1 files changed, 36 insertions, 0 deletions
diff --git a/test/pos/IntSet.scala b/test/pos/IntSet.scala
new file mode 100644
index 0000000000..850a5cb923
--- /dev/null
+++ b/test/pos/IntSet.scala
@@ -0,0 +1,36 @@
+trait IntSet {
+  def incl(x: Int): IntSet;
+  def contains(x: Int): Boolean;
+  def foreach(f: Int => Unit): Unit;
+  def union(that: IntSet): IntSet;
+}
+module Empty extends IntSet {
+  def contains(x: Int): Boolean = Boolean.False;
+  def incl(x: Int): IntSet = new NonEmpty(x, Empty, Empty);
+  def foreach(f: Int => Unit): Unit = ();
+  def union(that: IntSet): IntSet = that;
+}
+class NonEmpty(elem: Int, left: IntSet, right: IntSet) extends IntSet {
+  def contains(x: Int): Boolean =
+    if (x < elem) left contains x
+    else if (x > elem) right contains x
+    else True;
+  def incl(x: Int): IntSet =
+    if (x < elem) new NonEmpty(elem, left incl x, right)
+    else if (x > elem) new NonEmpty(elem, left, right incl x)
+    else this;
+  def foreach(f: Int => Unit): Unit = {
+    left foreach f;
+    f(elem);
+    right foreach f;
+  }
+  def union(that: IntSet): IntSet = (left union (right union that)) incl elem;
+}
+module test {
+  def main = {
+    val x = Empty incl 1 incl 2;
+    val y = Empty incl 2 incl 3;
+    x foreach java.lang.System.out.println;
+    y foreach java.lang.System.out.println;
+  }
+}
+\ No newline at end of file