4 files changed, 58 insertions, 2 deletions
diff --git a/src/reflect/scala/reflect/internal/BaseTypeSeqs.scala b/src/reflect/scala/reflect/internal/BaseTypeSeqs.scala
index 19c67879f5..0ca8611719 100644
--- a/src/reflect/scala/reflect/internal/BaseTypeSeqs.scala
+++ b/src/reflect/scala/reflect/internal/BaseTypeSeqs.scala
@@ -166,9 +166,10 @@ trait BaseTypeSeqs {
       val index = new Array[Int](nparents)
       var i = 0
       for (p <- parents) {
+        val parentBts = p.dealias.baseTypeSeq // dealias need for SI-8046.
         pbtss(i) =
-          if (p.baseTypeSeq eq undetBaseTypeSeq) AnyClass.info.baseTypeSeq
-          else p.baseTypeSeq
+          if (parentBts eq undetBaseTypeSeq) AnyClass.info.baseTypeSeq
+          else parentBts
         index(i) = 0
         i += 1
       }
diff --git a/test/files/pos/t8046.scala b/test/files/pos/t8046.scala
new file mode 100644
index 0000000000..304d70b6b8
--- /dev/null
+++ b/test/files/pos/t8046.scala
@@ -0,0 +1,20 @@
+trait One {
+  type Op[A]
+  type Alias[A] = Op[A]
+}
+ 
+trait Two extends One {
+  trait Op[A] extends (A => A)
+ 
+  // This compiles
+  class View1 extends Op[Int] { def apply(xs: Int) = xs }
+ 
+  // ??? base class View2 not found in basetypes of class View2
+  // ./a.scala:9: error: class View2 needs to be abstract, since \
+  //   method apply in trait Function1 of type (v1: T1)R is not defined
+  // (Note that T1 does not match Int)
+  //   class View2 extends Alias[Int] { def apply(xs: Int) = xs }
+  //         ^
+  // one error found
+  class View2 extends Alias[Int] { def apply(xs: Int) = xs }
+}
diff --git a/test/files/pos/t8046b.scala b/test/files/pos/t8046b.scala
new file mode 100644
index 0000000000..45b99fd7e0
--- /dev/null
+++ b/test/files/pos/t8046b.scala
@@ -0,0 +1,16 @@
+trait One {
+  type Op[A]
+  type Alias = Op[Int]
+}
+ 
+trait Two extends One {
+  trait Op[A] extends M[A]
+  //(a: Alias) => a.value.toChar               // okay
+                                             // (=> A).asSeenFrom(a.type, trait M): => Int
+  class View2 extends Alias { value.toChar } // toChar is not a member of type parameter A
+                                             // (=> A).asSeenFrom(View2.this.type, trait M): => A
+  
+  // override type Alias = Op[Int]           // works with this
+}
+
+trait M[A] { def value: A = sys.error("") }
diff --git a/test/pending/pos/t8046c.scala b/test/pending/pos/t8046c.scala
new file mode 100644
index 0000000000..9a8616828d
--- /dev/null
+++ b/test/pending/pos/t8046c.scala
@@ -0,0 +1,19 @@
+trait One {
+  type Op[A]
+  type Alias[A] = Op[A]
+}
+
+trait Three extends One {
+  trait Op[A] extends (A => A)
+ 
+  def f1(f: Op[Int])            = f(5)
+  def f2(f: Alias[Int])         = f(5)
+  def f3[T <: Op[Int]](f: T)    = f(5)
+  def f4[T <: Alias[Int]](f: T) = f(5)
+  // ./a.scala:12: error: type mismatch;
+  //  found   : Int(5)
+  //  required: T1
+  //   def f4[T <: Alias[Int]](f: T) = f(5)
+  //                                     ^
+}
+