nsIRDFDataSource* ds = NS_STATIC_CAST(nsIRDFDataSource*, mDataSources[i]); rv = ds->HasArcIn(aNode, aArc, result);
rv = mDataSources[i]->HasArcIn(aNode, aArc, result);
CompositeDataSourceImpl::HasArcIn(nsIRDFNode *aNode, nsIRDFResource *aArc, PRBool *result){    nsresult rv;    *result = PR_FALSE;    PRInt32 count = mDataSources.Count();    for (PRInt32 i = 0; i < count; ++i) {        nsIRDFDataSource* ds = NS_STATIC_CAST(nsIRDFDataSource*, mDataSources[i]);        rv = ds->HasArcIn(aNode, aArc, result);        if (NS_FAILED(rv)) return rv;        if (*result == PR_TRUE)            return NS_OK;    }    return NS_OK;}