diff --git a/src/Client.php b/src/Client.php
index 43f27441..cb7eaa54 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -47,7 +47,7 @@ public function __construct(ConnectionManager $connectionManager, EventDispatche
     /**
      * Run a Cypher statement against the default database or the database specified.
      *
-     * @param $query
+     * @param string      $query
      * @param null|array  $parameters
      * @param null|string $tag
      * @param null|string $connectionAlias
@@ -74,7 +74,7 @@ public function run($query, $parameters = null, $tag = null, $connectionAlias =
                 throw $e;
             }
 
-            return;
+            return null;
         }
 
         return $result;
diff --git a/src/ClientBuilder.php b/src/ClientBuilder.php
index 8fad4011..d618f383 100644
--- a/src/ClientBuilder.php
+++ b/src/ClientBuilder.php
@@ -88,7 +88,7 @@ public function addConnection($alias, $uri, ConfigInterface $config = null)
         $this->config['connections'][$alias]['uri'] = $uri;
 
         if (null !== $config) {
-            if ($this->config['connections'][$alias]['config'] = $config);
+            $this->config['connections'][$alias]['config'] = $config;
         }
 
         return $this;
diff --git a/src/ClientInterface.php b/src/ClientInterface.php
index 420dc71c..4cf4c95c 100644
--- a/src/ClientInterface.php
+++ b/src/ClientInterface.php
@@ -27,7 +27,7 @@ interface ClientInterface
     /**
      * Run a Cypher statement against the default database or the database specified.
      *
-     * @param $query
+     * @param string      $query
      * @param null|array  $parameters
      * @param null|string $tag
      * @param null|string $connectionAlias
diff --git a/src/Connection/Connection.php b/src/Connection/Connection.php
index 89479dd0..7a363d63 100644
--- a/src/Connection/Connection.php
+++ b/src/Connection/Connection.php
@@ -174,7 +174,7 @@ private function buildDriver()
             $port = isset($params['port']) ? (int) $params['port'] : BoltDriver::DEFAULT_TCP_PORT;
             $uri = sprintf('%s://%s:%d', $params['scheme'], $params['host'], $port);
             $config = null;
-            if (isset($params['user']) && isset($params['pass'])) {
+            if (isset($params['user'], $params['pass'])) {
                 $config = BoltConfiguration::create()->withCredentials($params['user'], $params['pass']);
             }
             $this->driver = BoltGraphDB::driver($uri, $config);
diff --git a/src/Exception/Neo4jException.php b/src/Exception/Neo4jException.php
index 82ecb76c..b5efc832 100644
--- a/src/Exception/Neo4jException.php
+++ b/src/Exception/Neo4jException.php
@@ -54,7 +54,7 @@ public function classification()
     {
         $parts = explode('.', $this->statusCode);
         if (!isset($parts[1])) {
-            throw new \InvalidArgumentException(sprintf('Could not parse exception classification "%"', $this->statusCode));
+            throw new \InvalidArgumentException(sprintf('Could not parse exception classification "%s"', $this->statusCode));
         }
 
         return $parts[1];
diff --git a/src/Formatter/RecordView.php b/src/Formatter/RecordView.php
index d0f713fb..371145a5 100644
--- a/src/Formatter/RecordView.php
+++ b/src/Formatter/RecordView.php
@@ -64,6 +64,7 @@ public function hasValues()
     }
 
     /**
+     * @deprecated Use <code>get()</code> instead
      * @param string $key
      *
      * @return \GraphAware\Neo4j\Client\Formatter\Type\Node|\GraphAware\Neo4j\Client\Formatter\Type\Relationship
diff --git a/src/Formatter/Response.php b/src/Formatter/Response.php
index d419d018..3f899a92 100644
--- a/src/Formatter/Response.php
+++ b/src/Formatter/Response.php
@@ -34,11 +34,8 @@ class Response
     public function setRawResponse($rawResponse)
     {
         $this->rawResponse = $rawResponse;
-
-        if (isset($rawResponse['errors'])) {
-            if (!empty($rawResponse['errors'])) {
-                $this->errors = $rawResponse['errors'][0];
-            }
+        if (!empty($rawResponse['errors'])) {
+            $this->errors = $rawResponse['errors'][0];
         }
     }
 
diff --git a/src/Formatter/Result.php b/src/Formatter/Result.php
index f7fa7bbe..061db3de 100644
--- a/src/Formatter/Result.php
+++ b/src/Formatter/Result.php
@@ -13,7 +13,6 @@
 
 use GraphAware\Common\Cypher\StatementInterface;
 use GraphAware\Common\Result\AbstractRecordCursor;
-use GraphAware\Common\Result\Record;
 use GraphAware\Neo4j\Client\Formatter\Type\Node;
 use GraphAware\Neo4j\Client\Formatter\Type\Path;
 use GraphAware\Neo4j\Client\Formatter\Type\Relationship;
@@ -22,11 +21,6 @@
 
 class Result extends AbstractRecordCursor
 {
-    /**
-     * @var RecordView[]
-     */
-    protected $records = [];
-
     /**
      * @var string[]
      */
@@ -103,10 +97,10 @@ public function setGraph(array $graph)
     }
 
     /**
-     * @param $data
-     * @param $graph
+     * @param array $data
+     * @param array $graph
      */
-    public function pushRecord($data, $graph)
+    public function pushRecord(array $data, array $graph)
     {
         $mapped = $this->array_map_deep($data, $graph);
         $this->records[] = new RecordView($this->fields, $mapped);
diff --git a/src/HttpDriver/Configuration.php b/src/HttpDriver/Configuration.php
index 3890d816..aa4848ba 100644
--- a/src/HttpDriver/Configuration.php
+++ b/src/HttpDriver/Configuration.php
@@ -36,6 +36,8 @@ class Configuration extends BaseConfiguration implements ConfigInterface
     protected $curlInterface;
 
     /**
+     * @param HttpClient|null $httpClient
+     * @param RequestFactory|null $requestFactory
      * @return Configuration
      */
     public static function create(HttpClient $httpClient = null, RequestFactory $requestFactory = null)
diff --git a/src/HttpDriver/Driver.php b/src/HttpDriver/Driver.php
index 8aa34ba9..dbbe21af 100644
--- a/src/HttpDriver/Driver.php
+++ b/src/HttpDriver/Driver.php
@@ -36,10 +36,6 @@ class Driver implements DriverInterface
      */
     public function __construct($uri, ConfigInterface $config = null)
     {
-        if (null !== $config && !$config instanceof BaseConfiguration) {
-            throw new \RuntimeException(sprintf('Second argument to "%s" must be null or "%s"', __CLASS__, BaseConfiguration::class));
-        }
-
         $this->uri = $uri;
         $this->config = null !== $config ? $config : Configuration::create();
     }
diff --git a/src/HttpDriver/Result/ResultSummary.php b/src/HttpDriver/Result/ResultSummary.php
index 16984c21..fddc7689 100644
--- a/src/HttpDriver/Result/ResultSummary.php
+++ b/src/HttpDriver/Result/ResultSummary.php
@@ -26,6 +26,9 @@ class ResultSummary implements ResultSummaryInterface
      */
     protected $updateStatistics;
 
+    /**
+     * @var array
+     */
     protected $notifications;
 
     protected $type;
diff --git a/src/HttpDriver/Result/StatementStatistics.php b/src/HttpDriver/Result/StatementStatistics.php
index c72aa103..be4acba7 100644
--- a/src/HttpDriver/Result/StatementStatistics.php
+++ b/src/HttpDriver/Result/StatementStatistics.php
@@ -192,7 +192,7 @@ public function constraintsRemoved()
     }
 
     /**
-     * @param $key
+     * @param string $key
      *
      * @return string
      */
diff --git a/src/HttpDriver/Session.php b/src/HttpDriver/Session.php
index 25026c4d..cacfbf0d 100644
--- a/src/HttpDriver/Session.php
+++ b/src/HttpDriver/Session.php
@@ -66,7 +66,7 @@ class Session implements SessionInterface
     public function __construct($uri, $httpClient, ConfigInterface $config)
     {
         if ($httpClient instanceof GuzzleClient) {
-            @trigger_error('Passing a Guzzle client to Session is deprecrated. Will be removed in 5.0. Use a HTTPlug client');
+            @trigger_error('Passing a Guzzle client to Session is deprecated. Will be removed in 5.0. Use a HTTPlug client', E_USER_DEPRECATED);
             $httpClient = new Client($httpClient);
         } elseif (!$httpClient instanceof HttpClient) {
             throw new \RuntimeException('Second argument to Session::__construct must be an instance of Http\Client\HttpClient.');
diff --git a/src/Stack.php b/src/Stack.php
index 3e5b71b9..bc7787f7 100644
--- a/src/Stack.php
+++ b/src/Stack.php
@@ -41,12 +41,14 @@ class Stack implements StackInterface
     protected $hasWrites = false;
 
     /**
-     * @param null        $tag
+     * @param null|string $tag
      * @param null|string $connectionAlias
      */
     public function __construct($tag = null, $connectionAlias = null)
     {
-        $this->tag = null !== $tag ? (string) $tag : null;
+	if (null !== $tag) {
+            $this->tag = (string)$tag;
+        }
         $this->connectionAlias = $connectionAlias;
     }
 
@@ -85,7 +87,7 @@ public function pushWrite($query, $parameters = null, $tag = null)
     }
 
     /**
-     * @param $query
+     * @param string $query
      * @param array|null $parameters
      * @param array|null $tag
      */
diff --git a/src/StackInterface.php b/src/StackInterface.php
index db591c38..8dc8cb7d 100644
--- a/src/StackInterface.php
+++ b/src/StackInterface.php
@@ -41,7 +41,7 @@ public function push($query, $parameters = null, $tag = null);
     public function pushWrite($query, $parameters = null, $tag = null);
 
     /**
-     * @param $query
+     * @param string     $query
      * @param array|null $parameters
      * @param array|null $tag
      */