Goal:
  
  A : Type
  B : Type
  R : A → B → Type
  R' : ∀ (a : A) (b : B), R a b → Type
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in All2_dep_nil = All2_dep_nil)


DEBUG:Going to execute:
change T; CoreTactics.intros_until_block
Level 7: T
 has value 
(let H := CoreTactics.block in All2_dep_nil = All2_dep_nil)