Fix #10549: Add test

Author: liufengyun

tests/init/neg/i10549b.scala

@@ -0,0 +1,9 @@
+class Wrap {
+  def qux[T](e: E[T]) = e.foo
+
+  abstract class E[+T] { def foo: T }
+  object E {
+    final val A: E[Nothing] = new E { def foo = ref }
+    val ref = qux(A)      // error
+  }
+}

tests/init/pos/i10549a.scala

@@ -0,0 +1,7 @@
+class Wrap {
+  class E
+  object E {
+    final val A = new E {}
+    val $values = Array(A)
+  }
+}