# File lib/type_checker.rb, line 780
  def process_or(exp)
    rhs = process exp.shift
    lhs = process exp.shift

    rhs_type = rhs.sexp_type
    lhs_type = lhs.sexp_type

    rhs_type.unify lhs_type
    rhs_type.unify Type.bool

    return t(:or, rhs, lhs, Type.bool)
  end