diff --git a/src/CustomMapper/Implementation/PropertyMapperResolver.php b/src/CustomMapper/Implementation/PropertyMapperResolver.php
index 6753958..3fb70a5 100644
--- a/src/CustomMapper/Implementation/PropertyMapperResolver.php
+++ b/src/CustomMapper/Implementation/PropertyMapperResolver.php
@@ -66,7 +66,12 @@ public function getPropertyMapper(
             }
         } while ($sourceClassReflection = $sourceClassReflection->getParentClass());
 
-        foreach (class_implements($targetClass) as $interface) {
+        $interfaces = class_implements($sourceClass);
+        if ($interfaces === false) {
+            return null;
+        }
+
+        foreach ($interfaces as $interface) {
             if (isset($propertyMappers[$interface])) {
                 return $propertyMappers[$interface];
             }
diff --git a/src/CustomMapper/ObjectMapperTable.php b/src/CustomMapper/ObjectMapperTable.php
index 6fe191c..e22ddaf 100644
--- a/src/CustomMapper/ObjectMapperTable.php
+++ b/src/CustomMapper/ObjectMapperTable.php
@@ -73,7 +73,12 @@ public function getObjectMapper(
             }
         } while ($sourceClassReflection = $sourceClassReflection->getParentClass());
 
-        foreach (class_implements($targetClass) as $interface) {
+        $interfaces = class_implements($sourceClass);
+        if ($interfaces === false) {
+            return null;
+        }
+
+        foreach ($interfaces as $interface) {
             if (isset($propertyMappers[$interface])) {
                 return $propertyMappers[$interface];
             }
diff --git a/src/Util/TypeUtil.php b/src/Util/TypeUtil.php
index 5a00978..1b8e7ee 100644
--- a/src/Util/TypeUtil.php
+++ b/src/Util/TypeUtil.php
@@ -416,11 +416,21 @@ private static function getAllClassesFromObject(
         $class = is_object($objectOrClass) ? $objectOrClass::class : $objectOrClass;
         $classes[] = $class;
 
-        foreach (class_parents($class) as $parentClass) {
+        $parents = class_parents($class);
+        if ($parents === false) {
+            $parents = [];
+        }
+
+        foreach ($parents as $parentClass) {
             $classes[] = $parentClass;
         }
 
-        foreach (class_implements($class) as $interface) {
+        $interfaces = class_implements($class);
+        if ($interfaces === false) {
+            $interfaces = [];
+        }
+
+        foreach ($interfaces as $interface) {
             $classes[] = $interface;
         }