fix #660?

CHANGELOG.md

@@ -4,6 +4,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 This change log adheres to standards from [Keep a CHANGELOG](http://keepachangelog.com).
 
 ## [Unreleased]
+### Fixed
+- attempt to fix crash in [`no-mutable-exports`]. ([#660])
 
 
 ## [2.2.0] - 2016-11-07
@@ -424,6 +426,7 @@ for info on changes for earlier releases.
 [#157]: https://github.com/benmosher/eslint-plugin-import/pull/157
 [#314]: https://github.com/benmosher/eslint-plugin-import/pull/314
 
+[#660]: https://github.com/benmosher/eslint-plugin-import/issues/660
 [#653]: https://github.com/benmosher/eslint-plugin-import/issues/653
 [#609]: https://github.com/benmosher/eslint-plugin-import/issues/609
 [#604]: https://github.com/benmosher/eslint-plugin-import/issues/604

src/rules/no-mutable-exports.js

@@ -15,7 +15,7 @@ module.exports = {
       for (let variable of variables) {
         if (variable.name === name) {
           for (let def of variable.defs) {
-            if (def.type === 'Variable') {
+            if (def.type === 'Variable' && def.parent) {
               checkDeclaration(def.parent)
             }
           }

tests/src/rules/no-mutable-exports.js

@@ -62,5 +62,15 @@ ruleTester.run('no-mutable-exports', rule, {
       code: 'var count = 1\nexport default count',
       errors: ['Exporting mutable \'var\' binding, use \'const\' instead.'],
     }),
+
+    // todo: undeclared globals
+    // test({
+    //   code: 'count = 1\nexport { count }',
+    //   errors: ['Exporting mutable global binding, use \'const\' instead.'],
+    // }),
+    // test({
+    //   code: 'count = 1\nexport default count',
+    //   errors: ['Exporting mutable global binding, use \'const\' instead.'],
+    // }),
   ],
 })