constant references with typedef and templates in c++

Question

I heard the temporary objects can only be assigned to constant references.

But this code gives error

#include     
template

        

Answer 1

To maintain consistency with the Right Left Rule, I prefer to use 'cv' qualifiers like so.

int const x = 2; // x is a const int (by applying Right Left rule)

int const *p = &x;  // p is a pinter to const int

In your example, I would write const ref error = check(); like so

ref const error = check(); // parsed as error is a const reference to an integer

As @Prasoon Saurav pointed out, cv qualifiers are ignored when introduced through typedef because as @GMan also says, that cv qualified references are ill-formed.

Therefore the declaration is effectively as below, which of course is an error.

   int &error = check(); 

Check out this for more information.