Fix invalid widen call in topdown_term for side effects

Author: sim642

src/solver/sLR.ml

@@ -66,7 +66,7 @@ module SLR3 =
           if tracing then trace "sol" "Contrib:%a" S.Dom.pretty tmp;
           let tmp =
             if wpx then
-              if HM.mem globals x then S.Dom.widen old tmp
+              if HM.mem globals x then S.Dom.widen old tmp (* TODO: no join in second argument, can call widen incorrectly? *)
               else box old tmp
             else tmp
           in

src/solver/topDown_term.ml

@@ -85,7 +85,7 @@ module WP =
       and side y d =
         let old = try HM.find rho' y with Not_found -> S.Dom.bot () in
         if not (S.Dom.leq d old) then (
-          HM.replace rho' y (S.Dom.widen old d);
+          HM.replace rho' y (S.Dom.widen old (S.Dom.join old d));
           HM.remove stable y;
           init y;
           solve y Widen;