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src/HOL/Tools/BNF/bnf_gfp_rec_sugar.ML
changeset 59042 ef0074e812cd
parent 59041 2a23235632b2
child 59043 a00110bdb4a3 
--- a/src/HOL/Tools/BNF/bnf_gfp_rec_sugar.ML	Mon Nov 24 12:35:13 2014 +0100
+++ b/src/HOL/Tools/BNF/bnf_gfp_rec_sugar.ML	Mon Nov 24 12:35:13 2014 +0100
@@ -696,7 +696,7 @@
 
     val disc_concl = betapply (disc, lhs);
     val (eqn_data_disc_opt, matchedsss') =
-      if null (tl basic_ctr_specs) then
+      if null (tl basic_ctr_specs) andalso not (null sels) then
         (NONE, matchedsss)
       else
         apfst SOME (dissect_coeqn_disc lthy fun_names sequentials basic_ctr_specss eqn_pos
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