diff --git a/bin/exec.ml b/bin/exec.ml
index d481de4ab23b..54db071fc4b8 100644
--- a/bin/exec.ml
+++ b/bin/exec.ml
@@ -149,7 +149,7 @@ module Cli_item = struct
     | _ -> String s
   ;;
 
-  let parse_cli_item s =
+  let parse s =
     match parse_program_name s with
     | Sw _ as n -> Program n
     | String s -> Argument s
@@ -189,7 +189,7 @@ module Cli_item = struct
   ;;
 
   let program_name_conv = Arg.conv ((fun s -> Ok (parse_program_name s)), pp_program_name)
-  let conv = Arg.conv ((fun s -> Ok (parse_cli_item s)), pp)
+  let conv = Arg.conv ((fun s -> Ok (parse s)), pp)
 end
 
 let not_found ~dir ~prog =
@@ -325,7 +325,7 @@ module Exec_context = struct
     let* get_path_and_build_if_necessary = get_path_and_build_if_necessary in
     let* env = env in
     let* expand_cli_item = expand_cli_item in
-    let* args = args |> List.map ~f:expand_cli_item |> Memo.all |> Memo.run in
+    let* args = args |> Memo.parallel_map ~f:expand_cli_item |> Memo.run in
     let command_to_exec =
       { Command_to_exec.get_path_and_build_if_necessary =
           (fun () ->