close #4524 and close #4425, review by odersky.

4 files changed, 23 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala b/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
index 5b4a5b3c44..8e286ca983 100644
--- a/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
@@ -189,7 +189,12 @@ trait NamesDefaults { self: Analyzer =>
         } else {
           val module = companionModuleOf(baseFun.symbol.owner, context)
           if (module == NoSymbol) None
-          else Some(atPos(pos.focus)(gen.mkAttributedRef(pre, module)))
+          else {
+            val ref = atPos(pos.focus)(gen.mkAttributedRef(pre, module))
+            if (module.isStable && pre.isStable)    // fixes #4524. the type checker does the same for
+              ref.setType(singleType(pre, module))  // typedSelect, it calls "stabilize" on the result.
+            Some(ref)
+          }
         }
       }
 
diff --git a/test/files/neg/t4425.check b/test/files/neg/t4425.check
new file mode 100644
index 0000000000..4ff4b1eec0
--- /dev/null
+++ b/test/files/neg/t4425.check
@@ -0,0 +1,4 @@
+t4425.scala:3: error: erroneous or inaccessible type
+  42 match { case _ X _ => () }
+                    ^
+one error found
diff --git a/test/files/neg/t4425.scala b/test/files/neg/t4425.scala
new file mode 100644
index 0000000000..d8cc6922f7
--- /dev/null
+++ b/test/files/neg/t4425.scala
@@ -0,0 +1,4 @@
+object Foo {
+  object X { def unapply(x : Int)(y : Option[Int] = None) = None }
+  42 match { case _ X _ => () }
+}
diff --git a/test/files/pos/t4524.scala b/test/files/pos/t4524.scala
new file mode 100644
index 0000000000..4721a7d067
--- /dev/null
+++ b/test/files/pos/t4524.scala
@@ -0,0 +1,9 @@
+object test {
+  import A._
+  class A(b: B = new A.B())
+  object A {
+    class B
+    new A()
+  }
+}
+