Goal:
    A : Type  t : A  P : A → A → Type  hd' : A  tl : list A  p : P t hd'
  ============================
   (t = hd')


DEBUG:Going to execute:
<Coq.Init.Tauto.is_empty> flags X1; elim H
Level 3: Backtrace:

In environment
A : Type
t : A
P : A → A → Type
hd' : A
tl : list A
p : P t hd'
Unable to unify "hd'" with "t".
Level 3: Backtrace:

In environment
A : Type
t : A
P : A → A → Type
hd' : A
tl : list A
p : P t hd'
Unable to unify "hd'" with "t".
Level 4: Backtrace:

In environment
A : Type
t : A
P : A → A → Type
hd' : A
tl : list A
p : P t hd'
Unable to unify "hd'" with "t".
Level 4: Backtrace:

In environment
A : Type
t : A
P : A → A → Type
hd' : A
tl : list A
p : P t hd'
Unable to unify "hd'" with "t".
Level 3: Backtrace:

In environment
A : Type
t : A
P : A → A → Type
hd' : A
tl : list A
p : P t hd'
Unable to unify "hd'" with "t".
Level 3: Backtrace:

In environment
A : Type
t : A
P : A → A → Type
hd' : A
tl : list A
p : P t hd'
Unable to unify "hd'" with "t".