private boolean isRemovableVar(Var var) {
    // Global variables are off-limits if the user might be using them.
    if (!removeGlobals && var.isGlobal()) {
      return false;
    }

    // Referenced variables are off-limits.
    if (referenced.contains(var)) {
      return false;
    }

    // Exported variables are off-limits.
    if (codingConvention.isExported(var.getName())) {
      return false;
    }

    return true;
  }