Comment by rstuart4133

True, but I would have been surprised if that wasn't the case. The reason line looked wrong to me is the lifetime of Some(l) was shorter than the type declaration wanted. The simplest explanation for the bug is compiler wasn't checking the lifetime at all, and the link you provided seems to confirm that is the case.

If that's true it's not a very complex or subtle bug. The very first response of "How on earth was this not found before this???" seems entirely appropriate to me.