--- biber-2.17/lib/Biber/Section.pm
+++ biber-2.18/lib/Biber/Section.pm
@@ -429,7 +429,7 @@
 
 sub del_everykeys {
   my $self = shift;
-  $self->{everykey} = undef
+  $self->{everykey} = undef;
   $self->{everykey_lc} = undef;
   return;
 }