20 General utilities library [utilities]

20.10 Metaprogramming and type traits [meta]

20.10.7 Transformations between types [meta.trans]

20.10.7.2 Reference modifications [meta.trans.ref]

Table 53 — Reference modifications
TemplateComments
template <class T>
struct remove_reference;
If T has type “reference to T1” then the member typedef type shall name T1; otherwise, type shall name T.
template <class T>
struct add_lvalue_reference;
If T names an object or function type then the member typedef type shall name T&; otherwise, if T names a type “rvalue reference to T1” then the member typedef type shall name T1&; otherwise, type shall name T.
template <class T>
struct add_rvalue_reference;
If T names an object or function type then the member typedef type shall name T&&; otherwise, type shall name T. [ Note: This rule reflects the semantics of reference collapsing ([dcl.ref]). For example, when a type T names a type T1&, the type add_rvalue_reference_t<T> is not an rvalue reference.  — end note ]