Re: [PATCH] c++: concept-ids and value-dependence [PR102412]

[Patrick Palka via Gcc-patches]

On Tue, 21 Sep 2021, Jason Merrill wrote:

> On 9/21/21 09:30, Patrick Palka wrote:
> >       case TEMPLATE_ID_EXPR:
> > -      return concept_definition_p (TREE_OPERAND (expression, 0));
> > +      return concept_definition_p (TREE_OPERAND (expression, 0))
> > +   && any_dependent_template_arguments_p (TREE_OPERAND (expression, 1));
> 
> Hmm, do we even need to check concept_definition_p?  Even if other
> template-ids don't get here, if they did they would also be dependent if they
> had dependent template arguments.

Ah yeah, the concept_definition_p check doesn't seem to be needed.  IIUC
other template-ids can get here but for them we should always return
false at this point since we already checked for type-dependence earlier
in the function (which also checks a_d_t_a_p).

Though to be extra safe I'm inclined to keep the check to avoid
potentially affecting non-concepts code when backporting the patch.

> 
> OK either way.
> 
> Jason
> 
>