Review

class MakeDeclaredNamesUnique {
  /**
   * Walks the stack of name maps and finds the replacement name for the
   * current scope.
   */
  private String getReplacementName(String oldName) {
    for (Renamer names : nameStack) {
      String newName = names.getReplacementName(oldName);
      if (newName != null) {
        return newName;
      }
    }
    return null;
  }
}

class MakeDeclaredNamesUnique.Renamer {
    /**
     * @return A replacement name, null if oldName is unknown or should not
     * be replaced.
     */
    String getReplacementName(String oldName);
}

class MakeDeclaredNamesUnique.ContextualRenamer {
    @Override
    public String getReplacementName(String oldName) {
      return declarations.get(oldName);
    }
}

class MakeDeclaredNamesUnique.InlineRenamer {
    @Override
    public String getReplacementName(String oldName) {
      return declarations.get(oldName);
    }

}