rescript-lang · cknitt · Feb 27, 2026 · Feb 27, 2026 · Feb 2, 2026 · Feb 16, 2026
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -471,6 +471,8 @@ jobs:
   pkg-pr-new:
     needs:
       - build-compiler
+    outputs:
+      commit_sha: ${{ steps.publish.outputs.sha }}
     runs-on: ubuntu-24.04-arm
     steps:
       - name: Checkout
@@ -497,6 +499,7 @@ jobs:
           git diff --exit-code packages/artifacts.json
 
       - name: Publish packages to pkg.pr.new
+        id: publish
         run: |
           yarn dlx pkg-pr-new publish "." "./packages/@rescript/*"
 
@@ -528,6 +531,7 @@ jobs:
           fi
 
       - name: Use Node.js
+        if: steps.diffcheck.outputs.clean == 'false'
         uses: actions/setup-node@v6
         with:
           cache: yarn
@@ -586,9 +590,9 @@ jobs:
 
       - name: Install ReScript package
         run: |
-          COMMIT_SHA="${{ github.event.pull_request.head.sha || github.sha }}"
+          COMMIT_SHA="${{ needs.pkg-pr-new.outputs.commit_sha }}"
           npm i --no-audit \
-            "https://pkg.pr.new/rescript-lang/rescript@${COMMIT_SHA::7}"
+            "https://pkg.pr.new/rescript-lang/rescript@${COMMIT_SHA}"
         shell: bash
         working-directory: ${{ steps.tmp-dir.outputs.path }}
 
@@ -640,8 +644,8 @@ jobs:
 
       - name: Install ReScript package
         run: |
-          COMMIT_SHA="${{ github.event.pull_request.head.sha || github.sha }}"
-          pnpm i "https://pkg.pr.new/rescript-lang/rescript@${COMMIT_SHA::7}"
+          COMMIT_SHA="${{ needs.pkg-pr-new.outputs.commit_sha }}"
+          pnpm i "https://pkg.pr.new/rescript-lang/rescript@${COMMIT_SHA}"
         shell: bash
         working-directory: ${{ steps.tmp-dir.outputs.path }}
 
@@ -675,8 +679,8 @@ jobs:
 
       - name: Install ReScript package in rewatch/testrepo
         run: |
-          COMMIT_SHA="${{ github.event.pull_request.head.sha || github.sha }}"
-          yarn add "rescript@https://pkg.pr.new/rescript-lang/rescript@${COMMIT_SHA::7}"
+          COMMIT_SHA="${{ needs.pkg-pr-new.outputs.commit_sha }}"
+          yarn add "rescript@https://pkg.pr.new/rescript-lang/rescript@${COMMIT_SHA}"
         shell: bash
         working-directory: rewatch/testrepo
 

diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -10,6 +10,17 @@
 > - :nail_care: [Polish]
 > - :house: [Internal]
 
+# 12.2.0
+
+#### :boom: Breaking Change
+
+- Stdlib: Added Array.zip, Array.unzip, Array.zipBy, and Array.partition. https://github.com/rescript-lang/rescript/pull/8244
+
+#### :bug: Bug fix
+
+- Fix compiler crash (`Fatal error: Parmatch.all_record_args`) when matching empty dict/record patterns. https://github.com/rescript-lang/rescript/pull/8246
+- Fix `null` falling into the object branch instead of the wildcard when pattern matching on untagged variants with both `Object` and `null` cases. https://github.com/rescript-lang/rescript/pull/8253
+
 # 12.2.0-rc.1
 
 #### :boom: Breaking Change

diff --git a/LICENSE b/LICENSE
@@ -1,24 +1,11 @@
-Copyright (C) 2015-2016 Bloomberg Finance L.P.
-Copyright (C) 2017- Hongbo Zhang, Authors of ReScript
+This repository contains code under multiple licenses.
 
-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, either version 3 of the License, or
-(at your option) any later version.
+- compiler/: LGPL-3.0-or-later
+- compiler/syntax/: MIT
+- packages/@rescript/runtime/: MIT
+- rewatch/: MIT
 
-In addition to the permissions granted to you by the LGPL, you may combine
-or link a "work that uses the Library" with a publicly distributed version
-of this file to produce a combined library or application, then distribute
-that combined work under the terms of your choosing, with no requirement
-to comply with the obligations normally placed on you by section 4 of the
-LGPL version 3 (or the corresponding section of a later version of the LGPL
-should you choose to use a later version).
+See full license texts:
 
-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.
+- LGPL-3.0-or-later: COPYING.LESSER (and COPYING where applicable)
+- MIT: LICENSE.MIT
diff --git a/compiler/syntax/LICENSE → LICENSE.MIT b/compiler/syntax/LICENSE → LICENSE.MIT
@@ -1,6 +1,7 @@
 MIT License
 
-Copyright (c) 2020 - Authors of ReScript
+Copyright (c) 2015-2016 Bloomberg Finance L.P.
+Copyright (c) 2017- Hongbo Zhang, Authors of ReScript
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

diff --git a/README.md b/README.md
@@ -11,7 +11,7 @@
 <p align="center">
   <a href="https://www.npmjs.org/package/rescript"><img src="https://img.shields.io/npm/v/rescript?color=brightgreen&label=npm%20package" alt="Current npm package version." /></a>
   <a href="https://github.com/rescript-lang/rescript/actions"><img src="https://github.com//rescript-lang/rescript/workflows/CI/badge.svg" alt="Current Github Actions workflow status." /></a>
-  <a href="https://github.com/rescript-lang/rescript/blob/HEAD/LICENSE"><img src="https://img.shields.io/badge/License-LGPL%20v3-blue.svg" alt="ReScript is released under the LGPL license." /></a>
+  <a href="https://github.com/rescript-lang/rescript/blob/HEAD/LICENSE"><img src="https://img.shields.io/badge/License-LGPL%20%2B%20MIT-blue.svg" alt="ReScript uses both LGPL and MIT licenses." /></a>
   <a href="https://x.com/intent/follow?screen_name=rescriptlang"><img src="https://img.shields.io/badge/X-000000?style=flat&logo=x&logoColor=white" alt="Follow @rescriptlang on X" /></a>
   <a href="https://bsky.app/profile/rescript-lang.org"><img src="https://img.shields.io/badge/Bluesky-0285FF?logo=bluesky&logoColor=fff&style=flat" alt="Follow @rescriptlang on Bluesky" /></a>
 </p>
@@ -92,9 +92,14 @@ For discussions on ongoing development, see the [Development](https://forum.resc
 
 ## 📄 License
 
-ReScript is licensed under LGPL version 3, with relaxed rules about creating and distributing combined work. See the [LICENSE](LICENSE) file for details.
+ReScript uses multiple licenses in this monorepo:
 
-The ReScript parser (subdirectory `compiler/syntax`) is licensed under the [MIT License](compiler/syntax/LICENSE).
+- `compiler/`: LGPL-3.0-or-later
+- `compiler/syntax/`: MIT
+- `packages/@rescript/runtime/`: MIT
+- `rewatch/`: MIT
+
+See the repository license index in [`LICENSE`](LICENSE) and full license texts in [`COPYING.LESSER`](COPYING.LESSER) and [`LICENSE.MIT`](LICENSE.MIT).
 
 The `ninja` subdirectory contains the vendored [ninja](https://github.com/ninja-build/ninja) build system.
 Refer to its copyright and license notices for information about its licensing.

diff --git a/compiler/common/bs_version.ml b/compiler/common/bs_version.ml
@@ -21,5 +21,5 @@
  * 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. *)
-let version = "12.2.0-rc.1"
+let version = "12.2.0"
 let header = "// Generated by ReScript, PLEASE EDIT WITH CARE"
diff --git a/compiler/core/lam_compile.ml b/compiler/core/lam_compile.ml
@@ -818,6 +818,25 @@ let compile output_prefix =
       let not_typeof_clauses, typeof_clauses =
         List.partition clause_is_not_typeof clauses
       in
+      let has_object_typeof =
+        List.exists
+          (function
+            | Ast_untagged_variants.Untagged ObjectType, _ -> true
+            | _ -> false)
+          typeof_clauses
+      in
+      let has_array_case =
+        List.exists
+          (function
+            | Ast_untagged_variants.Untagged (InstanceType Array), _ -> true
+            | _ -> false)
+          not_typeof_clauses
+      in
+      (* When there's an ObjectType typeof case, null and arrays can
+         incorrectly match it (typeof null === typeof [] === "object").
+         Guard against them when they should fall through to default. *)
+      let needs_null_guard = has_object_typeof && has_null_case in
+      let needs_array_guard = has_object_typeof && not has_array_case in
       let rec build_if_chain remaining_clauses =
         match remaining_clauses with
         | ( Ast_untagged_variants.Untagged (InstanceType instance_type),
@@ -827,7 +846,21 @@ let compile output_prefix =
             (E.emit_check (IsInstanceOf (instance_type, Expr e)))
             switch_body
             ~else_:[build_if_chain rest]
-        | _ -> S.string_switch ?default ?declaration (E.typeof e) typeof_clauses
+        | _ -> (
+          let typeof_switch () =
+            S.string_switch ?default ?declaration (E.typeof e) typeof_clauses
+          in
+          let guard =
+            match (needs_null_guard, needs_array_guard) with
+            | true, true -> Some (E.or_ (E.is_null e) (E.is_array e))
+            | true, false -> Some (E.is_null e)
+            | false, true -> Some (E.is_array e)
+            | false, false -> None
+          in
+          match (guard, default) with
+          | Some guard, Some default_body ->
+            S.if_ guard default_body ~else_:[typeof_switch ()]
+          | _ -> typeof_switch ())
       in
       build_if_chain not_typeof_clauses
     in

diff --git a/compiler/ml/parmatch.ml b/compiler/ml/parmatch.ml
@@ -512,6 +512,7 @@ let extract_fields omegas arg =
 
 let all_record_args lbls =
   match lbls with
+  | [] -> []
   | (_, {lbl_all}, _, opt) :: _ ->
     let t =
       Array.map
@@ -560,7 +561,6 @@ let all_record_args lbls =
         t.(lbl.lbl_pos) <- x)
       lbls;
     Array.to_list t
-  | _ -> fatal_error "Parmatch.all_record_args"
 
 (* Build argument list when p2 >= p1, where p1 is a simple pattern *)
 let rec simple_match_args p1 p2 =

diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "rescript",
-  "version": "12.2.0-rc.1",
+  "version": "12.2.0",
   "description": "ReScript toolchain",
   "type": "module",
   "keywords": [
@@ -10,7 +10,7 @@
     "JavaScript",
     "Language"
   ],
-  "license": "SEE LICENSE IN LICENSE",
+  "license": "(LGPL-3.0-or-later AND MIT)",
   "homepage": "https://rescript-lang.org",
   "bugs": "https://github.com/rescript-lang/rescript/issues",
   "repository": {

diff --git a/packages/@rescript/darwin-arm64/package.json b/packages/@rescript/darwin-arm64/package.json
@@ -1,8 +1,9 @@
 {
   "name": "@rescript/darwin-arm64",
-  "version": "12.2.0-rc.1",
+  "version": "12.2.0",
   "description": "ReScript binaries for MacOS ARM64",
   "type": "module",
+  "license": "(LGPL-3.0-or-later AND MIT)",
   "homepage": "https://rescript-lang.org",
   "bugs": "https://github.com/rescript-lang/rescript/issues",
   "repository": {

diff --git a/packages/@rescript/darwin-x64/package.json b/packages/@rescript/darwin-x64/package.json
@@ -1,8 +1,9 @@
 {
   "name": "@rescript/darwin-x64",
-  "version": "12.2.0-rc.1",
+  "version": "12.2.0",
   "description": "ReScript binaries for MacOS x86_64",
   "type": "module",
+  "license": "(LGPL-3.0-or-later AND MIT)",
   "homepage": "https://rescript-lang.org",
   "bugs": "https://github.com/rescript-lang/rescript/issues",
   "repository": {

diff --git a/packages/@rescript/linux-arm64/package.json b/packages/@rescript/linux-arm64/package.json
@@ -1,8 +1,9 @@
 {
   "name": "@rescript/linux-arm64",
-  "version": "12.2.0-rc.1",
+  "version": "12.2.0",
   "description": "ReScript binaries for Linux ARM64",
   "type": "module",
+  "license": "(LGPL-3.0-or-later AND MIT)",
   "homepage": "https://rescript-lang.org",
   "bugs": "https://github.com/rescript-lang/rescript/issues",
   "repository": {

diff --git a/packages/@rescript/linux-x64/package.json b/packages/@rescript/linux-x64/package.json
@@ -1,8 +1,9 @@
 {
   "name": "@rescript/linux-x64",
-  "version": "12.2.0-rc.1",
+  "version": "12.2.0",
   "description": "ReScript binaries for Linux x86_64",
   "type": "module",
+  "license": "(LGPL-3.0-or-later AND MIT)",
   "homepage": "https://rescript-lang.org",
   "bugs": "https://github.com/rescript-lang/rescript/issues",
   "repository": {

diff --git a/packages/@rescript/runtime/Belt.res b/packages/@rescript/runtime/Belt.res
@@ -1,26 +1,8 @@
 /* Copyright (C) 2015-2016 Bloomberg Finance L.P.
+ * Copyright (C) 2017- Hongbo Zhang, Authors of ReScript
  *
- * 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, either version 3 of the License, or
- * (at your option) any later version.
- *
- * In addition to the permissions granted to you by the LGPL, you may combine
- * or link a "work that uses the Library" with a publicly distributed version
- * of this file to produce a combined library or application, then distribute
- * that combined work under the terms of your choosing, with no requirement
- * to comply with the obligations normally placed on you by section 4 of the
- * LGPL version 3 (or the corresponding section of a later version of the LGPL
- * should you choose to use a 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. */
+ * SPDX-License-Identifier: MIT
+ */
 
 /*** The ReScript standard library.
 

diff --git a/packages/@rescript/runtime/Belt_Array.res b/packages/@rescript/runtime/Belt_Array.res
@@ -1,15 +1,8 @@
-/* ********************************************************************* */
-/*  */
-/* OCaml */
-/*  */
-/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
-/*  */
-/* Copyright 1996 Institut National de Recherche en Informatique et */
-/* en Automatique.  All rights reserved.  This file is distributed */
-/* under the terms of the GNU Library General Public License, with */
-/* the special exception on linking described in file ../LICENSE. */
-/*  */
-/* ********************************************************************* */
+/* Copyright (C) 2015-2016 Bloomberg Finance L.P.
+ * Copyright (C) 2017- Hongbo Zhang, Authors of ReScript
+ *
+ * SPDX-License-Identifier: MIT
+ */
 
 /* Array operations */
 type t<'a> = array<'a>

diff --git a/packages/@rescript/runtime/Belt_Array.resi b/packages/@rescript/runtime/Belt_Array.resi
@@ -1,16 +1,8 @@
-/* ********************************************************************* */
-/*  */
-/* OCaml */
-/*  */
-/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
-/*  */
-/* Copyright 1996 Institut National de Recherche en Informatique et */
-/* en Automatique.  All rights reserved.  This file is distributed */
-/* under the terms of the GNU Library General Public License, with */
-/* the special exception on linking described in file ../LICENSE. */
-/*  */
-/* ********************************************************************* */
-/* Adapted significantly by Authors of ReScript */
+/* Copyright (C) 2015-2016 Bloomberg Finance L.P.
+ * Copyright (C) 2017- Hongbo Zhang, Authors of ReScript
+ *
+ * SPDX-License-Identifier: MIT
+ */
 
 /***
 Utilities for `Array` functions.

diff --git a/packages/@rescript/runtime/Belt_Float.res b/packages/@rescript/runtime/Belt_Float.res
@@ -1,26 +1,8 @@
-/* Copyright (C) 2017 Hongbo Zhang, Authors of ReScript
+/* Copyright (C) 2015-2016 Bloomberg Finance L.P.
+ * Copyright (C) 2017- Hongbo Zhang, Authors of ReScript
  *
- * 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, either version 3 of the License, or
- * (at your option) any later version.
- *
- * In addition to the permissions granted to you by the LGPL, you may combine
- * or link a "work that uses the Library" with a publicly distributed version
- * of this file to produce a combined library or application, then distribute
- * that combined work under the terms of your choosing, with no requirement
- * to comply with the obligations normally placed on you by section 4 of the
- * LGPL version 3 (or the corresponding section of a later version of the LGPL
- * should you choose to use a 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. */
+ * SPDX-License-Identifier: MIT
+ */
 
 /*** [`Belt.Float`]()
     Utilities for Float