Typescript giving "Output Generation Failed" in Visual Studio 2012 with 0.9.5 - visual-studio-2012

Question

I've been using Typescript 0.9.5 for the last few days, and then suddenly today the JavaScript files just stopped being generated. I see an error "Output generation failed" in the Visual Studio status bar, but nothing in any of the output windows.
I've rebooted, and restarted Visual Studio, disabled Web Essentials, tried all the usual things.
The files are set as TypescriptCompile in the properties. I've tried adding new files, or editing old ones with no effect. The Project file hasn't been changed as far as I can tell (its in TFS and none of the TypeScript sections have been altered).
I've made sure both files are checked out, still nothing.
Update: I've managed to compile manually using tsc.exe from the command line, so it must be something in Visual Studio.

Answer 1

OK, so I solved the problem.
One of my files contained invalid typescript, specifically trying to export a class when not inside a module. This caused all typescript files to fail to generate, but with no useful error message.
The following file would cause the problem:
export class Test {
public DoSomething() {
}
}
Either removing the export keyword, or adding a wrapping module solved the problem.
I've raised it as an issue here: https://typescript.codeplex.com/workitem/2109
Update: More details.
The above syntax is valid if you are using the CommonJS or AMD module patterns.
To enable this in visual studio you need to edit the .csproj file and insert a new PropertyGroup:
<TypeScriptModuleKind>AMD</TypeScriptModuleKind>

Answer 2

If you have an export outside of an internal module Typescript tries to compile it as either commonjs or amd module format. The compilation will fail if the a --module flag is not present on the command line. Use your project properties to set it to the desired value (probably amd in your case).
More info on TypeScript modules : http://www.youtube.com/watch?v=KDrWLMUY0R0&hd=1