diff --git a/src/collision.cpp b/src/collision.cpp
index 673966b6e..7f330f7cc 100644
--- a/src/collision.cpp
+++ b/src/collision.cpp
@@ -298,7 +298,8 @@ collisionMoveResult collisionMoveSimple(Environment *env, IGameDef *gamedef,
 			f32 distance = speed_f.getLength();
 			std::vector<DistanceSortedActiveObject> clientobjects;
 			c_env->getActiveObjects(pos_f,distance * 1.5,clientobjects);
-			for (int i=0; i < clientobjects.size(); i++)
+			for (std::vector<DistanceSortedActiveObject>::size_type i=0;
+			     i < clientobjects.size(); i++)
 			{
 				if ((self == 0) || (self != clientobjects[i].obj)) {
 					objects.push_back((ActiveObject*)clientobjects[i].obj);
diff --git a/src/mapgen.h b/src/mapgen.h
index 17136a137..37cb88f9c 100644
--- a/src/mapgen.h
+++ b/src/mapgen.h
@@ -75,6 +75,7 @@ struct MapgenParams {
 	
 	virtual bool readParams(Settings *settings) = 0;
 	virtual void writeParams(Settings *settings) {};
+	virtual ~MapgenParams() {};
 };
 
 class Mapgen {
@@ -94,6 +95,7 @@ public:
 
 	virtual void makeChunk(BlockMakeData *data) {};
 	virtual int getGroundLevelAtPoint(v2s16 p) = 0;
+	virtual ~Mapgen() {};
 
 	//Legacy functions for Farmesh (pending removal)
 	static bool get_have_beach(u64 seed, v2s16 p2d);
@@ -105,6 +107,7 @@ struct MapgenFactory {
 	virtual Mapgen *createMapgen(int mgid, MapgenParams *params,
 								 EmergeManager *emerge) = 0;
 	virtual MapgenParams *createMapgenParams() = 0;
+	virtual ~MapgenFactory() {};
 };
 
 enum OreType {
@@ -144,6 +147,7 @@ public:
 	void placeOre(Mapgen *mg, u32 blockseed, v3s16 nmin, v3s16 nmax);
 	virtual void generate(ManualMapVoxelManipulator *vm, int seed,
 						u32 blockseed, v3s16 nmin, v3s16 nmax) = 0;
+	virtual ~Ore() {};
 };
 
 class OreScatter : public Ore {
diff --git a/src/noise.h b/src/noise.h
index ace6d7eb4..0088ed0c4 100644
--- a/src/noise.h
+++ b/src/noise.h
@@ -88,7 +88,7 @@ public:
 
 	Noise(NoiseParams *np, int seed, int sx, int sy);
 	Noise(NoiseParams *np, int seed, int sx, int sy, int sz);
-	~Noise();
+	virtual ~Noise();
 
 	virtual void init(NoiseParams *np, int seed, int sx, int sy, int sz);
 	void setSize(int sx, int sy);
diff --git a/src/test.cpp b/src/test.cpp
index d1f53f880..43922103b 100644
--- a/src/test.cpp
+++ b/src/test.cpp
@@ -464,7 +464,7 @@ struct TestCompress: public TestBase
 			std::string str_decompressed = os_decompressed.str();
 			UTEST(str_decompressed.size() == data_in.size(), "Output size not"
 					" equal (output: %u, input: %u)",
-					str_decompressed.size(), data_in.size());
+					unsigned (str_decompressed.size()), unsigned (data_in.size()));
 			for(u32 i=0; i<size && i<str_decompressed.size(); i++){
 				UTEST(str_decompressed[i] == data_in[i],
 						"index out[%i]=%i differs from in[%i]=%i",