anchor.diff:    static String generateFlutterId(String id) {
       String flutterId = id;
       // Exact identifier rewrites.
  -    for (final MapEntry<String, String> rewritePair in identifierExactRewrites.entries) {
  +    for (final MapEntry<String, String> rewritePair in _identifierExactRewrites.entries) {
         final String shortId = Icon._generateShortId(id);
         if (shortId == rewritePair.key) {
           flutterId = id.replaceFirst(
             rewritePair.key,
  -          identifierExactRewrites[rewritePair.key]!,
  +          _identifierExactRewrites[rewritePair.key]!,
           );
         }
       }
       // Prefix identifier rewrites.
  -    for (final MapEntry<String, String> rewritePair in identifierPrefixRewrites.entries) {
  +    for (final MapEntry<String, String> rewritePair in _identifierPrefixRewrites.entries) {
         if (id.startsWith(rewritePair.key)) {
           flutterId = id.replaceFirst(
             rewritePair.key,
  -          identifierPrefixRewrites[rewritePair.key]!,
  +          _identifierPrefixRewrites[rewritePair.key]!,
           );
         }
       }
  
positive.code: };
  
  // Rewrite certain Flutter IDs (numbers) using prefix matching.
  const Map<String, String> identifierPrefixRewrites = <String, String>{
    '1': 'one_',
    '2': 'two_',
    '3': 'three_',
  
negative.code: };
  
  // Rewrite certain Flutter IDs (reserved keywords) using exact matching.
  const Map<String, String> _identifierExactRewrites = <String, String>{
    'class': 'class_',
    'new': 'new_',
    'switch': 'switch_',
  