Re: C++ PATCH to add auto return type deduction with -std=c++1y

[Marc Glisse <marc dot glisse at inria dot fr>]

On Wed, 28 Mar 2012, Gabriel Dos Reis wrote:

> On Wed, Mar 28, 2012 at 10:51 AM, Marc Glisse <marc.glisse@inria.fr> wrote:
> > On Sun, 25 Mar 2012, Marc Glisse wrote:
> >
> > > - a first goal is simple functions, with a single return statement (which
> > > may even often be the only statement).
> >
> >
> > After playing with it a bit, I am not sure how to use it in the simple
> > forwarding case:
> >
> > T f(int);
> > auto g(int i){return f(i);}
>
> function call or return value is equivalent to initialization. So, the
> deduction works (as it should) as if you wrote
>
>    auto x = f(i);

I agree that it works like initialization, and like lambdas, so that ship 
has sailed. I assume there were good reasons for that, even if they are 
not obvious, I know things can be trickier than they appear. However, I 
can't help thinking that there is something wrong with having to write:

auto g(int i) -> decltype(f(i)) { return f(i); }

(and even worse with noexcept(noexcept(f(i))), but that's another issue)
for a simple macro-like forwarding function.

Now fixing that isn't the goal of Jason's proposal and this is fine.

--
Marc Glisse