Compiler accepts code that shouldn't typecheck, dies in the backend

[smarter]

I have no idea how this code manages to get past the frontend (this only happens in the REPL):

scala> class Foo(i: Int) 
// defined class Foo
scala> new Foo("42") 
java.lang.RuntimeException: Unexpected New(Foo/TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,module class <empty>)),rs$line$1$)),Foo)) reached GenBCode.
  Call was genLoad(New(TypeTree[TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,module class <empty>)),rs$line$1$)),Foo)]),Ljava/lang/Object;)
        at dotty.tools.backend.jvm.DottyBackendInterface.abort(DottyBackendInterface.scala:393)
        at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:313)
        at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.$anonfun$genLoadArguments$1(BCodeBodyBuilder.scala:1018)
        at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.$anonfun$genLoadArguments$1$adapted(BCodeBodyBuilder.scala:1018)
        at scala.collection.immutable.List.foreach(List.scala:389)
       ...

[allanrenucci]

This is not an issue with the REPL:

import dotty.Show._

class Foo(x: Int)

object Test {
  val res0 = new Foo("Hello")
}

Stacktrace

> dotc -d out tests/allan/Test.scala
[warn] Multiple main classes detected.  Run 'show discoveredMainClasses' to see the list
[warn] Multiple main classes detected.  Run 'show discoveredMainClasses' to see the list
[info] Packaging /Users/renucci/projects/dotty/compiler/target/scala-2.12/dotty-compiler_2.12-0.5.0-bin-SNAPSHOT-nonbootstrapped-tests.jar ...
[info] Packaging /Users/renucci/projects/dotty/compiler/target/scala-2.12/dotty-compiler_2.12-0.5.0-bin-SNAPSHOT-nonbootstrapped.jar ...
[info] Done packaging.
[info] Done packaging.
[info] Running dotty.tools.dotc.Main -classpath /Users/renucci/projects/dotty/library/target/scala-2.12/dotty-library_2.12-0.5.0-bin-SNAPSHOT-nonbootstrapped.jar -d out tests/allan/Test.scala
Unexpected New(Foo/TypeRef(ThisType(TypeRef(NoPrefix,module class )),Foo)) reached GenBCode.
  Call was genLoad(New(TypeTree[TypeRef(ThisType(TypeRef(NoPrefix,module class )),Foo)]),Ljava/lang/Object;)
java.lang.RuntimeException: Unexpected New(Foo/TypeRef(ThisType(TypeRef(NoPrefix,module class )),Foo)) reached GenBCode.
  Call was genLoad(New(TypeTree[TypeRef(ThisType(TypeRef(NoPrefix,module class )),Foo)]),Ljava/lang/Object;)
	at dotty.tools.backend.jvm.DottyBackendInterface.abort(DottyBackendInterface.scala:393)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:313)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.$anonfun$genLoadArguments$1(BCodeBodyBuilder.scala:1018)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.$anonfun$genLoadArguments$1$adapted(BCodeBodyBuilder.scala:1018)
	at scala.collection.immutable.List.foreach(List.scala:389)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoadArguments(BCodeBodyBuilder.scala:1018)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genNormalMethodCall$1(BCodeBodyBuilder.scala:725)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genApply(BCodeBodyBuilder.scala:754)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:337)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.$anonfun$genLoadArguments$1(BCodeBodyBuilder.scala:1018)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.$anonfun$genLoadArguments$1$adapted(BCodeBodyBuilder.scala:1018)
	at scala.collection.immutable.List.foreach(List.scala:389)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoadArguments(BCodeBodyBuilder.scala:1018)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genApply(BCodeBodyBuilder.scala:683)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:337)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:268)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoadQualifier(BCodeBodyBuilder.scala:976)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genNormalMethodCall$1(BCodeBodyBuilder.scala:722)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genApply(BCodeBodyBuilder.scala:754)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:337)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:268)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoadQualifier(BCodeBodyBuilder.scala:976)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genNormalMethodCall$1(BCodeBodyBuilder.scala:722)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genApply(BCodeBodyBuilder.scala:754)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:337)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genStat(BCodeBodyBuilder.scala:77)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.$anonfun$genBlock$1(BCodeBodyBuilder.scala:860)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.$anonfun$genBlock$1$adapted(BCodeBodyBuilder.scala:860)
	at scala.collection.immutable.List.foreach(List.scala:389)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genNormalBlock$1(BCodeBodyBuilder.scala:860)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genBlock(BCodeBodyBuilder.scala:892)
	at scala.tools.nsc.backend.jvm.BCodeBodyBuilder$PlainBodyBuilder.genLoad(BCodeBodyBuilder.scala:408)
	at scala.tools.nsc.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.emitNormalMethodBody$1(BCodeSkelBuilder.scala:602)
	at scala.tools.nsc.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.genDefDef(BCodeSkelBuilder.scala:635)
	at scala.tools.nsc.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.gen(BCodeSkelBuilder.scala:506)
	at scala.tools.nsc.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.$anonfun$gen$1(BCodeSkelBuilder.scala:508)
	at scala.tools.nsc.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.$anonfun$gen$1$adapted(BCodeSkelBuilder.scala:508)
	at scala.collection.immutable.List.foreach(List.scala:389)
	at scala.tools.nsc.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.gen(BCodeSkelBuilder.scala:508)
	at scala.tools.nsc.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.genPlainClass(BCodeSkelBuilder.scala:116)
	at dotty.tools.backend.jvm.GenBCodePipeline$Worker1.visit(GenBCode.scala:218)
	at dotty.tools.backend.jvm.GenBCodePipeline$Worker1.run(GenBCode.scala:171)
	at dotty.tools.backend.jvm.GenBCodePipeline.buildAndSendToDisk(GenBCode.scala:379)
	at dotty.tools.backend.jvm.GenBCodePipeline.run(GenBCode.scala:345)
	at dotty.tools.backend.jvm.GenBCode.run(GenBCode.scala:66)
	at dotty.tools.dotc.core.Phases$Phase.$anonfun$runOn$1(Phases.scala:289)
	at scala.collection.immutable.List.map(List.scala:283)
	at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:287)
	at dotty.tools.dotc.core.Phases$Phase.runOn$(Phases.scala:286)
	at dotty.tools.backend.jvm.GenBCode.runOn(GenBCode.scala:71)
	at dotty.tools.dotc.Run.$anonfun$compileUnits$3(Run.scala:125)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
	at dotty.tools.dotc.util.Stats$.trackTime(Stats.scala:47)
	at dotty.tools.dotc.Run.$anonfun$compileUnits$2(Run.scala:123)
	at dotty.tools.dotc.Run.$anonfun$compileUnits$2$adapted(Run.scala:121)
	at scala.collection.IndexedSeqOptimized.foreach(IndexedSeqOptimized.scala:32)
	at scala.collection.IndexedSeqOptimized.foreach$(IndexedSeqOptimized.scala:29)
	at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:191)
	at dotty.tools.dotc.Run.runPhases$1(Run.scala:121)
	at dotty.tools.dotc.Run.$anonfun$compileUnits$1(Run.scala:141)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
	at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:86)
	at dotty.tools.dotc.Run.compileUnits(Run.scala:107)
	at dotty.tools.dotc.Run.compileSources(Run.scala:94)
	at dotty.tools.dotc.Run.compile(Run.scala:78)
	at dotty.tools.dotc.Driver.doCompile(Driver.scala:29)
	at dotty.tools.dotc.Driver.process(Driver.scala:127)
	at dotty.tools.dotc.Driver.process(Driver.scala:96)
	at dotty.tools.dotc.Driver.process(Driver.scala:108)
	at dotty.tools.dotc.Driver.main(Driver.scala:135)
	at dotty.tools.dotc.Main.main(Main.scala)
Error while emitting Test.scala
Unexpected New(Foo/TypeRef(ThisType(TypeRef(NoPrefix,module class )),Foo)) reached GenBCode.
  Call was genLoad(New(TypeTree[TypeRef(ThisType(TypeRef(NoPrefix,module class )),Foo)]),Ljava/lang/Object;)
 

[allanrenucci]

The compiler shouldn't try this hard to make it compile:

val res0: dotty.Show.ShowValue[Object] = 
   dotty.Show.ShowValue[Object](new Foo)[Object]("Hello")