diff --git a/src/vector2d.rs b/src/vector2d.rs
index b7ef0c0..28e7435 100644
--- a/src/vector2d.rs
+++ b/src/vector2d.rs
@@ -33,7 +33,7 @@ where
     &v[y][x]
 }
 
-pub fn in_range<T, U>(v: &Vec<Vec<U>>, idx: &Vector2D<T>) -> bool
+pub fn in_range<T, U>(v: &[Vec<U>], idx: &Vector2D<T>) -> bool
 where
     usize: TryInto<T>,
     <usize as TryInto<T>>::Error: Debug,