diff --git a/src/printf/tokenize/sub.rs b/src/printf/tokenize/sub.rs
index 438fdbedc..5ef5578c5 100644
--- a/src/printf/tokenize/sub.rs
+++ b/src/printf/tokenize/sub.rs
@@ -292,8 +292,8 @@ impl SubParser {
                 }
             }
         } else {
-            n_ch.map(|x| it.put_back(x));
-            preface.map(|x| it.put_back(x));
+            if let Some(x) = n_ch { it.put_back(x) };
+            if let Some(x) = preface { it.put_back(x) };
             false
         }
     }