diff --git a/crates/compiler/load_internal/src/work.rs b/crates/compiler/load_internal/src/work.rs
index b0e5b2c8ce..6c2226f6cb 100644
--- a/crates/compiler/load_internal/src/work.rs
+++ b/crates/compiler/load_internal/src/work.rs
@@ -64,7 +64,8 @@ impl MakeSpecializationsDependents {
         let entry = self.entry(module_id);
         debug_assert!(
             entry.succ.is_empty(),
-            "already added successors for this module"
+            "already added successors for module '{:?}'",
+            module_id
         );
 
         entry.succ.extend(succ.into_iter());