BIND bug in nested graph pattern

[Gokhan Soydan]

Hello,

Using a BIND in a nested graph pattern (a basic, OPTIONAL or UNION 
pattern) with an input argument that was assigned in the parent graph 
pattern doesn't work. The following example query returns no value for 
?x, whereas it should return the value of ?s assigned to ?x

SELECT ?x
WHERE {
    ?s ?p ?o
    {
        BIND( ?s AS ?x )
    }
}


This is the case both in ARQ 2.8.1 and ARQ 2.8.7.

Thanks,
Gokhan