[cxx-abi-dev] Transfer modes for parameters and return values

[John McCall]

On May 7, 2014, at 11:35 AM, Richard Smith <richardsmith at google.com> wrote:
> On 7 May 2014 11:23, "John McCall" <rjmccall at apple.com> wrote:
> > I’d be okay with the rule “if the type has a non-trivial copy constructor, move constructor, or destructor, or if all its copy and move constructors are declared as deleted”.
> 
> I could live with that (but the currently-proposed language change doesn't allow it; we'd need to remove the accessibility check there). Drop the "declared as", though - I don't think it should matter how the functions came to be deleted.

I keep forgetting that it’s illegal to retroactively delete a function.  Yes, I agree that it shouldn’t matter how the function came to be deleted.

> I think I'd also prefer to phrase this in a way that's not dependent on whether a deleted function is trivial.
> 
> "[Pass an object of class type by value if] every copy constructor and move constructor is deleted or trivial and at least one of them is not deleted, and the destructor is trivial.”

That works.

John.