Add test

Author: liufengyun

tests/init/neg/t92661.scala

@@ -0,0 +1,3 @@
+sealed abstract class OrderType(val reverse: OrderType)
+case object Buy extends OrderType(Sell)       // error
+case object Sell extends OrderType(Buy)       // error

tests/init/neg/t9312.scala

@@ -0,0 +1,23 @@
+object DeadLockTest {
+  def main(args: Array[String]): Unit = {
+    def run(block: => Unit): Unit =
+      new Thread(new Runnable {def run(): Unit = block}).start()
+
+    run {println(Parent.Child1)}
+    run {println(Parent.Child2)}
+
+  }
+
+  object Parent {    // error
+    trait Child {
+      Thread.sleep(2000) // ensure concurrent behavior
+      val parent = Parent
+      def siblings = parent.children - this
+    }
+
+    object Child1 extends Child     // error
+    object Child2 extends Child     // error
+
+    final val children = Set(Child1, Child2)  // error
+  }
+}