From ded2d065609e4c35d33ef05dd8885c40294d3158 Mon Sep 17 00:00:00 2001
From: Shulhi Sapli <shulhi@gmail.com>
Date: Sun, 8 Sep 2024 15:18:54 +0800
Subject: [PATCH] Fix tuple coercion (#7024)

* Fix tuple coercion

It was only handled for the first arg in the tuple

* Update CHANGELOG
---
 CHANGELOG.md                                           |  3 +++
 jscomp/syntax/src/res_core.ml                          |  1 +
 .../tests/parsing/grammar/expressions/coerce.res       | 10 +++++++++-
 .../grammar/expressions/expected/coerce.res.txt        |  6 +++++-
 4 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 415ff1ad5b..f03c0cdc93 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,9 @@
 
 # 12.0.0-alpha.4 (Unreleased)
 
+#### :bug: Bug fix
+- Fix tuple coercion. https://github.com/rescript-lang/rescript-compiler/pull/7024
+
 # 12.0.0-alpha.3
 
 #### :bug: Bug fix
diff --git a/jscomp/syntax/src/res_core.ml b/jscomp/syntax/src/res_core.ml
index ba182675f7..2e0ee3e902 100644
--- a/jscomp/syntax/src/res_core.ml
+++ b/jscomp/syntax/src/res_core.ml
@@ -1823,6 +1823,7 @@ and parse_constrained_expr_region p =
   | token when Grammar.is_expr_start token -> (
     let expr = parse_expr p in
     match p.Parser.token with
+    | ColonGreaterThan -> Some (parse_coerced_expr ~expr p)
     | Colon ->
       Parser.next p;
       let typ = parse_typ_expr p in
diff --git a/jscomp/syntax/tests/parsing/grammar/expressions/coerce.res b/jscomp/syntax/tests/parsing/grammar/expressions/coerce.res
index e9f73bbf27..f2bd210eff 100644
--- a/jscomp/syntax/tests/parsing/grammar/expressions/coerce.res
+++ b/jscomp/syntax/tests/parsing/grammar/expressions/coerce.res
@@ -1,3 +1,11 @@
 let foo = (x:int) => (x :> int)
 
-let foo = x => (x : t :> int)
\ No newline at end of file
+let foo = x => (x : t :> int)
+
+let _ = (x : int)
+
+let foo = (x : int, y :> float)
+
+let foo = (x : int, y :> float, z :> int)
+
+let foo = (x : int, y, z :> int)
diff --git a/jscomp/syntax/tests/parsing/grammar/expressions/expected/coerce.res.txt b/jscomp/syntax/tests/parsing/grammar/expressions/expected/coerce.res.txt
index 8ad27dde31..1fdea49ce8 100644
--- a/jscomp/syntax/tests/parsing/grammar/expressions/expected/coerce.res.txt
+++ b/jscomp/syntax/tests/parsing/grammar/expressions/expected/coerce.res.txt
@@ -1,2 +1,6 @@
 let foo = ((Function$ (fun (x : int) -> (x :> int)))[@res.arity 1])
-let foo = ((Function$ (fun x -> ((x : t) :> int)))[@res.arity 1])
\ No newline at end of file
+let foo = ((Function$ (fun x -> ((x : t) :> int)))[@res.arity 1])
+let _ = (x : int)
+let foo = ((x : int), (y :> float))
+let foo = ((x : int), (y :> float), (z :> int))
+let foo = ((x : int), y, (z :> int))