fix CI

Author: liufengyun

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

@@ -299,7 +299,10 @@ class SpaceEngine(implicit ctx: Context) extends SpaceLogic {
 
     debug.println(s"atomic intersection: ${and.show} = ${res}")
 
-    if (res) Typ(and, true) else Empty
+    if (!res) Empty
+    else if (tp1.isSingleton) Typ(tp1, true)
+    else if (tp2.isSingleton) Typ(tp2, true)
+    else Typ(and, true)
   }
 
   /** Whether the extractor is irrefutable */

tests/patmat/file.scala

@@ -0,0 +1,15 @@
+abstract class AbstractFile
+class PlainFile(path: String) extends AbstractFile
+class VirtualFile(name: String) extends AbstractFile
+abstract class ZipArchive(path: String) extends AbstractFile {
+  sealed abstract class Entry(name: String) extends VirtualFile(name)
+  class DirEntry(path: String) extends Entry(path)
+}
+
+object Test {
+  def foo(file: AbstractFile) =  file match {
+    case ze: ZipArchive#Entry =>
+    case pf: PlainFile =>
+    case _ =>
+  }
+}