Denis Koroskin wrote:
What's a rationale behind an issue described bug 2621?
http://d.puremagic.com/issues/show_bug.cgi?id=2621
Why isn't it allowed anymore?
It broke quite a lot of my code. And while it is fixable by doing
auto tmp = someFunctionThatRetunsStruct();
someMethodThatAcceptsStructByReference(tmp);
it looks ugly and unnecessary.
Yeah, I was recently caught by this when moving some code over to D2,
thinking I'd take advantage of some const refs. I was quite surprised
when my code wouldn't compile. Consider:
struct Foo
{
int x;
Foo opAdd(const ref Foo lhs)
{
Foo f = {x + lhs.x};
return f;
}
ref Foo opAddAssign(const ref Foo lhs)
{
x += lhs.x;
return f;
}
}
Given Foo a, b and c, the following fails to compile:
c += a + b;
The work around is to add an overridden opAddAssign that takes a non-ref
foo. Not pretty, especially when dealing with numerous methods. Rather
defeats the purpose of const ref parameters, does it not? And it's far
from intuitive, particularly when coming from C++.
