Goal:
    A : Type  R : ReflectEq A  x : A  y : A  Heq_anonymous : false = (x == y)
  ============================
   (x <> y)


DEBUG:Going to execute:
match H with
           | H' => fail 2
           | _ => unify X Y; clear H' || clear H
           end
Level 4: Backtrace:

In environment
A : Type
R : ReflectEq A
x, y : A
Heq_anonymous : false = (x == y)
Unable to unify "A" with "false = (x == y)".
Level 4: Backtrace:

In environment
A : Type
R : ReflectEq A
x, y : A
Heq_anonymous : false = (x == y)
Unable to unify "A" with "false = (x == y)".
Level 4: Backtrace:

In environment
A : Type
R : ReflectEq A
x, y : A
Heq_anonymous : false = (x == y)
Unable to unify "A" with "false = (x == y)".
Level 4: Backtrace:

In environment
A : Type
R : ReflectEq A
x, y : A
Heq_anonymous : false = (x == y)
Unable to unify "A" with "false = (x == y)".
Level 3: Backtrace:

In environment
A : Type
R : ReflectEq A
x, y : A
Heq_anonymous : false = (x == y)
Unable to unify "A" with "false = (x == y)".