diff options
| -rw-r--r-- | tactics/rewrite.ml4 | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/tactics/rewrite.ml4 b/tactics/rewrite.ml4 index 334d653b12..f0ca4ae506 100644 --- a/tactics/rewrite.ml4 +++ b/tactics/rewrite.ml4 @@ -195,11 +195,17 @@ let proper_proof env evars carrier relation x = let goal = mkApp (Lazy.force proper_proxy_type, [| carrier ; relation; x |]) in new_cstr_evar evars env goal +let extends_undefined evars evars' = + let f ev evi found = found || not (Evd.mem evars ev) + in fold_undefined f evars' false + + let find_class_proof proof_type proof_method env evars carrier relation = try let goal = mkApp (Lazy.force proof_type, [| carrier ; relation |]) in - let evars, c = Typeclasses.resolve_one_typeclass env evars goal in - mkApp (Lazy.force proof_method, [| carrier; relation; c |]) + let evars', c = Typeclasses.resolve_one_typeclass env evars goal in + if extends_undefined evars evars' then raise Not_found + else mkApp (Lazy.force proof_method, [| carrier; relation; c |]) with e when Logic.catchable_exception e -> raise Not_found let get_reflexive_proof env = find_class_proof reflexive_type reflexive_proof env |