diff --git a/src/app/language-mode.coffee b/src/app/language-mode.coffee
index 19c376f1b..2ca57a60e 100644
--- a/src/app/language-mode.coffee
+++ b/src/app/language-mode.coffee
@@ -55,6 +55,7 @@ class LanguageMode
       @grammar = @buffer.project.grammarForFilePath(path, pathContents)
     else
       @grammar = syntax.grammarForFilePath(path, pathContents)
+    throw new Error("No grammar found for path: #{path}") unless @grammar
     previousGrammar isnt @grammar
 
   isQuote: (string) ->