enable lints prefer_spread_collections and prefer_inlined_adds (#35189)

analysis_options.yaml

@@ -33,11 +33,11 @@ analyzer:
     # Please see https://github.com/flutter/flutter/pull/24528 for details.
     sdk_version_async_exported_from_core: ignore
   exclude:
-    - 'bin/cache/**'
+    - "bin/cache/**"
     # the following two are relative to the stocks example and the flutter package respectively
     # see https://github.com/dart-lang/sdk/issues/28463
-    - 'lib/i18n/stock_messages_*.dart'
-    - 'lib/src/http/**'
+    - "lib/i18n/stock_messages_*.dart"
+    - "lib/src/http/**"
 
 linter:
   rules:
@@ -143,7 +143,7 @@ linter:
     # - prefer_if_elements_to_conditional_expressions # not yet tested
     # - prefer_if_null_operators # not yet tested
     - prefer_initializing_formals
-    # - prefer_inlined_adds # not yet tested
+    - prefer_inlined_adds
     # - prefer_int_literals # not yet tested
     # - prefer_interpolation_to_compose_strings # not yet tested
     - prefer_is_empty
@@ -152,7 +152,7 @@ linter:
     # - prefer_mixin # https://github.com/dart-lang/language/issues/32
     # - prefer_null_aware_operators # disable until NNBD, see https://github.com/flutter/flutter/pull/32711#issuecomment-492930932
     - prefer_single_quotes
-    # - prefer_spread_collections # not yet tested
+    - prefer_spread_collections
     - prefer_typing_uninitialized_variables
     - prefer_void_to_null
     # - provide_deprecation_message # not yet tested

dev/benchmarks/macrobenchmarks/lib/src/cubic_bezier.dart

@@ -117,11 +117,12 @@ class AnimatedBezierState extends State<AnimatedBezier>
   AnimationController controller;
   CurvedAnimation curve;
   bool isPlaying = false;
-  List<List<Point>> pointList = <List<Point>>[]
-    ..add(<Point>[])
-    ..add(<Point>[])
-    ..add(<Point>[])
-    ..add(<Point>[]);
+  List<List<Point>> pointList = <List<Point>>[
+    <Point>[],
+    <Point>[],
+    <Point>[],
+    <Point>[],
+  ];
   bool isReversed = false;
 
   List<PathDetail> _playForward() {

dev/bots/analyze-sample-code.dart

@@ -286,13 +286,14 @@ class SampleChecker {
           '--snapshot=$_snippetsSnapshotPath',
           '--snapshot-kind=app-jit',
           path.canonicalize(_snippetsExecutable),
-        ]..addAll(args),
+          ...args,
+        ],
         workingDirectory: workingDirectory,
       );
     } else {
       return Process.runSync(
         _dartExecutable,
-        <String>[path.canonicalize(_snippetsSnapshotPath)]..addAll(args),
+        <String>[path.canonicalize(_snippetsSnapshotPath), ...args],
         workingDirectory: workingDirectory,
       );
     }
@@ -311,7 +312,8 @@ class SampleChecker {
     final List<String> args = <String>[
       '--output=${outputFile.absolute.path}',
       '--input=${inputFile.absolute.path}',
-    ]..addAll(snippet.args);
+      ...snippet.args,
+    ];
     print('Generating snippet for ${snippet.start?.filename}:${snippet.start?.line}');
     final ProcessResult process = _runSnippetsScript(args);
     if (process.exitCode != 0) {
@@ -854,9 +856,11 @@ class Section {
         ),
       );
     }
-    return Section(<Line>[Line(prefix)]
-      ..addAll(codeLines)
-      ..add(Line(postfix)));
+    return Section(<Line>[
+      Line(prefix),
+      ...codeLines,
+      Line(postfix),
+    ]);
   }
   Line get start => code.firstWhere((Line line) => line.filename != null);
   final List<Line> code;
@@ -868,8 +872,8 @@ class Section {
 /// analyzed.
 class Snippet {
   Snippet({this.start, List<String> input, List<String> args, this.serial}) {
-    this.input = <String>[]..addAll(input);
-    this.args = <String>[]..addAll(args);
+    this.input = input.toList();
+    this.args = args.toList();
   }
   final Line start;
   final int serial;

dev/bots/analyze.dart

@@ -260,7 +260,9 @@ Future<EvalResult> _evalCommand(String executable, List<String> arguments, {
 Future<void> _runFlutterAnalyze(String workingDirectory, {
   List<String> options = const <String>[],
 }) {
-  return runCommand(flutter, <String>['analyze', '--dartdocs']..addAll(options),
+  return runCommand(
+    flutter,
+    <String>['analyze', '--dartdocs', ...options],
     workingDirectory: workingDirectory,
   );
 }
@@ -456,7 +458,10 @@ List<T> _deepSearch<T>(Map<T, Set<T>> map, T start, [ Set<T> seen ]) {
     final List<T> result = _deepSearch<T>(
       map,
       key,
-      (seen == null ? <T>{start} : Set<T>.from(seen))..add(key),
+      <T>{
+        if (seen == null) start else ...seen,
+        key,
+      },
     );
     if (result != null) {
       result.insert(0, start);

dev/bots/prepare_package.dart

@@ -381,14 +381,14 @@ class ArchiveCreator {
 
   Future<String> _runFlutter(List<String> args, {Directory workingDirectory}) {
     return _processRunner.runProcess(
-      <String>[_flutter]..addAll(args),
+      <String>[_flutter, ...args],
       workingDirectory: workingDirectory ?? flutterRoot,
     );
   }
 
   Future<String> _runGit(List<String> args, {Directory workingDirectory}) {
     return _processRunner.runProcess(
-      <String>['git']..addAll(args),
+      <String>['git', ...args],
       workingDirectory: workingDirectory ?? flutterRoot,
     );
   }
@@ -574,14 +574,14 @@ class ArchivePublisher {
   }) async {
     if (platform.isWindows) {
       return _processRunner.runProcess(
-        <String>['python', path.join(platform.environment['DEPOT_TOOLS'], 'gsutil.py'), '--']..addAll(args),
+        <String>['python', path.join(platform.environment['DEPOT_TOOLS'], 'gsutil.py'), '--', ...args],
         workingDirectory: workingDirectory,
         failOk: failOk,
       );
     }
 
     return _processRunner.runProcess(
-      <String>['gsutil.py', '--']..addAll(args),
+      <String>['gsutil.py', '--', ...args],
       workingDirectory: workingDirectory,
       failOk: failOk,
     );

dev/bots/pubspec.yaml

@@ -3,7 +3,7 @@ description: Scripts which run on bots.
 
 environment:
   # The pub client defaults to an <2.0.0 sdk constraint which we need to explicitly overwrite.
-  sdk: ">=2.2.0 <3.0.0"
+  sdk: ">=2.2.2 <3.0.0"
 
 dependencies:
   path: 1.6.2

dev/bots/test.dart

@@ -220,7 +220,7 @@ Future<void> _runToolCoverage() async {
     final List<String> testGroup = tests[i];
     await runCommand(
       dart,
-      <String>[path.join('tool', 'tool_coverage.dart'), '--']..addAll(testGroup),
+      <String>[path.join('tool', 'tool_coverage.dart'), '--', ...testGroup],
       workingDirectory: toolRoot,
       environment: <String, String>{
         'FLUTTER_ROOT': flutterRoot,
@@ -791,7 +791,7 @@ Future<void> _runFlutterTest(String workingDirectory, {
   Map<String, String> environment,
   List<String> tests = const <String>[],
 }) async {
-  final List<String> args = <String>['test']..addAll(options);
+  final List<String> args = <String>['test', ...options];
   if (flutterTestArgs != null && flutterTestArgs.isNotEmpty)
     args.addAll(flutterTestArgs);
 

dev/bots/test/fake_process_manager.dart

@@ -35,8 +35,7 @@ class FakeProcessManager extends Mock implements ProcessManager {
   set fakeResults(Map<String, List<ProcessResult>> value) {
     _fakeResults = <String, List<ProcessResult>>{};
     for (String key in value.keys) {
-      _fakeResults[key] = <ProcessResult>[]
-        ..addAll(value[key] ?? <ProcessResult>[ProcessResult(0, 0, '', '')]);
+      _fakeResults[key] = (value[key] ?? <ProcessResult>[ProcessResult(0, 0, '', '')]).toList();
     }
   }
 

dev/bots/unpublish_package.dart

@@ -334,7 +334,7 @@ class ArchiveUnpublisher {
     bool failOk = false,
     bool confirm = false,
   }) async {
-    final List<String> command = <String>['gsutil', '--']..addAll(args);
+    final List<String> command = <String>['gsutil', '--', ...args];
     if (confirm) {
       return _processRunner.runProcess(
         command,
@@ -358,7 +358,7 @@ class ArchiveUnpublisher {
         print('  $file');
       }
     }
-    await _runGsUtil(<String>['rm']..addAll(files), failOk: true, confirm: confirmed);
+    await _runGsUtil(<String>['rm', ...files], failOk: true, confirm: confirmed);
   }
 
   Future<String> _cloudReplaceDest(String src, String dest) async {

dev/devicelab/bin/tasks/build_mode_test.dart

@@ -17,7 +17,7 @@ Future<String> runFlutterAndQuit(List<String> args, Device device) async {
   print('run: starting...');
   final Process run = await startProcess(
     path.join(flutterDirectory.path, 'bin', 'flutter'),
-    <String>['run', '--suppress-analytics']..addAll(args),
+    <String>['run', '--suppress-analytics', ...args],
     isBot: false, // we just want to test the output, not have any debugging info
   );
   final List<String> stdout = <String>[];
@@ -61,8 +61,13 @@ void main() {
     Future<void> checkMode(String mode, {bool releaseExpected = false, bool dynamic = false}) async {
       await inDirectory(appDir, () async {
         print('run: starting $mode test...');
-        final List<String> args = <String>['--$mode']..addAll(dynamic ? <String>['--dynamic'] : const <String>[]);
-        args.addAll(<String>['-d', device.deviceId, 'lib/build_mode.dart']);
+        final List<String> args = <String>[
+          '--$mode',
+          if (dynamic) '--dynamic',
+          '-d',
+          device.deviceId,
+          'lib/build_mode.dart',
+        ];
         final String stdout = await runFlutterAndQuit(args, device);
         if (!stdout.contains('>>> Release: $releaseExpected <<<')) {
           throw "flutter run --$mode ${dynamic ? '--dynamic ' : ''}didn't set kReleaseMode properly";

dev/devicelab/bin/tasks/flutter_run_test.dart

@@ -40,7 +40,7 @@ Future<TaskResult> createFlutterRunTask() async {
   await inDirectory<void>(flutterGalleryDir, () async {
     startProcess(
       path.join(flutterDirectory.path, 'bin', 'flutter'),
-      <String>['run']..addAll(options),
+      <String>['run', ...options],
       environment: null,
     );
     final Completer<void> finished = Completer<void>();

dev/devicelab/bin/tasks/uncaught_image_error_linux.dart

@@ -29,8 +29,9 @@ Future<void> main() async {
         deviceId,
       ];
       final Process process = await startProcess(
-          path.join(flutterDirectory.path, 'bin', 'flutter'),
-          <String>['run']..addAll(options));
+        path.join(flutterDirectory.path, 'bin', 'flutter'),
+        <String>['run', ...options],
+      );
 
       final Stream<String> lines = process.stdout
         .transform(utf8.decoder)

dev/devicelab/lib/framework/adb.dart

@@ -262,17 +262,17 @@ class AndroidDevice implements Device {
 
   /// Executes [command] on `adb shell` and returns its exit code.
   Future<void> shellExec(String command, List<String> arguments, { Map<String, String> environment }) async {
-    await adb(<String>['shell', command]..addAll(arguments), environment: environment);
+    await adb(<String>['shell', command, ...arguments], environment: environment);
   }
 
   /// Executes [command] on `adb shell` and returns its standard output as a [String].
   Future<String> shellEval(String command, List<String> arguments, { Map<String, String> environment }) {
-    return adb(<String>['shell', command]..addAll(arguments), environment: environment);
+    return adb(<String>['shell', command, ...arguments], environment: environment);
   }
 
   /// Runs `adb` with the given [arguments], selecting this device.
   Future<String> adb(List<String> arguments, { Map<String, String> environment }) {
-    return eval(adbPath, <String>['-s', deviceId]..addAll(arguments), environment: environment, canFail: false);
+    return eval(adbPath, <String>['-s', deviceId, ...arguments], environment: environment, canFail: false);
   }
 
   @override

dev/devicelab/lib/framework/apk_utils.dart

@@ -194,7 +194,7 @@ android {
   Future<ProcessResult> resultOfFlutterCommand(String command, List<String> options) {
     return Process.run(
       path.join(flutterDirectory.path, 'bin', 'flutter'),
-      <String>[command]..addAll(options),
+      <String>[command, ...options],
       workingDirectory: rootPath,
     );
   }

dev/devicelab/lib/framework/utils.dart

@@ -235,7 +235,7 @@ Future<Process> startProcess(
   environment ??= <String, String>{};
   environment['BOT'] = isBot ? 'true' : 'false';
   final Process process = await _processManager.start(
-    <String>[executable]..addAll(arguments),
+    <String>[executable, ...arguments],
     environment: environment,
     workingDirectory: workingDirectory ?? cwd,
   );

dev/devicelab/lib/tasks/hot_mode_tests.dart

@@ -39,7 +39,7 @@ TaskFunction createHotModeTest() {
         {
           final Process process = await startProcess(
               path.join(flutterDirectory.path, 'bin', 'flutter'),
-              <String>['run']..addAll(options),
+              <String>['run', ...options],
               environment: null,
           );
 
@@ -93,7 +93,7 @@ TaskFunction createHotModeTest() {
         {
           final Process process = await startProcess(
               path.join(flutterDirectory.path, 'bin', 'flutter'),
-              <String>['run']..addAll(options),
+              <String>['run', ...options],
               environment: null,
           );
           final Completer<void> stdoutDone = Completer<void>();

dev/devicelab/lib/tasks/microbenchmarks.dart

@@ -65,7 +65,7 @@ Future<Process> _startFlutter({
   bool canFail = false,
   Map<String, String> environment,
 }) {
-  final List<String> args = <String>['run']..addAll(options);
+  final List<String> args = <String>['run', ...options];
   return startProcess(path.join(flutterDirectory.path, 'bin', 'flutter'), args, environment: environment);
 }
 

dev/devicelab/lib/tasks/plugin_tests.dart

@@ -65,7 +65,7 @@ class FlutterProject {
     await inDirectory(directory, () async {
       await flutter(
         'create',
-        options: <String>['--template=app', '--org', 'io.flutter.devicelab']..addAll(options)..add('plugintest'),
+        options: <String>['--template=app', '--org', 'io.flutter.devicelab', ...options, 'plugintest'],
       );
     });
     return FlutterProject(directory, 'plugintest');

dev/devicelab/lib/tasks/run_without_leak.dart

@@ -24,7 +24,7 @@ TaskFunction createRunWithoutLeakTest(dynamic dir) {
     await inDirectory<void>(dir, () async {
       final Process process = await startProcess(
           path.join(flutterDirectory.path, 'bin', 'flutter'),
-          <String>['run']..addAll(options),
+          <String>['run', ...options],
           environment: null,
       );
       final Completer<void> stdoutDone = Completer<void>();

dev/devicelab/lib/tasks/web_dev_mode_tests.dart

@@ -37,7 +37,7 @@ TaskFunction createWebDevModeTest() {
           await packagesGet.exitCode;
           final Process process = await startProcess(
               path.join(flutterDirectory.path, 'bin', 'flutter'),
-              <String>['run']..addAll(options),
+              <String>['run', ...options],
               environment: <String, String>{
                 'FLUTTER_WEB': 'true',
               },
@@ -96,7 +96,7 @@ TaskFunction createWebDevModeTest() {
         {
           final Process process = await startProcess(
               path.join(flutterDirectory.path, 'bin', 'flutter'),
-              <String>['run']..addAll(options),
+              <String>['run', ...options],
               environment: <String, String>{
                 'FLUTTER_WEB': 'true',
               },

dev/devicelab/test/run_test.dart

@@ -21,7 +21,7 @@ void main() {
       }
       final String dart = path.absolute(path.join('..', '..', 'bin', 'cache', 'dart-sdk', 'bin', 'dart'));
       final ProcessResult scriptProcess = processManager.runSync(
-        <String>[dart]..addAll(options)
+        <String>[dart, ...options]
       );
       return scriptProcess;
     }

dev/snippets/lib/snippets.dart

@@ -175,7 +175,8 @@ class SnippetGenerator {
     }
     return <_ComponentTuple>[
       _ComponentTuple('description', description),
-    ]..addAll(components);
+      ...components,
+    ];
   }
 
   String _loadFileAsUtf8(File file) {

dev/snippets/pubspec.yaml

@@ -6,7 +6,7 @@ homepage: https://github.com/flutter/flutter
 
 environment:
   # The pub client defaults to an <2.0.0 sdk constraint which we need to explicitly overwrite.
-  sdk: ">=2.0.0-dev.68.0 <3.0.0"
+  sdk: ">=2.2.2 <3.0.0"
 
 dartdoc:
   # Exclude this package from the hosted API docs (Ironically...).

dev/tools/dartdoc.dart

@@ -117,7 +117,7 @@ Future<void> main(List<String> arguments) async {
   // Verify which version of dartdoc we're using.
   final ProcessResult result = Process.runSync(
     pubExecutable,
-    <String>[]..addAll(dartdocBaseArgs)..add('--version'),
+    <String>[...dartdocBaseArgs, '--version'],
     workingDirectory: kDocsRoot,
     environment: pubEnvironment,
   );
@@ -137,7 +137,8 @@ Future<void> main(List<String> arguments) async {
   // Generate the documentation.
   // We don't need to exclude flutter_tools in this list because it's not in the
   // recursive dependencies of the package defined at dev/docs/pubspec.yaml
-  final List<String> dartdocArgs = <String>[]..addAll(dartdocBaseArgs)..addAll(<String>[
+  final List<String> dartdocArgs = <String>[
+    ...dartdocBaseArgs,
     '--inject-html',
     '--header', 'styles.html',
     '--header', 'analytics.html',
@@ -145,7 +146,8 @@ Future<void> main(List<String> arguments) async {
     '--header', 'snippets.html',
     '--header', 'opensearch.html',
     '--footer-text', 'lib/footer.html',
-    '--allow-warnings-in-packages', <String>[
+    '--allow-warnings-in-packages',
+    <String>[
       'Flutter',
       'flutter',
       'platform_integration',
@@ -198,7 +200,7 @@ Future<void> main(List<String> arguments) async {
     '--favicon=favicon.ico',
     '--package-order', 'flutter,Dart,platform_integration,flutter_test,flutter_driver',
     '--auto-include-dependencies',
-  ]);
+  ];
 
   String quote(String arg) => arg.contains(' ') ? "'$arg'" : arg;
   print('Executing: (cd $kDocsRoot ; $pubExecutable ${dartdocArgs.map<String>(quote).join(' ')})');

dev/tools/pubspec.yaml

@@ -3,7 +3,7 @@ description: Various repository development tools for flutter.
 
 environment:
   # The pub client defaults to an <2.0.0 sdk constraint which we need to explicitly overwrite.
-  sdk: ">=2.2.0 <3.0.0"
+  sdk: ">=2.2.2 <3.0.0"
 
 dependencies:
   archive: 2.0.10

examples/flutter_gallery/lib/demo/cupertino/cupertino_navigation_demo.dart

@@ -434,7 +434,8 @@ class CupertinoDemoTab2 extends StatelessWidget {
         child: ListView(
           children: <Widget>[
             Tab2Header(),
-          ]..addAll(buildTab2Conversation()),
+            ...buildTab2Conversation(),
+          ],
         ),
       ),
     );

examples/flutter_gallery/lib/demo/pesto_demo.dart

@@ -493,11 +493,9 @@ class RecipeSheet extends StatelessWidget {
                   ),
                 ]
               ),
-            ]..addAll(recipe.ingredients.map<TableRow>(
-              (RecipeIngredient ingredient) {
+              ...recipe.ingredients.map<TableRow>((RecipeIngredient ingredient) {
                 return _buildItemRow(ingredient.amount, ingredient.description);
-              }
-            ))..add(
+              }),
               TableRow(
                 children: <Widget>[
                   const SizedBox(),
@@ -506,12 +504,11 @@ class RecipeSheet extends StatelessWidget {
                     child: Text('Steps', style: headingStyle),
                   ),
                 ]
-              )
-            )..addAll(recipe.steps.map<TableRow>(
-              (RecipeStep step) {
+              ),
+              ...recipe.steps.map<TableRow>((RecipeStep step) {
                 return _buildItemRow(step.duration ?? '', step.description);
-              }
-            )),
+              }),
+            ],
           ),
         ),
       ),

examples/flutter_gallery/lib/gallery/options.dart

@@ -455,18 +455,14 @@ class GalleryOptionsPage extends StatelessWidget {
           const Divider(),
           const _Heading('Platform mechanics'),
           _PlatformItem(options, onOptionsChanged),
-        ]..addAll(
-          _enabledDiagnosticItems(),
-        )..addAll(
-          <Widget>[
-            const Divider(),
-            const _Heading('Flutter gallery'),
-            _ActionItem('About Flutter Gallery', () {
-              showGalleryAboutDialog(context);
-            }),
-            _ActionItem('Send feedback', onSendFeedback),
-          ],
-        ),
+          ..._enabledDiagnosticItems(),
+          const Divider(),
+          const _Heading('Flutter gallery'),
+          _ActionItem('About Flutter Gallery', () {
+            showGalleryAboutDialog(context);
+          }),
+          _ActionItem('Send feedback', onSendFeedback),
+        ],
       ),
     );
   }

examples/flutter_gallery/pubspec.yaml

@@ -2,7 +2,7 @@ name: flutter_gallery
 
 environment:
   # The pub client defaults to an <2.0.0 sdk constraint which we need to explicitly overwrite.
-  sdk: ">=2.2.0 <3.0.0"
+  sdk: ">=2.2.2 <3.0.0"
 
 dependencies:
   flutter:

packages/flutter/lib/src/rendering/box.dart

@@ -2010,13 +2010,13 @@ abstract class RenderBox extends RenderObject {
           // TODO(jacobr): consider nesting the failures object so it is collapsible.
           throw FlutterError.fromParts(<DiagnosticsNode>[
             ErrorSummary('The intrinsic dimension methods of the $runtimeType class returned values that violate the intrinsic protocol contract.'),
-            ErrorDescription('The following ${failures.length > 1 ? "failures" : "failure"} was detected:') // should this be tagged as an error or not?
-          ]..addAll(failures)
-           ..add(ErrorHint(
+            ErrorDescription('The following ${failures.length > 1 ? "failures" : "failure"} was detected:'), // should this be tagged as an error or not?
+            ...failures,
+            ErrorHint(
               'If you are not writing your own RenderBox subclass, then this is not\n'
               'your fault. Contact support: https://github.com/flutter/flutter/issues/new?template=BUG.md'
-            ))
-          );
+            ),
+          ]);
         }
       }
       return true;

packages/flutter/lib/src/rendering/flex.dart

@@ -708,12 +708,13 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
               '  http://api.flutter.dev/flutter/rendering/debugDumpRenderTree.html'
             ),
             describeForError('The affected RenderFlex is', style: DiagnosticsTreeStyle.errorProperty),
-            DiagnosticsProperty<dynamic>('The creator information is set to', debugCreator, style: DiagnosticsTreeStyle.errorProperty)
-          ]..addAll(addendum)
-           ..add(ErrorDescription(
-             'If none of the above helps enough to fix this problem, please don\'t hesitate to file a bug:\n'
-             '  https://github.com/flutter/flutter/issues/new?template=BUG.md'
-          )));
+            DiagnosticsProperty<dynamic>('The creator information is set to', debugCreator, style: DiagnosticsTreeStyle.errorProperty),
+            ...addendum,
+            ErrorDescription(
+              'If none of the above helps enough to fix this problem, please don\'t hesitate to file a bug:\n'
+              '  https://github.com/flutter/flutter/issues/new?template=BUG.md'
+            )
+          ]);
         }());
         totalFlex += childParentData.flex;
         lastFlexChild = child;

packages/flutter/lib/src/rendering/sliver.dart

@@ -1204,15 +1204,16 @@ abstract class RenderSliver extends RenderObject {
       if (geometry.paintExtent > constraints.remainingPaintExtent) {
         throw FlutterError.fromParts(<DiagnosticsNode>[
           ErrorSummary('SliverGeometry has a paintOffset that exceeds the remainingPaintExtent from the constraints.'),
-          describeForError('The render object whose geometry violates the constraints is the following')
-        ]..addAll(_debugCompareFloats(
+          describeForError('The render object whose geometry violates the constraints is the following'),
+          ..._debugCompareFloats(
             'remainingPaintExtent', constraints.remainingPaintExtent,
             'paintExtent', geometry.paintExtent,
-        ))
-        ..add(ErrorDescription(
-          'The paintExtent must cause the child sliver to paint within the viewport, and so '
-          'cannot exceed the remainingPaintExtent.',
-        )));
+          ),
+          ErrorDescription(
+            'The paintExtent must cause the child sliver to paint within the viewport, and so '
+            'cannot exceed the remainingPaintExtent.',
+          ),
+        ]);
       }
       return true;
     }());

packages/flutter/lib/src/widgets/editable_text.dart

@@ -344,10 +344,10 @@ class EditableText extends StatefulWidget {
        _strutStyle = strutStyle,
        keyboardType = keyboardType ?? (maxLines == 1 ? TextInputType.text : TextInputType.multiline),
        inputFormatters = maxLines == 1
-           ? (
-               <TextInputFormatter>[BlacklistingTextInputFormatter.singleLineFormatter]
-                 ..addAll(inputFormatters ?? const Iterable<TextInputFormatter>.empty())
-             )
+           ? <TextInputFormatter>[
+               BlacklistingTextInputFormatter.singleLineFormatter,
+               ...inputFormatters ?? const Iterable<TextInputFormatter>.empty(),
+             ]
            : inputFormatters,
        showCursor = showCursor ?? !readOnly,
        super(key: key);

packages/flutter/test/services/message_codecs_test.dart

@@ -122,22 +122,22 @@ void main() {
       _checkEncoding<dynamic>(
         standard,
         Uint8List(253),
-        <int>[8, 253]..addAll(List<int>.filled(253, 0)),
+        <int>[8, 253, ...List<int>.filled(253, 0)],
       );
       _checkEncoding<dynamic>(
         standard,
         Uint8List(254),
-        <int>[8, 254, 254, 0]..addAll(List<int>.filled(254, 0)),
+        <int>[8, 254, 254, 0, ...List<int>.filled(254, 0)],
       );
       _checkEncoding<dynamic>(
         standard,
         Uint8List(0xffff),
-        <int>[8, 254, 0xff, 0xff]..addAll(List<int>.filled(0xffff, 0)),
+        <int>[8, 254, 0xff, 0xff, ...List<int>.filled(0xffff, 0)],
       );
       _checkEncoding<dynamic>(
         standard,
         Uint8List(0xffff + 1),
-        <int>[8, 255, 0, 0, 1, 0]..addAll(List<int>.filled(0xffff + 1, 0)),
+        <int>[8, 255, 0, 0, 1, 0, ...List<int>.filled(0xffff + 1, 0)],
       );
     });
     test('should encode and decode simple messages', () {

packages/flutter/test/widgets/scrollable_semantics_test.dart

@@ -196,7 +196,8 @@ void main() {
                       title: Text('App Bar'),
                     ),
                   ),
-                ]..addAll(slivers),
+                  ...slivers,
+                ],
               );
             },
           ),

packages/flutter/test/widgets/scrollbar_test.dart

@@ -113,16 +113,17 @@ void main() {
         scrollMetrics: defaultMetrics,
       );
 
-      final List<ScrollMetrics> metricsList =
-        <ScrollMetrics> [startingMetrics.copyWith(pixels: 0.01)]
-        ..addAll(List<ScrollMetrics>.generate(
-            (maxExtent/viewportDimension).round(),
-            (int index) => startingMetrics.copyWith(pixels: (index + 1) * viewportDimension),
-          ).where((ScrollMetrics metrics) => !metrics.outOfRange))
-        ..add(startingMetrics.copyWith(pixels: maxExtent - 0.01));
+      final List<ScrollMetrics> metricsList = <ScrollMetrics> [
+        startingMetrics.copyWith(pixels: 0.01),
+        ...List<ScrollMetrics>.generate(
+          (maxExtent / viewportDimension).round(),
+          (int index) => startingMetrics.copyWith(pixels: (index + 1) * viewportDimension),
+        ).where((ScrollMetrics metrics) => !metrics.outOfRange),
+        startingMetrics.copyWith(pixels: maxExtent - 0.01),
+      ];
 
       double lastCoefficient;
-      for(ScrollMetrics metrics in metricsList) {
+      for (ScrollMetrics metrics in metricsList) {
         painter.update(metrics, metrics.axisDirection);
         painter.paint(testCanvas, size);
 

packages/flutter/test/widgets/sliver_semantics_test.dart

@@ -599,7 +599,8 @@ void _tests() {
                   expandedHeight: 100.0,
                   title: Text('AppBar'),
                 ),
-              ]..addAll(slivers),
+                ...slivers,
+              ],
             ),
           ),
         ),
@@ -824,7 +825,8 @@ void _tests() {
                   expandedHeight: 100.0,
                   title: Text('AppBar'),
                 ),
-              ]..addAll(slivers),
+                ...slivers,
+              ],
             ),
           ),
         ),

packages/flutter_tools/lib/src/android/android_device.dart

@@ -219,7 +219,7 @@ class AndroidDevice extends Device {
   _AndroidDevicePortForwarder _portForwarder;
 
   List<String> adbCommandForDevice(List<String> args) {
-    return <String>[getAdbPath(androidSdk), '-s', id]..addAll(args);
+    return <String>[getAdbPath(androidSdk), '-s', id, ...args];
   }
 
   String runAdbCheckedSync(

packages/flutter_tools/lib/src/asset.dart

@@ -458,7 +458,7 @@ List<Font> _parsePackageFonts(
         ));
       } else {
         packageFontAssets.add(FontAsset(
-          Uri(pathSegments: <String>['packages', packageName]..addAll(assetUri.pathSegments)),
+          Uri(pathSegments: <String>['packages', packageName, ...assetUri.pathSegments]),
           weight: fontAsset.weight,
           style: fontAsset.style,
         ));
@@ -677,7 +677,7 @@ _Asset _resolveAsset(
     baseDir: assetsBaseDir,
     entryUri: packageName == null
         ? assetUri // Asset from the current application.
-        : Uri(pathSegments: <String>['packages', packageName]..addAll(assetUri.pathSegments)), // Asset from, and declared in $packageName.
+        : Uri(pathSegments: <String>['packages', packageName, ...assetUri.pathSegments]), // Asset from, and declared in $packageName.
     relativeUri: assetUri,
   );
 }

packages/flutter_tools/lib/src/base/build.dart

@@ -51,7 +51,8 @@ class GenSnapshot {
   }) {
     final List<String> args = <String>[
       '--causal_async_stacks',
-    ]..addAll(additionalArgs);
+      ...additionalArgs,
+    ];
 
     final String snapshotterPath = getSnapshotterPath(snapshotType);
 
@@ -61,7 +62,7 @@ class GenSnapshot {
     // architecture.
     if (snapshotType.platform == TargetPlatform.ios) {
       final String hostArch = iosArch == IOSArch.armv7 ? '-i386' : '-x86_64';
-      return runCommandAndStreamOutput(<String>['/usr/bin/arch', hostArch, snapshotterPath]..addAll(args));
+      return runCommandAndStreamOutput(<String>['/usr/bin/arch', hostArch, snapshotterPath, ...args]);
     }
 
     StringConverter outputFilter;
@@ -72,8 +73,7 @@ class GenSnapshot {
       outputFilter = (String line) => line != kStripWarning ? line : null;
     }
 
-    return runCommandAndStreamOutput(<String>[snapshotterPath]..addAll(args),
-                                     mapFunction: outputFilter);
+    return runCommandAndStreamOutput(<String>[snapshotterPath, ...args], mapFunction: outputFilter);
   }
 }
 
@@ -168,7 +168,7 @@ class AOTSnapshotter {
     // If inputs and outputs have not changed since last run, skip the build.
     final Fingerprinter fingerprinter = Fingerprinter(
       fingerprintPath: '$depfilePath.fingerprint',
-      paths: <String>[mainPath]..addAll(inputPaths)..addAll(outputPaths),
+      paths: <String>[mainPath, ...inputPaths, ...outputPaths],
       properties: <String, String>{
         'buildMode': buildMode.toString(),
         'targetPlatform': platform.toString(),
@@ -422,7 +422,7 @@ class JITSnapshotter {
     // If inputs and outputs have not changed since last run, skip the build.
     final Fingerprinter fingerprinter = Fingerprinter(
       fingerprintPath: '$depfilePath.fingerprint',
-      paths: <String>[mainPath]..addAll(inputPaths)..addAll(outputPaths),
+      paths: <String>[mainPath, ...inputPaths, ...outputPaths],
       properties: <String, String>{
         'buildMode': buildMode.toString(),
         'targetPlatform': platform.toString(),

packages/flutter_tools/lib/src/cache.dart

@@ -923,7 +923,7 @@ String _flattenNameNoSubdirs(String fileName) {
 
 @visibleForTesting
 String flattenNameSubdirs(Uri url) {
-  final List<String> pieces = <String>[url.host]..addAll(url.pathSegments);
+  final List<String> pieces = <String>[url.host, ...url.pathSegments];
   final Iterable<String> convertedPieces = pieces.map<String>(_flattenNameNoSubdirs);
   return fs.path.joinAll(convertedPieces);
 }

packages/flutter_tools/lib/src/commands/build_aot.dart

@@ -127,10 +127,13 @@ class BuildAotCommand extends BuildSubCommand with TargetPlatformBasedDevelopmen
         if ((await Future.wait<int>(exitCodes.values)).every((int buildExitCode) => buildExitCode == 0)) {
           final Iterable<String> dylibs = iosBuilds.values.map<String>((String outputDir) => fs.path.join(outputDir, 'App.framework', 'App'));
           fs.directory(fs.path.join(outputPath, 'App.framework'))..createSync();
-          await runCheckedAsync(<String>['lipo']
-            ..addAll(dylibs)
-            ..addAll(<String>['-create', '-output', fs.path.join(outputPath, 'App.framework', 'App')]),
-          );
+          await runCheckedAsync(<String>[
+            'lipo',
+            ...dylibs,
+            '-create',
+            '-output',
+            fs.path.join(outputPath, 'App.framework', 'App'),
+          ]);
         } else {
           status?.cancel();
           exitCodes.forEach((IOSArch iosArch, Future<int> exitCodeFuture) async {

packages/flutter_tools/lib/src/commands/drive.dart

@@ -182,7 +182,7 @@ class DriveCommand extends RunCommandBase {
     // if the application is `lib/foo/bar.dart`, the test file is expected to
     // be `test_driver/foo/bar_test.dart`.
     final String pathWithNoExtension = fs.path.withoutExtension(fs.path.joinAll(
-      <String>[packageDir, 'test_driver']..addAll(parts.skip(1))));
+      <String>[packageDir, 'test_driver', ...parts.skip(1)]));
     return '${pathWithNoExtension}_test${fs.path.extension(appFile)}';
   }
 }
@@ -297,13 +297,13 @@ Future<void> _runTests(List<String> testArgs, String observatoryUri) async {
   PackageMap.globalPackagesPath = fs.path.normalize(fs.path.absolute(PackageMap.globalPackagesPath));
   final String dartVmPath = fs.path.join(dartSdkPath, 'bin', 'dart');
   final int result = await runCommandAndStreamOutput(
-    <String>[dartVmPath]
-      ..addAll(dartVmFlags)
-      ..addAll(testArgs)
-      ..addAll(<String>[
-        '--packages=${PackageMap.globalPackagesPath}',
-        '-rexpanded',
-      ]),
+    <String>[
+      dartVmPath,
+      ...dartVmFlags,
+      ...testArgs,
+      '--packages=${PackageMap.globalPackagesPath}',
+      '-rexpanded',
+    ],
     environment: <String, String>{'VM_SERVICE_URL': observatoryUri},
   );
   if (result != 0)

packages/flutter_tools/lib/src/commands/packages.dart

@@ -163,7 +163,7 @@ class PackagesTestCommand extends FlutterCommand {
 
   @override
   Future<FlutterCommandResult> runCommand() async {
-    await pub(<String>['run', 'test']..addAll(argResults.rest), context: PubContext.runTest, retry: false);
+    await pub(<String>['run', 'test', ...argResults.rest], context: PubContext.runTest, retry: false);
     return null;
   }
 }
@@ -193,7 +193,7 @@ class PackagesForwardCommand extends FlutterCommand {
 
   @override
   Future<FlutterCommandResult> runCommand() async {
-    await pub(<String>[_commandName]..addAll(argResults.rest), context: PubContext.pubForward, retry: false);
+    await pub(<String>[_commandName, ...argResults.rest], context: PubContext.pubForward, retry: false);
     return null;
   }
 

packages/flutter_tools/lib/src/dart/pub.dart

@@ -192,7 +192,7 @@ Future<void> pubInteractively(
 
 /// The command used for running pub.
 List<String> _pubCommand(List<String> arguments) {
-  return <String>[ sdkBinaryName('pub') ]..addAll(arguments);
+  return <String>[sdkBinaryName('pub'), ...arguments];
 }
 
 /// The full environment used when running pub.

packages/flutter_tools/lib/src/fuchsia/fuchsia_kernel_compiler.dart

@@ -84,9 +84,10 @@ class FuchsiaKernelCompiler {
     ];
 
     final List<String> command = <String>[
-          artifacts.getArtifactPath(Artifact.engineDartBinary),
-          fuchsiaArtifacts.kernelCompiler.path,
-        ]..addAll(flags);
+      artifacts.getArtifactPath(Artifact.engineDartBinary),
+      fuchsiaArtifacts.kernelCompiler.path,
+      ...flags,
+    ];
     final Process process = await runCommand(command);
     final Status status = logger.startProgress(
       'Building Fuchsia application...',

packages/flutter_tools/lib/src/macos/xcode.dart

@@ -90,11 +90,11 @@ class Xcode {
   }
 
   Future<RunResult> cc(List<String> args) {
-    return runCheckedAsync(<String>['xcrun', 'cc']..addAll(args));
+    return runCheckedAsync(<String>['xcrun', 'cc', ...args]);
   }
 
   Future<RunResult> clang(List<String> args) {
-    return runCheckedAsync(<String>['xcrun', 'clang']..addAll(args));
+    return runCheckedAsync(<String>['xcrun', 'clang', ...args]);
   }
 
   String getSimulatorPath() {

packages/flutter_tools/test/base/flags_test.dart

@@ -17,7 +17,7 @@ void main() {
   Cache.disableLocking();
 
   Future<void> runCommand(Iterable<String> flags, _TestMethod testMethod) async {
-    final List<String> args = <String>['test']..addAll(flags);
+    final List<String> args = <String>['test', ...flags];
     final _TestCommand command = _TestCommand(testMethod);
     await createTestCommandRunner(command).run(args);
   }

packages/flutter_tools/test/commands/create_test.dart

@@ -1169,10 +1169,11 @@ Future<void> _analyzeProject(String workingDir) async {
     'flutter_tools.dart',
   ));
 
-  final List<String> args = <String>[]
-    ..addAll(dartVmFlags)
-    ..add(flutterToolsPath)
-    ..add('analyze');
+  final List<String> args = <String>[
+    ...dartVmFlags,
+    flutterToolsPath,
+    'analyze',
+  ];
 
   final ProcessResult exec = await Process.run(
     '$dartSdkPath/bin/dart',
@@ -1196,21 +1197,22 @@ Future<void> _runFlutterTest(Directory workingDir, { String target }) async {
   // files anymore.
   await Process.run(
     '$dartSdkPath/bin/dart',
-    <String>[]
-    ..addAll(dartVmFlags)
-    ..add(flutterToolsPath)
-    ..addAll(<String>['packages', 'get']),
+    <String>[
+      ...dartVmFlags,
+      flutterToolsPath,
+      'packages',
+      'get',
+    ],
     workingDirectory: workingDir.path,
   );
 
-  final List<String> args = <String>[]
-    ..addAll(dartVmFlags)
-    ..add(flutterToolsPath)
-    ..add('test')
-    ..add('--no-color');
-  if (target != null) {
-    args.add(target);
-  }
+  final List<String> args = <String>[
+    ...dartVmFlags,
+    flutterToolsPath,
+    'test',
+    '--no-color',
+    if (target != null) target,
+  ];
 
   final ProcessResult exec = await Process.run(
     '$dartSdkPath/bin/dart',

packages/flutter_tools/test/commands/test_test.dart

@@ -172,13 +172,14 @@ Future<ProcessResult> _runFlutterTest(
   if (!testFile.existsSync())
     fail('missing test file: $testFile');
 
-  final List<String> args = <String>[]
-    ..addAll(dartVmFlags)
-    ..add(fs.path.absolute(fs.path.join('bin', 'flutter_tools.dart')))
-    ..add('test')
-    ..add('--no-color')
-    ..addAll(extraArgs)
-    ..add(testFilePath);
+  final List<String> args = <String>[
+    ...dartVmFlags,
+    fs.path.absolute(fs.path.join('bin', 'flutter_tools.dart')),
+    'test',
+    '--no-color',
+    ...extraArgs,
+    testFilePath
+  ];
 
   while (_testExclusionLock != null)
     await _testExclusionLock;

packages/flutter_tools/test/src/common.dart

@@ -131,7 +131,7 @@ Future<String> createProject(Directory temp, { List<String> arguments }) async {
   final String projectPath = fs.path.join(temp.path, 'flutter_project');
   final CreateCommand command = CreateCommand();
   final CommandRunner<void> runner = createTestCommandRunner(command);
-  await runner.run(<String>['create']..addAll(arguments)..add(projectPath));
+  await runner.run(<String>['create', ...arguments, projectPath]);
   return projectPath;
 }