anchor.diff:            // we need to run update-packages to recapture the transitive deps.
             printStatus(
               'Warning: pubspec in ${directory.path} has invalid dependencies. '
  -            'Please run "flutter update-packages" --force-upgrade to update them correctly.'  
  +            'Please run "flutter update-packages" --force-upgrade to update them correctly.'
             );
            } else {
              // everything is correct in the pubspec.
  
positive.code:     // Which dependencies we need to handle for the transitive and dev dependency sections.
      final Set<String> transitiveDependencies = new Set<String>();
      final Set<String> transitiveDevDependencies = new Set<String>();
      
      // Merge the lists of dependencies we've seen in this file from dependencies, dev dependencies,
      // and the dependencies we know this file mentions that are already pinned 
      // (and which didn't get special processing above).
      final Set<String> implied = new Set<String>.from(directDependencies)
        ..addAll(specialDependencies)
  
negative.code:   final List<PubspecLine> inputData; // Each line of the pubspec.yaml file, parsed(ish).
  
    /// The package checksum.
    ///
    /// If this was not found in the pubspec, a synthetic checksum is created
    /// with a value of `-1`.
    final PubspecChecksum checksum;
  