https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115987
--- Comment #13 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Dan Urosu from comment #7) > Why does not warn for unwarp_1? > The mere addition of an unused template parameter triggers this warning. No it doesn't. Calling the function with a temporary triggers the warning. unwrap_1(w) has no temporary involved. unwrap_2(w, 1) creates a temporary of type int. What matters is calling the function with a temporary and returning a const reference which the compiler thinks *might* bind to the temporary. Your T& example doesn't warn because a non-const reference cannot bind to a temporary, so there's no chance it is a dangling reference to the temporary argument.
