[Bug c++/57857] argument of decltype used by no return value warning

[potswa at mac dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57857

--- Comment #1 from David Krauss <potswa at mac dot com> ---
Narrowing down the cause, the statement { 0; } silences the error but {
void(0); } does not.