The warning below is unhelpful in generic code and silencing it by removing
the top-level cv qualifiers is unnecessarily tedious.

$ cat t.cpp && g++ t.cpp -W
template <class T>
T foo () { return T (); }

int main ()
{
    foo<const int>();
}
t.cpp: In function 'int main()':
t.cpp:2: warning: type qualifiers ignored on function return type