Upgrade reference compiler to 3.0.1-RC2

[smarter]

No description provided.

[smarter]

 Error:  -- Error: /__w/dotty/dotty/library/src/scala/annotation/experimental.scala:14:6 
Error:  14 |class experimental extends StaticAnnotation
Error:     |^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error:     |use of @experimental is experimental and therefore may only be used with a nightly or snapshot version of the compiler

@nicolasstucki Did something change in how @experimental is checked between 3.0.0 and 3.0.1-RC2?

[bishabosha]

@nicolasstucki Did something change in how @experimental is checked between 3.0.0 and 3.0.1-RC2?

#12672?

[smarter]

@anatoliykmetyuk Should #12672 be backported to release-3.0.1? As is, the compiler from that branch cannot be used as a reference compiler, so we can't release 3.0.1 without fixing that.

[smarter]

Looks like the issue with @experimental doesn't happen when using a nightly as a reference compiler, so hopefully we'll be able to use 3.0.2-RC1 as our reference compiler (and just skip 3.0.1 since using the latest RC is more valuable anyway). However stdlib-sourcelinks-test fails currently:

Error: Test dotty.tools.scaladoc.sourcelinks.RemoteLinksTest.runTest failed: Page 3.0.2-RC1-bin-20210628-10145ff-NIGHTLY/tasty/src/dotty/tools/tasty/TastyBuffer.scala does not exists, took 4.883 sec

@BarkingBad could you have a look at why this test is failing when using a nightly compiler as our reference compiler?

[BarkingBad]

The RemoteLinksTest is supposed to test whether the source links are pointing to the correct repository and to the correct line. The source links of the new dotty classes are based on the referenceVersion property to build the link. It's not only the problem with the test, all the docs published after merging this PR will have source link url pointing to, for example: https://github.com/lampepfl/dotty/blob/3.0.2-RC1-bin-20210628-10145ff-NIGHTLY/library/src/scala/quoted/runtime/Expr.scala#L7, that will yield 404 (since the link is broken). We can either:

• provide git tag for the reference version (the links will work)
• remove referenceVersion property dependency from the calculated source-link and set it to be 3.0.0 for now (but we would have to update it after 3.0.1 release etc.
• all other solutions with conditional logic/dictionaries

What solution do you like the most?

[anatoliykmetyuk]

@anatoliykmetyuk Should #12672 be backported to release-3.0.1? As is, the compiler from that branch cannot be used as a reference compiler, so we can't release 3.0.1 without fixing that.

The functionality appears to already be present in 3.0.1 branch: https://github.com/lampepfl/dotty/blob/release-3.0.1/compiler/src/dotty/tools/dotc/config/Properties.scala#L91

[smarter]

@BarkingBad I'll let you choose what you think is best for maintaining this test, keeping in mind that we should really avoid having tests that can randomly start failing when something unrelated changes, so

remove referenceVersion property dependency from the calculated source-link and set it to be 3.0.0 for now (but we would have to update it after 3.0.1 release etc.

Seems fine to me.

[BarkingBad]

I checked it once again and missed Krzysztof has made some enhancement for links to point them to hash commit rather than to git tag, but didn't apply it for tasty sources (which defaulted to 3.0.0). I made PR to this branch that should fix that dotty-staging#18

[smarter]

Can you open a separate pr for that? We might not end up merging this one.

[BarkingBad]

Sure, here it is #12990

[odersky]

Fixed by changes to @experimental.