diff --git a/io/src/main/scala/sbt/io/IO.scala b/io/src/main/scala/sbt/io/IO.scala
index bdd28035..802f98ae 100644
--- a/io/src/main/scala/sbt/io/IO.scala
+++ b/io/src/main/scala/sbt/io/IO.scala
@@ -558,7 +558,7 @@ object IO {
       isEmpty.getOrElseUpdate(f, dirs(f) && f.isDirectory && (f.listFiles forall visit))
 
     dirs foreach visit
-    for ((f, true) <- isEmpty) f.delete
+    for (case (f, true) <- isEmpty) f.delete
   }
 
   /** Deletes each file or directory (recursively) in `files`. */