Merge pull request #1507 from retronym/ticket/6526

SI-6526 Tail call elimination should descend deeper.

2 files changed, 57 insertions, 0 deletions

diff --git a/test/files/neg/t6526.check b/test/files/neg/t6526.check
new file mode 100644
index 0000000000..606c18c301
--- /dev/null
+++ b/test/files/neg/t6526.check
@@ -0,0 +1,16 @@
+t6526.scala:8: error: could not optimize @tailrec annotated method inner: it contains a recursive call not in tail position
+    @tailrec def inner(i: Int): Int = 1 + inner(i)
+                                        ^
+t6526.scala:14: error: could not optimize @tailrec annotated method inner: it contains a recursive call not in tail position
+    @tailrec def inner(i: Int): Int = 1 + inner(i)
+                                        ^
+t6526.scala:20: error: could not optimize @tailrec annotated method inner: it contains a recursive call not in tail position
+    @tailrec def inner(i: Int): Int = 1 + inner(i)
+                                        ^
+t6526.scala:30: error: could not optimize @tailrec annotated method inner: it contains a recursive call not in tail position
+        @tailrec def inner(i: Int): Int = 1 + inner(i)
+                                            ^
+t6526.scala:39: error: could not optimize @tailrec annotated method inner: it contains a recursive call not in tail position
+    def inner(i: Int): Int = 1 + inner(i)
+                               ^
+5 errors found
diff --git a/test/files/neg/t6526.scala b/test/files/neg/t6526.scala
new file mode 100644
index 0000000000..0bc249aa98
--- /dev/null
+++ b/test/files/neg/t6526.scala
@@ -0,0 +1,41 @@
+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
+    }
+  }
+
+  Some(new AnyRef) map { phooie =>
+    @tailrec
+    def inner(i: Int): Int = 1 + inner(i)
+  } getOrElse 42
+}