This looks perfect!
Gonna wait for a bit with merging, trying to close some bug issues first.

@JohanLarsson We need to test this in a WPF project because I think it will suffer from the same issue as tunnelvisionlabs/ReferenceAssemblyAnnotator#81.

For your remark about WPF, I don't know if that can be an issue. I'd think that the way both package work are quite different.
In our case we add a source file into the project directly, we're not adding things to the build pipeline dynamically (I don't know what ReferenceAssemblyAnnotator does, but from the name, it seems that it does specific things, right?)

For your remark about WPF, I don't know if that can be an issue. I'd think that the way both package work are quite different.
In our case we add a source file into the project directly, we're not adding things to the build pipeline dynamically (I don't know what ReferenceAssemblyAnnotator does, but from the name, it seems that it does specific things, right?)

The problem with WPF is only related to including a source file into the project. I.e. it's related to added <Compile> items, not to <Reference> items. WPF creates a temp copy of the csproj using the file system and only carries certain things over into it. In the mix, our added <Compile> item is never provided a way to show up in this temp project.

Specifically, the problem is that the .targets file is not included in the WPF temp project and so <Compile Include="$(OwnershipAttributesPath)" Visible="false" /> never happens for the temp project.

Good news, I found an easy fix to work around the WPF problem. https://github.com/tunnelvisionlabs/ReferenceAssemblyAnnotator/pull/82/files#diff-e981fad1d30fcb8e912da7c14997e6caR20

Closing since this PR was mainly a demonstration. If you'd like to take this approach in the future, this can serve as a reference.