static boolean isDefinitelySimple(@Nullable PsiExpression expression) {
    if (expression instanceof PsiLiteral) {
      return true;
    }
    if (expression instanceof PsiReferenceExpression) {
      PsiElement qualifier = ((PsiReferenceExpression)expression).getQualifier();
      if (qualifier instanceof PsiQualifiedExpression || !(qualifier instanceof PsiExpression)) {
        PsiElement resolved = ((PsiReferenceExpression)expression).resolve();
        return resolved instanceof PsiVariable || resolved instanceof PsiClass;
      }
    }
    return false;
  }
static boolean isDefinitelySimple(@Nullable PsiExpression expression)