diff --git a/lib/Doctrine/DBAL/Cache/ResultCacheStatement.php b/lib/Doctrine/DBAL/Cache/ResultCacheStatement.php
index 34381e23b1c..07a6c220611 100644
--- a/lib/Doctrine/DBAL/Cache/ResultCacheStatement.php
+++ b/lib/Doctrine/DBAL/Cache/ResultCacheStatement.php
@@ -244,7 +244,7 @@ public function fetchAllNumeric(): array
 
         $this->store($data);
 
-        return array_map('array_values', $this->data);
+        return array_map('array_values', $data);
     }
 
     /**
diff --git a/lib/Doctrine/DBAL/Configuration.php b/lib/Doctrine/DBAL/Configuration.php
index 6d2497b632d..545b0ffb0b4 100644
--- a/lib/Doctrine/DBAL/Configuration.php
+++ b/lib/Doctrine/DBAL/Configuration.php
@@ -73,7 +73,7 @@ public function setResultCacheImpl(Cache $cacheImpl)
      *
      * @deprecated Use Configuration::setSchemaAssetsFilter() instead
      *
-     * @param string $filterExpression
+     * @param string|null $filterExpression
      *
      * @return void
      */
diff --git a/lib/Doctrine/DBAL/Driver/IBMDB2/DB2Connection.php b/lib/Doctrine/DBAL/Driver/IBMDB2/DB2Connection.php
index dc2701e344a..bdc52551f52 100644
--- a/lib/Doctrine/DBAL/Driver/IBMDB2/DB2Connection.php
+++ b/lib/Doctrine/DBAL/Driver/IBMDB2/DB2Connection.php
@@ -37,7 +37,7 @@
 class DB2Connection implements ConnectionInterface, ServerInfoAwareConnection
 {
     /** @var resource */
-    private $conn = null;
+    private $conn;
 
     /**
      * @internal The connection can be only instantiated by its driver.
@@ -93,7 +93,7 @@ public function prepare($sql)
         $stmt = @db2_prepare($this->conn, $sql);
 
         if ($stmt === false) {
-            throw PrepareFailed::new(error_get_last()['message']);
+            throw PrepareFailed::new(error_get_last());
         }
 
         return new Statement($stmt);
diff --git a/lib/Doctrine/DBAL/Driver/IBMDB2/DB2Statement.php b/lib/Doctrine/DBAL/Driver/IBMDB2/DB2Statement.php
index 02cc6526907..c758a253d0a 100644
--- a/lib/Doctrine/DBAL/Driver/IBMDB2/DB2Statement.php
+++ b/lib/Doctrine/DBAL/Driver/IBMDB2/DB2Statement.php
@@ -455,9 +455,9 @@ public function free(): void
     /**
      * Casts a stdClass object to the given class name mapping its' properties.
      *
-     * @param stdClass      $sourceObject     Object to cast from.
-     * @param string|object $destinationClass Name of the class or class instance to cast to.
-     * @param mixed[]       $ctorArgs         Arguments to use for constructing the destination class instance.
+     * @param stdClass            $sourceObject     Object to cast from.
+     * @param class-string|object $destinationClass Name of the class or class instance to cast to.
+     * @param mixed[]             $ctorArgs         Arguments to use for constructing the destination class instance.
      *
      * @return object
      *
@@ -527,7 +527,7 @@ private function createTemporaryFile()
         $handle = @tmpfile();
 
         if ($handle === false) {
-            throw CannotCreateTemporaryFile::new(error_get_last()['message']);
+            throw CannotCreateTemporaryFile::new(error_get_last());
         }
 
         return $handle;
@@ -542,7 +542,7 @@ private function createTemporaryFile()
     private function copyStreamToStream($source, $target): void
     {
         if (@stream_copy_to_stream($source, $target) === false) {
-            throw CannotCopyStreamToStream::new(error_get_last()['message']);
+            throw CannotCopyStreamToStream::new(error_get_last());
         }
     }
 
@@ -554,7 +554,7 @@ private function copyStreamToStream($source, $target): void
     private function writeStringToStream(string $string, $target): void
     {
         if (@fwrite($target, $string) === false) {
-            throw CannotWriteToTemporaryFile::new(error_get_last()['message']);
+            throw CannotWriteToTemporaryFile::new(error_get_last());
         }
     }
 }
diff --git a/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/CannotCopyStreamToStream.php b/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/CannotCopyStreamToStream.php
index 8223a92d660..61244c1cc61 100644
--- a/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/CannotCopyStreamToStream.php
+++ b/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/CannotCopyStreamToStream.php
@@ -13,8 +13,17 @@
  */
 final class CannotCopyStreamToStream extends DB2Exception
 {
-    public static function new(string $message): self
+    /**
+     * @psalm-param array{message: string}|null $error
+     */
+    public static function new(?array $error): self
     {
-        return new self('Could not copy source stream to temporary file: ' . $message);
+        $message = 'Could not copy source stream to temporary file';
+
+        if ($error !== null) {
+            $message .= ': ' . $error['message'];
+        }
+
+        return new self($message);
     }
 }
diff --git a/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/CannotCreateTemporaryFile.php b/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/CannotCreateTemporaryFile.php
index 48b28dd33d3..d5481ed9e31 100644
--- a/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/CannotCreateTemporaryFile.php
+++ b/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/CannotCreateTemporaryFile.php
@@ -13,8 +13,17 @@
  */
 final class CannotCreateTemporaryFile extends DB2Exception
 {
-    public static function new(string $message): self
+    /**
+     * @psalm-param array{message: string}|null $error
+     */
+    public static function new(?array $error): self
     {
-        return new self('Could not create temporary file: ' . $message);
+        $message = 'Could not create temporary file';
+
+        if ($error !== null) {
+            $message .= ': ' . $error['message'];
+        }
+
+        return new self($message);
     }
 }
diff --git a/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/CannotWriteToTemporaryFile.php b/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/CannotWriteToTemporaryFile.php
index 8acc269a4ad..33d0b86cc4f 100644
--- a/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/CannotWriteToTemporaryFile.php
+++ b/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/CannotWriteToTemporaryFile.php
@@ -13,8 +13,17 @@
  */
 final class CannotWriteToTemporaryFile extends DB2Exception
 {
-    public static function new(string $message): self
+    /**
+     * @psalm-param array{message: string}|null $error
+     */
+    public static function new(?array $error): self
     {
-        return new self('Could not write string to temporary file: ' . $message);
+        $message = 'Could not write string to temporary file';
+
+        if ($error !== null) {
+            $message .= ': ' . $error['message'];
+        }
+
+        return new self($message);
     }
 }
diff --git a/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/PrepareFailed.php b/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/PrepareFailed.php
index f566df8d50d..035fd67f9c2 100644
--- a/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/PrepareFailed.php
+++ b/lib/Doctrine/DBAL/Driver/IBMDB2/Exception/PrepareFailed.php
@@ -13,8 +13,15 @@
  */
 final class PrepareFailed extends AbstractException
 {
-    public static function new(string $message): self
+    /**
+     * @psalm-param array{message: string}|null $error
+     */
+    public static function new(?array $error): self
     {
-        return new self($message);
+        if ($error === null) {
+            return new self('Unknown error');
+        }
+
+        return new self($error['message']);
     }
 }
diff --git a/lib/Doctrine/DBAL/Driver/OCI8/OCI8Statement.php b/lib/Doctrine/DBAL/Driver/OCI8/OCI8Statement.php
index d019d74576f..cbb8a851b27 100644
--- a/lib/Doctrine/DBAL/Driver/OCI8/OCI8Statement.php
+++ b/lib/Doctrine/DBAL/Driver/OCI8/OCI8Statement.php
@@ -299,8 +299,7 @@ public function bindParam($param, &$variable, $type = ParameterType::STRING, $le
         if ($type === ParameterType::LARGE_OBJECT) {
             $lob = oci_new_descriptor($this->_dbh, OCI_D_LOB);
 
-            $class = 'OCI-Lob';
-            assert($lob instanceof $class);
+            assert($lob !== false);
 
             $lob->writeTemporary($variable, OCI_TEMP_BLOB);
 
diff --git a/lib/Doctrine/DBAL/Driver/SQLAnywhere/Driver.php b/lib/Doctrine/DBAL/Driver/SQLAnywhere/Driver.php
index 95b59274e9e..81d88232dca 100644
--- a/lib/Doctrine/DBAL/Driver/SQLAnywhere/Driver.php
+++ b/lib/Doctrine/DBAL/Driver/SQLAnywhere/Driver.php
@@ -52,15 +52,15 @@ public function getName()
     /**
      * Build the connection string for given connection parameters and driver options.
      *
-     * @param string  $host          Host address to connect to.
-     * @param int     $port          Port to use for the connection (default to SQL Anywhere standard port 2638).
-     * @param string  $server        Database server name on the host to connect to.
-     *                               SQL Anywhere allows multiple database server instances on the same host,
-     *                               therefore specifying the server instance name to use is mandatory.
-     * @param string  $dbname        Name of the database on the server instance to connect to.
-     * @param string  $username      User name to use for connection authentication.
-     * @param string  $password      Password to use for connection authentication.
-     * @param mixed[] $driverOptions Additional parameters to use for the connection.
+     * @param string|null $host          Host address to connect to.
+     * @param int|null    $port          Port to use for the connection (default to SQL Anywhere standard port 2638).
+     * @param string|null $server        Database server name on the host to connect to.
+     *                              SQL Anywhere allows multiple database server instances on the same host,
+     *                              therefore specifying the server instance name to use is mandatory.
+     * @param string|null $dbname        Name of the database on the server instance to connect to.
+     * @param string      $username      User name to use for connection authentication.
+     * @param string      $password      Password to use for connection authentication.
+     * @param mixed[]     $driverOptions Additional parameters to use for the connection.
      *
      * @return string
      */
diff --git a/lib/Doctrine/DBAL/Driver/SQLAnywhere/SQLAnywhereStatement.php b/lib/Doctrine/DBAL/Driver/SQLAnywhere/SQLAnywhereStatement.php
index 1542276dba2..513e4a508ef 100644
--- a/lib/Doctrine/DBAL/Driver/SQLAnywhere/SQLAnywhereStatement.php
+++ b/lib/Doctrine/DBAL/Driver/SQLAnywhere/SQLAnywhereStatement.php
@@ -419,9 +419,9 @@ public function setFetchMode($fetchMode, $arg2 = null, $arg3 = null)
     /**
      * Casts a stdClass object to the given class name mapping its' properties.
      *
-     * @param stdClass      $sourceObject     Object to cast from.
-     * @param string|object $destinationClass Name of the class or class instance to cast to.
-     * @param mixed[]       $ctorArgs         Arguments to use for constructing the destination class instance.
+     * @param stdClass            $sourceObject     Object to cast from.
+     * @param class-string|object $destinationClass Name of the class or class instance to cast to.
+     * @param mixed[]             $ctorArgs         Arguments to use for constructing the destination class instance.
      *
      * @return object
      *
diff --git a/lib/Doctrine/DBAL/DriverManager.php b/lib/Doctrine/DBAL/DriverManager.php
index 5b12e4871bb..17ba8584da2 100644
--- a/lib/Doctrine/DBAL/DriverManager.php
+++ b/lib/Doctrine/DBAL/DriverManager.php
@@ -113,7 +113,7 @@ private function __construct()
      * <b>driverClass</b>:
      * The driver class to use.
      *
-     * @param  array{wrapperClass?: class-string<T>} $params
+     * @param array{wrapperClass?: class-string<T>} $params
      * @param Configuration|null                    $config       The configuration to use.
      * @param EventManager|null                     $eventManager The event manager to use.
      *
@@ -195,6 +195,7 @@ public static function getConnection(
                 throw Exception::invalidWrapperClass($params['wrapperClass']);
             }
 
+            /** @var class-string<Connection> $wrapperClass */
             $wrapperClass = $params['wrapperClass'];
         }
 
diff --git a/lib/Doctrine/DBAL/Event/SchemaColumnDefinitionEventArgs.php b/lib/Doctrine/DBAL/Event/SchemaColumnDefinitionEventArgs.php
index 2be445e38af..7c962a928f4 100644
--- a/lib/Doctrine/DBAL/Event/SchemaColumnDefinitionEventArgs.php
+++ b/lib/Doctrine/DBAL/Event/SchemaColumnDefinitionEventArgs.php
@@ -12,7 +12,7 @@
 class SchemaColumnDefinitionEventArgs extends SchemaEventArgs
 {
     /** @var Column|null */
-    private $column = null;
+    private $column;
 
     /**
      * Raw column data as fetched from the database.
diff --git a/lib/Doctrine/DBAL/Event/SchemaDropTableEventArgs.php b/lib/Doctrine/DBAL/Event/SchemaDropTableEventArgs.php
index 1236de401ab..072e1efb909 100644
--- a/lib/Doctrine/DBAL/Event/SchemaDropTableEventArgs.php
+++ b/lib/Doctrine/DBAL/Event/SchemaDropTableEventArgs.php
@@ -18,7 +18,7 @@ class SchemaDropTableEventArgs extends SchemaEventArgs
     private $platform;
 
     /** @var string|null */
-    private $sql = null;
+    private $sql;
 
     /**
      * @param string|Table $table
diff --git a/lib/Doctrine/DBAL/Event/SchemaIndexDefinitionEventArgs.php b/lib/Doctrine/DBAL/Event/SchemaIndexDefinitionEventArgs.php
index ca6bbf81f7e..055a19a7c27 100644
--- a/lib/Doctrine/DBAL/Event/SchemaIndexDefinitionEventArgs.php
+++ b/lib/Doctrine/DBAL/Event/SchemaIndexDefinitionEventArgs.php
@@ -12,7 +12,7 @@
 class SchemaIndexDefinitionEventArgs extends SchemaEventArgs
 {
     /** @var Index|null */
-    private $index = null;
+    private $index;
 
     /**
      * Raw index data as fetched from the database.
diff --git a/lib/Doctrine/DBAL/Platforms/AbstractPlatform.php b/lib/Doctrine/DBAL/Platforms/AbstractPlatform.php
index ba551574651..911daa8cb8b 100644
--- a/lib/Doctrine/DBAL/Platforms/AbstractPlatform.php
+++ b/lib/Doctrine/DBAL/Platforms/AbstractPlatform.php
@@ -132,7 +132,7 @@ abstract class AbstractPlatform
     public const TRIM_BOTH = TrimMode::BOTH;
 
     /** @var string[]|null */
-    protected $doctrineTypeMapping = null;
+    protected $doctrineTypeMapping;
 
     /**
      * Contains a list of all columns that should generate parseable column comments for type-detection
@@ -140,7 +140,7 @@ abstract class AbstractPlatform
      *
      * @var string[]|null
      */
-    protected $doctrineTypeComments = null;
+    protected $doctrineTypeComments;
 
     /** @var EventManager */
     protected $_eventManager;
@@ -1602,8 +1602,10 @@ public function getCreateTableSQL(Table $table, $createFlags = self::CREATE_INDE
                 }
             }
 
+            $name = $column->getQuotedName($this);
+
             $columnData = array_merge($column->toArray(), [
-                'name' => $column->getQuotedName($this),
+                'name' => $name,
                 'version' => $column->hasPlatformOption('version') ? $column->getPlatformOption('version') : false,
                 'comment' => $this->getColumnComment($column),
             ]);
@@ -1616,7 +1618,7 @@ public function getCreateTableSQL(Table $table, $createFlags = self::CREATE_INDE
                 $columnData['primary'] = true;
             }
 
-            $columns[$columnData['name']] = $columnData;
+            $columns[$name] = $columnData;
         }
 
         if (($createFlags & self::CREATE_FOREIGNKEYS) > 0) {
@@ -1742,7 +1744,7 @@ protected function _getCreateTableSQL($name, array $columns, array $options = []
 
         $query .= ')';
 
-        $sql[] = $query;
+        $sql = [$query];
 
         if (isset($options['foreignKeys'])) {
             foreach ((array) $options['foreignKeys'] as $definition) {
diff --git a/lib/Doctrine/DBAL/Platforms/Keywords/KeywordList.php b/lib/Doctrine/DBAL/Platforms/Keywords/KeywordList.php
index 860d9f21099..852a58aba2b 100644
--- a/lib/Doctrine/DBAL/Platforms/Keywords/KeywordList.php
+++ b/lib/Doctrine/DBAL/Platforms/Keywords/KeywordList.php
@@ -12,7 +12,7 @@
 abstract class KeywordList
 {
     /** @var string[]|null */
-    private $keywords = null;
+    private $keywords;
 
     /**
      * Checks if the given word is a keyword of this dialect/vendor platform.
diff --git a/lib/Doctrine/DBAL/Platforms/SQLServerPlatform.php b/lib/Doctrine/DBAL/Platforms/SQLServerPlatform.php
index 2b45883b3fa..b41f33bef46 100644
--- a/lib/Doctrine/DBAL/Platforms/SQLServerPlatform.php
+++ b/lib/Doctrine/DBAL/Platforms/SQLServerPlatform.php
@@ -1199,10 +1199,10 @@ public function getAsciiStringTypeDeclarationSQL(array $column): string
         $length = $column['length'] ?? null;
 
         if (! isset($column['fixed'])) {
-            return sprintf('VARCHAR(%d)', $length);
+            return sprintf('VARCHAR(%d)', $length ?? 255);
         }
 
-        return sprintf('CHAR(%d)', $length);
+        return sprintf('CHAR(%d)', $length ?? 255);
     }
 
     /**
diff --git a/lib/Doctrine/DBAL/Platforms/SqlitePlatform.php b/lib/Doctrine/DBAL/Platforms/SqlitePlatform.php
index c33970fc142..e42a6bd89ec 100644
--- a/lib/Doctrine/DBAL/Platforms/SqlitePlatform.php
+++ b/lib/Doctrine/DBAL/Platforms/SqlitePlatform.php
@@ -719,7 +719,9 @@ protected function getPreAlterTableIndexForeignKeySQL(TableDiff $diff)
      */
     protected function getPostAlterTableIndexForeignKeySQL(TableDiff $diff)
     {
-        if (! $diff->fromTable instanceof Table) {
+        $fromTable = $diff->fromTable;
+
+        if (! $fromTable instanceof Table) {
             throw new Exception(
                 'Sqlite platform requires for alter table the table diff with reference to original table schema'
             );
@@ -732,7 +734,7 @@ protected function getPostAlterTableIndexForeignKeySQL(TableDiff $diff)
             $tableName = $diff->getName($this);
         }
 
-        foreach ($this->getIndexesInAlteredTable($diff) as $index) {
+        foreach ($this->getIndexesInAlteredTable($diff, $fromTable) as $index) {
             if ($index->isPrimary()) {
                 continue;
             }
@@ -952,8 +954,8 @@ public function getAlterTableSQL(TableDiff $diff)
             $newTable = new Table(
                 $table->getQuotedName($this),
                 $columns,
-                $this->getPrimaryIndexInAlteredTable($diff),
-                $this->getForeignKeysInAlteredTable($diff),
+                $this->getPrimaryIndexInAlteredTable($diff, $fromTable),
+                $this->getForeignKeysInAlteredTable($diff, $fromTable),
                 0,
                 $table->getOptions()
             );
@@ -1092,11 +1094,11 @@ private function getSimpleAlterTableSQL(TableDiff $diff)
     /**
      * @return string[]
      */
-    private function getColumnNamesInAlteredTable(TableDiff $diff)
+    private function getColumnNamesInAlteredTable(TableDiff $diff, Table $fromTable)
     {
         $columns = [];
 
-        foreach ($diff->fromTable->getColumns() as $columnName => $column) {
+        foreach ($fromTable->getColumns() as $columnName => $column) {
             $columns[strtolower($columnName)] = $column->getName();
         }
 
@@ -1132,10 +1134,10 @@ private function getColumnNamesInAlteredTable(TableDiff $diff)
     /**
      * @return Index[]
      */
-    private function getIndexesInAlteredTable(TableDiff $diff)
+    private function getIndexesInAlteredTable(TableDiff $diff, Table $fromTable)
     {
-        $indexes     = $diff->fromTable->getIndexes();
-        $columnNames = $this->getColumnNamesInAlteredTable($diff);
+        $indexes     = $fromTable->getIndexes();
+        $columnNames = $this->getColumnNamesInAlteredTable($diff, $fromTable);
 
         foreach ($indexes as $key => $index) {
             foreach ($diff->renamedIndexes as $oldIndexName => $renamedIndex) {
@@ -1200,10 +1202,10 @@ private function getIndexesInAlteredTable(TableDiff $diff)
     /**
      * @return ForeignKeyConstraint[]
      */
-    private function getForeignKeysInAlteredTable(TableDiff $diff)
+    private function getForeignKeysInAlteredTable(TableDiff $diff, Table $fromTable)
     {
-        $foreignKeys = $diff->fromTable->getForeignKeys();
-        $columnNames = $this->getColumnNamesInAlteredTable($diff);
+        $foreignKeys = $fromTable->getForeignKeys();
+        $columnNames = $this->getColumnNamesInAlteredTable($diff, $fromTable);
 
         foreach ($foreignKeys as $key => $constraint) {
             $changed      = false;
@@ -1264,11 +1266,11 @@ private function getForeignKeysInAlteredTable(TableDiff $diff)
     /**
      * @return Index[]
      */
-    private function getPrimaryIndexInAlteredTable(TableDiff $diff)
+    private function getPrimaryIndexInAlteredTable(TableDiff $diff, Table $fromTable)
     {
         $primaryIndex = [];
 
-        foreach ($this->getIndexesInAlteredTable($diff) as $index) {
+        foreach ($this->getIndexesInAlteredTable($diff, $fromTable) as $index) {
             if (! $index->isPrimary()) {
                 continue;
             }
diff --git a/lib/Doctrine/DBAL/Query/QueryBuilder.php b/lib/Doctrine/DBAL/Query/QueryBuilder.php
index c0c0ea58451..492a06951bb 100644
--- a/lib/Doctrine/DBAL/Query/QueryBuilder.php
+++ b/lib/Doctrine/DBAL/Query/QueryBuilder.php
@@ -119,14 +119,14 @@ class QueryBuilder
      *
      * @var int
      */
-    private $firstResult = null;
+    private $firstResult;
 
     /**
      * The maximum number of results to retrieve or NULL to retrieve all results.
      *
      * @var int|null
      */
-    private $maxResults = null;
+    private $maxResults;
 
     /**
      * The counter of bound parameters used with {@see bindValue).
diff --git a/lib/Doctrine/DBAL/Schema/AbstractAsset.php b/lib/Doctrine/DBAL/Schema/AbstractAsset.php
index 3424b17c544..02111832e26 100644
--- a/lib/Doctrine/DBAL/Schema/AbstractAsset.php
+++ b/lib/Doctrine/DBAL/Schema/AbstractAsset.php
@@ -31,7 +31,7 @@ abstract class AbstractAsset
      *
      * @var string|null
      */
-    protected $_namespace = null;
+    protected $_namespace;
 
     /** @var bool */
     protected $_quoted = false;
diff --git a/lib/Doctrine/DBAL/Schema/Column.php b/lib/Doctrine/DBAL/Schema/Column.php
index e33f285108b..f63bcc9226b 100644
--- a/lib/Doctrine/DBAL/Schema/Column.php
+++ b/lib/Doctrine/DBAL/Schema/Column.php
@@ -21,7 +21,7 @@ class Column extends AbstractAsset
     protected $_type;
 
     /** @var int|null */
-    protected $_length = null;
+    protected $_length;
 
     /** @var int */
     protected $_precision = 10;
@@ -39,7 +39,7 @@ class Column extends AbstractAsset
     protected $_notnull = true;
 
     /** @var string|null */
-    protected $_default = null;
+    protected $_default;
 
     /** @var bool */
     protected $_autoincrement = false;
@@ -48,10 +48,10 @@ class Column extends AbstractAsset
     protected $_platformOptions = [];
 
     /** @var string|null */
-    protected $_columnDefinition = null;
+    protected $_columnDefinition;
 
     /** @var string|null */
-    protected $_comment = null;
+    protected $_comment;
 
     /** @var mixed[] */
     protected $_customSchemaOptions = [];
diff --git a/lib/Doctrine/DBAL/Schema/DB2SchemaManager.php b/lib/Doctrine/DBAL/Schema/DB2SchemaManager.php
index 25f0282c536..fcc196ae519 100644
--- a/lib/Doctrine/DBAL/Schema/DB2SchemaManager.php
+++ b/lib/Doctrine/DBAL/Schema/DB2SchemaManager.php
@@ -7,7 +7,6 @@
 
 use function array_change_key_case;
 use function assert;
-use function is_resource;
 use function preg_match;
 use function str_replace;
 use function strpos;
@@ -207,13 +206,12 @@ protected function _getPortableForeignKeyRuleDef($def)
     protected function _getPortableViewDefinition($view)
     {
         $view = array_change_key_case($view, CASE_LOWER);
-        // sadly this still segfaults on PDO_IBM, see http://pecl.php.net/bugs/bug.php?id=17199
-        //$view['text'] = (is_resource($view['text']) ? stream_get_contents($view['text']) : $view['text']);
-        if (! is_resource($view['text'])) {
-            $pos = strpos($view['text'], ' AS ');
+
+        $sql = '';
+        $pos = strpos($view['text'], ' AS ');
+
+        if ($pos !== false) {
             $sql = substr($view['text'], $pos + 4);
-        } else {
-            $sql = '';
         }
 
         return new View($view['name'], $sql);
diff --git a/lib/Doctrine/DBAL/Schema/PostgreSqlSchemaManager.php b/lib/Doctrine/DBAL/Schema/PostgreSqlSchemaManager.php
index d9fabec1660..e64a9c81735 100644
--- a/lib/Doctrine/DBAL/Schema/PostgreSqlSchemaManager.php
+++ b/lib/Doctrine/DBAL/Schema/PostgreSqlSchemaManager.php
@@ -60,7 +60,11 @@ public function getSchemaNames()
     public function getSchemaSearchPaths()
     {
         $params = $this->_conn->getParams();
-        $schema = explode(',', $this->_conn->fetchColumn('SHOW search_path'));
+
+        $searchPaths = $this->_conn->fetchColumn('SHOW search_path');
+        assert($searchPaths !== false);
+
+        $schema = explode(',', $searchPaths);
 
         if (isset($params['user'])) {
             $schema = str_replace('"$user"', $params['user'], $schema);
@@ -150,13 +154,17 @@ protected function _getPortableTableForeignKeyDefinition($tableForeignKey)
             $onDelete = $match[1];
         }
 
-        if (preg_match('/FOREIGN KEY \((.+)\) REFERENCES (.+)\((.+)\)/', $tableForeignKey['condef'], $values)) {
-            // PostgreSQL returns identifiers that are keywords with quotes, we need them later, don't get
-            // the idea to trim them here.
-            $localColumns   = array_map('trim', explode(',', $values[1]));
-            $foreignColumns = array_map('trim', explode(',', $values[3]));
-            $foreignTable   = $values[2];
-        }
+        assert(preg_match(
+            '/FOREIGN KEY \((.+)\) REFERENCES (.+)\((.+)\)/',
+            $tableForeignKey['condef'],
+            $values
+        ) !== 0);
+
+        // PostgreSQL returns identifiers that are keywords with quotes, we need them later, don't get
+        // the idea to trim them here.
+        $localColumns   = array_map('trim', explode(',', $values[1]));
+        $foreignColumns = array_map('trim', explode(',', $values[3]));
+        $foreignTable   = $values[2];
 
         return new ForeignKeyConstraint(
             $localColumns,
diff --git a/lib/Doctrine/DBAL/Schema/Schema.php b/lib/Doctrine/DBAL/Schema/Schema.php
index 6ea5fd0c8c0..24fc47b599b 100644
--- a/lib/Doctrine/DBAL/Schema/Schema.php
+++ b/lib/Doctrine/DBAL/Schema/Schema.php
@@ -52,7 +52,7 @@ class Schema extends AbstractAsset
     protected $_sequences = [];
 
     /** @var SchemaConfig */
-    protected $_schemaConfig = false;
+    protected $_schemaConfig;
 
     /**
      * @param Table[]    $tables
diff --git a/lib/Doctrine/DBAL/Schema/Sequence.php b/lib/Doctrine/DBAL/Schema/Sequence.php
index 19dec9cd57a..1cba86c086c 100644
--- a/lib/Doctrine/DBAL/Schema/Sequence.php
+++ b/lib/Doctrine/DBAL/Schema/Sequence.php
@@ -19,7 +19,7 @@ class Sequence extends AbstractAsset
     protected $initialValue = 1;
 
     /** @var int|null */
-    protected $cache = null;
+    protected $cache;
 
     /**
      * @param string   $name
diff --git a/lib/Doctrine/DBAL/Schema/Table.php b/lib/Doctrine/DBAL/Schema/Table.php
index bd0462151a4..d69dc45f189 100644
--- a/lib/Doctrine/DBAL/Schema/Table.php
+++ b/lib/Doctrine/DBAL/Schema/Table.php
@@ -29,7 +29,7 @@ class Table extends AbstractAsset
     /** @var Index[] */
     protected $_indexes = [];
 
-    /** @var string */
+    /** @var string|false */
     protected $_primaryKeyName = false;
 
     /** @var ForeignKeyConstraint[] */
@@ -41,7 +41,7 @@ class Table extends AbstractAsset
     ];
 
     /** @var SchemaConfig|null */
-    protected $_schemaConfig = null;
+    protected $_schemaConfig;
 
     /**
      * @param string                 $name
@@ -150,6 +150,10 @@ public function addIndex(array $columnNames, $indexName = null, array $flags = [
      */
     public function dropPrimaryKey()
     {
+        if ($this->_primaryKeyName === false) {
+            return;
+        }
+
         $this->dropIndex($this->_primaryKeyName);
         $this->_primaryKeyName = false;
     }
@@ -717,11 +721,11 @@ public function getColumn($name)
      */
     public function getPrimaryKey()
     {
-        if (! $this->hasPrimaryKey()) {
-            return null;
+        if ($this->_primaryKeyName !== false) {
+            return $this->getIndex($this->_primaryKeyName);
         }
 
-        return $this->getIndex($this->_primaryKeyName);
+        return null;
     }
 
     /**
diff --git a/lib/Doctrine/DBAL/Schema/TableDiff.php b/lib/Doctrine/DBAL/Schema/TableDiff.php
index dcaeb200a6a..82c912f71b1 100644
--- a/lib/Doctrine/DBAL/Schema/TableDiff.php
+++ b/lib/Doctrine/DBAL/Schema/TableDiff.php
@@ -10,7 +10,7 @@
 class TableDiff
 {
     /** @var string */
-    public $name = null;
+    public $name;
 
     /** @var string|false */
     public $newName = false;
diff --git a/lib/Doctrine/DBAL/Schema/Visitor/CreateSchemaSqlCollector.php b/lib/Doctrine/DBAL/Schema/Visitor/CreateSchemaSqlCollector.php
index b2fab3ae4af..c08fb6fecd8 100644
--- a/lib/Doctrine/DBAL/Schema/Visitor/CreateSchemaSqlCollector.php
+++ b/lib/Doctrine/DBAL/Schema/Visitor/CreateSchemaSqlCollector.php
@@ -24,7 +24,7 @@ class CreateSchemaSqlCollector extends AbstractVisitor
     private $createFkConstraintQueries = [];
 
     /** @var AbstractPlatform */
-    private $platform = null;
+    private $platform;
 
     public function __construct(AbstractPlatform $platform)
     {
diff --git a/lib/Doctrine/DBAL/Sharding/SQLAzure/SQLAzureFederationsSynchronizer.php b/lib/Doctrine/DBAL/Sharding/SQLAzure/SQLAzureFederationsSynchronizer.php
index 7ea9ce1fad3..5fa2aa782eb 100644
--- a/lib/Doctrine/DBAL/Sharding/SQLAzure/SQLAzureFederationsSynchronizer.php
+++ b/lib/Doctrine/DBAL/Sharding/SQLAzure/SQLAzureFederationsSynchronizer.php
@@ -125,6 +125,8 @@ public function getDropAllSchema()
         $this->shardManager->selectGlobal();
         $globalSql = $this->synchronizer->getDropAllSchema();
 
+        $sql = [];
+
         if ($globalSql) {
             $sql[] = "-- Work on Root Federation\nUSE FEDERATION ROOT WITH RESET;";
             $sql   = array_merge($sql, $globalSql);
diff --git a/lib/Doctrine/DBAL/Tools/Console/Command/ImportCommand.php b/lib/Doctrine/DBAL/Tools/Console/Command/ImportCommand.php
index 3d53f342968..26456bde0ce 100644
--- a/lib/Doctrine/DBAL/Tools/Console/Command/ImportCommand.php
+++ b/lib/Doctrine/DBAL/Tools/Console/Command/ImportCommand.php
@@ -85,9 +85,14 @@ protected function execute(InputInterface $input, OutputInterface $output)
             $sql = @file_get_contents($filePath);
 
             if ($sql === false) {
-                throw new RuntimeException(
-                    sprintf("Unable to read SQL file '<info>%s</info>': %s", $filePath, error_get_last()['message'])
-                );
+                $message = sprintf("Unable to read SQL file '<info>%s</info>'", $filePath);
+                $error   = error_get_last();
+
+                if ($error !== null) {
+                    $message .= ': ' . $error['message'];
+                }
+
+                throw new RuntimeException($message);
             }
 
             if ($conn instanceof PDOConnection) {
diff --git a/lib/Doctrine/DBAL/Tools/Console/Command/ReservedWordsCommand.php b/lib/Doctrine/DBAL/Tools/Console/Command/ReservedWordsCommand.php
index 1888efdb619..bd819af0e6a 100644
--- a/lib/Doctrine/DBAL/Tools/Console/Command/ReservedWordsCommand.php
+++ b/lib/Doctrine/DBAL/Tools/Console/Command/ReservedWordsCommand.php
@@ -4,6 +4,7 @@
 
 use Doctrine\DBAL\Connection;
 use Doctrine\DBAL\Platforms\Keywords\DB2Keywords;
+use Doctrine\DBAL\Platforms\Keywords\KeywordList;
 use Doctrine\DBAL\Platforms\Keywords\MySQL57Keywords;
 use Doctrine\DBAL\Platforms\Keywords\MySQL80Keywords;
 use Doctrine\DBAL\Platforms\Keywords\MySQLKeywords;
@@ -41,7 +42,7 @@
 
 class ReservedWordsCommand extends Command
 {
-    /** @var string[] */
+    /** @var array<string,class-string<KeywordList>> */
     private $keywordListClasses = [
         'mysql'         => MySQLKeywords::class,
         'mysql57'       => MySQL57Keywords::class,
@@ -82,8 +83,8 @@ public function __construct(?ConnectionProvider $connectionProvider = null)
     /**
      * If you want to add or replace a keywords list use this command.
      *
-     * @param string $name
-     * @param string $class
+     * @param string                    $name
+     * @param class-string<KeywordList> $class
      *
      * @return void
      */
diff --git a/lib/Doctrine/DBAL/Types/Type.php b/lib/Doctrine/DBAL/Types/Type.php
index 5ff51c4c9bb..f8be9131bcd 100644
--- a/lib/Doctrine/DBAL/Types/Type.php
+++ b/lib/Doctrine/DBAL/Types/Type.php
@@ -236,8 +236,8 @@ public static function getType($name)
     /**
      * Adds a custom type to the type map.
      *
-     * @param string $name      The name of the type. This should correspond to what getName() returns.
-     * @param string $className The class name of the custom type.
+     * @param string             $name      The name of the type. This should correspond to what getName() returns.
+     * @param class-string<Type> $className The class name of the custom type.
      *
      * @return void
      *
@@ -263,8 +263,8 @@ public static function hasType($name)
     /**
      * Overrides an already defined type to use a different implementation.
      *
-     * @param string $name
-     * @param string $className
+     * @param string             $name
+     * @param class-string<Type> $className
      *
      * @return void
      *
diff --git a/psalm.xml b/psalm.xml
index f67b67c6566..999a5611126 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <psalm
     totallyTyped="false"
-    errorLevel="4"
+    errorLevel="3"
     resolveFromConfigFile="true"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="https://getpsalm.org/schema/config"
@@ -76,6 +76,12 @@
                 <file name="lib/Doctrine/DBAL/Driver/OCI8/OCI8Connection.php"/>
             </errorLevel>
         </ImplementedReturnTypeMismatch>
+        <InvalidPropertyAssignmentValue>
+            <errorLevel type="suppress">
+                <!-- Fixing this issue requires an API change -->
+                <file name="lib/Doctrine/DBAL/Driver/PDOException.php"/>
+            </errorLevel>
+        </InvalidPropertyAssignmentValue>
         <MethodSignatureMismatch>
             <errorLevel type="suppress">
                 <!--
@@ -93,6 +99,20 @@
                 <file name="lib/Doctrine/DBAL/Driver/AbstractSQLiteDriver.php"/>
             </errorLevel>
         </NullableReturnStatement>
+        <PossiblyInvalidOperand>
+            <errorLevel type="suppress">
+                <!--
+                    This code relies on certain elements of a mixed-type array to be of a certain type.
+                -->
+                <file name="lib/Doctrine/DBAL/SQLParserUtils.php"/>
+            </errorLevel>
+        </PossiblyInvalidOperand>
+        <PossiblyNullArgument>
+            <errorLevel type="suppress">
+                <!-- See https://github.com/doctrine/dbal/pull/3488 -->
+                <file name="lib/Doctrine/DBAL/Schema/AbstractSchemaManager.php"/>
+            </errorLevel>
+        </PossiblyNullArgument>
         <TooFewArguments>
             <errorLevel type="suppress">
                 <!--
diff --git a/tests/Doctrine/Tests/DBAL/ConnectionTest.php b/tests/Doctrine/Tests/DBAL/ConnectionTest.php
index 5543a42dec7..675881ac207 100644
--- a/tests/Doctrine/Tests/DBAL/ConnectionTest.php
+++ b/tests/Doctrine/Tests/DBAL/ConnectionTest.php
@@ -51,7 +51,7 @@ protected function setUp(): void
     }
 
     /**
-     * @return Connection|MockObject
+     * @return Connection&MockObject
      */
     private function getExecuteStatementMockConnection()
     {
@@ -648,22 +648,18 @@ public function testFetchAll(): void
 
     public function testConnectionDoesNotMaintainTwoReferencesToExternalPDO(): void
     {
-        $params['pdo'] = new stdClass();
-
         $driverMock = $this->createMock(Driver::class);
 
-        $conn = new Connection($params, $driverMock);
+        $conn = new Connection(['pdo' => new stdClass()], $driverMock);
 
         self::assertArrayNotHasKey('pdo', $conn->getParams());
     }
 
     public function testPassingExternalPDOMeansConnectionIsConnected(): void
     {
-        $params['pdo'] = new stdClass();
-
         $driverMock = $this->createMock(Driver::class);
 
-        $conn = new Connection($params, $driverMock);
+        $conn = new Connection(['pdo' => new stdClass()], $driverMock);
 
         self::assertTrue($conn->isConnected(), 'Connection is not connected after passing external PDO');
     }
diff --git a/tests/Doctrine/Tests/DBAL/Driver/AbstractDriverTest.php b/tests/Doctrine/Tests/DBAL/Driver/AbstractDriverTest.php
index 078875a4086..c08b33fb898 100644
--- a/tests/Doctrine/Tests/DBAL/Driver/AbstractDriverTest.php
+++ b/tests/Doctrine/Tests/DBAL/Driver/AbstractDriverTest.php
@@ -70,7 +70,8 @@ protected function setUp(): void
     }
 
     /**
-     * @param int|string $errorCode
+     * @param int|string                    $errorCode
+     * @param class-string<DriverException> $expectedClass
      *
      * @dataProvider exceptionConversionProvider
      */
diff --git a/tests/Doctrine/Tests/DBAL/Driver/IBMDB2/DB2ConnectionTest.php b/tests/Doctrine/Tests/DBAL/Driver/IBMDB2/DB2ConnectionTest.php
index e8b08f745e5..1d7d88ec342 100644
--- a/tests/Doctrine/Tests/DBAL/Driver/IBMDB2/DB2ConnectionTest.php
+++ b/tests/Doctrine/Tests/DBAL/Driver/IBMDB2/DB2ConnectionTest.php
@@ -14,7 +14,7 @@ class DB2ConnectionTest extends DbalTestCase
     /**
      * The ibm_db2 driver connection mock under test.
      *
-     * @var DB2Connection|MockObject
+     * @var DB2Connection&MockObject
      */
     private $connectionMock;
 
diff --git a/tests/Doctrine/Tests/DBAL/Driver/Mysqli/MysqliConnectionTest.php b/tests/Doctrine/Tests/DBAL/Driver/Mysqli/MysqliConnectionTest.php
index 9611da063cd..c0953ea532b 100644
--- a/tests/Doctrine/Tests/DBAL/Driver/Mysqli/MysqliConnectionTest.php
+++ b/tests/Doctrine/Tests/DBAL/Driver/Mysqli/MysqliConnectionTest.php
@@ -19,7 +19,7 @@ class MysqliConnectionTest extends DbalFunctionalTestCase
     /**
      * The mysqli driver connection mock under test.
      *
-     * @var MysqliConnection|MockObject
+     * @var MysqliConnection&MockObject
      */
     private $connectionMock;
 
diff --git a/tests/Doctrine/Tests/DBAL/Driver/OCI8/OCI8ConnectionTest.php b/tests/Doctrine/Tests/DBAL/Driver/OCI8/OCI8ConnectionTest.php
index 12cd8ef7af4..5185f4abc10 100644
--- a/tests/Doctrine/Tests/DBAL/Driver/OCI8/OCI8ConnectionTest.php
+++ b/tests/Doctrine/Tests/DBAL/Driver/OCI8/OCI8ConnectionTest.php
@@ -14,7 +14,7 @@ class OCI8ConnectionTest extends DbalTestCase
     /**
      * The oci8 driver connection mock under test.
      *
-     * @var OCI8Connection|MockObject
+     * @var OCI8Connection&MockObject
      */
     private $connectionMock;
 
diff --git a/tests/Doctrine/Tests/DBAL/Driver/PDO/ExceptionTest.php b/tests/Doctrine/Tests/DBAL/Driver/PDO/ExceptionTest.php
index 4ba493ab2ee..f9323041038 100644
--- a/tests/Doctrine/Tests/DBAL/Driver/PDO/ExceptionTest.php
+++ b/tests/Doctrine/Tests/DBAL/Driver/PDO/ExceptionTest.php
@@ -5,7 +5,6 @@
 use Doctrine\DBAL\Driver\PDO\Exception;
 use Doctrine\Tests\DbalTestCase;
 use PDOException;
-use PHPUnit\Framework\MockObject\MockObject;
 
 /**
  * @requires extension pdo
@@ -28,7 +27,7 @@ class ExceptionTest extends DbalTestCase
     /**
      * The wrapped PDO exception mock.
      *
-     * @var PDOException|MockObject
+     * @var PDOException
      */
     private $wrappedException;
 
diff --git a/tests/Doctrine/Tests/DBAL/Driver/PDOPgSql/DriverTest.php b/tests/Doctrine/Tests/DBAL/Driver/PDOPgSql/DriverTest.php
index 4a7044594f3..bfef87d5de4 100644
--- a/tests/Doctrine/Tests/DBAL/Driver/PDOPgSql/DriverTest.php
+++ b/tests/Doctrine/Tests/DBAL/Driver/PDOPgSql/DriverTest.php
@@ -84,11 +84,15 @@ private function connect(array $driverOptions): Connection
     {
         $params = TestUtil::getConnectionParams();
 
-        return $this->createDriver()->connect(
+        $connection = $this->createDriver()->connect(
             $params,
             $params['user'] ?? '',
             $params['password'] ?? '',
             $driverOptions
         );
+
+        self::assertInstanceOf(Connection::class, $connection);
+
+        return $connection;
     }
 }
diff --git a/tests/Doctrine/Tests/DBAL/Driver/SQLAnywhere/SQLAnywhereConnectionTest.php b/tests/Doctrine/Tests/DBAL/Driver/SQLAnywhere/SQLAnywhereConnectionTest.php
index b2d1ddef6fc..54cedfce3cd 100644
--- a/tests/Doctrine/Tests/DBAL/Driver/SQLAnywhere/SQLAnywhereConnectionTest.php
+++ b/tests/Doctrine/Tests/DBAL/Driver/SQLAnywhere/SQLAnywhereConnectionTest.php
@@ -14,7 +14,7 @@ class SQLAnywhereConnectionTest extends DbalTestCase
     /**
      * The sqlanywhere driver connection mock under test.
      *
-     * @var SQLAnywhereConnection|MockObject
+     * @var SQLAnywhereConnection&MockObject
      */
     private $connectionMock;
 
diff --git a/tests/Doctrine/Tests/DBAL/Driver/SQLSrv/SQLSrvConnectionTest.php b/tests/Doctrine/Tests/DBAL/Driver/SQLSrv/SQLSrvConnectionTest.php
index 8d424ee21b6..75781443962 100644
--- a/tests/Doctrine/Tests/DBAL/Driver/SQLSrv/SQLSrvConnectionTest.php
+++ b/tests/Doctrine/Tests/DBAL/Driver/SQLSrv/SQLSrvConnectionTest.php
@@ -11,7 +11,7 @@ class SQLSrvConnectionTest extends DbalTestCase
     /**
      * The sqlsrv driver connection mock under test.
      *
-     * @var SQLSrvConnection|MockObject
+     * @var SQLSrvConnection&MockObject
      */
     private $connectionMock;
 
diff --git a/tests/Doctrine/Tests/DBAL/Functional/DataAccessTest.php b/tests/Doctrine/Tests/DBAL/Functional/DataAccessTest.php
index ef68b5be62f..58322e9d90e 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/DataAccessTest.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/DataAccessTest.php
@@ -20,13 +20,13 @@
 use Doctrine\DBAL\Types\Types;
 use Doctrine\Tests\DbalFunctionalTestCase;
 use PDO;
+use stdClass;
 
 use function array_change_key_case;
 use function array_filter;
 use function array_keys;
 use function count;
 use function date;
-use function implode;
 use function is_numeric;
 use function json_encode;
 use function property_exists;
@@ -34,7 +34,6 @@
 use function strtotime;
 
 use const CASE_LOWER;
-use const PHP_EOL;
 
 class DataAccessTest extends DbalFunctionalTestCase
 {
@@ -361,6 +360,7 @@ public function testFetchArray(): void
     {
         $sql = 'SELECT test_int, test_string FROM fetch_table WHERE test_int = ? AND test_string = ?';
         $row = $this->connection->fetchArray($sql, [1, 'foo']);
+        self::assertNotFalse($row);
 
         self::assertEquals(1, $row[0]);
         self::assertEquals('foo', $row[1]);
@@ -505,6 +505,8 @@ public function testTrimExpression(string $value, int $position, $char, string $
             'FROM fetch_table';
 
         $row = $this->connection->fetchAssoc($sql);
+        self::assertNotFalse($row);
+
         $row = array_change_key_case($row, CASE_LOWER);
 
         self::assertEquals($expectedResult, $row['trimmed']);
@@ -578,6 +580,8 @@ public function testDateArithmetics(): void
         $sql .= 'FROM fetch_table';
 
         $row = $this->connection->fetchAssoc($sql);
+        self::assertNotFalse($row);
+
         $row = array_change_key_case($row, CASE_LOWER);
 
         self::assertEquals('2010-01-01 10:10:11', date('Y-m-d H:i:s', strtotime($row['add_seconds'])));
@@ -642,6 +646,8 @@ public function testLocateExpression(): void
         $sql .= 'FROM fetch_table';
 
         $row = $this->connection->fetchAssoc($sql);
+        self::assertNotFalse($row);
+
         $row = array_change_key_case($row, CASE_LOWER);
 
         self::assertEquals(2, $row['locate1']);
@@ -681,14 +687,20 @@ public function testBitComparisonExpressionSupport(): void
             ]);
         }
 
-        $sql[] = 'SELECT ';
-        $sql[] = 'test_int, ';
-        $sql[] = 'test_string, ';
-        $sql[] = $platform->getBitOrComparisonExpression('test_int', 2) . ' AS bit_or, ';
-        $sql[] = $platform->getBitAndComparisonExpression('test_int', 2) . ' AS bit_and ';
-        $sql[] = 'FROM fetch_table';
+        $sql = sprintf(
+            <<<'SQL'
+SELECT test_int,
+       test_string,
+       %s AS bit_or,
+       %s AS bit_and
+FROM   fetch_table
+SQL
+            ,
+            $platform->getBitOrComparisonExpression('test_int', 2),
+            $platform->getBitAndComparisonExpression('test_int', 2)
+        );
 
-        $stmt = $this->connection->executeQuery(implode(PHP_EOL, $sql));
+        $stmt = $this->connection->executeQuery($sql);
         $data = $stmt->fetchAll(FetchMode::ASSOCIATIVE);
 
         self::assertCount(4, $data);
@@ -734,7 +746,7 @@ public function testFetchAllStyleObject(): void
         $results = $stmt->fetchAll(FetchMode::STANDARD_OBJECT);
 
         self::assertCount(1, $results);
-        self::assertInstanceOf('stdClass', $results[0]);
+        self::assertInstanceOf(stdClass::class, $results[0]);
 
         self::assertEquals(
             1,
diff --git a/tests/Doctrine/Tests/DBAL/Functional/Driver/OCI8/ConnectionTest.php b/tests/Doctrine/Tests/DBAL/Functional/Driver/OCI8/ConnectionTest.php
index f4947212ec0..909528eb06e 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/Driver/OCI8/ConnectionTest.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/Driver/OCI8/ConnectionTest.php
@@ -2,7 +2,6 @@
 
 namespace Doctrine\Tests\DBAL\Functional\Driver\OCI8;
 
-use Doctrine\DBAL\Driver\OCI8\Connection;
 use Doctrine\DBAL\Driver\OCI8\Driver;
 use Doctrine\DBAL\Schema\Table;
 use Doctrine\Tests\DbalFunctionalTestCase;
@@ -12,18 +11,15 @@
  */
 class ConnectionTest extends DbalFunctionalTestCase
 {
-    /** @var Connection */
-    protected $driverConnection;
-
     protected function setUp(): void
     {
         parent::setUp();
 
-        if (! $this->connection->getDriver() instanceof Driver) {
-            $this->markTestSkipped('oci8 only test.');
+        if ($this->connection->getDriver() instanceof Driver) {
+            return;
         }
 
-        $this->driverConnection = $this->connection->getWrappedConnection();
+        $this->markTestSkipped('oci8 only test.');
     }
 
     public function testLastInsertIdAcceptsFqn(): void
@@ -42,6 +38,6 @@ public function testLastInsertIdAcceptsFqn(): void
         $schema   = $this->connection->getDatabase();
         $sequence = $platform->getIdentitySequenceName($schema . '.DBAL2595', 'id');
 
-        self::assertSame(1, $this->driverConnection->lastInsertId($sequence));
+        self::assertSame(1, $this->connection->lastInsertId($sequence));
     }
 }
diff --git a/tests/Doctrine/Tests/DBAL/Functional/Driver/PDO/ConnectionTest.php b/tests/Doctrine/Tests/DBAL/Functional/Driver/PDO/ConnectionTest.php
index c9f748fbce6..143cbf6c687 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/Driver/PDO/ConnectionTest.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/Driver/PDO/ConnectionTest.php
@@ -31,13 +31,13 @@ protected function setUp(): void
     {
         parent::setUp();
 
-        $this->driverConnection = $this->connection->getWrappedConnection();
+        $driverConnection = $this->connection->getWrappedConnection();
 
-        if ($this->driverConnection instanceof Connection) {
-            return;
+        if (! $driverConnection instanceof Connection) {
+            $this->markTestSkipped('PDO connection only test.');
         }
 
-        $this->markTestSkipped('PDO connection only test.');
+        $this->driverConnection = $driverConnection;
     }
 
     protected function tearDown(): void
diff --git a/tests/Doctrine/Tests/DBAL/Functional/Driver/PDOSqlsrv/DriverTest.php b/tests/Doctrine/Tests/DBAL/Functional/Driver/PDOSqlsrv/DriverTest.php
index d829a013ea7..f8974ef7b14 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/Driver/PDOSqlsrv/DriverTest.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/Driver/PDOSqlsrv/DriverTest.php
@@ -48,12 +48,16 @@ private function getConnection(array $driverOptions): Connection
             $driverOptions = array_merge($params['driverOptions'], $driverOptions);
         }
 
-        return $this->connection->getDriver()->connect(
+        $connection = $this->connection->getDriver()->connect(
             $params,
             $params['user'] ?? '',
             $params['password'] ?? '',
             $driverOptions
         );
+
+        self::assertInstanceOf(Connection::class, $connection);
+
+        return $connection;
     }
 
     public function testConnectionOptions(): void
diff --git a/tests/Doctrine/Tests/DBAL/Functional/MasterSlaveConnectionTest.php b/tests/Doctrine/Tests/DBAL/Functional/MasterSlaveConnectionTest.php
index 13aaea3c6a9..5e75f6fd29d 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/MasterSlaveConnectionTest.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/MasterSlaveConnectionTest.php
@@ -11,9 +11,6 @@
 
 use function array_change_key_case;
 use function sprintf;
-use function strlen;
-use function strtolower;
-use function substr;
 
 use const CASE_LOWER;
 
@@ -46,7 +43,11 @@ protected function setUp(): void
 
     private function createMasterSlaveConnection(bool $keepSlave = false): MasterSlaveConnection
     {
-        return DriverManager::getConnection($this->createMasterSlaveConnectionParams($keepSlave));
+        $connection = DriverManager::getConnection($this->createMasterSlaveConnectionParams($keepSlave));
+
+        self::assertInstanceOf(MasterSlaveConnection::class, $connection);
+
+        return $connection;
     }
 
     /**
@@ -88,12 +89,9 @@ public function testInheritCharsetFromMaster(): void
 
             self::assertFalse($conn->isConnectedToMaster());
 
-            $clientCharset = $conn->fetchColumn('select @@character_set_client as c');
+            $clientCharset = $conn->fetchColumn('select @@character_set_client');
 
-            self::assertSame(
-                $charset,
-                substr(strtolower($clientCharset), 0, strlen($charset))
-            );
+            self::assertSame($charset, $clientCharset);
         }
     }
 
diff --git a/tests/Doctrine/Tests/DBAL/Functional/PrimaryReadReplicaConnectionTest.php b/tests/Doctrine/Tests/DBAL/Functional/PrimaryReadReplicaConnectionTest.php
index 7dd14c355ee..e371cf2cfeb 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/PrimaryReadReplicaConnectionTest.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/PrimaryReadReplicaConnectionTest.php
@@ -11,9 +11,6 @@
 
 use function array_change_key_case;
 use function sprintf;
-use function strlen;
-use function strtolower;
-use function substr;
 
 use const CASE_LOWER;
 
@@ -49,7 +46,11 @@ protected function setUp(): void
 
     private function createPrimaryReadReplicaConnection(bool $keepReplica = false): PrimaryReadReplicaConnection
     {
-        return DriverManager::getConnection($this->createPrimaryReadReplicaConnectionParams($keepReplica));
+        $connection = DriverManager::getConnection($this->createPrimaryReadReplicaConnectionParams($keepReplica));
+
+        self::assertInstanceOf(PrimaryReadReplicaConnection::class, $connection);
+
+        return $connection;
     }
 
     /**
@@ -93,10 +94,7 @@ public function testInheritCharsetFromPrimary(): void
 
             $clientCharset = $conn->fetchColumn('select @@character_set_client as c');
 
-            self::assertSame(
-                $charset,
-                substr(strtolower($clientCharset), 0, strlen($charset))
-            );
+            self::assertSame($charset, $clientCharset);
         }
     }
 
diff --git a/tests/Doctrine/Tests/DBAL/Functional/Schema/MySqlSchemaManagerTest.php b/tests/Doctrine/Tests/DBAL/Functional/Schema/MySqlSchemaManagerTest.php
index 1da8e4dbfaa..0b1e56daebc 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/Schema/MySqlSchemaManagerTest.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/Schema/MySqlSchemaManagerTest.php
@@ -45,8 +45,10 @@ public function testSwitchPrimaryKeyColumns(): void
         $tableNew     = clone $tableFetched;
         $tableNew->setPrimaryKey(['bar_id', 'foo_id']);
 
-        $comparator = new Comparator();
-        $this->schemaManager->alterTable($comparator->diffTable($tableFetched, $tableNew));
+        $diff = (new Comparator())->diffTable($tableFetched, $tableNew);
+        self::assertNotFalse($diff);
+
+        $this->schemaManager->alterTable($diff);
 
         $table      = $this->schemaManager->listTableDetails('switch_primary_key_columns');
         $primaryKey = $table->getPrimaryKeyColumns();
@@ -73,8 +75,7 @@ public function testDiffTableBug(): void
         $this->schemaManager->createTable($table);
         $tableFetched = $this->schemaManager->listTableDetails('diffbug_routing_translations');
 
-        $comparator = new Comparator();
-        $diff       = $comparator->diffTable($tableFetched, $table);
+        $diff = (new Comparator())->diffTable($tableFetched, $table);
 
         self::assertFalse($diff, 'no changes expected.');
     }
@@ -135,13 +136,15 @@ public function testAlterTableAddPrimaryKey(): void
 
         $this->schemaManager->createTable($table);
 
-        $comparator = new Comparator();
-        $diffTable  = clone $table;
+        $diffTable = clone $table;
 
         $diffTable->dropIndex('idx_id');
         $diffTable->setPrimaryKey(['id']);
 
-        $this->schemaManager->alterTable($comparator->diffTable($table, $diffTable));
+        $diff = (new Comparator())->diffTable($table, $diffTable);
+        self::assertNotFalse($diff);
+
+        $this->schemaManager->alterTable($diff);
 
         $table = $this->schemaManager->listTableDetails('alter_table_add_pk');
 
@@ -162,9 +165,10 @@ public function testDropPrimaryKeyWithAutoincrementColumn(): void
 
         $diffTable->dropPrimaryKey();
 
-        $comparator = new Comparator();
+        $diff = (new Comparator())->diffTable($table, $diffTable);
+        self::assertNotFalse($diff);
 
-        $this->schemaManager->alterTable($comparator->diffTable($table, $diffTable));
+        $this->schemaManager->alterTable($diff);
 
         $table = $this->schemaManager->listTableDetails('drop_primary_key');
 
@@ -197,9 +201,10 @@ public function testDoesNotPropagateDefaultValuesForUnsupportedColumnTypes(): vo
         self::assertNull($onlineTable->getColumn('def_blob_null')->getDefault());
         self::assertFalse($onlineTable->getColumn('def_blob_null')->getNotnull());
 
-        $comparator = new Comparator();
+        $diff = (new Comparator())->diffTable($table, $onlineTable);
+        self::assertNotFalse($diff);
 
-        $this->schemaManager->alterTable($comparator->diffTable($table, $onlineTable));
+        $this->schemaManager->alterTable($diff);
 
         $onlineTable = $this->schemaManager->listTableDetails('text_blob_default_value');
 
@@ -240,9 +245,10 @@ public function testAlterColumnCharset(): void
         $diffTable = clone $table;
         $diffTable->getColumn('col_text')->setPlatformOption('charset', 'ascii');
 
-        $comparator = new Comparator();
+        $diff = (new Comparator())->diffTable($table, $diffTable);
+        self::assertNotFalse($diff);
 
-        $this->schemaManager->alterTable($comparator->diffTable($table, $diffTable));
+        $this->schemaManager->alterTable($diff);
 
         $table = $this->schemaManager->listTableDetails($tableName);
 
@@ -457,6 +463,7 @@ public function testColumnDefaultsAreValid(): void
         $row = $this->connection->fetchAssoc(
             'SELECT *, DATEDIFF(CURRENT_TIMESTAMP(), col_datetime) as diff_seconds FROM test_column_defaults_are_valid'
         );
+        self::assertNotFalse($row);
 
         self::assertInstanceOf(DateTime::class, DateTime::createFromFormat('Y-m-d H:i:s', $row['col_datetime']));
         self::assertNull($row['col_datetime_null']);
diff --git a/tests/Doctrine/Tests/DBAL/Functional/Schema/OracleSchemaManagerTest.php b/tests/Doctrine/Tests/DBAL/Functional/Schema/OracleSchemaManagerTest.php
index d39b7373216..af0c6b79791 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/Schema/OracleSchemaManagerTest.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/Schema/OracleSchemaManagerTest.php
@@ -5,6 +5,7 @@
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Platforms\OraclePlatform;
 use Doctrine\DBAL\Schema;
+use Doctrine\DBAL\Schema\Comparator;
 use Doctrine\DBAL\Schema\Table;
 use Doctrine\DBAL\Types\BinaryType;
 use Doctrine\DBAL\Types\Types;
@@ -76,9 +77,8 @@ public function testListTableWithBinary(): void
 
     public function testAlterTableColumnNotNull(): void
     {
-        $comparator = new Schema\Comparator();
-        $tableName  = 'list_table_column_notnull';
-        $table      = new Schema\Table($tableName);
+        $tableName = 'list_table_column_notnull';
+        $table     = new Table($tableName);
 
         $table->addColumn('id', 'integer');
         $table->addColumn('foo', 'integer');
@@ -97,7 +97,10 @@ public function testAlterTableColumnNotNull(): void
         $diffTable->changeColumn('foo', ['notnull' => false]);
         $diffTable->changeColumn('bar', ['length' => 1024]);
 
-        $this->schemaManager->alterTable($comparator->diffTable($table, $diffTable));
+        $diff = (new Comparator())->diffTable($table, $diffTable);
+        self::assertNotFalse($diff);
+
+        $this->schemaManager->alterTable($diff);
 
         $columns = $this->schemaManager->listTableColumns($tableName);
 
@@ -122,7 +125,7 @@ public function testListDatabases(): void
     public function testListTableDetailsWithDifferentIdentifierQuotingRequirements(): void
     {
         $primaryTableName    = '"Primary_Table"';
-        $offlinePrimaryTable = new Schema\Table($primaryTableName);
+        $offlinePrimaryTable = new Table($primaryTableName);
         $offlinePrimaryTable->addColumn(
             '"Id"',
             'integer',
@@ -139,7 +142,7 @@ public function testListTableDetailsWithDifferentIdentifierQuotingRequirements()
         $offlinePrimaryTable->setPrimaryKey(['"Id"']);
 
         $foreignTableName    = 'foreign';
-        $offlineForeignTable = new Schema\Table($foreignTableName);
+        $offlineForeignTable = new Table($foreignTableName);
         $offlineForeignTable->addColumn('id', 'integer', ['autoincrement' => true]);
         $offlineForeignTable->addColumn('"Fk"', 'integer');
         $offlineForeignTable->addIndex(['"Fk"'], '"Fk_index"');
@@ -169,7 +172,11 @@ public function testListTableDetailsWithDifferentIdentifierQuotingRequirements()
         self::assertTrue($onlinePrimaryTable->hasColumn('"Id"'));
         self::assertSame('"Id"', $onlinePrimaryTable->getColumn('"Id"')->getQuotedName($platform));
         self::assertTrue($onlinePrimaryTable->hasPrimaryKey());
-        self::assertSame(['"Id"'], $onlinePrimaryTable->getPrimaryKey()->getQuotedColumns($platform));
+
+        $primaryKey = $onlinePrimaryTable->getPrimaryKey();
+
+        self::assertNotNull($primaryKey);
+        self::assertSame(['"Id"'], $primaryKey->getQuotedColumns($platform));
 
         self::assertTrue($onlinePrimaryTable->hasColumn('select'));
         self::assertSame('"select"', $onlinePrimaryTable->getColumn('select')->getQuotedName($platform));
@@ -203,7 +210,11 @@ public function testListTableDetailsWithDifferentIdentifierQuotingRequirements()
         self::assertTrue($onlineForeignTable->hasColumn('id'));
         self::assertSame('ID', $onlineForeignTable->getColumn('id')->getQuotedName($platform));
         self::assertTrue($onlineForeignTable->hasPrimaryKey());
-        self::assertSame(['ID'], $onlineForeignTable->getPrimaryKey()->getQuotedColumns($platform));
+
+        $primaryKey = $onlineForeignTable->getPrimaryKey();
+
+        self::assertNotNull($primaryKey);
+        self::assertSame(['ID'], $primaryKey->getQuotedColumns($platform));
 
         self::assertTrue($onlineForeignTable->hasColumn('"Fk"'));
         self::assertSame('"Fk"', $onlineForeignTable->getColumn('"Fk"')->getQuotedName($platform));
diff --git a/tests/Doctrine/Tests/DBAL/Functional/Schema/PostgreSqlSchemaManagerTest.php b/tests/Doctrine/Tests/DBAL/Functional/Schema/PostgreSqlSchemaManagerTest.php
index aadf78a8b48..949ee50d51c 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/Schema/PostgreSqlSchemaManagerTest.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/Schema/PostgreSqlSchemaManagerTest.php
@@ -99,9 +99,10 @@ public function testAlterTableAutoIncrementAdd(): void
         $column  = $tableTo->addColumn('id', 'integer');
         $column->setAutoincrement(true);
 
-        $c    = new Comparator();
-        $diff = $c->diffTable($tableFrom, $tableTo);
-        $sql  = $this->connection->getDatabasePlatform()->getAlterTableSQL($diff);
+        $diff = (new Comparator())->diffTable($tableFrom, $tableTo);
+        self::assertNotFalse($diff);
+
+        $sql = $this->connection->getDatabasePlatform()->getAlterTableSQL($diff);
         self::assertEquals([
             'CREATE SEQUENCE autoinc_table_add_id_seq',
             "SELECT setval('autoinc_table_add_id_seq', (SELECT MAX(id) FROM autoinc_table_add))",
@@ -125,9 +126,9 @@ public function testAlterTableAutoIncrementDrop(): void
         $tableTo = new Table('autoinc_table_drop');
         $tableTo->addColumn('id', 'integer');
 
-        $c    = new Comparator();
-        $diff = $c->diffTable($tableFrom, $tableTo);
-        self::assertInstanceOf(TableDiff::class, $diff);
+        $diff = (new Comparator())->diffTable($tableFrom, $tableTo);
+        self::assertNotFalse($diff);
+
         self::assertEquals(
             ['ALTER TABLE autoinc_table_drop ALTER id DROP DEFAULT'],
             $this->connection->getDatabasePlatform()->getAlterTableSQL($diff)
@@ -161,7 +162,11 @@ public function testTableWithSchema(): void
 
         $nestedSchemaTable = $this->schemaManager->listTableDetails('nested.schematable');
         self::assertTrue($nestedSchemaTable->hasColumn('id'));
-        self::assertEquals(['id'], $nestedSchemaTable->getPrimaryKey()->getColumns());
+
+        $primaryKey = $nestedSchemaTable->getPrimaryKey();
+
+        self::assertNotNull($primaryKey);
+        self::assertEquals(['id'], $primaryKey->getColumns());
 
         $relatedFks = $nestedSchemaTable->getForeignKeys();
         self::assertCount(1, $relatedFks);
diff --git a/tests/Doctrine/Tests/DBAL/Functional/Schema/SchemaManagerFunctionalTestCase.php b/tests/Doctrine/Tests/DBAL/Functional/Schema/SchemaManagerFunctionalTestCase.php
index 8ae88a87738..a635991e998 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/Schema/SchemaManagerFunctionalTestCase.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/Schema/SchemaManagerFunctionalTestCase.php
@@ -741,10 +741,10 @@ public function testUpdateSchemaWithForeignKeyRenaming(): void
         $tableFKNew->addIndex(['rename_fk_id'], 'fk_idx');
         $tableFKNew->addForeignKeyConstraint('test_fk_base', ['rename_fk_id'], ['id']);
 
-        $c         = new Comparator();
-        $tableDiff = $c->diffTable($tableFK, $tableFKNew);
+        $diff = (new Comparator())->diffTable($tableFK, $tableFKNew);
+        self::assertNotFalse($diff);
 
-        $this->schemaManager->alterTable($tableDiff);
+        $this->schemaManager->alterTable($diff);
 
         $table       = $this->schemaManager->listTableDetails('test_fk_rename');
         $foreignKeys = $table->getForeignKeys();
@@ -781,9 +781,10 @@ public function testRenameIndexUsedInForeignKeyConstraint(): void
         $foreignTable2 = clone $foreignTable;
         $foreignTable2->renameIndex('rename_index_fk_idx', 'renamed_index_fk_idx');
 
-        $comparator = new Comparator();
+        $diff = (new Comparator())->diffTable($foreignTable, $foreignTable2);
+        self::assertNotFalse($diff);
 
-        $this->schemaManager->alterTable($comparator->diffTable($foreignTable, $foreignTable2));
+        $this->schemaManager->alterTable($diff);
 
         $foreignTable = $this->schemaManager->listTableDetails('test_rename_index_foreign');
 
@@ -958,7 +959,7 @@ protected function createTestTable(string $name = 'test_table', array $data = []
      */
     protected function getTestTable(string $name, array $options = []): Table
     {
-        $table = new Table($name, [], [], [], false, $options);
+        $table = new Table($name, [], [], [], 0, $options);
         $table->setSchemaConfig($this->schemaManager->createSchemaConfig());
         $table->addColumn('id', 'integer', ['notnull' => true]);
         $table->setPrimaryKey(['id']);
@@ -970,7 +971,7 @@ protected function getTestTable(string $name, array $options = []): Table
 
     protected function getTestCompositeTable(string $name): Table
     {
-        $table = new Table($name, [], [], [], false, []);
+        $table = new Table($name, [], [], [], 0, []);
         $table->setSchemaConfig($this->schemaManager->createSchemaConfig());
         $table->addColumn('id', 'integer', ['notnull' => true]);
         $table->addColumn('other_id', 'integer', ['notnull' => true]);
@@ -1061,9 +1062,10 @@ public function testColumnDefaultLifecycle(): void
         $diffTable->changeColumn('column6', ['default' => 666]);
         $diffTable->changeColumn('column7', ['default' => null]);
 
-        $comparator = new Comparator();
+        $diff = (new Comparator())->diffTable($table, $diffTable);
+        self::assertNotFalse($diff);
 
-        $this->schemaManager->alterTable($comparator->diffTable($table, $diffTable));
+        $this->schemaManager->alterTable($diff);
 
         $columns = $this->schemaManager->listTableColumns('col_def_lifecycle');
 
diff --git a/tests/Doctrine/Tests/DBAL/Functional/Schema/SqliteSchemaManagerTest.php b/tests/Doctrine/Tests/DBAL/Functional/Schema/SqliteSchemaManagerTest.php
index dc46c35a0f3..b7c0c606fa4 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/Schema/SqliteSchemaManagerTest.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/Schema/SqliteSchemaManagerTest.php
@@ -7,6 +7,7 @@
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Platforms\SqlitePlatform;
 use Doctrine\DBAL\Schema;
+use Doctrine\DBAL\Schema\Comparator;
 use Doctrine\DBAL\Schema\Table;
 use Doctrine\DBAL\Types\BlobType;
 use Doctrine\DBAL\Types\Type;
@@ -203,10 +204,11 @@ public function testDiffListIntegerAutoincrementTableColumns(
         $this->schemaManager->dropAndCreateTable($offlineTable);
 
         $onlineTable = $this->schemaManager->listTableDetails($tableName);
-        $comparator  = new Schema\Comparator();
-        $diff        = $comparator->diffTable($offlineTable, $onlineTable);
+
+        $diff = (new Comparator())->diffTable($offlineTable, $onlineTable);
 
         if ($expectedComparatorDiff) {
+            self::assertNotFalse($diff);
             self::assertEmpty($this->schemaManager->getDatabasePlatform()->getAlterTableSQL($diff));
         } else {
             self::assertFalse($diff);
diff --git a/tests/Doctrine/Tests/DBAL/Functional/Ticket/DBAL421Test.php b/tests/Doctrine/Tests/DBAL/Functional/Ticket/DBAL421Test.php
index 35e9f0675bc..7bd3dd42333 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/Ticket/DBAL421Test.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/Ticket/DBAL421Test.php
@@ -23,7 +23,9 @@ protected function setUp(): void
 
     public function testGuidShouldMatchPattern(): void
     {
-        $guid    = $this->connection->query($this->getSelectGuidSql())->fetchColumn();
+        $guid = $this->connection->query($this->getSelectGuidSql())->fetchColumn();
+        self::assertNotFalse($guid);
+
         $pattern = '/[0-9A-F]{8}\-[0-9A-F]{4}\-[0-9A-F]{4}\-[8-9A-B][0-9A-F]{3}\-[0-9A-F]{12}/i';
         self::assertEquals(1, preg_match($pattern, $guid), 'GUID does not match pattern');
     }
diff --git a/tests/Doctrine/Tests/DBAL/Functional/Ticket/DBAL630Test.php b/tests/Doctrine/Tests/DBAL/Functional/Ticket/DBAL630Test.php
index 77cd108b595..dea9f88d8f6 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/Ticket/DBAL630Test.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/Ticket/DBAL630Test.php
@@ -50,6 +50,7 @@ public function testBooleanConversionSqlLiteral(): void
         self::assertNotEmpty($id);
 
         $row = $this->connection->fetchAssoc('SELECT bool_col FROM dbal630 WHERE id = ?', [$id]);
+        self::assertNotFalse($row);
 
         self::assertFalse($row['bool_col']);
     }
@@ -65,6 +66,7 @@ public function testBooleanConversionBoolParamRealPrepares(): void
         self::assertNotEmpty($id);
 
         $row = $this->connection->fetchAssoc('SELECT bool_col FROM dbal630 WHERE id = ?', [$id]);
+        self::assertNotFalse($row);
 
         self::assertFalse($row['bool_col']);
     }
@@ -84,6 +86,7 @@ public function testBooleanConversionBoolParamEmulatedPrepares(): void
         self::assertNotEmpty($id);
 
         $row = $this->connection->fetchAssoc('SELECT bool_col FROM dbal630 WHERE id = ?', [$id]);
+        self::assertNotFalse($row);
 
         self::assertFalse($row['bool_col']);
     }
@@ -108,6 +111,7 @@ public function testBooleanConversionNullParamEmulatedPrepares(
         self::assertNotEmpty($id);
 
         $row = $this->connection->fetchAssoc('SELECT bool_col FROM dbal630_allow_nulls WHERE id = ?', [$id]);
+        self::assertNotFalse($row);
 
         self::assertSame($databaseConvertedValue, $row['bool_col']);
     }
@@ -136,6 +140,7 @@ public function testBooleanConversionNullParamEmulatedPreparesWithBooleanTypeInB
         self::assertNotEmpty($id);
 
         $row = $this->connection->fetchAssoc('SELECT bool_col FROM dbal630_allow_nulls WHERE id = ?', [$id]);
+        self::assertNotFalse($row);
 
         self::assertSame($databaseConvertedValue, $row['bool_col']);
     }
diff --git a/tests/Doctrine/Tests/DBAL/Platforms/AbstractMySQLPlatformTestCase.php b/tests/Doctrine/Tests/DBAL/Platforms/AbstractMySQLPlatformTestCase.php
index 984e19ec719..6f47275a4e8 100644
--- a/tests/Doctrine/Tests/DBAL/Platforms/AbstractMySQLPlatformTestCase.php
+++ b/tests/Doctrine/Tests/DBAL/Platforms/AbstractMySQLPlatformTestCase.php
@@ -184,8 +184,8 @@ public function testUniquePrimaryKey(): void
         $oldTable->addColumn('bar', 'integer');
         $oldTable->addColumn('baz', 'string');
 
-        $c    = new Comparator();
-        $diff = $c->diffTable($oldTable, $keyTable);
+        $diff = (new Comparator())->diffTable($oldTable, $keyTable);
+        self::assertNotFalse($diff);
 
         $sql = $this->platform->getAlterTableSQL($diff);
 
@@ -384,15 +384,17 @@ public function testAlterTableAddPrimaryKey(): void
         $table->addColumn('foo', 'integer');
         $table->addIndex(['id'], 'idx_id');
 
-        $comparator = new Comparator();
-        $diffTable  = clone $table;
+        $diffTable = clone $table;
 
         $diffTable->dropIndex('idx_id');
         $diffTable->setPrimaryKey(['id']);
 
+        $diff = (new Comparator())->diffTable($table, $diffTable);
+        self::assertNotFalse($diff);
+
         self::assertEquals(
             ['DROP INDEX idx_id ON alter_table_add_pk', 'ALTER TABLE alter_table_add_pk ADD PRIMARY KEY (id)'],
-            $this->platform->getAlterTableSQL($comparator->diffTable($table, $diffTable))
+            $this->platform->getAlterTableSQL($diff)
         );
     }
 
@@ -403,19 +405,21 @@ public function testAlterPrimaryKeyWithAutoincrementColumn(): void
         $table->addColumn('foo', 'integer');
         $table->setPrimaryKey(['id']);
 
-        $comparator = new Comparator();
-        $diffTable  = clone $table;
+        $diffTable = clone $table;
 
         $diffTable->dropPrimaryKey();
         $diffTable->setPrimaryKey(['foo']);
 
+        $diff = (new Comparator())->diffTable($table, $diffTable);
+        self::assertNotFalse($diff);
+
         self::assertEquals(
             [
                 'ALTER TABLE alter_primary_key MODIFY id INT NOT NULL',
                 'ALTER TABLE alter_primary_key DROP PRIMARY KEY',
                 'ALTER TABLE alter_primary_key ADD PRIMARY KEY (foo)',
             ],
-            $this->platform->getAlterTableSQL($comparator->diffTable($table, $diffTable))
+            $this->platform->getAlterTableSQL($diff)
         );
     }
 
@@ -427,17 +431,19 @@ public function testDropPrimaryKeyWithAutoincrementColumn(): void
         $table->addColumn('bar', 'integer');
         $table->setPrimaryKey(['id', 'foo']);
 
-        $comparator = new Comparator();
-        $diffTable  = clone $table;
+        $diffTable = clone $table;
 
         $diffTable->dropPrimaryKey();
 
+        $diff = (new Comparator())->diffTable($table, $diffTable);
+        self::assertNotFalse($diff);
+
         self::assertEquals(
             [
                 'ALTER TABLE drop_primary_key MODIFY id INT NOT NULL',
                 'ALTER TABLE drop_primary_key DROP PRIMARY KEY',
             ],
-            $this->platform->getAlterTableSQL($comparator->diffTable($table, $diffTable))
+            $this->platform->getAlterTableSQL($diff)
         );
     }
 
@@ -449,19 +455,21 @@ public function testDropNonAutoincrementColumnFromCompositePrimaryKeyWithAutoinc
         $table->addColumn('bar', 'integer');
         $table->setPrimaryKey(['id', 'foo']);
 
-        $comparator = new Comparator();
-        $diffTable  = clone $table;
+        $diffTable = clone $table;
 
         $diffTable->dropPrimaryKey();
         $diffTable->setPrimaryKey(['id']);
 
+        $diff = (new Comparator())->diffTable($table, $diffTable);
+        self::assertNotFalse($diff);
+
         self::assertSame(
             [
                 'ALTER TABLE tbl MODIFY id INT NOT NULL',
                 'ALTER TABLE tbl DROP PRIMARY KEY',
                 'ALTER TABLE tbl ADD PRIMARY KEY (id)',
             ],
-            $this->platform->getAlterTableSQL($comparator->diffTable($table, $diffTable))
+            $this->platform->getAlterTableSQL($diff)
         );
     }
 
@@ -473,19 +481,21 @@ public function testAddNonAutoincrementColumnToPrimaryKeyWithAutoincrementColumn
         $table->addColumn('bar', 'integer');
         $table->setPrimaryKey(['id']);
 
-        $comparator = new Comparator();
-        $diffTable  = clone $table;
+        $diffTable = clone $table;
 
         $diffTable->dropPrimaryKey();
         $diffTable->setPrimaryKey(['id', 'foo']);
 
+        $diff = (new Comparator())->diffTable($table, $diffTable);
+        self::assertNotFalse($diff);
+
         self::assertSame(
             [
                 'ALTER TABLE tbl MODIFY id INT NOT NULL',
                 'ALTER TABLE tbl DROP PRIMARY KEY',
                 'ALTER TABLE tbl ADD PRIMARY KEY (id, foo)',
             ],
-            $this->platform->getAlterTableSQL($comparator->diffTable($table, $diffTable))
+            $this->platform->getAlterTableSQL($diff)
         );
     }
 
@@ -499,8 +509,8 @@ public function testAddAutoIncrementPrimaryKey(): void
         $oldTable = new Table('foo');
         $oldTable->addColumn('baz', 'string');
 
-        $c    = new Comparator();
-        $diff = $c->diffTable($oldTable, $keyTable);
+        $diff = (new Comparator())->diffTable($oldTable, $keyTable);
+        self::assertNotFalse($diff);
 
         $sql = $this->platform->getAlterTableSQL($diff);
 
@@ -527,20 +537,22 @@ public function testAlterPrimaryKeyWithNewColumn(): void
         $table->addColumn('col_a', 'integer');
         $table->setPrimaryKey(['pkc1']);
 
-        $comparator = new Comparator();
-        $diffTable  = clone $table;
+        $diffTable = clone $table;
 
         $diffTable->addColumn('pkc2', 'integer');
         $diffTable->dropPrimaryKey();
         $diffTable->setPrimaryKey(['pkc1', 'pkc2']);
 
+        $diff = (new Comparator())->diffTable($table, $diffTable);
+        self::assertNotFalse($diff);
+
         self::assertSame(
             [
                 'ALTER TABLE yolo DROP PRIMARY KEY',
                 'ALTER TABLE yolo ADD pkc2 INT NOT NULL',
                 'ALTER TABLE yolo ADD PRIMARY KEY (pkc1, pkc2)',
             ],
-            $this->platform->getAlterTableSQL($comparator->diffTable($table, $diffTable))
+            $this->platform->getAlterTableSQL($diff)
         );
     }
 
@@ -757,9 +769,10 @@ public function testDoesNotPropagateDefaultValuesForUnsupportedColumnTypes(): vo
         $diffTable->changeColumn('def_blob', ['default' => null]);
         $diffTable->changeColumn('def_blob_null', ['default' => null]);
 
-        $comparator = new Comparator();
+        $diff = (new Comparator())->diffTable($table, $diffTable);
+        self::assertNotFalse($diff);
 
-        self::assertEmpty($this->platform->getAlterTableSQL($comparator->diffTable($table, $diffTable)));
+        self::assertEmpty($this->platform->getAlterTableSQL($diff));
     }
 
     /**
diff --git a/tests/Doctrine/Tests/DBAL/Platforms/AbstractPlatformTestCase.php b/tests/Doctrine/Tests/DBAL/Platforms/AbstractPlatformTestCase.php
index 9ef99d6d416..658839bd8c1 100644
--- a/tests/Doctrine/Tests/DBAL/Platforms/AbstractPlatformTestCase.php
+++ b/tests/Doctrine/Tests/DBAL/Platforms/AbstractPlatformTestCase.php
@@ -950,11 +950,12 @@ public function testQuotesAlterTableRenameColumn(): void
         // quoted -> quoted
         $toTable->addColumn('`baz`', 'integer', ['comment' => 'Quoted 3']);
 
-        $comparator = new Comparator();
+        $diff = (new Comparator())->diffTable($fromTable, $toTable);
+        self::assertNotFalse($diff);
 
         self::assertEquals(
             $this->getQuotedAlterTableRenameColumnSQL(),
-            $this->platform->getAlterTableSQL($comparator->diffTable($fromTable, $toTable))
+            $this->platform->getAlterTableSQL($diff)
         );
     }
 
@@ -987,11 +988,12 @@ public function testQuotesAlterTableChangeColumnLength(): void
         $toTable->addColumn('table', 'string', ['comment' => 'Reserved keyword 2', 'length' => 255]);
         $toTable->addColumn('select', 'string', ['comment' => 'Reserved keyword 3', 'length' => 255]);
 
-        $comparator = new Comparator();
+        $diff = (new Comparator())->diffTable($fromTable, $toTable);
+        self::assertNotFalse($diff);
 
         self::assertEquals(
             $this->getQuotedAlterTableChangeColumnLengthSQL(),
-            $this->platform->getAlterTableSQL($comparator->diffTable($fromTable, $toTable))
+            $this->platform->getAlterTableSQL($diff)
         );
     }
 
@@ -1159,7 +1161,7 @@ public function testGetCommentOnColumnSQL(): void
     /**
      * @dataProvider getGeneratesInlineColumnCommentSQL
      */
-    public function testGeneratesInlineColumnCommentSQL(?string $comment, string $expectedSql): void
+    public function testGeneratesInlineColumnCommentSQL(string $comment, string $expectedSql): void
     {
         if (! $this->platform->supportsInlineColumnComments()) {
             $this->markTestSkipped(sprintf('%s does not support inline column comments.', get_class($this->platform)));
diff --git a/tests/Doctrine/Tests/DBAL/Platforms/AbstractPostgreSqlPlatformTestCase.php b/tests/Doctrine/Tests/DBAL/Platforms/AbstractPostgreSqlPlatformTestCase.php
index 5adf73f7aa0..184dcbb216c 100644
--- a/tests/Doctrine/Tests/DBAL/Platforms/AbstractPostgreSqlPlatformTestCase.php
+++ b/tests/Doctrine/Tests/DBAL/Platforms/AbstractPostgreSqlPlatformTestCase.php
@@ -600,10 +600,10 @@ public function testDroppingConstraintsBeforeColumns(): void
         $oldTable->addColumn('parent_id', 'integer');
         $oldTable->addUnnamedForeignKeyConstraint('mytable', ['parent_id'], ['id']);
 
-        $comparator = new Comparator();
-        $tableDiff  = $comparator->diffTable($oldTable, $newTable);
+        $diff = (new Comparator())->diffTable($oldTable, $newTable);
+        self::assertNotFalse($diff);
 
-        $sql = $this->platform->getAlterTableSQL($tableDiff);
+        $sql = $this->platform->getAlterTableSQL($diff);
 
         $expectedSql = [
             'ALTER TABLE mytable DROP CONSTRAINT FK_6B2BD609727ACA70',
@@ -681,7 +681,9 @@ public function testDoesNotPropagateUnnecessaryTableAlterationOnBinaryType(): vo
         // VARBINARY -> BINARY
         // BINARY    -> VARBINARY
         // BLOB      -> VARBINARY
-        self::assertEmpty($this->platform->getAlterTableSQL($comparator->diffTable($table1, $table2)));
+        $diff = $comparator->diffTable($table1, $table2);
+        self::assertNotFalse($diff);
+        self::assertEmpty($this->platform->getAlterTableSQL($diff));
 
         $table2 = new Table('mytable');
         $table2->addColumn('column_varbinary', 'binary', ['length' => 42]);
@@ -691,7 +693,9 @@ public function testDoesNotPropagateUnnecessaryTableAlterationOnBinaryType(): vo
         // VARBINARY -> VARBINARY with changed length
         // BINARY    -> BLOB
         // BLOB      -> BINARY
-        self::assertEmpty($this->platform->getAlterTableSQL($comparator->diffTable($table1, $table2)));
+        $diff = $comparator->diffTable($table1, $table2);
+        self::assertNotFalse($diff);
+        self::assertEmpty($this->platform->getAlterTableSQL($diff));
 
         $table2 = new Table('mytable');
         $table2->addColumn('column_varbinary', 'blob');
@@ -701,7 +705,9 @@ public function testDoesNotPropagateUnnecessaryTableAlterationOnBinaryType(): vo
         // VARBINARY -> BLOB
         // BINARY    -> BINARY with changed length
         // BLOB      -> BLOB
-        self::assertEmpty($this->platform->getAlterTableSQL($comparator->diffTable($table1, $table2)));
+        $diff = $comparator->diffTable($table1, $table2);
+        self::assertNotFalse($diff);
+        self::assertEmpty($this->platform->getAlterTableSQL($diff));
     }
 
     /**
@@ -887,7 +893,7 @@ public function testAltersTableColumnCommentIfRequiredByType(): void
 
         $tableDiff = $comparator->diffTable($table1, $table2);
 
-        $this->assertInstanceOf('Doctrine\DBAL\Schema\TableDiff', $tableDiff);
+        $this->assertNotFalse($tableDiff);
         $this->assertSame(
             [
                 'ALTER TABLE "foo" ALTER "bar" TYPE TIMESTAMP(0) WITHOUT TIME ZONE',
diff --git a/tests/Doctrine/Tests/DBAL/Platforms/OraclePlatformTest.php b/tests/Doctrine/Tests/DBAL/Platforms/OraclePlatformTest.php
index 9cd147026b1..11ca8e60f96 100644
--- a/tests/Doctrine/Tests/DBAL/Platforms/OraclePlatformTest.php
+++ b/tests/Doctrine/Tests/DBAL/Platforms/OraclePlatformTest.php
@@ -582,7 +582,9 @@ public function testDoesNotPropagateUnnecessaryTableAlterationOnBinaryType(): vo
 
         // VARBINARY -> BINARY
         // BINARY    -> VARBINARY
-        self::assertEmpty($this->platform->getAlterTableSQL($comparator->diffTable($table1, $table2)));
+        $diff = (new Comparator())->diffTable($table1, $table2);
+        self::assertNotFalse($diff);
+        self::assertEmpty($this->platform->getAlterTableSQL($diff));
     }
 
     public function testUsesSequenceEmulatedIdentityColumns(): void
diff --git a/tests/Doctrine/Tests/DBAL/Portability/StatementTest.php b/tests/Doctrine/Tests/DBAL/Portability/StatementTest.php
index f41124a8334..f83ab92e50d 100644
--- a/tests/Doctrine/Tests/DBAL/Portability/StatementTest.php
+++ b/tests/Doctrine/Tests/DBAL/Portability/StatementTest.php
@@ -15,13 +15,13 @@
 
 class StatementTest extends DbalTestCase
 {
-    /** @var Connection|MockObject */
+    /** @var Connection&MockObject */
     protected $conn;
 
     /** @var Statement */
     protected $stmt;
 
-    /** @var DriverStatement|MockObject */
+    /** @var DriverStatement&MockObject */
     protected $wrappedStmt;
 
     protected function setUp(): void
@@ -157,7 +157,7 @@ public function testRowCount(): void
     }
 
     /**
-     * @return Connection|MockObject
+     * @return Connection&MockObject
      */
     protected function createConnection()
     {
diff --git a/tests/Doctrine/Tests/DBAL/Schema/ComparatorTest.php b/tests/Doctrine/Tests/DBAL/Schema/ComparatorTest.php
index df2874a535a..9079fbec518 100644
--- a/tests/Doctrine/Tests/DBAL/Schema/ComparatorTest.php
+++ b/tests/Doctrine/Tests/DBAL/Schema/ComparatorTest.php
@@ -252,8 +252,8 @@ public function testCompareChangeColumnsMultipleNewColumnsRename(): void
         $tableB->addColumn('new_datecolumn1', 'datetime');
         $tableB->addColumn('new_datecolumn2', 'datetime');
 
-        $c         = new Comparator();
-        $tableDiff = $c->diffTable($tableA, $tableB);
+        $tableDiff = (new Comparator())->diffTable($tableA, $tableB);
+        self::assertNotFalse($tableDiff);
 
         self::assertCount(1, $tableDiff->renamedColumns);
         self::assertArrayHasKey('datecolumn1', $tableDiff->renamedColumns);
@@ -720,8 +720,8 @@ public function testDetectRenameColumn(): void
         $tableB = new Table('foo');
         $tableB->addColumn('bar', 'integer');
 
-        $c         = new Comparator();
-        $tableDiff = $c->diffTable($tableA, $tableB);
+        $tableDiff = (new Comparator())->diffTable($tableA, $tableB);
+        self::assertNotFalse($tableDiff);
 
         self::assertCount(0, $tableDiff->addedColumns);
         self::assertCount(0, $tableDiff->removedColumns);
@@ -743,8 +743,8 @@ public function testDetectRenameColumnAmbiguous(): void
         $tableB = new Table('foo');
         $tableB->addColumn('baz', 'integer');
 
-        $c         = new Comparator();
-        $tableDiff = $c->diffTable($tableA, $tableB);
+        $tableDiff = (new Comparator())->diffTable($tableA, $tableB);
+        self::assertNotFalse($tableDiff);
 
         self::assertCount(1, $tableDiff->addedColumns);
         self::assertArrayHasKey('baz', $tableDiff->addedColumns);
@@ -765,8 +765,8 @@ public function testDetectRenameIndex(): void
 
         $table2->addIndex(['foo'], 'idx_bar');
 
-        $comparator = new Comparator();
-        $tableDiff  = $comparator->diffTable($table1, $table2);
+        $tableDiff = (new Comparator())->diffTable($table1, $table2);
+        self::assertNotFalse($tableDiff);
 
         self::assertCount(0, $tableDiff->addedIndexes);
         self::assertCount(0, $tableDiff->removedIndexes);
@@ -791,8 +791,8 @@ public function testDetectRenameIndexAmbiguous(): void
 
         $table2->addIndex(['foo'], 'idx_baz');
 
-        $comparator = new Comparator();
-        $tableDiff  = $comparator->diffTable($table1, $table2);
+        $tableDiff = (new Comparator())->diffTable($table1, $table2);
+        self::assertNotFalse($tableDiff);
 
         self::assertCount(1, $tableDiff->addedIndexes);
         self::assertArrayHasKey('idx_baz', $tableDiff->addedIndexes);
diff --git a/tests/Doctrine/Tests/DBAL/Schema/DB2SchemaManagerTest.php b/tests/Doctrine/Tests/DBAL/Schema/DB2SchemaManagerTest.php
index faa784a6137..36b0551d338 100644
--- a/tests/Doctrine/Tests/DBAL/Schema/DB2SchemaManagerTest.php
+++ b/tests/Doctrine/Tests/DBAL/Schema/DB2SchemaManagerTest.php
@@ -18,7 +18,7 @@
  */
 final class DB2SchemaManagerTest extends TestCase
 {
-    /** @var Connection|MockObject */
+    /** @var Connection&MockObject */
     private $conn;
 
     /** @var DB2SchemaManager */
diff --git a/tests/Doctrine/Tests/DBAL/Schema/Platforms/MySQLSchemaTest.php b/tests/Doctrine/Tests/DBAL/Schema/Platforms/MySQLSchemaTest.php
index 3802ff27a01..d134a1f2f56 100644
--- a/tests/Doctrine/Tests/DBAL/Schema/Platforms/MySQLSchemaTest.php
+++ b/tests/Doctrine/Tests/DBAL/Schema/Platforms/MySQLSchemaTest.php
@@ -33,7 +33,9 @@ public function testSwitchPrimaryKeyOrder(): void
         $tableNew->setPrimaryKey(['bar_id', 'foo_id']);
 
         $diff = $this->comparator->diffTable($tableOld, $tableNew);
-        $sql  = $this->platform->getAlterTableSQL($diff);
+        self::assertNotFalse($diff);
+
+        $sql = $this->platform->getAlterTableSQL($diff);
 
         self::assertEquals(
             [
@@ -74,7 +76,9 @@ public function testClobNoAlterTable(): void
         $tableNew->setPrimaryKey(['id']);
 
         $diff = $this->comparator->diffTable($tableOld, $tableNew);
-        $sql  = $this->platform->getAlterTableSQL($diff);
+        self::assertNotFalse($diff);
+
+        $sql = $this->platform->getAlterTableSQL($diff);
 
         self::assertEquals(
             ['ALTER TABLE test ADD PRIMARY KEY (id)'],
diff --git a/tests/Doctrine/Tests/DBAL/Schema/SchemaDiffTest.php b/tests/Doctrine/Tests/DBAL/Schema/SchemaDiffTest.php
index 414d779438e..f5100e6c856 100644
--- a/tests/Doctrine/Tests/DBAL/Schema/SchemaDiffTest.php
+++ b/tests/Doctrine/Tests/DBAL/Schema/SchemaDiffTest.php
@@ -46,7 +46,7 @@ public function testSchemaDiffToSaveSql(): void
     }
 
     /**
-     * @return AbstractPlatform|MockObject
+     * @return AbstractPlatform&MockObject
      */
     private function createPlatform(bool $unsafe)
     {
diff --git a/tests/Doctrine/Tests/DBAL/Schema/TableDiffTest.php b/tests/Doctrine/Tests/DBAL/Schema/TableDiffTest.php
index 4c0ada138d0..c1b9ede62cb 100644
--- a/tests/Doctrine/Tests/DBAL/Schema/TableDiffTest.php
+++ b/tests/Doctrine/Tests/DBAL/Schema/TableDiffTest.php
@@ -11,7 +11,7 @@
 
 class TableDiffTest extends TestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     public function setUp(): void
diff --git a/tests/Doctrine/Tests/DBAL/Schema/TableTest.php b/tests/Doctrine/Tests/DBAL/Schema/TableTest.php
index c596fecfc9c..5b6d897aa80 100644
--- a/tests/Doctrine/Tests/DBAL/Schema/TableTest.php
+++ b/tests/Doctrine/Tests/DBAL/Schema/TableTest.php
@@ -210,7 +210,7 @@ public function testConstraints(): void
 
     public function testOptions(): void
     {
-        $table = new Table('foo', [], [], [], false, ['foo' => 'bar']);
+        $table = new Table('foo', [], [], [], 0, ['foo' => 'bar']);
 
         self::assertTrue($table->hasOption('foo'));
         self::assertEquals('bar', $table->getOption('foo'));
diff --git a/tests/Doctrine/Tests/DBAL/Schema/Visitor/CreateSchemaSqlCollectorTest.php b/tests/Doctrine/Tests/DBAL/Schema/Visitor/CreateSchemaSqlCollectorTest.php
index c4e1aca9e85..26354adef9d 100644
--- a/tests/Doctrine/Tests/DBAL/Schema/Visitor/CreateSchemaSqlCollectorTest.php
+++ b/tests/Doctrine/Tests/DBAL/Schema/Visitor/CreateSchemaSqlCollectorTest.php
@@ -12,7 +12,7 @@
 
 class CreateSchemaSqlCollectorTest extends TestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platformMock;
 
     /** @var CreateSchemaSqlCollector */
@@ -134,7 +134,7 @@ public function testResetsQueries(): void
     }
 
     /**
-     * @return ForeignKeyConstraint|MockObject
+     * @return ForeignKeyConstraint&MockObject
      */
     private function createForeignKeyConstraintMock()
     {
@@ -144,7 +144,7 @@ private function createForeignKeyConstraintMock()
     }
 
     /**
-     * @return Sequence|MockObject
+     * @return Sequence&MockObject
      */
     private function createSequenceMock()
     {
@@ -154,7 +154,7 @@ private function createSequenceMock()
     }
 
     /**
-     * @return Table|MockObject
+     * @return Table&MockObject
      */
     private function createTableMock()
     {
diff --git a/tests/Doctrine/Tests/DBAL/Sharding/SQLAzure/AbstractTestCase.php b/tests/Doctrine/Tests/DBAL/Sharding/SQLAzure/AbstractTestCase.php
index 8ad29bfcef6..3ab0991a519 100644
--- a/tests/Doctrine/Tests/DBAL/Sharding/SQLAzure/AbstractTestCase.php
+++ b/tests/Doctrine/Tests/DBAL/Sharding/SQLAzure/AbstractTestCase.php
@@ -41,6 +41,7 @@ protected function setUp(): void
         $this->conn = DriverManager::getConnection($params);
 
         $serverEdition = $this->conn->fetchColumn("SELECT CONVERT(NVARCHAR(128), SERVERPROPERTY('Edition'))");
+        self::assertNotFalse($serverEdition);
 
         if (strpos($serverEdition, 'SQL Azure') !== 0) {
             $this->markTestSkipped('SQL Azure only test.');
diff --git a/tests/Doctrine/Tests/DBAL/Sharding/SQLAzure/MultiTenantVisitorTest.php b/tests/Doctrine/Tests/DBAL/Sharding/SQLAzure/MultiTenantVisitorTest.php
index f12379fafee..560181996e3 100644
--- a/tests/Doctrine/Tests/DBAL/Sharding/SQLAzure/MultiTenantVisitorTest.php
+++ b/tests/Doctrine/Tests/DBAL/Sharding/SQLAzure/MultiTenantVisitorTest.php
@@ -2,7 +2,6 @@
 
 namespace Doctrine\Tests\DBAL\Sharding\SQLAzure;
 
-use Doctrine\DBAL\Platforms\SQLAzurePlatform;
 use Doctrine\DBAL\Schema\Schema;
 use Doctrine\DBAL\Sharding\SQLAzure\Schema\MultiTenantVisitor;
 use PHPUnit\Framework\TestCase;
@@ -11,8 +10,7 @@ class MultiTenantVisitorTest extends TestCase
 {
     public function testMultiTenantPrimaryKey(): void
     {
-        $platform = new SQLAzurePlatform();
-        $visitor  = new MultiTenantVisitor();
+        $visitor = new MultiTenantVisitor();
 
         $schema = new Schema();
         $foo    = $schema->createTable('foo');
@@ -20,14 +18,16 @@ public function testMultiTenantPrimaryKey(): void
         $foo->setPrimaryKey(['id']);
         $schema->visit($visitor);
 
-        self::assertEquals(['id', 'tenant_id'], $foo->getPrimaryKey()->getColumns());
+        $primaryKey = $foo->getPrimaryKey();
+
+        self::assertNotNull($primaryKey);
+        self::assertEquals(['id', 'tenant_id'], $primaryKey->getColumns());
         self::assertTrue($foo->hasColumn('tenant_id'));
     }
 
     public function testMultiTenantNonPrimaryKey(): void
     {
-        $platform = new SQLAzurePlatform();
-        $visitor  = new MultiTenantVisitor();
+        $visitor = new MultiTenantVisitor();
 
         $schema = new Schema();
         $foo    = $schema->createTable('foo');
@@ -36,12 +36,20 @@ public function testMultiTenantNonPrimaryKey(): void
         $foo->setPrimaryKey(['id']);
         $foo->addIndex(['created'], 'idx');
 
-        $foo->getPrimaryKey()->addFlag('nonclustered');
+        $primaryKey = $foo->getPrimaryKey();
+
+        self::assertNotNull($primaryKey);
+
+        $primaryKey->addFlag('nonclustered');
         $foo->getIndex('idx')->addFlag('clustered');
 
         $schema->visit($visitor);
 
-        self::assertEquals(['id'], $foo->getPrimaryKey()->getColumns());
+        $primaryKey = $foo->getPrimaryKey();
+
+        self::assertNotNull($primaryKey);
+
+        self::assertEquals(['id'], $primaryKey->getColumns());
         self::assertTrue($foo->hasColumn('tenant_id'));
         self::assertEquals(['created', 'tenant_id'], $foo->getIndex('idx')->getColumns());
     }
diff --git a/tests/Doctrine/Tests/DBAL/Tools/Console/RunSqlCommandTest.php b/tests/Doctrine/Tests/DBAL/Tools/Console/RunSqlCommandTest.php
index 8a99dd366b8..5b7357b30b1 100644
--- a/tests/Doctrine/Tests/DBAL/Tools/Console/RunSqlCommandTest.php
+++ b/tests/Doctrine/Tests/DBAL/Tools/Console/RunSqlCommandTest.php
@@ -24,16 +24,17 @@ class RunSqlCommandTest extends TestCase
 
     protected function setUp(): void
     {
-        $application = new Application();
-        $application->add(new RunSqlCommand());
+        $this->command = new RunSqlCommand();
 
-        $this->command       = $application->find('dbal:run-sql');
-        $this->commandTester = new CommandTester($this->command);
+        (new Application())->add($this->command);
 
         $this->connectionMock = $this->createMock(Connection::class);
 
         $helperSet = ConsoleRunner::createHelperSet($this->connectionMock);
+
         $this->command->setHelperSet($helperSet);
+
+        $this->commandTester = new CommandTester($this->command);
     }
 
     public function testMissingSqlArgument(): void
diff --git a/tests/Doctrine/Tests/DBAL/Tools/DumperTest.php b/tests/Doctrine/Tests/DBAL/Tools/DumperTest.php
index 53af4ae420a..5c64ae77834 100644
--- a/tests/Doctrine/Tests/DBAL/Tools/DumperTest.php
+++ b/tests/Doctrine/Tests/DBAL/Tools/DumperTest.php
@@ -14,10 +14,6 @@
 use Doctrine\Tests\DbalTestCase;
 use stdClass;
 
-use function print_r;
-use function strpos;
-use function substr;
-
 class DumperTest extends DbalTestCase
 {
     public function testExportObject(): void
@@ -99,14 +95,6 @@ public function testExportArrayTraversable(): void
      */
     public function testExportParentAttributes(TestAsset\ParentClass $class, array $expected): void
     {
-        $print_r_class    = print_r($class, true);
-        $print_r_expected = print_r($expected, true);
-
-        $print_r_class    = substr($print_r_class, strpos($print_r_class, '('));
-        $print_r_expected = substr($print_r_expected, strpos($print_r_expected, '('));
-
-        self::assertSame($print_r_class, $print_r_expected);
-
         $var = Dumper::export($class, 3);
         $var = (array) $var;
         unset($var['__CLASS__']);
diff --git a/tests/Doctrine/Tests/DBAL/Types/ArrayTest.php b/tests/Doctrine/Tests/DBAL/Types/ArrayTest.php
index df48f2f14b3..ebda9c37c2e 100644
--- a/tests/Doctrine/Tests/DBAL/Types/ArrayTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/ArrayTest.php
@@ -5,7 +5,6 @@
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\ArrayType;
 use Doctrine\DBAL\Types\ConversionException;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 
@@ -13,7 +12,7 @@
 
 class ArrayTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var ArrayType */
@@ -22,7 +21,7 @@ class ArrayTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('array');
+        $this->type     = new ArrayType();
     }
 
     public function testArrayConvertsToDatabaseValue(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/BaseDateTypeTestCase.php b/tests/Doctrine/Tests/DBAL/Types/BaseDateTypeTestCase.php
index b748cdf19a2..ee111fab030 100644
--- a/tests/Doctrine/Tests/DBAL/Types/BaseDateTypeTestCase.php
+++ b/tests/Doctrine/Tests/DBAL/Types/BaseDateTypeTestCase.php
@@ -16,7 +16,7 @@
 
 abstract class BaseDateTypeTestCase extends TestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     protected $platform;
 
     /** @var Type */
diff --git a/tests/Doctrine/Tests/DBAL/Types/BinaryTest.php b/tests/Doctrine/Tests/DBAL/Types/BinaryTest.php
index 23514f6160b..e1b14679c5b 100644
--- a/tests/Doctrine/Tests/DBAL/Types/BinaryTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/BinaryTest.php
@@ -6,7 +6,6 @@
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\BinaryType;
 use Doctrine\DBAL\Types\ConversionException;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\DBAL\Types\Types;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
@@ -17,7 +16,7 @@
 
 class BinaryTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     protected $platform;
 
     /** @var BinaryType */
@@ -26,7 +25,7 @@ class BinaryTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('binary');
+        $this->type     = new BinaryType();
     }
 
     public function testReturnsBindingType(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/BlobTest.php b/tests/Doctrine/Tests/DBAL/Types/BlobTest.php
index 23486819798..340608fff44 100644
--- a/tests/Doctrine/Tests/DBAL/Types/BlobTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/BlobTest.php
@@ -4,7 +4,6 @@
 
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\BlobType;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 
@@ -15,7 +14,7 @@
 
 class BlobTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     protected $platform;
 
     /** @var BlobType */
@@ -24,7 +23,7 @@ class BlobTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('blob');
+        $this->type     = new BlobType();
     }
 
     public function testBlobNullConvertsToPHPValue(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/BooleanTest.php b/tests/Doctrine/Tests/DBAL/Types/BooleanTest.php
index 0fe4a2d5a5e..7eefeb3f9f9 100644
--- a/tests/Doctrine/Tests/DBAL/Types/BooleanTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/BooleanTest.php
@@ -4,13 +4,12 @@
 
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\BooleanType;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 
 class BooleanTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var BooleanType */
@@ -19,7 +18,7 @@ class BooleanTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->getMockForAbstractClass(AbstractPlatform::class);
-        $this->type     = Type::getType('boolean');
+        $this->type     = new BooleanType();
     }
 
     public function testBooleanConvertsToDatabaseValue(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/DateImmutableTypeTest.php b/tests/Doctrine/Tests/DBAL/Types/DateImmutableTypeTest.php
index e06e9b02f11..46bbbd3fb39 100644
--- a/tests/Doctrine/Tests/DBAL/Types/DateImmutableTypeTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/DateImmutableTypeTest.php
@@ -8,7 +8,6 @@
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\ConversionException;
 use Doctrine\DBAL\Types\DateImmutableType;
-use Doctrine\DBAL\Types\Type;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
@@ -16,7 +15,7 @@
 
 class DateImmutableTypeTest extends TestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var DateImmutableType */
@@ -24,8 +23,8 @@ class DateImmutableTypeTest extends TestCase
 
     protected function setUp(): void
     {
-        $this->type     = Type::getType('date_immutable');
         $this->platform = $this->createMock(AbstractPlatform::class);
+        $this->type     = new DateImmutableType();
     }
 
     public function testFactoryCreatesCorrectType(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/DateIntervalTest.php b/tests/Doctrine/Tests/DBAL/Types/DateIntervalTest.php
index 6c85de36510..ee81bb0e5c7 100644
--- a/tests/Doctrine/Tests/DBAL/Types/DateIntervalTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/DateIntervalTest.php
@@ -7,14 +7,13 @@
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\ConversionException;
 use Doctrine\DBAL\Types\DateIntervalType;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 use stdClass;
 
 final class DateIntervalTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var DateIntervalType */
@@ -23,9 +22,7 @@ final class DateIntervalTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('dateinterval');
-
-        self::assertInstanceOf(DateIntervalType::class, $this->type);
+        $this->type     = new DateIntervalType();
     }
 
     public function testDateIntervalConvertsToDatabaseValue(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/DateTest.php b/tests/Doctrine/Tests/DBAL/Types/DateTest.php
index 1d97cceaa2c..17183125e1d 100644
--- a/tests/Doctrine/Tests/DBAL/Types/DateTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/DateTest.php
@@ -4,7 +4,7 @@
 
 use DateTime;
 use Doctrine\DBAL\Types\ConversionException;
-use Doctrine\DBAL\Types\Type;
+use Doctrine\DBAL\Types\DateType;
 
 use function date_default_timezone_set;
 
@@ -12,7 +12,7 @@ class DateTest extends BaseDateTypeTestCase
 {
     protected function setUp(): void
     {
-        $this->type = Type::getType('date');
+        $this->type = new DateType();
 
         parent::setUp();
     }
diff --git a/tests/Doctrine/Tests/DBAL/Types/DateTimeImmutableTypeTest.php b/tests/Doctrine/Tests/DBAL/Types/DateTimeImmutableTypeTest.php
index 4c3a772d344..72a3585fe12 100644
--- a/tests/Doctrine/Tests/DBAL/Types/DateTimeImmutableTypeTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/DateTimeImmutableTypeTest.php
@@ -8,7 +8,6 @@
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\ConversionException;
 use Doctrine\DBAL\Types\DateTimeImmutableType;
-use Doctrine\DBAL\Types\Type;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
@@ -16,7 +15,7 @@
 
 class DateTimeImmutableTypeTest extends TestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var DateTimeImmutableType */
@@ -24,8 +23,8 @@ class DateTimeImmutableTypeTest extends TestCase
 
     protected function setUp(): void
     {
-        $this->type     = Type::getType('datetime_immutable');
         $this->platform = $this->getMockBuilder(AbstractPlatform::class)->getMock();
+        $this->type     = new DateTimeImmutableType();
     }
 
     public function testFactoryCreatesCorrectType(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/DateTimeTest.php b/tests/Doctrine/Tests/DBAL/Types/DateTimeTest.php
index 72868f328a8..5bf92f811e2 100644
--- a/tests/Doctrine/Tests/DBAL/Types/DateTimeTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/DateTimeTest.php
@@ -4,13 +4,13 @@
 
 use DateTime;
 use Doctrine\DBAL\Types\ConversionException;
-use Doctrine\DBAL\Types\Type;
+use Doctrine\DBAL\Types\DateTimeType;
 
 class DateTimeTest extends BaseDateTypeTestCase
 {
     protected function setUp(): void
     {
-        $this->type = Type::getType('datetime');
+        $this->type = new DateTimeType();
 
         parent::setUp();
     }
@@ -29,7 +29,7 @@ public function testDateTimeConvertsToPHPValue(): void
     {
         // Birthday of jwage and also birthday of Doctrine. Send him a present ;)
         $date = $this->type->convertToPHPValue('1985-09-01 00:00:00', $this->platform);
-        self::assertInstanceOf('DateTime', $date);
+        self::assertInstanceOf(DateTime::class, $date);
         self::assertEquals('1985-09-01 00:00:00', $date->format('Y-m-d H:i:s'));
     }
 
diff --git a/tests/Doctrine/Tests/DBAL/Types/DateTimeTzImmutableTypeTest.php b/tests/Doctrine/Tests/DBAL/Types/DateTimeTzImmutableTypeTest.php
index eafaedcb729..7992d99b65f 100644
--- a/tests/Doctrine/Tests/DBAL/Types/DateTimeTzImmutableTypeTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/DateTimeTzImmutableTypeTest.php
@@ -8,7 +8,6 @@
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\ConversionException;
 use Doctrine\DBAL\Types\DateTimeTzImmutableType;
-use Doctrine\DBAL\Types\Type;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
@@ -16,7 +15,7 @@
 
 class DateTimeTzImmutableTypeTest extends TestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var DateTimeTzImmutableType */
@@ -24,8 +23,8 @@ class DateTimeTzImmutableTypeTest extends TestCase
 
     protected function setUp(): void
     {
-        $this->type     = Type::getType('datetimetz_immutable');
         $this->platform = $this->createMock(AbstractPlatform::class);
+        $this->type     = new DateTimeTzImmutableType();
     }
 
     public function testFactoryCreatesCorrectType(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/DateTimeTzTest.php b/tests/Doctrine/Tests/DBAL/Types/DateTimeTzTest.php
index f7367f283ec..f7696515f64 100644
--- a/tests/Doctrine/Tests/DBAL/Types/DateTimeTzTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/DateTimeTzTest.php
@@ -4,13 +4,13 @@
 
 use DateTime;
 use Doctrine\DBAL\Types\ConversionException;
-use Doctrine\DBAL\Types\Type;
+use Doctrine\DBAL\Types\DateTimeTzType;
 
 class DateTimeTzTest extends BaseDateTypeTestCase
 {
     protected function setUp(): void
     {
-        $this->type = Type::getType('datetimetz');
+        $this->type = new DateTimeTzType();
 
         parent::setUp();
     }
@@ -29,7 +29,7 @@ public function testDateTimeConvertsToPHPValue(): void
     {
         // Birthday of jwage and also birthday of Doctrine. Send him a present ;)
         $date = $this->type->convertToPHPValue('1985-09-01 00:00:00', $this->platform);
-        self::assertInstanceOf('DateTime', $date);
+        self::assertInstanceOf(DateTime::class, $date);
         self::assertEquals('1985-09-01 00:00:00', $date->format('Y-m-d H:i:s'));
     }
 
diff --git a/tests/Doctrine/Tests/DBAL/Types/DecimalTest.php b/tests/Doctrine/Tests/DBAL/Types/DecimalTest.php
index bf05598ab32..29f88f6f54a 100644
--- a/tests/Doctrine/Tests/DBAL/Types/DecimalTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/DecimalTest.php
@@ -4,13 +4,12 @@
 
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\DecimalType;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 
 class DecimalTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var DecimalType */
@@ -19,7 +18,7 @@ class DecimalTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('decimal');
+        $this->type     = new DecimalType();
     }
 
     public function testDecimalConvertsToPHPValue(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/FloatTest.php b/tests/Doctrine/Tests/DBAL/Types/FloatTest.php
index 44623c28b90..7316252cade 100644
--- a/tests/Doctrine/Tests/DBAL/Types/FloatTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/FloatTest.php
@@ -4,13 +4,12 @@
 
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\FloatType;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 
 class FloatTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var FloatType */
@@ -19,7 +18,7 @@ class FloatTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('float');
+        $this->type     = new FloatType();
     }
 
     public function testFloatConvertsToPHPValue(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/GuidTypeTest.php b/tests/Doctrine/Tests/DBAL/Types/GuidTypeTest.php
index 3615b687bd9..2c15c7cbd4b 100644
--- a/tests/Doctrine/Tests/DBAL/Types/GuidTypeTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/GuidTypeTest.php
@@ -4,13 +4,12 @@
 
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\GuidType;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 
 class GuidTypeTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var GuidType */
@@ -19,7 +18,7 @@ class GuidTypeTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('guid');
+        $this->type     = new GuidType();
     }
 
     public function testConvertToPHPValue(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/IntegerTest.php b/tests/Doctrine/Tests/DBAL/Types/IntegerTest.php
index 7241a9237e1..c8f9cf952f4 100644
--- a/tests/Doctrine/Tests/DBAL/Types/IntegerTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/IntegerTest.php
@@ -4,13 +4,12 @@
 
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\IntegerType;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 
 class IntegerTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var IntegerType */
@@ -19,7 +18,7 @@ class IntegerTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('integer');
+        $this->type     = new IntegerType();
     }
 
     public function testIntegerConvertsToPHPValue(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/JsonArrayTest.php b/tests/Doctrine/Tests/DBAL/Types/JsonArrayTest.php
index 4603f3d6206..2383543b322 100644
--- a/tests/Doctrine/Tests/DBAL/Types/JsonArrayTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/JsonArrayTest.php
@@ -5,7 +5,6 @@
 use Doctrine\DBAL\ParameterType;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\JsonArrayType;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\DBAL\Types\Types;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
@@ -16,7 +15,7 @@
 
 class JsonArrayTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     protected $platform;
 
     /** @var JsonArrayType */
@@ -25,7 +24,7 @@ class JsonArrayTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('json_array');
+        $this->type     = new JsonArrayType();
     }
 
     public function testReturnsBindingType(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/JsonTest.php b/tests/Doctrine/Tests/DBAL/Types/JsonTest.php
index 0cf41b7f867..158c7bb1a9c 100644
--- a/tests/Doctrine/Tests/DBAL/Types/JsonTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/JsonTest.php
@@ -6,7 +6,6 @@
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\ConversionException;
 use Doctrine\DBAL\Types\JsonType;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\DBAL\Types\Types;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
@@ -17,7 +16,7 @@
 
 class JsonTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     protected $platform;
 
     /** @var JsonType */
@@ -26,7 +25,7 @@ class JsonTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('json');
+        $this->type     = new JsonType();
     }
 
     public function testReturnsBindingType(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/ObjectTest.php b/tests/Doctrine/Tests/DBAL/Types/ObjectTest.php
index df961faa3b9..227fcef9554 100644
--- a/tests/Doctrine/Tests/DBAL/Types/ObjectTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/ObjectTest.php
@@ -5,7 +5,6 @@
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\ConversionException;
 use Doctrine\DBAL\Types\ObjectType;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 use stdClass;
@@ -14,7 +13,7 @@
 
 class ObjectTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var ObjectType */
@@ -23,7 +22,7 @@ class ObjectTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('object');
+        $this->type     = new ObjectType();
     }
 
     public function testObjectConvertsToDatabaseValue(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/SmallIntTest.php b/tests/Doctrine/Tests/DBAL/Types/SmallIntTest.php
index 31ed1a310dd..4c5981f4729 100644
--- a/tests/Doctrine/Tests/DBAL/Types/SmallIntTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/SmallIntTest.php
@@ -4,13 +4,12 @@
 
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\SmallIntType;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 
 class SmallIntTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var SmallIntType */
@@ -19,7 +18,7 @@ class SmallIntTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('smallint');
+        $this->type     = new SmallIntType();
     }
 
     public function testSmallIntConvertsToPHPValue(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/StringTest.php b/tests/Doctrine/Tests/DBAL/Types/StringTest.php
index 688a06ba870..5041e942e75 100644
--- a/tests/Doctrine/Tests/DBAL/Types/StringTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/StringTest.php
@@ -4,13 +4,12 @@
 
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\StringType;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 
 class StringTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var StringType */
@@ -19,7 +18,7 @@ class StringTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        $this->type     = Type::getType('string');
+        $this->type     = new StringType();
     }
 
     public function testReturnsSqlDeclarationFromPlatformVarchar(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/TimeImmutableTypeTest.php b/tests/Doctrine/Tests/DBAL/Types/TimeImmutableTypeTest.php
index c9518fe6dbf..b2365f54a40 100644
--- a/tests/Doctrine/Tests/DBAL/Types/TimeImmutableTypeTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/TimeImmutableTypeTest.php
@@ -8,7 +8,6 @@
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\ConversionException;
 use Doctrine\DBAL\Types\TimeImmutableType;
-use Doctrine\DBAL\Types\Type;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
@@ -16,7 +15,7 @@
 
 class TimeImmutableTypeTest extends TestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var TimeImmutableType */
@@ -24,8 +23,8 @@ class TimeImmutableTypeTest extends TestCase
 
     protected function setUp(): void
     {
-        $this->type     = Type::getType('time_immutable');
         $this->platform = $this->getMockBuilder(AbstractPlatform::class)->getMock();
+        $this->type     = new TimeImmutableType();
     }
 
     public function testFactoryCreatesCorrectType(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/TimeTest.php b/tests/Doctrine/Tests/DBAL/Types/TimeTest.php
index 8bec5c2ae37..ceb1e9ee7d0 100644
--- a/tests/Doctrine/Tests/DBAL/Types/TimeTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/TimeTest.php
@@ -2,21 +2,22 @@
 
 namespace Doctrine\Tests\DBAL\Types;
 
+use DateTime;
 use Doctrine\DBAL\Types\ConversionException;
-use Doctrine\DBAL\Types\Type;
+use Doctrine\DBAL\Types\TimeType;
 
 class TimeTest extends BaseDateTypeTestCase
 {
     protected function setUp(): void
     {
-        $this->type = Type::getType('time');
+        $this->type = new TimeType();
 
         parent::setUp();
     }
 
     public function testTimeConvertsToPHPValue(): void
     {
-        self::assertInstanceOf('DateTime', $this->type->convertToPHPValue('5:30:55', $this->platform));
+        self::assertInstanceOf(DateTime::class, $this->type->convertToPHPValue('5:30:55', $this->platform));
     }
 
     public function testDateFieldResetInPHPValue(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/VarDateTimeImmutableTypeTest.php b/tests/Doctrine/Tests/DBAL/Types/VarDateTimeImmutableTypeTest.php
index a8652a6115b..442409ac425 100644
--- a/tests/Doctrine/Tests/DBAL/Types/VarDateTimeImmutableTypeTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/VarDateTimeImmutableTypeTest.php
@@ -7,14 +7,13 @@
 use Doctrine\DBAL\ParameterType;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\ConversionException;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\DBAL\Types\VarDateTimeImmutableType;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
 class VarDateTimeImmutableTypeTest extends TestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var VarDateTimeImmutableType */
@@ -22,12 +21,8 @@ class VarDateTimeImmutableTypeTest extends TestCase
 
     protected function setUp(): void
     {
-        if (! Type::hasType('vardatetime_immutable')) {
-            Type::addType('vardatetime_immutable', VarDateTimeImmutableType::class);
-        }
-
-        $this->type     = Type::getType('vardatetime_immutable');
         $this->platform = $this->getMockForAbstractClass(AbstractPlatform::class);
+        $this->type     = new VarDateTimeImmutableType();
     }
 
     public function testReturnsName(): void
diff --git a/tests/Doctrine/Tests/DBAL/Types/VarDateTimeTest.php b/tests/Doctrine/Tests/DBAL/Types/VarDateTimeTest.php
index 586b36e89cd..206c2e094d5 100644
--- a/tests/Doctrine/Tests/DBAL/Types/VarDateTimeTest.php
+++ b/tests/Doctrine/Tests/DBAL/Types/VarDateTimeTest.php
@@ -5,14 +5,13 @@
 use DateTime;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\ConversionException;
-use Doctrine\DBAL\Types\Type;
 use Doctrine\DBAL\Types\VarDateTimeType;
 use Doctrine\Tests\DbalTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
 
 class VarDateTimeTest extends DbalTestCase
 {
-    /** @var AbstractPlatform|MockObject */
+    /** @var AbstractPlatform&MockObject */
     private $platform;
 
     /** @var VarDateTimeType */
@@ -21,11 +20,7 @@ class VarDateTimeTest extends DbalTestCase
     protected function setUp(): void
     {
         $this->platform = $this->createMock(AbstractPlatform::class);
-        if (! Type::hasType('vardatetime')) {
-            Type::addType('vardatetime', VarDateTimeType::class);
-        }
-
-        $this->type = Type::getType('vardatetime');
+        $this->type     = new VarDateTimeType();
     }
 
     public function testDateTimeConvertsToDatabaseValue(): void
@@ -42,7 +37,7 @@ public function testDateTimeConvertsToPHPValue(): void
     {
         // Birthday of jwage and also birthday of Doctrine. Send him a present ;)
         $date = $this->type->convertToPHPValue('1985-09-01 00:00:00', $this->platform);
-        self::assertInstanceOf('DateTime', $date);
+        self::assertInstanceOf(DateTime::class, $date);
         self::assertEquals('1985-09-01 00:00:00', $date->format('Y-m-d H:i:s'));
         self::assertEquals('000000', $date->format('u'));
     }
@@ -56,7 +51,7 @@ public function testInvalidDateTimeFormatConversion(): void
     public function testConversionWithMicroseconds(): void
     {
         $date = $this->type->convertToPHPValue('1985-09-01 00:00:00.123456', $this->platform);
-        self::assertInstanceOf('DateTime', $date);
+        self::assertInstanceOf(DateTime::class, $date);
         self::assertEquals('1985-09-01 00:00:00', $date->format('Y-m-d H:i:s'));
         self::assertEquals('123456', $date->format('u'));
     }
diff --git a/tests/Doctrine/Tests/TestUtil.php b/tests/Doctrine/Tests/TestUtil.php
index f45ee6e232f..3a21df3910e 100644
--- a/tests/Doctrine/Tests/TestUtil.php
+++ b/tests/Doctrine/Tests/TestUtil.php
@@ -2,6 +2,7 @@
 
 namespace Doctrine\Tests;
 
+use Doctrine\Common\EventSubscriber;
 use Doctrine\DBAL\Connection;
 use Doctrine\DBAL\DriverManager;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
@@ -137,6 +138,8 @@ private static function addDbEventSubscribers(Connection $conn): void
         }
 
         $evm = $conn->getEventManager();
+
+        /** @psalm-var class-string<EventSubscriber> $subscriberClass */
         foreach (explode(',', $GLOBALS['db_event_subscribers']) as $subscriberClass) {
             $subscriberInstance = new $subscriberClass();
             $evm->addEventSubscriber($subscriberInstance);