Cannot use null as value for a positional constraint ---------------------------------------------------- Key: DROOLS-51 URL: https://issues.jboss.org/browse/DROOLS-51 Project: Drools Issue Type: Bug Security Level: Public(Everyone can see) Reporter: Mario Fusco Assignee: Mario Fusco Fix For: 5.6, 6.0.0.Alpha1 The following DRL generates an infinite loop, while it works correctly if you replace the positional constraint with a normal one as in the commented pattern. {code} declare Outer end declare Inner outer : Outer end rule "Init" when then insert( new Inner( null ) ); insert( new Outer( ) ); end rule "Bind" when $o : Outer( ) $i : Inner( null ; ) // $i : Inner( outer == null ) then modify ( $i ) { setOuter( $o ); } end {code}