@@ -31,26 +31,26 @@
 
 @interface OFSet_placeholder: OFSet
 @end
 
 @implementation OFSet_placeholder
-- init
+- (instancetype)init
 {
 	return (id)[[OFSet_hashtable alloc] init];
 }
 
-- initWithSet: (OFSet *)set
+- (instancetype)initWithSet: (OFSet *)set
 {
 	return (id)[[OFSet_hashtable alloc] initWithSet: set];
 }
 
-- initWithArray: (OFArray *)array
+- (instancetype)initWithArray: (OFArray *)array
 {
 	return (id)[[OFSet_hashtable alloc] initWithArray: array];
 }
 
-- initWithObjects: (id)firstObject, ...
+- (instancetype)initWithObjects: (id)firstObject, ...
 {
 	id ret;
 	va_list arguments;
 
 	va_start(arguments, firstObject);
@@ -59,35 +59,35 @@
 	va_end(arguments);
 
 	return ret;
 }
 
-- initWithObjects: (id const *)objects
-	    count: (size_t)count
+- (instancetype)initWithObjects: (id const *)objects
+			  count: (size_t)count
 {
 	return (id)[[OFSet_hashtable alloc] initWithObjects: objects
 						      count: count];
 }
 
-- initWithObject: (id)firstObject
-       arguments: (va_list)arguments
+- (instancetype)initWithObject: (id)firstObject
+		     arguments: (va_list)arguments
 {
 	return (id)[[OFSet_hashtable alloc] initWithObject: firstObject
 						 arguments: arguments];
 }
 
-- initWithSerialization: (OFXMLElement *)element
+- (instancetype)initWithSerialization: (OFXMLElement *)element
 {
 	return (id)[[OFSet_hashtable alloc] initWithSerialization: element];
 }
 
-- retain
+- (instancetype)retain
 {
 	return self;
 }
 
-- autorelease
+- (instancetype)autorelease
 {
 	return self;
 }
 
 - (void)release
@@ -105,11 +105,11 @@
 {
 	if (self == [OFSet class])
 		placeholder.isa = [OFSet_placeholder class];
 }
 
-+ alloc
++ (instancetype)alloc
 {
 	if (self == [OFSet class])
 		return (id)&placeholder;
 
 	return [super alloc];
@@ -148,11 +148,11 @@
 {
 	return [[[self alloc] initWithObjects: objects
 					count: count] autorelease];
 }
 
-- init
+- (instancetype)init
 {
 	if (object_getClass(self) == [OFSet class]) {
 		@try {
 			[self doesNotRecognizeSelector: _cmd];
 		} @catch (id e) {
@@ -164,27 +164,27 @@
 	}
 
 	return [super init];
 }
 
-- initWithSet: (OFSet *)set
+- (instancetype)initWithSet: (OFSet *)set
 {
 	OF_INVALID_INIT_METHOD
 }
 
-- initWithArray: (OFArray *)array
+- (instancetype)initWithArray: (OFArray *)array
 {
 	OF_INVALID_INIT_METHOD
 }
 
-- initWithObjects: (id const *)objects
+- (instancetype)initWithObjects: (id const *)objects
 	    count: (size_t)count
 {
 	OF_INVALID_INIT_METHOD
 }
 
-- (id)initWithObjects: (id)firstObject, ...
+- (instancetype)initWithObjects: (id)firstObject, ...
 {
 	id ret;
 	va_list arguments;
 
 	va_start(arguments, firstObject);
@@ -193,17 +193,17 @@
 	va_end(arguments);
 
 	return ret;
 }
 
-- initWithObject: (id)firstObject
-       arguments: (va_list)arguments
+- (instancetype)initWithObject: (id)firstObject
+		     arguments: (va_list)arguments
 {
 	OF_INVALID_INIT_METHOD
 }
 
-- initWithSerialization: (OFXMLElement *)element
+- (instancetype)initWithSerialization: (OFXMLElement *)element
 {
 	OF_INVALID_INIT_METHOD
 }
 
 - (size_t)count
@@ -337,16 +337,16 @@
 	objc_autoreleasePoolPop(pool);
 
 	return ret;
 }
 
-- copy
+- (id)copy
 {
 	return [self retain];
 }
 
-- mutableCopy
+- (id)mutableCopy
 {
 	return [[OFMutableSet alloc] initWithSet: self];
 }
 
 - (bool)isSubsetOfSet: (OFSet *)set