Merge branch 'v8.5' into v8.6

9 files changed, 109 insertions, 5 deletions

diff --git a/engine/ftactic.ml b/engine/ftactic.ml
index 588709873..aeaaea7e4 100644
--- a/engine/ftactic.ml
+++ b/engine/ftactic.ml
@@ -29,13 +29,28 @@ let bind (type a) (type b) (m : a t) (f : a -> b t) : b t = m >>= function
   | Uniform x ->
     (** We dispatch the uniform result on each goal under focus, as we know
         that the [m] argument was actually dependent. *)
-    Proofview.Goal.goals >>= fun l ->
-    let ans = List.map (fun _ -> x) l in
+    Proofview.Goal.goals >>= fun goals ->
+    let ans = List.map (fun g -> (g,x)) goals in
     Proofview.tclUNIT ans
-  | Depends l -> Proofview.tclUNIT l
+  | Depends l ->
+    Proofview.Goal.goals >>= fun goals ->
+    Proofview.tclUNIT (List.combine goals l)
+  in
+  (* After the tactic has run, some goals which were previously
+     produced may have been solved by side effects. The values
+     attached to such goals must be discarded, otherwise the list of
+     result would not have the same length as the list of focused
+     goals, which is an invariant of the [Ftactic] module. It is the
+     reason why a goal is attached to each result above. *)
+  let filter (g,x) =
+    g >>= fun g ->
+    Proofview.Goal.unsolved g >>= function
+    | true -> Proofview.tclUNIT (Some x)
+    | false -> Proofview.tclUNIT None
   in
   Proofview.tclDISPATCHL (List.map f l) >>= fun l ->
-  Proofview.tclUNIT (Depends (List.concat l))
+  Proofview.Monad.List.map_filter filter (List.concat l) >>= fun filtered ->
+  Proofview.tclUNIT (Depends filtered)
 
 let goals = Proofview.Goal.goals >>= fun l -> Proofview.tclUNIT (Depends l)
 let set_sigma r =
diff --git a/engine/proofview.ml b/engine/proofview.ml
index a2838a2de..f2f400515 100644
--- a/engine/proofview.ml
+++ b/engine/proofview.ml
@@ -929,6 +929,8 @@ module Unsafe = struct
       { step with comb = step.comb @ gls }
     end
 
+  let tclSETENV = Env.set
+
   let tclGETGOALS = Comb.get
 
   let tclSETGOALS = Comb.set
@@ -1129,6 +1131,10 @@ module Goal = struct
     in
     tclUNIT (CList.map_filter map step.comb)
 
+  let unsolved { self=self } =
+    tclEVARMAP >>= fun sigma ->
+    tclUNIT (not (Option.is_empty (advance sigma self)))
+
   (* compatibility *)
   let goal { self=self } = self
 
diff --git a/engine/proofview.mli b/engine/proofview.mli
index bc68f11ff..fae75f825 100644
--- a/engine/proofview.mli
+++ b/engine/proofview.mli
@@ -409,6 +409,9 @@ module Unsafe : sig
   (** Like {!tclEVARS} but also checks whether goals have been solved. *)
   val tclEVARSADVANCE : Evd.evar_map -> unit tactic
 
+  (** Set the global environment of the tactic *)
+  val tclSETENV : Environ.env -> unit tactic
+
   (** [tclNEWGOALS gls] adds the goals [gls] to the ones currently
       being proved, appending them to the list of focused goals. If a
       goal is already solved, it is not added. *)
@@ -518,6 +521,10 @@ module Goal : sig
       FIXME: encapsulate the level in an existential type. *)
   val goals : ([ `LZ ], 'r) t tactic list tactic
 
+  (** [unsolved g] is [true] if [g] is still unsolved in the current
+      proof state. *)
+  val unsolved : ('a, 'r) t -> bool tactic
+
   (** Compatibility: avoid if possible *)
   val goal : ([ `NF ], 'r) t -> Evar.t
 
diff --git a/kernel/entries.mli b/kernel/entries.mli
index df2c4653f..ea7c266bc 100644
--- a/kernel/entries.mli
+++ b/kernel/entries.mli
@@ -98,7 +98,12 @@ type module_entry =
   | MExpr of
       module_params_entry * module_struct_entry * module_struct_entry option
 
-type seff_env = [ `Nothing | `Opaque of Constr.t * Univ.universe_context_set ]
+
+type seff_env =
+  [ `Nothing
+  (* The proof term and its universes.
+     Same as the constant_body's but not in an ephemeron *)
+  | `Opaque of Constr.t * Univ.universe_context_set ]
 
 type side_eff =
   | SEsubproof of constant * Declarations.constant_body * seff_env
diff --git a/lib/monad.ml b/lib/monad.ml
index a1714a41b..2e55e9698 100644
--- a/lib/monad.ml
+++ b/lib/monad.ml
@@ -64,6 +64,9 @@ module type ListS = sig
       its second argument in a tail position. *)
   val iter : ('a -> unit t) -> 'a list -> unit t
 
+  (** Like the regular {!CList.map_filter}. The monadic effects are threaded left*)
+  val map_filter : ('a -> 'b option t) -> 'a list -> 'b list t
+
 
   (** {6 Two-list iterators} *)
 
@@ -138,6 +141,14 @@ module Make (M:Def) : S with type +'a t = 'a M.t = struct
       | a::b::l -> f a >> f b >> iter f l
 
 
+    let rec map_filter f = function
+      | [] -> return []
+      | a::l ->
+        f a >>= function
+        | None -> map_filter f l
+        | Some b ->
+          map_filter f l >>= fun filtered ->
+          return (b::filtered)
 
     let rec fold_left2 r f x l1 l2 =
       match l1,l2 with
diff --git a/lib/monad.mli b/lib/monad.mli
index c8655efa0..f7de71f53 100644
--- a/lib/monad.mli
+++ b/lib/monad.mli
@@ -66,6 +66,9 @@ module type ListS = sig
       its second argument in a tail position. *)
   val iter : ('a -> unit t) -> 'a list -> unit t
 
+  (** Like the regular {!CList.map_filter}. The monadic effects are threaded left*)
+  val map_filter : ('a -> 'b option t) -> 'a list -> 'b list t
+
 
   (** {6 Two-list iterators} *)
 
diff --git a/proofs/refine.ml b/proofs/refine.ml
index dc6f4cea1..e5114a2ec 100644
--- a/proofs/refine.ml
+++ b/proofs/refine.ml
@@ -51,6 +51,23 @@ let typecheck_proof c concl env sigma =
 let (pr_constrv,pr_constr) =
   Hook.make ~default:(fun _env _sigma _c -> Pp.str"<constr>") ()
 
+(* Get the side-effect's constant declarations to update the monad's
+  * environmnent *)
+let add_if_undefined kn cb env =
+  try ignore(Environ.lookup_constant kn env); env
+  with Not_found -> Environ.add_constant kn cb env
+
+(* Add the side effects to the monad's environment, if not already done. *)
+let add_side_effect env = function
+  | { Entries.eff = Entries.SEsubproof (kn, cb, eff_env) } ->
+    add_if_undefined kn cb env
+  | { Entries.eff = Entries.SEscheme (l,_) } ->
+    List.fold_left (fun env (_,kn,cb,eff_env) ->
+        add_if_undefined kn cb env) env l
+
+let add_side_effects env effects =
+  List.fold_left (fun env eff -> add_side_effect env eff) env effects
+
 let make_refine_enter ?(unsafe = true) f =
   { enter = fun gl ->
   let gl = Proofview.Goal.assume gl in
@@ -66,6 +83,10 @@ let make_refine_enter ?(unsafe = true) f =
   let ((v,c), sigma) = Sigma.run (Evd.reset_future_goals sigma) f in
   let evs = Evd.future_goals sigma in
   let evkmain = Evd.principal_future_goal sigma in
+  (** Redo the effects in sigma in the monad's env *)
+  let privates_csts = Evd.eval_side_effects sigma in
+  let sideff = Safe_typing.side_effects_of_private_constants privates_csts in
+  let env = add_side_effects env sideff in
   (** Check that the introduced evars are well-typed *)
   let fold accu ev = typecheck_evar ev env accu in
   let sigma = if unsafe then sigma else CList.fold_left fold sigma evs in
@@ -94,6 +115,7 @@ let make_refine_enter ?(unsafe = true) f =
   let sigma = CList.fold_left Proofview.Unsafe.mark_as_goal sigma comb in
   let trace () = Pp.(hov 2 (str"simple refine"++spc()++ Hook.get pr_constrv env sigma c)) in
   Proofview.Trace.name_tactic trace (Proofview.tclUNIT v) >>= fun v ->
+  Proofview.Unsafe.tclSETENV (Environ.reset_context env) <*>
   Proofview.Unsafe.tclEVARS sigma <*>
   Proofview.Unsafe.tclSETGOALS comb <*>
   Proofview.tclUNIT v
diff --git a/test-suite/bugs/closed/4416.v b/test-suite/bugs/closed/4416.v
new file mode 100644
index 000000000..b97a8ce64
--- /dev/null
+++ b/test-suite/bugs/closed/4416.v
@@ -0,0 +1,3 @@
+Goal exists x, x.
+unshelve refine (ex_intro _ _ _); match goal with _ => refine (_ _) end.
+(* Error: Incorrect number of goals (expected 2 tactics). *)
\ No newline at end of file
diff --git a/test-suite/bugs/closed/4863.v b/test-suite/bugs/closed/4863.v
new file mode 100644
index 000000000..e884355fd
--- /dev/null
+++ b/test-suite/bugs/closed/4863.v
@@ -0,0 +1,32 @@
+Require Import Classes.DecidableClass.
+
+Inductive Foo : Set :=
+| foo1 | foo2.
+
+Instance Decidable_sumbool : forall P, {P}+{~P} -> Decidable P.
+Proof.
+  intros P H.
+  refine (Build_Decidable _ (if H then true else false) _).
+  intuition congruence.
+Qed.
+
+Hint Extern 100 ({?A = ?B}+{~ ?A = ?B}) => abstract (abstract (abstract (decide equality))) : typeclass_instances.
+
+Goal forall (a b : Foo), {a=b}+{a<>b}.
+intros.
+abstract (abstract (decide equality)). (*abstract works here*)
+Qed.
+
+Check ltac:(abstract (exact I)) : True.
+
+Goal forall (a b : Foo), Decidable (a=b) * Decidable (a=b).
+intros.
+split. typeclasses eauto. typeclasses eauto. Qed.
+
+Goal forall (a b : Foo), Decidable (a=b) * Decidable (a=b).
+intros.
+split.
+refine _.
+refine _.
+Defined.
+(*fails*)