`asTerm called on not-a-Term val <none>` thrown when compiling Dotty via Bloop

[mbovel]

I just cloned Dotty (at scala/scala3@c3d6c48) on a new Ubuntu machine and tried to use Bloop as the build server.

Metals seems to work: I can go to symbol, read doc, I have inlay type hints (😍), etc.

However, if I go to compiler/src/dotty/tools/dotc/typer/Typer.scala every time I save, even if I do no changes, scala3-compiler is recompiled entirely (~30 seconds approximately on this fast machine, would take 4 times more on my laptop):

2024.11.26 15:15:07 INFO  compiling scala3-compiler (582 scala sources and 8 java sources)
2024.11.26 15:15:38 WARN  javac exited with exit code 1
2024.11.26 15:15:38 INFO  time: compiled scala3-compiler in 32s
2024.11.26 15:15:47 INFO  compiling scala3-compiler (582 scala sources and 8 java sources)
2024.11.26 15:16:15 WARN  javac exited with exit code 1
2024.11.26 15:16:15 INFO  time: compiled scala3-compiler in 28s
2024.11.26 15:16:17 INFO  compiling scala3-compiler (582 scala sources and 8 java sources)
2024.11.26 15:16:45 WARN  javac exited with exit code 1
2024.11.26 15:16:45 INFO  time: compiled scala3-compiler in 28s
2024.11.26 15:31:49 INFO  compiling scala3-compiler (582 scala sources and 8 java sources)
2024.11.26 15:32:20 WARN  javac exited with exit code 1
2024.11.26 15:32:20 INFO  time: compiled scala3-compiler in 31s
2024.11.26 15:32:50 INFO  compiling scala3-compiler (582 scala sources and 8 java sources)
2024.11.26 15:33:21 WARN  javac exited with exit code 1

Looking further:

• There are errors reported in compiler/src/dotty/tools/dotc/sbt/interfaces/ProgressCallback.java and dotty/tools/dotc/sbt/interfaces/ProgressCallback.java:

  

• Compilation of scala3-compiler fails with a compiler crash: assertion failed: asTerm called on not-a-Term val <none>:

  scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
  dotty.tools.dotc.core.Symbols$Symbol.asTerm(Symbols.scala:186)
  dotty.tools.dotc.ast.tpd$.New(tpd.scala:544)
  dotty.tools.dotc.core.Annotations$Annotation$Child$.makeChildLater$1(Annotations.scala:233)
  dotty.tools.dotc.core.Annotations$Annotation$Child$.later$$anonfun$1(Annotations.scala:236)
  dotty.tools.dotc.core.Annotations$LazyAnnotation.tree(Annotations.scala:142)
  dotty.tools.dotc.core.Annotations$Annotation$Child$.unapply(Annotations.scala:244)
  dotty.tools.dotc.typer.Namer.insertInto$1(Namer.scala:489)
  dotty.tools.dotc.typer.Namer.addChild(Namer.scala:500)
  dotty.tools.dotc.typer.Namer$Completer.register$1(Namer.scala:967)
  dotty.tools.dotc.typer.Namer$Completer.registerIfChildInCreationContext$$anonfun$2(Namer.scala:979)
  scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
  scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
  scala.collection.immutable.List.foreach(List.scala:334)
  dotty.tools.dotc.typer.Namer$Completer.registerIfChildInCreationContext(Namer.scala:979)
  dotty.tools.dotc.typer.Namer$Completer.complete(Namer.scala:860)
  dotty.tools.dotc.core.SymDenotations$SymDenotation.completeFrom(SymDenotations.scala:175)
  dotty.tools.dotc.core.Denotations$Denotation.completeInfo$1(Denotations.scala:190)
  dotty.tools.dotc.core.Denotations$Denotation.info(Denotations.scala:192)
  dotty.tools.dotc.core.SymDenotations$SymDenotation.ensureCompleted(SymDenotations.scala:393)
  dotty.tools.dotc.typer.Typer.retrieveSym(Typer.scala:3426)
  dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3451)
  dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3563)
  dotty.tools.dotc.typer.Typer.typed(Typer.scala:3641)
  dotty.tools.dotc.typer.Typer.typed(Typer.scala:3645)
  dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3667)
  dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3713)
  dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:3161)
  dotty.tools.dotc.typer.Typer.typedTypeOrClassDef$1(Typer.scala:3467)
  dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3471)
  dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3563)
  dotty.tools.dotc.typer.Typer.typed(Typer.scala:3641)
  dotty.tools.dotc.typer.Typer.typed(Typer.scala:3645)
  dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3667)
  dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3713)
  dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:3161)
  dotty.tools.dotc.typer.Typer.typedTypeOrClassDef$1(Typer.scala:3467)
  dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3471)
  dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3563)
  dotty.tools.dotc.typer.Typer.typed(Typer.scala:3641)
  dotty.tools.dotc.typer.Typer.typed(Typer.scala:3645)
  dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3667)
  dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3713)
  dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:3294)
  dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3513)
  dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3564)
  dotty.tools.dotc.typer.Typer.typed(Typer.scala:3641)
  dotty.tools.dotc.typer.Typer.typed(Typer.scala:3645)
  dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3694)
  dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3713)
  dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:3294)
  dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3513)
  dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3564)
  dotty.tools.dotc.typer.Typer.typed(Typer.scala:3641)
  dotty.tools.dotc.typer.Typer.typed(Typer.scala:3645)
  dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3694)
  dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3713)
  dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:3294)
  dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3513)
  dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3564)
  dotty.tools.dotc.typer.Typer.typed(Typer.scala:3641)
  dotty.tools.dotc.typer.Typer.typed(Typer.scala:3645)
  dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:3756)
  dotty.tools.dotc.typer.TyperPhase.typeCheck$$anonfun$1(TyperPhase.scala:47)
  scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
  scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
  dotty.tools.dotc.core.Phases$Phase.monitor(Phases.scala:507)
  dotty.tools.dotc.typer.TyperPhase.typeCheck(TyperPhase.scala:53)
  dotty.tools.dotc.typer.TyperPhase.$anonfun$4(TyperPhase.scala:99)
  scala.collection.Iterator$$anon$6.hasNext(Iterator.scala:479)
  scala.collection.Iterator$$anon$9.hasNext(Iterator.scala:583)
  scala.collection.immutable.List.prependedAll(List.scala:152)
  scala.collection.immutable.List$.from(List.scala:685)
  scala.collection.immutable.List$.from(List.scala:682)
  scala.collection.IterableOps$WithFilter.map(Iterable.scala:900)
  dotty.tools.dotc.typer.TyperPhase.runOn(TyperPhase.scala:98)
  dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:343)
  scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
  scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
  scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323)
  dotty.tools.dotc.Run.runPhases$1(Run.scala:336)
  dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:384)
  dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:396)
  dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:69)
  dotty.tools.dotc.Run.compileUnits(Run.scala:396)
  dotty.tools.dotc.Run.compileSources(Run.scala:282)
  dotty.tools.dotc.interactive.InteractiveDriver.run(InteractiveDriver.scala:161)
  dotty.tools.pc.CachingDriver.run(CachingDriver.scala:45)
  dotty.tools.pc.PcInlayHintsProvider.<init>(PcInlayHintsProvider.scala:45)
  dotty.tools.pc.ScalaPresentationCompiler.inlayHints$$anonfun$1(ScalaPresentationCompiler.scala:122)
  

Debug files:

• metals.log
• reports.zip
• r_compiler-error_(scala3-compiler)_15-05-33-634.md

[mbovel]

If I disable inlay hints, I get the same error from a different place:

	dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:384)
	dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:396)
	dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:69)
	dotty.tools.dotc.Run.compileUnits(Run.scala:396)
	dotty.tools.dotc.Run.compileSources(Run.scala:282)
	dotty.tools.dotc.interactive.InteractiveDriver.run(InteractiveDriver.scala:161)
	dotty.tools.pc.CachingDriver.run(CachingDriver.scala:45)
	dotty.tools.pc.WithCompilationUnit.<init>(WithCompilationUnit.scala:31)
	dotty.tools.pc.SimpleCollector.<init>(PcCollector.scala:351)
	dotty.tools.pc.PcSemanticTokensProvider$Collector$.<init>(PcSemanticTokensProvider.scala:63)
	dotty.tools.pc.PcSemanticTokensProvider.Collector$lzyINIT1(PcSemanticTokensProvider.scala:63)
	dotty.tools.pc.PcSemanticTokensProvider.Collector(PcSemanticTokensProvider.scala:63)
	dotty.tools.pc.PcSemanticTokensProvider.provide(PcSemanticTokensProvider.scala:88)
	dotty.tools.pc.ScalaPresentationCompiler.semanticTokens$$anonfun$1(ScalaPresentationCompiler.scala:111)

r_compiler-error_(scala3-compiler)_15-52-50-375.md

[mbovel]

Well, I:

• ran rm -rf .bloop .bsp .metals **/target **/out out target,
• switched the pre-release version of Metals,

and now scala3-compiler is green and there are no more problems shown.

[tgodzik]

Could it be an issue with incremental compilation?