diff options
Diffstat (limited to 'toplevel')
| -rw-r--r-- | toplevel/command.ml | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/toplevel/command.ml b/toplevel/command.ml index 51af38e20..ab2517b28 100644 --- a/toplevel/command.ml +++ b/toplevel/command.ml @@ -418,7 +418,11 @@ let start_proof_com sopt stre com = let env = Global.env () in let sign = Global.named_context () in let id = match sopt with - | Some id -> id + | Some id -> + (* We check existence here: it's a bit late at Qed time *) + if Nametab.exists_cci (Lib.make_path id CCI) then + errorlabstrm "start_proof" [< pr_id id; 'sTR " already exists" >]; + id | None -> next_ident_away (id_of_string "Unnamed_thm") (Pfedit.get_all_proof_names ()) |