From: Jason Merrill <jason@redhat.com>
To: Matthias Kretz <m.kretz@gsi.de>, gcc-patches@gcc.gnu.org
Cc: libstdc++@gcc.gnu.org
Subject: Re: [PATCH] Add gnu::diagnose_as attribute
Date: Tue, 22 Jun 2021 16:12:42 -0400 [thread overview]
Message-ID: <e30fc933-f1c5-0baa-691c-4ba0b726e2c6@redhat.com> (raw)
In-Reply-To: <8436091.EvYhyI6sBW@minbar>
On 6/22/21 4:01 PM, Matthias Kretz wrote:
> On Tuesday, 22 June 2021 21:52:16 CEST Jason Merrill wrote:
>> For alias templates, you probably want the attribute only on the
>> templated class, not on the instantiations.
>
> Oh good point. My current patch does not allow the attribute on alias
> templates. Consider:
>
> template <class T, class U>
> struct X {};
>
> template <class T>
> using foo [[gnu::diagnose_as]] = X<T, int>;
>
> I have no idea how this could work. I would have to set the attribute for an
> implicit partial specialization (not that I know of the existence of such a
> thing)? I.e. X<int, int> would have to be diagnosed as foo<int>, but X<int,
> float> would have to be diagnosed as X<int, float>, not foo.
>
> So if anything it should only support alias templates if they are strictly
> "renaming" the type. I.e. their template parameters must match up exactly. Can
> I constrain the attribute like this?
Yes. You can check that with get_underlying_template.
Or you could support the above by putting the attribute on the
instantiation with the TEMPLATE_INFO for foo<A> rather than a simple name.
Jason
next prev parent reply other threads:[~2021-06-22 20:12 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <14205410.xuKvIAzr1H@excalibur>
[not found] ` <20210427094648.GL3008@redhat.com>
2021-05-04 11:13 ` Matthias Kretz
2021-05-04 13:34 ` David Malcolm
2021-05-04 14:23 ` Matthias Kretz
2021-05-04 14:32 ` Matthias Kretz
2021-05-04 19:00 ` David Malcolm
2021-05-04 19:22 ` Matthias Kretz
2021-05-14 16:05 ` Martin Sebor
2021-05-26 21:33 ` Matthias Kretz
2021-05-27 17:39 ` Jason Merrill
2021-05-27 18:54 ` Matthias Kretz
2021-05-27 21:15 ` Jason Merrill
2021-05-27 22:07 ` Matthias Kretz
2021-05-28 3:05 ` Jason Merrill
2021-05-28 7:42 ` Matthias Kretz
2021-06-01 19:12 ` Jason Merrill
2021-06-01 21:01 ` Matthias Kretz
2021-06-11 10:01 ` Matthias Kretz
2021-06-15 15:51 ` Jason Merrill
2021-06-15 20:56 ` Matthias Kretz
2021-06-16 0:48 ` Jason Merrill
2021-06-22 7:30 ` Matthias Kretz
2021-06-22 19:52 ` Jason Merrill
2021-06-22 20:01 ` Matthias Kretz
2021-06-22 20:12 ` Jason Merrill [this message]
2021-07-01 9:28 ` Matthias Kretz
2021-07-01 15:18 ` Jason Merrill
2021-07-05 14:18 ` Matthias Kretz
2021-07-07 22:34 ` Jason Merrill
2021-07-07 8:23 ` Matthias Kretz
2021-07-08 1:19 ` Jason Merrill
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