Specialization/constructors/genicode interaction

[scabug]

$ cat X.scala 
class Ctor[@specialized(Int) T](var t1: T, var t2: T) {

  // the block needs to be here to cause the crash:
  {
    // the code needs to be here to cause the crash:
    val XXX = "XXX"
    println(XXX)

    // boilerplate to force constructor specialization:
    t1 = t2
  }
}
$ scalac X.scala 
error: Unknown type: => String, => String [class scala.reflect.internal.Types$NullaryMethodType, class scala.reflect.internal.Types$NullaryMethodType] TypeRef? false
error: uncaught exception during compilation: scala.reflect.internal.FatalError
error: scala.reflect.internal.FatalError: 
     while compiling: X.scala
        during phase: icode
     library version: version 2.10.3-20130609-151224-a54d86b550
    compiler version: version 2.10.3-20130612-162255-3a959f7a05
  reconstructed args: 

  last tree to typer: Ident(t2$mcI$sp)
              symbol: value t2$mcI$sp (flags: <param> <triedcooking>)
   symbol definition: t2$mcI$sp: Int
                 tpe: Int
       symbol owners: value t2$mcI$sp -> constructor Ctor$mcI$sp -> class Ctor$mcI$sp -> package <empty>
      context owners: class Ctor$mcI$sp -> package <empty>

...

== Expanded type of tree ==

TypeRef(TypeSymbol(final abstract class Int extends ))

Unknown type: => String, => String [class scala.reflect.internal.Types$NullaryMethodType, class scala.reflect.internal.Types$NullaryMethodType] TypeRef? false
	at scala.reflect.internal.SymbolTable.abort(SymbolTable.scala:49)
	at scala.tools.nsc.Global.abort(Global.scala:254)
	at scala.tools.nsc.backend.icode.TypeKinds$class.toTypeKind(TypeKinds.scala:397)
	at scala.tools.nsc.backend.icode.ICodes.toTypeKind(ICodes.scala:20)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.genLoadSelect$1(GenICode.scala:1006)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.scala$tools$nsc$backend$icode$GenICode$ICodePhase$$genLoad(GenICode.scala:1022)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase$$anonfun$genLoadArguments$1.apply(GenICode.scala:1246)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase$$anonfun$genLoadArguments$1.apply(GenICode.scala:1244)
	at scala.collection.LinearSeqOptimized$class.foldLeft(LinearSeqOptimized.scala:111)
	at scala.collection.immutable.List.foldLeft(List.scala:84)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.genLoadArguments(GenICode.scala:1244)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.genLoadApply6$1(GenICode.scala:935)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.scala$tools$nsc$backend$icode$GenICode$ICodePhase$$genLoad(GenICode.scala:967)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.scala$tools$nsc$backend$icode$GenICode$ICodePhase$$genStat(GenICode.scala:187)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase$$anonfun$genStat$1.apply(GenICode.scala:156)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase$$anonfun$genStat$1.apply(GenICode.scala:156)
	at scala.collection.LinearSeqOptimized$class.foldLeft(LinearSeqOptimized.scala:111)
	at scala.collection.immutable.List.foldLeft(List.scala:84)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.genStat(GenICode.scala:156)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.scala$tools$nsc$backend$icode$GenICode$ICodePhase$$genLoad(GenICode.scala:1068)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.scala$tools$nsc$backend$icode$GenICode$ICodePhase$$genStat(GenICode.scala:187)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase$$anonfun$genStat$1.apply(GenICode.scala:156)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase$$anonfun$genStat$1.apply(GenICode.scala:156)
	at scala.collection.LinearSeqOptimized$class.foldLeft(LinearSeqOptimized.scala:111)
	at scala.collection.immutable.List.foldLeft(List.scala:84)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.genStat(GenICode.scala:156)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.scala$tools$nsc$backend$icode$GenICode$ICodePhase$$genLoad(GenICode.scala:1068)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.gen(GenICode.scala:124)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase$$anonfun$gen$1.apply(GenICode.scala:72)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase$$anonfun$gen$1.apply(GenICode.scala:72)
	at scala.collection.immutable.List.foreach(List.scala:318)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.gen(GenICode.scala:72)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.gen(GenICode.scala:149)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.gen(GenICode.scala:99)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase$$anonfun$gen$1.apply(GenICode.scala:72)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase$$anonfun$gen$1.apply(GenICode.scala:72)
	at scala.collection.immutable.List.foreach(List.scala:318)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.gen(GenICode.scala:72)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.gen(GenICode.scala:90)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.gen(GenICode.scala:68)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.apply(GenICode.scala:64)
	at scala.tools.nsc.Global$GlobalPhase.applyPhase(Global.scala:464)
	at scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:431)
	at scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:431)
	at scala.collection.Iterator$class.foreach(Iterator.scala:727)
	at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)
	at scala.tools.nsc.Global$GlobalPhase.run(Global.scala:431)
	at scala.tools.nsc.backend.icode.GenICode$ICodePhase.run(GenICode.scala:57)
	at scala.tools.nsc.Global$Run.compileUnitsInternal(Global.scala:1583)
	at scala.tools.nsc.Global$Run.compileUnits(Global.scala:1557)
	at scala.tools.nsc.Global$Run.compileSources(Global.scala:1553)
	at scala.tools.nsc.Global$Run.compile(Global.scala:1662)
	at scala.tools.nsc.Driver.doCompile(Driver.scala:33)
	at scala.tools.nsc.Main$.doCompile(Main.scala:79)
	at scala.tools.nsc.Driver.process(Driver.scala:54)
	at scala.tools.nsc.Driver.main(Driver.scala:67)
	at scala.tools.nsc.Main.main(Main.scala)

Note the constructor specialization happens in constructors and is key to the crash, thus the bug description mentions constructors.

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-7574?orig=1
Reporter: @VladUreche
Affected Versions: 2.10.2-RC2

[scabug]

@retronym said:
Another example from duplicate ticket: #8172

class Test5[@specialized(Float) T](val data : T) {
    data.asInstanceOf[Double] == 0.0f
}
Compiling this class fails:
class Test6[@specialized(Float) T](val data : T) {
    None match {
        case None => data.asInstanceOf[Double] == 0.0
    }
}

Unknown type: => None.type, => None.type [class scala.reflect.internal.Types$NullaryMethodType, class sca
la.reflect.internal.Types$NullaryMethodType] TypeRef? false
        at scala.reflect.internal.SymbolTable.abort(SymbolTable.scala:49)
        at scala.tools.nsc.Global.abort(Global.scala:254)
        at scala.tools.nsc.backend.icode.TypeKinds$class.toTypeKind(TypeKinds.scala:397)

[SethTisue]

closing backend tickets which are likely stale; comment and/or reopen if you have evidence this is still applicable

[retronym]

The error persists under the new backend:

class Test6[@specialized(Float) T](val data : T) {
    None match {
        case None => data.asInstanceOf[Double] == 0.0
    }
}

⚡ pbpaste > /tmp/test.scala; scalac /tmp/test.scala
warning: an unexpected type representation reached the compiler backend while compiling test.scala: => None.type. If possible, please file a bug on https://github.com/scala/bug/issues.
scala.MatchError: => None.type (of class scala.reflect.internal.Types$NullaryMethodType)
	at scala.tools.nsc.backend.jvm.BTypesFromSymbols.typeToBType(BTypesFromSymbols.scala:195)
	at scala.tools.nsc.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.symInfoTK(BCodeSkelBuilder.scala:78)