class Steep::Subtyping::Constraints::UnsatisfiedInvariantError::UnknownsFreeVariableNotDisjoint

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

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