Goal:
  
  G : t
  idx0 : VSet.t
  idx1 : V.t
  idx : V.t
  a : SPath idx0 idx1 idx
  b : sigma
        (fun index : sigma (fun _ : VSet.t => sigma (fun _ : V.t => V.t)) =>
         SPath (pr1 index) (pr1 (pr2 index)) (pr2 (pr2 index)))
  e : NoConfusion_SPath
        {|
          pr1 := {| pr1 := idx0; pr2 := {| pr1 := idx1; pr2 := idx |} |};
          pr2 := a
        |} b
  ============================
   (noConfusion_SPath_obligation_2
      {|
        pr1 := {| pr1 := idx0; pr2 := {| pr1 := idx1; pr2 := idx |} |};
        pr2 := a
      |} b
      (noConfusion_SPath_obligation_1
         {|
           pr1 := {| pr1 := idx0; pr2 := {| pr1 := idx1; pr2 := idx |} |};
           pr2 := a
         |} b e) = e)


DEBUG:Going to execute:
let idx := fresh "idx" in
           destruct id as [idx id]; repeat CoreTactics.destruct_sigma idx;
            simpl in id
DEBUG LTAC Evaluated term: b
DEBUG LTAC Evaluated term: (sigma
                              (fun
                                 index : sigma
                                           (fun _ : VSet.t =>
                                            sigma (fun _ : V.t => V.t)) =>
                               SPath (pr1 index) (pr1 (pr2 index))
                                 (pr2 (pr2 index))))
Level 4: type of id
 has value 
(sigma
   (fun index : sigma (fun _ : VSet.t => sigma (fun _ : V.t => V.t)) =>
    SPath (pr1 index) (pr1 (pr2 index)) (pr2 (pr2 index))))