Backport "Regression test for extension nullification, nowarn for different opacities" to 3.3 LTS#270

tgodzik merged 1 commit intolts-3.3scala/scala3-lts:lts-3.3from

backport-lts-3.3-21191scala/scala3-lts:backport-lts-3.3-21191Copy head branch name to clipboard