--- a/src/cargopacket.h	Thu Aug 30 19:20:15 2007 +0000
+++ b/src/cargopacket.h	Thu Aug 30 20:40:33 2007 +0000
@@ -43,7 +43,7 @@
 	 * Is this a valid cargo packet ?
 	 * @return true if and only it is valid
 	 */
-	bool IsValid() const { return this->count != 0; }
+	inline bool IsValid() const { return this->count != 0; }
 
 	/**
 	 * Checks whether the cargo packet is from (exactly) the same source

--- a/src/depot.h	Thu Aug 30 19:20:15 2007 +0000
+++ b/src/depot.h	Thu Aug 30 20:40:33 2007 +0000
@@ -23,7 +23,7 @@
 	Depot(TileIndex xy = 0) : xy(xy) {}
 	~Depot();
 
-	bool IsValid() const { return this->xy != 0; }
+	inline bool IsValid() const { return this->xy != 0; }
 };
 
 static inline bool IsValidDepotID(DepotID index)

--- a/src/engine.h	Thu Aug 30 19:20:15 2007 +0000
+++ b/src/engine.h	Thu Aug 30 20:40:33 2007 +0000
@@ -284,7 +284,7 @@
 	EngineRenew(EngineID from = INVALID_ENGINE, EngineID to = INVALID_ENGINE) : from(from), to(to), next(NULL) {}
 	~EngineRenew() { this->from = INVALID_ENGINE; }
 
-	bool IsValid() const { return this->from != INVALID_ENGINE; }
+	inline bool IsValid() const { return this->from != INVALID_ENGINE; }
 };
 
 #define FOR_ALL_ENGINE_RENEWS_FROM(er, start) for (er = GetEngineRenew(start); er != NULL; er = (er->index + 1U < GetEngineRenewPoolSize()) ? GetEngineRenew(er->index + 1U) : NULL) if (er->IsValid())

--- a/src/industry.h	Thu Aug 30 19:20:15 2007 +0000
+++ b/src/industry.h	Thu Aug 30 20:40:33 2007 +0000
@@ -123,7 +123,7 @@
 	Industry(TileIndex tile = 0) : xy(tile) {}
 	~Industry();
 
-	bool IsValid() const { return this->xy != 0; }
+	inline bool IsValid() const { return this->xy != 0; }
 };
 
 struct IndustryTileTable {

--- a/src/oldpool.h	Thu Aug 30 19:20:15 2007 +0000
+++ b/src/oldpool.h	Thu Aug 30 20:40:33 2007 +0000
@@ -225,15 +225,6 @@
 	{
 	}
 
-	/**
-	 * Is this a valid object or not?
-	 * @return true if and only if it is valid
-	 */
-	virtual bool IsValid() const
-	{
-		return false;
-	}
-
 private:
 	/**
 	 * Allocate a pool item; possibly allocate a new block in the pool.

--- a/src/order.h	Thu Aug 30 19:20:15 2007 +0000
+++ b/src/order.h	Thu Aug 30 20:40:33 2007 +0000
@@ -107,7 +107,11 @@
 	Order() : refit_cargo(CT_NO_REFIT) {}
 	~Order() { this->type = OT_NOTHING; }
 
-	bool IsValid() const;
+	/**
+	 * Check if a Order really exists.
+	 */
+	inline bool IsValid() const { return this->type != OT_NOTHING; }
+
 	void Free();
 	void FreeChain();
 };
@@ -140,14 +144,6 @@
 	return GetOrderPoolSize();
 }
 
-/**
- * Check if a Order really exists.
- */
-inline bool Order::IsValid() const
-{
-	return this->type != OT_NOTHING;
-}
-
 inline void Order::Free()
 {
 	this->type  = OT_NOTHING;

--- a/src/signs.h	Thu Aug 30 19:20:15 2007 +0000
+++ b/src/signs.h	Thu Aug 30 20:40:33 2007 +0000
@@ -26,7 +26,7 @@
 	/** Destroy the sign */
 	~Sign();
 
-	bool IsValid() const { return this->str != STR_NULL; }
+	inline bool IsValid() const { return this->str != STR_NULL; }
 };
 
 enum {

--- a/src/station.cpp	Thu Aug 30 19:20:15 2007 +0000
+++ b/src/station.cpp	Thu Aug 30 20:40:33 2007 +0000
@@ -237,14 +237,6 @@
 	return (had_vehicle_of_type & HVOT_BUOY) != 0;
 }
 
-/** Determines whether a station exists
- * @todo replace 0 by INVALID_TILE
- */
-bool Station::IsValid() const
-{
-	return xy != 0;
-}
-
 
 /************************************************************************/
 /*                     StationRect implementation                       */
@@ -437,12 +429,6 @@
 	xy = 0;
 }
 
-/** Determines whether a RoadStop is a valid (i.e. existing) one */
-bool RoadStop::IsValid() const
-{
-	return xy != 0;
-}
-
 /** Checks whether there is a free bay in this road stop */
 bool RoadStop::HasFreeBay() const
 {

--- a/src/station.h	Thu Aug 30 19:20:15 2007 +0000
+++ b/src/station.h	Thu Aug 30 20:40:33 2007 +0000
@@ -65,7 +65,11 @@
 	RoadStop(TileIndex tile = 0);
 	virtual ~RoadStop();
 
-	bool IsValid() const;
+	/**
+	 * Determines whether a road stop exists
+	 * @return true if and only is the road stop exists
+	 */
+	inline bool IsValid() const { return this->xy != 0; }
 
 	/* For accessing status */
 	bool HasFreeBay() const;
@@ -175,7 +179,12 @@
 	uint GetPlatformLength(TileIndex tile, DiagDirection dir) const;
 	uint GetPlatformLength(TileIndex tile) const;
 	bool IsBuoy() const;
-	bool IsValid() const;
+
+	/**
+	 * Determines whether a station exists
+	 * @return true if and only is the station exists
+	 */
+	inline bool IsValid() const { return this->xy != 0; }
 };
 
 enum StationType {

--- a/src/town.h	Thu Aug 30 19:20:15 2007 +0000
+++ b/src/town.h	Thu Aug 30 20:40:33 2007 +0000
@@ -159,7 +159,7 @@
 	/** Destroy the town */
 	~Town();
 
-	bool IsValid() const { return this->xy != 0; }
+	inline bool IsValid() const { return this->xy != 0; }
 };
 
 struct HouseSpec {

--- a/src/waypoint.cpp	Thu Aug 30 19:20:15 2007 +0000
+++ b/src/waypoint.cpp	Thu Aug 30 20:40:33 2007 +0000
@@ -418,12 +418,6 @@
 	this->xy = 0;
 }
 
-bool Waypoint::IsValid() const
-{
-	return this->xy != 0;
-}
-
-
 /**
  * Fix savegames which stored waypoints in their old format
  */

--- a/src/waypoint.h	Thu Aug 30 19:20:15 2007 +0000
+++ b/src/waypoint.h	Thu Aug 30 20:40:33 2007 +0000
@@ -30,7 +30,7 @@
 	Waypoint(TileIndex tile = 0);
 	~Waypoint();
 
-	bool IsValid() const;
+	inline bool IsValid() const { return this->xy != 0; }
 };
 
 static inline bool IsValidWaypointID(WaypointID index)