src/HOL/Tools/Nitpick/nitpick.ML

         ()
     (* This detection code is an ugly hack. Fortunately, it is used only to
        provide a hint to the user. *)
     fun is_struct_induct_step (name, (Rule_Cases.Case {fixes, assumes, ...}, _)) =
       not (null fixes) andalso
-      exists (String.isSuffix ".hyps" o fst) assumes andalso
+      exists (String.isSuffix ".hyps" o Name_Space.full_name Name_Space.default_naming o fst) assumes andalso
       exists (exists (curry (op =) name o shortest_name o fst)
               o datatype_constrs hol_ctxt) deep_dataTs
     val likely_in_struct_induct_step =
       exists is_struct_induct_step (Proof_Context.dest_cases ctxt)
     val _ = if standard andalso likely_in_struct_induct_step then