SI-6526 Tail call elimination should descend deeper.

It wasn't traversing into Select nodes nor into the receiver of
a tail call.

1 files changed, 36 insertions, 0 deletions

diff --git a/test/files/neg/t6526.scala b/test/files/neg/t6526.scala
new file mode 100644
index 0000000000..a34ba570d0
--- /dev/null
+++ b/test/files/neg/t6526.scala
@@ -0,0 +1,36 @@
+import scala.annotation.tailrec
+
+class TailRec {
+  def bar(f: => Any) = ""
+
+  // transform the qualifier of a Select
+  bar {
+    @tailrec def inner(i: Int): Int = 1 + inner(i)
+    inner(0)
+  }.length
+
+  // transform the body of a function
+  () => {
+    @tailrec def inner(i: Int): Int = 1 + inner(i)
+    inner(0)
+  }
+
+  // transform the qualifier of a Select
+  {
+    @tailrec def inner(i: Int): Int = 1 + inner(i)
+    inner(0)
+    ""
+  }.length
+
+  // The receiver of a tail recursive call must itself be transformed
+  object X {
+    @tailrec // okay, all other annotated methods should fail.
+    def foo: Any = {
+      {
+        @tailrec def inner(i: Int): Int = 1 + inner(i)
+        inner(0)
+        this
+      }.foo
+    }
+  }
+}