public static void clean(PsiElement expression) {
    expression.accept(new JavaRecursiveElementWalkingVisitor() {
      @Override
      public void visitElement(@NotNull PsiElement element) {
        if (element instanceof PsiExpression) {
          element.putCopyableUserData(SELF_REFERENCE, null);
        }
        super.visitElement(element);
      }
    });
  }
public static void clean(PsiElement expression)