diff --git a/infer/src/base/ResultsDir.ml b/infer/src/base/ResultsDir.ml
index 64c8ddab2..e555b0a63 100644
--- a/infer/src/base/ResultsDir.ml
+++ b/infer/src/base/ResultsDir.ml
@@ -8,6 +8,77 @@ open! IStd
 open PolyVariantEqual
 module L = Logging
 
+module RunState = struct
+  let run_time_string = Time.now () |> Time.to_string
+
+  let state0 =
+    let open Runstate_t in
+    { run_sequence= []
+    ; results_dir_format=
+        Printf.sprintf "db_filename: %s\ndb_schema: %s" ResultsDatabase.database_filename
+          ResultsDatabase.schema_hum
+    ; should_merge_capture= false }
+
+
+  let state : Runstate_t.t ref = ref state0
+
+  let state_filename = ".infer_runstate.json"
+
+  let state_file_path = Config.results_dir ^/ state_filename
+
+  let store () =
+    Utils.with_file_out state_file_path ~f:(fun oc ->
+        Runstate_j.string_of_t !state |> Out_channel.output_string oc )
+
+
+  let load_and_validate () =
+    let error msg =
+      Printf.ksprintf
+        (fun err_msg ->
+          Error
+            (Printf.sprintf
+               "'%s' already exists but it is not an empty directory and it does not look like an \
+                infer results directory:\n\
+               \  %s\n\
+                Was it created using an older version of infer?" Config.results_dir err_msg) )
+        msg
+    in
+    if PolyVariantEqual.(Sys.file_exists state_file_path <> `Yes) then
+      error "save state not found: '%s' does not exist" state_file_path
+    else
+      match Atdgen_runtime.Util.Json.from_file Runstate_j.read_t state_file_path with
+      | {Runstate_t.results_dir_format} as loaded_state
+        when String.equal !state.Runstate_t.results_dir_format results_dir_format ->
+          state := loaded_state ;
+          Ok ()
+      | {Runstate_t.results_dir_format} ->
+          error "Incompatible formats: found\n  %s\n\nbut expected this format:\n  %s\n\n"
+            results_dir_format !state.Runstate_t.results_dir_format
+      | exception e ->
+          error "could not read the save state '%s': %s" state_file_path (Exn.to_string e)
+
+
+  let reset () = state := state0
+
+  let set_merge_capture onoff =
+    state := {!state with Runstate_t.should_merge_capture= onoff} ;
+    (* store change to the runstate *)
+    store ()
+
+
+  let get_merge_capture () = !state.Runstate_t.should_merge_capture
+
+  let add_run_to_sequence () =
+    let run =
+      { Runstate_t.infer_version= Version.{Runstate_t.major; minor; patch; commit}
+      ; date= run_time_string
+      ; command= Config.command }
+    in
+    state := {!state with Runstate_t.run_sequence= run :: !state.run_sequence} ;
+    (* store change to the runstate *)
+    store ()
+end
+
 let results_dir_dir_markers = [Config.results_dir ^/ Config.specs_dir_name]
 
 let is_results_dir ~check_correct_version () =
diff --git a/infer/src/base/ResultsDir.mli b/infer/src/base/ResultsDir.mli
index 58f3a5db4..b8f66826e 100644
--- a/infer/src/base/ResultsDir.mli
+++ b/infer/src/base/ResultsDir.mli
@@ -7,6 +7,17 @@
 
 open! IStd
 
+module RunState : sig
+  val add_run_to_sequence : unit -> unit
+  (** add an entry with the current run date *)
+
+  val set_merge_capture : bool -> unit
+  (** update the 'merge after capture' smart option *)
+
+  val get_merge_capture : unit -> bool
+  (** fetch the value of the 'merge after capture' smart option *)
+end
+
 val assert_results_dir : string -> unit
 (** Check that the results dir exists and sets up logging, the database, etc. *)
 
diff --git a/infer/src/base/RunState.ml b/infer/src/base/RunState.ml
deleted file mode 100644
index 57b7ea735..000000000
--- a/infer/src/base/RunState.ml
+++ /dev/null
@@ -1,72 +0,0 @@
-(*
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *)
-
-open! IStd
-
-let run_time_string = Time.now () |> Time.to_string
-
-let state0 =
-  let open Runstate_t in
-  { run_sequence= []
-  ; results_dir_format=
-      Printf.sprintf "db_filename: %s\ndb_schema: %s" ResultsDatabase.database_filename
-        ResultsDatabase.schema_hum
-  ; should_merge_capture= false }
-
-
-let state : Runstate_t.t ref = ref state0
-
-let add_run_to_sequence () =
-  let run =
-    { Runstate_t.infer_version= Version.{Runstate_t.major; minor; patch; commit}
-    ; date= run_time_string
-    ; command= Config.command }
-  in
-  Runstate_t.(state := {!state with run_sequence= run :: !state.run_sequence})
-
-
-let state_filename = ".infer_runstate.json"
-
-let state_file_path = Config.results_dir ^/ state_filename
-
-let store () =
-  Utils.with_file_out state_file_path ~f:(fun oc ->
-      Runstate_j.string_of_t !state |> Out_channel.output_string oc )
-
-
-let load_and_validate () =
-  let error msg =
-    Printf.ksprintf
-      (fun err_msg ->
-        Error
-          (Printf.sprintf
-             "'%s' already exists but it is not an empty directory and it does not look like an \
-              infer results directory:\n\
-             \  %s\n\
-              Was it created using an older version of infer?" Config.results_dir err_msg) )
-      msg
-  in
-  if PolyVariantEqual.(Sys.file_exists state_file_path <> `Yes) then
-    error "save state not found: '%s' does not exist" state_file_path
-  else
-    match Atdgen_runtime.Util.Json.from_file Runstate_j.read_t state_file_path with
-    | {Runstate_t.results_dir_format} as loaded_state
-      when String.equal !state.Runstate_t.results_dir_format results_dir_format ->
-        state := loaded_state ;
-        Ok ()
-    | {Runstate_t.results_dir_format} ->
-        error "Incompatible formats: found\n  %s\n\nbut expected this format:\n  %s\n\n"
-          results_dir_format !state.Runstate_t.results_dir_format
-    | exception e ->
-        error "could not read the save state '%s': %s" state_file_path (Exn.to_string e)
-
-
-let reset () = state := state0
-
-let set_merge_capture onoff = Runstate_t.(state := {!state with should_merge_capture= onoff})
-
-let get_merge_capture () = !state.Runstate_t.should_merge_capture
diff --git a/infer/src/base/RunState.mli b/infer/src/base/RunState.mli
deleted file mode 100644
index 3e486ad8f..000000000
--- a/infer/src/base/RunState.mli
+++ /dev/null
@@ -1,26 +0,0 @@
-(*
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *)
-
-open! IStd
-
-val add_run_to_sequence : unit -> unit
-(** add an entry with the current run date *)
-
-val set_merge_capture : bool -> unit
-(** update the 'merge after capture' smart option *)
-
-val get_merge_capture : unit -> bool
-(** fetch the value of the 'merge after capture' smart option *)
-
-val store : unit -> unit
-(** save the current state to disk *)
-
-val load_and_validate : unit -> (unit, string) Result.t
-(** attempt to load state from disk *)
-
-val reset : unit -> unit
-(** reset the in-memory state to what it would be if this were a fresh run of infer *)
diff --git a/infer/src/infer.ml b/infer/src/infer.ml
index c083c1e6d..2c5850c07 100644
--- a/infer/src/infer.ml
+++ b/infer/src/infer.ml
@@ -61,7 +61,7 @@ let setup () =
       ResultsDir.assert_results_dir "please run an infer analysis first" ) ;
   db_start () ;
   NullsafeInit.init () ;
-  if CLOpt.is_originator then (RunState.add_run_to_sequence () ; RunState.store ()) ;
+  if CLOpt.is_originator then ResultsDir.RunState.add_run_to_sequence () ;
   ()
 
 
diff --git a/infer/src/integration/BuckGenrule.ml b/infer/src/integration/BuckGenrule.ml
index 43d2922a3..51943414d 100644
--- a/infer/src/integration/BuckGenrule.ml
+++ b/infer/src/integration/BuckGenrule.ml
@@ -147,5 +147,5 @@ let capture build_cmd =
     run_buck_capture updated_buck_cmd ;
     infer_deps_of_build_report build_report_file ;
     L.progress "Genrule capture took %a.@." Mtime.Span.pp (Mtime_clock.count time0) ;
-    RunState.set_merge_capture true ;
-    RunState.store ()
+    ResultsDir.RunState.set_merge_capture true ;
+    ()
diff --git a/infer/src/integration/Driver.ml b/infer/src/integration/Driver.ml
index 247705032..8e58fe2d5 100644
--- a/infer/src/integration/Driver.ml
+++ b/infer/src/integration/Driver.ml
@@ -141,8 +141,8 @@ let buck_capture build_cmd =
   in
   Option.iter prog_build_cmd_opt ~f:(fun (prog, buck_build_cmd) ->
       L.progress "Capturing in buck mode...@." ;
-      if Option.exists ~f:BuckMode.is_clang_flavors Config.buck_mode then (
-        RunState.set_merge_capture true ; RunState.store () ) ;
+      if Option.exists ~f:BuckMode.is_clang_flavors Config.buck_mode then
+        ResultsDir.RunState.set_merge_capture true ;
       Buck.clang_flavor_capture ~prog ~buck_build_cmd )
 
 
@@ -283,15 +283,14 @@ let analyze_and_report ?suppress_console_report ~changed_files mode =
         (* if doing capture + analysis of buck with flavors, we always need to merge targets before the analysis phase *)
         true
     | Analyze | BuckGenruleMaster _ ->
-        RunState.get_merge_capture ()
+        ResultsDir.RunState.get_merge_capture ()
     | _ ->
         false
   in
   if should_merge then (
     if Config.export_changed_functions then MergeCapture.merge_changed_functions () ;
     MergeCapture.merge_captured_targets () ;
-    RunState.set_merge_capture false ;
-    RunState.store () ) ;
+    ResultsDir.RunState.set_merge_capture false ) ;
   if should_analyze then
     if SourceFiles.is_empty () && Config.capture then error_nothing_to_analyze mode
     else (