5 files changed, 55 insertions, 3 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 5bbc0b6430..97e07d9f3e 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -2566,10 +2566,13 @@ trait Typers extends Modes {
             val formals1 = formalTypes(formals0, args.length)
             if (sameLength(formals1, args)) {
               val args1 = typedArgs(args, mode, formals0, formals1)
-              assert(isFullyDefined(pt), tree+" ==> "+UnApply(fun1, args1)+", pt = "+pt)
+              // This used to be the following (failing) assert:
+              //   assert(isFullyDefined(pt), tree+" ==> "+UnApply(fun1, args1)+", pt = "+pt)
+              // I modified as follows.  See SI-1048.
+              val pt1 = if (isFullyDefined(pt)) pt else makeFullyDefined(pt)
 
-              val itype = glb(List(pt, arg.tpe))
-              arg.tpe = pt    // restore type (arg is a dummy tree, just needs to pass typechecking)
+              val itype = glb(List(pt1, arg.tpe))
+              arg.tpe = pt1    // restore type (arg is a dummy tree, just needs to pass typechecking)
               UnApply(fun1, args1) setPos tree.pos setType itype
             }
             else {
diff --git a/test/files/pos/bug1048.scala b/test/files/pos/bug1048.scala
new file mode 100644
index 0000000000..f88dbbc88b
--- /dev/null
+++ b/test/files/pos/bug1048.scala
@@ -0,0 +1,15 @@
+trait T[U] {
+  def x: T[V] forSome { type V <: U }
+}
+
+object T {
+  def unapply[U](t: T[U]): Option[T[V] forSome { type V <: U }] = Some(t.x)
+}
+
+object Test {
+  def f[W](t: T[W]) = t match {
+    case T(T(_)) => ()
+  }
+}
+
+
diff --git a/test/files/run/bug1048.check b/test/files/run/bug1048.check
new file mode 100644
index 0000000000..f1e5eeed2d
--- /dev/null
+++ b/test/files/run/bug1048.check
@@ -0,0 +1,2 @@
+3
+2
diff --git a/test/files/run/bug1048.scala b/test/files/run/bug1048.scala
new file mode 100644
index 0000000000..5eaeaa25c6
--- /dev/null
+++ b/test/files/run/bug1048.scala
@@ -0,0 +1,21 @@
+final case class W[A](v: A)
+
+object E {
+  def unapply(w: W[Any]): Option[Any] = None
+}
+
+object Bug {
+  def bug[A](e: Either[W[_], A]) = e match {
+    case Left(E(x)) => 1
+    case Right(x)   => 2
+    case _          => 3
+  }
+}
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    println(Bug.bug(Left(W(5))))
+    println(Bug.bug(Right(5)))
+  }
+}
+
diff --git a/test/pending/pos/unapplyGeneric.scala b/test/pending/pos/unapplyGeneric.scala
new file mode 100644
index 0000000000..bf88816885
--- /dev/null
+++ b/test/pending/pos/unapplyGeneric.scala
@@ -0,0 +1,11 @@
+object Bar {
+  def unapply[A,B](bar:Bar[A,B]) = Some(bar)
+}
+
+class Bar[A,B](val _1:A, val _2:B) extends Product2[A,B]
+
+object Test {
+  new Bar(2, 'a') match {
+    case Bar(x,y) =>
+  }
+}