14 files changed, 70 insertions, 14 deletions
diff --git a/src/library/scala/collection/TraversableLike.scala b/src/library/scala/collection/TraversableLike.scala
index a55257d128..fdbc5e9857 100644
--- a/src/library/scala/collection/TraversableLike.scala
+++ b/src/library/scala/collection/TraversableLike.scala
@@ -77,7 +77,7 @@ trait TraversableLike[+A, +Repr] extends Any
   import Traversable.breaks._
 
   /** The type implementing this traversable */
-  protected type Self = Repr
+  protected[this] type Self = Repr
 
   /** The collection of type $coll underlying this `TraversableLike` object.
    *  By default this is implemented as the `TraversableLike` object itself,
diff --git a/src/library/scala/collection/generic/GenericClassTagCompanion.scala b/src/library/scala/collection/generic/GenericClassTagCompanion.scala
index a587bbf544..76c12d118e 100644
--- a/src/library/scala/collection/generic/GenericClassTagCompanion.scala
+++ b/src/library/scala/collection/generic/GenericClassTagCompanion.scala
@@ -19,7 +19,7 @@ import scala.reflect.ClassTag
  *  @author Aleksandar Prokopec
  */
 abstract class GenericClassTagCompanion[+CC[X] <: Traversable[X]] {
-  type Coll = CC[_]
+  protected[this] type Coll = CC[_]
 
   def newBuilder[A](implicit ord: ClassTag[A]): Builder[A, CC[A]]
 
diff --git a/src/library/scala/collection/generic/GenericCompanion.scala b/src/library/scala/collection/generic/GenericCompanion.scala
index 5b03f8e5c6..b966ce51db 100644
--- a/src/library/scala/collection/generic/GenericCompanion.scala
+++ b/src/library/scala/collection/generic/GenericCompanion.scala
@@ -24,7 +24,7 @@ import scala.language.higherKinds
  */
 abstract class GenericCompanion[+CC[X] <: GenTraversable[X]] {
   /** The underlying collection type with unknown element type */
-  type Coll = CC[_]
+  protected[this] type Coll = CC[_]
 
   /** The default builder for `$Coll` objects.
    *  @tparam A      the type of the ${coll}'s elements
diff --git a/src/library/scala/collection/generic/GenericOrderedCompanion.scala b/src/library/scala/collection/generic/GenericOrderedCompanion.scala
index a9a50a1c35..094912c75a 100644
--- a/src/library/scala/collection/generic/GenericOrderedCompanion.scala
+++ b/src/library/scala/collection/generic/GenericOrderedCompanion.scala
@@ -19,7 +19,7 @@ import scala.language.higherKinds
  *  @since 2.8
  */
 abstract class GenericOrderedCompanion[+CC[X] <: Traversable[X]] {
-  type Coll = CC[_]
+  protected[this] type Coll = CC[_]
 
   def newBuilder[A](implicit ord: Ordering[A]): Builder[A, CC[A]]
 
diff --git a/src/library/scala/collection/immutable/TrieIterator.scala b/src/library/scala/collection/immutable/TrieIterator.scala
index f117bddb8c..550f4cd7e0 100644
--- a/src/library/scala/collection/immutable/TrieIterator.scala
+++ b/src/library/scala/collection/immutable/TrieIterator.scala
@@ -46,7 +46,7 @@ private[collection] abstract class TrieIterator[+T](elems: Array[Iterable[T]]) e
     case x: HashSetCollision1[_]    => x.ks.map(x => HashSet(x)).toArray
   }).asInstanceOf[Array[Iterable[T]]]
 
-  private type SplitIterators = ((Iterator[T], Int), Iterator[T])
+  private[this] type SplitIterators = ((Iterator[T], Int), Iterator[T])
 
   private def isTrie(x: AnyRef) = x match {
     case _: HashTrieMap[_,_] | _: HashTrieSet[_] => true
diff --git a/src/library/scala/collection/parallel/ParSeqLike.scala b/src/library/scala/collection/parallel/ParSeqLike.scala
index 201b624c72..874cf6fee9 100644
--- a/src/library/scala/collection/parallel/ParSeqLike.scala
+++ b/src/library/scala/collection/parallel/ParSeqLike.scala
@@ -44,8 +44,8 @@ trait ParSeqLike[+T, +Repr <: ParSeq[T], +Sequential <: Seq[T] with SeqLike[T, S
 extends scala.collection.GenSeqLike[T, Repr]
    with ParIterableLike[T, Repr, Sequential] {
 self =>
-  
-  type SuperParIterator = IterableSplitter[T]
+
+  protected[this] type SuperParIterator = IterableSplitter[T]
 
   /** A more refined version of the iterator found in the `ParallelIterable` trait,
    *  this iterator can be split into arbitrary subsets of iterators.
diff --git a/src/reflect/scala/reflect/internal/Symbols.scala b/src/reflect/scala/reflect/internal/Symbols.scala
index e14c617f24..0127bd988b 100644
--- a/src/reflect/scala/reflect/internal/Symbols.scala
+++ b/src/reflect/scala/reflect/internal/Symbols.scala
@@ -900,7 +900,7 @@ trait Symbols extends api.Symbols { self: SymbolTable =>
     }
 
     /** The variance of this symbol. */
-    final def variance: Variance =
+    def variance: Variance =
       if (isCovariant) Covariant
       else if (isContravariant) Contravariant
       else Invariant
@@ -2635,6 +2635,9 @@ trait Symbols extends api.Symbols { self: SymbolTable =>
   class AliasTypeSymbol protected[Symbols] (initOwner: Symbol, initPos: Position, initName: TypeName)
   extends TypeSymbol(initOwner, initPos, initName) {
     type TypeOfClonedSymbol = TypeSymbol
+    override def variance = if (hasLocalFlag) Bivariant else info.typeSymbol.variance
+    override def isContravariant = variance.isContravariant
+    override def isCovariant     = variance.isCovariant
     final override def isAliasType = true
     override def cloneSymbolImpl(owner: Symbol, newFlags: Long): TypeSymbol =
       owner.newNonClassSymbol(name, pos, newFlags)
diff --git a/src/reflect/scala/reflect/internal/Variances.scala b/src/reflect/scala/reflect/internal/Variances.scala
index df0a502b30..739dd69992 100644
--- a/src/reflect/scala/reflect/internal/Variances.scala
+++ b/src/reflect/scala/reflect/internal/Variances.scala
@@ -73,9 +73,8 @@ trait Variances {
         def nextVariance(sym: Symbol, v: Variance): Variance = (
           if (shouldFlip(sym, tvar)) v.flip
           else if (isLocalOnly(sym)) Bivariant
-          else if (!sym.isAliasType) v
-          else if (sym.isOverridingSymbol) Invariant
-          else Bivariant
+          else if (sym.isAliasType) Invariant
+          else v
         )
         def loop(sym: Symbol, v: Variance): Variance = (
           if (sym == tvar.owner || v.isBivariant) v
@@ -145,12 +144,12 @@ trait Variances {
         || sym.owner.isCaseApplyOrUnapply
       )
       tree match {
+        case defn: MemberDef if skip =>
+          log(s"Skipping variance check of ${sym.defString}")
         case ClassDef(_, _, _, _) | TypeDef(_, _, _, _) =>
           validateVariance(sym)
           super.traverse(tree)
         // ModuleDefs need not be considered because they have been eliminated already
-        case defn: ValOrDefDef if skip =>
-          log(s"Skipping variance check of $sym")
         case ValDef(_, _, _, _) =>
           validateVariance(sym)
         case DefDef(_, _, tparams, vparamss, _, _) =>
diff --git a/test/files/neg/t6566a.check b/test/files/neg/t6566a.check
new file mode 100644
index 0000000000..7668f9d2fb
--- /dev/null
+++ b/test/files/neg/t6566a.check
@@ -0,0 +1,4 @@
+t6566a.scala:2: error: covariant type T occurs in invariant position in type T of type MyType
+  class TypeCheat[+T] { type MyType = T }
+                             ^
+one error found
diff --git a/test/files/neg/t6566a.scala b/test/files/neg/t6566a.scala
new file mode 100644
index 0000000000..74a0b38e56
--- /dev/null
+++ b/test/files/neg/t6566a.scala
@@ -0,0 +1,17 @@
+object WhatsYourTypeIsMyType {
+  class TypeCheat[+T] { type MyType = T }
+
+  class Foo {
+    val tc = new TypeCheat[Foo]
+    var x: tc.MyType = _
+    def setX() = x = new Foo
+  }
+  class Bar extends Foo {
+    override val tc = new TypeCheat[Bar]
+    def unsound = this
+
+    setX()
+    println(x.unsound)
+  }
+  def main(args: Array[String]): Unit = new Bar
+}
diff --git a/test/files/neg/t6566b.check b/test/files/neg/t6566b.check
new file mode 100644
index 0000000000..fb3fe81fca
--- /dev/null
+++ b/test/files/neg/t6566b.check
@@ -0,0 +1,4 @@
+t6566b.scala:3: error: covariant type T occurs in invariant position in type T of type MyType
+    type MyType = T
+         ^
+one error found
diff --git a/test/files/neg/t6566b.scala b/test/files/neg/t6566b.scala
new file mode 100644
index 0000000000..18ddebf88b
--- /dev/null
+++ b/test/files/neg/t6566b.scala
@@ -0,0 +1,19 @@
+object WhatsYourTypeIsMyType {
+  trait WithMyType[+T] {
+    type MyType = T
+  }
+
+  class Foo extends WithMyType[Foo] {
+    var x: MyType = _
+    def setX() = x = new Foo
+  }
+
+  class Bar extends Foo with WithMyType[Bar] {
+    def unsound { println("iAmABar") }
+
+    setX()
+    println(x.unsound)
+  }
+
+  def main(args: Array[String]): Unit = new Bar
+}
diff --git a/test/files/neg/variances.check b/test/files/neg/variances.check
index 0643e533b7..7d965e94dc 100644
--- a/test/files/neg/variances.check
+++ b/test/files/neg/variances.check
@@ -13,7 +13,10 @@ variances.scala:21: error: covariant type A occurs in invariant position in supe
 variances.scala:74: error: covariant type A occurs in contravariant position in type => test.Covariant.T[A]{val m: A => A} of value x
     val x: T[A] {
         ^
+variances.scala:89: error: covariant type T occurs in invariant position in type T of type A
+    type A = T
+         ^
 variances.scala:90: error: covariant type T occurs in contravariant position in type => test.TestAlias.B[C.this.A] of method foo
     def foo: B[A]
         ^
-6 errors found
+7 errors found
diff --git a/test/files/pos/variances-local.scala b/test/files/pos/variances-local.scala
new file mode 100644
index 0000000000..35e395095c
--- /dev/null
+++ b/test/files/pos/variances-local.scala
@@ -0,0 +1,7 @@
+class Foo1[+T] {
+  private[this] type MyType = T
+}
+
+class Foo2[+T] {
+  protected[this] type MyType = T
+}