src/HOL/Tools/record.ML

     val algebra = Sign.classes_of thy;
     val has_inst = can (Sorts.mg_domain algebra ext_tyco) @{sort random};
   in
     if has_inst then thy
     else
-      (case Random_Generators.perhaps_constrain thy (map (rpair @{sort random}) Ts) vs of
+      (case Quickcheck_Common.perhaps_constrain thy (map (rpair @{sort random}) Ts) vs of
         SOME constrain =>
           instantiate_random_record ext_tyco (map constrain vs) extN
             ((map o map_atyps) (fn TFree v => TFree (constrain v)) Ts) thy
       | NONE => thy)
   end;