Fixed some incompatibility on PHP 7.4

src/Form/Type/CurrencyEntityType.php

@@ -79,6 +79,10 @@ class CurrencyEntityType extends StructuralEntityType
     {
         $tmp = parent::generateChoiceAttr($choice, $key, $value, $options);
 
+        if (!$choice instanceof Currency) {
+            throw new RuntimeException('The choice must be an instance of '.Currency::class);
+        }
+
         if(!empty($choice->getIsoCode())) {
             $symbol = Currencies::getSymbol($choice->getIsoCode());
         } else {

src/Repository/StructuralDBElementRepository.php

@@ -111,8 +111,9 @@ class StructuralDBElementRepository extends NamedDBElementRepository
             //See if we already have an element with this name and parent
             $entity = $this->findOneBy(['name' => $name, 'parent' => $parent]);
             if (null === $entity) {
+                $class = $this->getClassName();
                 /** @var AbstractStructuralDBElement $entity */
-                $entity = new ($this->getClassName());
+                $entity = new $class;
                 $entity->setName($name);
                 $entity->setParent($parent);
             }