Overloading method with implicit methods.

[nicolasstucki]

This is not overloading issue, but I have no better word for it. If one defines two methods with the same arguments but one with implicit and the other one without, the compiler will crash.

class A {
  def foo(i: Int): Int = i
  def foo(implicit i: Int): Int = i
}

java.lang.AssertionError: assertion failed: data race? overwriting symbol of type ((i: Int)Int)(A.this.foo),
long form = TermRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,<empty>)),A)),foo)/withSig(Signature(List(scala.Int),scala.Int)) of class class dotty.tools.dotc.core.Types$TermRefWithSignature,
last sym id = 3803, new sym id = 3804,
last owner = class A, new owner = class A,
period = frontend at run 2
	at scala.Predef$.assert(Predef.scala:165)
	at dotty.tools.dotc.core.Types$NamedType.checkSymAssign(Types.scala:1506)
	at dotty.tools.dotc.core.Types$NamedType.setDenot(Types.scala:1541)
	at dotty.tools.dotc.core.Types$NamedType.withDenot(Types.scala:1534)
	at dotty.tools.dotc.core.Types$TermRef$.withSigAndDenot(Types.scala:1942)
	at dotty.tools.dotc.core.SymDenotations$SymDenotation.termRefWithSig(SymDenotations.scala:1105)
	at dotty.tools.dotc.typer.TypeAssigner$$anonfun$assignType$5.apply(TypeAssigner.scala:498)
	at dotty.tools.dotc.typer.TypeAssigner$$anonfun$assignType$5.apply(TypeAssigner.scala:498)
	at dotty.tools.dotc.core.Types$Type.orElse(Types.scala:99)
	at dotty.tools.dotc.typer.TypeAssigner$class.assignType(TypeAssigner.scala:498)
	at dotty.tools.dotc.typer.Typer.assignType(Typer.scala:64)
	at dotty.tools.dotc.typer.Typer$$anonfun$typedDefDef$1.apply(Typer.scala:1243)
	at dotty.tools.dotc.typer.Typer$$anonfun$typedDefDef$1.apply(Typer.scala:1214)
	at dotty.tools.dotc.util.Stats$.track(Stats.scala:35)
	at dotty.tools.dotc.typer.Typer.typedDefDef(Typer.scala:1214)
	at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:1505)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1562)
	at dotty.tools.dotc.typer.Typer$$anonfun$typed$2.apply(Typer.scala:1581)
	at dotty.tools.dotc.typer.Typer$$anonfun$typed$2.apply(Typer.scala:1579)
	at dotty.tools.dotc.reporting.Reporting$class.traceIndented(Reporter.scala:136)
	at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:57)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1579)
	at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:1603)
	at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:1623)
	at dotty.tools.dotc.typer.Typer$$anonfun$typedClassDef$1.apply(Typer.scala:1315)
	at dotty.tools.dotc.typer.Typer$$anonfun$typedClassDef$1.apply(Typer.scala:1261)
	at dotty.tools.dotc.util.Stats$.track(Stats.scala:35)
	at dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:1261)
	at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:1508)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1562)
	at dotty.tools.dotc.typer.Typer$$anonfun$typed$2.apply(Typer.scala:1581)
	at dotty.tools.dotc.typer.Typer$$anonfun$typed$2.apply(Typer.scala:1579)
	at dotty.tools.dotc.reporting.Reporting$class.traceIndented(Reporter.scala:136)
	at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:57)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1579)
	at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:1603)
	at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:1623)
	at dotty.tools.dotc.typer.Typer$$anonfun$typedPackageDef$1.apply(Typer.scala:1423)
	at dotty.tools.dotc.typer.Typer$$anonfun$typedPackageDef$1.apply(Typer.scala:1410)
	at dotty.tools.dotc.util.Stats$.track(Stats.scala:35)
	at dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:1410)
	at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:1547)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1563)
	at dotty.tools.dotc.typer.Typer$$anonfun$typed$2.apply(Typer.scala:1581)
	at dotty.tools.dotc.typer.Typer$$anonfun$typed$2.apply(Typer.scala:1579)
	at dotty.tools.dotc.reporting.Reporting$class.traceIndented(Reporter.scala:136)
	at dotty.tools.dotc.core.Contexts$Context.traceIndented(Contexts.scala:57)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1579)
	at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:1635)
	at dotty.tools.dotc.typer.FrontEnd$$anonfun$typeCheck$1.apply$mcV$sp(FrontEnd.scala:64)
	at dotty.tools.dotc.typer.FrontEnd.monitor(FrontEnd.scala:32)
	at dotty.tools.dotc.typer.FrontEnd.typeCheck(FrontEnd.scala:62)
	at dotty.tools.dotc.typer.FrontEnd$$anonfun$runOn$3.apply(FrontEnd.scala:93)
	at dotty.tools.dotc.typer.FrontEnd$$anonfun$runOn$3.apply(FrontEnd.scala:93)
	at scala.collection.immutable.List.foreach(List.scala:381)
	at dotty.tools.dotc.typer.FrontEnd.runOn(FrontEnd.scala:93)

[odersky]

That crash is only produced by -Yno-double-bindings, and it is inevitable. Without the option we get:

-- Error: i2002.scala ----------------------------------------------------------
3 |  def foo(implicit i: Int): Int = i
  |      ^
  |      method foo is already defined as method foo: (i: Int)Int
  |       (the definitions have matching type signatures)