Sebastian Redl wrote:
template<typename> void f() { int A[6]; for(auto&& x : A) ; }
Why does this compile? I don't see how any rvalue can be available in that context.
Wouldn't auto deduction make x an lvalue reference here?
Yes, x should be an lvalue reference here. The code should compile fine. I think this is a gcc bug. In a function template, auto deduction fails to deduce an lvalue reference when auto&& is initiliazed by a function return value of an lvalue reference. Minimal test case: (This code fails to be compiled.) int& identity(int& i) { return i; } template <typename = void> // Commenting this out makes compilation succeed void f() { int i = 0; auto&& x = identity(i); // In a function template, auto deduction fails } int main (int argc, char* argv[]) { f(); return 0; } Regards, Michel