diff options
Diffstat (limited to 'pretyping/typeclasses.ml')
| -rw-r--r-- | pretyping/typeclasses.ml | 32 |
1 files changed, 22 insertions, 10 deletions
diff --git a/pretyping/typeclasses.ml b/pretyping/typeclasses.ml index 18c9650bd1..d732544c5c 100644 --- a/pretyping/typeclasses.ml +++ b/pretyping/typeclasses.ml @@ -427,28 +427,40 @@ let remove_instance i = Lib.add_anonymous_leaf (instance_input (RemoveInstance, i)); remove_instance_hint i.is_impl -let declare_instance info local glob = +let warning_not_a_class = + let name = "not-a-class" in + let category = "typeclasses" in + CWarnings.create ~name ~category (fun (n, ty) -> + let env = Global.env () in + let evd = Evd.from_env env in + Pp.(str "Ignored instance declaration for “" + ++ Nametab.pr_global_env Id.Set.empty n + ++ str "”: “" + ++ Termops.Internal.print_constr_env env evd (EConstr.of_constr ty) + ++ str "” is not a class") + ) + +let declare_instance ?(warn = false) info local glob = let ty, _ = Typeops.type_of_global_in_context (Global.env ()) glob in let info = Option.default {hint_priority = None; hint_pattern = None} info in match class_of_constr Evd.empty (EConstr.of_constr ty) with | Some (rels, ((tc,_), args) as _cl) -> assert (not (isVarRef glob) || local); add_instance (new_instance tc info (not local) glob) - | None -> () + | None -> if warn then warning_not_a_class (glob, ty) let add_class cl = add_class cl; List.iter (fun (n, inst, body) -> - match inst with - | Some (Backward, info) -> - (match body with - | None -> CErrors.user_err Pp.(str "Non-definable projection can not be declared as a subinstance") - | Some b -> declare_instance (Some info) false (ConstRef b)) - | _ -> ()) - cl.cl_projs + match inst with + | Some (Backward, info) -> + (match body with + | None -> CErrors.user_err Pp.(str "Non-definable projection can not be declared as a subinstance") + | Some b -> declare_instance ~warn:true (Some info) false (ConstRef b)) + | _ -> ()) + cl.cl_projs - (* * interface functions *) |