From 2fb2ca9ba8d5dde8af0fa57c69c600ca3e64f3e2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Xavier=20R=2E=20Gu=C3=A9rin?=
 <xguerin@users.noreply.github.com>
Date: Mon, 3 Nov 2025 10:39:40 -0500
Subject: [PATCH] Use match variable in mappings to avoid unsed variables

---
 bitstring.opam       |  2 +-
 dune-project         |  4 ++--
 ppx/ppx_bitstring.ml | 20 +++++++++++++-------
 ppx_bitstring.opam   |  4 ++--
 4 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/bitstring.opam b/bitstring.opam
index dce7a4c..18e3b56 100644
--- a/bitstring.opam
+++ b/bitstring.opam
@@ -1,6 +1,6 @@
 # This file is generated by dune, edit dune-project instead
 opam-version: "2.0"
-version: "5.0.1"
+version: "5.0.2"
 synopsis: "Bitstrings and bitstring matching for OCaml"
 description: """
 The ocaml-bitstring project adds Erlang-style bitstrings and matching over bitstrings as a syntax extension and library for OCaml. 
diff --git a/dune-project b/dune-project
index 8906faf..f217853 100644
--- a/dune-project
+++ b/dune-project
@@ -2,7 +2,7 @@
 
 (name bitstring)
 
-(version 5.0.1)
+(version 5.0.2)
 
 (generate_opam_files true)
 
@@ -34,7 +34,7 @@
  )
  (depends
   (ocaml (>= 5.2.0))
-  (bitstring (>= 5.0.1))
+  (bitstring (>= 5.0.2))
   (ocaml (and :with-test (>= 5.2.0)))
   (ppxlib (>= 0.36.0))
   (ounit :with-test)))
diff --git a/ppx/ppx_bitstring.ml b/ppx/ppx_bitstring.ml
index 058ca99..3717b63 100644
--- a/ppx/ppx_bitstring.ml
+++ b/ppx/ppx_bitstring.ml
@@ -18,6 +18,12 @@ open Ppxlib
 open Printf
 open Ast_builder.Default
 
+(* Exception *)
+
+let location_exn ~loc msg =
+  Location.raise_errorf ~loc "%s" msg
+;;
+
 (* Type definition *)
 
 module Entity = struct
@@ -167,13 +173,12 @@ module MatchField = struct
     | Any of Parsetree.pattern
     | Tuple of tuple
   ;;
-end
 
-(* Exception *)
-
-let location_exn ~loc msg =
-  Location.raise_errorf ~loc "%s" msg
-;;
+  let as_evar v = 
+    match v.pat with
+    | {ppat_desc = Ppat_var(v); _} -> evar ~loc:v.loc v.txt
+    | {ppat_loc; _} -> location_exn ~loc:ppat_loc "Pattern is not a variable"
+end
 
 (* Helper functions *)
 
@@ -691,7 +696,8 @@ let gen_value ~loc fld res beh =
   | Some b, None  ->
     [%expr let [%p fld.pat] = [%e b] in [%e beh]][@metaloc loc]
   | None, Some m  ->
-    [%expr let [%p fld.pat] = [%e m] [%e res] in [%e beh]][@metaloc loc]
+    let exp = MatchField.as_evar fld in
+    [%expr let [%p fld.pat] = [%e m] [%e exp] in [%e beh]][@metaloc loc]
   | _, _ -> beh
 ;;
 
diff --git a/ppx_bitstring.opam b/ppx_bitstring.opam
index 0029b79..cf574e5 100644
--- a/ppx_bitstring.opam
+++ b/ppx_bitstring.opam
@@ -1,6 +1,6 @@
 # This file is generated by dune, edit dune-project instead
 opam-version: "2.0"
-version: "5.0.1"
+version: "5.0.2"
 synopsis: "Bitstrings and bitstring matching for OCaml - PPX extension"
 description: """
 The ocaml-bitstring project adds Erlang-style bitstrings and matching over bitstrings as a syntax extension and library for OCaml. 
@@ -15,7 +15,7 @@ bug-reports: "https://github.com/xguerin/bitstring/issues"
 depends: [
   "dune" {>= "2.7"}
   "ocaml" {>= "5.2.0"}
-  "bitstring" {>= "5.0.1"}
+  "bitstring" {>= "5.0.2"}
   "ocaml" {with-test & >= "5.2.0"}
   "ppxlib" {>= "0.36.0"}
   "ounit" {with-test}