Fix #1515: Don't narrow gadt bounds when frozen

Fixes #1515. Review by @smarter.

1 files changed, 16 insertions, 0 deletions

diff --git a/tests/pos/i1515.scala b/tests/pos/i1515.scala
new file mode 100644
index 000000000..fb3ad78ee
--- /dev/null
+++ b/tests/pos/i1515.scala
@@ -0,0 +1,16 @@
+sealed trait Trait[T]
+
+final case class Case[T](e: T) extends Trait[T]
+
+object Demo {
+  def main(args: Array[String]): Unit = {
+
+    def f[H](t: Trait[H]): Unit =
+      t match {
+        case Case(e) => println(Some(e))
+      }
+
+    f(Case(1))
+
+  }
+}