added case to load libraries of executables

Author: kiranandcode

src/dune_rules/utop.ml

@@ -93,6 +93,57 @@ let libs_and_ppx_under_dir sctx ~db ~dir =
                     , pps )
                 else
                   (acc, pps))
+            | Dune_file.Executables exes -> (
+                let* libs =
+                  let open Memo.Build.O in
+                  let* compile_info =
+                    let project = Scope.project d.scope in
+                    let dune_version = Dune_project.dune_version project in
+                    let+ pps =
+                      Resolve.Build.read_memo_build
+                        (Preprocess.Per_module.with_instrumentation
+                           exes.buildable.preprocess
+                           ~instrumentation_backend:
+                             (Lib.DB.instrumentation_backend (Scope.libs d.scope)))
+                      >>| Preprocess.Per_module.pps in
+                    Lib.DB.resolve_user_written_deps_for_exes
+                      db exes.names exes.buildable.libraries
+                      ~pps ~dune_version
+                      ~allow_overlaps:exes.buildable.allow_overlapping_dependencies
+                      ~forbidden_libraries:exes.forbidden_libraries in
+                  let+ available = Lib.Compile.direct_requires compile_info in
+                  Resolve.peek available in
+                match libs with
+                | Error () -> Memo.Build.return (acc, pps)
+                | Ok libs ->
+                  Memo.Build.List.fold_left libs
+                    ~init:(acc,pps)
+                    ~f:(fun (acc, pps) lib ->
+                      let info = Lib.info lib in
+                      (* Only select libraries that are not implementations.
+                         Implementations are selected using the default implementation
+                         feature. *)
+                      let not_impl = Option.is_none (Lib_info.implements info) in
+                      if not_impl
+                      then
+                        match Lib_info.kind info with
+                        | Lib_kind.Ppx_rewriter _
+                        | Ppx_deriver _ ->
+                          Memo.Build.return
+                          ( Appendable_list.( @ ) (Appendable_list.singleton lib) acc
+                          , Appendable_list.( @ )
+                              (Appendable_list.singleton
+                                 (Lib_info.loc info, Lib_info.name info))
+                              pps )
+                        | Normal ->
+                          Memo.Build.return
+                          ( Appendable_list.( @ ) (Appendable_list.singleton lib) acc
+                          , pps )
+                      else
+                        Memo.Build.return
+                        (acc, pps)
+                    )
+              )
             | _ -> Memo.Build.return (acc, pps)))
     >>| fun (libs, pps) ->
     (Appendable_list.to_list libs, Appendable_list.to_list pps)