diff --git a/src/hugr/rewrite/consts.rs b/src/hugr/rewrite/consts.rs
index f00b67cb0..d8a0060b7 100644
--- a/src/hugr/rewrite/consts.rs
+++ b/src/hugr/rewrite/consts.rs
@@ -6,6 +6,7 @@ use crate::{
     hugr::{HugrError, HugrMut},
     HugrView, Node,
 };
+#[rustversion::since(1.75)] // uses impl in return position
 use itertools::Itertools;
 use thiserror::Error;
 
@@ -32,6 +33,7 @@ pub enum RemoveConstIgnoreError {
     RemoveFail(#[from] HugrError),
 }
 
+#[rustversion::since(1.75)] // uses impl in return position
 impl Rewrite for RemoveConstIgnore {
     type Error = RemoveConstIgnoreError;
 
@@ -134,6 +136,7 @@ impl Rewrite for RemoveConst {
     }
 }
 
+#[rustversion::since(1.75)] // uses impl in return position
 #[cfg(test)]
 mod test {
     use super::*;