diff -r 8f4b72f0c15d -r 9e74cf11e4a4 src/Pure/Syntax/lexicon.ML
--- a/src/Pure/Syntax/lexicon.ML	Thu Jul 02 16:53:55 1998 +0200
+++ b/src/Pure/Syntax/lexicon.ML	Thu Jul 02 17:26:47 1998 +0200
@@ -229,7 +229,7 @@
 val scan_str =
   $$ "'" |-- $$ "'" |--
     !! (fn (cs, _) => "Inner lexical error: malformed literal string at " ^
-      quote ("''" ^ beginning cs))
+      quote ("''" ^ Symbol.beginning cs))
     (Scan.repeat scan_chr --| $$ "'" --| $$ "'");