Index: iddqd/Cargo.toml
===================================================================
--- iddqd.orig/Cargo.toml
+++ iddqd/Cargo.toml
@@ -151,7 +151,7 @@ version = "1.0.24"
 optional = true
 
 [dependencies.rustc-hash]
-version = "2.1.1"
+version = "1.1.0"
 default-features = false
 
 [dependencies.schemars]
Index: iddqd/src/support/item_set.rs
===================================================================
--- iddqd.orig/src/support/item_set.rs
+++ iddqd/src/support/item_set.rs
@@ -8,7 +8,9 @@ use core::{
     ops::{Index, IndexMut},
 };
 use hashbrown::{HashMap, hash_map};
-use rustc_hash::FxBuildHasher;
+use core::hash::BuildHasherDefault;
+use rustc_hash::FxHasher;
+type FxBuildHasher = BuildHasherDefault<FxHasher>;
 
 /// A map of items stored by integer index.
 #[derive(Clone)]
@@ -42,7 +44,7 @@ impl<T, A: Allocator> ItemSet<T, A> {
     #[inline]
     pub(crate) const fn new_in(alloc: A) -> Self {
         Self {
-            items: HashMap::with_hasher_in(FxBuildHasher, AllocWrapper(alloc)),
+            items: HashMap::with_hasher_in(FxBuildHasher::new(), AllocWrapper(alloc)),
             next_index: 0,
         }
     }
