odersky

Here's the note: ```scala /** The root import symbol hidden by this symbol, or NoSymbol if no such symbol is hidden. * Note: this computation needs to work even for...

Maybe there are other options like -YnoGenericSig that suppress some output in the generated files. Maybe these could be moved to -X since the goal is presumably to cut down...

We have to strike a balance but putting things under more locks is not the right way to proceed. `-Yexplicit-nulls` is a good example. If it was so well hidden...

> For experimental language features I think it's worthwhile having one mechanism. Generally I agree. There is a complication that the three experimental extension options we have, (explicit nulls and...

I am not sure it would be desirable. These are checking options that don't change the binary or tasty output in any way. So I don't see why they would...

@olhotak @liufengyun I think we can just make it a PR for -Ysafe-init.

About the -Yimport options. I think it's completely OK to compile with some customized root imports. But we should not express it using external options, but instead support it in...

This looks mostly good to me, except for - `-YcheckReentrant`: this is really intended only for bootstrapping the compiler itself. We are not prepared at the moment to make that...

That's a tricky one. Maybe we can add `updated` to `SeqViewOps` as an inline method? That should be backwards Tasty compatible.

This will clash with the proposed syntax changes for type classes, which would make the change unnecessary. I therefore like to put this on hold until the fate of these...