iains planned changes to this revision.
iains added a comment.
need to re-check that the intention of the paper is covered (since we currently
treat bare 'export' and 'export {}' in a similar manner).
================
Comment at: clang/lib/Sema/SemaModule.cpp:848-849
+ if (auto *FD = dyn_cast<FunctionDecl>(D)) {
+ if (FD->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
+ BadExport = true;
+ } else if (auto *VD = dyn_cast<VarDecl>(D)) {
----------------
ChuanqiXu wrote:
> ChuanqiXu wrote:
> > iains wrote:
> > > ChuanqiXu wrote:
> > > > Given P2615R1 doesn't allow explicit-instantiation in export block too.
> > > I think I must be missing something - I do not see that in the paper -
> > > please could you expand your comment?
> > See the proposed change in #[module.interface]p1 in the paper, it changed:
> >
> > ```
> > export declaration
> > ```
> >
> > to
> >
> >
> > ```
> > export named-declaration
> > ```
> >
> > And the change between the old declaration and the new named declaration is
> > in the proposed change in #[dcl.pre]p1. So it shows the special
> > declarations shouldn't be allowed after `export`.
> >
> > Also I noted it is allowed to write `export { declaration-seq_opt }` where
> > the `declaration-seq` may contain special declarations. It looks weird to
> > me. I'll try to check it and ask WG21 when necessary.
> I checked the record. And it shows that the current wording reflects the
> intention. I mean
>
> ```
> export template<> class A<int>;
> ```
>
> is not allowed. But,
>
> ```
> export { template<> class A<int> };
> ```
>
> is allowed.
>
> See the proposed change in #[module.interface]p1 in the paper, it changed:
...
> And the change between the old declaration and the new named declaration is
> in the proposed change in #[dcl.pre]p1. So it shows the special declarations
> shouldn't be allowed after `export`.
>
> Also I noted it is allowed to write `export { declaration-seq_opt }` where
> the `declaration-seq` may contain special declarations. It looks weird to me.
> I'll try to check it and ask WG21 when necessary.
Indeed that does seem to be a strange mismatch - but you are right the
introduction does mention this:
"This paper addresses CWG2443 by forbidding applying export directly to certain
meaningless declarations. Conversely, it also allows all kinds to appear with
export {}. For consistency extern "C" is given the same restrictions when used
directly."
so I think I need to recheck this patch.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D153542/new/
https://reviews.llvm.org/D153542
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