fix infix apply begin function issue

Author: EmileTrotignon

lib/Fmt_ast.ml

@@ -1875,7 +1875,8 @@ and fmt_infix_op_args c ~parens xexp op_args =
     in
     if Params.Exp.Infix_op_arg.dock c.conf xarg then
       (* Indentation of docked fun or function start before the operator. *)
-      hovbox 2 (fmt_expression c ~parens ~box:false ~pro xarg)
+      hovbox ~name:"Infix_op_arg docked" 2
+        (fmt_expression c ~parens ~box:false ~pro xarg)
     else
       match xarg.ast.pexp_desc with
       | Pexp_function _ | Pexp_beginend _ ->
@@ -2300,14 +2301,16 @@ and fmt_expression c ?(box = true) ?(pro = noop) ?eol ?parens
             else Break
           in
           let pro =
-            pro
+            intro_epi
             $ fmt_if parens (str "(")
             $ ( fmt_args_grouped ~epi:fmt_atrs e0 args_before
               $ fmt_if parens (closing_paren c ~force ~offset:(-3)) )
           in
           let label_sep = Params.Exp.fun_label_sep c.conf in
           let pro = pro $ break 1 0 $ fmt_label lbl label_sep in
-          hovbox 4 (fmt_expression c ~pro ~box:false (sub_exp ~ctx last_arg))
+          expr_epi
+          $ hovbox 4
+              (fmt_expression c ~pro ~box:false (sub_exp ~ctx last_arg))
       | _ ->
           let fmt_atrs =
             fmt_attributes c ~pre:(Break (1, -2)) pexp_attributes

lib/Params.ml

@@ -145,7 +145,11 @@ module Exp = struct
         | Pexp_apply (_, args) -> (
           (* Rhs is an apply and it ends with a [fun]. *)
           match List.last_exn args with
-          | _, {pexp_desc= Pexp_function _; _} -> true
+          | _, {pexp_desc= Pexp_function _; _}
+           |( _
+            , { pexp_desc= Pexp_beginend ({pexp_desc= Pexp_function _; _}, _)
+              ; _ } ) ->
+              true
           | _ -> false )
         | Pexp_match _ | Pexp_try _ -> true
         | _ -> false

test/passing/refs.janestreet/attributes.ml.ref

@@ -443,10 +443,10 @@ let () =
   let () =
     S.ntyp Cbor_type.Reserved
     @@ S.tok begin[@warning "-4"] fun ev ->
-           match ev with
-           | Cbor_event.Reserved int -> Some int
-           | _ -> None
-         end
+        match ev with
+        | Cbor_event.Reserved int -> Some int
+        | _ -> None
+      end
   in
   ()
 ;;

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

@@ -731,31 +731,25 @@ let _ =
 let () =
   fooooo
   |>>>>> List.iter begin fun a ->
-             let x =
-               some_really_really_really_long_name_that_doesn't_fit_on_the_line $ y
-             in
-             fooooooooooo x
-           end
+      let x = some_really_really_really_long_name_that_doesn't_fit_on_the_line $ y in
+      fooooooooooo x
+    end
 ;;
 
 let () =
   fooooo
   |>>>>> List.iter begin fun aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa ->
-             let x =
-               some_really_really_really_long_name_that_doesn't_fit_on_the_line $ y
-             in
-             fooooooooooo x
-           end
+      let x = some_really_really_really_long_name_that_doesn't_fit_on_the_line $ y in
+      fooooooooooo x
+    end
 ;;
 
 let () =
   fooooo
   |>>>>> List.iter begin fun a ->
-             let x =
-               some_really_really_really_long_name_that_doesn't_fit_on_the_line $ y
-             in
-             fooooooooooo x
-           end
+      let x = some_really_really_really_long_name_that_doesn't_fit_on_the_line $ y in
+      fooooooooooo x
+    end
 ;;
 
 let () =