[Bug c++/51480] non-const default argument gets rejected

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51480

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-12-09 
10:02:52 UTC ---
If you think it's useful to modify an object that will never be used, you can
do it like this:

struct A
{
};

void accepted(const A &a = A())
{
}

void rejected(A &a)
{
}

void rejected()
{
  A unused;
  rejected(unused);
}