OCaml 5.4 support #1057
Description
Using OCaml 5.4 (and the upcoming ppxlib 0.37.0~5.4preview), lwt_ppx fails to build with:
#=== ERROR while compiling lwt_ppx.5.9.1 ======================================#
# context 2.4.0~alpha2 | linux/x86_64 | ocaml-base-compiler.5.4.0~alpha1 | https://opam.ocaml.org#584630e7a7e27e3cf56158696a3fe94623a0cf4f
# path ~/.opam/default/.opam-switch/build/lwt_ppx.5.9.1
# command ~/.opam/opam-init/hooks/sandbox.sh build dune build -p lwt_ppx -j 31 @install
# exit-code 1
# env-file ~/.opam/log/lwt_ppx-20663-567f81.env
# output-file ~/.opam/log/lwt_ppx-20663-567f81.out
### output ###
# Error: The value cases has type Ppxlib.case list
# [...]
# (cd _build/default && /home/opam-health-check/.opam/default/bin/ocamlc.opt -w -40 -w +A-4 -g -bin-annot -bin-annot-occurrences -I src/ppx/.ppx_lwt.objs/byte -I /home/opam-health-check/.opam/default/lib/ocaml-compi
ler-libs/common -I /home/opam-health-check/.opam/default/lib/ocaml-compiler-libs/shadow -I /home/opam-health-check/.opam/default/lib/ocaml/compiler-libs -I /home/opam-health-check/.o[...]
# File "src/ppx/ppx_lwt.ml", line 147, characters 54-59:
# 147 | [%expr Lwt.bind [%e e] [%e pexp_function ~loc cases]]
# ^^^^^
# Error: The value cases has type Ppxlib.case list
# but an expression was expected of type
# Ppxlib__.Import.function_param list
# Type Ppxlib.case = Astlib.Ast_502.Parsetree.case
# is not compatible with type
# Ppxlib__.Import.function_param =
# Astlib.Ast_502.Parsetree.function_param