Merge pull request #2965 from retronym/ticket/7859

SI-7859 Value classes may wrap a non-public member

2 files changed, 22 insertions, 11 deletions

diff --git a/src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala b/src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala
index f001964fb4..9e8cbe6c03 100644
--- a/src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala
+++ b/src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala
@@ -191,6 +191,9 @@ abstract class ExtensionMethods extends Transform with TypingTransformers {
             checkNonCyclic(currentOwner.pos, Set(), currentOwner) */
             extensionDefs(currentOwner.companionModule) = new mutable.ListBuffer[Tree]
             currentOwner.primaryConstructor.makeNotPrivate(NoSymbol)
+            // SI-7859 make param accessors accessible so the erasure can generate unbox operations.
+            val paramAccessors = currentOwner.info.decls.filter(sym => sym.isParamAccessor && sym.isMethod)
+            paramAccessors.foreach(_.makeNotPrivate(currentOwner))
             super.transform(tree)
           } else if (currentOwner.isStaticOwner) {
             super.transform(tree)
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index cb070a9843..ecd987b031 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -1356,17 +1356,25 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
         unit.error(clazz.pos, "value class may not be a "+
           (if (clazz.owner.isTerm) "local class" else "member of another class"))
       if (!clazz.isPrimitiveValueClass) {
-        clazz.info.decls.toList.filter(acc => acc.isMethod && acc.isParamAccessor) match {
-          case List(acc) =>
-            def isUnderlyingAcc(sym: Symbol) =
-              sym == acc || acc.hasAccessorFlag && sym == acc.accessed
-            if (acc.accessBoundary(clazz) != rootMirror.RootClass)
-              unit.error(acc.pos, "value class needs to have a publicly accessible val parameter")
-            else if (acc.tpe.typeSymbol.isDerivedValueClass)
-              unit.error(acc.pos, "value class may not wrap another user-defined value class")
-            checkEphemeral(clazz, body filterNot (stat => isUnderlyingAcc(stat.symbol)))
-          case x =>
-            unit.error(clazz.pos, "value class needs to have exactly one public val parameter")
+        clazz.primaryConstructor.paramss match {
+          case List(List(param)) =>
+            val decls = clazz.info.decls
+            val paramAccessor = clazz.constrParamAccessors.head
+            if (paramAccessor.isMutable)
+              unit.error(paramAccessor.pos, "value class parameter must not be a var")
+            val accessor = decls.toList.find(x => x.isMethod && x.accessedOrSelf == paramAccessor)
+            accessor match {
+              case None =>
+                unit.error(paramAccessor.pos, "value class parameter must be a val and not be private[this]")
+              case Some(acc) if acc.isProtectedLocal =>
+                unit.error(paramAccessor.pos, "value class parameter must not be protected[this]")
+              case Some(acc) =>
+                if (acc.tpe.typeSymbol.isDerivedValueClass)
+                  unit.error(acc.pos, "value class may not wrap another user-defined value class")
+                checkEphemeral(clazz, body filterNot (stat => stat.symbol != null && stat.symbol.accessedOrSelf == paramAccessor))
+            }
+          case _ =>
+            unit.error(clazz.pos, "value class needs to have exactly one val parameter")
         }
       }