diff --git a/src/bin/printmap.rs b/src/bin/printmap.rs
index ed2a4fd..b233e0b 100644
--- a/src/bin/printmap.rs
+++ b/src/bin/printmap.rs
@@ -40,6 +40,7 @@ fn main() {
   print_rows(world.map().rows());
 }
 
+#[allow(unstable_name_collisions)]
 fn print_rows<'a, T: ?Sized, U: ?Sized>(rows: Box<T>)
   where T: Iterator<Item = Box<U>> + 'a,
         U: Iterator<Item = &'a tile::Tile> + 'a