diff --git a/implementations/rust/preserves/src/lib.rs b/implementations/rust/preserves/src/lib.rs
index 54338eb..54c8ca1 100644
--- a/implementations/rust/preserves/src/lib.rs
+++ b/implementations/rust/preserves/src/lib.rs
@@ -11,7 +11,7 @@ pub mod value;
 #[cfg(test)]
 mod dom {
     use super::value::{
-        Value, IOValue, IOResult, NestedValue, PlainValue, Domain,
+        Value, IOValue, IOResult, NestedValue, PlainValue, PreDomain, Domain,
         PackedWriter,
     };
 
@@ -21,7 +21,8 @@ mod dom {
         Two,
     }
 
-    impl Domain for Dom {
+    impl Domain for Dom {}
+    impl PreDomain for Dom {
         fn from_preserves(v: IOValue) -> IOResult<Self> {
             panic!("Cannot decode IOValue to Dom: {:?}", v);
         }
diff --git a/implementations/rust/preserves/src/value/mod.rs b/implementations/rust/preserves/src/value/mod.rs
index c612d18..6c20177 100644
--- a/implementations/rust/preserves/src/value/mod.rs
+++ b/implementations/rust/preserves/src/value/mod.rs
@@ -22,6 +22,7 @@ pub use repr::IOValue;
 pub use repr::Map;
 pub use repr::NestedValue;
 pub use repr::PlainValue;
+pub use repr::PreDomain;
 pub use repr::RcValue;
 pub use repr::Record;
 pub use repr::Set;
diff --git a/implementations/rust/preserves/src/value/repr.rs b/implementations/rust/preserves/src/value/repr.rs
index ecb5a77..a470090 100644
--- a/implementations/rust/preserves/src/value/repr.rs
+++ b/implementations/rust/preserves/src/value/repr.rs
@@ -21,12 +21,15 @@ use super::IOResult;
 use super::signed_integer::SignedInteger;
 use crate::error::{Error, ExpectedKind, Received};
 
-pub trait Domain: Sized + Debug + Clone + Eq + Hash + Ord {
+pub trait PreDomain: Sized + Debug + Eq + Hash + Ord {
     fn from_preserves(v: IOValue) -> IOResult<Self>;
     fn as_preserves(&self) -> IOValue;
 }
 
-impl<D: Domain> Domain for Arc<D> {
+pub trait Domain: PreDomain + Clone {}
+
+impl<D: PreDomain> Domain for Arc<D> {}
+impl<D: PreDomain> PreDomain for Arc<D> {
     fn from_preserves(v: IOValue) -> IOResult<Self> {
         Ok(Arc::new(D::from_preserves(v)?))
     }
@@ -1109,7 +1112,8 @@ impl<'de, Dom: Domain> serde::Deserialize<'de> for ArcValue<Dom> {
 pub struct IOValue(Arc<AnnotatedValue<IOValue, IOValue>>);
 pub type UnwrappedIOValue = Value<IOValue, IOValue>;
 
-impl Domain for IOValue {
+impl Domain for IOValue {}
+impl PreDomain for IOValue {
     fn from_preserves(v: IOValue) -> IOResult<Self> {
         Ok(v)
     }