diff --git a/lib/src/property.dart b/lib/src/property.dart
index a2cf97c..69f5c54 100644
--- a/lib/src/property.dart
+++ b/lib/src/property.dart
@@ -1245,4 +1245,4 @@
   num get height => (top != null ? top : 0) + (bottom != null ? bottom : 0);
 }
 
-/*=T*/ _mergeVal/*<T>*/(/*=T*/ x, /*=T*/ y) => y != null ? y : x;
+T _mergeVal<T>(T x, T y) => y != null ? y : x;
diff --git a/pubspec.yaml b/pubspec.yaml
index 2111ec9..225b601 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,10 +1,10 @@
 name: csslib
-version: 0.14.0
+version: 0.14.1-dev
 author: Dart Team <misc@dartlang.org>
 description: A library for parsing CSS.
 homepage: https://github.com/dart-lang/csslib
 environment:
-  sdk: '>=1.1.0 <2.0.0'
+  sdk: '>=1.21.0 <2.0.0-dev.infinity'
 dependencies:
   args: '>=0.9.0 <0.14.0'
   logging: '>=0.9.0 <0.12.0'