Goal:
  
  A : Type
  B : Type
  C : Type
  Q : C → Type
  R : C → A → Prop
  f : ∀ x : A, (∀ y : C, Q y → R y x) → B
  x : A
  xs : list A
  h : ∀ y : C, Q y → ∥ All (R y) (x :: xs) ∥
  X : ∀ (H := CoreTactics.block) (P : C → A → Prop) 
        (Q' : B → Type) (args : list A) (ha : ∀ y : C,
                                                Q y → ∥ All (R y) args ∥),
        {| pr1 := xs; pr2 := map_All_obligation_2 x xs h |} =
        {| pr1 := args; pr2 := ha |}
        → map_All f xs (map_All_obligation_2 x xs h) = map_All f args ha
          → let H0 := CoreTactics.block in
            (∀ y : C, Q y → All (P y) args)
            → (∀ (x : A) (y : C) (rx : ∀ y0 : C, Q y0 → R y0 x),
                 P y x → Q' (f x rx))
              → ∀ y : C, Q y → All Q' (map_All f args ha)
  P : C → A → Prop
  Q' : B → Type
  ============================
   (let H := CoreTactics.block in
    (∀ y : C, Q y → All (P y) (x :: xs))
    → (∀ (x : A) (y : C) (rx : ∀ y0 : C, Q y0 → R y0 x), P y x → Q' (f x rx))
      → ∀ y : C, Q y → All Q' (map_All f (x :: xs) h))


DEBUG:Going to execute:
match goal with
           | hyp:context [ CoreTactics.block ]
             |- _ =>
                 cbn beta in hyp; eqns_specialize_eqs_block hyp;
                  cbn[eq_rect_r eq_rect] in hyp
           end
Level 1: Backtrace:

No matching clauses for match.