@tailrec not properly enforced

[allanrenucci]

class Test {
  def cond: Boolean = ???
  def foo(x: => Int) = ???

  @annotation.tailrec
  final def bar: Int =
    if (cond) foo(bar) // should be an error
    else bar
}

t4649 is a pending test case

[odersky]

What is tail recursion? I'd argue this is not a violation of it. What we have is really analogous to

class Test {
  def cond: Boolean = ???
  def foo(x: Test) = x.bar

  @annotation.tailrec
  final def bar: Int =
    if (cond) foo(this) 
    else bar
}

and that one is regarded as tailrecursive as well.

[allanrenucci]

We decided to report @tailrec failure within local methods as well.

It should cover this example, since by-name expends to closures which expends to local methods