Goal:
  
  A : Type
  B : Type
  t' : A
  P : B → A → A → Type
  b : B
  bs : list B
  hd : A
  tl : list A
  p : P b hd t'
  e : #|bs| = #|tl|
  ============================
   (P b hd t')


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

Goals:

DEBUG:Going to execute:
repeat (do_intro; try do_atom)

Goals:

DEBUG:Going to execute:
try arith_congr

Goals:

DEBUG:Going to execute:
solve [ split; do_ccl ]