Goal:
  
  A : Type
  P : A → Prop
  a : A
  l : list A
  l' : list A
  IHl : Forall P (l ++ l') → Forall P l ∧ Forall P l'
  H0 : P a
  H1 : Forall P (l ++ l')
  ============================
   (Forall P (a :: l) ∧ Forall P l')


DEBUG:Going to execute:
split
Level 0: Backtrace:

In environment
A : Type
P : A → Prop
l' : list A
H : Forall P ([] ++ l')
Unable to unify "Forall ?M2741 (?M2742 :: ?M2743)" with 
"Forall P l'".
Level 0: Backtrace:

In environment
A : Type
P : A → Prop
l' : list A
H : Forall P ([] ++ l')
Unable to unify "Forall ?M2741 (?M2742 :: ?M2743)" with 
"Forall P l'".
DEBUG LTAC Evaluated term: H