Should an 'extern(C++, "ns"):' override previous ones in the same scope?

[Jonathan M Davis]

On Sunday, September 8, 2019 12:12:53 PM MDT Exil via Digitalmars-d-learn 
wrote:
> On Saturday, 7 September 2019 at 22:19:48 UTC, Jonathan M Davis
>
> wrote:
> > On Saturday, September 7, 2019 3:40:58 PM MDT Exil via
> >
> > Digitalmars-d-learn wrote:
> >> On Saturday, 7 September 2019 at 17:22:07 UTC, Jonathan M Davis
> >>
> >> wrote:
> >> > @safe:
> >> > @system:
> >> >
> >> > then @system overrides @safe.
> >>
> >> Just to add onto this, you can't do:
> >>      @safe @system void foo(); // error
> >>
> >> but you can do:
> >>      extern(C++, ns1) extern(C++, ns2) void foo(); // ok
> >
> > It makes no sense to apply multiple namespaces to the same
> > symbol. I expect that this behavior is due to a lack of testing
> > (the same with the out of order weirdness in the other post).
> > It's the sort of thing that you test when you're trying to make
> > sure that the feature does the right thing when people use it
> > incorrectly, not the sort of thing when you're trying to make
> > sure that the feature works as intended, so it's easy to forget.
> >
> > My guess is that this behavior leaked its way in due to the
> > fact that you
> > need to be able to put multiple extern(C++) declarations on a
> > symbol when
> > you use extern(C++, struct) or extern(C++, class) in addition
> > to the
> > extern(C++) for the namespace.
> >
> > - Jonathan M Davis
>
> You don't need to make guesses or assumptions. It most definitely
> was intentional.
>
> https://github.com/dlang/dmd/commit/4b2578e208f2af9a02159fc2d8d87fb17b0900
> 5e#diff-62dcb5f0ffc3089b7565897d8beb3322R617
>
>
> By the looks of it, this feature was also implemented before
> extern(C++, struct/class).

Well, it's inconsistent with the rest of the language and bad design IMHO.
And even if it were desirable behavior, it clearly becomes a mess with the
ordering once the attributes are no longer directly on the symbol. Of
course, ideally, the whole extern(C++) feature with identifiers instead of
strings for the namespace would be deprecated anyway.

- Jonathan M Davis