Interaction between path-dependent types and default args fails to compile #23952
Description
Compiler version
3.7.0-3.7.3, 3.8.0-RC1-bin-20250819-1f13619-NIGHTLY
(Compiles on 3.6.4)
Minimized code
trait Typeclass[I] sealed trait Enumm { type Insider } object Enumm { case object Enumm1 extends Enumm { case class Insider() object Insider { given t: Typeclass[Insider] = new Typeclass[Insider] {} } } } class Foo implicit val f: Foo = new Foo def pathDependentTypeDefaultParam(tpe: Enumm)(i: tpe.Insider, p: Int = 0)(using t: Typeclass[tpe.Insider]): Int = p def defaultParamNotPDT(tpe: Enumm)(i: tpe.Insider, p: Int = 0)(using t:Foo): Int = p def pathDependentTypeDefaultParamOwnList(tpe: Enumm)(i: tpe.Insider)(p: Int = 0)(using t: Typeclass[tpe.Insider]): Int = p def main = { //doesn't compile //Error: No given instance of type Nothing & Typeclass[? <: Enumm.Enumm1#Insider] was found for parameter t of method foo pathDependentTypeDefaultParam(Enumm.Enumm1)(Enumm.Enumm1.Insider()) //compiles if default arg given explicitly pathDependentTypeDefaultParam(Enumm.Enumm1)(Enumm.Enumm1.Insider(), p = 0) //compiles if using non-path-dependent given defaultParamNotPDT(Enumm.Enumm1)(Enumm.Enumm1.Insider()) //with default args in own parameter list again doesn't compile //Error: No given instance of type Nothing & Typeclass[? <: Enumm.Enumm1#Insider] was found for parameter t of method foo3 pathDependentTypeDefaultParamOwnList(Enumm.Enumm1)(Enumm.Enumm1.Insider())() //again, compiles if default arg given explicitly pathDependentTypeDefaultParamOwnList(Enumm.Enumm1)(Enumm.Enumm1.Insider())(p = 0) } Output
[error] -- [E172] Type Error: /Users/jackwheatley/work/37test/src/main/scala/main.scala:29:69 [error] 29 | pathDependentTypeDefaultParam(Enumm.Enumm1)(Enumm.Enumm1.Insider()) [error] | ^ [error] |No given instance of type Nothing & Typeclass[? <: Enumm.Enumm1#Insider] was found for parameter t of method pathDependentTypeDefaultParam [error] -- [E172] Type Error: /Users/jackwheatley/work/37test/src/main/scala/main.scala:39:78 [error] 39 | pathDependentTypeDefaultParamOwnList(Enumm.Enumm1)(Enumm.Enumm1.Insider())() [error] | ^ [error] |No given instance of type Nothing & Typeclass[? <: Enumm.Enumm1#Insider] was found for parameter t of method pathDependentTypeDefaultParamOwnList [error] two errors found Expectation
The above code compiles in 3.6.4. Default arguments shouldn't affect implicit resolution.