GADT test

This one failed in getters before because a (previously unchecked) assignment
was turned into a checked application. Now it passes.

1 files changed, 25 insertions, 0 deletions

diff --git a/tests/pos/gadts2.scala b/tests/pos/gadts2.scala
new file mode 100644
index 000000000..71089c0f7
--- /dev/null
+++ b/tests/pos/gadts2.scala
@@ -0,0 +1,25 @@
+object Test {
+
+  abstract class Number
+  case class MyInt(n: Int) extends Number
+  case class MyDouble(d: Double) extends Number
+
+  trait Term[a]
+  case class Cell[a](var x: a) extends Term[a]
+  final case class NumTerm(val n: Number) extends Term[Number]
+
+  def f[A](t: Term[A], c: Cell[A]): Unit = {
+    t match {
+      case NumTerm(n) => c.x = MyDouble(1.0)  // problem is: this assignment is not type correct, since gadt variable is forgotten
+    }
+  }
+
+  val x: Term[Number] = NumTerm(MyInt(5))
+
+  def main(args: Array[String]): Unit = {
+    val cell = Cell[Number](MyInt(6))
+    Console.println(cell)
+    f[Number](new NumTerm(MyInt(5)), cell)
+    Console.println(cell)
+  }
+}