Index: src/OFDictionary.m
==================================================================
--- src/OFDictionary.m
+++ src/OFDictionary.m
@@ -520,11 +520,44 @@
 
 - (int)countByEnumeratingWithState: (of_fast_enumeration_state_t *)state
 			   objects: (id *)objects
 			     count: (int)count
 {
-	OF_UNRECOGNIZED_SELECTOR
+	OFEnumerator *enumerator;
+	int i;
+
+	memcpy(&enumerator, state->extra, sizeof(enumerator));
+
+	if (enumerator == nil) {
+		void *pool = objc_autoreleasePoolPush();
+
+		enumerator = [[self keyEnumerator] retain];
+		memcpy(state->extra, &enumerator, sizeof(enumerator));
+
+		objc_autoreleasePoolPop(pool);
+	}
+
+	state->itemsPtr = objects;
+	state->mutationsPtr = (unsigned long *)self;
+
+	if (state->state == 1)
+		return 0;
+
+	for (i = 0; i < count; i++) {
+		id object = [enumerator nextObject];
+
+		if (object == nil) {
+			state->state = 1;
+			[enumerator release];
+
+			return i;
+		}
+
+		objects[i] = object;
+	}
+
+	return i;
 }
 
 #ifdef OF_HAVE_BLOCKS
 - (void)enumerateKeysAndObjectsUsingBlock:
     (of_dictionary_enumeration_block_t)block

Index: tests/OFDictionaryTests.m
==================================================================
--- tests/OFDictionaryTests.m
+++ tests/OFDictionaryTests.m
@@ -36,10 +36,11 @@
 @end
 
 @interface SimpleMutableDictionary: OFMutableDictionary
 {
 	OFMutableDictionary *_dictionary;
+	unsigned long _mutations;
 }
 @end
 
 @implementation SimpleDictionary
 - (instancetype)init
@@ -111,24 +112,10 @@
 
 - (OFEnumerator *)keyEnumerator
 {
 	return [_dictionary keyEnumerator];
 }
-
-- (OFEnumerator *)objectEnumerator
-{
-	return [_dictionary objectEnumerator];
-}
-
-- (int)countByEnumeratingWithState: (of_fast_enumeration_state_t *)state
-			   objects: (id *)objects
-			     count: (int)count
-{
-	return [_dictionary countByEnumeratingWithState: state
-						objects: objects
-						  count: count];
-}
 @end
 
 @implementation SimpleMutableDictionary
 + (void)initialize
 {
@@ -137,17 +124,40 @@
 }
 
 - (void)setObject: (id)object
 	   forKey: (id)key
 {
+	bool existed = ([_dictionary objectForKey: key] == nil);
+
 	[_dictionary setObject: object
 			forKey: key];
+
+	if (existed)
+		_mutations++;
 }
 
 - (void)removeObjectForKey: (id)key
 {
+	bool existed = ([_dictionary objectForKey: key] == nil);
+
 	[_dictionary removeObjectForKey: key];
+
+	if (existed)
+		_mutations++;
+}
+
+- (int)countByEnumeratingWithState: (of_fast_enumeration_state_t *)state
+			   objects: (id *)objects
+			     count: (int)count
+{
+	int ret = [super countByEnumeratingWithState: state
+					     objects: objects
+					       count: count];
+
+	state->mutationsPtr = &_mutations;
+
+	return ret;
 }
 @end
 
 @implementation TestsAppDelegate (OFDictionaryTests)
 - (void)dictionaryTestsWithClass: (Class)dictionaryClass