Fix i321, tail call needs to be careful with abstracting over class type arguments.

Or it could lead to Ycheck error that was triggered in #321.

1 files changed, 10 insertions, 0 deletions

diff --git a/tests/pos/tailcall/i321.scala b/tests/pos/tailcall/i321.scala
new file mode 100644
index 000000000..0d32dd625
--- /dev/null
+++ b/tests/pos/tailcall/i321.scala
@@ -0,0 +1,10 @@
+class i321[T >: Null <: AnyRef] {
+
+  def mapconserve(f: T => Int): Int = {
+    def loop(pending: T): Int = {
+        val head1 = f(pending)
+        loop(pending)
+      }
+    loop(null)
+  }
+}
\ No newline at end of file