1 files changed, 4 insertions, 1 deletions
diff --git a/compiler/rustc_monomorphize/src/lib.rs b/compiler/rustc_monomorphize/src/lib.rs
index caae54cd559..714b64b3a23 100644
--- a/compiler/rustc_monomorphize/src/lib.rs
+++ b/compiler/rustc_monomorphize/src/lib.rs
@@ -42,7 +42,10 @@ fn custom_coerce_unsize_info<'tcx>(
             ..
         })) => Ok(tcx.coerce_unsized_info(impl_def_id)?.custom_kind.unwrap()),
         impl_source => {
-            bug!("invalid `CoerceUnsized` impl_source: {:?}", impl_source);
+            bug!(
+                "invalid `CoerceUnsized` from {source_ty} to {target_ty}: impl_source: {:?}",
+                impl_source
+            );
         }
     }
 }