Disable CollectionRef tests on too-old features

diff --git a/rust-bindings/rust/src/tests/collection_ref.rs b/rust-bindings/rust/src/tests/collection_ref.rs
index 9db3177aaee007b4a8e4b8dad67d72670528f5f4..b6bf050e6b17c63ef8105ea3d3a85f2c26f0bb1c 100644 (file)
--- a/rust-bindings/rust/src/tests/collection_ref.rs
+++ b/rust-bindings/rust/src/tests/collection_ref.rs
@@ -1,3 +1,5 @@
+#![cfg(feature = "v2018_6")]
+
 use crate::CollectionRef;
 use std::collections::hash_map::DefaultHasher;
 use std::hash::{Hash, Hasher};