disable for scala2x generic product nonstatic

Author: bishabosha

community-build/community-projects/protoquill

@@ -850,7 +850,7 @@ object TypeOps:
   def stripTypeVars(tp: Type)(using Context): Type =
     new StripTypeVarsMap().apply(tp)
 
-  /** Converts the type into a form reachable from `declScope` with the given `prefix` */
+  /** Converts the type into a form reachable from with the given `prefix` */
   def healPrefix(tpe: Type, prefix: Type)(using Context): Either[String, Type] =
 
     final class HealPrefixUnwind(val error: String) extends scala.util.control.ControlThrowable

community-build/community-projects/scalatest

@@ -76,14 +76,16 @@ object SymUtils:
     *  Excluded are value classes, abstract classes and case classes with more than one
     *  parameter section.
     */
-    def whyNotGenericProduct(using Context): String =
+    def whyNotGenericProduct(pre: Type)(using Context): String =
       if (!self.is(CaseClass)) "it is not a case class"
       else if (self.is(Abstract)) "it is an abstract class"
       else if (self.primaryConstructor.info.paramInfoss.length != 1) "it takes more than one parameter list"
       else if (isDerivedValueClass(self)) "it is a value class"
+      else if (self.is(Scala2x) && !(pre == NoPrefix || pre.typeSymbol.isStaticOwner)) then
+        "it is not accessible in a static context"
       else ""
 
-    def isGenericProduct(using Context): Boolean = whyNotGenericProduct.isEmpty
+    def isGenericProduct(pre: Type)(using Context): Boolean = whyNotGenericProduct(pre: Type).isEmpty
 
     /** Is this an old style implicit conversion?
      *  @param directOnly            only consider explicitly written methods
@@ -134,7 +136,7 @@ object SymUtils:
     *     and also the location of the generated mirror.
     *   - all of its children are generic products, singletons, or generic sums themselves.
     */
-    def whyNotGenericSum(declScope: Symbol)(using Context): String =
+    def whyNotGenericSum(pre: Type, declScope: Symbol)(using Context): String =
       if (!self.is(Sealed))
         s"it is not a sealed ${self.kindString}"
       else if (!self.isOneOf(AbstractOrTrait))
@@ -155,10 +157,10 @@ object SymUtils:
           else if (!isAccessible(child.owner)) i"its child $child is not accessible"
           else if (!child.isClass) ""
           else {
-            val s = child.whyNotGenericProduct
+            val s = child.whyNotGenericProduct(pre)
             if (s.isEmpty) s
             else if (child.is(Sealed)) {
-              val s = child.whyNotGenericSum(if child.useCompanionAsSumMirror then child.linkedClass else ctx.owner)
+              val s = child.whyNotGenericSum(pre, if child.useCompanionAsSumMirror then child.linkedClass else ctx.owner)
               if (s.isEmpty) s
               else i"its child $child is not a generic sum because $s"
             } else i"its child $child is not a generic product because $s"
@@ -168,15 +170,8 @@ object SymUtils:
         else children.map(problem).find(!_.isEmpty).getOrElse("")
       }
 
-    def isGenericSum_(declScope: Symbol)(using Context): Either[String, Unit] =
-      val res = whyNotGenericSum(declScope)
-      if res.nonEmpty then
-        Left(res)
-      else
-        Right(())
-
-    def isGenericSum(declScope: Symbol)(using Context): Boolean =
-      isGenericSum_(declScope).isRight
+    def isGenericSum(pre: Type, declScope: Symbol)(using Context): Boolean =
+      whyNotGenericSum(pre, declScope).isEmpty
 
     /** If this is a constructor, its owner: otherwise this. */
     final def skipConstructor(using Context): Symbol =

community-build/community-projects/specs2

@@ -606,10 +606,10 @@ class SyntheticMembers(thisPhase: DenotTransformer) {
     if (clazz.is(Module)) {
       if (clazz.is(Case)) makeSingletonMirror()
       else if linked.exists then
-        if (linked.isGenericProduct) makeProductMirror(linked, pre, mirroredType)
-        else if (linked.isGenericSum(clazz)) makeSumMirror(linked, pre, mirroredType)
+        if (linked.isGenericProduct(pre)) makeProductMirror(linked, pre, mirroredType)
+        else if (linked.isGenericSum(pre, clazz)) makeSumMirror(linked, pre, mirroredType)
         else if (linked.is(Sealed))
-          derive.println(i"$linked is not a sum because ${linked.whyNotGenericSum(clazz)}")
+          derive.println(i"$linked is not a sum because ${linked.whyNotGenericSum(pre, clazz)}")
     }
     else if (impl.removeAttachment(ExtendsSingletonMirror).isDefined)
       makeSingletonMirror()

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

@@ -299,7 +299,7 @@ class Synthesizer(typer: Typer)(using @constructorOnly c: Context):
           else
             val mirrorType = mirrorCore(defn.Mirror_SingletonClass, mirroredType, mirroredType, module.name, formal)
             modulePath.cast(mirrorType)
-        else if mirroredType.classSymbol.isGenericProduct then
+        else if mirroredType.classSymbol.isGenericProduct(pre) then
           val cls = mirroredType.classSymbol
           val accessors = cls.caseAccessors.filterNot(_.isAllOf(PrivateLocal))
           val elemLabels = accessors.map(acc => ConstantType(Constant(acc.name.toString)))
@@ -342,8 +342,7 @@ class Synthesizer(typer: Typer)(using @constructorOnly c: Context):
       val pre = TypeOps.extractPrefix(mirroredType) match
         case Some(pre) => pre
         case _         => return EmptyTree
-      cls.isGenericSum_(if useCompanion then cls.linkedClass else ctx.owner) match
-      case Right(_) =>
+      if cls.isGenericSum(pre, if useCompanion then cls.linkedClass else ctx.owner) then
         val elemLabels = cls.children.map(c => ConstantType(Constant(c.name.toString)))
 
         def solveInner(sym: Symbol): Type = sym match
@@ -404,8 +403,7 @@ class Synthesizer(typer: Typer)(using @constructorOnly c: Context):
             if useCompanion then companionPath(mirroredType, span)
             else anonymousMirror(monoType, mirroredType, ExtendsSumMirror, Some(pre), span)
           mirrorRef.cast(mirrorType)
-      case Left(whyNot) =>
-        report.error(i"$cls is not a valid sum type because $whyNot", ctx.source.atSpan(span))
+      else
         EmptyTree
   end sumMirror
 
@@ -436,12 +434,15 @@ class Synthesizer(typer: Typer)(using @constructorOnly c: Context):
   val synthesizedMirror: SpecialHandler = (formal, span) =>
     formal.member(tpnme.MirroredType).info match
       case TypeBounds(mirroredType, _) =>
-        if mirroredType.termSymbol.is(CaseVal)
-           || mirroredType.classSymbol.isGenericProduct
-        then
-          synthesizedProductMirror(formal, span)
-        else
-          synthesizedSumMirror(formal, span)
+        TypeOps.extractPrefix(mirroredType) match
+          case Some(pre) =>
+            if mirroredType.termSymbol.is(CaseVal)
+               || mirroredType.classSymbol.isGenericProduct(pre)
+            then
+              synthesizedProductMirror(formal, span)
+            else
+              synthesizedSumMirror(formal, span)
+          case _ => EmptyTree
       case _ => EmptyTree
 
   private def escapeJavaArray(tp: Type)(using Context): Type = tp match

compiler/src/dotty/tools/dotc/transform/SymUtils.scala

@@ -0,0 +1,17 @@
+import collectionstrawman.*
+
+import scala.deriving.Mirror
+
+def syntheticSumMirror = {
+  val m = new ListModule()
+
+  val mIList = summon[Mirror.Of[m.IList[Int]]] // error: can't summon
+  type derivedICons = Tuple.Head[mIList.MirroredElemTypes]
+  val mICons = summon[Mirror.Of[derivedICons]] // error: can't summon
+}
+
+def syntheticProductMirror = {
+  val m = new ListModule()
+
+  val mIPair = summon[Mirror.Of[m.IPair[Int, String]]] // error: can't summon
+}

compiler/src/dotty/tools/dotc/transform/SyntheticMembers.scala

@@ -0,0 +1,13 @@
+val scala3Version = sys.props("plugin.scalaVersion")
+val scala2Version = sys.props("plugin.scala2Version")
+
+lazy val lib = project.in(file("lib"))
+  .settings(
+    scalaVersion := scala2Version
+  )
+
+lazy val app = project.in(file("app"))
+  .dependsOn(lib)
+  .settings(
+    scalaVersion := scala3Version
+  )

compiler/src/dotty/tools/dotc/typer/Synthesizer.scala

@@ -0,0 +1,13 @@
+package collectionstrawman
+
+class ListModule {
+
+  sealed trait IList[+A]
+  case class ICons[+A](head: A, next: IList[A]) extends IList[A]
+  case object INil extends IList[Nothing]
+
+  case class IPair[+A, +B](a: A, b: B)
+
+  case object IUnit
+
+}

sbt-test/scala2-compat/i13332-fail/app/App.scala

@@ -0,0 +1 @@
+-> app/compile

sbt-test/scala2-compat/i13332-fail/build.sbt

@@ -2,22 +2,34 @@ import collectionstrawman.*
 
 import scala.deriving.Mirror
 
-def syntheticSumMirror = {
-  val m = new ListModule()
-
-  val mIList = summon[Mirror.Of[m.IList[Int]]]
+def syntheticSumMirror_STATIC = {
+  val mIList = summon[Mirror.Of[ListStatic.IList[Int]]]
   type derivedICons = Tuple.Head[mIList.MirroredElemTypes]
   val mICons = summon[Mirror.Of[derivedICons]]
+  assert(mICons.fromProduct((1, ListStatic.INil)) == ListStatic.ICons(1, ListStatic.INil))
+  assert(mIList.ordinal(ListStatic.ICons(1, ListStatic.INil)) == 0)
+  assert(mIList.ordinal(ListStatic.INil) == 1)
 }
 
-def syntheticProductMirror = {
-  val m = new ListModule()
+def syntheticProductMirror_STATIC = {
+  val mIPair = summon[Mirror.Of[ListStatic.IPair[Int, String]]]
+  assert(mIPair.fromProduct((1, "foo")) == ListStatic.IPair(1, "foo"))
+}
 
-  val mIPair = summon[Mirror.Of[m.IPair[Int, String]]]
+def syntheticSingletonMirror_STATIC = {
+  val mIUnit = summon[Mirror.Of[ListStatic.IUnit.type]]
+  assert(mIUnit.fromProduct(EmptyTuple) eq ListStatic.IUnit)
 }
 
-def syntheticSingletonMirror = {
+def syntheticSingletonMirror_PATH_DEPENDENT = {
   val m = new ListModule()
 
   val mIUnit = summon[Mirror.Of[m.IUnit.type]]
+  assert(mIUnit.fromProduct(EmptyTuple) eq m.IUnit)
 }
+
+@main def Test =
+  syntheticSumMirror_STATIC
+  syntheticProductMirror_STATIC
+  syntheticSingletonMirror_STATIC
+  syntheticSingletonMirror_PATH_DEPENDENT

sbt-test/scala2-compat/i13332-fail/lib/Lib.scala

@@ -9,6 +9,5 @@ lazy val lib = project.in(file("lib"))
 lazy val app = project.in(file("app"))
   .dependsOn(lib)
   .settings(
-    scalaVersion := scala3Version,
-    scalacOptions += "-Ystop-after:inlining", // temporary until cause of large error is found
+    scalaVersion := scala3Version
   )

sbt-test/scala2-compat/i13332-fail/test

@@ -11,3 +11,15 @@ class ListModule {
   case object IUnit
 
 }
+
+object ListStatic {
+
+  sealed trait IList[+A]
+  case class ICons[+A](head: A, next: IList[A]) extends IList[A]
+  case object INil extends IList[Nothing]
+
+  case class IPair[+A, +B](a: A, b: B)
+
+  case object IUnit
+
+}

sbt-test/scala2-compat/i13332/app/App.scala

@@ -1,3 +1,2 @@
-# temporarily expect failure, actually this will pass, but we stop compilation early
-# with -Ystop-after:inlining to avoid a large error
--> app/compile
+> app/compile
+> app/run