Goal:
  
  G : t
  HI : invariants G
  HG : acyclic_no_loop G
  x : V.t
  z : Z
  p : SPath G (V G) x (s G)
  p0 : sigma
         (fun index : sigma (fun _ : VSet.t => sigma (fun _ : V.t => V.t)) =>
          SPath G (pr1 index) (pr1 (pr2 index)) (pr2 (pr2 index)))
  ============================
   ({|
      pr1 := {| pr1 := V G; pr2 := {| pr1 := x; pr2 := s G |} |}; pr2 := p
    |} = p0 ->
    let H := CoreTactics.block in
    sweight p = z ->
    ~ VSet.In x (V G) -> let H0 := CoreTactics.block in z = 0)


DEBUG:Going to execute:
move_after_deps id' t; CoreTactics.revert_until id'; rename
            id' into id
Level 2: evaluation returns
move_after_deps id' t; CoreTactics.revert_until id'; rename id' into id;
 cont id'1 id
where
t := {|
       pr1 := {| pr1 := V G; pr2 := {| pr1 := x; pr2 := s G |} |}; pr2 := p
     |}
of type
constr
id'1 := p
of type
constr
id' := p0
of type
constr
id := p
of type
constr
cont := fun id id' => DepElim.decompose_exists id id'
        where
        id := p
        of type
        constr
of type
tacvalue of type tacvalue