Goal:
    x : V.t  s : VSet.t  y : V.t  H0 : x = y  H1 : x = y
  ============================
   (x = y)


DEBUG:Going to execute:
<Coq.Init.Tauto.is_empty> flags X1; elim H
Level 4: Backtrace:

In environment
x : V.t
s : VSet.t
y : V.t
H0, H1 : x = y
Unable to unify "y" with "x".
Level 4: Backtrace:

In environment
x : V.t
s : VSet.t
y : V.t
H0, H1 : x = y
Unable to unify "y" with "x".
Level 5: Backtrace:

In environment
x : V.t
s : VSet.t
y : V.t
H0, H1 : x = y
Unable to unify "y" with "x".
Level 5: Backtrace:

In environment
x : V.t
s : VSet.t
y : V.t
H0, H1 : x = y
Unable to unify "y" with "x".
Level 4: Backtrace:

In environment
x : V.t
s : VSet.t
y : V.t
H0, H1 : x = y
Unable to unify "y" with "x".
Level 4: Backtrace:

In environment
x : V.t
s : VSet.t
y : V.t
H0, H1 : x = y
Unable to unify "y" with "x".