[gcc r15-1295] c++: adjust comment

[Jason Merrill]

https://gcc.gnu.org/g:57113e3db168e19c46ca52ad084790d462eea603

commit r15-1295-g57113e3db168e19c46ca52ad084790d462eea603
Author: Jason Merrill <jason@redhat.com>
Date:   Wed Jun 12 21:43:45 2024 -0400

    c++: adjust comment
    
    Adjusting the comment I added in r15-1223 to clarify that this is a
    workaround for a bug elsewhere.
    
    gcc/cp/ChangeLog:
    
            * module.cc (depset::hash::add_binding_entity): Adjust comment.

Diff:
---
 gcc/cp/module.cc | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 72e876cec187..ea7ad0c1f291 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -13254,9 +13254,10 @@ depset::hash::add_binding_entity (tree decl, WMB_Flags flags, void *data_)
       if (data->hash->add_namespace_entities (decl, data->partitions))
 	{
 	  /* It contains an exported thing, so it is exported.
-	     We used to assert DECL_MODULE_PURVIEW_P, but that fails for a
-	     namespace like std::__exception_ptr which is never opened in
-	     module purview; the exporting using finds another using.  */
+
+	     FIXME we have to set DECL_MODULE_PURVIEW_P instead of asserting
+	     that it is already set because of the c++/114683 issue with
+	     exported using-declarations; see do_nonmember_using_decl.  */
 	  DECL_MODULE_PURVIEW_P (decl) = true;
 	  DECL_MODULE_EXPORT_P (decl) = true;
 	}