Fix #8856: Keep transparent flag

[nicolasstucki]

No description provided.

[odersky]

I don't know. I mean, it would have been much easier to spend a flag for Transparent but I invested quite a bit of time to avoid it! We should try to reign in the number of flags, in particular the ones that are pickled in TastyFormat.

Would it be possible to detect transparency by looking at the RHS? if it's a Typed node with the type of the result type the function is transparent.

[nicolasstucki]

We cannot detect if a def is marked with transparent by looking it's RHS because it is ambiguous. Furthermore, we can't use that strategy to detect if a val was marked as transparent.

[nicolasstucki]

The alternative would be to add an annotation.

[odersky]

What is a transparent val?

[odersky]

I am beginning to think that the whole introduction of transparent was a mistake. Maybe we should have stuck with the special type syntax? The problem with modifiers is feature creep - they tend to go everywhere.

[nicolasstucki]

Still, we need a way for tools to know if an inline is transparent, regardless of the encoding.

[odersky]

Yes, but an inline could be declared transparent if its RHS is not a type ascription. The question is: can we always see that?