diff --git a/IdeSession/Query.hs b/IdeSession/Query.hs
--- a/IdeSession/Query.hs
+++ b/IdeSession/Query.hs
@@ -297,7 +297,8 @@
                  -> [IdInfo]
     autocomplete cache mapOfTries modName name =
         let name' = BSSC.pack name
-            n     = last (BSSC.split '.' name')
+            ns    = BSSC.split '.' name'
+            n     = if null ns then BSSC.empty else last ns
         in filter (\idInfo -> name `isInfixOf` idInfoQN idInfo)
              $ concatMap (toLazyList . StrictList.map (removeExplicitSharing Proxy cache))
              . StrictTrie.elems
diff --git a/ide-backend.cabal b/ide-backend.cabal
--- a/ide-backend.cabal
+++ b/ide-backend.cabal
@@ -1,5 +1,5 @@
 name:                 ide-backend
-version:              0.9.0.6
+version:              0.9.0.7
 synopsis:             An IDE backend library
 description:          See README.md for more details
 license:              MIT