Nightly Dotty workflow of 2022-12-13 failed

[github-actions]

See https://github.com/lampepfl/dotty/actions/runs/3681874986

[nicolasstucki]

Something broke tests/pos-macros/i16420. I am bisecting it.

[nicolasstucki]

This tests was added as a regression test in 366b239

[dwijnand]

Ah, phew, was wondering why #16445 was failing with that and I couldn't reproduce locally..

[nicolasstucki]

It is a bug in #16345. I will fix it.