Goal:
  
  G : t
  invG : invariants G
  acG : acyclic_no_loop' G
  x : V.t
  s : VSet.t
  p : SPath G s x x
  wp : sweight p > 0
  ============================
   (weight (to_pathOf G p) > 0)


DEBUG:Going to execute:
<coq-core.plugins.ssreflect::ssrrewrite@0> $1 $2