Goal:
  
  A : Type
  B : Type
  k : nat
  Q : nat → A → Type
  R : nat → A → B → Type
  l : list A
  l' : list B
  n : nat
  q1 : sigma (λ _ : nat, list A)
  q : Alli Q (pr1 q1) (pr2 q1)
  ============================
   ({| pr1 := n; pr2 := [] |} = q1
    → let H := CoreTactics.block in
      let H0 := CoreTactics.block in
      All2i (λ (i : nat) (x : A) (y : B), Q i x × R i x y) n [] [])


DEBUG:Going to execute:
try rename id into id',id' into id
Level 3: evaluation returns
try rename id into id',id' into id; cont id'1 id
where
t := {| pr1 := n; pr2 := [] |}
of type
constr
id'1 := q1
of type
constr
id' := q
of type
intropattern
id := q
of type
intropattern
cont := fun id id' => DepElim.decompose_exists id id'
        where
        id := q
        of type
        intropattern
of type
tacvalue of type tacvalue