diff -r d35e0fdb70f6 -r 31717e1436cd rust/vec2d/src/lib.rs
--- a/rust/vec2d/src/lib.rs	Fri Nov 30 17:09:08 2018 +0100
+++ b/rust/vec2d/src/lib.rs	Fri Nov 30 22:37:29 2018 +0300
@@ -87,13 +87,13 @@
 
     #[inline]
     pub fn rows(&self) -> impl DoubleEndedIterator<Item = &[T]> {
-        self.data.chunks(self.width())
+        self.data.chunks_exact(self.width())
     }
 
     #[inline]
     pub fn rows_mut(&mut self) -> impl DoubleEndedIterator<Item = &mut [T]> {
         let width = self.width();
-        self.data.chunks_mut(width)
+        self.data.chunks_exact_mut(width)
     }
 }