[PATCH] D27486: Correct class-template deprecation behavior

[Erich Keane via Phabricator via cfe-commits]

erichkeane added a comment.

Thanks for the feedback Richard!  I'll look into whether instantiating the full attribute set upon creation is a possibility.



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Comment at: include/clang/Basic/Attr.td:301
   bit DuplicatesAllowedWhileMerging = 0;
+  // Set to true if this attribute should apply to template declarations,
+  // remains false if this should only be applied to the definition.
----------------
rsmith wrote:
> I find this confusing -- it seems to suggest the attribute would be applied to the template declaration, not the templated declaration. I also think that the property we're modelling here is something more general than something about templates -- rather, I think the property is "is this attribute only meaningful when applied to / inherited into a defintiion?" It would also be useful to make clear that this only applies to class templates; for function templates, we always instantiate all the attributes with the declaration.
> 
> Looking through our current attribute set, it looks like at least `AbiTag` should also get this set, and maybe also `Visibility`. (Though I wonder if there would be any problem with always instantiating the full attribute set for a class declaration.)
> (Though I wonder if there would be any problem with always instantiating the full attribute set for a class declaration.)

This is definitely a good point.  It seems that just about every other usage of instantiating attributes happens right after creation, class template specialization is the lone exception it seems.

If I were to simply revert most of this change, then alter my SemaTemplate.cpp changes to just call InstantiateAttrs and presumably remove the other call to InstantiateAttrs (since it results in 2 sets of attributes), would you consider that to be more acceptable?





https://reviews.llvm.org/D27486