extensionality rho; unfold local, lift1; simpl.
apply pred_ext; normalize.7 at level 0, x8 at level 0, x9 at level 0,
              x10 at level 0, x11 at level 0, x12 at level 0, x13 at level 0, x14 at level 0,
              x15 at level 0, x16 at level 0, x17 at level 0, x18 at level 0, x19 at level 0,
              x20 at level 0, x21 at level 0, x22 at level 0,
             P at level 100, Q at level 100).


Notation "'WITH'  x1 : t1 , x2 : t2 , x3 : t3 , x4 : t4 , x5 : t5 , x6 : t6 , x7 : t7 , x8 : t8 , x9 : t9 , x10 : t10 , x11 : t11 , x12 : t12 , x13 : t13 , x14 : t14 , x15 : t15 , x16 : t16 , x17 : t17 , x18 : t18 , x19 : t19 , x20 : t20 , x21 : t21 , x22 : t22 'PRE'  [ u , .. , v ] P 'POST' [ tz ] Q" :=
     (NDmk_funspec ((cons u%formals .. (cons v%formals nil) ..), tz) cc_default (t1*t2*t3*t4*t5*t6*t7*t8*t9*t10*t11*t12*t13*t14*t15*t16*t17*t18*t19*t20*t21*t22)
           (fun x => match x with (x1,x2,x3,x4,x5,x6,x7,x8,x9,x10,x11,x12,x13,x14,x15,x16,x17,x18,x19,x20,x21,x22) => P%assert end)
           (fun x => match x with (x1,x2,x3,x4,x5,x6,x7,x8,x9,x10,x11,x12,x13,x14,x15,x16,x17,x18,x19,x20,x21,x22) => Q%assert end))
            (at level 200, x1 at level 0, x2 at level 0, x3 at level 0, x4 at level 0,
             x5 at level 0, x6 at level 0, x7nt, s: funspec)
   (at level 160, x at level 0, s at level 150, only parsing).

Notation " a 'OF' ta " := (a%positive,ta%type) (at level 100, only parsing): formals.
Delimit Scope formals with formals.

Qed. Hint Rewrite prop_true_andp1 using s