open tactic

meta_definition rewriteH (Hname : name) : tactic unit :=
do get_local Hname >>= rewrite_core reducible tt occurrences.all ff,
   try reflexivity

example (l : list nat) : list.append l [] = l :=
by do
  get_local "l" >>= λ H, induction_core semireducible H ("list" <.> "rec_on") ["h", "t", "iH"],
  --
  unfold ["list" <.> "append"],
  trace_state,
  trace "------",
  reflexivity,
  unfold ["list" <.> "append"],
  trace_state,
  rewriteH "iH"