[PATCH] D120397: [C++20] [Modules] Make the linkage consistent for template and its specialization

[David Blaikie via Phabricator via cfe-commits]

dblaikie added inline comments.


================
Comment at: clang/test/Modules/inconsist-export-template.cpp:19-23
+// FIXME: We should reject following specialization,
+// since it tries to export a name which is already introduced.
+export template <>
+void f1<int>() {
+
----------------
urnathan wrote:
> ChuanqiXu wrote:
> > iains wrote:
> > > iains wrote:
> > > > ChuanqiXu wrote:
> > > > > urnathan wrote:
> > > > > > I don't think we should be testing for ill-formed code here.  We want to verify that explicit instantiations, explicit specializations and implicit instantiations all get the expected linkage -- both external linkage on exported entities, module linkage on non-exported module-purview entities.
> > > > > I think it could add an `expected-error` once we complete the check in compiler so I added the FIXME here.
> > > > would it be possible to find a suitable place in the source for the FIXME?
> > > > I would be concerned that it could get forgotten in the test-case.
> > > or maybe just file a PR for accepts invalid code?
> > I would like to send an issue after the patch to remind me not forgetting it. The issue is needed after the patch since it would crash too. I prefer to remain the FIXME here so that it would look like a pre-commit test case, which should be good.
> The way to not forget about this is to file a bug and assign it to yourself.  Not add a known-wrong testcase.
FWIW, I do sometimes put in known-bad test cases to document existing issues and also to make it easier to find existing test coverage/a good home for the test case (often I/we end up adding a new test file, because it's not obvious where related existing test coverage is).

If this is the right place for the future test case, and it documents a limitation with the existing behavior, I wouldn't be totally against including it here, with a FIXME and reference to a filed bug, ideally (though I think I've done this without a bug filed too).


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D120397/new/

https://reviews.llvm.org/D120397