diff --git a/Cargo.toml b/Cargo.toml
index 81a1e64a..a044bc86 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -67,6 +67,7 @@ unsafe_code = "forbid"
 cloned_instead_of_copied = "warn"
 explicit_iter_loop = "warn"
 implicit_clone = "warn"
+inefficient_to_string = "warn"
 missing_const_for_fn = "warn"
 needless_for_each = "warn"
 semicolon_if_nothing_returned = "warn"
diff --git a/src/widgets/list.rs b/src/widgets/list.rs
index 8456eccf..cb765407 100755
--- a/src/widgets/list.rs
+++ b/src/widgets/list.rs
@@ -1197,7 +1197,7 @@ mod tests {
 
     /// helper method to take a vector of strings and return a vector of list items
     fn list_items(items: Vec<&str>) -> Vec<ListItem> {
-        items.iter().map(|i| ListItem::new(i.to_string())).collect()
+        items.into_iter().map(ListItem::new).collect()
     }
 
     /// helper method to render a widget to an empty buffer with the default state