DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (12c0bcb999c5)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef frontend_ParseNode_h
#define frontend_ParseNode_h

#include "mozilla/Attributes.h"

#include "frontend/Token.h"
#include "vm/BigIntType.h"
#include "vm/BytecodeUtil.h"
#include "vm/Printer.h"
#include "vm/Scope.h"

/* clang-format off */
//
// A few notes on lifetime of ParseNode trees:
//
// - All the `ParseNode` instances MUST BE explicitly allocated in the context's `LifoAlloc`.
//   This is typically implemented by the `FullParseHandler` or it can be reimplemented with
//   a custom `new_`.
//
// - The tree is bulk-deallocated when the parser is deallocated. Consequently, references
//   to a subtree MUST NOT exist once the parser has been deallocated.
//
// - This bulk-deallocation DOES NOT run destructors.
//
// - Instances of `LexicalScope::Data` MUST BE allocated as instances of `ParseNode`, in the same
//   `LifoAlloc`. They are bulk-deallocated alongside the rest of the tree.
//
// - Instances of `JSAtom` used throughout the tree (including instances of `PropertyName`) MUST
//   be kept alive by the parser. This is done through an instance of `AutoKeepAtoms` held by
//   the parser.
//
// - Once the parser is deallocated, the `JSAtom` instances MAY be garbage-collected.
//
/* clang-format on */

namespace js {
namespace frontend {

class ParseContext;
class FullParseHandler;
class FunctionBox;
class ObjectBox;
class BigIntBox;

#define FOR_EACH_PARSE_NODE_KIND(F)                                          \
  F(EmptyStmt, NullaryNode)                                                  \
  F(ExpressionStmt, UnaryNode)                                               \
  F(CommaExpr, ListNode)                                                     \
  F(ConditionalExpr, ConditionalExpression)                                  \
  F(PropertyDefinition, PropertyDefinition)                                  \
  F(Shorthand, BinaryNode)                                                   \
  F(PosExpr, UnaryNode)                                                      \
  F(NegExpr, UnaryNode)                                                      \
  F(PreIncrementExpr, UnaryNode)                                             \
  F(PostIncrementExpr, UnaryNode)                                            \
  F(PreDecrementExpr, UnaryNode)                                             \
  F(PostDecrementExpr, UnaryNode)                                            \
  F(PropertyNameExpr, NameNode)                                              \
  F(DotExpr, PropertyAccess)                                                 \
  F(ElemExpr, PropertyByValue)                                               \
  F(ArrayExpr, ListNode)                                                     \
  F(Elision, NullaryNode)                                                    \
  F(StatementList, ListNode)                                                 \
  F(LabelStmt, LabeledStatement)                                             \
  F(ObjectExpr, ListNode)                                                    \
  F(CallExpr, BinaryNode)                                                    \
  F(Arguments, ListNode)                                                     \
  F(Name, NameNode)                                                          \
  F(ObjectPropertyName, NameNode)                                            \
  F(PrivateName, NameNode)                                                   \
  F(ComputedName, UnaryNode)                                                 \
  F(NumberExpr, NumericLiteral)                                              \
  F(BigIntExpr, BigIntLiteral)                                               \
  F(StringExpr, NameNode)                                                    \
  F(TemplateStringListExpr, ListNode)                                        \
  F(TemplateStringExpr, NameNode)                                            \
  F(TaggedTemplateExpr, BinaryNode)                                          \
  F(CallSiteObj, CallSiteNode)                                               \
  F(RegExpExpr, RegExpLiteral)                                               \
  F(TrueExpr, BooleanLiteral)                                                \
  F(FalseExpr, BooleanLiteral)                                               \
  F(NullExpr, NullLiteral)                                                   \
  F(RawUndefinedExpr, RawUndefinedLiteral)                                   \
  F(ThisExpr, UnaryNode)                                                     \
  F(Function, FunctionNode)                                                  \
  F(Module, ModuleNode)                                                      \
  F(IfStmt, TernaryNode)                                                     \
  F(SwitchStmt, SwitchStatement)                                             \
  F(Case, CaseClause)                                                        \
  F(WhileStmt, BinaryNode)                                                   \
  F(DoWhileStmt, BinaryNode)                                                 \
  F(ForStmt, ForNode)                                                        \
  F(BreakStmt, BreakStatement)                                               \
  F(ContinueStmt, ContinueStatement)                                         \
  F(VarStmt, ListNode)                                                       \
  F(ConstDecl, ListNode)                                                     \
  F(WithStmt, BinaryNode)                                                    \
  F(ReturnStmt, UnaryNode)                                                   \
  F(NewExpr, BinaryNode)                                                     \
  /* Delete operations.  These must be sequential. */                        \
  F(DeleteNameExpr, UnaryNode)                                               \
  F(DeletePropExpr, UnaryNode)                                               \
  F(DeleteElemExpr, UnaryNode)                                               \
  F(DeleteExpr, UnaryNode)                                                   \
  F(TryStmt, TernaryNode)                                                    \
  F(Catch, BinaryNode)                                                       \
  F(ThrowStmt, UnaryNode)                                                    \
  F(DebuggerStmt, DebuggerStatement)                                         \
  F(Generator, NullaryNode)                                                  \
  F(InitialYield, UnaryNode)                                                 \
  F(YieldExpr, UnaryNode)                                                    \
  F(YieldStarExpr, UnaryNode)                                                \
  F(LexicalScope, LexicalScopeNode)                                          \
  F(LetDecl, ListNode)                                                       \
  F(ImportDecl, BinaryNode)                                                  \
  F(ImportSpecList, ListNode)                                                \
  F(ImportSpec, BinaryNode)                                                  \
  F(ExportStmt, UnaryNode)                                                   \
  F(ExportFromStmt, BinaryNode)                                              \
  F(ExportDefaultStmt, BinaryNode)                                           \
  F(ExportSpecList, ListNode)                                                \
  F(ExportSpec, BinaryNode)                                                  \
  F(ExportBatchSpecStmt, NullaryNode)                                        \
  F(ForIn, TernaryNode)                                                      \
  F(ForOf, TernaryNode)                                                      \
  F(ForHead, TernaryNode)                                                    \
  F(ParamsBody, ListNode)                                                    \
  F(Spread, UnaryNode)                                                       \
  F(MutateProto, UnaryNode)                                                  \
  F(ClassDecl, ClassNode)                                                    \
  F(ClassMethod, ClassMethod)                                                \
  F(ClassField, ClassField)                                                  \
  F(ClassMemberList, ListNode)                                               \
  F(ClassNames, ClassNames)                                                  \
  F(NewTargetExpr, BinaryNode)                                               \
  F(PosHolder, NullaryNode)                                                  \
  F(SuperBase, UnaryNode)                                                    \
  F(SuperCallExpr, BinaryNode)                                               \
  F(SetThis, BinaryNode)                                                     \
  F(ImportMetaExpr, BinaryNode)                                              \
  F(CallImportExpr, BinaryNode)                                              \
  F(InitExpr, BinaryNode)                                                    \
                                                                             \
  /* Unary operators. */                                                     \
  F(TypeOfNameExpr, UnaryNode)                                               \
  F(TypeOfExpr, UnaryNode)                                                   \
  F(VoidExpr, UnaryNode)                                                     \
  F(NotExpr, UnaryNode)                                                      \
  F(BitNotExpr, UnaryNode)                                                   \
  F(AwaitExpr, UnaryNode)                                                    \
                                                                             \
  /*                                                                         \
   * Binary operators.                                                       \
   * These must be in the same order as TOK_OR and friends in TokenStream.h. \
   */                                                                        \
  F(PipelineExpr, ListNode)                                                  \
  F(OrExpr, ListNode)                                                        \
  F(AndExpr, ListNode)                                                       \
  F(BitOrExpr, ListNode)                                                     \
  F(BitXorExpr, ListNode)                                                    \
  F(BitAndExpr, ListNode)                                                    \
  F(StrictEqExpr, ListNode)                                                  \
  F(EqExpr, ListNode)                                                        \
  F(StrictNeExpr, ListNode)                                                  \
  F(NeExpr, ListNode)                                                        \
  F(LtExpr, ListNode)                                                        \
  F(LeExpr, ListNode)                                                        \
  F(GtExpr, ListNode)                                                        \
  F(GeExpr, ListNode)                                                        \
  F(InstanceOfExpr, ListNode)                                                \
  F(InExpr, ListNode)                                                        \
  F(LshExpr, ListNode)                                                       \
  F(RshExpr, ListNode)                                                       \
  F(UrshExpr, ListNode)                                                      \
  F(AddExpr, ListNode)                                                       \
  F(SubExpr, ListNode)                                                       \
  F(MulExpr, ListNode)                                                       \
  F(DivExpr, ListNode)                                                       \
  F(ModExpr, ListNode)                                                       \
  F(PowExpr, ListNode)                                                       \
                                                                             \
  /* Assignment operators (= += -= etc.). */                                 \
  /* AssignmentNode::test assumes all these are consecutive. */              \
  F(AssignExpr, AssignmentNode)                                              \
  F(AddAssignExpr, AssignmentNode)                                           \
  F(SubAssignExpr, AssignmentNode)                                           \
  F(BitOrAssignExpr, AssignmentNode)                                         \
  F(BitXorAssignExpr, AssignmentNode)                                        \
  F(BitAndAssignExpr, AssignmentNode)                                        \
  F(LshAssignExpr, AssignmentNode)                                           \
  F(RshAssignExpr, AssignmentNode)                                           \
  F(UrshAssignExpr, AssignmentNode)                                          \
  F(MulAssignExpr, AssignmentNode)                                           \
  F(DivAssignExpr, AssignmentNode)                                           \
  F(ModAssignExpr, AssignmentNode)                                           \
  F(PowAssignExpr, AssignmentNode)

/*
 * Parsing builds a tree of nodes that directs code generation.  This tree is
 * not a concrete syntax tree in all respects (for example, || and && are left
 * associative, but (A && B && C) translates into the right-associated tree
 * <A && <B && C>> so that code generation can emit a left-associative branch
 * around <B && C> when A is false).  Nodes are labeled by kind.
 *
 * The long comment after this enum block describes the kinds in detail.
 */
enum class ParseNodeKind : uint16_t {
#define EMIT_ENUM(name, _type) name,
  FOR_EACH_PARSE_NODE_KIND(EMIT_ENUM)
#undef EMIT_ENUM
      Limit, /* domain size */
  BinOpFirst = ParseNodeKind::PipelineExpr,
  BinOpLast = ParseNodeKind::PowExpr,
  AssignmentStart = ParseNodeKind::AssignExpr,
  AssignmentLast = ParseNodeKind::PowAssignExpr,
};

inline bool IsDeleteKind(ParseNodeKind kind) {
  return ParseNodeKind::DeleteNameExpr <= kind &&
         kind <= ParseNodeKind::DeleteExpr;
}

inline bool IsTypeofKind(ParseNodeKind kind) {
  return ParseNodeKind::TypeOfNameExpr <= kind &&
         kind <= ParseNodeKind::TypeOfExpr;
}

/*
 * <Definitions>
 * Function (FunctionNode)
 *   funbox: ptr to js::FunctionBox holding function object containing arg and
 *           var properties.  We create the function object at parse (not emit)
 *           time to specialize arg and var bytecodes early.
 *   body: ParamsBody or null for lazily-parsed function, ordinarily;
 *         ParseNodeKind::LexicalScope for implicit function in genexpr
 *   syntaxKind: the syntax of the function
 * ParamsBody (ListNode)
 *   head: list of formal parameters with
 *           * Name node with non-empty name for SingleNameBinding without
 *             Initializer
 *           * AssignExpr node for SingleNameBinding with Initializer
 *           * Name node with empty name for destructuring
 *               expr: Array or Object for BindingPattern without
 *                     Initializer, Assign for BindingPattern with
 *                     Initializer
 *         followed by either:
 *           * StatementList node for function body statements
 *           * ReturnStmt for expression closure
 *   count: number of formal parameters + 1
 * Spread (UnaryNode)
 *   kid: expression being spread
 * ClassDecl (ClassNode)
 *   kid1: ClassNames for class name. can be null for anonymous class.
 *   kid2: expression after `extends`. null if no expression
 *   kid3: either of
 *           * ClassMemberList, if anonymous class
 *           * LexicalScopeNode which contains ClassMemberList as scopeBody,
 *             if named class
 * ClassNames (ClassNames)
 *   left: Name node for outer binding, or null if the class is an expression
 *         that doesn't create an outer binding
 *   right: Name node for inner binding
 * ClassMemberList (ListNode)
 *   head: list of N ClassMethod or ClassField nodes
 *   count: N >= 0
 * ClassMethod (ClassMethod)
 *   name: propertyName
 *   method: methodDefinition
 * Module (ModuleNode)
 *   body: statement list of the module
 *
 * <Statements>
 * StatementList (ListNode)
 *   head: list of N statements
 *   count: N >= 0
 * IfStmt (TernaryNode)
 *   kid1: cond
 *   kid2: then
 *   kid3: else or null
 * SwitchStmt (SwitchStatement)
 *   left: discriminant
 *   right: LexicalScope node that contains the list of Case nodes, with at
 *          most one default node.
 *   hasDefault: true if there's a default case
 * Case (CaseClause)
 *   left: case-expression if CaseClause, or null if DefaultClause
 *   right: StatementList node for this case's statements
 * WhileStmt (BinaryNode)
 *   left: cond
 *   right: body
 * DoWhileStmt (BinaryNode)
 *   left: body
 *   right: cond
 * ForStmt (ForNode)
 *   left: one of
 *           * ForIn: for (x in y) ...
 *           * ForOf: for (x of x) ...
 *           * ForHead: for (;;) ...
 *   right: body
 * ForIn (TernaryNode)
 *   kid1: declaration or expression to left of 'in'
 *   kid2: null
 *   kid3: object expr to right of 'in'
 * ForOf (TernaryNode)
 *   kid1: declaration or expression to left of 'of'
 *   kid2: null
 *   kid3: expr to right of 'of'
 * ForHead (TernaryNode)
 *   kid1:  init expr before first ';' or nullptr
 *   kid2:  cond expr before second ';' or nullptr
 *   kid3:  update expr after second ';' or nullptr
 * ThrowStmt (UnaryNode)
 *   kid: thrown exception
 * TryStmt (TernaryNode)
 *   kid1: try block
 *   kid2: null or LexicalScope for catch-block with scopeBody pointing to a
 *         Catch node
 *   kid3: null or finally block
 * Catch (BinaryNode)
 *   left: Name, Array, or Object catch var node
 *         (Array or Object if destructuring),
 *         or null if optional catch binding
 *   right: catch block statements
 * BreakStmt (BreakStatement)
 *   label: label or null
 * ContinueStmt (ContinueStatement)
 *   label: label or null
 * WithStmt (BinaryNode)
 *   left: head expr
 *   right: body
 * VarStmt, LetDecl, ConstDecl (ListNode)
 *   head: list of N Name or AssignExpr nodes
 *         each name node has either
 *           atom: variable name
 *           expr: initializer or null
 *         or
 *           atom: variable name
 *         each assignment node has
 *           left: pattern
 *           right: initializer
 *   count: N > 0
 * ReturnStmt (UnaryNode)
 *   kid: returned expression, or null if none
 * ExpressionStmt (UnaryNode)
 *   kid: expr
 *   prologue: true if Directive Prologue member in original source, not
 *             introduced via constant folding or other tree rewriting
 * EmptyStmt (NullaryNode)
 *   (no fields)
 * LabelStmt (LabeledStatement)
 *   atom: label
 *   expr: labeled statement
 * ImportDecl (BinaryNode)
 *   left: ImportSpecList import specifiers
 *   right: String module specifier
 * ImportSpecList (ListNode)
 *   head: list of N ImportSpec nodes
 *   count: N >= 0 (N = 0 for `import {} from ...`)
 * ImportSpec (BinaryNode)
 *   left: import name
 *   right: local binding name
 * ExportStmt (UnaryNode)
 *   kid: declaration expression
 * ExportFromStmt (BinaryNode)
 *   left: ExportSpecList export specifiers
 *   right: String module specifier
 * ExportSpecList (ListNode)
 *   head: list of N ExportSpec nodes
 *   count: N >= 0 (N = 0 for `export {}`)
 * ExportSpec (BinaryNode)
 *   left: local binding name
 *   right: export name
 * ExportDefaultStmt (BinaryNode)
 *   left: export default declaration or expression
 *   right: Name node for assignment
 *
 * <Expressions>
 * The `Expr` suffix is used for nodes that can appear anywhere an expression
 * could appear.  It is not used on a few weird kinds like Arguments and
 * CallSiteObj that are always the child node of an expression node, but which
 * can't stand alone.
 *
 * All left-associated binary trees of the same type are optimized into lists
 * to avoid recursion when processing expression chains.
 *
 * CommaExpr (ListNode)
 *   head: list of N comma-separated exprs
 *   count: N >= 2
 * AssignExpr (BinaryNode)
 *   left: target of assignment
 *   right: value to assign
 * AddAssignExpr, SubAssignExpr, BitOrAssignExpr, BitXorAssignExpr,
 * BitAndAssignExpr, LshAssignExpr, RshAssignExpr, UrshAssignExpr,
 * MulAssignExpr, DivAssignExpr, ModAssignExpr, PowAssignExpr (AssignmentNode)
 *   left: target of assignment
 *   right: value to assign
 * ConditionalExpr (ConditionalExpression)
 *   (cond ? thenExpr : elseExpr)
 *   kid1: cond
 *   kid2: thenExpr
 *   kid3: elseExpr
 * PipelineExpr, OrExpr, AndExpr, BitOrExpr, BitXorExpr, BitAndExpr,
 * StrictEqExpr, EqExpr, StrictNeExpr, NeExpr, LtExpr, LeExpr, GtExpr, GeExpr,
 * InstanceOfExpr, InExpr, LshExpr, RshExpr, UrshExpr, AddExpr, SubExpr,
 * MulExpr, DivExpr, ModExpr, PowExpr (ListNode)
 *   head: list of N subexpressions
 *         All of these operators are left-associative except Pow which is
 *         right-associative, but still forms a list (see comments in
 *         ParseNode::appendOrCreateList).
 *   count: N >= 2
 * PosExpr, NegExpr, VoidExpr, NotExpr, BitNotExpr, TypeOfNameExpr,
 * TypeOfExpr (UnaryNode)
 *   kid: unary expr
 * PreIncrementExpr, PostIncrementExpr, PreDecrementExpr,
 * PostDecrementExpr (UnaryNode)
 *   kid: member expr
 * NewExpr (BinaryNode)
 *   left: ctor expression on the left of the '('
 *   right: Arguments
 * DeleteNameExpr, DeletePropExpr, DeleteElemExpr, DeleteExpr (UnaryNode)
 *   kid: expression that's evaluated, then the overall delete evaluates to
 *        true; can't be a kind for a more-specific ParseNodeKind::Delete*
 *        unless constant folding (or a similar parse tree manipulation) has
 *        occurred
 *          * DeleteNameExpr: Name expr
 *          * DeletePropExpr: Dot expr
 *          * DeleteElemExpr: Elem expr
 *          * DeleteExpr: Member expr
 * PropertyNameExpr (NameNode)
 *   atom: property name being accessed
 * DotExpr (PropertyAccess)
 *   left: MEMBER expr to left of '.'
 *   right: PropertyName to right of '.'
 * ElemExpr (PropertyByValue)
 *   left: MEMBER expr to left of '['
 *   right: expr between '[' and ']'
 * CallExpr (BinaryNode)
 *   left: callee expression on the left of the '('
 *   right: Arguments
 * Arguments (ListNode)
 *   head: list of arg1, arg2, ... argN
 *   count: N >= 0
 * ArrayExpr (ListNode)
 *   head: list of N array element expressions
 *         holes ([,,]) are represented by Elision nodes,
 *         spread elements ([...X]) are represented by Spread nodes
 *   count: N >= 0
 * ObjectExpr (ListNode)
 *   head: list of N nodes, each item is one of:
 *           * MutateProto
 *           * PropertyDefinition
 *           * Shorthand
 *           * Spread
 *   count: N >= 0
 * PropertyDefinition (PropertyDefinition)
 *   key-value pair in object initializer or destructuring lhs
 *   left: property id
 *   right: value
 * Shorthand (BinaryNode)
 *   Same fields as PropertyDefinition. This is used for object literal
 *   properties using shorthand ({x}).
 * ComputedName (UnaryNode)
 *   ES6 ComputedPropertyName.
 *   kid: the AssignmentExpression inside the square brackets
 * Name (NameNode)
 *   atom: name, or object atom
 * StringExpr (NameNode)
 *   atom: string
 * TemplateStringListExpr (ListNode)
 *   head: list of alternating expr and template strings
 *           TemplateString [, expression, TemplateString]+
 *         there's at least one expression.  If the template literal contains
 *         no ${}-delimited expression, it's parsed as a single TemplateString
 * TemplateStringExpr (NameNode)
 *   atom: template string atom
 * TaggedTemplateExpr (BinaryNode)
 *   left: tag expression
 *   right: Arguments, with the first being the call site object, then
 *          arg1, arg2, ... argN
 * CallSiteObj (CallSiteNode)
 *   head:  an Array of raw TemplateString, then corresponding cooked
 *          TemplateString nodes
 *            Array [, cooked TemplateString]+
 *          where the Array is
 *            [raw TemplateString]+
 * RegExpExpr (RegExpLiteral)
 *   regexp: RegExp model object
 * NumberExpr (NumericLiteral)
 *   value: double value of numeric literal
 * BigIntExpr (BigIntLiteral)
 *   box: BigIntBox holding BigInt* value
 * TrueExpr, FalseExpr (BooleanLiteral)
 * NullExpr (NullLiteral)
 * RawUndefinedExpr (RawUndefinedLiteral)
 *
 * ThisExpr (UnaryNode)
 *   kid: '.this' Name if function `this`, else nullptr
 * SuperBase (UnaryNode)
 *   kid: '.this' Name
 * SuperCallExpr (BinaryNode)
 *   left: SuperBase
 *   right: Arguments
 * SetThis (BinaryNode)
 *   left: '.this' Name
 *   right: SuperCall
 *
 * LexicalScope (LexicalScopeNode)
 *   scopeBindings: scope bindings
 *   scopeBody: scope body
 * Generator (NullaryNode)
 * InitialYield (UnaryNode)
 *   kid: generator object
 * YieldExpr, YieldStarExpr, AwaitExpr (UnaryNode)
 *   kid: expr or null
 */

// FIXME: Remove `*Type` (bug 1489008)
#define FOR_EACH_PARSENODE_SUBCLASS(MACRO)                                   \
  MACRO(BinaryNode, BinaryNodeType, asBinary)                                \
  MACRO(AssignmentNode, AssignmentNodeType, asAssignment)                    \
  MACRO(CaseClause, CaseClauseType, asCaseClause)                            \
  MACRO(ClassMethod, ClassMethodType, asClassMethod)                         \
  MACRO(ClassField, ClassFieldType, asClassField)                            \
  MACRO(PropertyDefinition, PropertyDefinitionType, asPropertyDefinition)    \
  MACRO(ClassNames, ClassNamesType, asClassNames)                            \
  MACRO(ForNode, ForNodeType, asFor)                                         \
  MACRO(PropertyAccess, PropertyAccessType, asPropertyAccess)                \
  MACRO(PropertyByValue, PropertyByValueType, asPropertyByValue)             \
  MACRO(SwitchStatement, SwitchStatementType, asSwitchStatement)             \
                                                                             \
  MACRO(FunctionNode, FunctionNodeType, asFunction)                          \
  MACRO(ModuleNode, ModuleNodeType, asModule)                                \
                                                                             \
  MACRO(LexicalScopeNode, LexicalScopeNodeType, asLexicalScope)              \
                                                                             \
  MACRO(ListNode, ListNodeType, asList)                                      \
  MACRO(CallSiteNode, CallSiteNodeType, asCallSite)                          \
  MACRO(CallNode, CallNodeType, asCallNode)                                  \
                                                                             \
  MACRO(LoopControlStatement, LoopControlStatementType,                      \
        asLoopControlStatement)                                              \
  MACRO(BreakStatement, BreakStatementType, asBreakStatement)                \
  MACRO(ContinueStatement, ContinueStatementType, asContinueStatement)       \
                                                                             \
  MACRO(NameNode, NameNodeType, asName)                                      \
  MACRO(LabeledStatement, LabeledStatementType, asLabeledStatement)          \
                                                                             \
  MACRO(NullaryNode, NullaryNodeType, asNullary)                             \
  MACRO(BooleanLiteral, BooleanLiteralType, asBooleanLiteral)                \
  MACRO(DebuggerStatement, DebuggerStatementType, asDebuggerStatement)       \
  MACRO(NullLiteral, NullLiteralType, asNullLiteral)                         \
  MACRO(RawUndefinedLiteral, RawUndefinedLiteralType, asRawUndefinedLiteral) \
                                                                             \
  MACRO(NumericLiteral, NumericLiteralType, asNumericLiteral)                \
  MACRO(BigIntLiteral, BigIntLiteralType, asBigIntLiteral)                   \
                                                                             \
  MACRO(RegExpLiteral, RegExpLiteralType, asRegExpLiteral)                   \
                                                                             \
  MACRO(TernaryNode, TernaryNodeType, asTernary)                             \
  MACRO(ClassNode, ClassNodeType, asClass)                                   \
  MACRO(ConditionalExpression, ConditionalExpressionType,                    \
        asConditionalExpression)                                             \
  MACRO(TryNode, TryNodeType, asTry)                                         \
                                                                             \
  MACRO(UnaryNode, UnaryNodeType, asUnary)                                   \
  MACRO(ThisLiteral, ThisLiteralType, asThisLiteral)

#define DECLARE_CLASS(typeName, longTypeName, asMethodName) class typeName;
FOR_EACH_PARSENODE_SUBCLASS(DECLARE_CLASS)
#undef DECLARE_CLASS

enum class FunctionSyntaxKind {
  // A non-arrow function expression.
  Expression,

  // A named function appearing as a Statement.
  Statement,

  Arrow,
  Method,
  ClassConstructor,
  DerivedClassConstructor,
  Getter,
  Setter,
};

enum class AccessorType { None, Getter, Setter };

static inline bool IsConstructorKind(FunctionSyntaxKind kind) {
  return kind == FunctionSyntaxKind::ClassConstructor ||
         kind == FunctionSyntaxKind::DerivedClassConstructor;
}

static inline bool IsMethodDefinitionKind(FunctionSyntaxKind kind) {
  return IsConstructorKind(kind) || kind == FunctionSyntaxKind::Method ||
         kind == FunctionSyntaxKind::Getter ||
         kind == FunctionSyntaxKind::Setter;
}

class ParseNode {
  const ParseNodeKind pn_type; /* ParseNodeKind::PNK_* type */

  bool pn_parens : 1;       /* this expr was enclosed in parens */
  bool pn_rhs_anon_fun : 1; /* this expr is anonymous function or class that
                             * is a direct RHS of ParseNodeKind::Assign or
                             * ParseNodeKind::PropertyDefinition of property,
                             * that needs SetFunctionName. */

  ParseNode(const ParseNode& other) = delete;
  void operator=(const ParseNode& other) = delete;

 public:
  explicit ParseNode(ParseNodeKind kind)
      : pn_type(kind),
        pn_parens(false),
        pn_rhs_anon_fun(false),
        pn_pos(0, 0),
        pn_next(nullptr) {
    MOZ_ASSERT(kind < ParseNodeKind::Limit);
  }

  ParseNode(ParseNodeKind kind, const TokenPos& pos)
      : pn_type(kind),
        pn_parens(false),
        pn_rhs_anon_fun(false),
        pn_pos(pos),
        pn_next(nullptr) {
    MOZ_ASSERT(kind < ParseNodeKind::Limit);
  }

  ParseNodeKind getKind() const {
    MOZ_ASSERT(pn_type < ParseNodeKind::Limit);
    return pn_type;
  }
  bool isKind(ParseNodeKind kind) const { return getKind() == kind; }

 protected:
  // Used to implement test() on a few ParseNodes efficiently.
  // (This enum doesn't fully reflect the ParseNode class hierarchy,
  // so don't use it for anything else.)
  enum class TypeCode : uint8_t {
    Nullary,
    Unary,
    Binary,
    Ternary,
    List,
    Name,
    Other
  };

  // typeCodeTable[size_t(pnk)] is the type code of a ParseNode of kind pnk.
  static const TypeCode typeCodeTable[];

 public:
  TypeCode typeCode() const { return typeCodeTable[size_t(getKind())]; }

  bool isBinaryOperation() const {
    ParseNodeKind kind = getKind();
    return ParseNodeKind::BinOpFirst <= kind &&
           kind <= ParseNodeKind::BinOpLast;
  }
  inline bool isName(PropertyName* name) const;

  /* Boolean attributes. */
  bool isInParens() const { return pn_parens; }
  bool isLikelyIIFE() const { return isInParens(); }
  void setInParens(bool enabled) { pn_parens = enabled; }

  bool isDirectRHSAnonFunction() const { return pn_rhs_anon_fun; }
  void setDirectRHSAnonFunction(bool enabled) { pn_rhs_anon_fun = enabled; }

  TokenPos pn_pos;    /* two 16-bit pairs here, for 64 bits */
  ParseNode* pn_next; /* intrinsic link in parent PN_LIST */

 public:
  /*
   * If |left| is a list of the given kind/left-associative op, append
   * |right| to it and return |left|.  Otherwise return a [left, right] list.
   */
  static ParseNode* appendOrCreateList(ParseNodeKind kind, ParseNode* left,
                                       ParseNode* right,
                                       FullParseHandler* handler,
                                       ParseContext* pc);

  /* True if pn is a parsenode representing a literal constant. */
  bool isLiteral() const {
    return isKind(ParseNodeKind::NumberExpr) ||
           isKind(ParseNodeKind::BigIntExpr) ||
           isKind(ParseNodeKind::StringExpr) ||
           isKind(ParseNodeKind::TrueExpr) ||
           isKind(ParseNodeKind::FalseExpr) ||
           isKind(ParseNodeKind::NullExpr) ||
           isKind(ParseNodeKind::RawUndefinedExpr);
  }

  // True iff this is a for-in/of loop variable declaration (var/let/const).
  inline bool isForLoopDeclaration() const;

  enum AllowConstantObjects {
    DontAllowObjects = 0,
    AllowObjects,
    ForCopyOnWriteArray
  };

  MOZ_MUST_USE bool getConstantValue(JSContext* cx,
                                     AllowConstantObjects allowObjects,
                                     MutableHandleValue vp,
                                     Value* compare = nullptr,
                                     size_t ncompare = 0,
                                     NewObjectKind newKind = TenuredObject);
  inline bool isConstant();

  template <class NodeType>
  inline bool is() const {
    return NodeType::test(*this);
  }

  /* Casting operations. */
  template <class NodeType>
  inline NodeType& as() {
    MOZ_ASSERT(NodeType::test(*this));
    return *static_cast<NodeType*>(this);
  }

  template <class NodeType>
  inline const NodeType& as() const {
    MOZ_ASSERT(NodeType::test(*this));
    return *static_cast<const NodeType*>(this);
  }

#ifdef DEBUG
  // Debugger-friendly stderr printer.
  void dump();
  void dump(GenericPrinter& out);
  void dump(GenericPrinter& out, int indent);
#endif
};

// Remove a ParseNode, **pnp, from a parse tree, putting another ParseNode,
// *pn, in its place.
//
// pnp points to a ParseNode pointer. This must be the only pointer that points
// to the parse node being replaced. The replacement, *pn, is unchanged except
// for its pn_next pointer; updating that is necessary if *pn's new parent is a
// list node.
inline void ReplaceNode(ParseNode** pnp, ParseNode* pn) {
  pn->pn_next = (*pnp)->pn_next;
  *pnp = pn;
}

class NullaryNode : public ParseNode {
 public:
  NullaryNode(ParseNodeKind kind, const TokenPos& pos) : ParseNode(kind, pos) {
    MOZ_ASSERT(is<NullaryNode>());
  }

  static bool test(const ParseNode& node) {
    return node.typeCode() == TypeCode::Nullary;
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::Nullary; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    return true;
  }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif
};

class NameNode : public ParseNode {
  JSAtom* atom_; /* lexical name or label atom */

 public:
  NameNode(ParseNodeKind kind, JSAtom* atom, const TokenPos& pos)
      : ParseNode(kind, pos), atom_(atom) {
    MOZ_ASSERT(is<NameNode>());
  }

  static bool test(const ParseNode& node) {
    return node.typeCode() == TypeCode::Name;
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::Name; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    return true;
  }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif

  JSAtom* atom() const { return atom_; }

  PropertyName* name() const {
    MOZ_ASSERT(isKind(ParseNodeKind::Name));
    return atom()->asPropertyName();
  }

  void setAtom(JSAtom* atom) { atom_ = atom; }
};

inline bool ParseNode::isName(PropertyName* name) const {
  return getKind() == ParseNodeKind::Name && as<NameNode>().name() == name;
}

class UnaryNode : public ParseNode {
  ParseNode* kid_;
  bool prologue; /* directive prologue member */

 public:
  UnaryNode(ParseNodeKind kind, const TokenPos& pos, ParseNode* kid)
      : ParseNode(kind, pos), kid_(kid), prologue(false) {
    MOZ_ASSERT(is<UnaryNode>());
  }

  static bool test(const ParseNode& node) {
    return node.typeCode() == TypeCode::Unary;
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::Unary; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    if (kid_) {
      if (!visitor.visit(kid_)) {
        return false;
      }
    }
    return true;
  }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif

  ParseNode* kid() const { return kid_; }

  /* Return true if this node appears in a Directive Prologue. */
  bool isDirectivePrologueMember() const { return prologue; }

  void setIsDirectivePrologueMember() { prologue = true; }

  /*
   * Non-null if this is a statement node which could be a member of a
   * Directive Prologue: an expression statement consisting of a single
   * string literal.
   *
   * This considers only the node and its children, not its context. After
   * parsing, check the node's prologue flag to see if it is indeed part of
   * a directive prologue.
   *
   * Note that a Directive Prologue can contain statements that cannot
   * themselves be directives (string literals that include escape sequences
   * or escaped newlines, say). This member function returns true for such
   * nodes; we use it to determine the extent of the prologue.
   */
  JSAtom* isStringExprStatement() const {
    if (isKind(ParseNodeKind::ExpressionStmt)) {
      if (kid()->isKind(ParseNodeKind::StringExpr) && !kid()->isInParens()) {
        return kid()->as<NameNode>().atom();
      }
    }
    return nullptr;
  }

  // Methods used by FoldConstants.cpp.
  ParseNode** unsafeKidReference() { return &kid_; }
};

class BinaryNode : public ParseNode {
  ParseNode* left_;
  ParseNode* right_;

 public:
  BinaryNode(ParseNodeKind kind, const TokenPos& pos, ParseNode* left,
             ParseNode* right)
      : ParseNode(kind, pos), left_(left), right_(right) {
    MOZ_ASSERT(is<BinaryNode>());
  }

  BinaryNode(ParseNodeKind kind, ParseNode* left, ParseNode* right)
      : ParseNode(kind, TokenPos::box(left->pn_pos, right->pn_pos)),
        left_(left),
        right_(right) {
    MOZ_ASSERT(is<BinaryNode>());
  }

  static bool test(const ParseNode& node) {
    return node.typeCode() == TypeCode::Binary;
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::Binary; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    if (left_) {
      if (!visitor.visit(left_)) {
        return false;
      }
    }
    if (right_) {
      if (!visitor.visit(right_)) {
        return false;
      }
    }
    return true;
  }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif

  ParseNode* left() const { return left_; }

  ParseNode* right() const { return right_; }

  // Methods used by FoldConstants.cpp.
  // callers are responsible for keeping the list consistent.
  ParseNode** unsafeLeftReference() { return &left_; }

  ParseNode** unsafeRightReference() { return &right_; }
};

class AssignmentNode : public BinaryNode {
 public:
  AssignmentNode(ParseNodeKind kind, ParseNode* left, ParseNode* right)
      : BinaryNode(kind, TokenPos(left->pn_pos.begin, right->pn_pos.end), left,
                   right) {}

  static bool test(const ParseNode& node) {
    ParseNodeKind kind = node.getKind();
    bool match = ParseNodeKind::AssignmentStart <= kind &&
                 kind <= ParseNodeKind::AssignmentLast;
    MOZ_ASSERT_IF(match, node.is<BinaryNode>());
    return match;
  }
};

class ForNode : public BinaryNode {
  unsigned iflags_; /* JSITER_* flags */

 public:
  ForNode(const TokenPos& pos, ParseNode* forHead, ParseNode* body,
          unsigned iflags)
      : BinaryNode(ParseNodeKind::ForStmt, pos, forHead, body),
        iflags_(iflags) {
    MOZ_ASSERT(forHead->isKind(ParseNodeKind::ForIn) ||
               forHead->isKind(ParseNodeKind::ForOf) ||
               forHead->isKind(ParseNodeKind::ForHead));
  }

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::ForStmt);
    MOZ_ASSERT_IF(match, node.is<BinaryNode>());
    return match;
  }

  TernaryNode* head() const { return &left()->as<TernaryNode>(); }

  ParseNode* body() const { return right(); }

  unsigned iflags() const { return iflags_; }
};

class TernaryNode : public ParseNode {
  ParseNode* kid1_; /* condition, discriminant, etc. */
  ParseNode* kid2_; /* then-part, case list, etc. */
  ParseNode* kid3_; /* else-part, default case, etc. */

 public:
  TernaryNode(ParseNodeKind kind, ParseNode* kid1, ParseNode* kid2,
              ParseNode* kid3)
      : TernaryNode(kind, kid1, kid2, kid3,
                    TokenPos((kid1 ? kid1 : kid2 ? kid2 : kid3)->pn_pos.begin,
                             (kid3 ? kid3 : kid2 ? kid2 : kid1)->pn_pos.end)) {}

  TernaryNode(ParseNodeKind kind, ParseNode* kid1, ParseNode* kid2,
              ParseNode* kid3, const TokenPos& pos)
      : ParseNode(kind, pos), kid1_(kid1), kid2_(kid2), kid3_(kid3) {
    MOZ_ASSERT(is<TernaryNode>());
  }

  static bool test(const ParseNode& node) {
    return node.typeCode() == TypeCode::Ternary;
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::Ternary; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    if (kid1_) {
      if (!visitor.visit(kid1_)) {
        return false;
      }
    }
    if (kid2_) {
      if (!visitor.visit(kid2_)) {
        return false;
      }
    }
    if (kid3_) {
      if (!visitor.visit(kid3_)) {
        return false;
      }
    }
    return true;
  }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif

  ParseNode* kid1() const { return kid1_; }

  ParseNode* kid2() const { return kid2_; }

  ParseNode* kid3() const { return kid3_; }

  // Methods used by FoldConstants.cpp.
  ParseNode** unsafeKid1Reference() { return &kid1_; }

  ParseNode** unsafeKid2Reference() { return &kid2_; }

  ParseNode** unsafeKid3Reference() { return &kid3_; }
};

class ListNode : public ParseNode {
  ParseNode* head_;  /* first node in list */
  ParseNode** tail_; /* ptr to last node's pn_next in list */
  uint32_t count_;   /* number of nodes in list */
  uint32_t xflags;

 private:
  // xflags bits.

  // Statement list has top-level function statements.
  static constexpr uint32_t hasTopLevelFunctionDeclarationsBit = 0x01;

  // One or more of
  //   * array has holes
  //   * array has spread node
  static constexpr uint32_t hasArrayHoleOrSpreadBit = 0x02;

  // Array/Object/Class initializer has non-constants.
  //   * array has holes
  //   * array has spread node
  //   * array has element which is known not to be constant
  //   * array has no element
  //   * object/class has __proto__
  //   * object/class has property which is known not to be constant
  //   * object/class shorthand property
  //   * object/class spread property
  //   * object/class has method
  //   * object/class has computed property
  static constexpr uint32_t hasNonConstInitializerBit = 0x04;

  // Flag set by the emitter after emitting top-level function statements.
  static constexpr uint32_t emittedTopLevelFunctionDeclarationsBit = 0x08;

  void checkConsistency() const
#ifndef DEBUG
  {
  }
#endif
  ;

 public:
  ListNode(ParseNodeKind kind, const TokenPos& pos) : ParseNode(kind, pos) {
    makeEmpty();
    MOZ_ASSERT(is<ListNode>());
  }

  ListNode(ParseNodeKind kind, ParseNode* kid)
      : ParseNode(kind, kid->pn_pos),
        head_(kid),
        tail_(&kid->pn_next),
        count_(1),
        xflags(0) {
    if (kid->pn_pos.begin < pn_pos.begin) {
      pn_pos.begin = kid->pn_pos.begin;
    }
    pn_pos.end = kid->pn_pos.end;

    MOZ_ASSERT(is<ListNode>());
  }

  static bool test(const ParseNode& node) {
    return node.typeCode() == TypeCode::List;
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::List; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    ParseNode** listp = &head_;
    for (; *listp; listp = &(*listp)->pn_next) {
      // Don't use PN*& because we want to check if it changed, so we can use
      // ReplaceNode
      ParseNode* pn = *listp;
      if (!visitor.visit(pn)) {
        return false;
      }
      if (pn != *listp) {
        ReplaceNode(listp, pn);
      }
    }
    unsafeReplaceTail(listp);
    return true;
  }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif

  ParseNode* head() const { return head_; }

  ParseNode** tail() const { return tail_; }

  uint32_t count() const { return count_; }

  bool empty() const { return count() == 0; }

  MOZ_MUST_USE bool hasTopLevelFunctionDeclarations() const {
    MOZ_ASSERT(isKind(ParseNodeKind::StatementList));
    return xflags & hasTopLevelFunctionDeclarationsBit;
  }

  MOZ_MUST_USE bool emittedTopLevelFunctionDeclarations() const {
    MOZ_ASSERT(isKind(ParseNodeKind::StatementList));
    MOZ_ASSERT(hasTopLevelFunctionDeclarations());
    return xflags & emittedTopLevelFunctionDeclarationsBit;
  }

  MOZ_MUST_USE bool hasArrayHoleOrSpread() const {
    MOZ_ASSERT(isKind(ParseNodeKind::ArrayExpr));
    return xflags & hasArrayHoleOrSpreadBit;
  }

  MOZ_MUST_USE bool hasNonConstInitializer() const {
    MOZ_ASSERT(isKind(ParseNodeKind::ArrayExpr) ||
               isKind(ParseNodeKind::ObjectExpr));
    return xflags & hasNonConstInitializerBit;
  }

  void setHasTopLevelFunctionDeclarations() {
    MOZ_ASSERT(isKind(ParseNodeKind::StatementList));
    xflags |= hasTopLevelFunctionDeclarationsBit;
  }

  void setEmittedTopLevelFunctionDeclarations() {
    MOZ_ASSERT(isKind(ParseNodeKind::StatementList));
    MOZ_ASSERT(hasTopLevelFunctionDeclarations());
    xflags |= emittedTopLevelFunctionDeclarationsBit;
  }

  void setHasArrayHoleOrSpread() {
    MOZ_ASSERT(isKind(ParseNodeKind::ArrayExpr));
    xflags |= hasArrayHoleOrSpreadBit;
  }

  void setHasNonConstInitializer() {
    MOZ_ASSERT(isKind(ParseNodeKind::ArrayExpr) ||
               isKind(ParseNodeKind::ObjectExpr));
    xflags |= hasNonConstInitializerBit;
  }

  void unsetHasNonConstInitializer() {
    MOZ_ASSERT(isKind(ParseNodeKind::ArrayExpr) ||
               isKind(ParseNodeKind::ObjectExpr));
    xflags &= ~hasNonConstInitializerBit;
  }

  /*
   * Compute a pointer to the last element in a singly-linked list. NB: list
   * must be non-empty -- this is asserted!
   */
  ParseNode* last() const {
    MOZ_ASSERT(!empty());
    //
    // ParseNode                      ParseNode
    // +-----+---------+-----+        +-----+---------+-----+
    // | ... | pn_next | ... | +-...->| ... | pn_next | ... |
    // +-----+---------+-----+ |      +-----+---------+-----+
    // ^       |               |      ^     ^
    // |       +---------------+      |     |
    // |                              |     tail()
    // |                              |
    // head()                         last()
    //
    return (ParseNode*)(uintptr_t(tail()) - offsetof(ParseNode, pn_next));
  }

  void replaceLast(ParseNode* node) {
    MOZ_ASSERT(!empty());
    pn_pos.end = node->pn_pos.end;

    ParseNode* item = head();
    ParseNode* lastNode = last();
    MOZ_ASSERT(item);
    if (item == lastNode) {
      head_ = node;
    } else {
      while (item->pn_next != lastNode) {
        MOZ_ASSERT(item->pn_next);
        item = item->pn_next;
      }
      item->pn_next = node;
    }
    tail_ = &node->pn_next;
  }

  void makeEmpty() {
    head_ = nullptr;
    tail_ = &head_;
    count_ = 0;
    xflags = 0;
  }

  void append(ParseNode* item) {
    MOZ_ASSERT(item->pn_pos.begin >= pn_pos.begin);
    appendWithoutOrderAssumption(item);
  }

  void appendWithoutOrderAssumption(ParseNode* item) {
    pn_pos.end = item->pn_pos.end;
    *tail_ = item;
    tail_ = &item->pn_next;
    count_++;
  }

  void prepend(ParseNode* item) {
    item->pn_next = head_;
    head_ = item;
    if (tail_ == &head_) {
      tail_ = &item->pn_next;
    }
    count_++;
  }

  void prependAndUpdatePos(ParseNode* item) {
    prepend(item);
    pn_pos.begin = item->pn_pos.begin;
  }

  // Methods used by FoldConstants.cpp.
  // Caller is responsible for keeping the list consistent.
  ParseNode** unsafeHeadReference() { return &head_; }

  void unsafeReplaceTail(ParseNode** newTail) {
    tail_ = newTail;
    checkConsistency();
  }

  void unsafeDecrementCount() {
    MOZ_ASSERT(count() > 1);
    count_--;
  }

 private:
  // Classes to iterate over ListNode contents:
  //
  // Usage:
  //   ListNode* list;
  //   for (ParseNode* item : list->contents()) {
  //     // item is ParseNode* typed.
  //   }
  class iterator {
   private:
    ParseNode* node_;

    friend class ListNode;
    explicit iterator(ParseNode* node) : node_(node) {}

   public:
    bool operator==(const iterator& other) const {
      return node_ == other.node_;
    }

    bool operator!=(const iterator& other) const { return !(*this == other); }

    iterator& operator++() {
      node_ = node_->pn_next;
      return *this;
    }

    ParseNode* operator*() { return node_; }

    const ParseNode* operator*() const { return node_; }
  };

  class range {
   private:
    ParseNode* begin_;
    ParseNode* end_;

    friend class ListNode;
    range(ParseNode* begin, ParseNode* end) : begin_(begin), end_(end) {}

   public:
    iterator begin() { return iterator(begin_); }

    iterator end() { return iterator(end_); }

    const iterator begin() const { return iterator(begin_); }

    const iterator end() const { return iterator(end_); }

    const iterator cbegin() const { return begin(); }

    const iterator cend() const { return end(); }
  };

#ifdef DEBUG
  MOZ_MUST_USE bool contains(ParseNode* target) const {
    MOZ_ASSERT(target);
    for (ParseNode* node : contents()) {
      if (target == node) {
        return true;
      }
    }
    return false;
  }
#endif

 public:
  range contents() { return range(head(), nullptr); }

  const range contents() const { return range(head(), nullptr); }

  range contentsFrom(ParseNode* begin) {
    MOZ_ASSERT_IF(begin, contains(begin));
    return range(begin, nullptr);
  }

  const range contentsFrom(ParseNode* begin) const {
    MOZ_ASSERT_IF(begin, contains(begin));
    return range(begin, nullptr);
  }

  range contentsTo(ParseNode* end) {
    MOZ_ASSERT_IF(end, contains(end));
    return range(head(), end);
  }

  const range contentsTo(ParseNode* end) const {
    MOZ_ASSERT_IF(end, contains(end));
    return range(head(), end);
  }
};

inline bool ParseNode::isForLoopDeclaration() const {
  if (isKind(ParseNodeKind::VarStmt) || isKind(ParseNodeKind::LetDecl) ||
      isKind(ParseNodeKind::ConstDecl)) {
    MOZ_ASSERT(!as<ListNode>().empty());
    return true;
  }

  return false;
}

class FunctionNode : public ParseNode {
  FunctionBox* funbox_;
  ParseNode* body_;
  FunctionSyntaxKind syntaxKind_;

 public:
  FunctionNode(FunctionSyntaxKind syntaxKind, const TokenPos& pos)
      : ParseNode(ParseNodeKind::Function, pos),
        funbox_(nullptr),
        body_(nullptr),
        syntaxKind_(syntaxKind) {
    MOZ_ASSERT(!body_);
    MOZ_ASSERT(!funbox_);
    MOZ_ASSERT(is<FunctionNode>());
  }

  static bool test(const ParseNode& node) {
    return node.isKind(ParseNodeKind::Function);
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::Other; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    // Note: body is null for lazily-parsed functions.
    if (body_) {
      if (!visitor.visit(body_)) {
        return false;
      }
    }
    return true;
  }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif

  FunctionBox* funbox() const { return funbox_; }

  ListNode* body() const { return body_ ? &body_->as<ListNode>() : nullptr; }

  void setFunbox(FunctionBox* funbox) { funbox_ = funbox; }

  void setBody(ListNode* body) { body_ = body; }

  FunctionSyntaxKind syntaxKind() const { return syntaxKind_; }

  bool functionIsHoisted() const {
    return syntaxKind() == FunctionSyntaxKind::Statement;
  }
};

class ModuleNode : public ParseNode {
  ParseNode* body_;

 public:
  explicit ModuleNode(const TokenPos& pos)
      : ParseNode(ParseNodeKind::Module, pos), body_(nullptr) {
    MOZ_ASSERT(!body_);
    MOZ_ASSERT(is<ModuleNode>());
  }

  static bool test(const ParseNode& node) {
    return node.isKind(ParseNodeKind::Module);
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::Other; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    return visitor.visit(body_);
  }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif

  ListNode* body() const { return &body_->as<ListNode>(); }

  void setBody(ListNode* body) { body_ = body; }
};

class NumericLiteral : public ParseNode {
  double value_;              /* aligned numeric literal value */
  DecimalPoint decimalPoint_; /* Whether the number has a decimal point */

 public:
  NumericLiteral(double value, DecimalPoint decimalPoint, const TokenPos& pos)
      : ParseNode(ParseNodeKind::NumberExpr, pos),
        value_(value),
        decimalPoint_(decimalPoint) {}

  static bool test(const ParseNode& node) {
    return node.isKind(ParseNodeKind::NumberExpr);
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::Other; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    return true;
  }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif

  double value() const { return value_; }

  DecimalPoint decimalPoint() const { return decimalPoint_; }

  void setValue(double v) { value_ = v; }

  void setDecimalPoint(DecimalPoint d) { decimalPoint_ = d; }
};

class BigIntLiteral : public ParseNode {
  BigIntBox* box_;

 public:
  BigIntLiteral(BigIntBox* bibox, const TokenPos& pos)
      : ParseNode(ParseNodeKind::BigIntExpr, pos), box_(bibox) {}

  static bool test(const ParseNode& node) {
    return node.isKind(ParseNodeKind::BigIntExpr);
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::Other; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    return true;
  }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif

  BigIntBox* box() const { return box_; }
};

class LexicalScopeNode : public ParseNode {
  LexicalScope::Data* bindings;
  ParseNode* body;

 public:
  LexicalScopeNode(LexicalScope::Data* bindings, ParseNode* body)
      : ParseNode(ParseNodeKind::LexicalScope, body->pn_pos),
        bindings(bindings),
        body(body) {}

  static bool test(const ParseNode& node) {
    return node.isKind(ParseNodeKind::LexicalScope);
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::Other; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    return visitor.visit(body);
  }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif

  Handle<LexicalScope::Data*> scopeBindings() const {
    MOZ_ASSERT(!isEmptyScope());
    // Bindings' GC safety depend on the presence of an AutoKeepAtoms that
    // the rest of the frontend also depends on.
    return Handle<LexicalScope::Data*>::fromMarkedLocation(&bindings);
  }

  ParseNode* scopeBody() const { return body; }

  void setScopeBody(ParseNode* body) { this->body = body; }

  bool isEmptyScope() const { return !bindings; }
};

class LabeledStatement : public NameNode {
  ParseNode* statement_;

 public:
  LabeledStatement(PropertyName* label, ParseNode* stmt, uint32_t begin)
      : NameNode(ParseNodeKind::LabelStmt, label,
                 TokenPos(begin, stmt->pn_pos.end)),
        statement_(stmt) {}

  PropertyName* label() const { return atom()->asPropertyName(); }

  ParseNode* statement() const { return statement_; }

  static bool test(const ParseNode& node) {
    return node.isKind(ParseNodeKind::LabelStmt);
  }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    if (statement_) {
      if (!visitor.visit(statement_)) {
        return false;
      }
    }
    return true;
  }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif
};

// Inside a switch statement, a CaseClause is a case-label and the subsequent
// statements. The same node type is used for DefaultClauses. The only
// difference is that their caseExpression() is null.
class CaseClause : public BinaryNode {
 public:
  CaseClause(ParseNode* expr, ParseNode* stmts, uint32_t begin)
      : BinaryNode(ParseNodeKind::Case, TokenPos(begin, stmts->pn_pos.end),
                   expr, stmts) {}

  ParseNode* caseExpression() const { return left(); }

  bool isDefault() const { return !caseExpression(); }

  ListNode* statementList() const { return &right()->as<ListNode>(); }

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::Case);
    MOZ_ASSERT_IF(match, node.is<BinaryNode>());
    return match;
  }
};

class LoopControlStatement : public ParseNode {
  PropertyName* label_; /* target of break/continue statement */

 protected:
  LoopControlStatement(ParseNodeKind kind, PropertyName* label,
                       const TokenPos& pos)
      : ParseNode(kind, pos), label_(label) {
    MOZ_ASSERT(kind == ParseNodeKind::BreakStmt ||
               kind == ParseNodeKind::ContinueStmt);
    MOZ_ASSERT(is<LoopControlStatement>());
  }

 public:
  /* Label associated with this break/continue statement, if any. */
  PropertyName* label() const { return label_; }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif

  static bool test(const ParseNode& node) {
    return node.isKind(ParseNodeKind::BreakStmt) ||
           node.isKind(ParseNodeKind::ContinueStmt);
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::Other; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    return true;
  }
};

class BreakStatement : public LoopControlStatement {
 public:
  BreakStatement(PropertyName* label, const TokenPos& pos)
      : LoopControlStatement(ParseNodeKind::BreakStmt, label, pos) {}

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::BreakStmt);
    MOZ_ASSERT_IF(match, node.is<LoopControlStatement>());
    return match;
  }
};

class ContinueStatement : public LoopControlStatement {
 public:
  ContinueStatement(PropertyName* label, const TokenPos& pos)
      : LoopControlStatement(ParseNodeKind::ContinueStmt, label, pos) {}

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::ContinueStmt);
    MOZ_ASSERT_IF(match, node.is<LoopControlStatement>());
    return match;
  }
};

class DebuggerStatement : public NullaryNode {
 public:
  explicit DebuggerStatement(const TokenPos& pos)
      : NullaryNode(ParseNodeKind::DebuggerStmt, pos) {}

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::DebuggerStmt);
    MOZ_ASSERT_IF(match, node.is<NullaryNode>());
    return match;
  }
};

class ConditionalExpression : public TernaryNode {
 public:
  ConditionalExpression(ParseNode* condition, ParseNode* thenExpr,
                        ParseNode* elseExpr)
      : TernaryNode(ParseNodeKind::ConditionalExpr, condition, thenExpr,
                    elseExpr,
                    TokenPos(condition->pn_pos.begin, elseExpr->pn_pos.end)) {
    MOZ_ASSERT(condition);
    MOZ_ASSERT(thenExpr);
    MOZ_ASSERT(elseExpr);
  }

  ParseNode& condition() const { return *kid1(); }

  ParseNode& thenExpression() const { return *kid2(); }

  ParseNode& elseExpression() const { return *kid3(); }

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::ConditionalExpr);
    MOZ_ASSERT_IF(match, node.is<TernaryNode>());
    return match;
  }
};

class TryNode : public TernaryNode {
 public:
  TryNode(uint32_t begin, ParseNode* body, LexicalScopeNode* catchScope,
          ParseNode* finallyBlock)
      : TernaryNode(
            ParseNodeKind::TryStmt, body, catchScope, finallyBlock,
            TokenPos(begin,
                     (finallyBlock ? finallyBlock : catchScope)->pn_pos.end)) {
    MOZ_ASSERT(body);
    MOZ_ASSERT(catchScope || finallyBlock);
  }

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::TryStmt);
    MOZ_ASSERT_IF(match, node.is<TernaryNode>());
    return match;
  }

  ParseNode* body() const { return kid1(); }

  LexicalScopeNode* catchScope() const {
    return kid2() ? &kid2()->as<LexicalScopeNode>() : nullptr;
  }

  ParseNode* finallyBlock() const { return kid3(); }
};

class ThisLiteral : public UnaryNode {
 public:
  ThisLiteral(const TokenPos& pos, ParseNode* thisName)
      : UnaryNode(ParseNodeKind::ThisExpr, pos, thisName) {}

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::ThisExpr);
    MOZ_ASSERT_IF(match, node.is<UnaryNode>());
    return match;
  }
};

class NullLiteral : public NullaryNode {
 public:
  explicit NullLiteral(const TokenPos& pos)
      : NullaryNode(ParseNodeKind::NullExpr, pos) {}

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::NullExpr);
    MOZ_ASSERT_IF(match, node.is<NullaryNode>());
    return match;
  }
};

// This is only used internally, currently just for tagged templates and the
// initial value of fields without initializers. It represents the value
// 'undefined' (aka `void 0`), like NullLiteral represents the value 'null'.
class RawUndefinedLiteral : public NullaryNode {
 public:
  explicit RawUndefinedLiteral(const TokenPos& pos)
      : NullaryNode(ParseNodeKind::RawUndefinedExpr, pos) {}

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::RawUndefinedExpr);
    MOZ_ASSERT_IF(match, node.is<NullaryNode>());
    return match;
  }
};

class BooleanLiteral : public NullaryNode {
 public:
  BooleanLiteral(bool b, const TokenPos& pos)
      : NullaryNode(b ? ParseNodeKind::TrueExpr : ParseNodeKind::FalseExpr,
                    pos) {}

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::TrueExpr) ||
                 node.isKind(ParseNodeKind::FalseExpr);
    MOZ_ASSERT_IF(match, node.is<NullaryNode>());
    return match;
  }
};

class RegExpLiteral : public ParseNode {
  ObjectBox* objbox_;

 public:
  RegExpLiteral(ObjectBox* reobj, const TokenPos& pos)
      : ParseNode(ParseNodeKind::RegExpExpr, pos), objbox_(reobj) {}

  ObjectBox* objbox() const { return objbox_; }

#ifdef DEBUG
  void dumpImpl(GenericPrinter& out, int indent);
#endif

  static bool test(const ParseNode& node) {
    return node.isKind(ParseNodeKind::RegExpExpr);
  }

  static constexpr TypeCode classTypeCode() { return TypeCode::Other; }

  template <typename Visitor>
  bool accept(Visitor& visitor) {
    return true;
  }
};

class PropertyAccess : public BinaryNode {
 public:
  /*
   * PropertyAccess nodes can have any expression/'super' as left-hand
   * side, but the name must be a ParseNodeKind::PropertyName node.
   */
  PropertyAccess(ParseNode* lhs, NameNode* name, uint32_t begin, uint32_t end)
      : BinaryNode(ParseNodeKind::DotExpr, TokenPos(begin, end), lhs, name) {
    MOZ_ASSERT(lhs);
    MOZ_ASSERT(name);
  }

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::DotExpr);
    MOZ_ASSERT_IF(match, node.is<BinaryNode>());
    MOZ_ASSERT_IF(match, node.as<BinaryNode>().right()->isKind(
                             ParseNodeKind::PropertyNameExpr));
    return match;
  }

  ParseNode& expression() const { return *left(); }

  NameNode& key() const { return right()->as<NameNode>(); }

  // Method used by BytecodeEmitter::emitPropLHS for optimization.
  // Those methods allow expression to temporarily be nullptr for
  // optimization purpose.
  ParseNode* maybeExpression() const { return left(); }

  void setExpression(ParseNode* pn) { *unsafeLeftReference() = pn; }

  PropertyName& name() const {
    return *right()->as<NameNode>().atom()->asPropertyName();
  }

  bool isSuper() const {
    // ParseNodeKind::SuperBase cannot result from any expression syntax.
    return expression().isKind(ParseNodeKind::SuperBase);
  }
};

class PropertyByValue : public BinaryNode {
 public:
  PropertyByValue(ParseNode* lhs, ParseNode* propExpr, uint32_t begin,
                  uint32_t end)
      : BinaryNode(ParseNodeKind::ElemExpr, TokenPos(begin, end), lhs,
                   propExpr) {}

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::ElemExpr);
    MOZ_ASSERT_IF(match, node.is<BinaryNode>());
    return match;
  }

  ParseNode& expression() const { return *left(); }

  ParseNode& key() const { return *right(); }

  bool isSuper() const { return left()->isKind(ParseNodeKind::SuperBase); }
};

/*
 * A CallSiteNode represents the implicit call site object argument in a
 * TaggedTemplate.
 */
class CallSiteNode : public ListNode {
 public:
  explicit CallSiteNode(uint32_t begin)
      : ListNode(ParseNodeKind::CallSiteObj, TokenPos(begin, begin + 1)) {}

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::CallSiteObj);
    MOZ_ASSERT_IF(match, node.is<ListNode>());
    return match;
  }

  MOZ_MUST_USE bool getRawArrayValue(JSContext* cx, MutableHandleValue vp) {
    return head()->getConstantValue(cx, AllowObjects, vp);
  }

  ListNode* rawNodes() const {
    MOZ_ASSERT(head());
    return &head()->as<ListNode>();
  }
};

class CallNode : public BinaryNode {
  const JSOp callOp_;

 public:
  CallNode(ParseNodeKind kind, JSOp callOp, ParseNode* left, ParseNode* right)
      : CallNode(kind, callOp, TokenPos(left->pn_pos.begin, right->pn_pos.end),
                 left, right) {}

  CallNode(ParseNodeKind kind, JSOp callOp, TokenPos pos, ParseNode* left,
           ParseNode* right)
      : BinaryNode(kind, pos, left, right), callOp_(callOp) {
    MOZ_ASSERT(is<CallNode>());
  }

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::CallExpr) ||
                 node.isKind(ParseNodeKind::SuperCallExpr) ||
                 node.isKind(ParseNodeKind::TaggedTemplateExpr) ||
                 node.isKind(ParseNodeKind::CallImportExpr) ||
                 node.isKind(ParseNodeKind::NewExpr);
    MOZ_ASSERT_IF(match, node.is<BinaryNode>());
    return match;
  }

  JSOp callOp() { return callOp_; }
};

class ClassMethod : public BinaryNode {
  bool isStatic_;
  AccessorType accessorType_;

 public:
  /*
   * Method definitions often keep a name and function body that overlap,
   * so explicitly define the beginning and end here.
   */
  ClassMethod(ParseNode* name, ParseNode* body, AccessorType accessorType,
              bool isStatic)
      : BinaryNode(ParseNodeKind::ClassMethod,
                   TokenPos(name->pn_pos.begin, body->pn_pos.end), name, body),
        isStatic_(isStatic),
        accessorType_(accessorType) {}

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::ClassMethod);
    MOZ_ASSERT_IF(match, node.is<BinaryNode>());
    return match;
  }

  ParseNode& name() const { return *left(); }

  FunctionNode& method() const { return right()->as<FunctionNode>(); }

  bool isStatic() const { return isStatic_; }

  AccessorType accessorType() const { return accessorType_; }
};

class ClassField : public BinaryNode {
 public:
  ClassField(ParseNode* name, ParseNode* initializer)
      : BinaryNode(ParseNodeKind::ClassField,
                   initializer == nullptr
                       ? name->pn_pos
                       : TokenPos::box(name->pn_pos, initializer->pn_pos),
                   name, initializer) {}

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::ClassField);
    MOZ_ASSERT_IF(match, node.is<BinaryNode>());
    return match;
  }

  ParseNode& name() const { return *left(); }

  FunctionNode* initializer() const {
    return right() ? &right()->as<FunctionNode>() : nullptr;
  }
};

class PropertyDefinition : public BinaryNode {
  AccessorType accessorType_;

 public:
  PropertyDefinition(ParseNode* name, ParseNode* value,
                     AccessorType accessorType)
      : BinaryNode(ParseNodeKind::PropertyDefinition,
                   TokenPos(name->pn_pos.begin, value->pn_pos.end), name,
                   value),
        accessorType_(accessorType) {}

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::PropertyDefinition);
    MOZ_ASSERT_IF(match, node.is<BinaryNode>());
    return match;
  }

  AccessorType accessorType() { return accessorType_; }
};

class SwitchStatement : public BinaryNode {
  bool hasDefault_; /* only for ParseNodeKind::Switch */

 public:
  SwitchStatement(uint32_t begin, ParseNode* discriminant,
                  LexicalScopeNode* lexicalForCaseList, bool hasDefault)
      : BinaryNode(ParseNodeKind::SwitchStmt,
                   TokenPos(begin, lexicalForCaseList->pn_pos.end),
                   discriminant, lexicalForCaseList),
        hasDefault_(hasDefault) {
#ifdef DEBUG
    ListNode* cases = &lexicalForCaseList->scopeBody()->as<ListNode>();
    MOZ_ASSERT(cases->isKind(ParseNodeKind::StatementList));
    bool found = false;
    for (ParseNode* item : cases->contents()) {
      CaseClause* caseNode = &item->as<CaseClause>();
      if (caseNode->isDefault()) {
        found = true;
        break;
      }
    }
    MOZ_ASSERT(found == hasDefault);
#endif
  }

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::SwitchStmt);
    MOZ_ASSERT_IF(match, node.is<BinaryNode>());
    return match;
  }

  ParseNode& discriminant() const { return *left(); }

  LexicalScopeNode& lexicalForCaseList() const {
    return right()->as<LexicalScopeNode>();
  }

  bool hasDefault() const { return hasDefault_; }
};

class ClassNames : public BinaryNode {
 public:
  ClassNames(ParseNode* outerBinding, ParseNode* innerBinding,
             const TokenPos& pos)
      : BinaryNode(ParseNodeKind::ClassNames, pos, outerBinding, innerBinding) {
    MOZ_ASSERT_IF(outerBinding, outerBinding->isKind(ParseNodeKind::Name));
    MOZ_ASSERT(innerBinding->isKind(ParseNodeKind::Name));
    MOZ_ASSERT_IF(outerBinding, innerBinding->as<NameNode>().atom() ==
                                    outerBinding->as<NameNode>().atom());
  }

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::ClassNames);
    MOZ_ASSERT_IF(match, node.is<BinaryNode>());
    return match;
  }

  /*
   * Classes require two definitions: The first "outer" binding binds the
   * class into the scope in which it was declared. the outer binding is a
   * mutable lexial binding. The second "inner" binding binds the class by
   * name inside a block in which the methods are evaulated. It is immutable,
   * giving the methods access to the static members of the class even if
   * the outer binding has been overwritten.
   */
  NameNode* outerBinding() const {
    if (ParseNode* binding = left()) {
      return &binding->as<NameNode>();
    }
    return nullptr;
  }

  NameNode* innerBinding() const { return &right()->as<NameNode>(); }
};

class ClassNode : public TernaryNode {
 public:
  ClassNode(ParseNode* names, ParseNode* heritage,
            LexicalScopeNode* memberBlock, const TokenPos& pos)
      : TernaryNode(ParseNodeKind::ClassDecl, names, heritage, memberBlock,
                    pos) {
    MOZ_ASSERT_IF(names, names->is<ClassNames>());
  }

  static bool test(const ParseNode& node) {
    bool match = node.isKind(ParseNodeKind::ClassDecl);
    MOZ_ASSERT_IF(match, node.is<TernaryNode>());
    return match;
  }

  ClassNames* names() const {
    return kid1() ? &kid1()->as<ClassNames>() : nullptr;
  }
  ParseNode* heritage() const { return kid2(); }
  ListNode* memberList() const {
    ListNode* list =
        &kid3()->as<LexicalScopeNode>().scopeBody()->as<ListNode>();
    MOZ_ASSERT(list->isKind(ParseNodeKind::ClassMemberList));
    return list;
  }
  bool isEmptyScope() const {
    ParseNode* scope = kid3();
    return scope->as<LexicalScopeNode>().isEmptyScope();
  }
  Handle<LexicalScope::Data*> scopeBindings() const {
    ParseNode* scope = kid3();
    return scope->as<LexicalScopeNode>().scopeBindings();
  }
};

#ifdef DEBUG
void DumpParseTree(ParseNode* pn, GenericPrinter& out, int indent = 0);
#endif

class ParseNodeAllocator {
 public:
  explicit ParseNodeAllocator(JSContext* cx, LifoAlloc& alloc)
      : cx(cx), alloc(alloc) {}

  void* allocNode(size_t size);

 private:
  JSContext* cx;
  LifoAlloc& alloc;
};

inline bool ParseNode::isConstant() {
  switch (pn_type) {
    case ParseNodeKind::NumberExpr:
    case ParseNodeKind::StringExpr:
    case ParseNodeKind::TemplateStringExpr:
    case ParseNodeKind::NullExpr:
    case ParseNodeKind::RawUndefinedExpr:
    case ParseNodeKind::FalseExpr:
    case ParseNodeKind::TrueExpr:
      return true;
    case ParseNodeKind::ArrayExpr:
    case ParseNodeKind::ObjectExpr:
      return !as<ListNode>().hasNonConstInitializer();
    default:
      return false;
  }
}

class TraceListNode {
 protected:
  js::gc::Cell* gcThing;
  TraceListNode* traceLink;

  TraceListNode(js::gc::Cell* gcThing, TraceListNode* traceLink);

  bool isBigIntBox() const { return gcThing->is<BigInt>(); }
  bool isObjectBox() const { return gcThing->is<JSObject>(); }

  BigIntBox* asBigIntBox();
  ObjectBox* asObjectBox();

  virtual void trace(JSTracer* trc);

 public:
  static void TraceList(JSTracer* trc, TraceListNode* listHead);
};

class BigIntBox : public TraceListNode {
 public:
  BigIntBox(BigInt* bi, TraceListNode* link);
  BigInt* value() const { return gcThing->as<BigInt>(); }
};

class ObjectBox : public TraceListNode {
 protected:
  friend struct CGObjectList;
  ObjectBox* emitLink;

  ObjectBox(JSFunction* function, TraceListNode* link);

 public:
  ObjectBox(JSObject* obj, TraceListNode* link);

  JSObject* object() const { return gcThing->as<JSObject>(); }

  bool isFunctionBox() const { return object()->is<JSFunction>(); }
  FunctionBox* asFunctionBox();
};

enum ParseReportKind {
  ParseError,
  ParseWarning,
  ParseExtraWarning,
  ParseStrictError
};

static inline ParseNode* FunctionFormalParametersList(ParseNode* fn,
                                                      unsigned* numFormals) {
  MOZ_ASSERT(fn->isKind(ParseNodeKind::Function));
  ListNode* argsBody = fn->as<FunctionNode>().body();
  MOZ_ASSERT(argsBody->isKind(ParseNodeKind::ParamsBody));
  *numFormals = argsBody->count();
  if (*numFormals > 0 && argsBody->last()->is<LexicalScopeNode>() &&
      argsBody->last()->as<LexicalScopeNode>().scopeBody()->isKind(
          ParseNodeKind::StatementList)) {
    (*numFormals)--;
  }
  return argsBody->head();
}

bool IsAnonymousFunctionDefinition(ParseNode* pn);

} /* namespace frontend */
} /* namespace js */

#endif /* frontend_ParseNode_h */