Extract Function: Check for INVISIBLE_* errors during validation phase

#KT-4995 Fixed

idea/testData/refactoring/extractFunction/basic/privateMemberInClassObject.kt

@@ -0,0 +1,9 @@
+// SIBLING:
+public class A {
+    class object {
+        private val t: Int = 1
+    }
+    fun f() {
+        <selection>t</selection>
+    }
+}