diff --git a/implementations/rust/src/value/de.rs b/implementations/rust/src/value/de.rs
index 7c8de0e..7b1f12e 100644
--- a/implementations/rust/src/value/de.rs
+++ b/implementations/rust/src/value/de.rs
@@ -38,12 +38,6 @@ pub mod error {
         Dictionary,
     }
 
-    impl<D: Domain> serde::ser::Error for Error<D> {
-        fn custom<T: std::fmt::Display>(msg: T) -> Self {
-            Self::Message(msg.to_string())
-        }
-    }
-
     impl<D: Domain> serde::de::Error for Error<D> {
         fn custom<T: std::fmt::Display>(msg: T) -> Self {
             Self::Message(msg.to_string())