fix #27259, implement covariance checking for strong mode and DDC

pkg/dev_compiler/lib/src/compiler/compiler.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.
 
 import 'dart:collection' show HashSet, Queue;
 import 'dart:convert' show JSON;
 import 'dart:io' show File;
 
 import 'package:analyzer/analyzer.dart'
     show AnalysisError, CompilationUnit, ErrorSeverity;
@@ skipping 249 matching lines @@
   /// Whether to force compilation of code with static errors.
   final bool unsafeForceCompile;
 
   /// Whether to compile code in a more permissive REPL mode allowing access
   /// to private members across library boundaries.
   final bool replCompile;
 
   /// Whether to emit Closure Compiler-friendly code.
   final bool closure;
 
-  /// Hoist the types at instance creation sites.
-  final bool hoistInstanceCreation;
-
-  /// Hoist types from class signatures.
-  final bool hoistSignatureTypes;
-
-  /// Name types in type tests.
-  final bool nameTypeTests;
-
-  /// Hoist types in type tests.
-  final bool hoistTypeTests;
-
   /// Enable ES6 destructuring of named parameters. Off by default.
   ///
   /// Older V8 versions do not accept default values with destructuring in
   /// arrow functions yet (e.g. `({a} = {}) => 1`) but happily accepts them
   /// with regular functions (e.g. `function({a} = {}) { return 1 }`).
   ///
   /// Supporting the syntax:
   /// * Chrome Canary (51)
   /// * Firefox
   ///
@@ skipping 15 matching lines @@
       {this.sourceMap: true,
       this.sourceMapComment: true,
       this.inlineSourceMap: false,
       this.summarizeApi: true,
       this.summaryExtension: 'sum',
       this.unsafeForceCompile: false,
       this.replCompile: false,
       this.emitMetadata: false,
       this.closure: false,
       this.destructureNamedParams: false,
-      this.hoistInstanceCreation: true,
-      this.hoistSignatureTypes: false,
-      this.nameTypeTests: true,
-      this.hoistTypeTests: true,
       this.bazelMapping: const {},
       this.summaryOutPath});
 
   CompilerOptions.fromArguments(ArgResults args)
       : sourceMap = args['source-map'],
         sourceMapComment = args['source-map-comment'],
         inlineSourceMap = args['inline-source-map'],
         summarizeApi = args['summarize'],
         summaryExtension = args['summary-extension'],
         unsafeForceCompile = args['unsafe-force-compile'],
         replCompile = args['repl-compile'],
         emitMetadata = args['emit-metadata'],
         closure = args['closure-experimental'],
         destructureNamedParams = args['destructure-named-params'],
-        hoistInstanceCreation = args['hoist-instance-creation'],
-        hoistSignatureTypes = args['hoist-signature-types'],
-        nameTypeTests = args['name-type-tests'],
-        hoistTypeTests = args['hoist-type-tests'],
         bazelMapping = _parseBazelMappings(args['bazel-mapping']),
         summaryOutPath = args['summary-out'];
 
   static void addArguments(ArgParser parser, {bool hide: true}) {
     parser
       ..addFlag('summarize', help: 'emit an API summary file', defaultsTo: true)
       ..addOption('summary-extension',
           help: 'file extension for Dart summary files',
           defaultsTo: 'sum',
           hide: hide)
@@ skipping 16 matching lines @@
       ..addFlag('unsafe-force-compile',
           help: 'Compile code even if it has errors. ಠ_ಠ\n'
               'This has undefined behavior!',
           defaultsTo: false,
           hide: hide)
       ..addFlag('repl-compile',
           help: 'Compile code more permissively when in REPL mode\n'
               'allowing access to private members across library boundaries.',
           defaultsTo: false,
           hide: hide)
-      ..addFlag('hoist-instance-creation',
-          help: 'Hoist the class type from generic instance creations',
-          defaultsTo: true,
-          hide: hide)
-      ..addFlag('hoist-signature-types',
-          help: 'Hoist types from class signatures',
-          defaultsTo: false,
-          hide: hide)
-      ..addFlag('name-type-tests',
-          help: 'Name types used in type tests', defaultsTo: true, hide: hide)
-      ..addFlag('hoist-type-tests',
-          help: 'Hoist types used in type tests', defaultsTo: true, hide: hide)
       ..addOption('bazel-mapping',
           help:
               '--bazel-mapping=genfiles/to/library.dart,to/library.dart uses \n'
               'to/library.dart as the path for library.dart in source maps.',
           allowMultiple: true,
           splitCommas: false,
           hide: hide)
       ..addOption('summary-out',
           help: 'location to write the summary file', hide: hide);
   }
@@ skipping 230 matching lines @@
     case "dart":
     case "package":
     case "file":
       // A valid URI.
       return uri;
     default:
       // Assume a file path.
       return new Uri.file(path.absolute(source));
   }
 }