`MatchError` in presentation compiler on import and recompilations

[majk-p]

Error description

Presentation compiler error on freshly imported code, on re-imports and each file change. This can happen at random with 2.12.20 sources, when developing sbt plugin. The affected code is proprietary, the affected file is pretty long, but here's a similar code snippet. The offset in the exception points to the end of the last occurance of secrets: inherit.

private def deployAndTestWorkflowJob(
    envLower: String,
    runTests: Boolean
): String = {

  val deploy = s"""
     |  deploy-$envLower:
     |    needs: synthesize
     |    uses: some/reusable/workflow.yml@v1
     |    with:
     |      strategy: matrix
     |      stage: $envLower
     |      aws-regions: foo
     |      cdk-substage: app
     |      run-codedeploy: false
     |    secrets: inherit
     |""".stripMargin

  val test = s"""
     |  test-$envLower-with-infra:
     |    strategy:
     |      fail-fast: false
     |      matrix:
     |        regionConfigs: bar
     |    needs: [deploy-$envLower]
     |    uses: ./.github/workflows/run-tests.yml
     |    with:
     |      targetEnvironment: $envLower
     |      targetRegion: $${{ matrix.regionConfigs.targetRegion }}
     |      useGlobalEdge: $${{ matrix.regionConfigs.useGlobalEdge }}
     |    secrets: inherit
     |
     |  test-$envLower:
     |    strategy:
     |      fail-fast: false
     |      matrix:
     |        regionConfigs: bar
     |    uses: ./.github/workflows/run-tests.yml
     |    with:
     |      targetEnvironment: $envLower
     |      targetRegion: $${{ matrix.regionConfigs.targetRegion }}
     |      useGlobalEdge: $${{ matrix.regionConfigs.useGlobalEdge }}
     |    secrets: inherit
     |""".stripMargin

  if (runTests) deploy + test else deploy
}

Short summary:

scala.MatchError: (of class scala.reflect.internal.Types$ErrorType$)

Error stacktrace:

scala.reflect.internal.Definitions$DefinitionsClass.fixupAsAnyTrait(Definitions.scala:287)
	scala.reflect.internal.Definitions$DefinitionsClass.$anonfun$ComparableClass$1(Definitions.scala:411)
	scala.reflect.internal.Symbols$Symbol.modifyInfo(Symbols.scala:1572)
	scala.reflect.internal.Definitions$DefinitionsClass.ComparableClass$lzycompute(Definitions.scala:411)
	scala.reflect.internal.Definitions$DefinitionsClass.ComparableClass(Definitions.scala:411)
	scala.reflect.internal.Definitions$DefinitionsClass.hijackedCoreClasses$lzycompute(Definitions.scala:1449)
	scala.reflect.internal.Definitions$DefinitionsClass.hijackedCoreClasses(Definitions.scala:1448)
	scala.reflect.internal.Definitions$DefinitionsClass.symbolsNotPresentInBytecode$lzycompute(Definitions.scala:1457)
	scala.reflect.internal.Definitions$DefinitionsClass.symbolsNotPresentInBytecode(Definitions.scala:1457)
	scala.reflect.internal.Definitions$DefinitionsClass.init(Definitions.scala:1513)
	scala.tools.nsc.Global$Run.<init>(Global.scala:1225)
	scala.tools.nsc.interactive.Global$TyperRun.<init>(Global.scala:1323)
	scala.tools.nsc.interactive.Global.newTyperRun(Global.scala:1346)
	scala.tools.nsc.interactive.Global.<init>(Global.scala:294)
	scala.meta.internal.pc.MetalsGlobal.<init>(MetalsGlobal.scala:49)
	scala.meta.internal.pc.ScalaPresentationCompiler.newCompiler(ScalaPresentationCompiler.scala:627)
	scala.meta.internal.pc.ScalaPresentationCompiler.$anonfun$compilerAccess$1(ScalaPresentationCompiler.scala:147)
	scala.meta.internal.pc.CompilerAccess.loadCompiler(CompilerAccess.scala:40)
	scala.meta.internal.pc.CompilerAccess.retryWithCleanCompiler(CompilerAccess.scala:182)
	scala.meta.internal.pc.CompilerAccess.$anonfun$withSharedCompiler$1(CompilerAccess.scala:155)
	scala.Option.map(Option.scala:230)
	scala.meta.internal.pc.CompilerAccess.withSharedCompiler(CompilerAccess.scala:154)
	scala.meta.internal.pc.CompilerAccess.$anonfun$withInterruptableCompiler$1(CompilerAccess.scala:92)
	scala.meta.internal.pc.CompilerAccess.$anonfun$onCompilerJobQueue$1(CompilerAccess.scala:209)
	scala.meta.internal.pc.CompilerJobQueue$Job.run(CompilerJobQueue.scala:152)
	java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
	java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
	java.base/java.lang.Thread.run(Thread.java:1583)

Compiler options:

-deprecation -encoding UTF-8 -feature -unchecked -Ywarn-numeric-widen -Xlint:_,-unused -Ywarn-unused:_,-nowarn,-privates -Ywarn-dead-code -Ypartial-unification -Ybackend-parallelism 12 -language:_ -Xsource:3 -release 17 -target:jvm-1.8 -Wconf:cat=unused-nowarn:s -Xsource:3 -Xplugin:<HOME>/.cache/coursier/v1/https/repo1.maven.org/maven2/com/olegpy/better-monadic-for_2.12/0.3.1/better-monadic-for_2.12-0.3.1.jar -Xplugin:<HOME>/.cache/coursier/v1/https/repo1.maven.org/maven2/org/typelevel/kind-projector_2.12.20/0.13.3/kind-projector_2.12.20-0.13.3.jar -Yrangepos -Xplugin-require:semanticdb

Expected behaviour:

The file compiles, as it does in sbt.

Additionally, metals produces the error on each file edit, spamming with the same error reports.

Operating system:
Linux

Java version:
21.0.8

Editor/extension:
VSCodium v1.100.3

Metals version:
1.6.2

Extra context or search terms:

Workspace information:

• Scala versions: 2.12.20
• Build tools: sbt
• Build servers: Bloop v2.0.13
• All build tools in workspace: Bloop; sbt

[tgodzik]

Thanks for reporting, this looks unexpected. It seems requiredClass[java.lang.Comparable[_]] is failing to load the class, which should not happen at all. The info of that symbol is ErrorType and that later is not expected to happen.

Does it also happen with JDK 17? Does it happen with any other code or only in that repo? Does it happen if you remove any of the options?

[majk-p]

Does it happen with any other code or only in that repo?

Yes, the issue occurred in other files in that sbt module

Does it happen if you remove any of the options?

I tried filtering out some options, re-importing the project and it didn't help.

Does it also happen with JDK 17?

This got interesting - to test it I had to turn off vscodium (and metals). The issue was gone when I re-launched on 17, and still is gone when switched back to 21. Perhaps that was related to some internal state that got reset?

[tgodzik]

There might have been something wrong with the cached classes inside the compiler. I have seen that case happen and that was causing problems with 2.13, where internal caches got corrupted with time (caches used with -release flag). I clean them up manually in that case and it seems to have solved the problem. I haven't seen a similar issue in 2.12.x, but I might happen there.

We need to check if we have similar caches somewhere and handle it the same as with 2.13.