Skip capture sets in checkNoPrivateLeaks when cc is not enabled

Author: noti0na1

compiler/src/dotty/tools/dotc/typer/Checking.scala

@@ -771,8 +771,9 @@ object Checking {
           !(symBoundary.isContainedIn(otherBoundary) ||
             otherLinkedBoundary.exists && symBoundary.isContainedIn(otherLinkedBoundary))
         }
-        && !(inCaptureSet && other.isAllOf(LocalParamAccessor))
-            // class parameters in capture sets are not treated as leaked since in
+        && !(inCaptureSet && (!Feature.ccEnabled || other.isAllOf(LocalParamAccessor)))
+            // All references are skipped in capture sets when CC is not enabled.
+            // Class parameters in capture sets are not treated as leaked since in
             // phase CheckCaptures these are treated as normal vals.
 
       def apply(tp: Type): Type = tp match {

tests/pos/i23885/S_1.scala

@@ -0,0 +1,4 @@
+import language.experimental.captureChecking
+
+class A:
+  def f(x: A^): A^{this, x} = ???

tests/pos/i23885/S_2.scala

@@ -0,0 +1,3 @@
+class B:
+  private val a: A = ???
+  def g(b: A) = a.f(b)