diff --git a/package.json b/package.json
index 822bf422..2f7b2d2b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "eslint-plugin-angular",
-  "version": "3.1.0",
+  "version": "3.1.1",
   "description": "ESLint rules for AngularJS projects",
   "main": "index.js",
   "scripts": {
diff --git a/rules/file-name.js b/rules/file-name.js
index 64576ae8..d5d47f8c 100644
--- a/rules/file-name.js
+++ b/rules/file-name.js
@@ -46,7 +46,7 @@ function handleModuleCase(node, context, defaultFilename) {
     });
 
     // Check that the definition is an import declaration.
-    if (variable.defs[0].parent.type !== 'ImportDeclaration') {
+    if (!(variable && variable.defs && variable.defs[0] && variable.defs[0].parent && variable.defs[0].parent.type === 'ImportDeclaration')) {
         return defaultFilename;
     }