// This qualifier saves the day; solve constraints WITHOUT IT
// qualif Zog(v:a) : (10 <= v)

bind 0 a : {v: int | $k0}

constraint:
  env [ ]
  lhs {v : int | (v = 10)}
  rhs {v : int | $k0}
  id 1 

constraint:
  env [ ]
  lhs {v : int | v = 20}
  rhs {v : int | $k0}
  id 2 

constraint:
  env [ 0 ]
  lhs {v : int | v = a}
  rhs {v : int | 10 <= v}
  id 3 

wf:
  env [ ]
  reft {v: int | $k0}