Merge pull request #2965 from retronym/ticket/7859

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

10 files changed, 147 insertions, 37 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")
         }
       }
 
diff --git a/test/files/neg/anyval-anyref-parent.check b/test/files/neg/anyval-anyref-parent.check
index 8c2aa36583..8a00fb394d 100644
--- a/test/files/neg/anyval-anyref-parent.check
+++ b/test/files/neg/anyval-anyref-parent.check
@@ -4,9 +4,9 @@ trait Foo2 extends AnyVal // fail
 anyval-anyref-parent.scala:5: error: Any does not have a constructor
 class Bar1 extends Any      // fail
                    ^
-anyval-anyref-parent.scala:6: error: value class needs to have exactly one public val parameter
+anyval-anyref-parent.scala:6: error: value class parameter must be a val and not be private[this]
 class Bar2(x: Int) extends AnyVal // fail
-      ^
+           ^
 anyval-anyref-parent.scala:10: error: illegal inheritance; superclass Any
  is not a subclass of the superclass Object
  of the mixin trait Immutable
diff --git a/test/files/neg/t7859.check b/test/files/neg/t7859.check
new file mode 100644
index 0000000000..5789e2a122
--- /dev/null
+++ b/test/files/neg/t7859.check
@@ -0,0 +1,19 @@
+B_2.scala:6: error: not found: value x
+  new p1.A(x).x
+           ^
+B_2.scala:6: error: value x in class A cannot be accessed in p1.A
+  new p1.A(x).x
+              ^
+B_2.scala:7: error: not found: value x
+  new B(x).x
+        ^
+B_2.scala:7: error: value x is not a member of B
+  new B(x).x
+           ^
+B_2.scala:8: error: not found: value x
+  new C(x).x
+        ^
+B_2.scala:8: error: value x in class C cannot be accessed in C
+  new C(x).x
+           ^
+6 errors found
diff --git a/test/files/neg/t7859/A_1.scala b/test/files/neg/t7859/A_1.scala
new file mode 100644
index 0000000000..e5b32d1c96
--- /dev/null
+++ b/test/files/neg/t7859/A_1.scala
@@ -0,0 +1,5 @@
+package p1 {
+  class A(private[p1] val x: Any) extends AnyVal
+}
+class B(private val x: Any) extends AnyVal
+
diff --git a/test/files/neg/t7859/B_2.scala b/test/files/neg/t7859/B_2.scala
new file mode 100644
index 0000000000..2e0556bc7b
--- /dev/null
+++ b/test/files/neg/t7859/B_2.scala
@@ -0,0 +1,9 @@
+class C(private val x: Any) extends AnyVal
+
+// Checking that makeNotPrivate(paramAccessor) doesn't make this visible during typer.
+// The output is identical with/without `extends AnyVal`.
+object Test {
+  new p1.A(x).x
+  new B(x).x
+  new C(x).x
+}
diff --git a/test/files/neg/valueclasses.check b/test/files/neg/valueclasses.check
index 3b82a8358c..35d38aae60 100644
--- a/test/files/neg/valueclasses.check
+++ b/test/files/neg/valueclasses.check
@@ -4,40 +4,43 @@ trait T extends AnyVal // fail
 valueclasses.scala:6: error: value class may not be a member of another class
   class Bar(x: Int) extends AnyVal // fail
         ^
+valueclasses.scala:6: error: value class parameter must be a val and not be private[this]
+  class Bar(x: Int) extends AnyVal // fail
+            ^
 valueclasses.scala:8: error: value class may not be a local class
     class Baz(x: Int) extends AnyVal // fail
           ^
-valueclasses.scala:12: error: value class needs to have exactly one public val parameter
+valueclasses.scala:8: error: value class parameter must be a val and not be private[this]
+    class Baz(x: Int) extends AnyVal // fail
+              ^
+valueclasses.scala:12: error: value class needs to have exactly one val parameter
 class V1 extends AnyVal // fail
       ^
-valueclasses.scala:14: error: value class needs to have a publicly accessible val parameter
-class V2(private[test] val x: Int) extends AnyVal // fail
-                           ^
-valueclasses.scala:15: error: value class needs to have a publicly accessible val parameter
-class V3(protected[test] val x: Int) extends AnyVal // fail
-                             ^
-valueclasses.scala:16: error: value class needs to have a publicly accessible val parameter
-class V4(protected val x: Int) extends AnyVal // fail
-                       ^
-valueclasses.scala:17: error: value class needs to have a publicly accessible val parameter
-class V5(private val x: Int) extends AnyVal // fail
-                     ^
-valueclasses.scala:19: error: value class needs to have exactly one public val parameter
+valueclasses.scala:19: error: value class needs to have exactly one val parameter
 class V6(val x: Int, val y: String) extends AnyVal // fail
       ^
-valueclasses.scala:20: error: field definition is not allowed in value class
+valueclasses.scala:20: error: value class needs to have exactly one val parameter
 class V7(val x: Int, private[this] val y: String) extends AnyVal // fail
-                                       ^
-valueclasses.scala:21: error: value class needs to have exactly one public val parameter
-class V8(var x: Int) extends AnyVal // fail
       ^
+valueclasses.scala:21: error: value class parameter must not be a var
+class V8(var x: Int) extends AnyVal // fail
+             ^
 valueclasses.scala:24: error: field definition is not allowed in value class
   val y = x    // fail
       ^
 valueclasses.scala:29: error: type parameter of value class may not be specialized
 class V12[@specialized T, U](val x: (T, U)) extends AnyVal // fail
                        ^
-valueclasses.scala:31: error: value class needs to have exactly one public val parameter
+valueclasses.scala:31: error: value class parameter must be a val and not be private[this]
 class V13(x: Int) extends AnyVal // fail
+          ^
+valueclasses.scala:33: error: value class parameter must be a val and not be private[this]
+class V14(private[this] val x: Int) extends AnyVal // fail
+                            ^
+valueclasses.scala:34: error: value class parameter must not be protected[this]
+class V15(protected[this] val x: Int) extends AnyVal // fail
+                              ^
+valueclasses.scala:36: error: value class needs to have exactly one val parameter
+class V16()(val a: Any) extends AnyVal // fail, was allowed 2.10.x
       ^
-14 errors found
+15 errors found
diff --git a/test/files/neg/valueclasses.scala b/test/files/neg/valueclasses.scala
index 7cac94ab11..06fde40a70 100644
--- a/test/files/neg/valueclasses.scala
+++ b/test/files/neg/valueclasses.scala
@@ -11,10 +11,10 @@ class Foo {
 
 class V1 extends AnyVal // fail
 
-class V2(private[test] val x: Int) extends AnyVal // fail
-class V3(protected[test] val x: Int) extends AnyVal // fail
-class V4(protected val x: Int) extends AnyVal // fail
-class V5(private val x: Int) extends AnyVal // fail
+class V2(private[test] val x: Int) extends AnyVal // okay, wasn't allowed in 2.10.x
+class V3(protected[test] val x: Int) extends AnyVal // okay, wasn't allowed in 2.10.x
+class V4(protected val x: Int) extends AnyVal // okay, wasn't allowed in 2.10.x
+class V5(private val x: Int) extends AnyVal // okay, wasn't allowed in 2.10.x
 
 class V6(val x: Int, val y: String) extends AnyVal // fail
 class V7(val x: Int, private[this] val y: String) extends AnyVal // fail
@@ -29,3 +29,8 @@ class V11[T](val x: List[T]) extends AnyVal // ok
 class V12[@specialized T, U](val x: (T, U)) extends AnyVal // fail
 
 class V13(x: Int) extends AnyVal // fail
+
+class V14(private[this] val x: Int) extends AnyVal // fail
+class V15(protected[this] val x: Int) extends AnyVal // fail
+
+class V16()(val a: Any) extends AnyVal // fail, was allowed 2.10.x
diff --git a/test/files/run/t7859/A_1.scala b/test/files/run/t7859/A_1.scala
new file mode 100644
index 0000000000..74f0709d4d
--- /dev/null
+++ b/test/files/run/t7859/A_1.scala
@@ -0,0 +1,11 @@
+class A(private val x: Int) extends AnyVal
+
+object A {
+  val Const = new A(0)
+}
+
+class A1(protected val x: Int) extends AnyVal
+
+package p {
+  class A2(private[p] val x: Int) extends AnyVal
+}
diff --git a/test/files/run/t7859/B_2.scala b/test/files/run/t7859/B_2.scala
new file mode 100644
index 0000000000..6b23af3abb
--- /dev/null
+++ b/test/files/run/t7859/B_2.scala
@@ -0,0 +1,47 @@
+class B private (private val b: Int) extends AnyVal
+object B {
+  val Const = new B(0)
+}
+
+// These tests will require erasure to unbox the value class.
+// We need to test under joint and separate compilation to check
+// that the 'notPRIVATE' flag on the param accessor is pickled.
+//
+// See also SI-6601.
+object Test {
+  def main(args: Array[String]) {
+    unboxA
+    unboxA1
+    unboxA2
+    unboxB
+  }
+
+  def unboxA {
+    val o: Some[A] = Some(A.Const)
+    val a = o.get
+    def id(a: A): A = a
+    id(a)
+  }
+
+  def unboxA1 {
+    val o: Some[A1] = Some(new A1(0))
+    val a = o.get
+    def id(a: A1): A1 = a
+    id(a)
+  }
+
+  def unboxA2 {
+    import p.A2
+    val o: Some[A2] = Some(new A2(0))
+    val a = o.get
+    def id(a: A2): A2 = a
+    id(a)
+  }
+
+  def unboxB {
+    val o: Some[B] = Some(B.Const)
+    val b = o.get
+    def id(b: B): B = b
+    id(b)
+  }
+}