Goal:
  
  A : Type
  m1 : tree' A
  m2 : tree' A
  p : positive
  H : get' p m1 <> None
  IHm2 : exists i : positive, get' i m2 <> None
  ============================
   (get' (xO p) (Node101 m1 m2) <> None)


DEBUG:Going to execute:
<coq-core.plugins.ltac::auto@0> $1 $2 $3