Enable syntax-only support for generic functions by default, take 2.

pkg/compiler/lib/src/options.dart

 // Copyright (c) 2016, 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 dart2js.src.options;
 
 import '../compiler.dart' show PackagesDiscoveryProvider;
 import 'commandline_options.dart' show Flags;
 
 /// Options used for parsing.
@@ skipping 271 matching lines @@
         terseDiagnostics: _hasOption(options, Flags.terse),
         suppressWarnings: _hasOption(options, Flags.suppressWarnings),
         suppressHints: _hasOption(options, Flags.suppressHints),
         shownPackageWarnings:
             _extractOptionalCsvOption(options, Flags.showPackageWarnings),
         disableInlining: _hasOption(options, Flags.disableInlining),
         disableTypeInference: _hasOption(options, Flags.disableTypeInference),
         dumpInfo: _hasOption(options, Flags.dumpInfo),
         enableAssertMessage: _hasOption(options, Flags.enableAssertMessage),
         enableGenericMethodSyntax:
-            _hasOption(options, Flags.genericMethodSyntax),
+            true, // No check for `Flags.genericMethodSyntax`: always enabled.
         enableInitializingFormalAccess:
             _hasOption(options, Flags.initializingFormalAccess),
         enableExperimentalMirrors:
             _hasOption(options, Flags.enableExperimentalMirrors),
         enableMinification: _hasOption(options, Flags.minify),
         enableNativeLiveTypeAnalysis:
             !_hasOption(options, Flags.disableNativeLiveTypeAnalysis),
         enableTypeAssertions: _hasOption(options, Flags.enableCheckedMode),
         enableUserAssertions: _hasOption(options, Flags.enableCheckedMode),
         generateCodeWithCompileTimeErrors:
@@ skipping 432 matching lines @@
 }
 
 /// Locations of the platform descriptor files relative to the library root.
 const String _clientPlatform = "lib/dart_client.platform";
 const String _serverPlatform = "lib/dart_server.platform";
 const String _sharedPlatform = "lib/dart_shared.platform";
 
 const String _UNDETERMINED_BUILD_ID = "build number could not be determined";
 const bool _forceIncrementalSupport =
     const bool.fromEnvironment('DART2JS_EXPERIMENTAL_INCREMENTAL_SUPPORT');