anchor.diff:      print('Usage: a single absolute file path to analyze.');
       io.exit(1);
     }
  -  await CompletionCoverageMetrics(args[0]).compute();
  +  var corpus = args[0] == '--corpus';
  +  var rootPath = corpus ? args[1] : args[0];
  +  await CompletionCoverageMetrics(rootPath).compute(corpus: corpus);
     io.exit(0);
   }
   
  
positive.code:   /// The analysis root path that this CompletionMetrics class will be computed.
    String get rootPath => _rootPath;
  
    void compute() async {
      print('Analyzing root: \"$_rootPath\"');
  
      if (!io.Directory(_rootPath).existsSync()) {
  
negative.code: import 'package:analyzer/src/dart/analysis/byte_store.dart';
  import 'package:analyzer/src/generated/engine.dart';
  import 'package:analyzer/src/services/available_declarations.dart';
  import 'package:path/path.dart' as path;
  
  import 'metrics_util.dart';
  import 'visitors.dart';
  