Error while compiling Guardian: 'BasePlayer' does not contain a definition for 'ClientRPCPlayer' and no accessible extension method 'ClientRPCPlayer' accepting a first argument of type 'BasePlayer' could be found (are you missing a using directive or an assembly reference?) | Line: 9698, Pos: 26

changes needed:  around line 390

                               if(!deflection)
                                {
                                    // Facepunch removed Pool.GetList<T>() / Pool.FreeList (CS0117).
                                    // Current Facepunch.Pool API: Get<List<T>>() rents a pooled list,
                                    // FreeUnmanaged<T>(ref list) returns it. Same Vis.Entities usage.
                                    var deflectors = Pool.Get<List<BaseEntity>>();

                                    Vis.Entities(position, aim_distance, deflectors);

                                    var d_squared = distance * distance;

                                    foreach(var deflector in deflectors)
                                    {
                                        if(deflector.SqrDistance(weapon.Position) < d_squared)
                                        {
                                            deflection = true;

                                            break;
                                        }
                                    }

                                    Pool.FreeUnmanaged<BaseEntity>(ref deflectors);
                                }

around line 817:

                   bool flying = true;

                    // Facepunch removed Pool.GetList<T>() (CS0117). Use Pool.Get<List<T>>() instead.
                    var entities = Pool.Get<List<BaseEntity>>();

                    Vis.Entities(position, sensitivity_hi, entities);

around line 849:  

                       default:

                            // Facepunch removed BaseHelicopterVehicle (CS0246). Replacement is
                            // PlayerHelicopter (minicopter / scrap heli / attack heli). That type
                            // now inherits BaseVehicle, so it MUST be tested first: the old
                            // BaseHelicopterVehicle branch skipped the distance gate. If we left
                            // it after `is BaseVehicle`, player helis would take the tighter
                            // sensitivity_lo check and false-flag gravity near a heli.
                            if((entity is PlayerHelicopter) || (entity is SupplyDrop) || (entity is TreeEntity))
                            {
                                flying = false;
                            }
                            else if((entity is BaseVehicle) || (entity is BaseVehicleSeat))
                            {
                                if(player.Distance(entity.bounds.ClosestPoint(position)) <= sensitivity_lo)
                                {
                                    flying = false;
                                }
                            }
                            else if(entity.ShortPrefabName == "ladder.wooden.wall")
                            {
                                if(player.Distance(entity.bounds.ClosestPoint(position)) <= sensitivity_md)
                                {
                                    flying = false;
                                }
                            }
                            else
                            {
                                var top = entity.bounds.max.y;

                                if((position.y >= top) && ((position.y - top) <= sensitivity_lo))
                                {
                                    var bot = new Vector3(position.x, position.y - sensitivity_lo, position.z);

                                    if(Physics.CheckCapsule(position, bot, 0.25f))
                                    {
                                        flying = false;
                                    }
                                }
                            }

                            break;
                        }

                        if(!flying)
                        {
                            break;
                        }
                    }

                    if(flying && (entities.Count == 0) && Vis.AnyColliders(position, sensitivity_lo))
                    {
                        flying = false;
                    }

                    // Pair of Get<List<T>> above. FreeList is gone; FreeUnmanaged<T> is the current return path.
                    Pool.FreeUnmanaged<BaseEntity>(ref entities);

                    return flying;
                }

(the above pool.freeunmanage change ends before: "public static void Scan()")

around like 6199: 

               public static bool IsNearby(Vector3 position, bool check_privilege = true)
                {
                    // Facepunch removed Pool.GetList<T>() (CS0117). Use Pool.Get<List<T>>() instead.
                    var blocks = Pool.Get<List<BuildingBlock>>();

                    Vis.Entities(position, 16.0f, blocks, Layers.Mask.Construction, QueryTriggerInteraction.Ignore);

                    bool nearby = false;

                    foreach(var block in blocks)
                    {
                        if(check_privilege)
                        {
                            if(HasPrivilege(block))
                            {
                                nearby = true; break;
                            }
                        }
                        else
                        {
                            nearby = true; break;
                        }
                    }

                    Pool.FreeUnmanaged<BuildingBlock>(ref blocks);

                    return nearby;
                }
            }

around line 6298:

            public class Entities
            {
                public static bool InRange(Vector3 position, float radius = 3.0f)
                {
                    // Facepunch removed Pool.GetList<T>() / Pool.FreeList (CS0117).
                    var entities = Pool.Get<List<DecayEntity>>();

                    Vis.Entities(position, radius, entities);

                    bool nearby = entities.Count > 0;

                    Pool.FreeUnmanaged<DecayEntity>(ref entities);

                    return nearby;
                }
            }

around line 9709:

               attacker.MovePosition(position);

                // Facepunch removed BasePlayer.ClientRPCPlayer (CS1061). Current RPC path is
                // ClientRPC(RpcTarget.Player(rpcName, connectionPlayer), args...). Matches
                // vanilla VehicleSpawner.NudgePlayersInRadius ForcePositionTo usage.
                // Old: attacker.ClientRPCPlayer(null, attacker, "ForcePositionTo", position);
                attacker.ClientRPC(RpcTarget.Player("ForcePositionTo", attacker), position);

                attacker.SendNetworkUpdateImmediate();

                Chat.Admin(Key.UserBanTeleported, new Dictionary<string, string>
                {
                    { "playerid", user.userid.ToString() },
                    { "playername", Text.Sanitize(user.name) },
                    { "victim", Text.Sanitize(victim.name) }
                });

Full plugin / Pastebin - Part 1: https://pastebin.com/uxWGDwV2

Full plugin / Pastebin - Part 2: https://pastebin.com/whEYdxt0