public final AntlrPilarParser.constElement_return constElement()
      throws RecognitionException {
    AntlrPilarParser.constElement_return retval = new AntlrPilarParser.constElement_return();
    retval.start = input.LT(1);
    int constElement_StartIndex = input.index();
    Object root_0 = null;

    Token t = null;
    Token char_literal64 = null;
    Token char_literal67 = null;
    AntlrPilarParser.exp_return exp65 = null;

    AntlrPilarParser.annotationList_return annotationList66 = null;

    Object t_tree = null;
    Object char_literal64_tree = null;
    Object char_literal67_tree = null;
    RewriteRuleTokenStream stream_175 = new RewriteRuleTokenStream(adaptor,
        "token 175");
    RewriteRuleTokenStream stream_173 = new RewriteRuleTokenStream(adaptor,
        "token 173");
    RewriteRuleTokenStream stream_ID = new RewriteRuleTokenStream(adaptor,
        "token ID");
    RewriteRuleSubtreeStream stream_exp = new RewriteRuleSubtreeStream(adaptor,
        "rule exp");
    RewriteRuleSubtreeStream stream_annotationList = new RewriteRuleSubtreeStream(
        adaptor, "rule annotationList");
    try {
      if (state.backtracking > 0 && alreadyParsedRule(input, 21)) {
        return retval;
      }
      // /Users/robby/Repositories/sireum-parser/sireum-parser/src/main/java/org/sireum/pilar/parser/AntlrPilar.g:266:2: (t= ID '=' exp annotationList ';' -> ^( CONST_ELEMENT[$t] ID exp annotationList ) )
      // /Users/robby/Repositories/sireum-parser/sireum-parser/src/main/java/org/sireum/pilar/parser/AntlrPilar.g:266:4: t= ID '=' exp annotationList ';'
      {
        t = (Token) match(input, ID, FOLLOW_ID_in_constElement1907);
        if (state.failed) return retval;
        if (state.backtracking == 0) stream_ID.add(t);

        char_literal64 = (Token) match(
            input,
            173,
            FOLLOW_173_in_constElement1909);
        if (state.failed) return retval;
        if (state.backtracking == 0) stream_173.add(char_literal64);

        pushFollow(FOLLOW_exp_in_constElement1914);
        exp65 = exp();

        state._fsp--;
        if (state.failed) return retval;
        if (state.backtracking == 0) stream_exp.add(exp65.getTree());
        pushFollow(FOLLOW_annotationList_in_constElement1916);
        annotationList66 = annotationList();

        state._fsp--;
        if (state.failed) return retval;
        if (state.backtracking == 0)
          stream_annotationList.add(annotationList66.getTree());
        char_literal67 = (Token) match(
            input,
            175,
            FOLLOW_175_in_constElement1918);
        if (state.failed) return retval;
        if (state.backtracking == 0) stream_175.add(char_literal67);

        // AST REWRITE
        // elements: ID, annotationList, exp
        // token labels: 
        // rule labels: retval
        // token list labels: 
        // rule list labels: 
        // wildcard labels: 
        if (state.backtracking == 0) {
          retval.tree = root_0;
          RewriteRuleSubtreeStream stream_retval = new RewriteRuleSubtreeStream(
              adaptor, "rule retval", retval != null ? retval.tree : null);

          root_0 = (Object) adaptor.nil();
          // 267:41: -> ^( CONST_ELEMENT[$t] ID exp annotationList )
          {
            // /Users/robby/Repositories/sireum-parser/sireum-parser/src/main/java/org/sireum/pilar/parser/AntlrPilar.g:267:44: ^( CONST_ELEMENT[$t] ID exp annotationList )
            {
              Object root_1 = (Object) adaptor.nil();
              root_1 = (Object) adaptor.becomeRoot(
                  (Object) adaptor.create(CONST_ELEMENT, t),
                  root_1);

              adaptor.addChild(root_1, stream_ID.nextNode());
              adaptor.addChild(root_1, stream_exp.nextTree());
              adaptor.addChild(root_1, stream_annotationList.nextTree());

              adaptor.addChild(root_0, root_1);
            }

          }

          retval.tree = root_0;
        }
      }

      retval.stop = input.LT(-1);

      if (state.backtracking == 0) {

        retval.tree = (Object) adaptor.rulePostProcessing(root_0);
        adaptor.setTokenBoundaries(retval.tree, retval.start, retval.stop);
      }
    } catch (RecognitionException re) {
      reportError(re);
      recover(input, re);
      retval.tree = (Object) adaptor.errorNode(
          input,
          retval.start,
          input.LT(-1),
          re);

    } finally {
      if (state.backtracking > 0) {
        memoize(input, 21, constElement_StartIndex);
      }
    }
    return retval;
  }