[cxx-interop] Make sure we emit lifetime warnings for templated classes

[Xazax-hun]

rdar://155542619

[Xazax-hun]

@swift-ci please smoke test

[j-hui]

LGTM! But I only see changes to test cases. Was this working all along/fixed in a previous commit?

[j-hui]

Also: it might be too cumbersome for this patch, but I'm wondering whether we should convert this to a -verify test with expected errors instead of check statements.

[Xazax-hun]

Was this working all along/fixed in a previous commit?

It was always working, I think the example in the rdar is incomplete (some lifetimebound annotations missing). That was the reason why the warnings were not triggered there. But I figured we could add some tests to make sure this is covered.

[Xazax-hun]

wondering whether we should convert this to a -verify test with expected errors instead of check statements.

That would be great. Do you know if we have something akin to prefixes in FileCheck to make it easier to test multiple configs in the same file with -verify?