Extracted from a comment posted by @onovotny in issue #594.

One update here. You can read more on my blog, but the target here shouldn't be dnx451 or dnxcore*

Instead for Autofac, it should use dotnet. That is what CoreCLR things should target and will then support anything its contracts do. DNX isn't the only thing that can use it in other words.

I suspect that the Autofac main core package does not actually need any DNX-specific types/libraries, it needs CoreCLR. Then the other package (the former autofac.dnx one) does reference dnx-specifics and should target dnx*. Point being that the main autofac shouldn't as it'd work on more platforms than that.

The blog post in the quote above has some good information.