ImportDeclaration = function (node, parent, scope, file) {
 };
 
 exports.ExportDeclaration = function (node, parent, scope, file) {
+  // flow type
+  if (t.isTypeAlias(node.declaration)) return;
+
   var nodes = [];
   var i;
 

lib/babel/transformation/transformers/internal/modules.js

@@ -24,6 +24,9 @@ exports.ImportDeclaration = resolveModuleSource;
 exports.ExportDeclaration = function (node, parent, scope) {
   resolveModuleSource.apply(null, arguments);
 
+  // flow type
+  if (node.isType) return;
+
   var declar = node.declaration;
 
   if (node.default) {