Opaque type's type parameter widened causing implicit lookup failure #12950
Description
Compiler version
3.0.0
Minimized code
package repro object repro: object opq: opaque type Lift[T] = Int extension(v: Int) def lift[T]: Lift[T] = v extension[T](l: Lift[T]) def value: Int = l export opq.Lift as Lift export opq.lift as lift final type Two extension[TL](l: Lift[TL]) def repro[TR](using m: Mul[TL, TR]): Int = l.value + m.value abstract class Mul[TL, TR]: val value: Int transparent inline given mulGivenInt[TL <: Int & Singleton, TR <: Int & Singleton]: Mul[TL, TR] = val m: Int = scala.compiletime.constValue[TL] * scala.compiletime.constValue[TR] new Mul[TL, TR] { val value: Int = m } transparent inline given mulGivenTwo[TR <: Int & Singleton]: Mul[Two, TR] = val m: Int = 2 * scala.compiletime.constValue[TR] new Mul[Two, TR] { val value: Int = m } Output
scala> import repro.repro.{*, given} // this works, using a type 'Two' that is not an integer literal scala> val x = 1.lift[Two] val x: repro.repro.opq.Lift[repro.repro.Two] = 1 scala> x.repro[2] val res0: Int = 5 // this will fail for some reason scala> val y = 1.lift[2] val y: repro.repro.opq.Lift[2] = 1 scala> y.repro[2] 1 |y.repro[2] | ^ |no implicit argument of type repro.repro.Mul[Int, (2 : Int)] was found for parameter m of method repro in object repro. |I found: | | repro.repro.mulGivenInt[(Int & Singleton), (Int & Singleton)] | |But given instance mulGivenInt in object repro does not match type repro.repro.Mul[Int, (2 : Int)]. Expectation
In the second example val y = 1.lift[2] I would expect that the integer literal type parameter not be widened to Int in the call to y.repro[2] - it should succeed and return 5, the same as with x.repro[2]
Instead the TL type parameter is being widened to Int: repro.repro.Mul[Int, (2 : Int)]
It seems to be specifically related to using opaque type - a more simple repro I attempted worked correctly, when the opaque type was not involved.