[proof] optimize proof always works on incomplete proofs

1 files changed, 1 insertions, 1 deletions

diff --git a/engine/proofview.ml b/engine/proofview.ml
index cf4224bbdb..d4ad53ff5f 100644
--- a/engine/proofview.ml
+++ b/engine/proofview.ml
@@ -39,7 +39,7 @@ let proofview p =
 
 let compact el ({ solution } as pv) =
   let nf c = Evarutil.nf_evar solution c in
-  let nf0 c = EConstr.(to_constr solution (of_constr c)) in
+  let nf0 c = EConstr.(to_constr ~abort_on_undefined_evars:false solution (of_constr c)) in
   let size = Evd.fold (fun _ _ i -> i+1) solution 0 in
   let new_el = List.map (fun (t,ty) -> nf t, nf ty) el in
   let pruned_solution = Evd.drop_all_defined solution in