Goal:
  
  A : Type
  P : list A → A → Type
  x : A
  d : A
  Γ : list A
  a : All_fold P Γ
  p : P Γ d
  ============================
   ([x] = d :: Γ
    → let H := CoreTactics.block in let H0 := CoreTactics.block in P [] x)


DEBUG:Going to execute:
simplify * || simplify ?; cbv beta