Fix soundness test

Author: liufengyun

tests/init/neg/soundness1.scala

@@ -1,7 +1,29 @@
 class A(b: B) {
-  val b2 = new B(this) // error
+  val b2 = new B(this)
 }
 
 class B(a: A) {
-  val a2 = new A(this) // error
+  val a2 = new A(this)
 }
+
+object Test2:
+  class A(b: B) {
+    val b2 = new B(this)
+    val c = b2.a2
+  }
+
+  class B(a: A) {
+    val a2 = new A(this)
+    val c = a2.b2
+  }
+
+object Test3:
+  class A(b: B) {
+    println(b.a2)           // error
+    val b2 = new B(this)
+  }
+
+  class B(a: A) {
+    println(a.b2)           // error
+    val a2 = new A(this)
+  }

tests/init/neg/soundness2.scala

@@ -1,3 +1,4 @@
 class C(c: C) {
-  val c2 = new C(this)   // error
+  val d = c.c2          // error
+  val c2 = new C(this)
 }