Goal:
    z : t  hd : A.t  tl : list A.t  hd0 : A.t  tl0 : list A.t
  ============================
   ({| pr1 := hd :: tl; pr2 := z |} = {| pr1 := []; pr2 := hd0 :: tl0 |} ->
    let H := CoreTactics.block in let H0 := CoreTactics.block in lt [] z)


DEBUG:Going to execute:
simplify * || simplify ?; cbv beta