Re: [PATCH v2] c++/reflection: ICE with &template [:members_of():] [PR124794]

On 7/31/26 12:38 PM, Marek Polacek wrote:
> On Thu, Jul 30, 2026 at 09:35:26AM -0400, Jason Merrill wrote:
>> On 7/28/26 1:34 PM, Marek Polacek wrote:
>>> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/16?
>>>
>>> -- >8 --
>>> Given
>>>
>>>     struct C { template <class T> void f(T); };
>>>
>>> we handle "&template [:^^C::f:]" correctly because the spliced
>>> expression is
>>>
>>>     BASELINK<OVERLOAD<TEMPLATE_DECL f>>, binfo C>
>>>
>>> which is fine: we have an OVERLOAD around the TEMPLATE_DECL and
>>> lookup_member wrapped the whole thing in a BASELINK.  But when
>>> we're splicing members_of(^^C, ac)[0], we ended up with
>>>
>>>     OVERLOAD<TEMPLATE_DECL f>>
>>>
>>> and then go down the wrong path in cp_parser_splice_expression.
>>>
>>> splice already correctly adds the missing OVERLOAD but it also
>>> needs to (maybe) add a BASELINK.
>>
>> Yes, though I'm nervous about the use of currently_open_derived_class in
>> baselink_for_fns.  Does that cause trouble with a splice after ->?
> 
> We test a splice after -> in e.g. member1.C and member3.C and they still pass.
> 
> And given
> 
>    struct C {
>      void g (int);
>    };
> 
>    C *pc = ...;
> 
> this
> 
>    auto a = &pc->[: ^^C::g :];
> 
> is invalid (clang++ also rejects).
> 
> ...but we don't have a test for a valid &p->[: x :] so this
> version adds it.
> 
> +void
> +g (C *pc)
> +{
> +  const int *p = &pc->[: ^^C::val :];
> +}
That tests the case where currently_open_derived_class is null, so it 
doesn't matter.  How about a case where we're in a member function of a 
class derived from C and the object argument is a different derived class?

Jason