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

[sethladd]

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.

[nex3]

Added Duplicate label.
Marked as being merged into #14593.

[DartBot]

This issue has been moved to dart-lang/pub#783.