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

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

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

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

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

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