Merge pull request #608 from scala/backport-lts-3.3-23964

Backport "Call inhabited for AppliedType recursively" to 3.3 LTS

Author: tgodzik

compiler/src/dotty/tools/dotc/transform/patmat/Space.scala

@@ -680,6 +680,7 @@ 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

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() => ???
+  }
+}