[@equal] annotation not working

[fangyi-zhou]

$ cat main.ml
type t
  = A of int * int [@equal fun (_, a) (_, b) -> Int.(a = b)]
  [@@deriving eq]

let a1 = A (1, 2)
let a2 = A (2, 2)
let () =
  Printf.printf "a1 and a2 are %s" (if equal a1 a2 then "equal" else "not equal")
$ ocamlfind ocamlopt -ppx '`ocamlfind query ppx_deriving`/ppx_deriving `ocamlfind query ppx_deriving`/eq/ppx_deriving_eq.cma' -dsource -c main.ml
type t =
  | A of int * int [@equal fun (_, a) -> fun (_, b) -> let open Int in a = b]
[@@deriving eq]
let rec (equal : t -> t -> Ppx_deriving_runtime.bool) =
  ((let open! ((Ppx_deriving_runtime)[@ocaml.warning "-A"]) in
      fun lhs ->
        fun rhs ->
          match (lhs, rhs) with
          | (A (lhs0, lhs1), A (rhs0, rhs1)) ->
              ((fun (a : int) -> fun b -> a = b) lhs0 rhs0) &&
                (((fun (a : int) -> fun b -> a = b)) lhs1 rhs1)
          | _ -> false)
  [@ocaml.warning "-A"])[@@ocaml.warning "-39"]
let a1 = A (1, 2)
let a2 = A (2, 2)
let () =
  Printf.printf "a1 and a2 are %s"
    (if equal a1 a2 then "equal" else "not equal")
File "main.ml", line 1, characters 0-85:
1 | type t
2 |   = A of int * int [@equal fun (_, a) (_, b) -> Int.(a = b)]
3 |   [@@deriving eq]
Error: Unbound module Ppx_deriving_runtime

I think the [@Equal] annotation is not taken care of inside the variant.

(I also find it difficult to debug the situation - I ran into the issue #150 when trying to get the AST)

[fangyi-zhou]

I figured out this is similar to #209, but I was expecting this to work

type t
   = A of int * int [@equal fun (_, a) (_, b) -> Int.(a = b)]
   | B of string
   [@@deriving eq]