src/HOL/Tools/TFL/casesplit.ML

     let
       val ty_str = case ty of
                      Type(ty_str, _) => ty_str
                    | TFree(s,_)  => error ("Free type: " ^ s)
                    | TVar((s,i),_) => error ("Free variable: " ^ s)
-      val {induct, ...} = Datatype.the_info thy ty_str
+      val {induct, ...} = Datatype_Data.the_info thy ty_str
     in
       cases_thm_of_induct_thm induct
     end;