CLI support for `enableConditionalDirectives`.

pkg/analyzer_cli/lib/src/options.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analyzer_cli.src.options;
 
 import 'dart:io';
 
 import 'package:analyzer_cli/src/driver.dart';
 import 'package:args/args.dart';
@@ skipping 27 matching lines @@
 
   /// A table mapping the names of defined variables to their values.
   final Map<String, String> definedVariables;
 
   /// Whether to report hints
   final bool disableHints;
 
   /// Whether to display version information
   final bool displayVersion;
 
+  /// Whether to enable conditional directives (DEP 40).
+  final bool enableConditionalDirectives;
+
   /// Whether to enable null-aware operators (DEP 9).
   final bool enableNullAwareOperators;
 
   /// Whether to strictly follow the specification when generating warnings on
   /// "call" methods (fixes dartbug.com/21938).
   final bool enableStrictCallChecks;
 
   /// Whether to relax restrictions on mixins (DEP 34).
   final bool enableSuperMixins;
 
@@ skipping 63 matching lines @@
   final bool strongMode;
 
   /// Initialize options from the given parsed [args].
   CommandLineOptions._fromArgs(
       ArgResults args, Map<String, String> definedVariables)
       : dartSdkPath = args['dart-sdk'],
         definedVariables = definedVariables,
         analysisOptionsFile = args['options'],
         disableHints = args['no-hints'],
         displayVersion = args['version'],
+        enableConditionalDirectives = args['enable-conditional-directives'],
         enableNullAwareOperators = args['enable-null-aware-operators'],
         enableStrictCallChecks = args['enable-strict-call-checks'],
         enableSuperMixins = args['supermixin'],
         enableTypeChecks = args['enable_type_checks'],
         hintsAreFatal = args['fatal-hints'],
         ignoreUnrecognizedFlags = args['ignore-unrecognized-flags'],
         lints = args['lints'],
         log = args['log'],
         machineFormat = args['machine'] || args['format'] == 'machine',
         packageMode = args['package-mode'],
@@ skipping 187 matching lines @@
       ..addFlag('enable-async',
           help: 'Enable support for the proposed async feature.',
           defaultsTo: false,
           negatable: false,
           hide: true)
       ..addFlag('enable-enum',
           help: 'Enable support for the proposed enum feature.',
           defaultsTo: false,
           negatable: false,
           hide: true)
+      ..addFlag('enable-conditional-directives',
+          help: 'Enable support for conditional directives (DEP 40).',
+          defaultsTo: false,
+          negatable: false,
+          hide: true)
       ..addFlag('enable-null-aware-operators',
           help: 'Enable support for null-aware operators (DEP 9).',
           defaultsTo: false,
           negatable: false,
           hide: true)
       ..addFlag('enable-strict-call-checks',
           help: 'Fix issue 21938.',
           defaultsTo: false,
           negatable: false,
           hide: true)
@@ skipping 225 matching lines @@
 
   int _getNextFlagIndex(args, i) {
     for (; i < args.length; ++i) {
       if (args[i].startsWith('--')) {
         return i;
       }
     }
     return i;
   }
 }