stateProvince() function in Query.php produces MySQL errors

The following code in Query.php is producing an IN query with unquoted strings for state/province.

/**

• where / qill clause for state/province AND country (if present)
  *
• @return void
• @access public
  */
  function stateProvince( &$values, $status = null )
  {
  list( $name, $op, $value, $grouping, $wildcard ) = $values;

if (! is_array( $value ) )

{ // force the state to be an array $value = array( $value ); }

$stateClause =
'civicrm_state_province.id IN (' .
implode( ',', $value ) .
')';