diff --git a/.gitignore b/.gitignore
index 25a1df3..49ce72d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,9 +1,3 @@
-.buildlog
-.DS_Store
-.idea
-.pub/
-.settings/
-build/
-packages
+.dart_tool/
 .packages
 pubspec.lock
diff --git a/.travis.yml b/.travis.yml
index 610bd03..d402e3f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,17 +1,18 @@
 language: dart
 sudo: false
 dart:
-  - stable
+  #- stable
   - dev
 dart_task:
   - test: -p vm
     xvfb: false
-  - test: -p firefox
+  # Set concurrency to 1 to avoid flakes on Travis
+  - test: -p firefox -j 1
   - dartanalyzer
 
 matrix:
   include:
-  - dart: stable
+  - dart: dev
     dart_task: dartfmt
 
 # Only building master means that we don't run two builds for each pull request.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 367abee..302c8d3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.0.4
+
+* Now requires Dart 2.
+
 ## 1.0.3
 
 * Work around an inference bug in the new common front-end.
diff --git a/analysis_options.yaml b/analysis_options.yaml
deleted file mode 100644
index a10d4c5..0000000
--- a/analysis_options.yaml
+++ /dev/null
@@ -1,2 +0,0 @@
-analyzer:
-  strong-mode: true
diff --git a/codereview.settings b/codereview.settings
deleted file mode 100644
index 3de3f59..0000000
--- a/codereview.settings
+++ /dev/null
@@ -1,3 +0,0 @@
-CODE_REVIEW_SERVER: https://codereview.chromium.org/
-VIEW_VC: https://github.com/dart-lang/boolean_selector/commit/
-CC_LIST: reviews@dartlang.org
\ No newline at end of file
diff --git a/lib/src/evaluator.dart b/lib/src/evaluator.dart
index 6401a37..f2ed7d6 100644
--- a/lib/src/evaluator.dart
+++ b/lib/src/evaluator.dart
@@ -2,8 +2,6 @@
 // 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 'package:collection/collection.dart';
-
 import 'ast.dart';
 import 'visitor.dart';
 
@@ -17,7 +15,7 @@ class Evaluator implements Visitor<bool> {
 
   Evaluator(semantics)
       : _semantics = semantics is Iterable
-            ? DelegatingIterable.typed(semantics.toSet()).contains
+            ? semantics.toSet().contains
             : semantics as _Semantics;
 
   bool visitVariable(VariableNode node) => _semantics(node.name);
diff --git a/pubspec.yaml b/pubspec.yaml
index 27961af..580b404 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,16 +1,15 @@
 name: boolean_selector
-version: 1.0.3
+version: 1.0.4
 description: A flexible syntax for boolean expressions.
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/dart-lang/boolean_selector
 
 environment:
-  sdk: '>=1.8.0 <2.0.0'
+  sdk: '>=2.0.0-dev.58 <3.0.0'
 
 dependencies:
-  collection: '^1.5.0'
   source_span: '^1.0.0'
   string_scanner: '>=0.1.1 <2.0.0'
 
 dev_dependencies:
-  test: '^0.12.0'
+  test: ^1.2.0
diff --git a/test/parser_test.dart b/test/parser_test.dart
index 9e801f2..1b7128f 100644
--- a/test/parser_test.dart
+++ b/test/parser_test.dart
@@ -8,16 +8,16 @@ import 'package:boolean_selector/src/ast.dart';
 import 'package:boolean_selector/src/parser.dart';
 
 /// A matcher that asserts that a value is a [ConditionalNode].
-Matcher _isConditionalNode = new isInstanceOf<ConditionalNode>();
+final _isConditionalNode = new TypeMatcher<ConditionalNode>();
 
 /// A matcher that asserts that a value is an [OrNode].
-Matcher _isOrNode = new isInstanceOf<OrNode>();
+final _isOrNode = new TypeMatcher<OrNode>();
 
 /// A matcher that asserts that a value is an [AndNode].
-Matcher _isAndNode = new isInstanceOf<AndNode>();
+final _isAndNode = new TypeMatcher<AndNode>();
 
 /// A matcher that asserts that a value is a [NotNode].
-Matcher _isNotNode = new isInstanceOf<NotNode>();
+final _isNotNode = new TypeMatcher<NotNode>();
 
 void main() {
   group("parses a conditional expression", () {