Dart 0.8.10_r30104 (DEV) を使用していますが、Javascript を生成できません (ただし、アプリ自体は Dartrium で実行できます)。
builder.dart で「Javascript の生成」を選択すると、エラーが表示されます。
--- Nov 12, 2013 7:35:43 AM Running dart2js... ---
F:\dart\dart-sdk\bin\dart2js.bat --out=E:\My Books\Sitepoint\Sample\build.dart.js E:\My Books\Sitepoint\Sample\build.dart
/E:/My Books/Sitepoint/Sample/packages/polymer/builder.dart:83:8: Error: Library not found 'dart:io'.
import 'dart:io';
^^^^^^^^^
/E:/My Books/Sitepoint/Sample/packages/polymer/src/build/linter.dart:11:8: Error: Library not found 'dart:io'.
import 'dart:io';
^^^^^^^^^
/E:/My Books/Sitepoint/Sample/packages/barback/src/asset.dart:9:8: Error: Library not found 'dart:io'.
import 'dart:io';
^^^^^^^^^
...
/E:/My Books/Sitepoint/Sample/packages/analyzer/src/generated/element.dart:7220:17: Hint: The class 'VoidTypeImpl' overrides 'operator==', but not 'get hashCode'.
bool operator ==(Object object) => identical(object, this);
^^
/E:/My Books/Sitepoint/Sample/packages/analyzer/src/generated/element.dart:4874:17: Hint: The class 'PropertyAccessorElementImpl' overrides 'operator==', but not 'get hashCode'.
bool operator ==(Object object) => super == object && identical(isGetter, ((object as PropertyAccessorElement)).isGetter);
^^
Error: Compilation failed.
===
何が悪かったのか？