Re: [PATCH 2/2] c++: remove lookup_template_class's entering_scope flag

[Jason Merrill <jason@redhat.com>]

On 5/1/24 13:40, Patrick Palka wrote:
> On Wed, 1 May 2024, Jason Merrill wrote:
> 
>> On 5/1/24 12:41, Patrick Palka wrote:
>>> On Fri, 2 Feb 2024, Patrick Palka wrote:
>>>
>>>> Bootstrapped and regtested on x86_64-pc-linux, does this look like
>>>> an improvement?  This is not a bugfix and barely related to the previous
>>>> patch, but the previous patch's new use of entering_scope=true motivated
>>>> me to submit this patch since it seems like a nice simplification.
>>>
>>> Ping, now that stage 1 is open.
>>
>> Thanks for the ping.  The earlier message isn't showing up in Thunderbird for
>> some reason, though I see it in the gmail web interface...
> 
> Ah, weird.  No worries, this patch was very much stage 1 material anyway.
> 
>>
>>>> @@ -16771,9 +16722,10 @@ tsubst (tree t, tree args, tsubst_flags_t
>>>> complain, tree in_decl)
>>>>    	    ctx = TREE_VEC_ELT (ctx, 0);
>>>>    	  }
>>>>    	else
>>>> -	  ctx = tsubst_aggr_type (ctx, args,
>>>> -				  complain | tf_qualifying_scope,
>>>> -				  in_decl, /*entering_scope=*/1);
>>>> +	  {
>>>> +	    ctx = tsubst_scope (ctx, args, complain, in_decl);
>>
>> Why is this one tsubst_scope while the others are all plain tsubst?
> 
> Ah, just because the call to tsubst_aggr_type being replace passes
> tf_qualifying_scope already, so we might as well use tsubst_scope
> as shorthand.
> 
>> Do we want a tsubst_entering_scope function?
> 
> Which is just shorthand for tsubst + adjust_type_for_entering_scope?

That's what I was thinking.

> Sure, though I was wondering if we eventually might want to get rid of
> the distinction between the primary template type A<T> and the generic
> instantiation A<T>, and we could treat this as an incremental step
> towards that (then we'd just eventually remove the
> adjust_type_for_entering_scope calls and keep the tsubst calls).

I don't think we want that; having the distinction helps to avoid 
wrongly looking up members of the primary template in contexts that 
shouldn't be able to.

Jason