adapt to change in Scala 2.13.9 + Scala 3.2.1

[SethTisue]

namely scala/scala#10047

this came up at scala/community-build#1579

not for merge until 2.13.9 is actually released and we can upgrade, so that compilation will succeed

in the meantime we can use the branch in the community build

[som-snytt]

I expected this to work:

➜  ~ skala -Xsource:3
Welcome to Scala 2.13.9-20220720-072233-0771b75 (OpenJDK 64-Bit Server VM, Java 18.0.1.1).
Type in expressions for evaluation. Or try :help.

scala> class C { def f(sb: StringBuilder): sb.type = sb }
class C

scala> class D extends C { override def f(sb: StringBuilder) = sb }
                                        ^
       error: incompatible type in overriding
       def f(sb: StringBuilder): sb.type (defined in class C);
        found   : (sb: StringBuilder): StringBuilder
        required: (sb: StringBuilder): sb.type

[SethTisue]

closing for now, but I've set a private reminder to reopen after 2.13.9 2.13.10 is out.

[SethTisue]

now there is a new problem: Scala 3 hasn't taken the 2.13.9 or 2.13.10 upgrades yet

until that's resolved, we'd need version-specific sources in order to cross-compile

I think it's fine to just wait until there's a Scala 3 version available that has taken the upgrade

[SethTisue]

2.13.10 upgrade PR is scala/scala3#16074 — I've been too busy with other things lately to attend to it, but it's near the top of my queue now

[SethTisue]

I think it's fine to just wait until there's a Scala 3 version available that has taken the upgrade

3.2.1-RC4 took the upgrade, so we should be able to move to 3.2.1 soon