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From: "daniel.kruegler at googlemail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/55002] trailing return type is rejected in function signature
Date: Sat, 20 Oct 2012 20:24:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D55002

Daniel Kr=C3=BCgler <daniel.kruegler at googlemail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |daniel.kruegler at
                   |                            |googlemail dot com

--- Comment #2 from Daniel Kr=C3=BCgler <daniel.kruegler at googlemail dot =
com> 2012-10-20 20:24:19 UTC ---
Your issue looks invalid to me, because you are never providing a pointer to
function declarator.=20

Lets look first at your simplified example:

auto (*ff) -> int (int)

This would be an invalid function declarator, because there is (a) no param=
eter
list and (b) the return type is a function type int(int), which is never
possible. I can only assume you mean

int f(auto (*ff)(int) -> int) {
  return ff(1);
}

and this is accepted.=20

A similar defect is in your original code, where the only valid form would =
be

template<class T, size_t N> size_t=20=20=20
apply (const T (&A)[N], auto (*f)(const T (&)[N]) -> size_t)
{ return   f(A); }


which is also accepted.