src/Pure/Isar/outer_syntax.scala

--- a/src/Pure/Isar/outer_syntax.scala	Fri May 01 15:33:43 2015 +0200
+++ b/src/Pure/Isar/outer_syntax.scala	Sun May 03 00:01:10 2015 +0200
@@ -33,7 +33,7 @@
           result += '\\'
           if (c < 10) result += '0'
           if (c < 100) result += '0'
-          result ++= (c.asInstanceOf[Int].toString)
+          result ++= c.asInstanceOf[Int].toString
         }
         else result += c
       }