SI-9110 Pattern `O.C` must check `$outer eq O` for a top level O

The outer check was not being generated when the prefix was a
top level module. The enclosed test shows that we in fact must
synthesize the outer check in that case.

Perhaps the bug was introduced by neglecting to consider that
a module can inherit member classes.

1 files changed, 27 insertions, 0 deletions

diff --git a/test/files/run/t9110.scala b/test/files/run/t9110.scala
new file mode 100644
index 0000000000..660291a4d1
--- /dev/null
+++ b/test/files/run/t9110.scala
@@ -0,0 +1,27 @@
+trait Event
+
+trait Domain {
+  case class Created(name: String) extends Event
+}
+
+// declare three instances of Domain trait, one here and two
+// in an inner scope
+
+object DomainC extends Domain
+
+object Test {
+ def main(args: Array[String]) {
+   object DomainA extends Domain
+   object DomainB extends Domain
+
+   def lookingForAs(event: Event): Unit = {
+      event match {
+        case DomainB.Created(_) => throw null
+        case DomainC.Created(_) => throw null
+        case DomainA.Created(_) => // okay
+      }
+   }
+
+   lookingForAs(DomainA.Created("I am an A"))
+  }
+}