Re: [PATCH 2/2] PR debug/63240 Add DWARF representation for C++11 defaulted member function.

[Jason Merrill <jason at redhat dot com>]

On 10/03/2014 09:12 AM, Mark Wielaard wrote:
> A debugger not knowing whether a special member function was explicitly
> defaulted, implicitly declared or explicitly defined seems less confusion
> than not knowing whether it was deleted. But there are some subtle cases
> where knowing whether a constructor was user defined or explicitly
> defaulted do matter for whether the default constructor might have been
> implicitly generated.

Can you elaborate?

> So like the deleted case this patch introduces
> a new attribute DW_AT_GNU_defaulted that gets attached to the function
> declaration. Note that since this is for declarations we explicitly
> test for DECL_DEFAULTED_IN_CLASS_P and ignore any implementation
> definitions that use = default; outside the class body.

Hmm, I'm dubious about this choice.  How do you expect a consumer to use 
this information?

Jason