Index: src/OFArray.h
==================================================================
--- src/OFArray.h
+++ src/OFArray.h
@@ -294,13 +294,10 @@
  */
 - (id)foldUsingBlock: (of_array_fold_block_t)block;
 #endif
 @end
 
-@interface OFArray_placeholder: OFArray
-@end
-
 @interface OFArrayEnumerator: OFEnumerator
 {
 	OFArray	      *array;
 	size_t	      count;
 	unsigned long mutations;

Index: src/OFArray.m
==================================================================
--- src/OFArray.m
+++ src/OFArray.m
@@ -33,10 +33,13 @@
 #import "macros.h"
 
 static struct {
 	Class isa;
 } placeholder;
+
+@interface OFArray_placeholder: OFArray
+@end
 
 @implementation OFArray_placeholder
 - init
 {
 	return (id)[[OFArray_adjacent alloc] init];

Index: src/OFCountedSet.h
==================================================================
--- src/OFCountedSet.h
+++ src/OFCountedSet.h
@@ -41,8 +41,5 @@
  */
 - (void)enumerateObjectsAndCountUsingBlock:
     (of_counted_set_enumeration_block_t)block;
 #endif
 @end
-
-@interface OFCountedSet_placeholder: OFCountedSet
-@end

Index: src/OFCountedSet.m
==================================================================
--- src/OFCountedSet.m
+++ src/OFCountedSet.m
@@ -26,10 +26,13 @@
 #import "OFNotImplementedException.h"
 
 static struct {
 	Class isa;
 } placeholder;
+
+@interface OFCountedSet_placeholder: OFCountedSet
+@end
 
 @implementation OFCountedSet_placeholder
 - init
 {
 	return (id)[[OFCountedSet_hashtable alloc] init];

Index: src/OFDictionary.h
==================================================================
--- src/OFDictionary.h
+++ src/OFDictionary.h
@@ -217,9 +217,6 @@
 - _initWithDictionary: (OFDictionary*)dictionary
 	     copyKeys: (BOOL)copyKeys;
 #endif
 @end
 
-@interface OFDictionary_placeholder: OFDictionary
-@end
-
 #import "OFMutableDictionary.h"

Index: src/OFDictionary.m
==================================================================
--- src/OFDictionary.m
+++ src/OFDictionary.m
@@ -28,10 +28,13 @@
 #import "OFNotImplementedException.h"
 
 static struct {
 	Class isa;
 } placeholder;
+
+@interface OFDictionary_placeholder: OFDictionary
+@end
 
 @implementation OFDictionary_placeholder
 - init
 {
 	return (id)[[OFDictionary_hashtable alloc] init];

Index: src/OFMutableArray.h
==================================================================
--- src/OFMutableArray.h
+++ src/OFMutableArray.h
@@ -123,8 +123,5 @@
 /**
  * \brief Converts the mutable array to an immutable array.
  */
 - (void)makeImmutable;
 @end
-
-@interface OFMutableArray_placeholder: OFMutableArray
-@end

Index: src/OFMutableArray.m
==================================================================
--- src/OFMutableArray.m
+++ src/OFMutableArray.m
@@ -30,10 +30,13 @@
 #import "macros.h"
 
 static struct {
 	Class isa;
 } placeholder;
+
+@interface OFMutableArray_placeholder: OFMutableArray
+@end
 
 @implementation OFMutableArray_placeholder
 - init
 {
 	return (id)[[OFMutableArray_adjacent alloc] init];

Index: src/OFMutableDictionary.h
==================================================================
--- src/OFMutableDictionary.h
+++ src/OFMutableDictionary.h
@@ -54,8 +54,5 @@
 /**
  * \brief Converts the mutable dictionary to an immutable dictionary.
  */
 - (void)makeImmutable;
 @end
-
-@interface OFMutableDictionary_placeholder: OFDictionary
-@end

Index: src/OFMutableDictionary.m
==================================================================
--- src/OFMutableDictionary.m
+++ src/OFMutableDictionary.m
@@ -22,10 +22,13 @@
 #import "OFNotImplementedException.h"
 
 static struct {
 	Class isa;
 } placeholder;
+
+@interface OFMutableDictionary_placeholder: OFDictionary
+@end
 
 @implementation OFMutableDictionary_placeholder
 - init
 {
 	return (id)[[OFMutableDictionary_hashtable alloc] init];

Index: src/OFMutableSet.h
==================================================================
--- src/OFMutableSet.h
+++ src/OFMutableSet.h
@@ -59,8 +59,5 @@
 /**
  * \brief Converts the mutable set to an immutable set.
  */
 - (void)makeImmutable;
 @end
-
-@interface OFMutableSet_placeholder: OFMutableSet
-@end

Index: src/OFMutableSet.m
==================================================================
--- src/OFMutableSet.m
+++ src/OFMutableSet.m
@@ -25,10 +25,13 @@
 #import "OFNotImplementedException.h"
 
 static struct {
 	Class isa;
 } placeholder;
+
+@interface OFMutableSet_placeholder: OFMutableSet
+@end
 
 @implementation OFMutableSet_placeholder
 - init
 {
 	return (id)[[OFMutableSet_hashtable alloc] init];

Index: src/OFSet.h
==================================================================
--- src/OFSet.h
+++ src/OFSet.h
@@ -131,9 +131,6 @@
  */
 - (OFSet*)filteredSetUsingBlock: (of_set_filter_block_t)block;
 #endif
 @end
 
-@interface OFSet_placeholder: OFSet
-@end
-
 #import "OFMutableSet.h"

Index: src/OFSet.m
==================================================================
--- src/OFSet.m
+++ src/OFSet.m
@@ -25,10 +25,13 @@
 #import "OFNotImplementedException.h"
 
 static struct {
 	Class isa;
 } placeholder;
+
+@interface OFSet_placeholder: OFSet
+@end
 
 @implementation OFSet_placeholder
 - init
 {
 	return (id)[[OFSet_hashtable alloc] init];