aaron.ballman added inline comments.
================
Comment at: clang/test/SemaCXX/using-if-exists.cpp:79
+ using B::mf UIE; // expected-note {{using declaration annotated with
'using_if_exists' here}}
+ using typename B::mt UIE; // expected-note 2 {{using declaration annotated
with 'using_if_exists' here}}
+
----------------
erik.pilkington wrote:
> Quuxplusone wrote:
> > I notice there's a hard `error: 'using_if_exists' attribute cannot be
> > applied to types` on
> >
> > using B::operator int UIE;
> >
> > Any thoughts on how to disambiguate that grammar?
> Hmm, that's an interesting case. I'm not sure what the right approach is. I
> think it would be a bit awkward to decide where to attach the attribute
> depending on what kind of entities the attribute could potentially apply to.
> FWIW this isn't a semantic restriction, since you can always just use the
> prefix syntax: `UIE using B::operator int;`. Maybe @aaron.ballman has some
> thoughts here?
By my reading of the standard, an attribute in that position really does apply
to the type `int` in that case.
https://eel.is/c++draft/namespace.udecl#nt:using-declarator
https://eel.is/c++draft/expr.prim.id.unqual#nt:unqualified-id
https://eel.is/c++draft/class.conv.fct#nt:conversion-function-id
https://eel.is/c++draft/class.conv.fct#nt:conversion-type-id
https://eel.is/c++draft/dcl.type.general#nt:type-specifier-seq
https://eel.is/c++draft/dcl.type.general#1.sentence-2
That said, I don't know if that's really *expected* behavior, so this might be
a question for WG21.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D90188/new/
https://reviews.llvm.org/D90188
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