[cfe-dev] Partial specialization after implicit/explicit template instantiation.

[Nikola Smiljanic]

Hi Anton, and welcome! Richard (CCed) will tell us if this is indeed a
clang bug. I can give you some general comments in the meantime:

Patches that need review are sent to cfe-commits or attached to Phabricator
(code review tool we use). They mostly go unnoticed in bugzilla.

Please use clang-format to format the code.

We'll need a test for this. It's also a good practice to provide a code
sample that demonstrates the issue when reporting a bug (this is what
usually ends up being your test). Have a look at existing test
infrastructure, namely -verify switch and expected-error "annotation". The
test should probably go to test/SemaTemplate/temp_class_spec.cpp

auto const ThisPartialSpec should be const auto *ThisPartialSpec

auto InstantiatedFrom should be auto *InstantiatedFrom

Other than that your code looks good, but I can't really comment on the
logic.

Nikola


On Tue, Oct 7, 2014 at 11:45 PM, Anton Bikineev <ant.bikineev at gmail.com>
wrote:

> Hi all,
>
> I'm sorry to partially duplicate this post from cfe-commits,
> but probably that was wrong place to ask this question.
>
> I recently found that Clang doesn't behave similiar as GCC
> in case of partial specialization ater implicit or explicit
> specialization of class template. GCC gives diagnostic like
>
> "error: partial specialization of 'A<const T*>' after instantiation of
> 'A<const char*>'"
>
> while Clang just ignores it and instantiates previously declared
> templates by lookup. I looked over the Standard and found:
>
> C++ [temp.class.spec]p1:
> "A partial specialization shall be declared before the first
> use of a class template specialization that would make use of
> the partial specialization as the result of an implicit or explicit
> instantiation in every translation unit in which such a use occurs;
> no diagnostic is required."
>
> So it seems to me that GCC has a right behaviour for this. I also
> submitted a bug http://llvm.org/bugs/show_bug.cgi?id=21156 and
> wrote a patch, which I attached to bug. I just was wondering,
> does this patch really make sense? I'm newbie in Clang and my code
> may be incorrect but I would be extremely thankful if someone
> could review it (if it really makes sense).
>
> I'm also not sure, probably Clang has its own politics for this.
> If so, what is a reason of such behavior?
>
>
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20141008/6008a691/attachment.html>