diff -r ff7ce802be52 -r 0af9e7e4476f src/Pure/General/symbol.scala
--- a/src/Pure/General/symbol.scala	Mon Mar 01 18:31:11 2021 +0100
+++ b/src/Pure/General/symbol.scala	Mon Mar 01 19:41:52 2021 +0100
@@ -117,7 +117,7 @@
       private val matcher = new Matcher(text)
       private var i = 0
       def hasNext: Boolean = i < text.length
-      def next: Symbol =
+      def next(): Symbol =
       {
         val n = matcher(i, text.length)
         val s =