diff --git a/src/commands.rs b/src/commands.rs
index 2aafcbe..4658e3d 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -711,7 +711,7 @@ fn smart_unpack(
 
 fn check_mime_type(
     files: &[PathBuf],
-    formats: &mut Vec<Vec<Extension>>,
+    formats: &mut [Vec<Extension>],
     question_policy: QuestionPolicy,
 ) -> crate::Result<ControlFlow<()>> {
     for (path, format) in files.iter().zip(formats.iter_mut()) {