Goal:
  
  hd : A.t
  tl : list A.t
  hd' : A.t
  tl' : list A.t
  H : A.lt hd hd'
  x : t
  ============================
   ({| pr1 := x; pr2 := x |} = {| pr1 := hd :: tl; pr2 := hd' :: tl' |} ->
    let H := CoreTactics.block in let H0 := CoreTactics.block in False)


DEBUG:Going to execute:
simplify * || simplify ?