Intrinsify scala.compiletime.testing.typeChecks

[nicolasstucki]

As know from the start, this funtionallity should not have been added to the reflection API.
Nevertheless it is still possible to use its result in a macro.

[nicolasstucki]

@liufengyun could you help me to update the scalatest macros to use this new version? Have a look at how I handled it in tests/run-macros/reflect-typeChecks/assert_1.scala

[milessabin]

Is this going to break shapeless as well?

I'm happy to update as soon as there's a nightly build published with the change.

[bishabosha]

minitest also is affected
https://github.com/dotty-staging/minitest/blob/9d5fbb80dcb095baac88deb4960d616870745cf9/shared/src/main/scala/minitest/api/Asserts.scala#L129

[nicolasstucki]

Shapeless should not be affected. CI tests passed for it.

[nicolasstucki]

I will update minitest. With this change we will not need the macro anymore as it fixed #7040 and we can use that as implementation.

[liufengyun]

@nicolasstucki I'll have a look at ScalaTest.

[liufengyun]

@nicolasstucki This change makes it awkward to implement macros like assertDoesNotDompile in ScalaTest, as now it's impossible to call typeChecks from macro implementation --- the method has to be called inside the inline method.

On reflection, it seems compiletime + inline is not a good combination for the API, as one program's compile-time could be another program's run-time. The change makes it impossible to use the API from staging and macro implementation.

BTW, what makes it not fit in reflection API?

As know from the start, this funtionallity should not have been added to the reflection API.

[nicolasstucki]

It does not fit the TASTy reflection API because it has nothing to do with typed trees. We just added it there because it was a simple but dirty way to support it and unblock the scalatest/minitest macros.

[liufengyun]

This PR decides that typeChecks should only be used in inline methods instead of macros.

Approve based on the following reasons:

• the impact is limited AFAWK (some ScalaTest DSL has to be redesigned),
• it's always possible to restore the API when there is strong need.