Goal:
  
  A : Type
  B : Type
  C : Type
  P : nat → A → B → Type
  Q : B → C → Type
  R : nat → A → C → Type
  S : nat → A → C → Type
  y0 : C
  l' : list C
  n : nat
  x : A
  y : B
  l : list A
  r : list B
  r0 : P n x y
  a : All2i P (Datatypes.S n) l r
  q : Q y y0
  b : All2 Q r l'
  c : All2i R n (x :: l) (y0 :: l')
  ============================
   (let H := CoreTactics.block in
    (∀ (n : nat) (x : A) (y : B) (z : C), P n x y → Q y z → R n x z → S n x z)
    → (∀ l'' : list C,
         All2 Q r l''
         → All2i R (Datatypes.S n) l l'' → All2i S (Datatypes.S n) l l'')
      → let H0 := CoreTactics.block in All2i S n (x :: l) (y0 :: l'))


DEBUG:Going to execute:
DepElim.generalize_by_eqs H
Level 0: Backtrace:

Failed to progress.
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Failed to progress.
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Failed to progress.
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Failed to progress.
Level 0: Backtrace:

Failed to progress.