Type casts no longer work after ILRepack

Question

I am trying to create a single executable from the binaries of a project. This is what I have:

• A shared library dll, written in F#, I will refer to it by A
• A library dll, written in C# that implements a module interface (IModule) from A. I will refer to this library as B
• An executable, written in F#, that at bootstrap time detects all available implementations of the IModule interface from A and instantiates the respective types - there is such implementation in B. I will refer to the executable as C

All projects target .NET 4.0; the F# projects use F# 3.0 (FSharp.Core 4.3.0.0), I am using Visual Studio 2017 Community.

All the logic is working fine when the files are not packed together (as if ran from the exe project's bin/Debug directory). When I produce the merged executable (using ILRepack ), then the logic in the executable no longer detects which classes from B implement interfaces from A. In particular, I have the following check:

if (typedefof<IModule>.IsAssignableFrom(someType)) then ...

which is a code fragment from A that I use to detect IModule implemenations. I suppose the ILRepack merging causes some type information to be lost in the process, preventing the above line from working.

A solution I used to get this work was to exclude the library A from the merged exe and just bring it along.

Is there a way to still have a single executable and get the type detection working? I'd prefer using a similar approach as the above interface detection, because once I find the desired types, I need them to be cast to IModule in order to further use them in my code.

My goal is to have the above 3 libraries bundled together in a single executable. However I'd also want to have other dll files, which implement IModule from A and be placed besides the executable. These dlls will be developed independently from A, B and C and their presence around the merged executable will vary depending on my use cases. I cant get them to work for the same reason.

Note, I also include the FSharp.Core dll in the packed executable for obvious reasons.