Marshallers Required Implicitly

[juanpedromoreno]

The current @service macro is requiring the Marshallers with the implicitly identifier, this is preventing to provide other marshallers externally of the macro, since the generated companion object is not able to find them.

https://github.com/frees-io/freestyle-rpc/blob/9f898c9/modules/internal/src/main/scala/service.scala#L205-L206

A potential solution would be changing the current macro, where instead of a val, we implement them as a def, requiring them as part of the method definition. Example:

q"""
       $wartSuppress
       def ${Pat.Var.Term(descriptorName)}(implicit RQM: _root_.io.grpc.MethodDescriptor.Marshaller[$requestType], RSM: _root_.io.grpc.MethodDescriptor.Marshaller[$responseType]): _root_.io.grpc.MethodDescriptor[$requestType, $responseType] = {
         $encodersImport
         _root_.io.grpc.MethodDescriptor
           .newBuilder(RQM, RSM)
           .setType(${utils.methodType(streamingType)})
           .setFullMethodName(
             _root_.io.grpc.MethodDescriptor.generateFullMethodName(${Lit.String(algName.value)}, ${Lit
      .String(name.value)}))
           .build()
       }
      """

[fedefernandez]

I've this WIP #279 with all the macros and server module migrated (including tests). The problem is I'm getting this weird error:

[error] Caused by: sbt.ForkMain$ForkError: java.lang.NullPointerException: requestMarshaller
[error] 	at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:787)
[error] 	at io.grpc.MethodDescriptor.<init>(MethodDescriptor.java:230)
[error] 	at io.grpc.MethodDescriptor.<init>(MethodDescriptor.java:40)
[error] 	at io.grpc.MethodDescriptor$Builder.build(MethodDescriptor.java:567)
[error] 	at freestyle.rpc.protocol.Utils$service$RPCAvroService$.unaryMethodDescriptor(Utils.scala:19)
[error] 	at freestyle.rpc.protocol.Utils$service$RPCAvroService$.bindService(Utils.scala:54)
[error] 	at freestyle.rpc.protocol.Utils$FreesRuntime.$init$(Utils.scala:550)
[error] 	at freestyle.rpc.protocol.Utils$implicits$.<init>(Utils.scala:572)
[error] 	at freestyle.rpc.protocol.Utils$implicits$.<clinit>(Utils.scala)
[error] 	at freestyle.rpc.protocol.RPCTests.$anonfun$new$4(RPCTests.scala:73)

[pepegar]

fixed in #330