symfony
diff --git a/‎src/Symfony/Component/DependencyInjection/Compiler/PriorityTaggedServiceTrait.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/DependencyInjection/Compiler/PriorityTaggedServiceTrait.php
+4Lines changed: 4 additions & 0 deletions b/‎src/Symfony/Component/DependencyInjection/Compiler/PriorityTaggedServiceTrait.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/DependencyInjection/Compiler/PriorityTaggedServiceTrait.php
+4Lines changed: 4 additions & 0 deletions
diff --git a/‎src/Symfony/Component/DependencyInjection/Tests/Compiler/PriorityTaggedServiceTraitTest.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/DependencyInjection/Tests/Compiler/PriorityTaggedServiceTraitTest.php
+8Lines changed: 8 additions & 0 deletions b/‎src/Symfony/Component/DependencyInjection/Tests/Compiler/PriorityTaggedServiceTraitTest.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/DependencyInjection/Tests/Compiler/PriorityTaggedServiceTraitTest.php
+8Lines changed: 8 additions & 0 deletions
@@ -133,6 +133,10 @@ public static function getDefault(ContainerBuilder $container, string $serviceId
             return null;
         }
 
+        if ($r->isInterface()) {
+            return null;
+        }
+
         if (null !== $indexAttribute) {
             $service = $class !== $serviceId ? sprintf('service "%s"', $serviceId) : 'on the corresponding service';
             $message = [sprintf('Either method "%s::%s()" should ', $class, $defaultMethod), sprintf(' or tag "%s" on %s is missing attribute "%s".', $tagName, $service, $indexAttribute)];
 
@@ -151,13 +151,16 @@ public function testTheIndexedTagsByDefaultIndexMethod()
 
         $container->register('service3', IntTagClass::class)->addTag('my_custom_tag');
 
+        $container->register('service4', HelloInterface::class)->addTag('my_custom_tag');
+
         $priorityTaggedServiceTraitImplementation = new PriorityTaggedServiceTraitImplementation();
 
         $tag = new TaggedIteratorArgument('my_custom_tag', 'foo', 'getFooBar');
         $expected = [
             'bar_tab_class_with_defaultmethod' => new TypedReference('service2', BarTagClass::class),
             'service1' => new TypedReference('service1', FooTagClass::class),
             '10' => new TypedReference('service3', IntTagClass::class),
+            'service4' => new TypedReference('service4', HelloInterface::class),
         ];
         $services = $priorityTaggedServiceTraitImplementation->test($tag, $container);
         $this->assertSame(array_keys($expected), array_keys($services));
@@ -244,3 +247,8 @@ class HelloNamedService extends \stdClass
 class HelloNamedService2
 {
 }
+
+interface HelloInterface
+{
+    public static function getFooBar(): string;
+}