std::experimental::ranges::IndirectRelation
来自cppreference.com
                    
                                        
                    < cpp | experimental | ranges
                    
                                                            
                    |   template < class F, class I1, class I2 = I1 > concept bool IndirectRelation =  | 
(范围 TS) | |
| 本节未完成 原因:添加描述和额外通告  |