wip: use Lit.Set.t for explanations

src/smt/Congruence_closure.ml

@@ -28,7 +28,7 @@ type actions = {
   raise_conflict: 'a. Lit.Set.t -> 'a;
   (** Report a conflict *)
 
-  propagate: Lit.t -> Explanation.t Bag.t -> unit;
+  propagate: Lit.t -> Lit.t list -> unit;
   (** Propagate a literal *)
 }
 

src/smt/Congruence_closure.mli

@@ -21,8 +21,7 @@ type actions = {
   raise_conflict: 'a. Lit.Set.t -> 'a;
   (** Report a conflict *)
 
-  (* FIXME: take a delayed Lit.Set.t? *)
+  propagate: Lit.t -> Lit.t list -> unit;
-  propagate: Lit.t -> Explanation.t Bag.t -> unit;
   (** Propagate a literal *)
 }
 

src/smt/Theory.ml

@@ -41,13 +41,13 @@ type actions = {
   raise_conflict: 'a. conflict -> 'a;
   (** Give a conflict clause to the solver *)
 
-  propagate_eq: Term.t -> Term.t -> Explanation.t -> unit;
+  propagate_eq: Term.t -> Term.t -> Lit.Set.t -> unit;
   (** Propagate an equality [t = u] because [e] *)
 
-  propagate_distinct: Term.t list -> neq:Term.t -> Explanation.t -> unit;
+  propagate_distinct: Term.t list -> neq:Term.t -> Lit.t -> unit;
-  (** Propagate a [distinct l] because [e] (where [e = atom neq] *)
+  (** Propagate a [distinct l] because [e] (where [e = neq] *)
 
-  propagate: Lit.t -> Explanation.t Bag.t -> unit;
+  propagate: Lit.t -> Lit.Set.t -> unit;
   (** Propagate a boolean using a unit clause.
       [expl => lit] must be a theory lemma, that is, a T-tautology *)
 

src/smt/Theory_combine.ml

@@ -126,10 +126,6 @@ let if_sat (self:t) (slice:_) : _ Sat_solver.res =
 (* forward propagations from CC or theories directly to the SMT core *)
 let act_propagate (self:t) f guard : unit =
   let Sat_solver.Actions r = self.cdcl_acts in
-  let guard =
-    Congruence_closure.explain_unfold_bag (cc self) guard
-    |> Lit.Set.to_list
-  in
   Sat_solver.Log.debugf 2
     (fun k->k "(@[@{<green>propagate@}@ %a@ :guard %a@])"
         Lit.pp f (Util.pp_list Lit.pp) guard);

src/smt/th_bool/Sidekick_th_bool.ml

@@ -255,13 +255,13 @@ let tseitin (self:t) (lit:Lit.t) (lit_t:term) (b:term builtin) : unit =
   | B_not _ -> assert false (* normalized *)
   | B_eq (t,u) ->
     if Lit.sign lit then (
-      self.acts.Theory.propagate_eq t u (Explanation.lit lit)
+      self.acts.Theory.propagate_eq t u (Lit.Set.singleton lit)
     ) else (
-      self.acts.Theory.propagate_distinct [t;u] ~neq:lit_t (Explanation.lit lit)
+      self.acts.Theory.propagate_distinct [t;u] ~neq:lit_t lit
     )
   | B_distinct l ->
     if Lit.sign lit then (
-      self.acts.Theory.propagate_distinct l ~neq:lit_t (Explanation.lit lit)
+      self.acts.Theory.propagate_distinct l ~neq:lit_t lit
     ) else (
       (* TODO: propagate pairwise equalities? *)
       Error.errorf "cannot process negative distinct lit %a" Lit.pp lit;
@@ -269,7 +269,7 @@ let tseitin (self:t) (lit:Lit.t) (lit_t:term) (b:term builtin) : unit =
   | B_and subs ->
     if Lit.sign lit then (
       (* propagate [lit => subs_i] *)
-      let expl = Bag.return (Explanation.lit lit) in
+      let expl = Lit.Set.singleton lit in
       List.iter
         (fun sub ->
            let sublit = Lit.atom sub in
@@ -277,7 +277,7 @@ let tseitin (self:t) (lit:Lit.t) (lit_t:term) (b:term builtin) : unit =
         subs
     ) else (
       (* propagate [¬lit => ∨_i ¬ subs_i] *)
-      let c = lit :: List.map (Lit.atom ~sign:false) subs in
+      let c = Lit.neg lit :: List.map (Lit.atom ~sign:false) subs in
       self.acts.Theory.add_local_axiom (IArray.of_list c)
     )
   | B_or subs ->
@@ -287,7 +287,7 @@ let tseitin (self:t) (lit:Lit.t) (lit_t:term) (b:term builtin) : unit =
       self.acts.Theory.add_local_axiom (IArray.of_list c)
     ) else (
       (* propagate [¬lit => ¬subs_i] *)
-      let expl = Bag.return (Explanation.lit lit) in
+      let expl = Lit.Set.singleton lit in
       List.iter
         (fun sub ->
            let sublit = Lit.atom ~sign:false sub in
@@ -300,7 +300,7 @@ let tseitin (self:t) (lit:Lit.t) (lit_t:term) (b:term builtin) : unit =
       let c = Lit.atom concl :: Lit.neg lit :: List.map (Lit.atom ~sign:false) guard in
       self.acts.Theory.add_local_axiom (IArray.of_list c)
     ) else (
-      let expl = Bag.return (Explanation.lit lit) in
+      let expl = Lit.Set.singleton lit in
       (* propagate [¬lit => ¬concl] *)
       self.acts.Theory.propagate (Lit.atom ~sign:false concl) expl;
       (* propagate [¬lit => ∧_i guard_i] *)