src/HOL/Mutabelle/Mutabelle.thy

   (@{const_name HOL.undefined}, "'a"),
   (@{const_name HOL.default}, "'a"),
   (@{const_name dummy_pattern}, "'a::{}"),
   (@{const_name Algebras.uminus}, "'a"),
   (@{const_name Nat.size}, "'a"),
-  (@{const_name Algebras.abs}, "'a")];
+  (@{const_name Groups.abs}, "'a")];
 
 val forbidden_thms =
  ["finite_intvl_succ_class",
   "nibble"];