src/Tools/Code/code_preproc.ML

     val vs' = Term.add_tfrees t' [];
     val consts = fold_aterms
       (fn Const (c, _) => insert (op =) c | _ => I) t' [];
     val (algebra', eqngr') = obtain false thy consts [t'];
   in
-    evaluator algebra' eqngr' vs' t'
+    t'
+    |> evaluator algebra' eqngr' vs'
     |> postproc (postprocess_term thy o resubst)
   end;
 
 fun static_eval_conv thy consts conv =
   let