Internal error when compile generic case class with context function field

[romanowski]

Compiler version

3.0.0-M4-bin-20210207-16bf86f-NIGHTLY as well as 3.0.0-M3.

Minimized code

case class A[T](action: A[T] ?=> String) // produces error below

class A1[T](action: A1[T] ?=> String) // works
case class A2[T](action: A2[?] ?=> String) // works
case class A3[T](action: A3[T] => String) // works as well

Output

[info] exception occurred while typechecking /home/krzysiek/workspace/PG/derivation_bugs/src/main/scala/crash.scala
[info] exception occurred while compiling /home/krzysiek/workspace/PG/derivation_bugs/src/main/scala/crash.scala
java.lang.Error: internal error: type of right-hand side (A[<?>]) ?=> String is not fully defined, pos = <13..39> while compiling /home/krzysiek/workspace/PG/derivation_bugs/src/main/scala/crash.scala
[error] ## Exception when compiling 2 sources to /home/krzysiek/workspace/PG/derivation_bugs/target/scala-3.0.0-M4/classes
[error] java.lang.Error: internal error: type of right-hand side (A[<?>]) ?=> String is not fully defined, pos = <13..39>
[error] dotty.tools.dotc.typer.Inferencing$.fullyDefinedType(Inferencing.scala:54)
[error] dotty.tools.dotc.typer.Namer.lhsType$1(Namer.scala:1459)
[error] dotty.tools.dotc.typer.Namer.inferredType$1(Namer.scala:1470)
[error] dotty.tools.dotc.typer.Namer.valOrDefDefSig(Namer.scala:1479)
[error] dotty.tools.dotc.typer.Namer.defDefSig(Namer.scala:1562)
[error] dotty.tools.dotc.typer.Namer$Completer.typeSig(Namer.scala:703)
[error] dotty.tools.dotc.typer.Namer$Completer.completeInCreationContext(Namer.scala:830)
[error] dotty.tools.dotc.typer.Namer$Completer.complete(Namer.scala:731)
[error] dotty.tools.dotc.core.SymDenotations$SymDenotation.completeFrom(SymDenotations.scala:167)
[error] dotty.tools.dotc.core.Denotations$Denotation.completeInfo$1(Denotations.scala:188)
[error] dotty.tools.dotc.core.Denotations$Denotation.info(Denotations.scala:190)
[error] dotty.tools.dotc.core.SymDenotations$SymDenotation.ensureCompleted(SymDenotations.scala:369)
[error] dotty.tools.dotc.typer.Typer.retrieveSym(Typer.scala:2519)
[error] dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:2544)
[error] dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2638)
[error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:2704)
[error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:2708)
[error] dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:2730)
[error] dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:2780)
[error] dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:2227)
[error] dotty.tools.dotc.typer.Typer.typedTypeOrClassDef$2(Typer.scala:2565)
[error] dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:2569)
[error] dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2638)
[error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:2704)
[error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:2708)
[error] dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:2730)
[error] dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:2780)
[error] dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:2362)
[error] dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2610)
[error] dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2639)
[error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:2704)
[error] dotty.tools.dotc.typer.Typer.typed(Typer.scala:2708)
[error] dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:2824)
[error] dotty.tools.dotc.typer.FrontEnd.liftedTree1$1(FrontEnd.scala:79)
[error] dotty.tools.dotc.typer.FrontEnd.typeCheck$$anonfun$1(FrontEnd.scala:84)
[error] dotty.tools.dotc.typer.FrontEnd.monitor(FrontEnd.scala:43)
[error] dotty.tools.dotc.typer.FrontEnd.typeCheck(FrontEnd.scala:85)
[error] dotty.tools.dotc.typer.FrontEnd.runOn$$anonfun$3(FrontEnd.scala:120)
[error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
[error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
[error] scala.collection.immutable.List.foreach(List.scala:333)
[error] dotty.tools.dotc.typer.FrontEnd.runOn(FrontEnd.scala:120)
[error] dotty.tools.dotc.Run.runPhases$4$$anonfun$4(Run.scala:189)
[error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
[error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
[error] scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323)
[error] dotty.tools.dotc.Run.runPhases$5(Run.scala:199)
[error] dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:207)
[error] scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)
[error] dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:67)
[error] dotty.tools.dotc.Run.compileUnits(Run.scala:214)
[error] dotty.tools.dotc.Run.compileSources(Run.scala:150)
[error] dotty.tools.dotc.Run.compile(Run.scala:134)
[error] dotty.tools.dotc.Driver.doCompile(Driver.scala:39)
[error] dotty.tools.xsbt.CompilerBridgeDriver.run(CompilerBridgeDriver.java:88)
[error] dotty.tools.xsbt.CompilerBridge.run(CompilerBridge.java:22)
[error] sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:92)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$7(MixedAnalyzingCompiler.scala:186)
[error] scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
[error] sbt.internal.inc.MixedAnalyzingCompiler.timed(MixedAnalyzingCompiler.scala:241)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4(MixedAnalyzingCompiler.scala:176)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4$adapted(MixedAnalyzingCompiler.scala:157)
[error] sbt.internal.inc.JarUtils$.withPreviousJar(JarUtils.scala:239)
[error] sbt.internal.inc.MixedAnalyzingCompiler.compileScala$1(MixedAnalyzingCompiler.scala:157)
[error] sbt.internal.inc.MixedAnalyzingCompiler.compile(MixedAnalyzingCompiler.scala:204)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1(IncrementalCompilerImpl.scala:573)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1$adapted(IncrementalCompilerImpl.scala:573)
[error] sbt.internal.inc.Incremental$.$anonfun$apply$5(Incremental.scala:174)
[error] sbt.internal.inc.Incremental$.$anonfun$apply$5$adapted(Incremental.scala:172)
[error] sbt.internal.inc.Incremental$$anon$2.run(Incremental.scala:459)
[error] sbt.internal.inc.IncrementalCommon$CycleState.next(IncrementalCommon.scala:116)
[error] sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:56)
[error] sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:52)
[error] sbt.internal.inc.IncrementalCommon.cycle(IncrementalCommon.scala:261)
[error] sbt.internal.inc.Incremental$.$anonfun$incrementalCompile$8(Incremental.scala:414)
[error] sbt.internal.inc.Incremental$.withClassfileManager(Incremental.scala:499)
[error] sbt.internal.inc.Incremental$.incrementalCompile(Incremental.scala:401)
[error] sbt.internal.inc.Incremental$.apply(Incremental.scala:166)
[error] sbt.internal.inc.IncrementalCompilerImpl.compileInternal(IncrementalCompilerImpl.scala:573)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileIncrementally$1(IncrementalCompilerImpl.scala:491)
[error] sbt.internal.inc.IncrementalCompilerImpl.handleCompilationError(IncrementalCompilerImpl.scala:332)
[error] sbt.internal.inc.IncrementalCompilerImpl.compileIncrementally(IncrementalCompilerImpl.scala:420)
[error] sbt.internal.inc.IncrementalCompilerImpl.compile(IncrementalCompilerImpl.scala:137)
[error] sbt.Defaults$.compileIncrementalTaskImpl(Defaults.scala:2177)
[error] sbt.Defaults$.$anonfun$compileIncrementalTask$2(Defaults.scala:2134)
[error] sbt.internal.io.Retry$.apply(Retry.scala:40)
[error] sbt.internal.io.Retry$.apply(Retry.scala:23)
[error] sbt.internal.server.BspCompileTask$.compute(BspCompileTask.scala:31)
[error] sbt.Defaults$.$anonfun$compileIncrementalTask$1(Defaults.scala:2130)
[error] scala.Function1.$anonfun$compose$1(Function1.scala:49)
[error] sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:62)
[error] sbt.std.Transform$$anon$4.work(Transform.scala:68)
[error] sbt.Execute.$anonfun$submit$2(Execute.scala:282)
[error] sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:23)
[error] sbt.Execute.work(Execute.scala:291)
[error] sbt.Execute.$anonfun$submit$1(Execute.scala:282)
[error] sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:265)
[error] sbt.CompletionService$$anon$2.call(CompletionService.scala:64)
[error] java.util.concurrent.FutureTask.run(FutureTask.java:266)
[error] java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
[error] java.util.concurrent.FutureTask.run(FutureTask.java:266)
[error] java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
[error] java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
[error] java.lang.Thread.run(Thread.java:748)

Expectation

A successful compilation or meaningful compilation error.