From fe3f90bf29d96e8e92ae87572a74afb46fe17dec Mon Sep 17 00:00:00 2001
From: Albert Meltzer <7529386+kitbellew@users.noreply.github.com>
Date: Wed, 18 Oct 2023 08:36:00 -0700
Subject: [PATCH 1/2] Add test with trailing commas in tuple

---
 .../trailingCommasAlwaysSingleLine.stat                |  9 +++++++++
 .../trailing-commas/trailingCommasNeverSingleLine.stat |  9 +++++++++
 .../trailing-commas/trailingCommasPreserve.stat        | 10 ++++++++++
 3 files changed, 28 insertions(+)

diff --git a/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasAlwaysSingleLine.stat b/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasAlwaysSingleLine.stat
index 411a08f455..dc72a029ea 100644
--- a/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasAlwaysSingleLine.stat
+++ b/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasAlwaysSingleLine.stat
@@ -15,3 +15,12 @@ foo(
 )
 >>>
 foo(a)
+<<< #3663 tuple
+val x = (
+  "a", 
+  "b",
+)
+>>>
+test does not parse
+val x = ("a", "b", )
+                   ^
diff --git a/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasNeverSingleLine.stat b/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasNeverSingleLine.stat
index 84b2afdb2f..fc513cc222 100644
--- a/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasNeverSingleLine.stat
+++ b/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasNeverSingleLine.stat
@@ -15,3 +15,12 @@ foo(
 )
 >>>
 foo(a)
+<<< #3663 tuple
+val x = (
+  "a", 
+  "b",
+)
+>>>
+test does not parse
+val x = ("a", "b", )
+                   ^
diff --git a/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasPreserve.stat b/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasPreserve.stat
index 84ef63c66f..1f2699f20c 100644
--- a/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasPreserve.stat
+++ b/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasPreserve.stat
@@ -353,3 +353,13 @@ object a {
       b: Int /* c */
   ) = a + b
 }
+<<< #3663 tuple
+val x = (
+  "a", 
+  "b",
+)
+>>>
+val x = (
+  "a",
+  "b",
+)

From 275b2fbe6365925a59e4099673a7cdcf4f7cbd8a Mon Sep 17 00:00:00 2001
From: Albert Meltzer <7529386+kitbellew@users.noreply.github.com>
Date: Wed, 18 Oct 2023 08:46:27 -0700
Subject: [PATCH 2/2] RewriteTrailingCommas: allow tuples as well

---
 .../scala/org/scalafmt/rewrite/RewriteTrailingCommas.scala   | 5 ++++-
 .../trailing-commas/trailingCommasAlwaysSingleLine.stat      | 4 +---
 .../trailing-commas/trailingCommasNeverSingleLine.stat       | 4 +---
 3 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/RewriteTrailingCommas.scala b/scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/RewriteTrailingCommas.scala
index 96cdc98463..9ed755ebb5 100644
--- a/scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/RewriteTrailingCommas.scala
+++ b/scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/RewriteTrailingCommas.scala
@@ -42,7 +42,10 @@ private class RewriteTrailingCommas(ftoks: FormatTokens)
 
       // comma and paren/bracket/brace need to have the same owner
       (rightOwner eq nft.meta.rightOwner) && (nft.right match {
-        case _: Token.RightBracket | _: Token.RightParen =>
+        case _: Token.RightParen =>
+          rightOwner.isAny[Member.SyntaxValuesClause, Member.Tuple]
+
+        case _: Token.RightBracket =>
           rightOwner.is[Member.SyntaxValuesClause]
 
         case _: Token.RightBrace =>
diff --git a/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasAlwaysSingleLine.stat b/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasAlwaysSingleLine.stat
index dc72a029ea..c2f4e75fd2 100644
--- a/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasAlwaysSingleLine.stat
+++ b/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasAlwaysSingleLine.stat
@@ -21,6 +21,4 @@ val x = (
   "b",
 )
 >>>
-test does not parse
-val x = ("a", "b", )
-                   ^
+val x = ("a", "b")
diff --git a/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasNeverSingleLine.stat b/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasNeverSingleLine.stat
index fc513cc222..09f7662c9c 100644
--- a/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasNeverSingleLine.stat
+++ b/scalafmt-tests/src/test/resources/trailing-commas/trailingCommasNeverSingleLine.stat
@@ -21,6 +21,4 @@ val x = (
   "b",
 )
 >>>
-test does not parse
-val x = ("a", "b", )
-                   ^
+val x = ("a", "b")