close #3946.

7 files changed, 53 insertions, 31 deletions

diff --git a/src/compiler/scala/tools/ant/Scaladoc.scala b/src/compiler/scala/tools/ant/Scaladoc.scala
index 3d96b959f5..427846fa33 100644
--- a/src/compiler/scala/tools/ant/Scaladoc.scala
+++ b/src/compiler/scala/tools/ant/Scaladoc.scala
@@ -385,7 +385,7 @@ class Scaladoc extends MatchingTask {
   /** This is forwarding method to circumvent bug #281 in Scala 2. Remove when
    *  bug has been corrected.
    */
-  override protected def getDirectoryScanner(baseDir: java.io.File) =
+  override def getDirectoryScanner(baseDir: java.io.File) =
     super.getDirectoryScanner(baseDir)
 
   /** Transforms a string name into a file relative to the provided base
diff --git a/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala b/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
index 6d846eec10..b006b2a30e 100644
--- a/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
+++ b/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
@@ -1302,6 +1302,11 @@ abstract class ClassfileParser {
       // apparently occurs when processing v45.3 bytecode.
       if (sym.toplevelClass != NoSymbol)
         sym.privateWithin = sym.toplevelClass.owner
+
+    // protected in java means package protected. #3946
+    if ((jflags & JAVA_ACC_PROTECTED) != 0)
+      if (sym.toplevelClass != NoSymbol)
+        sym.privateWithin = sym.toplevelClass.owner
   }
 
   @inline final private def isPrivate(flags: Int) =
diff --git a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
index 5711117fea..dfe07ed33b 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
@@ -408,37 +408,41 @@ abstract class SuperAccessors extends transform.Transform with transform.TypingT
      * classes, this has to be signaled as error.
      */
     private def needsProtectedAccessor(sym: Symbol, pos: Position): Boolean = {
-      def errorRestriction(msg: String) {
-        unit.error(pos, "Implementation restriction: " + msg)
+      val clazz = currentOwner.enclClass
+      def accessibleThroughSubclassing =
+        validCurrentOwner && clazz.thisSym.isSubClass(sym.owner) && !clazz.isTrait
+
+      def packageAccessBoundry(sym: Symbol) = {
+        val b = sym.accessBoundary(sym.owner)
+        if (b.isPackageClass) b
+        else b.enclosingPackageClass
       }
 
-      def accessibleThroughSubclassing: Boolean =
-        (validCurrentOwner
-            && currentOwner.enclClass.thisSym.isSubClass(sym.owner)
-            && !currentOwner.enclClass.isTrait)
-
-      val res = /* settings.debug.value && */
-      ((sym hasFlag PROTECTED)
-       && sym.hasFlag(JAVA)
-       && !sym.owner.isPackageClass
-       && !accessibleThroughSubclassing
-       && (sym.owner.enclosingPackageClass != currentOwner.enclosingPackageClass)
-       && (sym.owner.enclosingPackageClass == sym.accessBoundary(sym.owner).enclosingPackageClass))
-
-      if (res) {
-        val host = hostForAccessorOf(sym, currentOwner.enclClass)
-        // bug #1393 - as things stand now the "host" could be a package.
-        if (host.isPackageClass) false
-        else if (host.thisSym != host) {
-          if (host.thisSym.tpe.typeSymbol.hasFlag(JAVA))
-            errorRestriction("%s accesses protected %s from self type %s.".format(currentOwner.enclClass, sym, host.thisSym.tpe))
-          false
-        } else if (host.isTrait && sym.hasFlag(JAVA)) {
-            errorRestriction(("%s accesses protected %s inside a concrete trait method. " +
-                    "Add an accessor in a class extending %s to work around this bug.").format(currentOwner.enclClass, sym, sym.enclClass))
-            false
-        } else res
-      } else res
+      val isCandidate = (
+           sym.isProtected
+        && sym.isJavaDefined
+        && !sym.definedInPackage
+        && !accessibleThroughSubclassing
+        && (sym.owner.enclosingPackageClass != currentOwner.enclosingPackageClass)
+        && (sym.owner.enclosingPackageClass == packageAccessBoundry(sym))
+      )
+      val host = hostForAccessorOf(sym, clazz)
+      def isSelfType = !(host.tpe <:< host.typeOfThis) && {
+        if (host.typeOfThis.typeSymbol.isJavaDefined)
+          unit.error(pos, "Implementation restriction: " +
+            "%s accesses protected %s from self type %s.".format(clazz, sym, host.typeOfThis)
+          )
+        true
+      }
+      def isJavaProtected = host.isTrait && sym.isJavaDefined && {
+        unit.error(pos, "Implementation restriction: " +
+          """|%s accesses protected %s inside a concrete trait method.
+             |Add an accessor in a class extending %s as a workaround.""".stripMargin.format(
+                clazz, sym, sym.enclClass)
+        )
+        true
+      }
+      isCandidate && !host.isPackageClass && !isSelfType && !isJavaProtected
     }
 
     /** Return the innermost enclosing class C of referencingClass for which either
diff --git a/src/swing/scala/swing/RichWindow.scala b/src/swing/scala/swing/RichWindow.scala
index 10e396247e..dcad382a33 100644
--- a/src/swing/scala/swing/RichWindow.scala
+++ b/src/swing/scala/swing/RichWindow.scala
@@ -78,7 +78,7 @@ class Frame extends RichWindow {
   override lazy val peer: JFrame with InterfaceMixin = new JFrame with InterfaceMixin with SuperMixin
 
   protected trait SuperMixin extends JFrame {
-    override protected def processWindowEvent(e: java.awt.event.WindowEvent) {
+    override def processWindowEvent(e: java.awt.event.WindowEvent) {
       super.processWindowEvent(e)
       if (e.getID() == java.awt.event.WindowEvent.WINDOW_CLOSING)
         closeOperation()
diff --git a/test/files/neg/t3946.check b/test/files/neg/t3946.check
new file mode 100644
index 0000000000..6379b50dba
--- /dev/null
+++ b/test/files/neg/t3946.check
@@ -0,0 +1,5 @@
+S_1.scala:3: error: overriding method m in class J of type ()Unit;
+ method m has weaker access privileges; it should be at least protected[p]
+  override protected def m { }
+                         ^
+one error found
diff --git a/test/files/neg/t3946/J.java b/test/files/neg/t3946/J.java
new file mode 100644
index 0000000000..189b8e1d23
--- /dev/null
+++ b/test/files/neg/t3946/J.java
@@ -0,0 +1,4 @@
+package p;
+public class J {
+    protected void m() { return; }
+}
diff --git a/test/files/neg/t3946/S_1.scala b/test/files/neg/t3946/S_1.scala
new file mode 100644
index 0000000000..2c52094701
--- /dev/null
+++ b/test/files/neg/t3946/S_1.scala
@@ -0,0 +1,4 @@
+package p
+class S extends J {
+  override protected def m { }
+}