class Steep::Subtyping::Constraints::UnsatisfiedInvariantError::VariablesFreeVariablesNotDisjoint

def initialize(var: nil, lower_bound: nil, upper_bound: nil)
  @var = var
  @lower_bound = lower_bound
  @upper_bound = upper_bound
end

def message
  "Variables and FV(constraints) should be disjoint (#{var}, #{lower_bound}, #{upper_bound})"
end