From cfab282e97dd66bba93049fbe665dd87c91b2689 Mon Sep 17 00:00:00 2001
From: Yoonjae Jeon <yoonjae.jeon@devsisters.com>
Date: Fri, 19 Sep 2025 17:18:49 +0900
Subject: [PATCH] Call inhabited for AppliedType recursively

---
 .../tools/dotc/transform/patmat/Space.scala    |  1 +
 tests/pos/i23734.scala                         | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 tests/pos/i23734.scala

diff --git a/compiler/src/dotty/tools/dotc/transform/patmat/Space.scala b/compiler/src/dotty/tools/dotc/transform/patmat/Space.scala
index 2baae092a1f3..7857f8c86189 100644
--- a/compiler/src/dotty/tools/dotc/transform/patmat/Space.scala
+++ b/compiler/src/dotty/tools/dotc/transform/patmat/Space.scala
@@ -702,6 +702,7 @@ object SpaceEngine {
             case OrType(tp1, tp2) => inhabited(tp1) || inhabited(tp2)
             case tp: RefinedType => inhabited(tp.parent)
             case tp: TypeRef => !containsUninhabitedField(tp) && inhabited(tp.prefix)
+            case tp: AppliedType => !containsUninhabitedField(tp) && inhabited(tp.tycon)
             case _ => !containsUninhabitedField(tp)
 
           if inhabited(refined) then refined
diff --git a/tests/pos/i23734.scala b/tests/pos/i23734.scala
new file mode 100644
index 000000000000..308bfdae3fa9
--- /dev/null
+++ b/tests/pos/i23734.scala
@@ -0,0 +1,18 @@
+trait Nodes1 {
+  sealed trait B
+  final case class R1() extends B
+}
+
+trait Nodes2 extends Nodes1 {
+  final case class R2[T]() extends B
+}
+
+
+object Impl1 extends Nodes1
+
+object test2 {
+  val a: Impl1.B = ???
+  a match {
+    case Impl1.R1() => ???
+  }
+}