Merge pull request #709 from sass/analysis

Enable stricter analysis options, especially around typing

.travis.yml

@@ -92,7 +92,7 @@ jobs:
   # Miscellaneous checks.
   - name: static analysis
     language: dart
-    dart_task: {dartanalyzer: --fatal-warnings lib tool test}
+    dart_task: {dartanalyzer: --fatal-warnings --fatal-infos lib tool test}
   - name: code formatting
     language: dart
     dart_task: dartfmt

analysis_options.yaml

@@ -1,5 +1,17 @@
 analyzer:
   strong-mode:
     implicit-casts: false
+  language:
+    strict-inference: true
+    strict-raw-types: true
   errors:
     missing_js_lib_annotation: ignore
+    deprecated_member_use_from_same_package: ignore
+
+    # These are necessary for matching the JS API.
+    avoid_types_as_parameter_names: ignore
+
+    # This has tons of false positives for StreamSubscription.close().
+    unawaited_futures: ignore
+
+include: package:pedantic/analysis_options.yaml

lib/src/ast/sass/interpolation.dart

@@ -13,7 +13,7 @@ class Interpolation implements SassNode {
   ///
   /// This contains [String]s and [Expression]s. It never contains two adjacent
   /// [String]s.
-  final List contents;
+  final List<Object /* String | Expression */ > contents;
 
   final FileSpan span;
 
@@ -33,7 +33,7 @@ class Interpolation implements SassNode {
     return first is String ? first : '';
   }
 
-  Interpolation(Iterable /*(String|Expression)*/ contents, this.span)
+  Interpolation(Iterable<Object /* String | Expression */ > contents, this.span)
       : contents = List.unmodifiable(contents) {
     for (var i = 0; i < this.contents.length; i++) {
       if (this.contents[i] is! String && this.contents[i] is! Expression) {

lib/src/async_environment.dart

@@ -505,8 +505,8 @@ class AsyncEnvironment {
   }
 
   /// Sets [content] as [this.content] for the duration of [callback].
-  Future withContent(
-      UserDefinedCallable<AsyncEnvironment> content, Future callback()) async {
+  Future<void> withContent(UserDefinedCallable<AsyncEnvironment> content,
+      Future<void> callback()) async {
     var oldContent = _content;
     _content = content;
     await callback();
@@ -514,7 +514,7 @@ class AsyncEnvironment {
   }
 
   /// Sets [inMixin] to `true` for the duration of [callback].
-  Future asMixin(Future callback()) async {
+  Future<void> asMixin(Future<void> callback()) async {
     var oldInMixin = _inMixin;
     _inMixin = true;
     await callback();

lib/src/callable/async.dart

@@ -35,6 +35,6 @@ abstract class AsyncCallable {
       AsyncBuiltInCallable(name, arguments, (arguments) {
         var result = callback(arguments);
         if (result is ext.Value) return result as Value;
-        return (result as Future).then((value) => value as Value);
+        return (result as Future<ext.Value>).then((value) => value as Value);
       });
 }

lib/src/environment.dart

@@ -5,7 +5,7 @@
 // DO NOT EDIT. This file was generated from async_environment.dart.
 // See tool/grind/synchronize.dart for details.
 //
-// Checksum: 3210a5c0528eac456ae8ca7827b65f3976f6b29d
+// Checksum: 23c920bd76d38c4ccf2024a0740aeae9672143d0
 //
 // ignore_for_file: unused_import
 

lib/src/executable/compile_stylesheet.dart

@@ -30,7 +30,7 @@ import 'options.dart';
 /// If [ifModified] is `true`, only recompiles if [source]'s modification time
 /// or that of a file it imports is more recent than [destination]'s
 /// modification time. Note that these modification times are cached by [graph].
-Future compileStylesheet(ExecutableOptions options, StylesheetGraph graph,
+Future<void> compileStylesheet(ExecutableOptions options, StylesheetGraph graph,
     String source, String destination,
     {bool ifModified = false}) async {
   var importer = FilesystemImporter('.');

lib/src/executable/options.dart

@@ -253,7 +253,7 @@ class ExecutableOptions {
           (!_isWindowsPath(argument, 0) ||
               // Look for colons after index 1, since that's where the drive
               // letter is on Windows paths.
-              argument.indexOf(":", 2) != -1)) {
+              argument.contains(":", 2))) {
         colonArgs = true;
       } else if (dirExists(argument)) {
         directories.add(argument);

lib/src/executable/repl.dart

@@ -16,7 +16,7 @@ import '../value.dart' as internal;
 import '../visitor/evaluate.dart';
 
 /// Runs an interactive SassScript shell according to [options].
-Future repl(ExecutableOptions options) async {
+Future<void> repl(ExecutableOptions options) async {
   var repl = Repl(prompt: '>> ');
   var variables = <String, internal.Value>{};
   await for (String line in repl.runAsync()) {

lib/src/executable/watch.dart

@@ -19,7 +19,7 @@ import 'compile_stylesheet.dart';
 import 'options.dart';
 
 /// Watches all the files in [graph] for changes and updates them as necessary.
-Future watch(ExecutableOptions options, StylesheetGraph graph) async {
+Future<void> watch(ExecutableOptions options, StylesheetGraph graph) async {
   var directoriesToWatch = [
     ...options.sourceDirectoriesToDestinations.keys,
     ...options.sourcesToDestinations.keys.map(p.dirname),
@@ -30,7 +30,9 @@ Future watch(ExecutableOptions options, StylesheetGraph graph) async {
   await Future.wait(directoriesToWatch.map((dir) {
     // If a directory doesn't exist, watch its parent directory so that we're
     // notified once it starts existing.
-    while (!dirExists(dir)) dir = p.dirname(dir);
+    while (!dirExists(dir)) {
+      dir = p.dirname(dir);
+    }
     return dirWatcher.watch(dir);
   }));
 
@@ -117,7 +119,7 @@ class _Watcher {
   /// Listens to `watcher.events` and updates the filesystem accordingly.
   ///
   /// Returns a future that will only complete if an unexpected error occurs.
-  Future watch(MultiDirWatcher watcher) async {
+  Future<void> watch(MultiDirWatcher watcher) async {
     await for (var event in _debounceEvents(watcher.events)) {
       var extension = p.extension(event.path);
       if (extension != '.sass' && extension != '.scss') continue;
@@ -226,7 +228,7 @@ class _Watcher {
     var toRecompile = Queue.of(nodes);
 
     var allSucceeded = true;
-    while (!toRecompile.isEmpty) {
+    while (toRecompile.isNotEmpty) {
       var node = toRecompile.removeFirst();
       if (!seen.add(node)) continue;
 

lib/src/extend/extension.dart

@@ -76,8 +76,9 @@ class Extension {
   /// query context for this extender.
   void assertCompatibleMediaContext(List<CssMediaQuery> mediaContext) {
     if (this.mediaContext == null) return;
-    if (mediaContext != null && listEquals(this.mediaContext, mediaContext))
+    if (mediaContext != null && listEquals(this.mediaContext, mediaContext)) {
       return;
+    }
 
     throw SassException(
         "You may not @extend selectors across media queries.", span);

lib/src/importer/node/implementation.dart

@@ -48,9 +48,10 @@ class NodeImporter {
   /// The importer functions passed in by the user.
   final List<JSFunction> _importers;
 
-  NodeImporter(this._context, Iterable<String> includePaths, Iterable importers)
+  NodeImporter(
+      this._context, Iterable<String> includePaths, Iterable<Object> importers)
       : _includePaths = List.unmodifiable(_addSassPath(includePaths)),
-        _importers = List.unmodifiable(importers);
+        _importers = List.unmodifiable(importers.cast());
 
   /// Returns [includePaths] followed by any paths loaded from the `SASS_PATH`
   /// environment variable.
@@ -184,7 +185,7 @@ class NodeImporter {
   /// Calls an importer that may or may not be asynchronous.
   Future<Object> _callImporterAsync(
       JSFunction importer, String url, String previousString) async {
-    var completer = Completer();
+    var completer = Completer<Object>();
 
     var result = call3(importer, _context, url, previousString,
         allowInterop(completer.complete));

lib/src/importer/node/interface.dart

@@ -7,8 +7,8 @@ import 'dart:async';
 import 'package:tuple/tuple.dart';
 
 class NodeImporter {
-  NodeImporter(
-      Object context, Iterable<String> includePaths, Iterable importers);
+  NodeImporter(Object context, Iterable<String> includePaths,
+      Iterable<Object> importers);
 
   Tuple2<String, String> load(String url, Uri previous) => null;
 

lib/src/interpolation_buffer.dart

@@ -48,7 +48,7 @@ class InterpolationBuffer implements StringSink {
   void addInterpolation(Interpolation interpolation) {
     if (interpolation.contents.isEmpty) return;
 
-    Iterable toAdd = interpolation.contents;
+    Iterable<Object> toAdd = interpolation.contents;
     var first = interpolation.contents.first;
     if (first is String) {
       _text.write(first);

lib/src/io/node.dart

@@ -22,7 +22,7 @@ class _FS {
   external void mkdirSync(String path);
   external _Stat statSync(String path);
   external void unlinkSync(String path);
-  external List readdirSync(String path);
+  external List<Object> readdirSync(String path);
 }
 
 @JS()

lib/src/node.dart

@@ -40,7 +40,7 @@ import 'visitor/serialize.dart';
 /// to run the executable when installed from npm.
 void main() {
   exports.run_ =
-      allowInterop((args) => executable.main(List.from(args as List)));
+      allowInterop((args) => executable.main(List.from(args as List<Object>)));
   exports.render = allowInterop(_render);
   exports.renderSync = allowInterop(_renderSync);
   exports.info =
@@ -225,7 +225,7 @@ List<AsyncCallable> _parseFunctions(RenderOptions options,
     } else {
       result.add(AsyncBuiltInCallable.parsed(tuple.item1, tuple.item2,
           (arguments) async {
-        var completer = Completer();
+        var completer = Completer<Object>();
         var jsArguments = [
           ...arguments.map(wrapValue),
           allowInterop(([result]) => completer.complete(result))
@@ -245,8 +245,8 @@ NodeImporter _parseImporter(RenderOptions options, DateTime start) {
   List<JSFunction> importers;
   if (options.importer == null) {
     importers = [];
-  } else if (options.importer is List) {
-    importers = (options.importer as List).cast();
+  } else if (options.importer is List<Object>) {
+    importers = (options.importer as List<Object>).cast();
   } else {
     importers = [options.importer as JSFunction];
   }

lib/src/node/function.dart

@@ -12,5 +12,5 @@ class JSFunction implements Function {
   // than calling `Function.prototype.call()`. See sdk#31271.
   external call([arg1, arg2, arg3]);
 
-  external apply(thisArg, [List args]);
+  external apply(thisArg, [List<Object> args]);
 }

lib/src/node/render_options.dart

@@ -13,7 +13,7 @@ class RenderOptions {
   external String get data;
   external dynamic get importer;
   external dynamic get functions;
-  external List get includePaths; // contains Strings
+  external List<Object /* String */ > get includePaths;
   external bool get indentedSyntax;
   external bool get omitSourceMapUrl;
   external String get outFile;

lib/src/node/render_result.dart

@@ -24,7 +24,7 @@ class RenderResultStats {
   external int get start;
   external int get end;
   external int get duration;
-  external List get includedFiles; // contains Strings
+  external List<Object /* String */ > get includedFiles;
 
   external factory RenderResultStats(
       {String entry,

lib/src/parse/stylesheet.dart

@@ -1459,7 +1459,7 @@ relase. For details, see http://bit.ly/moz-document.
 
     resolveOperations() {
       if (operators == null) return;
-      while (!operators.isEmpty) {
+      while (operators.isNotEmpty) {
         resolveOneOperation();
       }
     }

lib/src/util/multi_dir_watcher.dart

@@ -37,7 +37,7 @@ class MultiDirWatcher {
   ///
   /// Returns a [Future] that completes when [events] is ready to emit events
   /// from [directory].
-  Future watch(String directory) {
+  Future<void> watch(String directory) {
     var isParentOfExistingDir = false;
     for (var existingDir in _watchers.keys.toList()) {
       if (!isParentOfExistingDir &&

lib/src/util/no_source_map_buffer.dart

@@ -19,7 +19,7 @@ class NoSourceMapBuffer implements SourceMapBuffer {
 
   T forSpan<T>(SourceSpan span, T callback()) => callback();
   void write(Object object) => _buffer.write(object);
-  void writeAll(Iterable objects, [String separator = ""]) =>
+  void writeAll(Iterable<Object> objects, [String separator = ""]) =>
       _buffer.writeAll(objects, separator);
   void writeCharCode(int charCode) => _buffer.writeCharCode(charCode);
   void writeln([Object object = ""]) => _buffer.writeln(object);

lib/src/util/source_map_buffer.dart

@@ -102,7 +102,7 @@ class SourceMapBuffer implements StringBuffer {
     }
   }
 
-  void writeAll(Iterable objects, [String separator = ""]) =>
+  void writeAll(Iterable<Object> objects, [String separator = ""]) =>
       write(objects.join(separator));
 
   void writeCharCode(int charCode) {

lib/src/utils.dart

@@ -18,7 +18,7 @@ import 'util/character.dart';
 final _noSourceUrl = Uri.parse("-");
 
 /// Converts [iter] into a sentence, separating each word with [conjunction].
-String toSentence(Iterable iter, [String conjunction]) {
+String toSentence(Iterable<Object> iter, [String conjunction]) {
   conjunction ??= "and";
   if (iter.length == 1) return iter.first.toString();
   return iter.take(iter.length - 1).join(", ") + " $conjunction ${iter.last}";
@@ -165,11 +165,19 @@ int codeUnitIndexToCodepointIndex(String string, int codeUnitIndex) {
 }
 
 /// Returns whether [list1] and [list2] have the same contents.
-bool listEquals<T>(List<T> list1, List<T> list2) =>
-    const ListEquality().equals(list1, list2);
+bool listEquals(List<Object> list1, List<Object> list2) =>
+    const ListEquality<Object>().equals(list1, list2);
 
 /// Returns a hash code for [list] that matches [listEquals].
-int listHash(List list) => const ListEquality().hash(list);
+int listHash(List<Object> list) => const ListEquality<Object>().hash(list);
+
+/// Returns whether [map1] and [map2] have the same contents.
+bool mapEquals(Map<Object, Object> map1, Map<Object, Object> map2) =>
+    const MapEquality<Object, Object>().equals(map1, map2);
+
+/// Returns a hash code for [map] that matches [mapEquals].
+int mapHash(Map<Object, Object> map) =>
+    const MapEquality<Object, Object>().hash(map);
 
 /// Returns a stack frame for the given [span] with the given [member] name.
 ///
@@ -395,7 +403,7 @@ void mapAddAll2<K1, K2, V>(
 
 /// Rotates the element in list from [start] (inclusive) to [end] (exclusive)
 /// one index higher, looping the final element back to [start].
-void rotateSlice(List list, int start, int end) {
+void rotateSlice(List<Object> list, int start, int end) {
   var element = list[end - 1];
   for (var i = start; i < end; i++) {
     var next = list[i];

lib/src/value/map.dart

@@ -2,10 +2,9 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
-import 'package:collection/collection.dart';
-
 import '../visitor/interface/value.dart';
 import '../value.dart';
+import '../utils.dart';
 import 'external/value.dart' as ext;
 
 class SassMap extends Value implements ext.SassMap {
@@ -33,11 +32,9 @@ class SassMap extends Value implements ext.SassMap {
   SassMap assertMap([String name]) => this;
 
   bool operator ==(other) =>
-      (other is SassMap &&
-          const MapEquality().equals(other.contents, contents)) ||
+      (other is SassMap && mapEquals(other.contents, contents)) ||
       (contents.isEmpty && other is SassList && other.asList.isEmpty);
 
-  int get hashCode => contents.isEmpty
-      ? const SassList.empty().hashCode
-      : const MapEquality().hash(contents);
+  int get hashCode =>
+      contents.isEmpty ? const SassList.empty().hashCode : mapHash(contents);
 }

lib/src/visitor/async_evaluate.dart

@@ -42,7 +42,8 @@ import 'interface/modifiable_css.dart';
 import 'interface/statement.dart';
 
 /// A function that takes a callback with no arguments.
-typedef _ScopeCallback = Future Function(Future Function() callback);
+typedef _ScopeCallback = Future<void> Function(
+    Future<void> Function() callback);
 
 /// Converts [stylesheet] to a plain CSS tree.
 ///
@@ -675,7 +676,7 @@ class _EvaluateVisitor
       ModifiableCssParentNode newParent,
       AtRootQuery query,
       List<ModifiableCssParentNode> included) {
-    var scope = (Future callback()) async {
+    var scope = (Future<void> callback()) async {
       // We can't use [_withParent] here because it'll add the node to the tree
       // in the wrong place.
       var oldParent = _parent;
@@ -985,7 +986,7 @@ class _EvaluateVisitor
   }
 
   /// Adds the stylesheet imported by [import] to the current document.
-  Future _visitDynamicImport(DynamicImport import) async {
+  Future<void> _visitDynamicImport(DynamicImport import) async {
     var result = await _loadStylesheet(import.url, import.span);
     var importer = result.item1;
     var stylesheet = result.item2;
@@ -1104,7 +1105,7 @@ class _EvaluateVisitor
   }
 
   /// Adds a CSS import for [import].
-  Future _visitStaticImport(StaticImport import) async {
+  Future<void> _visitStaticImport(StaticImport import) async {
     // NOTE: this logic is largely duplicated in [visitCssImport]. Most changes
     // here should be mirrored there.
 
@@ -1580,6 +1581,7 @@ class _EvaluateVisitor
 
     _verifyArguments(positional.length, named, IfExpression.declaration, node);
 
+    // ignore: prefer_is_empty
     var condition = positional.length > 0 ? positional[0] : named["condition"];
     var ifTrue = positional.length > 1 ? positional[1] : named["if-true"];
     var ifFalse = positional.length > 2 ? positional[2] : named["if-false"];

lib/src/visitor/evaluate.dart

@@ -5,7 +5,7 @@
 // DO NOT EDIT. This file was generated from async_evaluate.dart.
 // See tool/grind/synchronize.dart for details.
 //
-// Checksum: 71e3dfeef2683bd246e21ddfd25b21df408cf18e
+// Checksum: f316e802a42334d416c62f1d60d281a8262016f2
 //
 // ignore_for_file: unused_import
 
@@ -1574,6 +1574,7 @@ class _EvaluateVisitor
 
     _verifyArguments(positional.length, named, IfExpression.declaration, node);
 
+    // ignore: prefer_is_empty
     var condition = positional.length > 0 ? positional[0] : named["condition"];
     var ifTrue = positional.length > 1 ? positional[1] : named["if-true"];
     var ifFalse = positional.length > 2 ? positional[2] : named["if-false"];

lib/src/visitor/find_imports.dart

@@ -11,7 +11,7 @@ List<DynamicImport> findImports(Stylesheet stylesheet) =>
 
 /// A visitor that traverses a stylesheet and records all the [DynamicImport]s
 /// it contains.
-class _FindImportsVisitor extends RecursiveStatementVisitor {
+class _FindImportsVisitor extends RecursiveStatementVisitor<void> {
   final _imports = <DynamicImport>[];
 
   List<DynamicImport> run(Stylesheet stylesheet) {

lib/src/visitor/serialize.dart

@@ -106,7 +106,8 @@ String serializeSelector(Selector selector, {bool inspect = false}) {
 }
 
 /// A visitor that converts CSS syntax trees to plain strings.
-class _SerializeVisitor implements CssVisitor, ValueVisitor, SelectorVisitor {
+class _SerializeVisitor
+    implements CssVisitor<void>, ValueVisitor<void>, SelectorVisitor<void> {
   /// A buffer that contains the CSS produced so far.
   final SourceMapBuffer _buffer;
 

test/cli/shared.dart

@@ -17,7 +17,7 @@ void sharedTests(
         {Map<String, String> environment})) {
   /// Runs the executable on [arguments] plus an output file, then verifies that
   /// the contents of the output file match [expected].
-  Future expectCompiles(List<String> arguments, expected,
+  Future<void> expectCompiles(List<String> arguments, expected,
       {Map<String, String> environment}) async {
     var sass = await runSass([...arguments, "out.css", "--no-source-map"],
         environment: environment);

test/cli/shared/watch.dart

@@ -31,7 +31,7 @@ void sharedTests(Future<TestProcess> runSass(Iterable<String> arguments)) {
     /// Modifying a file very quickly after it was processed can go
     /// unrecognized, especially on Windows where filesystem operations can have
     /// very high delays.
-    Future tickIfPoll() => poll ? tick : Future.value();
+    Future<void> tickIfPoll() => poll ? tick : Future.value();
 
     group("${poll ? 'with' : 'without'} --poll", () {
       group("when started", () {

test/ensure_npm_package.dart

@@ -11,7 +11,7 @@ import 'package:sass/src/io.dart';
 
 import 'io.dart';
 
-hybridMain(StreamChannel channel) async {
+void hybridMain(StreamChannel<Object> channel) async {
   ensureUpToDate("build/npm/sass.dart.js", "pub run grinder npm-package");
   channel.sink.close();
 }
@@ -19,7 +19,7 @@ hybridMain(StreamChannel channel) async {
 /// Ensures that the NPM package is compiled and up-to-date.
 ///
 /// This is safe to call even outside the Dart VM.
-Future ensureNpmPackage() async {
+Future<void> ensureNpmPackage() async {
   // spawnHybridUri() doesn't currently work on Windows and Node due to busted
   // path handling in the SDK.
   if (isNode && isWindows) return;

test/hybrid.dart

@@ -12,21 +12,21 @@ Future<String> createTempDir() async => (await runHybridExpression(
     '(await Directory.systemTemp.createTemp("dart_sass_")).path')) as String;
 
 /// Writes [text] to [path].
-Future writeTextFile(String path, String text) => runHybridExpression(
+Future<void> writeTextFile(String path, String text) => runHybridExpression(
     'new File(message[0]).writeAsString(message[1])', [path, text]);
 
 /// Creates a directoy at [path].
-Future createDirectory(String path) =>
+Future<void> createDirectory(String path) =>
     runHybridExpression('new Directory(message).create()', path);
 
 /// Recursively deletes the directoy at [path].
-Future deleteDirectory(String path) =>
+Future<void> deleteDirectory(String path) =>
     runHybridExpression('new Directory(message).delete(recursive: true)', path);
 
 /// Runs [expression], which may be asynchronous, in a hybrid isolate.
 ///
 /// Returns the result of [expression] if it's JSON-serializable.
-Future runHybridExpression(String expression, [message]) async {
+Future<Object> runHybridExpression(String expression, [message]) async {
   var channel = spawnHybridCode('''
     import 'dart:async';
     import 'dart:convert';

test/node_api/function_test.dart

@@ -180,7 +180,7 @@ void main() {
               data: "a {b: foo()}",
               functions: jsify({
                 "foo": allowInterop((done) {
-                  Future.delayed(Duration.zero).then((_) {
+                  Timer(Duration.zero, () {
                     done(callConstructor(sass.types.Number, [1]));
                   });
                 })
@@ -210,7 +210,7 @@ void main() {
           data: "a {b: foo()}",
           functions: jsify({
             "foo": allowInterop((done) {
-              Future.delayed(Duration.zero).then((_) {
+              Timer(Duration.zero, () {
                 done(JSError("aw beans"));
               });
             })
@@ -223,7 +223,7 @@ void main() {
           data: "a {b: foo()}",
           functions: jsify({
             "foo": allowInterop((done) {
-              Future.delayed(Duration.zero).then((_) {
+              Timer(Duration.zero, () {
                 done(callConstructor(sass.types.Error, ["aw beans"]));
               });
             })
@@ -236,7 +236,7 @@ void main() {
           data: "a {b: foo()}",
           functions: jsify({
             "foo": allowInterop((done) {
-              Future.delayed(Duration.zero).then((_) {
+              Timer(Duration.zero, () {
                 done(null);
               });
             })
@@ -249,7 +249,7 @@ void main() {
           data: "a {b: foo()}",
           functions: jsify({
             "foo": allowInterop((done) {
-              Future.delayed(Duration.zero).then((_) {
+              Timer(Duration.zero, () {
                 done();
               });
             })
@@ -291,7 +291,7 @@ void main() {
                 data: "a {b: foo()}",
                 functions: jsify({
                   "foo": allowInterop((done) {
-                    Future.delayed(Duration.zero).then((_) {
+                    Timer(Duration.zero, () {
                       done(callConstructor(sass.types.Number, [1]));
                     });
                   })
@@ -313,7 +313,7 @@ void main() {
             data: "a {b: foo()}",
             functions: jsify({
               "foo": allowInterop((done) {
-                Future.delayed(Duration.zero).then((_) {
+                Timer(Duration.zero, () {
                   done(JSError("aw beans"));
                 });
               })
@@ -327,7 +327,7 @@ void main() {
             data: "a {b: foo()}",
             functions: jsify({
               "foo": allowInterop((done) {
-                Future.delayed(Duration.zero).then((_) {
+                Timer(Duration.zero, () {
                   done(null);
                 });
               })
@@ -341,7 +341,7 @@ void main() {
             data: "a {b: foo()}",
             functions: jsify({
               "foo": allowInterop((done) {
-                Future.delayed(Duration.zero).then((_) {
+                Timer(Duration.zero, () {
                   done();
                 });
               })

test/node_api/importer_test.dart

@@ -589,7 +589,7 @@ void main() {
           render(RenderOptions(
               data: "@import 'foo'",
               importer: allowInterop((_, __, done) {
-                Future.delayed(Duration.zero).then((_) {
+                Timer(Duration.zero, () {
                   done(NodeImporterResult(contents: 'a {b: c}'));
                 });
               }))),
@@ -601,7 +601,7 @@ void main() {
           renderError(RenderOptions(
               data: "@import 'foo'",
               importer: allowInterop((_, __, done) {
-                Future.delayed(Duration.zero).then((_) {
+                Timer(Duration.zero, () {
                   done(JSError('oh no'));
                 });
               }))),
@@ -651,7 +651,7 @@ void main() {
             render(RenderOptions(
                 data: "@import 'foo'",
                 importer: allowInterop((_, __, done) {
-                  Future.delayed(Duration.zero).then((_) {
+                  Timer(Duration.zero, () {
                     done(NodeImporterResult(contents: 'a {b: c}'));
                   });
                 }),
@@ -686,7 +686,7 @@ void main() {
             renderError(RenderOptions(
                 data: "@import 'foo'",
                 importer: allowInterop((_, __, done) {
-                  Future.delayed(Duration.zero).then((_) {
+                  Timer(Duration.zero, () {
                     done(JSError('oh no'));
                   });
                 }),

test/node_api/source_map_test.dart

@@ -12,7 +12,7 @@ import 'package:path/path.dart' as p;
 import 'package:source_maps/source_maps.dart';
 import 'package:test/test.dart';
 
-import 'package:sass/sass.dart' as dartSass;
+import 'package:sass/sass.dart' as dart_sass;
 
 import '../ensure_npm_package.dart';
 import '../hybrid.dart';
@@ -39,7 +39,8 @@ void main() {
 
     test("includes correct mappings", () {
       SingleMapping expectedMap;
-      dartSass.compileString("a {b: c}", sourceMap: (map) => expectedMap = map);
+      dart_sass.compileString("a {b: c}",
+          sourceMap: (map) => expectedMap = map);
       expectedMap.targetUrl = "out.css";
 
       expect(map, containsPair("mappings", expectedMap.toJson()["mappings"]));

test/node_api/utils.dart

@@ -108,8 +108,7 @@ void setEnvironmentVariable(String name, String value) {
 
 // Runs [callback] with the `SASS_PATH` environment variable set to [paths].
 T withSassPath<T>(List<String> paths, T callback()) {
-  var oldSassPath =
-      setEnvironmentVariable("SASS_PATH", paths.join(isWindows ? ';' : ':'));
+  setEnvironmentVariable("SASS_PATH", paths.join(isWindows ? ';' : ':'));
 
   try {
     return callback();

test/node_api/value/null_test.dart

@@ -14,7 +14,7 @@ import 'utils.dart';
 
 void main() {
   group("from a parameter", () {
-    var value;
+    Object value;
     setUp(() {
       value = parseValue("null");
     });

test/utils.dart

@@ -17,7 +17,7 @@ final _sourceMapCommentRegExp = RegExp(r"/\*# sourceMappingURL=(.*) \*/\s*$");
 ///
 /// Windows (or at least Appveyor) seems to require a more coarse-grained time
 /// than Unixes.
-Future get tick =>
+Future<void> get tick =>
     Future.delayed(Duration(milliseconds: isWindows ? 1000 : 50));
 
 /// Loads and decodes the source map embedded as a `data:` URI in [css].

tool/grind/benchmark.dart

@@ -68,7 +68,7 @@ benchmarkGenerate() async {
 /// If [header] is passed, it's written before [text]. If [footer] is passed,
 /// it's written after [text]. If the file already exists and is the expected
 /// length, it's not written.
-Future _writeNTimes(String path, String text, num times,
+Future<void> _writeNTimes(String path, String text, num times,
     {String header, String footer}) async {
   var file = File(path);
   var expectedLength = (header == null ? 0 : header.length + 1) +

tool/grind/npm.dart

@@ -69,7 +69,7 @@ npmReleasePackage() => _npm(release: true);
 void _npm({@required bool release}) {
   var json = {
     ...(jsonDecode(File('package/package.json').readAsStringSync())
-        as Map<String, dynamic>),
+        as Map<String, Object>),
     "version": version
   };
 

tool/grind/sanity_check.dart

@@ -4,10 +4,11 @@
 
 import 'dart:io';
 
-import 'package:collection/collection.dart';
 import 'package:grinder/grinder.dart';
 import 'package:pub_semver/pub_semver.dart';
 
+import 'package:sass/src/utils.dart';
+
 import 'utils.dart';
 
 @Task('Verify that the package is in a good state to release.')
@@ -17,7 +18,7 @@ sanityCheckBeforeRelease() {
     fail("TRAVIS_TAG $travisTag is different than pubspec version $version.");
   }
 
-  if (const ListEquality().equals(Version.parse(version).preRelease, ["dev"])) {
+  if (listEquals(Version.parse(version).preRelease, ["dev"])) {
     fail("$version is a dev release.");
   }
 

tool/grind/standalone.dart

@@ -7,7 +7,6 @@ import 'dart:io';
 
 import 'package:archive/archive.dart';
 import 'package:grinder/grinder.dart';
-import 'package:meta/meta.dart';
 import 'package:path/path.dart' as p;
 import 'package:http/http.dart' as http;
 
@@ -61,7 +60,7 @@ packageMacOs() => _buildPackage("macos");
 packageWindows() => _buildPackage("windows");
 
 /// Builds standalone 32- and 64-bit Sass packages for the given [os].
-Future _buildPackage(String os) async {
+Future<void> _buildPackage(String os) async {
   var client = http.Client();
   await Future.wait(["ia32", "x64"].map((architecture) async {
     // TODO: Compile a single executable that embeds the Dart VM and the

tool/grind/synchronize.dart

@@ -5,6 +5,9 @@
 import 'dart:convert';
 import 'dart:io';
 
+// See https://groups.google.com/a/dartlang.org/d/msg/misc/bZ0AGuEo41c/u05-1M7yAgAJ.
+//
+// ignore: deprecated_member_use
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ -56,7 +59,7 @@ synchronize() {
 /// original source where possible. It tracks the [_position] at the end of the
 /// text that's been written, and writes from that position to the new position
 /// whenever text needs to be emitted.
-class _Visitor extends RecursiveAstVisitor {
+class _Visitor extends RecursiveAstVisitor<void> {
   /// The source of the original asynchronous file.
   final String _source;