diff --git a/fj-kernel/src/shape/stores.rs b/fj-kernel/src/shape/stores.rs
index a612d8d64..905289bea 100644
--- a/fj-kernel/src/shape/stores.rs
+++ b/fj-kernel/src/shape/stores.rs
@@ -28,7 +28,7 @@ pub struct Stores {
 }
 
 impl Stores {
-    pub fn get<T>(&mut self) -> Store<T>
+    pub fn get<T>(&self) -> Store<T>
     where
         T: Object,
     {