Goal:
  
  hd : A.t
  tl : t
  X : lt_ tl tl
  IHX : let H := CoreTactics.block in
        forall x : t,
        {| pr1 := x; pr2 := x |} = {| pr1 := tl; pr2 := tl |} ->
        let H0 := CoreTactics.block in let H1 := CoreTactics.block in False
  ============================
   (let H := CoreTactics.block in let H0 := CoreTactics.block in False)


DEBUG:Going to execute:
cbv beta