以下函数derefItemX()在GCC4.8-5.3上编译正常，但在CLang3.8上编译失败://!AccessoryOperations-templateargumentdependedwrapperstemplate//ForNodes/non-scopedstoragestructOperations{//!\briefDefererencewrappedordirectiterator//!//!\paramielIItemXT&-iteratortobedereferenced//!\returnItemT&-resultingreferencetemplateconst