// { dg-do compile { target c++11 } } // { dg-options "-Wredundant-move" } // Define std::move. namespace std { template struct remove_reference { typedef _Tp type; }; template struct remove_reference<_Tp&> { typedef _Tp type; }; template struct remove_reference<_Tp&&> { typedef _Tp type; }; template constexpr typename std::remove_reference<_Tp>::type&& move(_Tp&& __t) noexcept { return static_cast::type&&>(__t); } } template struct T { T() { } T(const T&) { } T(T&&) { } }; template struct U { U() { } U(const U&) { } U(U&&) { } U(T) { } }; T fn1 (T t) { return t; } T fn2 (T t) { // Will use move even without std::move. return std::move (t); // { dg-warning "redundant move in return statement" } } T fn3 (const T t) { // t is const: will decay into copy. return t; } T fn4 (const T t) { // t is const: will decay into copy despite std::move, so it's redundant. // We used to warn about this, but no longer since c++/87378. // Now we warn again since c++/90428. return std::move (t); // { dg-warning "redundant move" } } int fn5 (int i) { // Not a class type. return std::move (i); } T fn6 (T t, bool b) { if (b) throw std::move (t); return std::move (t); // { dg-warning "redundant move in return statement" } } U fn7 (T t) { // Core 1579 means we'll get a move here. return t; } U fn8 (T t) { // Core 1579 means we'll get a move here. Even without std::move. return std::move (t); // { dg-warning "redundant move in return statement" } } T fn9 (T& t) { // T is a reference and the move isn't redundant. return std::move (t); } T fn10 (T&& t) { // T is a reference and the move isn't redundant. return std::move (t); }