fix one branch try

Author: EmileTrotignon

lib/Fmt_ast.ml

@@ -2564,18 +2564,22 @@ and fmt_expression c ?(box = true) ?(pro = noop) ?eol ?parens
            && c.conf.fmt_opts.break_cases.v <> `All
            && c.conf.fmt_opts.break_cases.v <> `Vertical ) ->
       let cmts_before = Cmts.fmt_before c ?eol pexp_loc in
+      let pro_outer, pro_inner =
+        if Params.Exp.box_pro_with_match ~ctx0 ~parens then (noop, pro)
+        else (pro, noop)
+      in
       (* side effects of Cmts.fmt_before before [fmt_pattern] is important *)
       let xpc_rhs = sub_exp ~ctx pc_rhs in
       let leading_cmt = Cmts.fmt_before c pc_lhs.ppat_loc in
       let parens_here, parens_for_exp =
         if c.conf.fmt_opts.leading_nested_match_parens.v then (false, None)
         else (parenze_exp xpc_rhs, Some false)
       in
-      cmts_before $ pro
+      cmts_before $ pro_outer
       $ Params.Exp.wrap c.conf ~parens ~disambiguate:true
           (hvbox 2
              ( hvbox 0
-                 ( str "try"
+                 ( hvbox 0 (pro_inner $ str "try")
                  $ fmt_extension_suffix c ext
                  $ fmt_attributes c pexp_attributes
                  $ break 1 2

test/passing/refs.default/exp_grouping-parens.ml.ref

@@ -319,9 +319,7 @@ let x =
       match Tbl.find dist_tbl (pv1, pv2) with
       | None ->
           (* FIXME: temporary hack to avoid Jane Street's annoying warnings. *)
-          begin
-          [@warning "-3"]
-          try
+          begin [@warning "-3"] try
             let path', dist = Dijkstra.shortest_path pgraph pv1 pv2 in
             let path = unwrap_path path' in
             Tbl.set dist_tbl ~key:(pv1, pv2) ~data:(path, dist);

test/passing/refs.default/exp_grouping.ml.ref

@@ -375,9 +375,7 @@ let x =
       match Tbl.find dist_tbl (pv1, pv2) with
       | None ->
           (* FIXME: temporary hack to avoid Jane Street's annoying warnings. *)
-          begin
-          [@warning "-3"]
-          try
+          begin [@warning "-3"] try
             let path', dist = Dijkstra.shortest_path pgraph pv1 pv2 in
             let path = unwrap_path path' in
             Tbl.set dist_tbl ~key:(pv1, pv2) ~data:(path, dist);

test/passing/refs.ocamlformat/exp_grouping-parens.ml.ref

@@ -319,9 +319,7 @@ let x =
       match Tbl.find dist_tbl (pv1, pv2) with
       | None ->
         (* FIXME: temporary hack to avoid Jane Street's annoying warnings. *)
-        begin
-        [@warning "-3"]
-        try
+        begin [@warning "-3"] try
           let path', dist = Dijkstra.shortest_path pgraph pv1 pv2 in
           let path = unwrap_path path' in
           Tbl.set dist_tbl ~key:(pv1, pv2) ~data:(path, dist) ;

test/passing/refs.ocamlformat/exp_grouping.ml.ref

@@ -375,9 +375,7 @@ let x =
       match Tbl.find dist_tbl (pv1, pv2) with
       | None ->
         (* FIXME: temporary hack to avoid Jane Street's annoying warnings. *)
-        begin
-        [@warning "-3"]
-        try
+        begin [@warning "-3"] try
           let path', dist = Dijkstra.shortest_path pgraph pv1 pv2 in
           let path = unwrap_path path' in
           Tbl.set dist_tbl ~key:(pv1, pv2) ~data:(path, dist) ;