diff --git a/src/solvers/flattening/boolbv_width.cpp b/src/solvers/flattening/boolbv_width.cpp
index 3eb86287ba4..1be31bf350a 100644
--- a/src/solvers/flattening/boolbv_width.cpp
+++ b/src/solvers/flattening/boolbv_width.cpp
@@ -222,7 +222,10 @@ const boolbv_widtht::entryt &boolbv_widtht::get_entry(const typet &type) const
     cache_entry = defined_entryt{0};
   }
   else
-    UNIMPLEMENTED;
+  {
+    UNIMPLEMENTED_FEATURE(
+      "boolbv_widtht::get_entry(" + id2string(type_id) + ")");
+  }
 
   return cache_entry;
 }