[PATCH] D27486: Correct class-template deprecation behavior
Richard Smith via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Wed Jan 11 15:07:24 PST 2017
rsmith added inline comments.
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.
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.)
Comment at: lib/Sema/SemaTemplate.cpp:2406-2407
+ ClassTemplate->getTemplatedDecl(), Decl);
You should also presumably do this when instantiating a member `CXXRecordDecl` nested within a class template, and when instantiating a local class in a function template.
What should happen if more attributes are added between uses of the template? Example:
template<typename T> struct A;
template<typename T> struct [[deprecated]] A;
A<int> *q; // warn here?
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