diff --git a/CHANGELOG.md b/CHANGELOG.md
index 771bcd0..319e000 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 0.12.2+3
+
+* Fixed implementation of ArgResults.options to really use Iterable<String>
+  instead of Iterable<dynamic> cast to Iterable<String>.
+
 ## 0.12.2+2
 
 * Updated dependency constraint on `unittest`.
diff --git a/lib/src/arg_results.dart b/lib/src/arg_results.dart
index de9cca7..15fb5bb 100644
--- a/lib/src/arg_results.dart
+++ b/lib/src/arg_results.dart
@@ -70,7 +70,7 @@
   /// This includes the options whose values were parsed or that have defaults.
   /// Options that weren't present and have no default will be omitted.
   Iterable<String> get options {
-    var result = new Set.from(_parsed.keys);
+    var result = new Set<String>.from(_parsed.keys);
 
     // Include the options that have defaults.
     _parser.options.forEach((name, option) {
diff --git a/pubspec.yaml b/pubspec.yaml
index c625ad0..07af8ec 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: args
-version: 0.12.2+2
+version: 0.12.2+3
 author: "Dart Team <misc@dartlang.org>"
 homepage: https://github.com/dart-lang/args
 description: >