anchor.diff:  class OptionsParser {
     static final List<_Option> _options = [
       _Option('mode', 'Mode in which to run the tests.',
  -        abbr: 'm', values: ['all']..addAll(Mode.names)),
  -    _Option('sanitizer', 'Sanitizer in which to run the tests.',
  -        defaultsTo: Sanitizer.none.name,
  -        values: ['all']..addAll(Sanitizer.names)),
  +        abbr: 'm', values: ['all', ...Mode.names]),
       _Option(
           'compiler',
           '''How the Dart code should be compiled or statically processed.
  -
  -none:          Do not compile the Dart code.
  -precompiler:   Compile into AOT snapshot before running the test.
  -dart2js:       Compile to JavaScript using dart2js.
  -dart2analyzer: Perform static analysis on Dart code using the analyzer.
  -compareAnalyzerCfe: Compare analyzer and common front end representations.
  -app_jit:       Compile the Dart code into an app snapshot.
  -app_jitk:      Compile the Dart code into Kernel and then into an app snapshot.
  -dartk:         Compile the Dart code into Kernel before running test.
  -dartkb:        Compile the Dart code into Kernel with bytecode before running test.
  -dartkp:        Compile the Dart code into Kernel and then Kernel into AOT
  -               snapshot before running the test.
  -spec_parser:   Parse Dart code using the specification parser.''',
  +none:                 Do not compile the Dart code.
  +dart2js:              Compile to JavaScript using dart2js.
  +dart2analyzer:        Perform static analysis on Dart code using the analyzer.
  +compare_analyzer_cfe: Compare analyzer and common front end representations.
  +dartdevc:             Compile to JavaScript using dart2js.
  +dartdevk:             Compile to JavaScript using dartdevk.
  +app_jitk:             Compile the Dart code into Kernel and then into an app
  +                      snapshot.
  +dartk:                Compile the Dart code into Kernel before running test.
  +dartkb:               Compile the Dart code into Kernel with bytecode before
  +                      running test.
  +dartkp:               Compile the Dart code into Kernel and then Kernel into
  +                      AOT snapshot before running the test.
  +spec_parser:          Parse Dart code using the specification parser.
  +
  +fasta:                Compile using CFE for errors, but do not run.
  +''',
           abbr: 'c',
           values: Compiler.names),
       _Option(
  
positive.code:     }
  
      var runtimeNames = data["runtime"] as String;
      var runtimes = <Runtime>[];
      if (runtimeNames != null) {
        runtimes.addAll(runtimeNames.split(",").map(Runtime.find));
      }
  
      var compilerNames = data["compiler"] as String;
      var compilers = <Compiler>[];
      if (compilerNames != null) {
        compilers.addAll(compilerNames.split(",").map(Compiler.find));
      }
  
      // Pick default compilers or runtimes if only one or the other is provided.
      if (runtimes.isEmpty) {
  
negative.code: arm, armv6, arm64,
  simarm, simarmv6, simarm64, arm_x64''',
          abbr: 'a',
          values: ['all', ...Architecture.names],
          defaultsTo: Architecture.x64.name,
          hide: true),
      _Option('system', 'The operating system to run tests on.',
  