diff --git a/external-crates/move/crates/move-bytecode-utils/src/lib.rs b/external-crates/move/crates/move-bytecode-utils/src/lib.rs
index c2af29e185dd64..456ef27c2fb800 100644
--- a/external-crates/move/crates/move-bytecode-utils/src/lib.rs
+++ b/external-crates/move/crates/move-bytecode-utils/src/lib.rs
@@ -25,10 +25,12 @@ impl<'a> Modules<'a> {
     pub fn new(modules: impl IntoIterator<Item = &'a CompiledModule>) -> Self {
         let mut map = BTreeMap::new();
         for m in modules {
-            assert!(
-                map.insert(m.self_id(), m).is_none(),
-                "Duplicate module found"
-            );
+            if let Some(prev) = map.insert(m.self_id(), m) {
+                panic!(
+                    "Duplicate module found: {}",
+                    prev.self_id().to_canonical_display(/* with_prefix */ true)
+                )
+            }
         }
         Modules(map)
     }