jena-arq/testing/DAWG-Final/algebra/opt-filter-3.rq

PREFIX :    <http://example/>

SELECT *
{ 
    :x :p ?v . 
    { :x :q ?w 
      # ?v is not in scope so ?v2 never set
      OPTIONAL {  :x :p ?v2 FILTER(?v = 1) }
    }
}