Fix scala#580: use isContainedIn to support cases where the enclosing class is also the top-level class

Author: smarter

src/dotty/tools/dotc/transform/LambdaLift.scala

@@ -292,7 +292,7 @@ class LambdaLift extends MiniPhase with IdentityDenotTransformer { thisTransform
             val encClass = local.enclosingClass
             val topClass = local.topLevelClass
               // member of a static object
-            if (encClass.isStatic && encClass.isProperlyContainedIn(topClass)) {
+            if (encClass.isStatic && encClass.isContainedIn(topClass)) {
                // though the second condition seems weird, it's not true for symbols which are defined in some
                // weird combinations of super calls.
               (encClass, EmptyFlags)

tests/run/innerInObject.check

@@ -0,0 +1,2 @@
+1
+2

tests/run/innerInObject.scala

@@ -0,0 +1,24 @@
+object Test {
+  def foo(x: Int) = {
+    println(x)
+  }
+
+  def outer(x: Int) = {
+    def inner() = {
+      foo(x)
+    }
+    inner()
+  }
+
+  def outer2(x: Int) = {
+    def inner2() = {
+      Test.foo(x)
+    }
+    inner2()
+  }
+
+  def main(args: Array[String]): Unit = {
+    outer(1)
+    outer2(2)
+  }
+}