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Date: Fri, 21 Jul 2023 23:25:40 +0000
From: Joseph Myers <joseph@codesourcery.com>
To: Michael Matz <matz@suse.de>
CC: Richard Sandiford <richard.sandiford@arm.com>, Richard Biener
	<richard.guenther@gmail.com>, <gcc-patches@gcc.gnu.org>,
	<polacek@redhat.com>, <jason@redhat.com>, <nathan@acm.org>
Subject: Re: [WIP RFC] Add support for keyword-based attributes
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On Mon, 17 Jul 2023, Michael Matz via Gcc-patches wrote:

> So, essentially you want unignorable attributes, right?  Then implement 
> exactly that: add one new keyword "__known_attribute__" (invent a better 
> name, maybe :) ), semantics exactly as with __attribute__ (including using 
> the same underlying lists in our data structures), with only one single 
> deviation: instead of the warning you give an error for unhandled 
> attributes.  Done.

Assuming you also want the better-defined standard rules about how [[]] 
attributes appertain to particular entities, rather than the different 
__attribute__ rules, that would suggest something like [[!some::attr]] for 
the case of attributes that can't be ignored but otherwise are handled 
like standard [[]] attributes.

-- 
Joseph S. Myers
joseph@codesourcery.com