Crash when instantiating path-dependent class from inlined method

[LPTK]

The following code crashes in the REPL:

sbt:dotty> repl
[warn] Multiple main classes detected.  Run show discoveredMainClasses to see the list
[info] Running (fork) dotty.tools.repl.Main -classpath .ivy2/cache/org.scala-lang/scala-library/jars/scala-library-2.12.8.jar:dotty/library/../out/bootstrap/dotty-library-bootstrapped/scala-0.14/dotty-library_0.14-0.14.0-bin-SNAPSHOT.jar

scala> class A { class AProxy }
// defined class A

scala> inline def head(a: A)(code: => a.AProxy): Unit = code
def head(a: A)(code: => a.AProxy): Unit

scala> head(new A)(new{})
Warning: mocking up superclass for module class <root>
java.lang.AssertionError: assertion failed: Cannot create ClassBType from NoSymbol
	at scala.Predef$.assert(Predef.scala:223)
	at dotty.tools.backend.jvm.BTypesFromSymbols.classBTypeFromSymbol(BTypesFromSymbols.scala:46)
	at dotty.tools.backend.jvm.BTypesFromSymbols.buildNestedInfo(BTypesFromSymbols.scala:154)
	at dotty.tools.backend.jvm.BTypesFromSymbols.setClassInfo(BTypesFromSymbols.scala:136)
	at dotty.tools.backend.jvm.BTypesFromSymbols.$anonfun$classBTypeFromSymbol$4(BTypesFromSymbols.scala:59)
	at scala.collection.MapLike.getOrElse(MapLike.scala:131)
	at scala.collection.MapLike.getOrElse$(MapLike.scala:129)
	at scala.collection.AbstractMap.getOrElse(Map.scala:63)
	at dotty.tools.backend.jvm.BTypesFromSymbols.classBTypeFromSymbol(BTypesFromSymbols.scala:53)
	at dotty.tools.backend.jvm.BCodeHelpers$BCInnerClassGen.getClassBTypeAndRegisterInnerClass(BCodeHelpers.scala:238)
	at dotty.tools.backend.jvm.BCodeHelpers$BCInnerClassGen.getClassBTypeAndRegisterInnerClass$(BCodeHelpers.scala:232)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.getClassBTypeAndRegisterInnerClass(BCodeSkelBuilder.scala:43)
	at dotty.tools.backend.jvm.DottyBackendInterface$$anon$9.$anonfun$toTypeKind$3(DottyBackendInterface.scala:906)
	at scala.collection.MapLike.getOrElse(MapLike.scala:131)
	at scala.collection.MapLike.getOrElse$(MapLike.scala:129)
	at scala.collection.AbstractMap.getOrElse(Map.scala:63)
	at dotty.tools.backend.jvm.DottyBackendInterface$$anon$9.primitiveOrClassToBType$1(DottyBackendInterface.scala:906)
	at dotty.tools.backend.jvm.DottyBackendInterface$$anon$9.toTypeKind(DottyBackendInterface.scala:925)
	at dotty.tools.backend.jvm.BCodeHelpers$BCInnerClassGen.toTypeKind(BCodeHelpers.scala:267)
	at dotty.tools.backend.jvm.BCodeHelpers$BCInnerClassGen.toTypeKind$(BCodeHelpers.scala:267)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.toTypeKind(BCodeSkelBuilder.scala:43)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.tpeTK(BCodeSkelBuilder.scala:75)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:263)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoadQualifier(BCodeBodyBuilder.scala:1009)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:378)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.$anonfun$genLoadArguments$1(BCodeBodyBuilder.scala:1051)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.$anonfun$genLoadArguments$1$adapted(BCodeBodyBuilder.scala:1051)
	at scala.collection.immutable.List.foreach(List.scala:392)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoadArguments(BCodeBodyBuilder.scala:1051)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genApply(BCodeBodyBuilder.scala:718)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:338)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genStat(BCodeBodyBuilder.scala:83)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.$anonfun$genBlock$1(BCodeBodyBuilder.scala:917)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.$anonfun$genBlock$1$adapted(BCodeBodyBuilder.scala:917)
	at scala.collection.immutable.List.foreach(List.scala:392)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genBlock(BCodeBodyBuilder.scala:917)
	at dotty.tools.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:409)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.emitNormalMethodBody$1(BCodeSkelBuilder.scala:597)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.genDefDef(BCodeSkelBuilder.scala:630)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.gen(BCodeSkelBuilder.scala:501)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.$anonfun$gen$1(BCodeSkelBuilder.scala:503)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.$anonfun$gen$1$adapted(BCodeSkelBuilder.scala:503)
	at scala.collection.immutable.List.foreach(List.scala:392)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.gen(BCodeSkelBuilder.scala:503)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.genPlainClass(BCodeSkelBuilder.scala:109)
	at dotty.tools.backend.jvm.GenBCodePipeline$Worker1.visit(GenBCode.scala:213)
	at dotty.tools.backend.jvm.GenBCodePipeline$Worker1.run(GenBCode.scala:180)
	at dotty.tools.backend.jvm.GenBCodePipeline.buildAndSendToDisk(GenBCode.scala:510)
	at dotty.tools.backend.jvm.GenBCodePipeline.run(GenBCode.scala:476)
	at dotty.tools.backend.jvm.GenBCode.run(GenBCode.scala:54)
	at dotty.tools.dotc.core.Phases$Phase.$anonfun$runOn$1(Phases.scala:309)
	at scala.collection.immutable.List.map(List.scala:286)
	at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:307)
	at dotty.tools.backend.jvm.GenBCode.runOn(GenBCode.scala:59)
	at dotty.tools.dotc.Run.$anonfun$compileUnits$3(Run.scala:158)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
	at dotty.tools.dotc.util.Stats$.trackTime(Stats.scala:49)
	at dotty.tools.dotc.Run.$anonfun$compileUnits$2(Run.scala:155)
	at dotty.tools.dotc.Run.$anonfun$compileUnits$2$adapted(Run.scala:153)
	at scala.collection.IndexedSeqOptimized.foreach(IndexedSeqOptimized.scala:36)
	at scala.collection.IndexedSeqOptimized.foreach$(IndexedSeqOptimized.scala:33)
	at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:198)
	at dotty.tools.dotc.Run.runPhases$1(Run.scala:153)
	at dotty.tools.dotc.Run.$anonfun$compileUnits$1(Run.scala:178)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
	at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:102)
	at dotty.tools.dotc.Run.compileUnits(Run.scala:133)
	at dotty.tools.dotc.Run.compileUnits(Run.scala:125)
	at dotty.tools.repl.ReplCompiler.runCompilationUnit(ReplCompiler.scala:152)
	at dotty.tools.repl.ReplCompiler.compile(ReplCompiler.scala:162)
	at dotty.tools.repl.ReplDriver.compile(ReplDriver.scala:216)
	at dotty.tools.repl.ReplDriver.interpret(ReplDriver.scala:182)
	at dotty.tools.repl.ReplDriver.loop$1(ReplDriver.scala:127)
	at dotty.tools.repl.ReplDriver.$anonfun$runUntilQuit$2(ReplDriver.scala:130)
	at scala.util.DynamicVariable.withValue(DynamicVariable.scala:62)
	at scala.Console$.withErr(Console.scala:196)
	at dotty.tools.repl.ReplDriver.$anonfun$withRedirectedOutput$1(ReplDriver.scala:143)
	at scala.util.DynamicVariable.withValue(DynamicVariable.scala:62)
	at scala.Console$.withOut(Console.scala:167)
	at dotty.tools.repl.ReplDriver.withRedirectedOutput(ReplDriver.scala:143)
	at dotty.tools.repl.ReplDriver.runUntilQuit(ReplDriver.scala:130)
	at dotty.tools.repl.Main$.main(Main.scala:6)
	at dotty.tools.repl.Main.main(Main.scala)
1 |head(new A)(new{})
  |                                                 ^^^^
  |A pure expression does nothing in statement position; you may be omitting necessary parentheses
Error while emitting rs$line$3
assertion failed: Cannot create ClassBType from NoSymbol

[allanrenucci]

This is not an issue with the REPL. The following code snippet crashes the compiler:

class A { class AProxy }

object B {
  inline def head(a: A)(code: => a.AProxy): Unit = code
  head(new A)(new{})
}