Goal:
    A : Type  l : list A  n : nat
  ============================
   (firstn n (firstn (S n) l) = firstn n l)


DEBUG:Going to execute:
induction l in n |- *

Goals:
    A : Type  n : nat
  ============================
   (firstn n (firstn (S n) []) = firstn n [])

  
  A : Type
  a : A
  l : list A
  n : nat
  IHl : ∀ n : nat, firstn n (firstn (S n) l) = firstn n l
  ============================
   (firstn n (firstn (S n) (a :: l)) = firstn n (a :: l))


DEBUG:Going to execute:
simpl
DEBUG LTAC Evaluated term: l

Goals:
    A : Type  n : nat
  ============================
   (firstn n [] = firstn n [])

  
  A : Type
  a : A
  l : list A
  n : nat
  IHl : ∀ n : nat, firstn n (firstn (S n) l) = firstn n l
  ============================
   (firstn n (a :: firstn n l) = firstn n (a :: l))


DEBUG:Going to execute:
auto

Goals:
    A : Type  n : nat
  ============================
   (firstn n [] = firstn n [])

  
  A : Type
  a : A
  l : list A
  n : nat
  IHl : ∀ n : nat, firstn n (firstn (S n) l) = firstn n l
  ============================
   (firstn n (a :: firstn n l) = firstn n (a :: l))


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