Index: src/OFMutableArray.h
==================================================================
--- src/OFMutableArray.h
+++ src/OFMutableArray.h
@@ -107,10 +107,21 @@
  * @param index The index of the object to replace
  * @param object The replacement object
  */
 - (void)replaceObjectAtIndex: (size_t)index
 		  withObject: (ObjectType)object;
+
+/*!
+ * @brief Replaces the object at the specified index with the specified object.
+ *
+ * This method is the same as @ref replaceObjectAtIndex:withObject:.
+ *
+ * This method is also used by the subscripting syntax.
+ *
+ * @param index The index of the object to replace
+ * @param object The replacement object
+ */
 -    (void)setObject: (ObjectType)object
   atIndexedSubscript: (size_t)index;
 
 /*!
  * @brief Replaces the first object that has the same address as the specified

Index: src/OFMutableDictionary.h
==================================================================
--- src/OFMutableDictionary.h
+++ src/OFMutableDictionary.h
@@ -61,18 +61,30 @@
 - (instancetype)initWithCapacity: (size_t)capacity;
 
 /*!
  * @brief Sets an object for a key.
  *
- * A key can be any object that conforms to the OFCopying protocol.
+ * A key can be any object that conforms to the @ref OFCopying protocol.
  *
  * @param key The key to set
  * @param object The object to set the key to
  */
 - (void)setObject: (ObjectType)object
 	   forKey: (KeyType)key;
--   (void)setObject: (ObjectType)object
+
+/*!
+ * @brief Sets an object for a key.
+ *
+ * A key can be any object that conforms to the @ref OFCopying protocol.
+ *
+ * This method is also used by the subscripting syntax.
+ *
+ * @param key The key to set
+ * @param object The object to set the key to. If it is nil, this is equal to
+ *		 calling @ref removeObjectForKey:.
+ */
+-   (void)setObject: (nullable ObjectType)object
   forKeyedSubscript: (KeyType)key;
 
 /*!
  * @brief Removes the object for the specified key from the dictionary.
  *

Index: src/OFMutableDictionary.m
==================================================================
--- src/OFMutableDictionary.m
+++ src/OFMutableDictionary.m
@@ -168,12 +168,15 @@
 }
 
 -   (void)setObject: (id)object
   forKeyedSubscript: (id)key
 {
-	[self setObject: object
-		 forKey: key];
+	if (object != nil)
+		[self setObject: object
+			 forKey: key];
+	else
+		[self removeObjectForKey: key];
 }
 
 - (void)removeObjectForKey: (id)key
 {
 	OF_UNRECOGNIZED_SELECTOR