cs: Switch to a stricter way of coding - this might break in a lot of places.

src/Bundle/ChillPersonBundle/Entity/AccompanyingPeriodParticipation.php

@@ -7,6 +7,15 @@
  * the LICENSE file that was distributed with this source code.
  */
 
+declare(strict_types=1);
+
+/**
+ * Chill is a software for social workers.
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
 namespace Chill\PersonBundle\Entity;
 
 use DateTimeImmutable;
@@ -123,7 +132,7 @@ class AccompanyingPeriodParticipation
 
     private function checkSameStartEnd()
     {
-        if ($this->endDate == $this->startDate) {
+        if ($this->endDate === $this->startDate) {
             $this->accompanyingPeriod->removeParticipation($this);
         }
     }