refactor: remove a bunch of useless "let open Memo.O in"

src/dune_rules/artifact_substitution.ml

@@ -1,4 +1,5 @@
 open Import
+open Memo.O
 
 (* Artifact substitutions works as follow: the substitution is encoded as a
    string of the form:
@@ -94,7 +95,6 @@ module Conf = struct
   ;;
 
   let sign_hook_of_context (context : Context.t) =
-    let open Memo.O in
     let+ config =
       let+ ocaml = Context.ocaml context in
       ocaml.ocaml_config
@@ -116,7 +116,6 @@ module Conf = struct
   ;;
 
   let of_context (context : Context.t) =
-    let open Memo.O in
     let get_vcs = Source_tree.nearest_vcs in
     let name = Context.name context in
     let get_location = Install.Paths.get_local_location name in
@@ -139,7 +138,6 @@ module Conf = struct
   ;;
 
   let of_install ~relocatable ~roots ~(context : Context.t) =
-    let open Memo.O in
     let get_vcs = Source_tree.nearest_vcs in
     let hardcoded_ocaml_path =
       match relocatable with
@@ -194,7 +192,6 @@ let eval t ~(conf : Conf.t) =
   let relocatable path =
     (* return a relative path to the install directory in case of relocatable
        instead of absolute path *)
-    let open Memo.O in
     conf.hardcoded_ocaml_path
     >>| function
     | Hardcoded _ -> Path.to_absolute_filename path
@@ -205,8 +202,7 @@ let eval t ~(conf : Conf.t) =
     Fiber.return (Array.make n s |> Array.to_list |> String.concat ~sep:"")
   | Vcs_describe p ->
     Memo.run
-      (let open Memo.O in
-       conf.get_vcs p
+      (conf.get_vcs p
        >>= function
        | None -> Memo.return ""
        | Some vcs ->
@@ -215,21 +211,19 @@ let eval t ~(conf : Conf.t) =
   | Location (name, lib_name) ->
     conf.get_location name lib_name |> relocatable |> Memo.run
   | Configpath d ->
-    let open Memo.O in
     (let* dir = conf.get_config_path d in
      match dir with
      | None -> Memo.return None
      | Some dir -> relocatable dir >>| Option.some)
     >>| Option.value ~default:""
     |> Memo.run
   | Hardcoded_ocaml_path ->
-    (let open Memo.O in
-     conf.hardcoded_ocaml_path
-     >>| function
-     | Relocatable _ -> "relocatable"
-     | Hardcoded l ->
-       let l = List.map l ~f:Path.to_absolute_filename in
-       "hardcoded\000" ^ String.concat ~sep:"\000" l)
+    conf.hardcoded_ocaml_path
+    >>| (function
+           | Relocatable _ -> "relocatable"
+           | Hardcoded l ->
+             let l = List.map l ~f:Path.to_absolute_filename in
+             "hardcoded\000" ^ String.concat ~sep:"\000" l)
     |> Memo.run
 ;;
 

src/dune_rules/artifacts_db.ml

@@ -28,14 +28,12 @@ let available_exes ~dir (exes : Executables.t) =
       ~forbidden_libraries:exes.forbidden_libraries
       ~allow_overlaps:exes.buildable.allow_overlapping_dependencies
   in
-  let open Memo.O in
   let+ available = Lib.Compile.direct_requires compile_info in
   Resolve.is_ok available
 ;;
 
 let get_installed_binaries ~(context : Context.t) stanzas =
   let merge _ x y = Some (Appendable_list.( @ ) x y) in
-  let open Memo.O in
   Memo.List.map stanzas ~f:(fun d ->
     let dir = Path.Build.append_source (Context.build_dir context) (Dune_file.dir d) in
     let* expander = Expander0.get ~dir in

src/dune_rules/blang_expand.ml

@@ -1,7 +1,7 @@
 open Import
+open Memo.O
 
 let rec eval (t : Blang.t) ~dir ~f =
-  let open Memo.O in
   match t with
   | Const x -> Memo.return x
   | Expr sw ->

src/dune_rules/buildable_rules.ml

@@ -22,7 +22,6 @@ let ocaml_flags t ~dir (spec : Ocaml_flags.Spec.t) =
 ;;
 
 let gen_select_rules sctx ~dir compile_info =
-  let open Memo.O in
   Lib.Compile.resolved_selects compile_info
   |> Resolve.Memo.read_memo
   >>= Memo.parallel_iter ~f:(fun { Lib.Compile.Resolved_select.dst_fn; src_fn } ->

src/dune_rules/cinaps.ml

@@ -1,4 +1,5 @@
 open Import
+open Memo.O
 
 type t =
   { loc : Loc.t
@@ -75,7 +76,6 @@ let () =
 ;;
 
 let gen_rules sctx t ~dir ~scope =
-  let open Memo.O in
   let loc = t.loc in
   (* Files checked by cinaps *)
   let* cinapsed_files =

src/dune_rules/compilation_context.ml

@@ -1,4 +1,5 @@
 open Import
+open Memo.O
 
 module Includes = struct
   type t = Command.Args.without_targets Command.Args.t Lib_mode.Cm_kind.Map.t
@@ -145,7 +146,6 @@ let create
   ?loc
   ()
   =
-  let open Memo.O in
   let project = Scope.project scope in
   let context = Super_context.context super_context in
   let* ocaml = Context.ocaml context in
@@ -325,7 +325,6 @@ let entry_module_names sctx t =
   match Lib_info.entry_modules (Lib.info t) with
   | External d -> Resolve.Memo.of_result d
   | Local ->
-    let open Memo.O in
     let+ modules = Dir_contents.modules_of_lib sctx t in
     let modules = Option.value_exn modules in
     Resolve.return (Modules.With_vlib.entry_modules modules |> List.map ~f:Module.name)

src/dune_rules/cond_expand.ml

@@ -1,8 +1,7 @@
-open! Stdune
 open! Import
+open Memo.O
 
 let eval (cond : Dune_lang.Cond.t) ~dir ~f =
-  let open Memo.O in
   let expand_sw = String_expander.Memo.expand ~mode:Single ~dir ~f in
   let* from_case =
     Memo.List.find_map cond.cases ~f:(fun (blang, sw) ->

src/dune_rules/cram/cram_rules.ml

@@ -126,7 +126,6 @@ let collect_stanzas =
 ;;
 
 let rules ~sctx ~dir tests =
-  let open Memo.O in
   let* stanzas = collect_stanzas ~dir
   and* with_package_mask =
     Dune_load.mask ()

src/dune_rules/ctypes/ctypes_rules.ml

@@ -1,4 +1,5 @@
 open Import
+open Memo.O
 
 (* This module expands either a (library ... (ctypes ...)) rule or an
    (executables ... (ctypes ...)) rule into the generated set of .ml and .c
@@ -295,7 +296,6 @@ let gen_rules ~cctx ~(buildable : Buildable.t) ~loc ~scope ~dir ~sctx =
   let type_description_functor = ctypes.type_description.functor_ in
   let c_types_includer_module = ctypes.generated_types in
   let c_generated_types_module = Ctypes_field.c_generated_types_module ctypes in
-  let open Memo.O in
   let foreign_archives_deps =
     let { Lib_config.ext_lib; ext_dll; _ } =
       (Compilation_context.ocaml cctx).lib_config
@@ -331,7 +331,6 @@ let gen_rules ~cctx ~(buildable : Buildable.t) ~loc ~scope ~dir ~sctx =
       |> Memo.return
     | Pkg_config ->
       let+ () =
-        let open Memo.O in
         let setup query =
           let* res = Pkg_config.gen_rule sctx ~dir ~loc query in
           match res with

src/dune_rules/dep_rules.ml

@@ -83,7 +83,6 @@ let deps_of_vlib_module ({ obj_dir; vimpl; dir; sctx; _ } as md) ~ml_kind source
       let impl = Vimpl.impl vimpl in
       Dune_project.dune_version impl.project
     in
-    let open Memo.O in
     let+ deps = ooi_deps md ~dune_version ~vlib_obj_map ~ml_kind sourced_module in
     Action_builder.map deps ~f:(List.map ~f:Modules.Sourced_module.to_module)
   | Some lib ->

src/dune_rules/dune_file.ml

@@ -1,4 +1,5 @@
 open Import
+open Memo.O
 
 type t =
   { dir : Path.Source.t
@@ -91,7 +92,6 @@ let rec parse_file_includes ~stanza_parser ~context sexps =
   |> Memo.List.concat_map ~f:(fun stanza ->
     match Stanza.repr stanza with
     | Stanzas.Include.T (loc, fn) ->
-      let open Memo.O in
       let* sexps, context = Include_stanza.load_sexps ~context (loc, fn) in
       parse_file_includes ~stanza_parser ~context sexps
     | _ -> Memo.return [ stanza ])
@@ -105,7 +105,6 @@ type eval =
 
 let parse_stanzas ~file ~(eval : eval) sexps =
   let warnings = Warning_emit.Bag.create () in
-  let open Memo.O in
   let* stanzas =
     let context =
       Include_stanza.in_src_file
@@ -146,7 +145,6 @@ let parse_stanzas ~file ~(eval : eval) sexps =
 ;;
 
 let parse sexps ~file ~(eval : eval) =
-  let open Memo.O in
   let+ stanzas, dynamic_includes = parse_stanzas sexps ~file ~eval in
   ( { dir = eval.dir
     ; project = eval.project
@@ -180,7 +178,6 @@ let fold_static_stanzas t ~init ~f = Id_fold.fold_static_stanzas t ~init ~f
 let to_dyn = Dyn.opaque
 
 let find_stanzas t key =
-  let open Memo.O in
   let+ stanzas = Memo.Lazy.force t.stanzas in
   (* CR-rgrinberg: save a map to represent the stanzas to make this fast. *)
   List.filter_map stanzas ~f:(Stanza.Key.get key)
@@ -293,7 +290,6 @@ end = struct
   ;;
 
   let create_plugin_wrapper context ocaml_config ~exec_dir ~plugin ~wrapper ~target =
-    let open Memo.O in
     let+ plugin_contents = Fs_memo.file_contents plugin in
     Io.with_file_out (Path.build wrapper) ~f:(fun oc ->
       write oc ~context ~ocaml_config ~target ~exec_dir ~plugin ~plugin_contents);

src/dune_rules/dune_load.ml

@@ -42,7 +42,6 @@ module Source_tree_map_reduce =
   Source_tree.Make_map_reduce_with_progress (Memo) (Projects_and_dune_files)
 
 let load () =
-  let open Memo.O in
   let status dir =
     match Source_tree.Dir.status dir with
     | Vendored -> `Vendored

src/dune_rules/env_binaries.ml

@@ -5,7 +5,6 @@ let expand_str_lazy expander sw =
   match String_with_vars.text_only sw with
   | Some s -> Memo.return s
   | None ->
-    let open Memo.O in
     let* expander = Memo.Lazy.force expander in
     Expander.No_deps.expand_str expander sw
 ;;

src/dune_rules/env_stanza_db.ml

@@ -8,7 +8,6 @@ module Node = struct
     }
 
   let by_context dir =
-    let open Memo.O in
     let+ context = Context.DB.by_dir dir in
     let { Context.Env_nodes.context; workspace } = Context.env_nodes context in
     match context, workspace with

src/dune_rules/exe.ml

@@ -1,4 +1,5 @@
 open Import
+open Memo.O
 
 module Program = struct
   type t =
@@ -153,7 +154,6 @@ let link_exe
   let exe = exe_path_from_name cctx ~name ~linkage in
   let top_sorted_cms = Cm_files.top_sorted_cms cm_files ~mode in
   let fdo_linker_script = Fdo.Linker_script.create cctx (Path.build exe) in
-  let open Memo.O in
   let* action_with_targets =
     let ocaml_flags = Ocaml_flags.get (Compilation_context.flags cctx) (Ocaml mode) in
     let prefix =
@@ -266,7 +266,6 @@ let link_many
   ~promote
   cctx
   =
-  let open Memo.O in
   let o_files =
     match o_files with
     | None -> Mode.Map.empty
@@ -361,7 +360,6 @@ let build_and_link_many
   ~promote
   cctx
   =
-  let open Memo.O in
   let* () = Module_compilation.build_all cctx in
   let* () =
     Memo.when_ (Compilation_context.bin_annot cctx) (fun () ->

src/dune_rules/fdo.ml

@@ -1,4 +1,5 @@
 open Import
+open Memo.O
 
 type phase =
   | All
@@ -44,7 +45,6 @@ let ocamlfdo_binary sctx dir =
 (* FDO flags are context dependent. *)
 let get_flags var =
   let f (ctx : Context.t) =
-    let open Memo.O in
     let+ env = Context.installed_env ctx in
     Env.get env var |> Option.value ~default:"" |> String.extract_blank_separated_words
   in
@@ -165,7 +165,6 @@ module Linker_script = struct
       | Some fdo_profile_path -> Command.Args.S [ A "-fdo-profile"; Dep fdo_profile_path ]
       | None -> As []
     in
-    let open Memo.O in
     let ocamlfdo_binary = ocamlfdo_binary sctx dir in
     let ocamlfdo_linker_script_flags =
       Action_builder.of_memo @@ ocamlfdo_linker_script_flags ctx
@@ -202,7 +201,6 @@ module Linker_script = struct
   ;;
 
   let flags t =
-    let open Memo.O in
     let open Command.Args in
     match t with
     | None -> Memo.return (As [])

src/dune_rules/fetch_rules.ml

@@ -232,7 +232,6 @@ let gen_rules_for_checksum_or_url (loc_url, (url : OpamUrl.t)) checksum =
       action ~target ~kind:`File
       |> Action_builder.With_targets.add ~file_targets:[ target ]
     in
-    let open Memo.O in
     let+ () = rule dir_rule
     and+ () = rule file_rule in
     ()

src/dune_rules/findlib.ml

@@ -1,4 +1,5 @@
 open Import
+open Memo.O
 module Opam_package = Package
 module P = Ocaml.Variant
 module Ps = Ocaml.Variant.Set
@@ -76,7 +77,6 @@ module DB = struct
   let create ~paths ~(lib_config : Lib_config.t) =
     let stdlib_dir = lib_config.stdlib_dir in
     let ext_lib = lib_config.ext_lib in
-    let open Memo.O in
     let+ builtins =
       let version = lib_config.ocaml_version in
       Meta.builtins ~stdlib_dir ~version
@@ -483,7 +483,6 @@ type t = DB.t
 let create =
   Per_context.create_by_name ~name:"findlib" (fun context ->
     Memo.lazy_ (fun () ->
-      let open Memo.O in
       let* context = Context.DB.get context in
       let* paths = Context.findlib_paths context
       and* lib_config =

src/dune_rules/foreign_rules.ml

@@ -49,7 +49,6 @@ let foreign_flags_env =
         let+ ocaml = Context.ocaml context in
         default_context_flags (Context.build_context context) ocaml.ocaml_config ~project)
       ~f:(fun ~parent expander (env : Dune_env.config) ->
-        let open Memo.O in
         let+ parent = parent in
         let foreign_flags lang =
           Foreign_language.Dict.get env.foreign_flags lang