Goal:
  
  G : t
  z : V.t
  x : V.t
  y : V.t
  z0 : V.t
  e : EdgeOf x y
  p : PathOf y z0
  q : PathOf z0 z
  IHp : weight (concat p q) = weight p + weight q
  ============================
   (e.π1 + weight (concat p q) = e.π1 + weight p + weight q)


DEBUG:Going to execute:
f x
Level 3: evaluation returns
<coq-core.plugins.tauto::with_uniform_flags@0>
where
f := fun flags => <Coq.Init.Tauto.intuition_gen> flags tac
     where
     tac := idtac; intuition_solver
     of type
     tacvalue
of type
tacvalue of type tacvalue

Level 2: evaluation returns
<coq-core.plugins.tauto::with_uniform_flags@0>
where
f := fun flags => <Coq.Init.Tauto.intuition_gen> flags tac
     where
     tac := idtac; intuition_solver
     of type
     tacvalue
of type
tacvalue of type tacvalue