Please help make it more obvious when pub detects a file collision

[DartBot]

<img src="https://avatars.githubusercontent.com/u/5479?v=3" align="left" width="96" height="96"hspace="10"> Issue by sethladd
Originally opened as dart-lang/sdk#15668

---

I'm trying to help the new vanilla Dart of TodoMVC, but when I run pub build, I get this error:

--- Dec 12, 2013 3:57:28 PM Running pub build ... ---
Pub build failed, [65] Building todomvc_dart.....
[Info in Dart2JS]:
Generated todomvc_dart|web/dart/app.dart.js (127618 characters) in 0:00:07.610880
Build error:
Transforms {Dart2JS on todomvc_dart|web/dart/app.dart} all emitted asset todomvc_dart|web/dart/app.dart.js.
Build failed.

A couple of questions:

* Not sure what "all emitted asset" means. Was that an error? That is, is that good or bad? :)

* I think I see one transform in there (Dart2JS) but I also see the word "all".

* I'm not clear what the | means here. Why do we include the name of the project, and not just the path to the file/asset in question?

* No exception is emitted, so not sure how to give you more info. I ran this by right-clicking on pubspec.yaml and selected "pub build"

For the record, no build directory was created.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/188?v=3" align="left" width="48" height="48"hspace="10"> Comment by nex3

---

Added Duplicate label.
Marked as being merged into dart-archive/barback#18.