Goal:
    A : Type  B : Type  P : A → B → Type  Q : A → B → Type
  ============================
   ({| pr1 := []; pr2 := [] |} = {| pr1 := []; pr2 := [] |}
    → let H := CoreTactics.block in
      let H0 := CoreTactics.block in All2 (Trel_conj P Q) [] [])


DEBUG:Going to execute:
simplify * || simplify ?