// RUN: %clang_cc1 -emit-llvm -triple x86_64-apple-darwin %s -o /dev/null typedef unsigned int size_t; @protocol P @end @interface NSMutableArray #if __has_feature(objc_subscripting) - (id)objectAtIndexedSubscript:(size_t)index; - (void)setObject:(id)object atIndexedSubscript:(size_t)index; #endif @end #if __has_feature(objc_subscripting) @interface XNSMutableArray - (id)objectAtIndexedSubscript:(size_t)index; - (void)setObject:(id)object atIndexedSubscript:(size_t)index; #endif @end @interface NSMutableDictionary - (id)objectForKeyedSubscript:(id)key; - (void)setObject:(id)object forKeyedSubscript:(id)key; @end @class NSString; int main(void) { NSMutableArray<P> * array; id oldObject = array[10]; array[10] = oldObject; id unknown_array; oldObject = unknown_array[1]; unknown_array[1] = oldObject; NSMutableDictionary *dictionary; NSString *key; id newObject; oldObject = dictionary[key]; dictionary[key] = newObject; // replace oldObject with newObject }