diff --git a/src/flatten_ok.rs b/src/flatten_ok.rs
index 21ae1f722..853122295 100644
--- a/src/flatten_ok.rs
+++ b/src/flatten_ok.rs
@@ -147,13 +147,7 @@ where
     T: IntoIterator,
     T::IntoIter: fmt::Debug,
 {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("FlattenOk")
-            .field("iter", &self.iter)
-            .field("inner_front", &self.inner_front)
-            .field("inner_back", &self.inner_back)
-            .finish()
-    }
+    debug_fmt_fields!(FlattenOk, iter, inner_front, inner_back);
 }
 
 /// Only the iterator being flattened needs to implement [`FusedIterator`].