fix memberType for constructor params

Author: zielinsky

compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala

@@ -1926,7 +1926,19 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
             else
               member.info
 
-          memberInfo.asSeenFrom(self, member.owner) match
+          val memberInfoSubstituted =
+            if member.owner.isConstructor then
+              self match
+                case dotc.core.Types.AppliedType(_, args) =>
+                  val ctorTypeParams = member.owner.paramSymss.flatten.filter(_.isType)
+                  if ctorTypeParams.length == args.length then
+                    memberInfo.subst(ctorTypeParams, args)
+                  else
+                    memberInfo
+                case _ => memberInfo
+            else memberInfo
+
+          memberInfoSubstituted.asSeenFrom(self, member.owner) match
             case dotc.core.Types.ClassInfo(prefix, sym, _, _, _) =>
               // We do not want to expose ClassInfo in the reflect API, instead we change it to a TypeRef,
               // see issue #22395

tests/pos-macros/i25565/Macro_1.scala

@@ -0,0 +1,70 @@
+import scala.quoted.*
+
+object Repro:
+  inline def singletonValues[A]: List[A] = ${ singletonValuesImpl[A] }
+
+  private def singletonValuesImpl[A: Type](using Quotes): Expr[List[A]] =
+    import quotes.reflect.*
+
+    def collectValues[T: Type]: List[Expr[T]] =
+      val tpe = TypeRepr.of[T]
+      tpe.dealias match
+        case o: OrType => unionValues[T](o)
+        case _ if tpe.isSingleton => singletonValue[T](tpe) :: Nil
+        case _ =>
+          val sym = tpe.typeSymbol
+          if sym.flags.is(Flags.Sealed) then sumValues[T](sym)
+          else if sym.flags.is(Flags.Case) && sym.caseFields.nonEmpty then productValues[T](tpe, sym)
+          else
+            report.errorAndAbort(
+              s"Cannot derive values for ${tpe.show}. Supported types: singleton types, " +
+                "enums, sealed traits/classes, union types, and case classes/tuples whose fields are all enumerable."
+            )
+
+    def singletonValue[T: Type](tpe: TypeRepr): Expr[T] =
+      tpe.asType match
+        case '[t] =>
+          Expr.summon[ValueOf[t]] match
+            case Some(vo) => '{ $vo.value }.asExprOf[T]
+            case None     => report.errorAndAbort(s"Cannot determine value for singleton type: ${tpe.show}")
+
+    def unionValues[T: Type](orType: OrType): List[Expr[T]] =
+      def extract(tpe: TypeRepr): List[Expr[T]] =
+        tpe.dealias match
+          case o: OrType          => extract(o.left) ++ extract(o.right)
+          case s if s.isSingleton => singletonValue[T](s) :: Nil
+          case other              => report.errorAndAbort(s"Unsupported type in union: ${other.show}.")
+      extract(orType)
+
+    def sumValues[T: Type](sym: Symbol): List[Expr[T]] =
+      sym.children.flatMap { child =>
+        if child.isTerm then
+          child.termRef.asType match
+            case '[t] =>
+              Expr.summon[ValueOf[t]] match
+                case Some(vo) => '{ $vo.value }.asExprOf[T] :: Nil
+                case None     => report.errorAndAbort(s"Cannot get value for: ${child.name}")
+        else
+          child.typeRef.asType match
+            case '[c] => collectValues[c].map(_.asExprOf[T])
+      }
+
+    def productValues[T: Type](tpe: TypeRepr, sym: Symbol): List[Expr[T]] =
+      val constructorParams = sym.primaryConstructor.paramSymss.flatten.filter(_.isTerm)
+      val fieldTypes = constructorParams.map(f => tpe.memberType(f).widen.dealias)
+      val fieldValueExprs: List[List[Term]] = fieldTypes.map { ft =>
+        ft.asType match
+          case '[f] => collectValues[f].map(_.asTerm)
+      }
+      val cartesian = fieldValueExprs.foldRight(List(List.empty[Term])) { (vals, acc) =>
+        for v <- vals; rest <- acc yield v :: rest
+      }
+      cartesian.map { args =>
+        val companion = Ref(sym.companionModule)
+        val applyMethod = sym.companionModule.methodMember("apply").head
+        val typeParams = applyMethod.paramSymss.flatten.filter(_.isTypeParam)
+        if typeParams.nonEmpty then Select.overloaded(companion, "apply", fieldTypes, args).asExprOf[T]
+        else Select.overloaded(companion, "apply", Nil, args).asExprOf[T]
+      }
+
+    Expr.ofList(collectValues[A])

tests/pos-macros/i25565/Test_2.scala

@@ -0,0 +1,27 @@
+object TestCase1:
+  enum Foo:
+    case A
+    case B
+  enum Bar:
+    case A
+    case B
+
+  val values = Repro.singletonValues[(Foo, Bar)]
+
+def TestCase2 =
+  type Foo = "a" | "b"
+  type Bar = "x" | "y"
+
+  val values = Repro.singletonValues[(Foo, Bar)]
+
+case class MyPair[A, B](first: A, second: B)
+
+object TestCase3:
+  enum X:
+    case P
+    case Q
+  enum Y:
+    case R
+    case S
+
+  val values = Repro.singletonValues[MyPair[X, Y]]