Make pub strong-mode clean.

lib/src/global_packages.dart

 // Copyright (c) 2014, 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:async';
 import 'dart:io';
 
 import 'package:path/path.dart' as p;
 import 'package:barback/barback.dart';
 import 'package:pub_semver/pub_semver.dart';
@@ skipping 193 matching lines @@
 
       return environment.precompileExecutables(package, binDir);
     });
   }
 
   /// Downloads [id] into the system cache if it's a cached package.
   Future _cacheDependency(PackageId id) async {
     if (id.isRoot) return;
 
     var source = cache.source(id.source);
-    if (source is! CachedSource) return;
-
-    await source.downloadToSystemCache(id);
+    if (source is CachedSource) await source.downloadToSystemCache(id);
   }
 
   /// Finishes activating package [package] by saving [lockFile] in the cache.
   void _writeLockFile(String package, LockFile lockFile) {
     ensureDir(p.join(_directory, package));
 
     // TODO(nweiz): This cleans up Dart 1.6's old lockfile location. Remove it
     // when Dart 1.6 is old enough that we don't think anyone will have these
     // lockfiles anymore (issue 20703).
     var oldPath = p.join(_directory, "$package.lock");
@@ skipping 198 matching lines @@
       return '${log.bold(id.name)} ${id.version}';
     }
   }
 
   /// Repairs any corrupted globally-activated packages and their binstubs.
   ///
   /// Returns a pair of two lists of strings. The first indicates which packages
   /// were successfully re-activated; the second indicates which failed.
   Future<Pair<List<String>, List<String>>> repairActivatedPackages()
       async {
-    var executables = {};
+    var executables = <String, List<String>>{};
     if (dirExists(_binStubDir)) {
       for (var entry in listDir(_binStubDir)) {
         try {
           var binstub = readTextFile(entry);
           var package = _binStubProperty(binstub, "Package");
           if (package == null) {
             throw new ApplicationException("No 'Package' property.");
           }
 
           var executable = _binStubProperty(binstub, "Executable");
           if (executable == null) {
             throw new ApplicationException("No 'Executable' property.");
           }
 
           executables.putIfAbsent(package, () => []).add(executable);
         } catch (error, stackTrace) {
           log.error(
               "Error reading binstub for "
                   "\"${p.basenameWithoutExtension(entry)}\"",
               error, stackTrace);
 
           tryDeleteEntry(entry);
         }
       }
     }
 
-    var successes = [];
-    var failures = [];
+    var successes = <String>[];
+    var failures = <String>[];
     if (dirExists(_directory)) {
       for (var entry in listDir(_directory)) {
         var id;
         try {
           id = _loadPackageId(entry);
           log.message("Reactivating ${log.bold(id.name)} ${id.version}...");
 
           var entrypoint = find(id.name);
           var snapshots = await _precompileExecutables(entrypoint, id.name);
           var packageExecutables = executables.remove(id.name);
@@ skipping 70 matching lines @@
     // list of executables has changed.
     _deleteBinStubs(package.name);
 
     if ((executables != null && executables.isEmpty) ||
         package.pubspec.executables.isEmpty) {
       return;
     }
 
     ensureDir(_binStubDir);
 
-    var installed = [];
-    var collided = {};
+    var installed = <String>[];
+    var collided = <String, String>{};
     var allExecutables = ordered(package.pubspec.executables.keys);
     for (var executable in allExecutables) {
       if (executables != null && !executables.contains(executable)) continue;
 
       var script = package.pubspec.executables[executable];
 
       var previousPackage = _createBinStub(package, executable, script,
           overwrite: overwriteBinStubs, snapshot: snapshots[script]);
       if (previousPackage != null) {
         collided[executable] = previousPackage;
@@ skipping 234 matching lines @@
   }
 
   /// Returns the value of the property named [name] in the bin stub script
   /// [source].
   String _binStubProperty(String source, String name) {
     var pattern = new RegExp(quoteRegExp(name) + r": ([a-zA-Z0-9_-]+)");
     var match = pattern.firstMatch(source);
     return match == null ? null : match[1];
   }
 }