[libcxx-commits] [libcxx] [libcxx][ios] initialize __fill_val_ in _FillHelper (PR #110279)

[David Tenty via libcxx-commits]

daltenty wrote:

> How did you catch the bug? Is it possible to add a test that triggers that?

We have internal runs that test using the old headers with the new dylib (I guess it would be nice to have such runs for at least a few releases in the community CI ideally)

Adding a legitimate test against the current code doesn't seem straight forward, this depends on the old internal behaviour of `basic_ios<_CharT, _Traits>::fill()` in the header

https://github.com/llvm/llvm-project/pull/110279