rescript-lang · cristianoc · Jan 14, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -20,6 +20,8 @@
 
 #### :bug: Bug fix
 
+- Reanalyze: fix reactive/server stale results when cross-file references change without changing dead declarations (non-transitive mode). https://github.com/rescript-lang/rescript/pull/8173
+
 #### :memo: Documentation
 
 #### :nail_care: Polish

diff --git a/analysis/reanalyze/README.md b/analysis/reanalyze/README.md
@@ -60,6 +60,8 @@ rescript-tools reanalyze -config -reactive -timing -runs 3
 | `-churn n` | Remove/re-add n random files between runs (incremental correctness/perf testing) |
 | `-timing` | Report timing of analysis phases |
 | `-mermaid` | Output Mermaid diagram of reactive pipeline (to stderr) |
+| `-transitive` | Force transitive reporting (overrides rescript.json) |
+| `-no-transitive` | Disable transitive reporting (overrides rescript.json) |
 | `-debug` | Print debug information |
 | `-json` | Output in JSON format |
 | `-ci` | Internal flag for CI mode |
@@ -68,6 +70,18 @@ rescript-tools reanalyze -config -reactive -timing -runs 3
 
 See [ARCHITECTURE.md](ARCHITECTURE.md) for details on the analysis pipeline.
 
+### Regenerating the checked-in reactive pipeline diagram
+
+`analysis/reanalyze/diagrams/reactive-pipeline-full.mmd` is generated from the live reactive graph printer (`Reactive.to_mermaid()`), and **we check in the non-transitive (`-no-transitive`) variant** because that is where cross-file `hasRefBelow` suppression is relevant (and where reactive invalidation bugs are easiest to spot).
+
+To regenerate it:
+
+```bash
+# Run from any ReScript project (so -config works), then capture stderr:
+rescript-tools reanalyze -config -reactive -no-transitive -mermaid \
+  >/dev/null 2> analysis/reanalyze/diagrams/reactive-pipeline-full.mmd
+```
+
 The DCE analysis is structured as a pure pipeline:
 
 1. **MAP** - Process each `.cmt` file independently → per-file data

diff --git a/analysis/reanalyze/diagrams/reactive-pipeline-full.mmd b/analysis/reanalyze/diagrams/reactive-pipeline-full.mmd
@@ -25,7 +25,6 @@ graph TD
     solver.live_decls[solver.live_decls]
     type_deps.impl_decls[type_deps.impl_decls]
     liveness.all_roots[liveness.all_roots]
-    solver.dead_modules[solver.dead_modules]
     liveness.external_type_refs[liveness.external_type_refs]
     decl_refs.combined[decl_refs.combined]
     type_refs_from[type_refs_from]
@@ -34,20 +33,20 @@ graph TD
     liveness.external_value_refs[liveness.external_value_refs]
     liveness.value_refs_from[liveness.value_refs_from]
     value_refs_from[value_refs_from]
-    solver.modules_with_dead[solver.modules_with_dead]
     solver.dead_decls[solver.dead_decls]
     exception_refs_collection[exception_refs_collection]
     type_deps.intf_decls[type_deps.intf_decls]
     file_data_collection[file_data_collection]
     solver.dead_module_issues[solver.dead_module_issues]
     decl_refs.with_type_refs[decl_refs.with_type_refs]
-    solver.modules_with_live[solver.modules_with_live]
     decl_refs.type_decl_refs[decl_refs.type_decl_refs]
     files[files]
     solver.modules_with_reported[solver.modules_with_reported]
     liveness.externally_referenced[liveness.externally_referenced]
     liveness.edges[liveness.edges]
+    solver.refs_token[solver.refs_token]
     liveness.live[liveness.live]
+    solver.dead_modules_empty[solver.dead_modules_empty]
     decls[decls]
     type_deps.intf_to_impl_refs_join{join}
     liveness.external_value_refs_join{join}
@@ -57,7 +56,6 @@ graph TD
     exc_refs.resolved_refs_join{join}
     type_deps.combined_refs_to_union{union}
     liveness.externally_referenced_union{union}
-    solver.dead_modules_join{join}
     liveness.all_roots_union{union}
     solver.dead_module_issues_join{join}
     solver.dead_decls_join{join}
@@ -68,6 +66,7 @@ graph TD
     decl_refs.with_value_refs_join{join}
     liveness.type_refs_from_union{union}
     type_deps.impl_needing_path2_join{join}
+    solver.issues_by_file_join{join}
     liveness.external_type_refs_join{join}
     liveness.live_fp{fixpoint}
     decl_refs.type_decl_refs_join{join}
@@ -103,24 +102,22 @@ graph TD
     type_deps.decl_by_path -->|flatMap| type_deps.same_path_refs
     type_deps.u2 --> type_deps.combined_refs_to_union
     solver.live_decls --> solver.incorrect_dead_decls_join
-    solver.live_decls -->|flatMap| solver.modules_with_live
     type_deps.impl_decls --> type_deps.impl_needing_path2_join
     type_deps.impl_decls --> type_deps.impl_to_intf_refs_join
     liveness.all_roots --> liveness.live_fp
-    solver.dead_modules --> solver.dead_module_issues_join
     liveness.external_type_refs --> liveness.externally_referenced_union
     decl_refs.combined -->|flatMap| liveness.edges
     type_refs_from --> liveness.type_refs_from_union
     liveness.type_refs_from --> liveness.external_type_refs_join
     liveness.type_refs_from --> decl_refs.type_decl_refs_join
-    solver.dead_decls_by_file -->|flatMap| solver.issues_by_file
+    solver.dead_decls_by_file --> solver.issues_by_file_join
     liveness.external_value_refs --> liveness.externally_referenced_union
     liveness.value_refs_from --> liveness.external_value_refs_join
     liveness.value_refs_from --> decl_refs.value_decl_refs_join
+    value_refs_from -->|flatMap| solver.refs_token
     value_refs_from --> liveness.value_refs_from_union
-    solver.modules_with_dead --> solver.dead_modules_join
     solver.dead_decls -->|flatMap| solver.dead_decls_by_file
-    solver.dead_decls -->|flatMap| solver.modules_with_dead
+    solver.dead_decls -->|flatMap| solver.dead_modules_empty
     exception_refs_collection --> exc_refs.resolved_refs_join
     type_deps.intf_decls --> type_deps.intf_to_impl_refs_join
     file_data_collection -->|flatMap| files
@@ -131,13 +128,14 @@ graph TD
     file_data_collection -->|flatMap| annotations
     file_data_collection -->|flatMap| decls
     decl_refs.with_type_refs --> decl_refs.combined_join
-    solver.modules_with_live --> solver.dead_modules_join
     decl_refs.type_decl_refs --> decl_refs.with_type_refs_join
     solver.modules_with_reported --> solver.dead_module_issues_join
     liveness.externally_referenced --> liveness.all_roots_union
     liveness.edges --> liveness.live_fp
+    solver.refs_token --> solver.issues_by_file_join
     liveness.live --> solver.live_decls_join
     liveness.live --> solver.dead_decls_join
+    solver.dead_modules_empty --> solver.dead_module_issues_join
     decls --> solver.live_decls_join
     decls --> solver.dead_decls_join
     decls --> liveness.annotated_roots_join
@@ -158,7 +156,6 @@ graph TD
     exc_refs.resolved_refs_join --> exc_refs.resolved_refs
     type_deps.combined_refs_to_union --> type_deps.combined_refs_to
     liveness.externally_referenced_union --> liveness.externally_referenced
-    solver.dead_modules_join --> solver.dead_modules
     liveness.all_roots_union --> liveness.all_roots
     solver.dead_module_issues_join --> solver.dead_module_issues
     solver.dead_decls_join --> solver.dead_decls
@@ -169,6 +166,7 @@ graph TD
     decl_refs.with_value_refs_join --> decl_refs.with_value_refs
     liveness.type_refs_from_union --> liveness.type_refs_from
     type_deps.impl_needing_path2_join --> type_deps.impl_needing_path2
+    solver.issues_by_file_join --> solver.issues_by_file
     liveness.external_type_refs_join --> liveness.external_type_refs
     liveness.live_fp --> liveness.live
     decl_refs.type_decl_refs_join --> decl_refs.type_decl_refs
@@ -180,7 +178,7 @@ graph TD
     classDef joinClass fill:#e6f3ff,stroke:#0066cc
     classDef unionClass fill:#fff0e6,stroke:#cc6600
     classDef fixpointClass fill:#e6ffe6,stroke:#006600
-    class decl_refs.with_type_refs_join,decl_refs.combined_join,decl_refs.type_decl_refs_join,liveness.external_type_refs_join,type_deps.impl_needing_path2_join,decl_refs.with_value_refs_join,solver.live_decls_join,type_deps.impl_to_intf_refs_join,decl_refs.value_decl_refs_join,liveness.annotated_roots_join,solver.dead_decls_join,solver.dead_module_issues_join,solver.dead_modules_join,exc_refs.resolved_refs_join,solver.incorrect_dead_decls_join,type_deps.impl_to_intf_refs_path2_join,liveness.external_value_refs_join,type_deps.intf_to_impl_refs_join joinClass
+    class decl_refs.with_type_refs_join,decl_refs.combined_join,decl_refs.type_decl_refs_join,liveness.external_type_refs_join,solver.issues_by_file_join,type_deps.impl_needing_path2_join,decl_refs.with_value_refs_join,solver.live_decls_join,type_deps.impl_to_intf_refs_join,decl_refs.value_decl_refs_join,liveness.annotated_roots_join,solver.dead_decls_join,solver.dead_module_issues_join,exc_refs.resolved_refs_join,solver.incorrect_dead_decls_join,type_deps.impl_to_intf_refs_path2_join,liveness.external_value_refs_join,type_deps.intf_to_impl_refs_join joinClass
     class type_deps.u1_union,type_deps.u2_union,liveness.type_refs_from_union,liveness.all_roots_union,liveness.externally_referenced_union,type_deps.combined_refs_to_union,liveness.value_refs_from_union unionClass
     class liveness.live_fp fixpointClass
 
diff --git a/analysis/reanalyze/src/ReactiveSolver.ml b/analysis/reanalyze/src/ReactiveSolver.ml
@@ -121,53 +121,70 @@ let create ~(decls : (Lexing.position, Decl.t) Reactive.t)
 
   let transitive = config.DceConfig.run.transitive in
 
-  (* Reactive per-file issues - recomputed when dead_decls_by_file changes.
-     Returns (file, (value_issues, modules_with_reported_values)) where
-     modules_with_reported_values are modules that have at least one reported dead value.
-     Module issues are generated separately in collect_issues using dead_modules. *)
+  (* Reactive per-file issues.
+     IMPORTANT: in non-transitive mode, warning emission depends on hasRefBelow,
+     which depends on value_refs_from (cross-file refs). So we must recompute
+     issues when refs change, not only when the file's dead decls change. *)
+  let issues_for_file (_file : string) decls =
+    (* Track modules that have reported values *)
+    let modules_with_values : (Name.t, unit) Hashtbl.t = Hashtbl.create 8 in
+    (* shouldReport checks annotations reactively *)
+    let shouldReport (decl : Decl.t) =
+      match Reactive.get annotations decl.pos with
+      | Some FileAnnotations.Live -> false
+      | Some FileAnnotations.GenType -> false
+      | Some FileAnnotations.Dead -> false
+      | None -> true
+    in
+    (* Don't emit module issues here - track modules for later *)
+    let checkModuleDead ~fileName:_ moduleName =
+      Hashtbl.replace modules_with_values moduleName ();
+      None (* Module issues generated separately *)
+    in
+    (* hasRefBelow: check if decl has any ref from "below" (including cross-file refs) *)
+    let hasRefBelow =
+      if transitive then fun _ -> false
+      else
+        match value_refs_from with
+        | None -> fun _ -> false
+        | Some refs_from ->
+          (* Must iterate ALL refs since cross-file refs also count as "below" *)
+          DeadCommon.make_hasRefBelow ~transitive
+            ~iter_value_refs_from:(fun f -> Reactive.iter f refs_from)
+    in
+    (* Sort within file and generate issues *)
+    let sorted = decls |> List.fast_sort Decl.compareForReporting in
+    let reporting_ctx = DeadCommon.ReportingContext.create () in
+    let file_issues =
+      sorted
+      |> List.concat_map (fun decl ->
+             DeadCommon.reportDeclaration ~config ~hasRefBelow ~checkModuleDead
+               ~shouldReport reporting_ctx decl)
+    in
+    let modules_list =
+      Hashtbl.fold (fun m () acc -> m :: acc) modules_with_values []
+    in
+    (file_issues, modules_list)
+  in
   let issues_by_file =
-    Reactive.flatMap ~name:"solver.issues_by_file" dead_decls_by_file
-      ~f:(fun file decls ->
-        (* Track modules that have reported values *)
-        let modules_with_values : (Name.t, unit) Hashtbl.t = Hashtbl.create 8 in
-        (* shouldReport checks annotations reactively *)
-        let shouldReport (decl : Decl.t) =
-          match Reactive.get annotations decl.pos with
-          | Some FileAnnotations.Live -> false
-          | Some FileAnnotations.GenType -> false
-          | Some FileAnnotations.Dead -> false
-          | None -> true
-        in
-        (* Don't emit module issues here - track modules for later *)
-        let checkModuleDead ~fileName:_ moduleName =
-          Hashtbl.replace modules_with_values moduleName ();
-          None (* Module issues generated separately *)
-        in
-        (* hasRefBelow: check if decl has any ref from "below" (including cross-file refs) *)
-        let hasRefBelow =
-          if transitive then fun _ -> false
-          else
-            match value_refs_from with
-            | None -> fun _ -> false
-            | Some refs_from ->
-              (* Must iterate ALL refs since cross-file refs also count as "below" *)
-              DeadCommon.make_hasRefBelow ~transitive
-                ~iter_value_refs_from:(fun f -> Reactive.iter f refs_from)
-        in
-        (* Sort within file and generate issues *)
-        let sorted = decls |> List.fast_sort Decl.compareForReporting in
-        let reporting_ctx = DeadCommon.ReportingContext.create () in
-        let file_issues =
-          sorted
-          |> List.concat_map (fun decl ->
-                 DeadCommon.reportDeclaration ~config ~hasRefBelow
-                   ~checkModuleDead ~shouldReport reporting_ctx decl)
-        in
-        let modules_list =
-          Hashtbl.fold (fun m () acc -> m :: acc) modules_with_values []
-        in
-        [(file, (file_issues, modules_list))])
-      ()
+    match (transitive, value_refs_from) with
+    | true, _ | false, None ->
+      Reactive.flatMap ~name:"solver.issues_by_file" dead_decls_by_file
+        ~f:(fun file decls -> [(file, issues_for_file file decls)])
+        ()
+    | false, Some refs_from ->
+      (* Create a singleton "refs token" that changes whenever refs_from changes,
+         and join every file against it so per-file issues recompute. *)
+      let refs_token =
+        Reactive.flatMap ~name:"solver.refs_token" refs_from
+          ~f:(fun _posFrom _targets -> [((), ())])
+          ~merge:(fun _ _ -> ())
+          ()
+      in
+      Reactive.join ~name:"solver.issues_by_file" dead_decls_by_file refs_token
+        ~key_of:(fun _file _decls -> ())
+        ~f:(fun file decls _token_opt -> [(file, issues_for_file file decls)])
+        ()
   in
 
   (* Reactive incorrect @dead: live decls with @dead annotation *)

diff --git a/analysis/reanalyze/src/Reanalyze.ml b/analysis/reanalyze/src/Reanalyze.ml
@@ -644,6 +644,8 @@ let runAnalysisAndReport ~cmtRoot =
 let parse_argv (argv : string array) : string option =
   let analysisKindSet = ref false in
   let cmtRootRef = ref None in
+  (* CLI override for transitive mode (overrides rescript.json if provided). *)
+  let transitive_override : bool option ref = ref None in
   let usage = "reanalyze version " ^ Version.version in
   let versionAndExit () =
     print_endline usage;
@@ -678,6 +680,14 @@ let parse_argv (argv : string array) : string option =
          path" );
       ("-ci", Unit (fun () -> Cli.ci := true), "Internal flag for use in CI");
       ("-config", Unit setConfig, "Read the analysis mode from rescript.json");
+      ( "-transitive",
+        Unit (fun () -> transitive_override := Some true),
+        "Force transitive reporting (overrides rescript.json \
+         reanalyze.transitive)" );
+      ( "-no-transitive",
+        Unit (fun () -> transitive_override := Some false),
+        "Disable transitive reporting (overrides rescript.json \
+         reanalyze.transitive)" );
       ("-dce", Unit (fun () -> setDCE None), "Eperimental DCE");
       ("-debug", Unit (fun () -> Cli.debug := true), "Print debug information");
       ( "-dce-cmt",
@@ -767,6 +777,9 @@ let parse_argv (argv : string array) : string option =
   let current = ref 0 in
   Arg.parse_argv ~current argv speclist print_endline usage;
   if !analysisKindSet = false then setConfig ();
+  (match !transitive_override with
+  | None -> ()
+  | Some b -> RunConfig.transitive b);
   !cmtRootRef
 
 (** Default socket location invariant: