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Selectable with `Fields` crashes with `invalid prefix ContextualMethodType` when `selectDynamic` has implicit context arguments #22023

Open soronpo opened 6 days ago

soronpo commented 6 days ago

Compiler version

v3.6.2-RC1

Minimized code

trait Ctx
class Foo extends Selectable:
  type Fields = (bar: Int, baz: Int)
  def selectDynamic(fieldName: String)(using Ctx): Any = ???

val f = Foo()
val bar = f.bar

Output (click arrow to expand)

```scala [error] java.lang.AssertionError: assertion failed: invalid prefix ContextualMethodType(List(x$2), List(TypeRef(ThisType(TypeRef(NoPrefix,module class )),trait Ctx)), TypeRef(TermRef(ThisType(TypeRef(NoPrefix,module class )),object scala),class Any)) [error] scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8) [error] dotty.tools.dotc.core.Types$NamedType.(Types.scala:2313) [error] dotty.tools.dotc.core.Types$TermRef.(Types.scala:2918) [error] dotty.tools.dotc.core.Types$CachedTermRef.(Types.scala:2999) [error] dotty.tools.dotc.core.Uniques$NamedTypeUniques.newType$1(Uniques.scala:44) [error] dotty.tools.dotc.core.Uniques$NamedTypeUniques.enterIfNew(Uniques.scala:46) [error] dotty.tools.dotc.core.Types$TermRef$.apply(Types.scala:3053) [error] dotty.tools.dotc.core.Types$TermRef$.apply(Types.scala:3059) [error] dotty.tools.dotc.ast.tpd$TreeOps$.select$extension(tpd.scala:941) [error] dotty.tools.dotc.ast.tpd$TreeOps$.cast$extension(tpd.scala:1039) [error] dotty.tools.dotc.ast.tpd$TreeOps$.cast$extension(tpd.scala:1034) [error] dotty.tools.dotc.ast.tpd$TreeOps$.ensureConforms$extension(tpd.scala:1048) [error] dotty.tools.dotc.typer.Typer.trySelectable$1(Typer.scala:876) [error] dotty.tools.dotc.typer.Typer.typedSelectWithAdapt(Typer.scala:906) [error] dotty.tools.dotc.typer.Typer.typeSelectOnTerm$1(Typer.scala:993) [error] dotty.tools.dotc.typer.Typer.typedSelect(Typer.scala:1031) [error] dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3468) [error] dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3577) [error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:3655) [error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:3659) [error] dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:3770) [error] dotty.tools.dotc.typer.Namer.typedAheadExpr$$anonfun$1(Namer.scala:1765) [error] dotty.tools.dotc.typer.Namer.typedAhead(Namer.scala:1755) [error] dotty.tools.dotc.typer.Namer.typedAheadExpr(Namer.scala:1765) [error] dotty.tools.dotc.typer.Namer.typedAheadRhs$1$$anonfun$1(Namer.scala:2123) [error] dotty.tools.dotc.inlines.PrepareInlineable$.dropInlineIfError(PrepareInlineable.scala:256) [error] dotty.tools.dotc.typer.Namer.typedAheadRhs$1(Namer.scala:2123) [error] dotty.tools.dotc.typer.Namer.rhsType$1(Namer.scala:2131) [error] dotty.tools.dotc.typer.Namer.cookedRhsType$1(Namer.scala:2150) [error] dotty.tools.dotc.typer.Namer.lhsType$1(Namer.scala:2151) [error] dotty.tools.dotc.typer.Namer.inferredResultType(Namer.scala:2162) [error] dotty.tools.dotc.typer.Namer.inferredType$1(Namer.scala:1808) [error] dotty.tools.dotc.typer.Namer.valOrDefDefSig(Namer.scala:1814) [error] dotty.tools.dotc.typer.Namer$Completer.typeSig(Namer.scala:823) [error] dotty.tools.dotc.typer.Namer$Completer.completeInCreationContext(Namer.scala:990) [error] dotty.tools.dotc.typer.Namer$Completer.complete(Namer.scala:859) [error] dotty.tools.dotc.core.SymDenotations$SymDenotation.completeFrom(SymDenotations.scala:175) [error] dotty.tools.dotc.core.Denotations$Denotation.completeInfo$1(Denotations.scala:190) [error] dotty.tools.dotc.core.Denotations$Denotation.info(Denotations.scala:192) [error] dotty.tools.dotc.core.SymDenotations$SymDenotation.ensureCompleted(SymDenotations.scala:393) [error] dotty.tools.dotc.typer.Typer.retrieveSym(Typer.scala:3440) [error] dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3465) [error] dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3577) [error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:3655) [error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:3659) [error] dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3681) [error] dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3727) [error] dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:3160) [error] dotty.tools.dotc.typer.Typer.typedTypeOrClassDef$1(Typer.scala:3481) [error] dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3485) [error] dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3577) [error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:3655) [error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:3659) [error] dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3681) [error] dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3727) [error] dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:3293) [error] dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3527) [error] dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3578) [error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:3655) [error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:3659) [error] dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:3770) [error] dotty.tools.dotc.typer.TyperPhase.typeCheck$$anonfun$1(TyperPhase.scala:47) [error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:15) [error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:10) [error] dotty.tools.dotc.core.Phases$Phase.monitor(Phases.scala:507) [error] dotty.tools.dotc.typer.TyperPhase.typeCheck(TyperPhase.scala:53) [error] dotty.tools.dotc.typer.TyperPhase.$anonfun$4(TyperPhase.scala:99) [error] scala.collection.Iterator$$anon$6.hasNext(Iterator.scala:479) [error] scala.collection.Iterator$$anon$9.hasNext(Iterator.scala:583) [error] scala.collection.immutable.List.prependedAll(List.scala:152) [error] scala.collection.immutable.List$.from(List.scala:685) [error] scala.collection.immutable.List$.from(List.scala:682) [error] scala.collection.IterableOps$WithFilter.map(Iterable.scala:900) [error] dotty.tools.dotc.typer.TyperPhase.runOn(TyperPhase.scala:98) [error] dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:343) [error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:15) [error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:10) [error] scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323) [error] dotty.tools.dotc.Run.runPhases$1(Run.scala:336) [error] dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:384) [error] dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:396) [error] dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:69) [error] dotty.tools.dotc.Run.compileUnits(Run.scala:396) [error] dotty.tools.dotc.Run.compileSources(Run.scala:282) [error] dotty.tools.dotc.Run.compile(Run.scala:267) [error] dotty.tools.dotc.Driver.doCompile(Driver.scala:37) [error] dotty.tools.xsbt.CompilerBridgeDriver.run(CompilerBridgeDriver.java:141) [error] dotty.tools.xsbt.CompilerBridge.run(CompilerBridge.java:22) [error] sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:91) [error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$7(MixedAnalyzingCompiler.scala:196) [error] scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23) [error] sbt.internal.inc.MixedAnalyzingCompiler.timed(MixedAnalyzingCompiler.scala:252) [error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4(MixedAnalyzingCompiler.scala:186) [error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4$adapted(MixedAnalyzingCompiler.scala:166) [error] sbt.internal.inc.JarUtils$.withPreviousJar(JarUtils.scala:241) [error] sbt.internal.inc.MixedAnalyzingCompiler.compileScala$1(MixedAnalyzingCompiler.scala:166) [error] sbt.internal.inc.MixedAnalyzingCompiler.compile(MixedAnalyzingCompiler.scala:214) [error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1(IncrementalCompilerImpl.scala:542) [error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1$adapted(IncrementalCompilerImpl.scala:542) [error] sbt.internal.inc.Incremental$.$anonfun$apply$3(Incremental.scala:178) [error] sbt.internal.inc.Incremental$.$anonfun$apply$3$adapted(Incremental.scala:176) [error] sbt.internal.inc.Incremental$$anon$2.run(Incremental.scala:454) [error] sbt.internal.inc.IncrementalCommon$CycleState.next(IncrementalCommon.scala:117) [error] sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:56) [error] sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:52) [error] sbt.internal.inc.IncrementalCommon.cycle(IncrementalCommon.scala:265) [error] sbt.internal.inc.Incremental$.$anonfun$incrementalCompile$8(Incremental.scala:409) [error] sbt.internal.inc.Incremental$.withClassfileManager(Incremental.scala:496) [error] sbt.internal.inc.Incremental$.incrementalCompile(Incremental.scala:396) [error] sbt.internal.inc.Incremental$.apply(Incremental.scala:204) [error] sbt.internal.inc.IncrementalCompilerImpl.compileInternal(IncrementalCompilerImpl.scala:542) [error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileIncrementally$1(IncrementalCompilerImpl.scala:496) [error] sbt.internal.inc.IncrementalCompilerImpl.handleCompilationError(IncrementalCompilerImpl.scala:332) [error] sbt.internal.inc.IncrementalCompilerImpl.compileIncrementally(IncrementalCompilerImpl.scala:433) [error] sbt.internal.inc.IncrementalCompilerImpl.compile(IncrementalCompilerImpl.scala:137) [error] sbt.Defaults$.compileIncrementalTaskImpl(Defaults.scala:2419) [error] sbt.Defaults$.$anonfun$compileIncrementalTask$2(Defaults.scala:2369) [error] sbt.internal.server.BspCompileTask$.$anonfun$compute$1(BspCompileTask.scala:41) [error] sbt.internal.io.Retry$.apply(Retry.scala:47) [error] sbt.internal.io.Retry$.apply(Retry.scala:29) [error] sbt.internal.io.Retry$.apply(Retry.scala:24) [error] sbt.internal.server.BspCompileTask$.compute(BspCompileTask.scala:41) [error] sbt.Defaults$.$anonfun$compileIncrementalTask$1(Defaults.scala:2367) [error] scala.Function1.$anonfun$compose$1(Function1.scala:49) [error] sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:63) [error] sbt.std.Transform$$anon$4.work(Transform.scala:69) [error] sbt.Execute.$anonfun$submit$2(Execute.scala:283) [error] sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:24) [error] sbt.Execute.work(Execute.scala:292) [error] sbt.Execute.$anonfun$submit$1(Execute.scala:283) [error] sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:265) [error] sbt.CompletionService$$anon$2.call(CompletionService.scala:65) [error] java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) [error] java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539) [error] java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) [error] java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) [error] java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) [error] java.base/java.lang.Thread.run(Thread.java:840) [error] [error] stack trace is suppressed; run last lib / Test / compileIncremental for the full output [error] (lib / Test / compileIncremental) java.lang.AssertionError: assertion failed: invalid prefix ContextualMethodType(List(x$2), List(TypeRef(ThisType(TypeRef(NoPrefix,module class )),trait Ctx)), TypeRef(TermRef(ThisType(TypeRef(NoPrefix,module class )),object scala),class Any)) ```
Gedochao commented 5 days ago

Note: this only started crashing since 3.5.0, although it has not been compiling for earlier versions.

scala-cli compile repro.scala -S 3.4.3

gives

[error] ./repro.scala:4:1
[error] '=>' expected, but 'end of statement' found
[error]   def selectDynamic(fieldName: String)(using Ctx): Any = ???
[error] ^^^
[error] ./repro.scala:7:11
[error] value bar is not a member of Foo
[error] val bar = f.bar
[error]           ^^^^^

So technically, the crash could be considered a regression.

Last good stable version: 3.4.3 First bad stable version: 3.5.0

soronpo commented 5 days ago

This is not a real regression because named tuple syntax did not exist until 3.5 (as experimental). So no bisect is needed. The implementation needs to be fixed to account for the implicit arguments in selectDynamic.

Gedochao commented 4 days ago

This is not a real regression because named tuple syntax did not exist until 3.5 (as experimental).

I know, but a compiler crash was still introduced. Grey zone, I know.