diff --git a/lib/Analytics/Analytics.php b/lib/Analytics/Analytics.php
index 956df5b06e..0cec95f423 100644
--- a/lib/Analytics/Analytics.php
+++ b/lib/Analytics/Analytics.php
@@ -27,13 +27,14 @@ class Analytics {
     $this->wp = new WPFunctions;
   }
 
-  /** @return array */
+  /** @return array|null */
   function generateAnalytics() {
     if ($this->shouldSend()) {
       $data = $this->wp->applyFilters(self::ANALYTICS_FILTER, $this->reporter->getData());
       $this->recordDataSent();
       return $data;
     }
+    return null;
   }
 
   /** @return boolean */
diff --git a/lib/Config/MP2Migrator.php b/lib/Config/MP2Migrator.php
index 2898161184..ec6338c5d8 100644
--- a/lib/Config/MP2Migrator.php
+++ b/lib/Config/MP2Migrator.php
@@ -770,7 +770,7 @@ class MP2Migrator {
    * Import a subscriber custom field
    *
    * @param int $subscriber_id Subscriber ID
-   * @param int $custom_field Custom field
+   * @param array $custom_field Custom field
    * @param string $custom_field_value Custom field value
    * @return SubscriberCustomField
    */
diff --git a/lib/Doctrine/MetadataCache.php b/lib/Doctrine/MetadataCache.php
index b8491ed9f7..fe0cda7783 100644
--- a/lib/Doctrine/MetadataCache.php
+++ b/lib/Doctrine/MetadataCache.php
@@ -60,10 +60,12 @@ class MetadataCache extends CacheProvider {
     if ($result === false) {
       throw new \RuntimeException("Error while writing to '$filename'");
     }
+    return true;
   }
 
   protected function doDelete($id) {
     @unlink($this->getFilename($id));
+    return true;
   }
 
   protected function doFlush() {
@@ -72,6 +74,7 @@ class MetadataCache extends CacheProvider {
         @unlink($filename);
       }
     }
+    return true;
   }
 
   protected function doGetStats() {
diff --git a/lib/Entities/NewsletterEntity.php b/lib/Entities/NewsletterEntity.php
index 4ecf5b5303..6dfce83d69 100644
--- a/lib/Entities/NewsletterEntity.php
+++ b/lib/Entities/NewsletterEntity.php
@@ -342,8 +342,8 @@ class NewsletterEntity {
       }
     } catch (EntityNotFoundException $enf) {
       $this->setParent(null);
-      return null;
     }
+    return null;
   }
 
   /**
diff --git a/lib/Models/ScheduledTask.php b/lib/Models/ScheduledTask.php
index f4f5abd984..28d42e4328 100644
--- a/lib/Models/ScheduledTask.php
+++ b/lib/Models/ScheduledTask.php
@@ -126,6 +126,7 @@ class ScheduledTask extends Model {
       ORM::get_db()->rollBack();
       throw $error;
     }
+    return null;
   }
 
   function rescheduleProgressively() {
diff --git a/lib/Models/Subscriber.php b/lib/Models/Subscriber.php
index 1e54378989..0de4eca92b 100644
--- a/lib/Models/Subscriber.php
+++ b/lib/Models/Subscriber.php
@@ -89,6 +89,7 @@ class Subscriber extends Model {
       SubscriberCustomField::deleteSubscriberRelations($this);
       return parent::delete();
     }
+    return null;
   }
 
   function trash() {
diff --git a/lib/Tracy/ApiPanel/ApiPanel.php b/lib/Tracy/ApiPanel/ApiPanel.php
index a2c35b5f22..66681e9c43 100644
--- a/lib/Tracy/ApiPanel/ApiPanel.php
+++ b/lib/Tracy/ApiPanel/ApiPanel.php
@@ -42,7 +42,7 @@ class ApiPanel implements IBarPanel {
   }
 
   static function init($endpoint, $request_method, $request_data) {
-    Debugger::getBar()->addPanel(new static($endpoint, $request_method, $request_data));
+    Debugger::getBar()->addPanel(new ApiPanel($endpoint, $request_method, $request_data));
   }
 
   private function getEndpointName() {
diff --git a/lib/Tracy/DIPanel/DIPanel.php b/lib/Tracy/DIPanel/DIPanel.php
index e755b2ff21..cf066e8dc9 100644
--- a/lib/Tracy/DIPanel/DIPanel.php
+++ b/lib/Tracy/DIPanel/DIPanel.php
@@ -38,7 +38,7 @@ class DIPanel implements IBarPanel {
   }
 
   static function init() {
-    Debugger::getBar()->addPanel(new static());
+    Debugger::getBar()->addPanel(new DIPanel());
   }
 
   private function loadServices() {
diff --git a/lib/Tracy/DoctrinePanel/DoctrinePanel.php b/lib/Tracy/DoctrinePanel/DoctrinePanel.php
index 0e9883c44e..cd2412a419 100644
--- a/lib/Tracy/DoctrinePanel/DoctrinePanel.php
+++ b/lib/Tracy/DoctrinePanel/DoctrinePanel.php
@@ -41,7 +41,7 @@ class DoctrinePanel implements IBarPanel {
   }
 
   static function init(EntityManagerInterface $entity_manager) {
-    Debugger::getBar()->addPanel(new static($entity_manager->getConnection()->getConfiguration()));
+    Debugger::getBar()->addPanel(new DoctrinePanel($entity_manager->getConnection()->getConfiguration()));
   }
 
   protected function formatSql($sql) {