$query = $this->createQuery();
$constraint = array();
$constraint[] = $query->contains('fieldA', $valueA);
$constraint[] = $query->contains('fieldB', $valueB);

How can I use this $contraint in a matching condition ????
$query->matching($constraint) - does not work !
$query->matching($query->logicalAnd($contraint)) - also does not work !