PhpMssqlAutoloader.php in Drupal driver for SQL Server and SQL Azure 8.2
File
drivers/lib/Drupal/Driver/Database/sqlsrv/PhpMssqlAutoloader.phpView source
<?php
$loader = new \Composer\Autoload\ClassLoader();
$loader
->addPsr4('mssql\\', __DIR__ . DIRECTORY_SEPARATOR . 'mssql' . DIRECTORY_SEPARATOR . 'src');
$loader
->register();