docs: public static Matcher<ExpressionTree> nonNullLiteral() {
      return new Matcher<ExpressionTree>() {
        @Override
        public boolean matches(ExpressionTree tree, VisitorState state) {
          switch (tree.getKind()) {
            case MEMBER_SELECT:
              return ((MemberSelectTree) tree).getIdentifier().contentEquals("class");
            case INT_LITERAL:
            case LONG_LITERAL:
            case FLOAT_LITERAL:
            case DOUBLE_LITERAL:
            case BOOLEAN_LITERAL:
            case CHAR_LITERAL:
              // fall through
            case STRING_LITERAL:
              return true;
            default:
              return false;
          }
        }
      };
    }