Fix #209: Add regression test

Author: nicolasstucki

tests/run/i209.scala

@@ -0,0 +1,23 @@
+case class Foo(a: Int) {
+  def copy(i: Int = 9): Foo = Foo(i)
+}
+
+case class Bar(a: Int, b: Int) {
+  def copy(i: Int = 4, j: Int = 6): Bar = Bar(i, j)
+}
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val a = Foo(2)
+    assert(a == Foo(2))
+    assert(a.copy(5) == Foo(5))
+    assert(a.copy() == Foo(9))
+
+    val b = Bar(2, 3)
+    assert(b == Bar(2, 3))
+    assert(b.copy(5, 7) == Bar(5, 7))
+    assert(b.copy(5) == Bar(5, 6))
+    assert(b.copy(j = 5) == Bar(4, 5))
+    assert(b.copy() == Bar(4, 6))
+  }
+}