fails:Enumerator#each_cons walks Enumerable elements strictly in forward direction, in parallel with iteration
fails:Enumerator#each_cons allows Enumerable to change during the iteration
fails:"Enumerator#each_cons walks Enumerable elements strictly in forward direction, in parallel with iteration"
fails:"Enumerator#each_cons allows Enumerable to change during the iteration"
fails:Enumerator#each_cons raises LocalJumpError if no block is given
