Sending NetworkPlayer object with ClientRpc

I'm trying to keep an updated list of connected players in every client instance, but I always get a compile error when I try to use a NetworkPlayer as a parameter for a ClientRpc method. Here's an example of a problematic code snippet.

 public class NetTest : NetworkBehaviour {
 
     [ClientRpc]
     public void RpcTest(NetworkPlayer netPlayer){        
     }
 }

and the errors that I get are

 UNetWeaver error: Exception :System.ArgumentException: Member 'System.Int32 UnityEngine.NetworkPlayer::index' is declared in another module and needs to be imported
   at Mono.Cecil.MetadataBuilder.LookupToken (IMetadataTokenProvider provider) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.Cil.CodeWriter.WriteOperand (Mono.Cecil.Cil.Instruction instruction) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.Cil.CodeWriter.WriteInstructions () [0x00000] in <filename unknown>:0 
   at Mono.Cecil.Cil.CodeWriter.WriteResolvedMethodBody (Mono.Cecil.MethodDefinition method) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.Cil.CodeWriter.WriteMethodBody (Mono.Cecil.MethodDefinition method) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.MetadataBuilder.AddMethod (Mono.Cecil.MethodDefinition method) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.MetadataBuilder.AddMethods (Mono.Cecil.TypeDefinition type) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.MetadataBuilder.AddType (Mono.Cecil.TypeDefinition type) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.MetadataBuilder.AddTypeDefs () [0x00000] in <filename unknown>:0 
   at Mono.Cecil.MetadataBuilder.BuildTypes () [0x00000] in <filename unknown>:0 
   at Mono.Cecil.MetadataBuilder.BuildModule () [0x00000] in <filename unknown>:0 
   at Mono.Cecil.MetadataBuilder.BuildMetadata () [0x00000] in <filename unknown>:0 
   at Mono.Cecil.ModuleWriter.<BuildMetadata>b__0 (Mono.Cecil.MetadataBuilder builder, Mono.Cecil.MetadataReader _) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.ModuleDefinition.Read[MetadataBuilder,MetadataBuilder] (Mono.Cecil.MetadataBuilder item, System.Func`3 read) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.ModuleWriter.BuildMetadata (Mono.Cecil.ModuleDefinition module, Mono.Cecil.MetadataBuilder metadata) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.ModuleWriter.WriteModuleTo (Mono.Cecil.ModuleDefinition module, System.IO.Stream stream, Mono.Cecil.WriterParameters parameters) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.ModuleDefinition.Write (System.IO.Stream stream, Mono.Cecil.WriterParameters parameters) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.ModuleDefinition.Write (System.String fileName, Mono.Cecil.WriterParameters parameters) [0x00000] in <filename unknown>:0 
   at Mono.Cecil.AssemblyDefinition.Write (System.String fileName, Mono.Cecil.WriterParameters parameters) [0x00000] in <filename unknown>:0 
   at Unity.UNetWeaver.Weaver.Weave (System.String assName, IEnumerable`1 dependencies, IAssemblyResolver assemblyResolver, System.String unityEngineDLLPath, System.String unityUNetDLLPath, System.String outputDir) [0x001d1] in C:\buildslave\unity\build\Extensions\Networking\Weaver\UNetWeaver.cs:1616 
   at Unity.UNetWeaver.Weaver.WeaveAssemblies (IEnumerable`1 assemblies, IEnumerable`1 dependencies, IAssemblyResolver assemblyResolver, System.String outputDir, System.String unityEngineDLLPath, System.String unityUNetDLLPath) [0x00062] in C:\buildslave\unity\build\Extensions\Networking\Weaver\UNetWeaver.cs:1640 
 UnityEngine.Debug:LogError(Object)
 Unity.UNetWeaver.Log:Error(String) (at C:/buildslave/unity/build/Extensions/Networking/Weaver/Program.cs:20)
 Unity.UNetWeaver.Weaver:WeaveAssemblies(IEnumerable`1, IEnumerable`1, IAssemblyResolver, String, String, String) (at C:/buildslave/unity/build/Extensions/Networking/Weaver/UNetWeaver.cs:1647)
 Unity.UNetWeaver.Program:Process(String, String, String, String[], String[], IAssemblyResolver, Action`1, Action`1) (at C:/buildslave/unity/build/Extensions/Networking/Weaver/Program.cs:34)
 UnityEditor.Scripting.Serialization.Weaver:WeaveUnetFromEditor(String, String, String, String, Boolean)
 

and

 Failure generating network code.
 UnityEditor.Scripting.Serialization.Weaver:WeaveUnetFromEditor(String, String, String, String, Boolean)

It seems to work fine whenever I change the parameter to an int or string. Are NetworkPlayers impossible to send over Rpc? I'm using Unity 5.2.0f3