Failure in construction of path for outer accessor

[WojciechMazur]

Community build regression for https://github.com/disneystreaming/smithy4s (maintainer @Baccata)
Based on Open Community Build #2474
Part of #15647 regressions tracker

Compiler version

Works with 3.1.3
Fails with 3.2.0-RC1
Fails with 3.2.1-RC1-bin-20220711-6efd92d-NIGHTLY

Minimized code

trait Isomorphism[A, B] {
  def to(a: A): B
  def from(b: B): A
}

abstract class Newtype[A] {
 def apply(a: A): A = a

  implicit val isomorphismInstance: Isomorphism[A, A] =
    new Isomorphism[A, A] {
      inline def from(b: A): A = b
      inline def to(a: A): A = apply(a)
    }
}

Output (click arrow to expand)

[error] [core3] java.lang.AssertionError: assertion failed: failure to construct path from value Newtype_this/method from$retainedBody/anonymous class Object with 
[error] [core3]   smithy4s.capability.Isomorphism[A, Newtype.this.Type]
[error] [core3]  {...}/getter isomorphismInstance/class Newtype/package smithy4s/package <root> to `this` of  <none>;
[error] [core3] class Newtype in package smithy4s does not have an outer accessor
[error] [core3] scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
[error] [core3] dotty.tools.dotc.transform.ExplicitOuter$OuterOps$.loop$1(ExplicitOuter.scala:422)
[error] [core3] dotty.tools.dotc.transform.ExplicitOuter$OuterOps$.path$extension(ExplicitOuter.scala:441)
[error] [core3] dotty.tools.dotc.transform.ElimOuterSelect.transformSelect(ElimOuterSelect.scala:31)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.goSelect(MegaPhase.scala:605)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.goSelect(MegaPhase.scala:606)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.goSelect(MegaPhase.scala:606)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.goSelect(MegaPhase.scala:606)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.goSelect(MegaPhase.scala:606)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:228)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.mapValDef$1(MegaPhase.scala:234)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:239)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.recur$1(MegaPhase.scala:459)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:459)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformSpecificTrees(MegaPhase.scala:462)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:393)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.mapDefDef$1(MegaPhase.scala:248)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:251)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:438)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:438)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:359)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:255)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:444)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformBlock(MegaPhase.scala:449)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:298)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.mapValDef$1(MegaPhase.scala:234)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:239)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:438)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:438)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:359)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:255)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:438)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:438)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.mapPackage$1(MegaPhase.scala:379)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:382)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.transformUnit(MegaPhase.scala:454)
[error] [core3] dotty.tools.dotc.transform.MegaPhase.run(MegaPhase.scala:466)
[error] [core3] dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:311)
[error] [core3] scala.collection.immutable.List.map(List.scala:250)
[error] [core3] dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:312)
[error] [core3] dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:234)
[error] [core3] scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
[error] [core3] scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
[error] [core3] scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1328)
[error] [core3] dotty.tools.dotc.Run.runPhases$1(Run.scala:245)
[error] [core3] dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:253)
[error] [core3] dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:262)
[error] [core3] dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:68)
[error] [core3] dotty.tools.dotc.Run.compileUnits(Run.scala:262)
[error] [core3] dotty.tools.dotc.Run.compileSources(Run.scala:186)
[error] [core3] dotty.tools.dotc.Run.compile(Run.scala:170)
[error] [core3] dotty.tools.dotc.Driver.doCompile(Driver.scala:35)
[error] [core3] dotty.tools.xsbt.CompilerBridgeDriver.run(CompilerBridgeDriver.java:88)
[error] [core3] dotty.tools.xsbt.CompilerBridge.run(CompilerBridge.java:22)
[error] [core3] sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:91)
[error] [core3] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$7(MixedAnalyzingCompiler.scala:192)
[error] [core3] scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
[error] [core3] sbt.internal.inc.MixedAnalyzingCompiler.timed(MixedAnalyzingCompiler.scala:247)
[error] [core3] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4(MixedAnalyzingCompiler.scala:182)
[error] [core3] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4$adapted(MixedAnalyzingCompiler.scala:163)
[error] [core3] sbt.internal.inc.JarUtils$.withPreviousJar(JarUtils.scala:239)
[error] [core3] sbt.internal.inc.MixedAnalyzingCompiler.compileScala$1(MixedAnalyzingCompiler.scala:163)
[error] [core3] sbt.internal.inc.MixedAnalyzingCompiler.compile(MixedAnalyzingCompiler.scala:210)
[error] [core3] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1(IncrementalCompilerImpl.scala:528)
[error] [core3] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1$adapted(IncrementalCompilerImpl.scala:528)
[error] [core3] sbt.internal.inc.Incremental$.$anonfun$apply$5(Incremental.scala:177)
[error] [core3] sbt.internal.inc.Incremental$.$anonfun$apply$5$adapted(Incremental.scala:175)
[error] [core3] sbt.internal.inc.Incremental$$anon$2.run(Incremental.scala:461)
[error] [core3] sbt.internal.inc.IncrementalCommon$CycleState.next(IncrementalCommon.scala:116)
[error] [core3] sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:56)
[error] [core3] sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:52)
[error] [core3] sbt.internal.inc.IncrementalCommon.cycle(IncrementalCommon.scala:263)
[error] [core3] sbt.internal.inc.Incremental$.$anonfun$incrementalCompile$8(Incremental.scala:416)
[error] [core3] sbt.internal.inc.Incremental$.withClassfileManager(Incremental.scala:503)
[error] [core3] sbt.internal.inc.Incremental$.incrementalCompile(Incremental.scala:403)
[error] [core3] sbt.internal.inc.Incremental$.apply(Incremental.scala:169)
[error] [core3] sbt.internal.inc.IncrementalCompilerImpl.compileInternal(IncrementalCompilerImpl.scala:528)
[error] [core3] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileIncrementally$1(IncrementalCompilerImpl.scala:482)
[error] [core3] sbt.internal.inc.IncrementalCompilerImpl.handleCompilationError(IncrementalCompilerImpl.scala:332)
[error] [core3] sbt.internal.inc.IncrementalCompilerImpl.compileIncrementally(IncrementalCompilerImpl.scala:420)
[error] [core3] sbt.internal.inc.IncrementalCompilerImpl.compile(IncrementalCompilerImpl.scala:137)
[error] [core3] sbt.Defaults$.compileIncrementalTaskImpl(Defaults.scala:2366)
[error] [core3] sbt.Defaults$.$anonfun$compileIncrementalTask$2(Defaults.scala:2316)
[error] [core3] sbt.internal.server.BspCompileTask$.$anonfun$compute$1(BspCompileTask.scala:30)
[error] [core3] sbt.internal.io.Retry$.apply(Retry.scala:46)
[error] [core3] sbt.internal.io.Retry$.apply(Retry.scala:28)
[error] [core3] sbt.internal.io.Retry$.apply(Retry.scala:23)
[error] [core3] sbt.internal.server.BspCompileTask$.compute(BspCompileTask.scala:30)
[error] [core3] sbt.Defaults$.$anonfun$compileIncrementalTask$1(Defaults.scala:2314)
[error] [core3] scala.Function1.$anonfun$compose$1(Function1.scala:49)
[error] [core3] sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:62)
[error] [core3] sbt.std.Transform$$anon$4.work(Transform.scala:68)
[error] [core3] sbt.Execute.$anonfun$submit$2(Execute.scala:282)
[error] [core3] sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:23)
[error] [core3] sbt.Execute.work(Execute.scala:291)
[error] [core3] sbt.Execute.$anonfun$submit$1(Execute.scala:282)
[error] [core3] sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:265)
[error] [core3] sbt.CompletionService$$anon$2.call(CompletionService.scala:64)
[error] [core3] java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[error] [core3] java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
[error] [core3] java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[error] [core3] java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
[error] [core3] java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
[error] [core3] java.base/java.lang.Thread.run(Thread.java:834)
[error] [core3]            
[error] [core3] (core3 / Compile / compileIncremental) java.lang.AssertionError: assertion failed: failure to construct path from value Newtype_this/method from$retainedBody/anonymous class Object with 
[error] [core3]   smithy4s.capability.Isomorphism[A, Newtype.this.Type]
[error] [core3]  {...}/getter isomorphismInstance/class Newtype/package smithy4s/package <root> to `this` of  <none>;
[error] [core3] class Newtype in package smithy4s does not have an outer accessor

[KacperFKorban]

A bit simpler minimization:

trait GetInt {
  def value: Int // if we add inline here, the program compiles
}

class Newtype {
  def f: Int = ???

  val g = new GetInt {
    inline def value: Int = f // has to be inline to crash
  }
}

[odersky]

Can we get the commit that failed? There were two PRs that could have touched this.

[KacperFKorban]

Te first commit is 323dbce

[odersky]

In fact I wonder how this compiled at all before 323dbce. It seems that every call of the inline method would have caused an error then.

Ah, wait: It could be that only the implemented abstract method was a visible call target. But the the inline would in fact never be called.