Compiler: fix inlining 2106

compiler/lib/duplicate.ml

@@ -60,8 +60,15 @@ let rec blocks_to_rename p pc lst =
     p.blocks
     lst
 
-let closure p ~f ~params ~cont =
-  let s = Subst.from_map (bound_variables p ~f ~params ~cont) in
+let closure p ~f ~params ~cont live_vars =
+  let s =
+    let map = bound_variables p ~f ~params ~cont in
+    fun x ->
+      try Var.Map.find x map
+      with Not_found ->
+        live_vars.(Var.idx x) <- live_vars.(Var.idx x) + 1;
+        x
+  in
   let pc, args = cont in
   let blocks = blocks_to_rename p pc [] in
   let free_pc, m =

compiler/lib/duplicate.mli

@@ -21,6 +21,7 @@ val closure :
   -> f:Code.Var.t
   -> params:Code.Var.t list
   -> cont:int * Code.Var.t list
+  -> int Array.t
   -> Code.program * Code.Var.t * Code.Var.t list * (int * Code.Var.t list)
 (** Given a program and a closure [f] -- defined by its name,
     parameters, and its continuation --, return a program with a copy

compiler/lib/inline.ml

@@ -643,7 +643,9 @@ and inline_function ~context i x f args rem state =
     let p, params, cont =
       if context.live_vars.(Var.idx f) > 0
       then (
-        let p, _f, params, cont = Duplicate.closure p ~f ~params ~cont in
+        let p, _f, params, cont =
+          Duplicate.closure p ~f ~params ~cont context.live_vars
+        in
         (* It's ok to ignore the [_f] because the function is not recursive *)
         assert (not info.recursive);
         p, params, cont)

compiler/tests-compiler/dune.inc

@@ -464,6 +464,21 @@
  (preprocess
   (pps ppx_expect)))
 
+(library
+ ;; compiler/tests-compiler/gh2106.ml
+ (name gh2106_15)
+ (enabled_if true)
+ (modules gh2106)
+ (libraries js_of_ocaml_compiler unix str jsoo_compiler_expect_tests_helper)
+ (inline_tests
+  (enabled_if true)
+  (deps
+   (file %{project_root}/compiler/bin-js_of_ocaml/js_of_ocaml.exe)
+   (file %{project_root}/compiler/bin-jsoo_minify/jsoo_minify.exe)))
+ (flags (:standard -open Jsoo_compiler_expect_tests_helper))
+ (preprocess
+  (pps ppx_expect)))
+
 (library
  ;; compiler/tests-compiler/gh747.ml
  (name gh747_15)

compiler/tests-compiler/gh2106.ml

@@ -0,0 +1,73 @@
+(* Js_of_ocaml compiler
+ * http://www.ocsigen.org/js_of_ocaml/
+ * Copyright (C) 2025 Hugo Heuzard
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, with linking exception;
+ * either version 2.1 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *)
+
+open Util
+
+let%expect_test "inlining" =
+  let p =
+    {|
+module X : sig
+end = struct
+  external fun_to_js : (unit -> unit) -> unit = "foo"
+
+  let[@tail_mod_cons] rec aux f = f () :: aux f
+
+  let map_to_list f = aux (fun x -> f x)
+
+  let embedded_input_file_handler _ =
+    fun_to_js (fun _ ->
+        let _ = map_to_list (fun _ -> assert false) in
+        ())
+
+  let _ = embedded_input_file_handler ()
+end
+   |}
+  in
+  let p = compile_and_parse ~flags:[ "--debug"; "js_assign" ] p in
+  print_program p;
+  [%expect
+    {|
+    (function(globalThis){
+       "use strict";
+       var
+        runtime = globalThis.jsoo_runtime,
+        caml_maybe_attach_backtrace = runtime.caml_maybe_attach_backtrace,
+        global_data = runtime.caml_get_global_data(),
+        Assert_failure = global_data.Assert_failure,
+        _a_ = [0, runtime.caml_string_of_jsbytes("test.ml"), 12, 38];
+       runtime.foo
+        (function(param){
+          function f(param){
+           throw caml_maybe_attach_backtrace([0, Assert_failure, _a_], 1);
+          }
+          var block = [0, f(0), 24029], dst = block, offset = 1;
+          for(;;){
+           var dst$0 = [0, f(0), 24029];
+           dst[offset + 1] = dst$0;
+           dst = dst$0;
+           offset = 1;
+          }
+         });
+       var X = [0], Test = [0, X];
+       runtime.caml_register_global(2, Test, "Test");
+       return;
+      }
+      (globalThis));
+    //end
+    |}]