diff --git a/Shorewall/Perl/Shorewall/Chains.pm b/Shorewall/Perl/Shorewall/Chains.pm
index 4eaaeee02..054882513 100644
--- a/Shorewall/Perl/Shorewall/Chains.pm
+++ b/Shorewall/Perl/Shorewall/Chains.pm
@@ -43,7 +43,6 @@ our @EXPORT = qw(
 		  ensure_manual_chain
 		  log_rule_limit
 		  dont_optimize
-		  optimize_okay
 		  dont_delete
 		  dont_move
 
@@ -660,6 +659,8 @@ sub add_reference ( $$ ) {
 
     my $toref = reftype $to ? $to : $chain_table{$fromref->{table}}{$to};
 
+    assert($toref);
+
     $toref->{references}{$fromref->{name}}++;
 }
 
@@ -671,6 +672,8 @@ sub delete_reference( $$ ) {
 
     my $toref = reftype $to ? $to : $chain_table{$fromref->{table}}{$to};
 
+    assert( $toref );
+
     delete $toref->{references}{$fromref->{name}} unless --$toref->{references}{$fromref->{name}} > 0;
 }
 
@@ -1259,21 +1262,6 @@ sub dont_optimize( $ ) {
     $chainref;
 }
 
-#
-# Reverse the effect of dont_optimize
-#
-sub optimize_okay( $ ) {
-    my $chain = shift;
-
-    my $chainref = reftype $chain ? $chain : $filter_table->{$chain};
-
-    $chainref->{dont_optimize} = 0;
-
-    trace( $chainref, 'O', undef, '' ) if $debug;
-
-    $chainref;
-}
-
 #
 # Set the dont_optimize and dont_delete flags for a chain
 #