From a3344d1a3aef9d8c1171899fcd34486a7038a984 Mon Sep 17 00:00:00 2001
From: Josh Stone <jistone@redhat.com>
Date: Mon, 1 Jun 2020 17:47:26 -0700
Subject: [PATCH] Add a test to ensure Fuse stays covariant

---
 src/test/ui/variance-iterators-in-libcore.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/test/ui/variance-iterators-in-libcore.rs b/src/test/ui/variance-iterators-in-libcore.rs
index 2ab3a8ab5c129..a542e44d517a7 100644
--- a/src/test/ui/variance-iterators-in-libcore.rs
+++ b/src/test/ui/variance-iterators-in-libcore.rs
@@ -1,9 +1,10 @@
 // run-pass
 
-#![allow(warnings)]
+#![allow(dead_code)]
 
-use std::iter::Zip;
+use std::iter::{Fuse, Zip};
 
+fn fuse_covariant<'a, I>(iter: Fuse<&'static I>) -> Fuse<&'a I> { iter }
 fn zip_covariant<'a, A, B>(iter: Zip<&'static A, &'static B>) -> Zip<&'a A, &'a B> { iter }
 
 fn main() { }