Add test cases for value class handling

compiler/src/dotty/tools/dotc/config/JavaPlatform.scala

@@ -53,7 +53,7 @@ class JavaPlatform extends Platform {
     // Superaccessors already show up as abstract methods here, so no test necessary
     cls.typeRef.fields.isEmpty &&
     // Check if the SAM can be implemented via LambdaMetaFactory
-    TypeErasure.samNotNeededExpansion(cls)
+    TypeErasure.samExpansionNotNeeded(cls)
 
   /** We could get away with excluding BoxedBooleanClass for the
    *  purpose of equality testing since it need not compare equal

compiler/src/dotty/tools/dotc/core/TypeErasure.scala

@@ -661,7 +661,7 @@ object TypeErasure:
    *  @param cls  The SAM class to check
    *  @return     true if LMF can handle the required adaptation
    */
-  def samNotNeededExpansion(cls: ClassSymbol)(using Context): Boolean = cls.typeRef.possibleSamMethods match
+  def samExpansionNotNeeded(cls: ClassSymbol)(using Context): Boolean = cls.typeRef.possibleSamMethods match
     case Seq(samMeth) =>
       val samMethSym = samMeth.symbol
       val erasedSamInfo = transformInfo(samMethSym, samMeth.info)
@@ -680,7 +680,7 @@ object TypeErasure:
           case _ => true
       }
     case _ => false
-  end samNotNeededExpansion
+  end samExpansionNotNeeded
 end TypeErasure
 
 import TypeErasure.*

tests/run/i24573.check

@@ -15,6 +15,7 @@
 22
 23
 24
+25
 31
 32
 33
@@ -35,6 +36,7 @@
 62
 63
 64
+65
 71
 72
 75

tests/run/i24573.scala

@@ -28,6 +28,9 @@ trait ConIS extends (Int => String):
 trait ConUU extends (() => Unit):
   def apply(): Unit
 
+trait ConVCVC extends (IntVal => IntVal):
+  def apply(t: IntVal): IntVal
+
 trait F1[-T, +R]:
   def apply(t: T): R
 
@@ -58,6 +61,9 @@ trait SFIS extends F1[Int, String]:
 trait SFIU extends F1[Int, Unit]:
   def apply(t: Int): Unit
 
+trait SFVCVC extends F1[IntVal, IntVal]:
+  def apply(t: IntVal): IntVal
+
 trait F1U[-T]:
   def apply(t: T): Unit
 
@@ -70,6 +76,8 @@ trait SF2I extends F1U[Int]:
 trait SF2S extends F1U[String]:
   def apply(t: String): Unit
 
+case class IntVal(value: Int) extends AnyVal
+
 object Test:
   def main(args: Array[String]): Unit =
     val fIU: (Int => Unit) = (x: Int) => println(x) // closure by JFunction1
@@ -112,6 +120,8 @@ object Test:
     println(conIS(23))
     val conUU: ConUU = () => println("24") // expanded
     conUU()
+    val conVCVC: ConVCVC = (x: IntVal) => IntVal(x.value + 1) // expanded
+    println(conVCVC(IntVal(24)).value)
 
     val ffIU: F1[Int, Unit] = (x: Int) => println(x) // closure
     ffIU(31)
@@ -159,6 +169,8 @@ object Test:
     println(sfIS(63))
     val sfIU: SFIU = (x: Int) => println(x) // expanded
     sfIU(64)
+    val sfVCVC: SFVCVC = (x: IntVal) => IntVal(x.value + 1) // expanded
+    println(sfVCVC(IntVal(64)).value)
 
     val f2ITU: F1U[Int] = (x: Int) => println(x) // closure
     f2ITU(71)