diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index d94b3ef..742c01b 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -47,7 +47,7 @@ jobs:
     strategy:
       matrix:
         php-version:
-          - "7.2"
+          - "7.4"
 
     services:
       mysql:
@@ -81,7 +81,7 @@ jobs:
         run: "composer update --no-interaction --no-progress --no-suggest --prefer-lowest"
 
       - name: "Run PHPUnit"
-        run: "vendor/bin/phpunit -c phpunit.mysql8.xml --coverage-clover=coverage.xml"
+        run: "vendor/bin/phpunit --no-coverage"
 
   phpunit-code-coverage:
     name: "PHPUnit with Code Coverage"
@@ -90,7 +90,7 @@ jobs:
     strategy:
       matrix:
         php-version:
-          - "7.2"
+          - "7.4"
 
     services:
       mysql:
@@ -137,9 +137,7 @@ jobs:
     strategy:
       matrix:
         php-version:
-          - "7.1"
-          - "7.3"
-          - "7.4"
+          - "8.0"
 
     services:
       mysql:
@@ -161,7 +159,6 @@ jobs:
         with:
           php-version: "${{ matrix.php-version }}"
           extensions: ""
-          coverage: "pcov"
 
       - name: "Cache dependencies installed with composer"
         uses: "actions/cache@v1"
@@ -174,4 +171,4 @@ jobs:
         run: "composer install --no-interaction --no-progress --no-suggest"
 
       - name: "Run PHPUnit"
-        run: "vendor/bin/phpunit"
+        run: "vendor/bin/phpunit --no-coverage"
diff --git a/composer.json b/composer.json
index 8853c89..dbd4a3c 100644
--- a/composer.json
+++ b/composer.json
@@ -13,21 +13,21 @@
         }
     ],
     "require": {
-    	"php": ">=7.1.0",
+    	"php": ">=7.4.0 || ^8.0",
     	"mouf/utils.common.conditioninterface": "~2.0",
     	"mouf/utils.value.value-interface": "~1.0",
     	"mouf/utils.common.paginable-interface": "~1.0",
     	"mouf/utils.common.sortable-interface": "~1.0",
         "mouf/schema-analyzer": "~1.0",
         "twig/twig": "^2.11 || ^3",
-        "greenlion/php-sql-parser": "^4.1.2",
+        "greenlion/php-sql-parser": "^4.3",
         "doctrine/cache": "^1.5"
     },
     "require-dev": {
-        "phpunit/phpunit": "^7.5.10",
+        "phpunit/phpunit": "^9.5",
         "satooshi/php-coveralls": "~1.0",
         "doctrine/dbal": "~2.5",
-        "phpstan/phpstan": "^0.11.7"
+        "phpstan/phpstan": "^0.12.82"
     },
     "suggest": {
       "doctrine/dbal": "To support more databases than just MySQL and to use MagicJoin feature",
@@ -67,6 +67,6 @@
     "minimum-stability": "dev",
     "prefer-stable": true,
     "scripts": {
-        "phpstan": "vendor/bin/phpstan analyse -c phpstan.neon src"
+        "phpstan": "vendor/bin/phpstan analyse -c phpstan.neon"
     }
 }
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
new file mode 100644
index 0000000..d8d1d0b
--- /dev/null
+++ b/phpstan-baseline.neon
@@ -0,0 +1,197 @@
+parameters:
+	ignoreErrors:
+		-
+			message: "#^Method Mouf\\\\Database\\\\QueryWriter\\\\QueryResult\\:\\:val\\(\\) should return array but returns Mouf\\\\Database\\\\QueryWriter\\\\ResultSet\\.$#"
+			count: 1
+			path: src/Mouf/Database/QueryWriter/QueryResult.php
+
+		-
+			message: "#^Method Mouf\\\\Database\\\\QueryWriter\\\\Utils\\\\DbHelper\\:\\:getAll\\(\\) has no return typehint specified\\.$#"
+			count: 1
+			path: src/Mouf/Database/QueryWriter/Utils/DbHelper.php
+
+		-
+			message: "#^Parameter \\#1 \\$rightOperand of method SQLParser\\\\Node\\\\AbstractInListOperator\\:\\:refactorParameterToExpression\\(\\) expects SQLParser\\\\Node\\\\NodeInterface, array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface\\|string given\\.$#"
+			count: 1
+			path: src/SQLParser/Node/AbstractInListOperator.php
+
+		-
+			message: "#^Cannot access offset 0 on array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface\\.$#"
+			count: 1
+			path: src/SQLParser/Node/AbstractInListOperator.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\AbstractTwoOperandsOperator\\:\\:setLeftOperand\\(\\) has no return typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/AbstractTwoOperandsOperator.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\AbstractTwoOperandsOperator\\:\\:setRightOperand\\(\\) has no return typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/AbstractTwoOperandsOperator.php
+
+		-
+			message: "#^Cannot call method walk\\(\\) on array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface\\|string\\.$#"
+			count: 2
+			path: src/SQLParser/Node/AbstractTwoOperandsOperator.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\Between\\:\\:setLeftOperand\\(\\) has no return typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/Between.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\Between\\:\\:setMinValueOperand\\(\\) has no return typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/Between.php
+
+		-
+			message: "#^Cannot call method walk\\(\\) on array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface\\|string\\.$#"
+			count: 1
+			path: src/SQLParser/Node/Between.php
+
+		-
+			message: "#^Cannot call method walk\\(\\) on array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface\\|string\\.$#"
+			count: 1
+			path: src/SQLParser/Node/CaseOperation.php
+
+		-
+			message: "#^Cannot access offset mixed on array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface\\.$#"
+			count: 2
+			path: src/SQLParser/Node/Expression.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\NodeFactory\\:\\:toObject\\(\\) has no return typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/NodeFactory.php
+
+		-
+			message: "#^Parameter \\#1 \\$refClause of method SQLParser\\\\Node\\\\SubQuery\\:\\:setRefClause\\(\\) expects array\\<SQLParser\\\\Node\\\\NodeInterface\\>, array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface given\\.$#"
+			count: 1
+			path: src/SQLParser/Node/NodeFactory.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\NodeFactory\\:\\:buildFromSubtree\\(\\) has no return typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/NodeFactory.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\NodeFactory\\:\\:buildFromSubtree\\(\\) has parameter \\$subTree with no typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/NodeFactory.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\NodeFactory\\:\\:mapArrayToNodeObjectList\\(\\) has no return typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/NodeFactory.php
+
+		-
+			message: "#^Property SQLParser\\\\Node\\\\NodeFactory\\:\\:\\$PRECEDENCE has no typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/NodeFactory.php
+
+		-
+			message: "#^Property SQLParser\\\\Node\\\\NodeFactory\\:\\:\\$OPERATOR_TO_CLASS has no typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/NodeFactory.php
+
+		-
+			message: "#^Parameter \\#1 \\$var of function count expects array\\|Countable, array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface given\\.$#"
+			count: 1
+			path: src/SQLParser/Node/NodeFactory.php
+
+		-
+			message: "#^Parameter \\#2 \\.\\.\\.\\$args of function array_merge expects array, array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface given\\.$#"
+			count: 1
+			path: src/SQLParser/Node/NodeFactory.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\NodeFactory\\:\\:array_map_deep\\(\\) has no return typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/NodeFactory.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\NodeFactory\\:\\:array_map_deep\\(\\) has parameter \\$array with no typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/NodeFactory.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\NodeFactory\\:\\:array_map_deep\\(\\) has parameter \\$callback with no typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/NodeFactory.php
+
+		-
+			message: "#^Property SQLParser\\\\Node\\\\Operator\\:\\:\\$value has no typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/Operator.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\Operator\\:\\:getValue\\(\\) has no return typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/Operator.php
+
+		-
+			message: "#^Method SQLParser\\\\Node\\\\Operator\\:\\:setValue\\(\\) has no return typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Node/Operator.php
+
+		-
+			message: "#^Strict comparison using \\=\\=\\= between mixed and null will always evaluate to false\\.$#"
+			count: 1
+			path: src/SQLParser/Node/Parameter.php
+
+		-
+			message: "#^Argument of an invalid type array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface supplied for foreach, only iterables are supported\\.$#"
+			count: 1
+			path: src/SQLParser/Node/SimpleFunction.php
+
+		-
+			message: "#^Cannot access offset mixed on array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface\\.$#"
+			count: 2
+			path: src/SQLParser/Node/SimpleFunction.php
+
+		-
+			message: "#^Cannot access offset mixed on array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface\\.$#"
+			count: 2
+			path: src/SQLParser/Node/Table.php
+
+		-
+			message: "#^Elseif condition is always true\\.$#"
+			count: 1
+			path: src/SQLParser/Node/Table.php
+
+		-
+			message: "#^Property SQLParser\\\\Node\\\\Table\\:\\:\\$refClause \\(array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface\\) does not accept null\\.$#"
+			count: 1
+			path: src/SQLParser/Node/Table.php
+
+		-
+			message: "#^Method SQLParser\\\\Query\\\\Select\\:\\:overwriteInstanceDescriptor\\(\\) has parameter \\$name with no typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Query/Select.php
+
+		-
+			message: "#^Method SQLParser\\\\Query\\\\Select\\:\\:walkChildren\\(\\) has parameter \\$children with no typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Query/Select.php
+
+		-
+			message: "#^Argument of an invalid type array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface supplied for foreach, only iterables are supported\\.$#"
+			count: 1
+			path: src/SQLParser/Query/StatementFactory.php
+
+		-
+			message: "#^Cannot access offset mixed on \\(array\\<SQLParser\\\\Node\\\\NodeInterface\\>&nonEmpty\\)\\|SQLParser\\\\Node\\\\NodeInterface\\.$#"
+			count: 1
+			path: src/SQLParser/Query/StatementFactory.php
+
+		-
+			message: "#^Parameter \\#1 \\$columns of method SQLParser\\\\Query\\\\Select\\:\\:setColumns\\(\\) expects array\\<SQLParser\\\\Node\\\\NodeInterface\\>, array\\<SQLParser\\\\Node\\\\NodeInterface\\>\\|SQLParser\\\\Node\\\\NodeInterface given\\.$#"
+			count: 1
+			path: src/SQLParser/Query/StatementFactory.php
+
+		-
+			message: "#^Method SQLParser\\\\Query\\\\Union\\:\\:overwriteInstanceDescriptor\\(\\) has parameter \\$name with no typehint specified\\.$#"
+			count: 1
+			path: src/SQLParser/Query/Union.php
+
diff --git a/phpstan.neon b/phpstan.neon
index 588a228..c85f7c3 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -1,7 +1,14 @@
+includes:
+    - phpstan-baseline.neon
+
 parameters:
     level: 7
+    paths:
+        - src
     inferPrivatePropertyTypeFromConstructor: true
+    checkMissingIterableValueType: false
+    checkGenericClassInNonGenericObjectType: false
     ignoreErrors:
         - "#Mouf\\\\MoufManager#"
         - "#Mouf\\\\MoufInstanceDescriptor#"
-        - '#Method Mouf\\Database\\QueryWriter\\Utils\\FindParametersService::findParameters\(\) should return array<string> but returns array<int, int\|string>#'
\ No newline at end of file
+        - '#Method Mouf\\Database\\QueryWriter\\Utils\\FindParametersService::findParameters\(\) should return array<string> but returns array<int, int\|string>#'
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 95a50ce..61da686 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -12,7 +12,8 @@
 >
 
     <php>
-        <var name="db_host" value="localhost" />
+        <var name="db_host" value="127.0.0.1" />
+        <var name="db_port" value="3306"/>
         <var name="db_username" value="root" />
         <var name="db_password" value="" />
         <var name="db_driver" value="pdo_mysql"/>
diff --git a/src/Mouf/Database/MagicQuery.php b/src/Mouf/Database/MagicQuery.php
index c9158ef..7dbdb8e 100644
--- a/src/Mouf/Database/MagicQuery.php
+++ b/src/Mouf/Database/MagicQuery.php
@@ -2,6 +2,7 @@
 
 namespace Mouf\Database;
 
+use Doctrine\Common\Cache\Cache;
 use Doctrine\DBAL\Connection;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Platforms\MySqlPlatform;
@@ -34,21 +35,20 @@
 class MagicQuery
 {
     private $connection;
+    /** @var Cache */
     private $cache;
+    /** @var SchemaAnalyzer */
     private $schemaAnalyzer;
-    /**
-     * @var AbstractPlatform
-     */
+    /** @var AbstractPlatform */
     private $platform;
-    /**
-     * @var Environment
-     */
+    /** @var Environment */
     private $twigEnvironment;
+    /** @var bool */
     private $enableTwig = false;
 
     /**
      * @param \Doctrine\DBAL\Connection    $connection
-     * @param \Doctrine\Common\Cache\Cache $cache
+     * @param Cache $cache
      * @param SchemaAnalyzer               $schemaAnalyzer (optional). If not set, it is initialized from the connection.
      */
     public function __construct($connection = null, $cache = null, SchemaAnalyzer $schemaAnalyzer = null)
@@ -205,11 +205,9 @@ public function toSql(NodeInterface $sqlNode, array $parameters = array(), bool
     /**
      * Scans the SQL statement and replaces the "magicjoin" part with the correct joins.
      *
-     * @param NodeInterface $select
-     *
      * @throws MagicQueryMissingConnectionException
      */
-    private function magicJoin(NodeInterface $select)
+    private function magicJoin(NodeInterface $select): void
     {
         // Let's find if this is a MagicJoin query.
         $magicJoinDetector = new DetectMagicJoinSelectVisitor();
@@ -227,12 +225,8 @@ private function magicJoin(NodeInterface $select)
 
     /**
      * For one given MagicJoin select, let's apply MagicJoin.
-     *
-     * @param MagicJoinSelect $magicJoinSelect
-     *
-     * @return Select
      */
-    private function magicJoinOnOneQuery(MagicJoinSelect $magicJoinSelect)
+    private function magicJoinOnOneQuery(MagicJoinSelect $magicJoinSelect): void
     {
         $tableSearchNodeTraverser = new NodeTraverser();
         $detectTableVisitor = new DetectTablesVisitor($magicJoinSelect->getMainTable());
@@ -316,7 +310,7 @@ private function getSchemaAnalyzer()
         return $this->schemaAnalyzer;
     }
 
-    private function getConnectionUniqueId(Connection $connection)
+    private function getConnectionUniqueId(Connection $connection): string
     {
         return hash('md4', $connection->getHost().'-'.$connection->getPort().'-'.$connection->getDatabase().'-'.$connection->getDriver()->getName());
     }
diff --git a/src/Mouf/Database/MagicQuery/Twig/SqlTwigEnvironmentFactory.php b/src/Mouf/Database/MagicQuery/Twig/SqlTwigEnvironmentFactory.php
index 55cf0c5..589e7e1 100644
--- a/src/Mouf/Database/MagicQuery/Twig/SqlTwigEnvironmentFactory.php
+++ b/src/Mouf/Database/MagicQuery/Twig/SqlTwigEnvironmentFactory.php
@@ -12,9 +12,10 @@
  */
 class SqlTwigEnvironmentFactory
 {
+    /** @var Environment|null */
     private static $twig;
 
-    public static function getTwigEnvironment()
+    public static function getTwigEnvironment(): Environment
     {
         if (self::$twig) {
             return self::$twig;
@@ -45,7 +46,7 @@ public static function getTwigEnvironment()
         return $twig;
     }
 
-    private static function getCacheDirectory()
+    private static function getCacheDirectory(): string
     {
         // If we are running on a Unix environment, let's prepend the cache with the user id of the PHP process.
         // This way, we can avoid rights conflicts.
diff --git a/src/Mouf/Database/MagicQuery/Twig/StringLoader.php b/src/Mouf/Database/MagicQuery/Twig/StringLoader.php
index 2f80793..7e22074 100644
--- a/src/Mouf/Database/MagicQuery/Twig/StringLoader.php
+++ b/src/Mouf/Database/MagicQuery/Twig/StringLoader.php
@@ -19,13 +19,8 @@ class StringLoader implements LoaderInterface
 {
     /**
      * {@inheritdoc}
-     */
-    public function getSource($name)
-    {
-        return $name;
-    }
-    /**
-     * {@inheritdoc}
+     *
+     * @param string $name
      */
     public function getCacheKey($name): string
     {
@@ -33,6 +28,9 @@ public function getCacheKey($name): string
     }
     /**
      * {@inheritdoc}
+     *
+     * @param string $name
+     * @param int $time
      */
     public function isFresh($name, $time): bool
     {
diff --git a/src/Mouf/Database/QueryWriter/QueryResult.php b/src/Mouf/Database/QueryWriter/QueryResult.php
index 4b44f6b..d0287b3 100644
--- a/src/Mouf/Database/QueryWriter/QueryResult.php
+++ b/src/Mouf/Database/QueryWriter/QueryResult.php
@@ -44,8 +44,10 @@ class QueryResult implements ArrayValueInterface, PaginableInterface, SortableIn
      */
     private $parameters = array();
 
-    private $limit;
+    /** @var int|null */
     private $offset;
+    /** @var int|null */
+    private $limit;
 
     /**
      * @param Select     $select
@@ -62,7 +64,7 @@ public function __construct(Select $select, Connection $connection)
      *
      * @param array<string, string>|array<string, ValueInterface>|ArrayValueInterface $parameters
      */
-    public function setParameters($parameters)
+    public function setParameters($parameters): void
     {
         $this->parameters = $parameters;
     }
@@ -98,7 +100,7 @@ public function toSql()
      * @param int $limit
      * @param int $offset
      */
-    public function paginate($limit, $offset = 0)
+    public function paginate($limit, $offset = 0): void
     {
         $this->limit = $limit;
         $this->offset = $offset;
@@ -107,7 +109,7 @@ public function paginate($limit, $offset = 0)
     /* (non-PHPdoc)
      * @see \Mouf\Utils\Common\SortableInterface::sort()
      */
-    public function sort($key, $direction = SortableInterface::ASC)
+    public function sort($key, $direction = SortableInterface::ASC): void
     {
         $result = $this->findColumnByKey($key);
         if ($result != null) {
diff --git a/src/Mouf/Database/QueryWriter/ResultSet.php b/src/Mouf/Database/QueryWriter/ResultSet.php
index fbb8212..5cffdec 100644
--- a/src/Mouf/Database/QueryWriter/ResultSet.php
+++ b/src/Mouf/Database/QueryWriter/ResultSet.php
@@ -2,7 +2,8 @@
 
 namespace Mouf\Database\QueryWriter;
 
-use Doctrine\DBAL\Statement;
+use Doctrine\DBAL\FetchMode;
+use Doctrine\DBAL\Driver\Statement;
 
 /**
  * Wraps the results of a PDOStatement.
@@ -11,20 +12,20 @@
  */
 class ResultSet implements \Iterator
 {
-    /**
-     * @var \PDOStatement|Statement
-     */
+    /** @var Statement */
     private $statement;
-    private $castToClass;
+    /** @var int */
     private $key = 0;
+    /** @var array|false */
     private $result;
+    /** @var bool */
     private $fetched = false;
+    /** @var int */
     private $rewindCalls = 0;
 
-    public function __construct($statement, $castToClass = '')
+    public function __construct(Statement $statement)
     {
         $this->statement = $statement;
-        $this->castToClass = $castToClass;
     }
 
     public function rewind()
@@ -35,6 +36,9 @@ public function rewind()
         }
     }
 
+    /**
+     * @return array|false
+     */
     public function current()
     {
         if (!$this->fetched) {
@@ -44,6 +48,9 @@ public function current()
         return $this->result;
     }
 
+    /**
+     * @return int
+     */
     public function key()
     {
         return $this->key;
@@ -56,9 +63,9 @@ public function next()
         $this->fetch();
     }
 
-    private function fetch()
+    private function fetch(): void
     {
-        $this->result = $this->statement->fetch(\PDO::FETCH_ASSOC);
+        $this->result = $this->statement->fetch(FetchMode::ASSOCIATIVE);
         $this->fetched = true;
     }
 
diff --git a/src/Mouf/Database/QueryWriter/Utils/DbHelper.php b/src/Mouf/Database/QueryWriter/Utils/DbHelper.php
index 5cb2c75..bab502a 100644
--- a/src/Mouf/Database/QueryWriter/Utils/DbHelper.php
+++ b/src/Mouf/Database/QueryWriter/Utils/DbHelper.php
@@ -2,14 +2,15 @@
 
 namespace Mouf\Database\QueryWriter\Utils;
 
+use Doctrine\DBAL\Connection;
 use Mouf\MoufManager;
 
 class DbHelper
 {
-    public static function getAll($sql, $offset, $limit)
+    public static function getAll(string $sql, ?int $offset, ?int $limit)
     {
+        /** @var Connection $dbalConnection */
         $dbalConnection = MoufManager::getMoufManager()->get('dbalConnection');
-        /* @var $dbalConnection \Doctrine\DBAL\Connection */
         $sql .= self::getFromLimitString($offset, $limit);
         $statement = $dbalConnection->executeQuery($sql);
         $results = $statement->fetchAll();
@@ -23,15 +24,13 @@ public static function getAll($sql, $offset, $limit)
         return $array;
     }
 
-    public static function getFromLimitString($from = null, $limit = null)
+    public static function getFromLimitString(?int $from = null, ?int $limit = null): string
     {
         if ($limit !== null) {
-            $limitInt = (int) $limit;
-            $queryStr = ' LIMIT '.$limitInt;
+            $queryStr = ' LIMIT '.$limit;
 
             if ($from !== null) {
-                $fromInt = (int) $from;
-                $queryStr .= ' OFFSET '.$fromInt;
+                $queryStr .= ' OFFSET '.$from;
             }
 
             return $queryStr;
diff --git a/src/Mouf/Database/QueryWriter/Utils/FindParametersService.php b/src/Mouf/Database/QueryWriter/Utils/FindParametersService.php
index 2ddb0ee..628251c 100644
--- a/src/Mouf/Database/QueryWriter/Utils/FindParametersService.php
+++ b/src/Mouf/Database/QueryWriter/Utils/FindParametersService.php
@@ -25,7 +25,7 @@ public static function findParameters(MoufInstanceDescriptor $instanceDescriptor
      * @param MoufInstanceDescriptor $instanceDescriptor
      * @param array<string>          $visitedInstances   The list of names of visited instances.
      */
-    private static function recursiveFindParameters(MoufInstanceDescriptor $instanceDescriptor, array $visitedInstances = array(), array $foundParameters = array())
+    private static function recursiveFindParameters(MoufInstanceDescriptor $instanceDescriptor, array $visitedInstances = array(), array $foundParameters = array()): array
     {
         if (isset($visitedInstances[$instanceDescriptor->getIdentifierName()])) {
             return array($visitedInstances, $foundParameters);
diff --git a/src/SQLParser/Node/AbstractInListOperator.php b/src/SQLParser/Node/AbstractInListOperator.php
index 69a2949..6519bab 100644
--- a/src/SQLParser/Node/AbstractInListOperator.php
+++ b/src/SQLParser/Node/AbstractInListOperator.php
@@ -12,7 +12,7 @@
  */
 abstract class AbstractInListOperator extends AbstractTwoOperandsOperator
 {
-    protected function getSql(array $parameters, AbstractPlatform $platform, $indent = 0, $conditionsMode = self::CONDITION_APPLY, bool $extrapolateParameters = true)
+    protected function getSql(array $parameters, AbstractPlatform $platform, int $indent = 0, int $conditionsMode = self::CONDITION_APPLY, bool $extrapolateParameters = true): string
     {
         $rightOperand = $this->getRightOperand();
 
diff --git a/src/SQLParser/Node/AbstractManyInstancesOperator.php b/src/SQLParser/Node/AbstractManyInstancesOperator.php
index bcc1bdc..2827426 100644
--- a/src/SQLParser/Node/AbstractManyInstancesOperator.php
+++ b/src/SQLParser/Node/AbstractManyInstancesOperator.php
@@ -15,9 +15,10 @@
  */
 abstract class AbstractManyInstancesOperator implements NodeInterface
 {
+    /** @var array */
     private $operands;
 
-    public function getOperands()
+    public function getOperands(): array
     {
         return $this->operands;
     }
@@ -30,7 +31,7 @@ public function getOperands()
      *
      * @param array<NodeInterface> $operands
      */
-    public function setOperands($operands)
+    public function setOperands($operands): void
     {
         if (!is_array($operands)) {
             $operands = array($operands);
@@ -108,5 +109,5 @@ public function walk(VisitorInterface $visitor)
      *
      * @return string
      */
-    abstract protected function getOperatorSymbol();
+    abstract protected function getOperatorSymbol(): string;
 }
diff --git a/src/SQLParser/Node/AbstractTwoOperandsOperator.php b/src/SQLParser/Node/AbstractTwoOperandsOperator.php
index 390c08c..890f3ad 100644
--- a/src/SQLParser/Node/AbstractTwoOperandsOperator.php
+++ b/src/SQLParser/Node/AbstractTwoOperandsOperator.php
@@ -18,8 +18,12 @@ abstract class AbstractTwoOperandsOperator implements NodeInterface
 {
     use ConditionTrait;
 
+    /** @var NodeInterface|NodeInterface[]|string */
     private $leftOperand;
 
+    /**
+     * @return NodeInterface|NodeInterface[]|string
+     */
     public function getLeftOperand()
     {
         return $this->leftOperand;
@@ -37,8 +41,12 @@ public function setLeftOperand($leftOperand)
         $this->leftOperand = $leftOperand;
     }
 
+    /** @var NodeInterface|NodeInterface[]|string */
     private $rightOperand;
 
+    /**
+     * @return NodeInterface|NodeInterface[]|string
+     */
     public function getRightOperand()
     {
         return $this->rightOperand;
@@ -122,7 +130,7 @@ public function toSql(array $parameters, AbstractPlatform $platform, int $indent
         return $sql;
     }
 
-    protected function getSql(array $parameters, AbstractPlatform $platform, $indent = 0, $conditionsMode = self::CONDITION_APPLY, bool $extrapolateParameters = true)
+    protected function getSql(array $parameters, AbstractPlatform $platform, int $indent = 0, int $conditionsMode = self::CONDITION_APPLY, bool $extrapolateParameters = true): string
     {
         $sql = NodeFactory::toSql($this->leftOperand, $platform, $parameters, ' ', false, $indent, $conditionsMode, $extrapolateParameters);
         $sql .= ' '.$this->getOperatorSymbol().' ';
@@ -165,5 +173,5 @@ public function walk(VisitorInterface $visitor)
     /**
      * Returns the symbol for this operator.
      */
-    abstract protected function getOperatorSymbol();
+    abstract protected function getOperatorSymbol(): string;
 }
diff --git a/src/SQLParser/Node/AggregateFunction.php b/src/SQLParser/Node/AggregateFunction.php
index 248b484..2c675a6 100644
--- a/src/SQLParser/Node/AggregateFunction.php
+++ b/src/SQLParser/Node/AggregateFunction.php
@@ -45,6 +45,7 @@
  */
 class AggregateFunction implements NodeInterface
 {
+    /** @var string */
     private $functionName;
 
     /**
@@ -64,13 +65,17 @@ public function getFunctionName()
      *
      * @param string $functionName
      */
-    public function setFunctionName($functionName)
+    public function setFunctionName($functionName): void
     {
         $this->functionName = $functionName;
     }
 
+    /** @var NodeInterface[] */
     private $subTree;
 
+    /**
+     * @return NodeInterface[]
+     */
     public function getSubTree()
     {
         return $this->subTree;
@@ -83,13 +88,17 @@ public function getSubTree()
      *
      * @param array<NodeInterface> $subTree
      */
-    public function setSubTree($subTree)
+    public function setSubTree($subTree): void
     {
         $this->subTree = $subTree;
     }
 
+    /** @var string */
     private $alias;
 
+    /**
+     * @return string
+     */
     public function getAlias()
     {
         return $this->alias;
@@ -98,15 +107,19 @@ public function getAlias()
     /**
      * Sets the alias.
      *
-     * @param string $alias
+     * @param string|array $alias
      */
-    public function setAlias($alias)
+    public function setAlias($alias): void
     {
-        $this->alias = $alias;
+        $this->alias = is_array($alias) ? $alias['name'] : $alias;
     }
 
+    /** @var string */
     private $direction;
 
+    /**
+     * @return string
+     */
     public function getDirection()
     {
         return $this->direction;
@@ -119,7 +132,7 @@ public function getDirection()
      *
      * @param string $direction
      */
-    public function setDirection($direction)
+    public function setDirection($direction): void
     {
         $this->direction = $direction;
     }
@@ -160,10 +173,7 @@ public function toSql(array $parameters, AbstractPlatform $platform, int $indent
             $sql .= $subTreeSql;
             $sql .= ')';
             if ($this->alias) {
-                // defensive fix:
-                $alias = is_array($this->alias) ? $this->alias['name'] : $this->alias;
-
-                $sql .= ' AS '.$alias;
+                $sql .= ' AS '.$this->alias;
             }
             if ($this->direction) {
                 $sql .= ' '.$this->direction;
diff --git a/src/SQLParser/Node/AndOp.php b/src/SQLParser/Node/AndOp.php
index 67d4cdc..3d375ad 100644
--- a/src/SQLParser/Node/AndOp.php
+++ b/src/SQLParser/Node/AndOp.php
@@ -44,7 +44,7 @@ class AndOp extends AbstractManyInstancesOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'AND';
     }
diff --git a/src/SQLParser/Node/Between.php b/src/SQLParser/Node/Between.php
index d19e0a2..88c6886 100644
--- a/src/SQLParser/Node/Between.php
+++ b/src/SQLParser/Node/Between.php
@@ -17,8 +17,12 @@
  */
 class Between implements NodeInterface
 {
+    /** @var NodeInterface|NodeInterface[]|string */
     private $leftOperand;
 
+    /**
+     * @return NodeInterface|NodeInterface[]|string
+     */
     public function getLeftOperand()
     {
         return $this->leftOperand;
@@ -73,7 +77,7 @@ public function getMaxValueOperand()
     /**
      * @param NodeInterface $maxValueOperand
      */
-    public function setMaxValueOperand(NodeInterface $maxValueOperand)
+    public function setMaxValueOperand(NodeInterface $maxValueOperand): void
     {
         $this->maxValueOperand = $maxValueOperand;
     }
@@ -88,9 +92,9 @@ public function setMaxValueOperand(NodeInterface $maxValueOperand)
      *
      * @Important IfSet
      *
-     * @param ConditionInterface $minValueCondition
+     * @param ConditionInterface|null $minValueCondition
      */
-    public function setMinValueCondition(ConditionInterface $minValueCondition = null)
+    public function setMinValueCondition(ConditionInterface $minValueCondition = null): void
     {
         $this->minValueCondition = $minValueCondition;
     }
@@ -105,9 +109,9 @@ public function setMinValueCondition(ConditionInterface $minValueCondition = nul
      *
      * @Important IfSet
      *
-     * @param ConditionInterface $maxValueCondition
+     * @param ConditionInterface|null $maxValueCondition
      */
-    public function setMaxValueCondition(ConditionInterface $maxValueCondition = null)
+    public function setMaxValueCondition(ConditionInterface $maxValueCondition = null): void
     {
         $this->maxValueCondition = $maxValueCondition;
     }
diff --git a/src/SQLParser/Node/BitwiseAnd.php b/src/SQLParser/Node/BitwiseAnd.php
index 49d437b..1d052ec 100644
--- a/src/SQLParser/Node/BitwiseAnd.php
+++ b/src/SQLParser/Node/BitwiseAnd.php
@@ -14,7 +14,7 @@ class BitwiseAnd extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '&';
     }
diff --git a/src/SQLParser/Node/BitwiseOr.php b/src/SQLParser/Node/BitwiseOr.php
index 8133fdd..8d3f3f1 100644
--- a/src/SQLParser/Node/BitwiseOr.php
+++ b/src/SQLParser/Node/BitwiseOr.php
@@ -14,7 +14,7 @@ class BitwiseOr extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '|';
     }
diff --git a/src/SQLParser/Node/BitwiseXor.php b/src/SQLParser/Node/BitwiseXor.php
index 8ebc1c4..ba7f3b9 100644
--- a/src/SQLParser/Node/BitwiseXor.php
+++ b/src/SQLParser/Node/BitwiseXor.php
@@ -14,7 +14,7 @@ class BitwiseXor extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '^';
     }
diff --git a/src/SQLParser/Node/CaseOperation.php b/src/SQLParser/Node/CaseOperation.php
index 8d4923d..5165d0f 100644
--- a/src/SQLParser/Node/CaseOperation.php
+++ b/src/SQLParser/Node/CaseOperation.php
@@ -15,8 +15,12 @@
  */
 class CaseOperation implements NodeInterface
 {
+    /** @var NodeInterface|NodeInterface[]|string */
     private $operation;
 
+    /**
+     * @return NodeInterface|NodeInterface[]|string
+     */
     public function getOperation()
     {
         return $this->operation;
@@ -29,7 +33,7 @@ public function getOperation()
      *
      * @param NodeInterface|NodeInterface[]|string $operation
      */
-    public function setOperation($operation)
+    public function setOperation($operation): void
     {
         $this->operation = $operation;
     }
diff --git a/src/SQLParser/Node/ColRef.php b/src/SQLParser/Node/ColRef.php
index cf76ce9..2fea15a 100644
--- a/src/SQLParser/Node/ColRef.php
+++ b/src/SQLParser/Node/ColRef.php
@@ -44,6 +44,7 @@
  */
 class ColRef implements NodeInterface
 {
+    /** @var mixed */
     private $database;
 
     /**
@@ -61,11 +62,12 @@ public function getDatabase()
      *
      * @param mixed $database
      */
-    public function setDatabase($database)
+    public function setDatabase($database): void
     {
         $this->database = $database;
     }
 
+    /** @var string */
     private $table;
 
     /**
@@ -85,11 +87,12 @@ public function getTable()
      *
      * @param string $table
      */
-    public function setTable($table)
+    public function setTable($table): void
     {
         $this->table = $table;
     }
 
+    /** @var string */
     private $column;
 
     /**
@@ -109,11 +112,12 @@ public function getColumn()
      *
      * @param string $column
      */
-    public function setColumn($column)
+    public function setColumn($column): void
     {
         $this->column = $column;
     }
 
+    /** @var string */
     private $alias;
 
     /**
@@ -133,11 +137,12 @@ public function getAlias()
      *
      * @param string $alias
      */
-    public function setAlias($alias)
+    public function setAlias($alias): void
     {
         $this->alias = $alias;
     }
 
+    /** @var string */
     private $direction;
 
     /**
@@ -157,7 +162,7 @@ public function getDirection()
      *
      * @param string $direction
      */
-    public function setDirection($direction)
+    public function setDirection($direction): void
     {
         $this->direction = $direction;
     }
diff --git a/src/SQLParser/Node/ConstNode.php b/src/SQLParser/Node/ConstNode.php
index 9f97b0c..0b2231f 100644
--- a/src/SQLParser/Node/ConstNode.php
+++ b/src/SQLParser/Node/ConstNode.php
@@ -44,9 +44,14 @@
  */
 class ConstNode implements NodeInterface
 {
+    /** @var string */
     private $value;
+    /** @var bool */
     private $isString = true;
 
+    /**
+     * @return string
+     */
     public function getValue()
     {
         return $this->value;
@@ -59,13 +64,13 @@ public function getValue()
      *
      * @param string $value
      */
-    public function setValue($value)
+    public function setValue($value): void
     {
         $this->value = $value;
     }
 
     /**
-     * @return mixed
+     * @return bool
      */
     public function getIsString()
     {
@@ -73,9 +78,9 @@ public function getIsString()
     }
 
     /**
-     * @param mixed $isString
+     * @param bool $isString
      */
-    public function setIsString($isString)
+    public function setIsString($isString): void
     {
         $this->isString = $isString;
     }
diff --git a/src/SQLParser/Node/Different.php b/src/SQLParser/Node/Different.php
index 23ce118..56a4600 100644
--- a/src/SQLParser/Node/Different.php
+++ b/src/SQLParser/Node/Different.php
@@ -16,12 +16,12 @@ class Different extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '<>';
     }
 
-    protected function getSql(array $parameters, AbstractPlatform $platform, $indent = 0, $conditionsMode = self::CONDITION_APPLY, bool $extrapolateParameters = true)
+    protected function getSql(array $parameters, AbstractPlatform $platform, int $indent = 0, int $conditionsMode = self::CONDITION_APPLY, bool $extrapolateParameters = true): string
     {
         $rightOperand = $this->getRightOperand();
         if ($rightOperand instanceof Parameter && !isset($parameters[$rightOperand->getName()])) {
diff --git a/src/SQLParser/Node/Div.php b/src/SQLParser/Node/Div.php
index 5b369c6..a76ea1d 100644
--- a/src/SQLParser/Node/Div.php
+++ b/src/SQLParser/Node/Div.php
@@ -14,7 +14,7 @@ class Div extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'DIV';
     }
diff --git a/src/SQLParser/Node/Divide.php b/src/SQLParser/Node/Divide.php
index d6dd340..6760295 100644
--- a/src/SQLParser/Node/Divide.php
+++ b/src/SQLParser/Node/Divide.php
@@ -14,7 +14,7 @@ class Divide extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '/';
     }
diff --git a/src/SQLParser/Node/ElseOperation.php b/src/SQLParser/Node/ElseOperation.php
index 40407d0..5441d32 100644
--- a/src/SQLParser/Node/ElseOperation.php
+++ b/src/SQLParser/Node/ElseOperation.php
@@ -14,7 +14,7 @@ class ElseOperation extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'ELSE';
     }
diff --git a/src/SQLParser/Node/Equal.php b/src/SQLParser/Node/Equal.php
index 5af09b0..6e53db9 100644
--- a/src/SQLParser/Node/Equal.php
+++ b/src/SQLParser/Node/Equal.php
@@ -14,12 +14,12 @@ class Equal extends AbstractTwoOperandsOperator
     /**
      * Returns the symbol for this operator.
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '=';
     }
 
-    protected function getSql(array $parameters, AbstractPlatform $platform, $indent = 0, $conditionsMode = self::CONDITION_APPLY, bool $extrapolateParameters = true)
+    protected function getSql(array $parameters, AbstractPlatform $platform, int $indent = 0, int $conditionsMode = self::CONDITION_APPLY, bool $extrapolateParameters = true): string
     {
         $rightOperand = $this->getRightOperand();
         if ($rightOperand instanceof Parameter && !isset($parameters[$rightOperand->getName()])) {
diff --git a/src/SQLParser/Node/Expression.php b/src/SQLParser/Node/Expression.php
index 5a4761d..887c4bc 100644
--- a/src/SQLParser/Node/Expression.php
+++ b/src/SQLParser/Node/Expression.php
@@ -46,6 +46,7 @@
  */
 class Expression implements NodeInterface, BypassableInterface
 {
+    /** @var string */
     private $baseExpression;
 
     /**
@@ -63,13 +64,17 @@ public function getBaseExpression()
      *
      * @param string $baseExpression
      */
-    public function setBaseExpression($baseExpression)
+    public function setBaseExpression($baseExpression): void
     {
         $this->baseExpression = $baseExpression;
     }
 
+    /** @var NodeInterface[]|NodeInterface */
     private $subTree;
 
+    /**
+     * @return NodeInterface|NodeInterface[]
+     */
     public function getSubTree()
     {
         return $this->subTree;
@@ -82,14 +87,17 @@ public function getSubTree()
      *
      * @param array<NodeInterface>|NodeInterface $subTree
      */
-    public function setSubTree($subTree)
+    public function setSubTree($subTree): void
     {
-        $this->subTree = $subTree;
-        $this->subTree = NodeFactory::simplify($this->subTree);
+        $this->subTree = NodeFactory::simplify($subTree);
     }
 
+    /** @var string */
     private $alias;
 
+    /**
+     * @return string
+     */
     public function getAlias()
     {
         return $this->alias;
@@ -102,13 +110,17 @@ public function getAlias()
      *
      * @param string $alias
      */
-    public function setAlias($alias)
+    public function setAlias($alias): void
     {
         $this->alias = $alias;
     }
 
+    /** @var string */
     private $direction;
 
+    /**
+     * @return string
+     */
     public function getDiretion()
     {
         return $this->direction;
@@ -121,11 +133,12 @@ public function getDiretion()
      *
      * @param string $direction
      */
-    public function setDirection($direction)
+    public function setDirection($direction): void
     {
         $this->direction = $direction;
     }
 
+    /** @var bool */
     private $brackets = false;
 
     /**
@@ -145,11 +158,12 @@ public function hasBrackets()
      *
      * @param bool $brackets
      */
-    public function setBrackets($brackets)
+    public function setBrackets($brackets): void
     {
         $this->brackets = $brackets;
     }
 
+    /** @var string */
     private $delimiter = ' ';
 
     /**
@@ -165,7 +179,7 @@ public function getDelimiter()
      *
      * @param string $delimiter
      */
-    public function setDelimiter($delimiter)
+    public function setDelimiter($delimiter): void
     {
         $this->delimiter = $delimiter;
     }
diff --git a/src/SQLParser/Node/Greater.php b/src/SQLParser/Node/Greater.php
index 1347bf4..6ad8b20 100644
--- a/src/SQLParser/Node/Greater.php
+++ b/src/SQLParser/Node/Greater.php
@@ -14,7 +14,7 @@ class Greater extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '>';
     }
diff --git a/src/SQLParser/Node/GreaterOrEqual.php b/src/SQLParser/Node/GreaterOrEqual.php
index e9bcbdd..9f9484b 100644
--- a/src/SQLParser/Node/GreaterOrEqual.php
+++ b/src/SQLParser/Node/GreaterOrEqual.php
@@ -14,7 +14,7 @@ class GreaterOrEqual extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '>=';
     }
diff --git a/src/SQLParser/Node/In.php b/src/SQLParser/Node/In.php
index f8c3448..4c90592 100644
--- a/src/SQLParser/Node/In.php
+++ b/src/SQLParser/Node/In.php
@@ -16,7 +16,7 @@ class In extends AbstractInListOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'IN';
     }
diff --git a/src/SQLParser/Node/Is.php b/src/SQLParser/Node/Is.php
index 0a4557c..6d3d43d 100644
--- a/src/SQLParser/Node/Is.php
+++ b/src/SQLParser/Node/Is.php
@@ -14,7 +14,7 @@ class Is extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'IS';
     }
diff --git a/src/SQLParser/Node/IsNot.php b/src/SQLParser/Node/IsNot.php
index 4e02e90..2f245e7 100644
--- a/src/SQLParser/Node/IsNot.php
+++ b/src/SQLParser/Node/IsNot.php
@@ -14,7 +14,7 @@ class IsNot extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'IS NOT';
     }
diff --git a/src/SQLParser/Node/Less.php b/src/SQLParser/Node/Less.php
index 492bbcc..54ee1a1 100644
--- a/src/SQLParser/Node/Less.php
+++ b/src/SQLParser/Node/Less.php
@@ -14,7 +14,7 @@ class Less extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '<';
     }
diff --git a/src/SQLParser/Node/LessOrEqual.php b/src/SQLParser/Node/LessOrEqual.php
index 26379fd..e555a5b 100644
--- a/src/SQLParser/Node/LessOrEqual.php
+++ b/src/SQLParser/Node/LessOrEqual.php
@@ -14,7 +14,7 @@ class LessOrEqual extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '<=';
     }
diff --git a/src/SQLParser/Node/Like.php b/src/SQLParser/Node/Like.php
index b892aaa..f000cd7 100644
--- a/src/SQLParser/Node/Like.php
+++ b/src/SQLParser/Node/Like.php
@@ -14,7 +14,7 @@ class Like extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'LIKE';
     }
diff --git a/src/SQLParser/Node/LimitNode.php b/src/SQLParser/Node/LimitNode.php
index 1a70261..c262dc6 100644
--- a/src/SQLParser/Node/LimitNode.php
+++ b/src/SQLParser/Node/LimitNode.php
@@ -44,8 +44,12 @@
  */
 class LimitNode implements NodeInterface
 {
+    /** @var string */
     private $value;
 
+    /**
+     * @return string
+     */
     public function getValue()
     {
         return $this->value;
@@ -58,7 +62,7 @@ public function getValue()
      *
      * @param string $value
      */
-    public function setValue($value)
+    public function setValue($value): void
     {
         $this->value = $value;
     }
diff --git a/src/SQLParser/Node/Minus.php b/src/SQLParser/Node/Minus.php
index f178fa3..623bb85 100644
--- a/src/SQLParser/Node/Minus.php
+++ b/src/SQLParser/Node/Minus.php
@@ -14,7 +14,7 @@ class Minus extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '-';
     }
diff --git a/src/SQLParser/Node/Modulo.php b/src/SQLParser/Node/Modulo.php
index 91f74a3..3683038 100644
--- a/src/SQLParser/Node/Modulo.php
+++ b/src/SQLParser/Node/Modulo.php
@@ -14,7 +14,7 @@ class Modulo extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '%';
     }
diff --git a/src/SQLParser/Node/Multiply.php b/src/SQLParser/Node/Multiply.php
index 6698f47..4ca2a75 100644
--- a/src/SQLParser/Node/Multiply.php
+++ b/src/SQLParser/Node/Multiply.php
@@ -14,7 +14,7 @@ class Multiply extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '*';
     }
diff --git a/src/SQLParser/Node/NodeFactory.php b/src/SQLParser/Node/NodeFactory.php
index 8384326..63d8965 100644
--- a/src/SQLParser/Node/NodeFactory.php
+++ b/src/SQLParser/Node/NodeFactory.php
@@ -556,6 +556,8 @@ public static function mapArrayToNodeObjectList(array $items)
      * Takes an array of nodes (including operators) and try to build a tree from it.
      *
      * @param NodeInterface[]|NodeInterface $nodes
+     *
+     * @return NodeInterface[]|NodeInterface
      */
     public static function simplify($nodes)
     {
@@ -571,7 +573,8 @@ public static function simplify($nodes)
 
         // Let's transform "NOT" + "IN" into "NOT IN"
         $newNodes = array();
-        for ($i = 0; $i < count($nodes); ++$i) {
+        $nodesCount = count($nodes);
+        for ($i = 0; $i < $nodesCount; ++$i) {
             $node = $nodes[$i];
             if ($node instanceof Operator && isset($nodes[$i + 1]) && $nodes[$i + 1] instanceof Operator
                     && strtoupper($node->getValue()) == 'IS' && strtoupper($nodes[$i + 1]->getValue()) == 'NOT') {
@@ -599,7 +602,8 @@ public static function simplify($nodes)
 
         // Handle AGAINST function. Without this patch params will be placed after AGAINST() and not inside the brackets
         $newNodes = array();
-        for ($i = 0; $i < count($nodes); ++$i) {
+        $nodesCount = count($nodes);
+        for ($i = 0; $i < $nodesCount; ++$i) {
             $node = $nodes[$i];
             if ($node instanceof SimpleFunction && $node->getBaseExpression() === 'AGAINST' && isset($nodes[$i + 1])) {
                 $node->setSubTree($nodes[$i + 1]);
@@ -648,7 +652,7 @@ public static function simplify($nodes)
                 if ($operand instanceof Expression) {
                     if (empty($operand->getBaseExpression())) {
                         $subTree = $operand->getSubTree();
-                        if (count($subTree) == 1) {
+                        if (count($subTree) === 1) {
                             $newNodes = array_merge($newNodes, self::simplify($subTree));
                         } else {
                             $newNodes[] = $operand;
diff --git a/src/SQLParser/Node/NotIn.php b/src/SQLParser/Node/NotIn.php
index 103af1b..36b98b6 100644
--- a/src/SQLParser/Node/NotIn.php
+++ b/src/SQLParser/Node/NotIn.php
@@ -14,7 +14,7 @@ class NotIn extends AbstractInListOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'NOT IN';
     }
diff --git a/src/SQLParser/Node/NotLike.php b/src/SQLParser/Node/NotLike.php
index 5258399..7c5749f 100644
--- a/src/SQLParser/Node/NotLike.php
+++ b/src/SQLParser/Node/NotLike.php
@@ -14,7 +14,7 @@ class NotLike extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'NOT LIKE';
     }
diff --git a/src/SQLParser/Node/NullCompatibleEqual.php b/src/SQLParser/Node/NullCompatibleEqual.php
index f49f803..61ac1bb 100644
--- a/src/SQLParser/Node/NullCompatibleEqual.php
+++ b/src/SQLParser/Node/NullCompatibleEqual.php
@@ -14,7 +14,7 @@ class NullCompatibleEqual extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '<=>';
     }
diff --git a/src/SQLParser/Node/Operation.php b/src/SQLParser/Node/Operation.php
index a9aa43b..fe86789 100644
--- a/src/SQLParser/Node/Operation.php
+++ b/src/SQLParser/Node/Operation.php
@@ -39,9 +39,13 @@
  */
 class Operation extends AbstractManyInstancesOperator
 {
+    /** @var string */
     private $operator;
 
-    public function getOperatorSymbol()
+    /**
+     * @return string
+     */
+    public function getOperatorSymbol(): string
     {
         return $this->operator;
     }
@@ -51,7 +55,7 @@ public function getOperatorSymbol()
      *
      * @param string $operator
      */
-    public function setOperatorSymbol($operator)
+    public function setOperatorSymbol($operator): void
     {
         $this->operator = $operator;
     }
diff --git a/src/SQLParser/Node/OrOp.php b/src/SQLParser/Node/OrOp.php
index 6885eac..9595e12 100644
--- a/src/SQLParser/Node/OrOp.php
+++ b/src/SQLParser/Node/OrOp.php
@@ -44,7 +44,7 @@ class OrOp extends AbstractManyInstancesOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'OR';
     }
diff --git a/src/SQLParser/Node/Parameter.php b/src/SQLParser/Node/Parameter.php
index 40186d3..4ced389 100644
--- a/src/SQLParser/Node/Parameter.php
+++ b/src/SQLParser/Node/Parameter.php
@@ -44,7 +44,9 @@
  */
 class Parameter implements NodeInterface, BypassableInterface
 {
+    /** @var string */
     protected $name;
+    /** @var bool */
     protected $discardedOnNull = true;
 
     /**
@@ -65,7 +67,7 @@ public function getName()
      *
      * @param string $name
      */
-    public function setName($name)
+    public function setName($name): void
     {
         if (strrpos($name, '!') === strlen($name) - 1) {
             $this->name = substr($name, 0, strlen($name) - 1);
@@ -102,7 +104,7 @@ public function getAutoPrepend()
      *
      * @param string $autoPrepend
      */
-    public function setAutoPrepend($autoPrepend)
+    public function setAutoPrepend($autoPrepend): self
     {
         $this->autoPrepend = $autoPrepend;
 
@@ -125,7 +127,7 @@ public function getAutoAppend()
      *
      * @param string $autoAppend
      */
-    public function setAutoAppend($autoAppend)
+    public function setAutoAppend($autoAppend): self
     {
         $this->autoAppend = $autoAppend;
 
diff --git a/src/SQLParser/Node/Plus.php b/src/SQLParser/Node/Plus.php
index 0a5b8a5..5636645 100644
--- a/src/SQLParser/Node/Plus.php
+++ b/src/SQLParser/Node/Plus.php
@@ -14,7 +14,7 @@ class Plus extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '+';
     }
diff --git a/src/SQLParser/Node/Regexp.php b/src/SQLParser/Node/Regexp.php
index 2cf84ad..f10a369 100644
--- a/src/SQLParser/Node/Regexp.php
+++ b/src/SQLParser/Node/Regexp.php
@@ -14,7 +14,7 @@ class Regexp extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'REGEXP';
     }
diff --git a/src/SQLParser/Node/Reserved.php b/src/SQLParser/Node/Reserved.php
index 8a39f23..dfb671a 100644
--- a/src/SQLParser/Node/Reserved.php
+++ b/src/SQLParser/Node/Reserved.php
@@ -44,6 +44,7 @@
  */
 class Reserved implements NodeInterface
 {
+    /** @var string */
     private $baseExpression;
 
     /**
@@ -61,11 +62,12 @@ public function getBaseExpression()
      *
      * @param string $baseExpression
      */
-    public function setBaseExpression($baseExpression)
+    public function setBaseExpression($baseExpression): void
     {
         $this->baseExpression = $baseExpression;
     }
 
+    /** @var bool */
     private $brackets = false;
 
     /**
@@ -85,7 +87,7 @@ public function hasBrackets()
      *
      * @param bool $brackets
      */
-    public function setBrackets($brackets)
+    public function setBrackets($brackets): void
     {
         $this->brackets = $brackets;
     }
diff --git a/src/SQLParser/Node/ShiftLeft.php b/src/SQLParser/Node/ShiftLeft.php
index 0d56b9c..3df1c14 100644
--- a/src/SQLParser/Node/ShiftLeft.php
+++ b/src/SQLParser/Node/ShiftLeft.php
@@ -14,7 +14,7 @@ class ShiftLeft extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '<<';
     }
diff --git a/src/SQLParser/Node/ShiftRight.php b/src/SQLParser/Node/ShiftRight.php
index e6f0eb9..71cc6d6 100644
--- a/src/SQLParser/Node/ShiftRight.php
+++ b/src/SQLParser/Node/ShiftRight.php
@@ -14,7 +14,7 @@ class ShiftRight extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return '>>';
     }
diff --git a/src/SQLParser/Node/SimpleFunction.php b/src/SQLParser/Node/SimpleFunction.php
index 58568f2..5b40c89 100644
--- a/src/SQLParser/Node/SimpleFunction.php
+++ b/src/SQLParser/Node/SimpleFunction.php
@@ -45,6 +45,7 @@
  */
 class SimpleFunction implements NodeInterface
 {
+    /** @var string */
     private $baseExpression;
 
     /**
@@ -62,13 +63,17 @@ public function getBaseExpression()
      *
      * @param string $baseExpression
      */
-    public function setBaseExpression($baseExpression)
+    public function setBaseExpression($baseExpression): void
     {
         $this->baseExpression = $baseExpression;
     }
 
+    /** @var NodeInterface[]|NodeInterface */
     private $subTree;
 
+    /**
+     * @return NodeInterface|NodeInterface[]
+     */
     public function getSubTree()
     {
         return $this->subTree;
@@ -81,14 +86,17 @@ public function getSubTree()
      *
      * @param array<NodeInterface>|NodeInterface $subTree
      */
-    public function setSubTree($subTree)
+    public function setSubTree($subTree): void
     {
-        $this->subTree = $subTree;
-        $this->subTree = NodeFactory::simplify($this->subTree);
+        $this->subTree = NodeFactory::simplify($subTree);
     }
 
+    /** @var string */
     private $alias;
 
+    /**
+     * @return string
+     */
     public function getAlias()
     {
         return $this->alias;
@@ -101,13 +109,17 @@ public function getAlias()
      *
      * @param string $alias
      */
-    public function setAlias($alias)
+    public function setAlias($alias): void
     {
         $this->alias = $alias;
     }
 
+    /** @var string */
     private $direction;
 
+    /**
+     * @return string
+     */
     public function getDiretion()
     {
         return $this->direction;
@@ -120,11 +132,12 @@ public function getDiretion()
      *
      * @param string $direction
      */
-    public function setDirection($direction)
+    public function setDirection($direction): void
     {
         $this->direction = $direction;
     }
 
+    /** @var bool */
     private $brackets = false;
 
     /**
diff --git a/src/SQLParser/Node/SubQuery.php b/src/SQLParser/Node/SubQuery.php
index 327637b..c5aa494 100644
--- a/src/SQLParser/Node/SubQuery.php
+++ b/src/SQLParser/Node/SubQuery.php
@@ -47,12 +47,13 @@
  */
 class SubQuery implements NodeInterface
 {
+    /** @var Select|Union|NodeInterface */
     private $subQuery;
 
     /**
      * Returns the list of subQuery statements.
      *
-     * @return Select|Union
+     * @return Select|Union|NodeInterface
      */
     public function getSubQuery()
     {
@@ -64,11 +65,12 @@ public function getSubQuery()
      *
      * @param Select|Union $subQuery
      */
-    public function setSubQuery($subQuery)
+    public function setSubQuery($subQuery): void
     {
         $this->subQuery = $subQuery;
     }
 
+    /** @var string */
     private $alias;
 
     /**
@@ -86,11 +88,12 @@ public function getAlias()
      *
      * @param string $alias
      */
-    public function setAlias($alias)
+    public function setAlias($alias): void
     {
         $this->alias = $alias;
     }
 
+    /** @var string */
     private $joinType;
 
     /**
@@ -108,11 +111,12 @@ public function getJoinType()
      *
      * @param string $joinType
      */
-    public function setJoinType($joinType)
+    public function setJoinType($joinType): void
     {
         $this->joinType = $joinType;
     }
 
+    /** @var NodeInterface[] */
     private $refClause;
 
     /**
@@ -130,7 +134,7 @@ public function getRefClause()
      *
      * @param NodeInterface[] $refClause
      */
-    public function setRefClause($refClause)
+    public function setRefClause($refClause): void
     {
         $this->refClause = $refClause;
     }
diff --git a/src/SQLParser/Node/Table.php b/src/SQLParser/Node/Table.php
index 38498cd..8d31021 100644
--- a/src/SQLParser/Node/Table.php
+++ b/src/SQLParser/Node/Table.php
@@ -45,6 +45,7 @@
  */
 class Table implements NodeInterface
 {
+    /** @var mixed */
     private $database;
 
     /**
@@ -62,11 +63,12 @@ public function getDatabase()
      *
      * @param mixed $database
      */
-    public function setDatabase($database)
+    public function setDatabase($database): void
     {
         $this->database = $database;
     }
 
+    /** @var string */
     private $table;
 
     /**
@@ -86,11 +88,12 @@ public function getTable()
      *
      * @param string $table
      */
-    public function setTable($table)
+    public function setTable($table): void
     {
         $this->table = $table;
     }
 
+    /** @var string */
     private $alias;
 
     /**
@@ -110,11 +113,12 @@ public function getAlias()
      *
      * @param string $alias
      */
-    public function setAlias($alias)
+    public function setAlias($alias): void
     {
         $this->alias = $alias;
     }
 
+    /** @var string */
     private $joinType;
 
     /**
@@ -134,11 +138,12 @@ public function getJoinType()
      *
      * @param string $joinType
      */
-    public function setJoinType($joinType)
+    public function setJoinType($joinType): void
     {
         $this->joinType = $joinType;
     }
 
+    /** @var NodeInterface[]|NodeInterface */
     private $refClause;
 
     /**
@@ -158,7 +163,7 @@ public function getRefClause()
      *
      * @param NodeInterface[]|NodeInterface $refClause
      */
-    public function setRefClause($refClause)
+    public function setRefClause($refClause): void
     {
         $this->refClause = $refClause;
     }
diff --git a/src/SQLParser/Node/Then.php b/src/SQLParser/Node/Then.php
index 8d4b066..7d23de3 100644
--- a/src/SQLParser/Node/Then.php
+++ b/src/SQLParser/Node/Then.php
@@ -14,7 +14,7 @@ class Then extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'THEN';
     }
diff --git a/src/SQLParser/Node/Traverser/CompositeVisitor.php b/src/SQLParser/Node/Traverser/CompositeVisitor.php
index d26ea95..123f06d 100644
--- a/src/SQLParser/Node/Traverser/CompositeVisitor.php
+++ b/src/SQLParser/Node/Traverser/CompositeVisitor.php
@@ -24,7 +24,7 @@ class CompositeVisitor implements VisitorInterface
      *
      * @param VisitorInterface $visitor
      */
-    public function addVisitor(VisitorInterface $visitor)
+    public function addVisitor(VisitorInterface $visitor): void
     {
         $this->visitors[] = $visitor;
         array_unshift($this->reverseVisitors, $visitor);
@@ -57,12 +57,7 @@ public function enterNode(NodeInterface $node)
     }
 
     /**
-     * Called on every node when the traverser leaves the node.
-     * The leaveNode() method can return a changed node, or null if nothing is changed.
-     * The leaveNode() method can also return the value NodeTraverser::REMOVE_NODE,
-     * which instructs the traverser to remove the current node.
-     *
-     * @param NodeInterface $node
+     * {@inheritDoc}
      */
     public function leaveNode(NodeInterface $node)
     {
diff --git a/src/SQLParser/Node/Traverser/DetectMagicJoinSelectVisitor.php b/src/SQLParser/Node/Traverser/DetectMagicJoinSelectVisitor.php
index 06459b6..c397270 100644
--- a/src/SQLParser/Node/Traverser/DetectMagicJoinSelectVisitor.php
+++ b/src/SQLParser/Node/Traverser/DetectMagicJoinSelectVisitor.php
@@ -11,15 +11,17 @@
  */
 class DetectMagicJoinSelectVisitor implements VisitorInterface
 {
+    /** @var Select|null */
     private $lastVisitedSelect;
 
+    /** @var array<MagicJoinSelect> */
     private $magicJoinSelects = array();
 
     /**
      * Removes all detected magic join selects.
      * Useful for reusing the visitor instance on another node traversal.
      */
-    public function resetVisitor()
+    public function resetVisitor(): void
     {
         $this->magicJoinSelects = array();
         $this->lastVisitedSelect = null;
@@ -61,14 +63,10 @@ public function enterNode(NodeInterface $node)
     }
 
     /**
-     * Called on every node when the traverser leaves the node.
-     * The leaveNode() method can return a changed node, or null if nothing is changed.
-     * The leaveNode() method can also return the value NodeTraverser::REMOVE_NODE,
-     * which instructs the traverser to remove the current node.
-     *
-     * @param NodeInterface $node
+     * {@inheritDoc}
      */
     public function leaveNode(NodeInterface $node)
     {
+        return null;
     }
 }
diff --git a/src/SQLParser/Node/Traverser/DetectTablesVisitor.php b/src/SQLParser/Node/Traverser/DetectTablesVisitor.php
index 0dbc5e9..a8fbd20 100644
--- a/src/SQLParser/Node/Traverser/DetectTablesVisitor.php
+++ b/src/SQLParser/Node/Traverser/DetectTablesVisitor.php
@@ -12,8 +12,10 @@
  */
 class DetectTablesVisitor implements VisitorInterface
 {
+    /** @var bool */
     private $isSelectVisited = false;
 
+    /** @var array<string, string> */
     private $tables = array();
 
     private $defaultTable;
@@ -22,7 +24,7 @@ class DetectTablesVisitor implements VisitorInterface
      * Removes all detected magic join selects.
      * Useful for reusing the visitor instance on another node traversal.
      */
-    public function resetVisitor()
+    public function resetVisitor(): void
     {
         $this->tables = array();
         $this->isSelectVisited = false;
@@ -75,15 +77,10 @@ public function enterNode(NodeInterface $node)
     }
 
     /**
-     * Called on every node when the traverser leaves the node.
-     * The leaveNode() method can return a changed node, or null if nothing is changed.
-     * The leaveNode() method can also return the value NodeTraverser::REMOVE_NODE,
-     * which instructs the traverser to remove the current node.
-     *
-     * @param NodeInterface $node
+     * {@inheritDoc}
      */
     public function leaveNode(NodeInterface $node)
     {
-        return;
+        return null;
     }
 }
diff --git a/src/SQLParser/Node/Traverser/NodeTraverser.php b/src/SQLParser/Node/Traverser/NodeTraverser.php
index 4654341..624547c 100644
--- a/src/SQLParser/Node/Traverser/NodeTraverser.php
+++ b/src/SQLParser/Node/Traverser/NodeTraverser.php
@@ -24,7 +24,7 @@ public function __construct()
      *
      * @param VisitorInterface $visitor
      */
-    public function addVisitor(VisitorInterface $visitor)
+    public function addVisitor(VisitorInterface $visitor): void
     {
         $this->visitor->addVisitor($visitor);
     }
@@ -34,7 +34,7 @@ public function addVisitor(VisitorInterface $visitor)
      *
      * @param NodeInterface $node
      */
-    public function walk(NodeInterface $node)
+    public function walk(NodeInterface $node): void
     {
         $node->walk($this->visitor);
     }
diff --git a/src/SQLParser/Node/Traverser/VisitorInterface.php b/src/SQLParser/Node/Traverser/VisitorInterface.php
index 81ae6c3..e654d48 100644
--- a/src/SQLParser/Node/Traverser/VisitorInterface.php
+++ b/src/SQLParser/Node/Traverser/VisitorInterface.php
@@ -29,6 +29,8 @@ public function enterNode(NodeInterface $node);
      * which instructs the traverser to remove the current node.
      *
      * @param NodeInterface $node
+     *
+     * @return NodeInterface|string|null
      */
     public function leaveNode(NodeInterface $node);
 }
diff --git a/src/SQLParser/Node/WhenConditions.php b/src/SQLParser/Node/WhenConditions.php
index 8b7c422..11bb62b 100644
--- a/src/SQLParser/Node/WhenConditions.php
+++ b/src/SQLParser/Node/WhenConditions.php
@@ -11,8 +11,12 @@
  */
 class WhenConditions extends AbstractManyInstancesOperator
 {
+    /** @var NodeInterface|NodeInterface[]|string */
     private $value;
 
+    /**
+     * @return NodeInterface|NodeInterface[]|string
+     */
     public function getValue()
     {
         return $this->value;
@@ -25,7 +29,7 @@ public function getValue()
      *
      * @param NodeInterface|NodeInterface[]|string $value
      */
-    public function setValue($value)
+    public function setValue($value): void
     {
         $this->value = $value;
     }
@@ -64,7 +68,7 @@ public function toSql(array $parameters, AbstractPlatform $platform, int $indent
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'WHEN';
     }
diff --git a/src/SQLParser/Node/XorOp.php b/src/SQLParser/Node/XorOp.php
index 26f98ed..4533152 100644
--- a/src/SQLParser/Node/XorOp.php
+++ b/src/SQLParser/Node/XorOp.php
@@ -14,7 +14,7 @@ class XorOp extends AbstractTwoOperandsOperator
      *
      * @return string
      */
-    protected function getOperatorSymbol()
+    protected function getOperatorSymbol(): string
     {
         return 'XOR';
     }
diff --git a/src/SQLParser/Query/Select.php b/src/SQLParser/Query/Select.php
index d737b15..e7b6079 100644
--- a/src/SQLParser/Query/Select.php
+++ b/src/SQLParser/Query/Select.php
@@ -54,6 +54,7 @@
  */
 class Select implements StatementInterface, NodeInterface
 {
+    /** @var bool */
     private $distinct;
 
     /**
@@ -71,11 +72,12 @@ public function getDistinct()
      *
      * @param bool $distinct
      */
-    public function setDistinct($distinct)
+    public function setDistinct($distinct): void
     {
         $this->distinct = $distinct;
     }
 
+    /** @var NodeInterface[] */
     private $columns;
 
     /**
@@ -93,11 +95,12 @@ public function getColumns()
      *
      * @param NodeInterface[] $columns
      */
-    public function setColumns($columns)
+    public function setColumns($columns): void
     {
         $this->columns = $columns;
     }
 
+    /** @var NodeInterface[] */
     private $from;
 
     /**
@@ -115,17 +118,18 @@ public function getFrom()
      *
      * @param NodeInterface[] $from
      */
-    public function setFrom($from)
+    public function setFrom($from): void
     {
         $this->from = $from;
     }
 
+    /** @var NodeInterface[]|NodeInterface */
     private $where;
 
     /**
      * Returns the list of where statements.
      *
-     * @return NodeInterface[]
+     * @return NodeInterface[]|NodeInterface
      */
     public function getWhere()
     {
@@ -137,17 +141,18 @@ public function getWhere()
      *
      * @param NodeInterface[]|NodeInterface $where
      */
-    public function setWhere($where)
+    public function setWhere($where): void
     {
         $this->where = $where;
     }
 
+    /** @var NodeInterface[]|NodeInterface */
     private $group;
 
     /**
      * Returns the list of group statements.
      *
-     * @return NodeInterface[]
+     * @return NodeInterface[]|NodeInterface
      */
     public function getGroup()
     {
@@ -159,11 +164,12 @@ public function getGroup()
      *
      * @param NodeInterface[]|NodeInterface $group
      */
-    public function setGroup($group)
+    public function setGroup($group): void
     {
         $this->group = $group;
     }
 
+    /** @var NodeInterface[]|NodeInterface */
     private $having;
 
     /**
@@ -181,11 +187,12 @@ public function getHaving()
      *
      * @param NodeInterface[]|NodeInterface $having
      */
-    public function setHaving($having)
+    public function setHaving($having): void
     {
         $this->having = $having;
     }
 
+    /** @var NodeInterface[]|NodeInterface */
     private $order;
 
     /**
@@ -203,11 +210,12 @@ public function getOrder()
      *
      * @param NodeInterface[]|NodeInterface $order
      */
-    public function setOrder($order)
+    public function setOrder($order): void
     {
         $this->order = $order;
     }
 
+    /** @var string[] */
     private $options;
 
     /**
@@ -225,11 +233,12 @@ public function getOptions()
      *
      * @param string[] $options
      */
-    public function setOptions($options)
+    public function setOptions($options): void
     {
         $this->options = $options;
     }
 
+    /** @var NodeInterface */
     private $limit;
 
     /**
@@ -243,11 +252,12 @@ public function getLimit()
     /**
      * @param NodeInterface $limit
      */
-    public function setLimit($limit)
+    public function setLimit($limit): void
     {
         $this->limit = $limit;
     }
 
+    /** @var NodeInterface */
     private $offset;
 
     /**
@@ -261,7 +271,7 @@ public function getOffset()
     /**
      * @param NodeInterface $offset
      */
-    public function setOffset($offset)
+    public function setOffset($offset): void
     {
         $this->offset = $offset;
     }
@@ -435,7 +445,7 @@ public function walk(VisitorInterface $visitor)
         return $visitor->leaveNode($node);
     }
 
-    private function walkChildren(&$children, VisitorInterface $visitor)
+    private function walkChildren(&$children, VisitorInterface $visitor): void
     {
         if ($children) {
             if (is_array($children)) {
diff --git a/src/SQLParser/Query/StatementFactory.php b/src/SQLParser/Query/StatementFactory.php
index a3cb5ee..e5cebaf 100644
--- a/src/SQLParser/Query/StatementFactory.php
+++ b/src/SQLParser/Query/StatementFactory.php
@@ -2,6 +2,7 @@
 
 namespace SQLParser\Query;
 
+use Mouf\Database\MagicQueryException;
 use SQLParser\Node\NodeFactory;
 use SQLParser\Node\Operator;
 use SQLParser\Node\Reserved;
@@ -13,6 +14,10 @@
  */
 class StatementFactory
 {
+    /**
+     * @return Select|Union
+     * @throws MagicQueryException
+     */
     public static function toObject(array $desc)
     {
         if (isset($desc['SELECT'])) {
@@ -88,6 +93,7 @@ public static function toObject(array $desc)
 
             return $select;
         } elseif (isset($desc['UNION'])) {
+            /** @var Select[] $selects */
             $selects = array_map([self::class, 'toObject'], $desc['UNION']);
 
             return new Union($selects);
diff --git a/src/SQLParser/Query/Union.php b/src/SQLParser/Query/Union.php
index 762e2a1..255ecf3 100644
--- a/src/SQLParser/Query/Union.php
+++ b/src/SQLParser/Query/Union.php
@@ -105,10 +105,10 @@ public function walk(VisitorInterface $visitor)
     }
 
     /**
-     * @param (Select|null)[] $children
+     * @param array<Select|null> $children
      * @param VisitorInterface $visitor
      */
-    private function walkChildren(array &$children, VisitorInterface $visitor)
+    private function walkChildren(array &$children, VisitorInterface $visitor): void
     {
         if ($children) {
             foreach ($children as $key => $operand) {
diff --git a/tests/Mouf/Database/MagicQuery/Twig/SqlTwigEnvironmentFactoryTest.php b/tests/Mouf/Database/MagicQuery/Twig/SqlTwigEnvironmentFactoryTest.php
index 742daec..7d2fdc5 100644
--- a/tests/Mouf/Database/MagicQuery/Twig/SqlTwigEnvironmentFactoryTest.php
+++ b/tests/Mouf/Database/MagicQuery/Twig/SqlTwigEnvironmentFactoryTest.php
@@ -4,12 +4,10 @@
 
 use Mouf\Database\MagicQuery\Twig\SqlTwigEnvironmentFactory;
 use PHPUnit\Framework\TestCase;
+use Twig\Error\RuntimeError;
 
 class SqlTwigEnvironmentFactoryTest extends TestCase
 {
-    /**
-     *
-     */
     public function testIf()
     {
         $twig = SqlTwigEnvironmentFactory::getTwigEnvironment();
@@ -17,12 +15,10 @@ public function testIf()
         $this->assertEquals('SELECT * FROM toto WHERE id = :id', $sql);
     }
 
-    /**
-     * @expectedException \Twig\Error\RuntimeError
-     */
     public function testException()
     {
         $twig = SqlTwigEnvironmentFactory::getTwigEnvironment();
+        $this->expectException(RuntimeError::class);
         $twig->render('SELECT * FROM toto WHERE id = {{ id }}', ['id' => 'hello']);
     }
 }
diff --git a/tests/Mouf/Database/MagicQueryTest.php b/tests/Mouf/Database/MagicQueryTest.php
index 4fd9b3e..47e2d43 100644
--- a/tests/Mouf/Database/MagicQueryTest.php
+++ b/tests/Mouf/Database/MagicQueryTest.php
@@ -210,33 +210,29 @@ public function testStandardSelect()
         $this->assertEquals($sql, self::simplifySql($magicQuery->build($sql)));
     }
 
-    /**
-     * @expectedException \Mouf\Database\MagicQueryException
-     */
     public function testInNullException() {
         $magicQuery = new MagicQuery();
 
         $sql = 'SELECT * FROM users WHERE status IN :statuses!';
+        $this->expectException(MagicQueryException::class);
         $magicQuery->build($sql, ['statuses' => NULL]);
     }
 
-    /**
-     * @expectedException \Mouf\Database\MagicQueryException
-     */
     public function testInvalidSql() {
         $magicQuery = new MagicQuery();
 
         $sql = 'SELECT * FROM users WHERE date_end => :startDate';
+        $this->expectException(MagicQueryException::class);
         $this->assertEquals('SELECT * FROM users WHERE date_end => \'2014-06-06\'', self::simplifySql($magicQuery->build($sql, ['startDate' => '2014-06-06'])));
     }
 
     public function testWithCache()
     {
-        global $db_url;
         $connectionParams = array(
             'user' => $GLOBALS['db_username'],
             'password' => $GLOBALS['db_password'],
             'host' => $GLOBALS['db_host'],
+            'port' => $GLOBALS['db_port'],
             'driver' => $GLOBALS['db_driver'],
         );
         $conn = \Doctrine\DBAL\DriverManager::getConnection($connectionParams);
@@ -252,14 +248,12 @@ public function testWithCache()
         $this->assertEquals($sql, self::simplifySql($magicQuery->build($sql)));
     }
 
-    /**
-     * @expectedException \Mouf\Database\MagicQueryParserException
-     */
     public function testParseError()
     {
         $magicQuery = new MagicQuery();
 
         $sql = '';
+        $this->expectException(MagicQueryParserException::class);
         $magicQuery->build($sql);
     }
 
@@ -392,20 +386,15 @@ public function testMatchAgainst()
         $this->assertEquals($expectedSql, self::simplifySql($magicQuery->build($sql, $params)));
     }
 
-    /**
-     * @expectedException \Mouf\Database\MagicQueryMissingConnectionException
-     */
     public function testMisconfiguration()
     {
         $magicQuery = new MagicQuery();
 
         $sql = "SELECT role.* FROM magicjoin(role) WHERE right.label = 'my_right'";
+        $this->expectException(MagicQueryMissingConnectionException::class);
         $magicQuery->build($sql);
     }
 
-    /**
-     *
-     */
     public function testTwig()
     {
         $magicQuery = new MagicQuery();