diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index 7284c05d5ff..f7d68b5a89e 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -25,6 +25,8 @@
 #![feature(string_remove_matches)]
 #![feature(const_btree_new)]
 #![feature(const_trait_impl)]
+// FIXME remove this when const_trait_impl is not incomplete anymore
+#![allow(incomplete_features)]
 
 use std::collections::hash_map::DefaultHasher;
 use std::hash::{Hash, Hasher};