SI-8893 Test case to show that tailrec continues to work

As suggested during code review, this test checks that
the tailcalls phase recurses appropriately below a method
that doesn and does not itself tail call. The test case is
based on the pattern of code that to trigger super-linear
performance in this transform.

1 files changed, 40 insertions, 0 deletions

diff --git a/test/files/run/t8893.scala b/test/files/run/t8893.scala
new file mode 100644
index 0000000000..6fef8ae912
--- /dev/null
+++ b/test/files/run/t8893.scala
@@ -0,0 +1,40 @@
+import annotation.tailrec
+
+object Test {
+  def a(): Option[String] = Some("a")
+
+  def test1: Any = {
+    a() match {
+      case Some(b1) =>
+        a() match {
+          case Some(b2) =>
+            @tailrec
+            def tick(i: Int): Unit = if (i < 0) () else tick(i - 1)
+            tick(10000000) // testing that this doesn't SOE
+          case None => None
+        }
+      case None => None
+    }
+  }
+
+  def test2: Any = {
+    a() match {
+      case Some(b1) =>
+        a() match {
+          case Some(b2) =>
+            @tailrec
+            def tick(i: Int): Unit = if (i < 0) () else tick(i - 1)
+            tick(10000000) // testing that this doesn't SOE
+          case None => test1
+        }
+      case None =>
+        test1 // not a tail call
+        test1
+    }
+  }
+
+  def main(args: Array[String]) {
+    test1
+    test2
+  }
+}