Add optional seenfromClass to ThisTypeSubstitution

[dwijnand]

Pass in the context class of the member whose type is being substituted
(analagous to the seenFromClass passed to scalac's asSeenFrom). Use
this to guide the walk through enclosing classes.

Also, fix basetypes handling around ScThisType

Fixes SCL-21585
Fixes SCL-21947

[sugakandrey]

@dwijnand Thanks for the PR! I'll look into it in the next couple of days.

[dwijnand]

@sugakandrey any thoughts?

[sugakandrey]

@dwijnand I am sorry for the delay, I have not forgotten about this PR, despite how it might look. :)
I just had a quick look, seems very reasonable to me. I'll run your branch through our CI tomorrow and hopefully get it merged.

[lrytz]

For the record, I built the plugin with this change and tested it on scala/scala. It fixes the issue I reported (https://youtrack.jetbrains.com/issue/SCL-21947).

[sugakandrey]

@dwijnand
This is looking pretty good, only a couple of test failures, namely:

org.jetbrains.plugins.scala.projectHighlighting.scalaCompilerTestdata.ScalaCompilerTestdataHighlightingTest_2_12.testScalacTests
org.jetbrains.plugins.scala.lang.typeInference.generated.TypeInferencePatternTest.testDependent
org.jetbrains.plugins.scala.projectHighlighting.downloaded.MeerkatProjectHighlightingTest.testHighlighting
org.jetbrains.plugins.scala.lang.adjustTypes.tests.AdjustTypesTests.testRecursiveTypeAlias

I can try fixing them after I'm done with the stuff I'm working on right now or you can have a stab at it.

[dwijnand]

I can try fixing them after I'm done with the stuff I'm working on right now or you can have a stab at it.

I'm in a similar place. I'll ping when I reproduce those failures.

[dwijnand]

OK, I have the failures locally (can't remember if all of those failed) and I have a fix in the works.

[dwijnand]

@sugakandrey Could you give it another run? I found the fixes for testScalacTests, testDependent, and testRecursiveTypeAlias. But I minimised testHighlighting down to it passing and then back up to a minimised failure, and fix it, but hadn't realised that - for some reason - it doesn't pass locally for me even without my changes (I think!). So if you could rerun the tests, I can reassess from there.

[sugakandrey]

@dwijnand I'll give it a spin tomorrow.