From a6ccab92fe218cfe170eb5dadc2c3e898482f573 Mon Sep 17 00:00:00 2001
From: Jeon Yoonjae <yoonjae.jeon@devsisters.com>
Date: Thu, 6 Nov 2025 00:31:34 +0900
Subject: [PATCH] Fix crash in Selectable unapply with custom applyDynamic
 (#24343)

closes: https://github.com/scala/scala3/issues/24168
[Cherry-picked c9c7187ccaa0237d05b82a74338143f07fa6f949]
---
 compiler/src/dotty/tools/dotc/typer/Dynamic.scala |  4 ++--
 tests/neg/i24168.scala                            | 12 ++++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)
 create mode 100644 tests/neg/i24168.scala

diff --git a/compiler/src/dotty/tools/dotc/typer/Dynamic.scala b/compiler/src/dotty/tools/dotc/typer/Dynamic.scala
index 8d48651ad6e9..683244cc8795 100644
--- a/compiler/src/dotty/tools/dotc/typer/Dynamic.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Dynamic.scala
@@ -43,9 +43,9 @@ object DynamicUnapply {
   def unapply(tree: tpd.Tree): Option[List[tpd.Tree]] = tree match
     case TypeApply(Select(qual, name), _) if name == nme.asInstanceOfPM =>
       unapply(qual)
-    case Apply(Apply(Select(selectable, fname), Literal(Constant(name)) :: ctag :: Nil), _ :: implicits)
+    case Apply(Apply(Select(selectable, fname), Literal(Constant(name)) :: restArgs), _ :: implicits)
     if fname == nme.applyDynamic && (name == "unapply" || name == "unapplySeq") =>
-      Some(selectable :: ctag :: implicits)
+      Some(selectable :: (restArgs ::: implicits))
     case _ =>
       None
 }
diff --git a/tests/neg/i24168.scala b/tests/neg/i24168.scala
new file mode 100644
index 000000000000..b554e4d817d5
--- /dev/null
+++ b/tests/neg/i24168.scala
@@ -0,0 +1,12 @@
+trait Generic extends Selectable:
+  def applyDynamic(name: String)(args: Any*): Any = ()
+
+val foo: Generic {
+  def unapply(x: Int): Option[Unit]
+} = new Generic:
+  def unapply(x: Int): Option[Unit] = Some(())
+
+def x =
+  42 match
+    case foo(()) => println("lol") // error
+