diff --git a/components/script/document_loader.rs b/components/script/document_loader.rs
index 4a6307667f1..9fe42e30147 100644
--- a/components/script/document_loader.rs
+++ b/components/script/document_loader.rs
@@ -130,7 +130,7 @@ impl DocumentLoader {
     pub fn finish_load(&mut self, load: &LoadType) {
         debug!("Removing blocking load {:?} ({}).", load, self.blocking_loads.len());
         let idx = self.blocking_loads.iter().position(|unfinished| *unfinished == *load);
-        self.blocking_loads.remove(idx.expect(&format!("unknown completed load {:?}", load)));
+        self.blocking_loads.remove(idx.unwrap_or_else(|| panic!("unknown completed load {:?}", load)));
     }
 
     pub fn is_blocked(&self) -> bool {