Unity internal compiler error with custom dll

问题

I spent some hours trying solutions I found online but nothing worked so here's my question for Stackoverflowers.

I made a small plugin for Unity and imported the dll into my project folder. It works fine when I launch the game within the editor but if I try to compile I get the following:

Internal compiler error. See the console log for more information. output was:
Unhandled Exception: System.Reflection.ReflectionTypeLoadException: The classes in the module cannot be loaded.

  at (wrapper managed-to-native) System.Reflection.Assembly:GetTypes (bool)

  at System.Reflection.Assembly.GetTypes () [0x00000] in <filename unknown>:0 

  at Mono.CSharp.RootNamespace.ComputeNamespaces (System.Reflection.Assembly assembly, System.Type extensionType) [0x00000] in <filename unknown>:0 

  at Mono.CSharp.RootNamespace.ComputeNamespace (Mono.CSharp.CompilerContext ctx, System.Type extensionType) [0x00000] in <filename unknown>:0 

  at Mono.CSharp.GlobalRootNamespace.ComputeNamespaces (Mono.CSharp.CompilerContext ctx) [0x00000] in <filename unknown>:0 

  at Mono.CSharp.Driver.LoadReferences () [0x00000] in <filename unknown>:0 

  at Mono.CSharp.Driver.Compile () [0x00000] in <filename unknown>:0 

  at Mono.CSharp.Driver.Main (System.String[] args) [0x00000] in <filename unknown>:0

What I did so far:

my dll is in the Plugins folder in Assets
tried to place the dll (also) in the project root
tried with and without namespaces
set .NET 2.0 in Unity

And by the way, it works fine in Unity Editor so it should be pretty clear that I made it right as I followed the instructions in the official Plugins making guide.

Thanks for any help

回答1:

When I deleted the dll from the Plugins folder while leaving just a copy of it in the project's root folder, it worked.

So in this case the solution is to leave the dll just in the project's root folder and nowhere else.

I'm not sure why though, so part of the question is still open.

回答2:

What worked for me was setting the target platform lower(from 4.5 to 3.5). As suggested here: http://forum.unity3d.com/threads/ideas-reflectiontypeloadexception-the-classes-in-the-module-cannot-be-loaded.230389/

回答3:

The thing I needed to do was change the API compatibility level from .NET Subset 2.0 to .NET 2.0. Suddenly all was fine. Probably the threading task was doing some problems.

Please see reference