anchor.diff:          il.Emit(OpCodes.Ldarg_0)
           il.Emit(OpCodes.Ldarg_2)
           il.Emit(OpCodes.Ldarg_3)
  -        il.EmitCall(OpCodes.Call, rebuildMeth, null)
  +        il.Call(rebuildMeth, false)
           il.Emit(OpCodes.Ret)
   
           let newSelf = meth.CreateDelegate<FuncRef1<Dispatcher<'r>, obj[], obj, 'r, bool>>()
  
positive.code:         il.Emit(OpCodes.Ldarg_2)
          il.Emit(OpCodes.Ldarg_3)
          il.Emit(OpCodes.Ldarg_S, 4uy)
          il.EmitCall(OpCodes.Call, rebuildMeth, null)
          il.Emit(OpCodes.Ret)
  
          let newSelf = meth.CreateDelegate<FuncRef1<Dispatcher<'b, 'r>, obj[], obj, 'b, 'r, bool>>()
  
negative.code:                 il.Emit(OpCodes.Ldloc, dyn)  
                  il.OfObj(parameters.[0].ParameterType)
                  il.Emit(OpCodes.Ldarg_3)
  
                  il.Call(meth, true)
  
                  il.Convert(meth.ReturnType, typeof<'r>)
                  let l = il.DeclareLocal(typeof<'r>)
  