"-language:experimental.packageObjectValues" compiler flag seems to be missing

[lihaoyi]

Compiler version

3.7.0-RC1

Minimized code

"-language:experimental.packageObjectValues"

Output

invalid choice(s) for -language:experimental.packageObjectValues```

Expectation

I would have expected this to work, since it's documented in #22011

[som-snytt]

The test has import language.experimental.packageObjectValues. @lihaoyi

That seems to be it.

[lihaoyi]

Thanks @som-snytt! is there any compiler flag I can use to turn it on project-wide?

[lihaoyi]

I thought -experimental would do it but it didn't seem to do anything

[lihaoyi]

"-language:experimental.packageObjectValues" doesn't seem to work either, says invalid choice(s) for -language:

[lihaoyi]

Maybe it needs to be added to this list?

scala3/compiler/src/dotty/tools/dotc/config/Feature.scala

Line 65 in 744ba92

)

[som-snytt]

Ha. I guess this message doesn't mean there is no compiler option.

    /** Experimental support for package object values
     */
    @compileTimeOnly("`packageObjectValues` can only be used at compile time in import statements")
    object packageObjectValues

You must be right.

The funny thing, Dr O complained once about keeping values in sync with options, and I contributed a terrible hack, perhaps my first contribution, that I'm pretty sure was not adopted.

Edit: it doesn't seem so hacky from this perspective.
#9915

[lihaoyi]

This kind of "collect a bunch of static definitions in a runtime data structure" is very common. In com-lihaoyi we do it in Mill, MainArgs, Scalatags (the CSS DSL), Cask, and other places. Not an uncommon problem at all. All of my libraries use macros for this

[lihaoyi]

Updated the issue title and description to refer to the CLI flag problem