Add wrapper to prevent iteration of unordered maps
diff --git a/syntax/instantiate.rs b/syntax/instantiate.rs
index 2891485..e9c6f29 100644
--- a/syntax/instantiate.rs
+++ b/syntax/instantiate.rs
@@ -1,7 +1,7 @@
 use crate::syntax::Type;
 use proc_macro2::Ident;
 
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
 pub enum ImplKey<'a> {
     RustBox(&'a Ident),
     RustVec(&'a Ident),