protected function _processExpressions()
    {
        $types = [];
        $typeMap = $this->getTypeMap();

        $columns = $this->_columnNames();
        foreach ($columns as $c) {
            if (!is_scalar($c)) {
                continue;
            }
            $types[$c] = $typeMap->type($c);
        }

        $types = $this->_requiresToExpressionCasting($types);

        if (empty($types)) {
            return;
        }

        foreach ($this->_values as $row => $values) {
            foreach ($types as $col => $type) {
                /* @var \Cake\Database\Type\ExpressionTypeInterface $type */
                $this->_values[$row][$col] = $type->toExpression($values[$col]);
            }
        }
        $this->_castedExpressions = true;
    }