Index: std_hilite/STD_syntax_highlight
===================================================================
--- std_hilite/STD_syntax_highlight	(revision 28640)
+++ std_hilite/STD_syntax_highlight	(working copy)
@@ -447,6 +447,14 @@
     my ($last_tree,$buffer, $last_type) = ("","","");
     for my $i (0 .. @loc-1) {
         next unless defined $loc[$i];
+
+        # XXX Bug? @loc is too long for $src_text.
+        # Extra @loc[-2,-1] are 'vws' and 'eat_terminator'.
+        if ( $i >= length $src_text ) {
+            #warn "\$i was $i, which is past the end of \$src_text\n";
+            next;
+        }
+
         my $c = substr($src_text,$i,1);
         my $tree = "";
         for my $action_ref (@{$loc[$i]}) {