public static TypeCompatibilityObligation newInstance ( PExp exp , PType etype , PType atype , IPOContextStack ctxt , IPogAssistantFactory assistantFactory ) throws AnalysisException { TypeCompatibilityObligation sto = new TypeCompatibilityObligation ( exp , etype , atype , ctxt , assistantFactory ) ; if ( sto . getValueTree ( ) != null ) { return sto ; } return null ; }
Factory Method since we need to return null STOs ( which should be discarded