Add tests

Author: liufengyun

tests/pos/i6849a.scala

@@ -0,0 +1,14 @@
+final class Foo(val value: Int)
+
+object Foo {
+  def unapplySeq(foo: Foo): Seq[Int] = List(foo.value)
+}
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    (new Foo(3)) match {
+      case Foo(x, _: _*) =>
+        assert(x == 3)
+    }
+  }
+}

tests/pos/i6849b.scala

@@ -0,0 +1,5 @@
+object A {
+  def unapplySeq(a: Any): Seq[_] = ""
+}
+
+def unapply(x: Any) = x match { case A() => }