Index: src/OFCharacterSet_bitset.m
==================================================================
--- src/OFCharacterSet_bitset.m
+++ src/OFCharacterSet_bitset.m
@@ -20,10 +20,15 @@
 #import "OFString.h"
 
 #import "OFOutOfRangeException.h"
 
 @implementation OFCharacterSet_bitset
+- (instancetype)init
+{
+	OF_INVALID_INIT_METHOD
+}
+
 - (instancetype)initWithCharactersInString: (OFString *)string
 {
 	self = [super init];
 
 	@try {

Index: src/OFCharacterSet_invertedSet.m
==================================================================
--- src/OFCharacterSet_invertedSet.m
+++ src/OFCharacterSet_invertedSet.m
@@ -20,10 +20,15 @@
 #import "OFString.h"
 
 #import "OFOutOfRangeException.h"
 
 @implementation OFCharacterSet_invertedSet
+- (instancetype)init
+{
+	OF_INVALID_INIT_METHOD
+}
+
 - (instancetype)of_initWithCharacterSet: (OFCharacterSet *)characterSet
 {
 	self = [super init];
 
 	_characterSet = [characterSet retain];

Index: src/OFCharacterSet_range.m
==================================================================
--- src/OFCharacterSet_range.m
+++ src/OFCharacterSet_range.m
@@ -20,10 +20,15 @@
 #import "OFString.h"
 
 #import "OFOutOfRangeException.h"
 
 @implementation OFCharacterSet_range
+- (instancetype)init
+{
+	OF_INVALID_INIT_METHOD
+}
+
 - (instancetype)initWithRange: (of_range_t)range
 {
 	self = [super init];
 
 	@try {