Imagine the following code:
(let lp ([items '(1 2 3 4 5)])
(match items
[(list head rest ...)
(cons (* head 2)
(lp rest))]))
My gut feeling is "oh, this is just O(n) because it's pulling the top
off the list.... quite efficient."
But then I realized that:
(match '(1 2 3 4 . 5)
[(list head rest ...)
(* head 2)])
throws an exception because it's a dotted list.
But the documentation says that the `list?` predicate is O(n). I'm
suddenly fearing, have I been writing O(n^2) code this whole time? Does
match against list actually check the whole list every time?
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