src/HOL/Tools/Predicate_Compile/core_data.ML

 fun needs_random ctxt s m =
   member (op =) (#needs_random (the_pred_data ctxt s)) m
 
 fun lookup_predfun_data ctxt name mode =
   Option.map rep_predfun_data
-    (AList.lookup (op =) (#predfun_data (the_pred_data ctxt name)) mode)
+    (AList.lookup eq_mode (#predfun_data (the_pred_data ctxt name)) mode)
 
 fun the_predfun_data ctxt name mode =
   case lookup_predfun_data ctxt name mode of
     NONE => error ("No function defined for mode " ^ string_of_mode mode ^
       " of predicate " ^ name)