[PATCH] SemaCXX: Support templates in availability attributes

[Manman Ren via cfe-commits]

> On Feb 8, 2016, at 8:17 PM, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote:
> 
> This patch adds support for templates in availability attributes.
>  - If the context for an availability diagnostic is a
>    `FunctionTemplateDecl`, look through it to the `FunctionDecl`.

>  AvailabilityResult Decl::getAvailability(std::string *Message) const {
> +  if (auto *FTD = dyn_cast<FunctionTemplateDecl>(this))
> +    return FTD->getTemplatedDecl()->getAvailability(Message);
> +
>    AvailabilityResult Result = AR_Available;

This looks generally correct to me.
The UnavailableAttr is attached to the FunctionDecl, not the FunctionTemplateDecl, so looking through sounds right.

>  - Add `__has_feature(attribute_availability_in_templates)`.
> 
> Is there anything else I should be testing to be sure availability
> works correctly in templates?

Maybe
test<UnavailableClass>()
calling unavailable function from an unavailable template function
calling an unavailable template function

I think these all work with the current compiler. But I am not sure if we have existing test coverage.

Cheers,
Manman

>  I'm working on a patch to add
> availability markup to the libc++ headers, and this is the only
> problem I've hit so far.  Anyone have thoughts on other things I
> should test?
> 
> <0001-SemaCXX-Support-templates-in-availability-attributes.patch>