1 /*
   2  * Copyright (c) 1999, 2025, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.tools.javac.tree;
  27 
  28 
  29 
  30 import com.sun.source.tree.Tree;
  31 import com.sun.source.util.TreePath;
  32 import com.sun.tools.javac.code.*;
  33 import com.sun.tools.javac.code.Symbol.RecordComponent;
  34 import com.sun.tools.javac.comp.AttrContext;
  35 import com.sun.tools.javac.comp.Env;
  36 import com.sun.tools.javac.tree.JCTree.*;
  37 import com.sun.tools.javac.tree.JCTree.JCPolyExpression.*;
  38 import com.sun.tools.javac.util.*;
  39 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
  40 
  41 import static com.sun.tools.javac.code.Flags.*;
  42 import static com.sun.tools.javac.code.Kinds.Kind.*;
  43 import com.sun.tools.javac.code.Symbol.VarSymbol;
  44 import static com.sun.tools.javac.code.TypeTag.BOOLEAN;
  45 import static com.sun.tools.javac.code.TypeTag.BOT;
  46 import static com.sun.tools.javac.tree.JCTree.Tag.*;
  47 import static com.sun.tools.javac.tree.JCTree.Tag.BLOCK;
  48 import static com.sun.tools.javac.tree.JCTree.Tag.SYNCHRONIZED;
  49 
  50 import javax.lang.model.element.ElementKind;
  51 import javax.tools.JavaFileObject;
  52 
  53 import java.util.function.Function;
  54 import java.util.function.Predicate;
  55 import java.util.function.ToIntFunction;
  56 
  57 import static com.sun.tools.javac.tree.JCTree.JCOperatorExpression.OperandPos.LEFT;
  58 import static com.sun.tools.javac.tree.JCTree.JCOperatorExpression.OperandPos.RIGHT;
  59 
  60 /** Utility class containing inspector methods for trees.
  61  *
  62  *  <p><b>This is NOT part of any supported API.
  63  *  If you write code that depends on this, you do so at your own risk.
  64  *  This code and its internal interfaces are subject to change or
  65  *  deletion without notice.</b>
  66  */
  67 public class TreeInfo {
  68 
  69     public static List<JCExpression> args(JCTree t) {
  70         switch (t.getTag()) {
  71             case APPLY:
  72                 return ((JCMethodInvocation)t).args;
  73             case NEWCLASS:
  74                 return ((JCNewClass)t).args;
  75             default:
  76                 return null;
  77         }
  78     }
  79 
  80     /** Is tree a constructor declaration?
  81      */
  82     public static boolean isConstructor(JCTree tree) {
  83         if (tree.hasTag(METHODDEF)) {
  84             Name name = ((JCMethodDecl) tree).name;
  85             return name == name.table.names.init;
  86         } else {
  87             return false;
  88         }
  89     }
  90 
  91     public static boolean isCanonicalConstructor(JCTree tree) {
  92         // the record flag is only set to the canonical constructor
  93         return isConstructor(tree) && (((JCMethodDecl)tree).sym.flags_field & RECORD) != 0;
  94     }
  95 
  96     public static boolean isCompactConstructor(JCTree tree) {
  97         // the record flag is only set to the canonical constructor
  98         return isCanonicalConstructor(tree) && (((JCMethodDecl)tree).sym.flags_field & COMPACT_RECORD_CONSTRUCTOR) != 0;
  99     }
 100 
 101     public static boolean isReceiverParam(JCTree tree) {
 102         if (tree.hasTag(VARDEF)) {
 103             return ((JCVariableDecl)tree).nameexpr != null;
 104         } else {
 105             return false;
 106         }
 107     }
 108 
 109     /** Is there a constructor declaration in the given list of trees?
 110      */
 111     public static boolean hasConstructors(List<JCTree> trees) {
 112         for (List<JCTree> l = trees; l.nonEmpty(); l = l.tail)
 113             if (isConstructor(l.head)) return true;
 114         return false;
 115     }
 116 
 117     public static boolean isMultiCatch(JCCatch catchClause) {
 118         return catchClause.param.vartype.hasTag(TYPEUNION);
 119     }
 120 
 121     /** Is statement an initializer for a synthetic field?
 122      */
 123     public static boolean isSyntheticInit(JCTree stat) {
 124         if (stat.hasTag(EXEC)) {
 125             JCExpressionStatement exec = (JCExpressionStatement)stat;
 126             if (exec.expr.hasTag(ASSIGN)) {
 127                 JCAssign assign = (JCAssign)exec.expr;
 128                 if (assign.lhs.hasTag(SELECT)) {
 129                     JCFieldAccess select = (JCFieldAccess)assign.lhs;
 130                     if (select.sym != null &&
 131                         (select.sym.flags() & SYNTHETIC) != 0) {
 132                         Name selected = name(select.selected);
 133                         if (selected != null && selected == selected.table.names._this)
 134                             return true;
 135                     }
 136                 }
 137             }
 138         }
 139         return false;
 140     }
 141 
 142     /** If the expression is a method call, return the method name, null
 143      *  otherwise. */
 144     public static Name calledMethodName(JCTree tree) {
 145         if (tree.hasTag(EXEC)) {
 146             JCExpressionStatement exec = (JCExpressionStatement)tree;
 147             if (exec.expr.hasTag(APPLY)) {
 148                 Name mname = TreeInfo.name(((JCMethodInvocation) exec.expr).meth);
 149                 return mname;
 150             }
 151         }
 152         return null;
 153     }
 154 
 155     /** Is this tree a 'this' identifier?
 156      */
 157     public static boolean isThisQualifier(JCTree tree) {
 158         switch (tree.getTag()) {
 159             case PARENS:
 160                 return isThisQualifier(skipParens(tree));
 161             case IDENT: {
 162                 JCIdent id = (JCIdent)tree;
 163                 return id.name == id.name.table.names._this;
 164             }
 165             default:
 166                 return false;
 167         }
 168     }
 169 
 170     /** Is this tree an identifier, possibly qualified by 'this'?
 171      */
 172     public static boolean isIdentOrThisDotIdent(JCTree tree) {
 173         switch (tree.getTag()) {
 174             case PARENS:
 175                 return isIdentOrThisDotIdent(skipParens(tree));
 176             case IDENT:
 177                 return true;
 178             case SELECT:
 179                 return isThisQualifier(((JCFieldAccess)tree).selected);
 180             default:
 181                 return false;
 182         }
 183     }
 184 
 185     /** Check if the given tree is an explicit reference to the 'this' instance of the
 186      *  class currently being compiled. This is true if tree is:
 187      *  - An unqualified 'this' identifier
 188      *  - A 'super' identifier qualified by a class name whose type is 'currentClass' or a supertype
 189      *  - A 'this' identifier qualified by a class name whose type is 'currentClass' or a supertype
 190      *    but also NOT an enclosing outer class of 'currentClass'.
 191      */
 192     public static boolean isExplicitThisReference(Types types, Type.ClassType currentClass, JCTree tree) {
 193         switch (tree.getTag()) {
 194             case PARENS:
 195                 return isExplicitThisReference(types, currentClass, skipParens(tree));
 196             case IDENT: {
 197                 JCIdent ident = (JCIdent)tree;
 198                 Names names = ident.name.table.names;
 199                 return ident.name == names._this || ident.name == names._super;
 200             }
 201             case SELECT: {
 202                 JCFieldAccess select = (JCFieldAccess)tree;
 203                 Type selectedType = types.erasure(select.selected.type);
 204                 if (!selectedType.hasTag(TypeTag.CLASS))
 205                     return false;
 206                 Symbol.ClassSymbol currentClassSym = (Symbol.ClassSymbol)((Type.ClassType)types.erasure(currentClass)).tsym;
 207                 Symbol.ClassSymbol selectedClassSym = (Symbol.ClassSymbol)((Type.ClassType)selectedType).tsym;
 208                 Names names = select.name.table.names;
 209                 return currentClassSym.isSubClass(selectedClassSym, types) &&
 210                         (select.name == names._super ||
 211                         (select.name == names._this &&
 212                             (currentClassSym == selectedClassSym ||
 213                             !currentClassSym.isEnclosedBy(selectedClassSym))));
 214             }
 215             default:
 216                 return false;
 217         }
 218     }
 219 
 220     /** Is this a call to super?
 221      */
 222     public static boolean isSuperCall(JCTree tree) {
 223         Name name = calledMethodName(tree);
 224         if (name != null) {
 225             Names names = name.table.names;
 226             return name==names._super;
 227         } else {
 228             return false;
 229         }
 230     }
 231 
 232     public static List<JCVariableDecl> recordFields(JCClassDecl tree) {
 233         return tree.defs.stream()
 234                 .filter(t -> t.hasTag(VARDEF))
 235                 .map(t -> (JCVariableDecl)t)
 236                 .filter(vd -> (vd.getModifiers().flags & (Flags.RECORD)) == RECORD)
 237                 .collect(List.collector());
 238     }
 239 
 240     public static List<Type> recordFieldTypes(JCClassDecl tree) {
 241         return recordFields(tree).stream()
 242                 .map(vd -> vd.type)
 243                 .collect(List.collector());
 244     }
 245 
 246     /** Is the given method a constructor containing a super() or this() call?
 247       */
 248     public static boolean hasAnyConstructorCall(JCMethodDecl tree) {
 249         return hasConstructorCall(tree, null);
 250     }
 251 
 252     /** Is the given method a constructor containing a super() and/or this() call?
 253       * The "target" is either names._this, names._super, or null for either/both.
 254       */
 255     public static boolean hasConstructorCall(JCMethodDecl tree, Name target) {
 256         JCMethodInvocation app = findConstructorCall(tree);
 257         return app != null && (target == null || target == name(app.meth));
 258     }
 259 
 260     /** Find the first super() or init() call in the given constructor.
 261      */
 262     public static JCMethodInvocation findConstructorCall(JCMethodDecl md) {
 263         if (!TreeInfo.isConstructor(md) || md.body == null)
 264             return null;
 265         return new ConstructorCallFinder(md.name.table.names).find(md).head;
 266     }
 267 
 268     /** Finds all calls to this() and/or super() in a given constructor.
 269      *  We can't assume they will be "top level" statements, because
 270      *  some synthetic calls to super() are added inside { } blocks.
 271      *  So we must recurse through the method's entire syntax tree.
 272      */
 273     private static class ConstructorCallFinder extends TreeScanner {
 274 
 275         final ListBuffer<JCMethodInvocation> calls = new ListBuffer<>();
 276         final Names names;
 277 
 278         ConstructorCallFinder(Names names) {
 279             this.names = names;
 280         }
 281 
 282         List<JCMethodInvocation> find(JCMethodDecl meth) {
 283             scan(meth);
 284             return calls.toList();
 285         }
 286 
 287         @Override
 288         public void visitApply(JCMethodInvocation invoke) {
 289             Name name = TreeInfo.name(invoke.meth);
 290             if ((name == names._this || name == names._super))
 291                 calls.append(invoke);
 292             super.visitApply(invoke);
 293         }
 294 
 295         @Override
 296         public void visitClassDef(JCClassDecl tree) {
 297             // don't descend any further
 298         }
 299 
 300         @Override
 301         public void visitLambda(JCLambda tree) {
 302             // don't descend any further
 303         }
 304     }
 305 
 306     /**
 307      * Is the given method invocation an invocation of this(...) or super(...)?
 308      */
 309     public static boolean isConstructorCall(JCMethodInvocation invoke) {
 310         Name name = TreeInfo.name(invoke.meth);
 311         Names names = name.table.names;
 312 
 313         return (name == names._this || name == names._super);
 314     }
 315 
 316     /** Finds super() invocations and translates them using the given mapping.
 317      */
 318     public static void mapSuperCalls(JCBlock block, Function<? super JCExpressionStatement, ? extends JCStatement> mapper) {
 319         block.stats = block.stats.map(new TreeInfo.SuperCallTranslator(mapper)::translate);
 320     }
 321 
 322     /** Finds all super() invocations and translates them somehow.
 323      */
 324     private static class SuperCallTranslator extends TreeTranslator {
 325 
 326         final Function<? super JCExpressionStatement, ? extends JCStatement> translator;
 327 
 328         /** Constructor.
 329          *
 330          * @param translator translates super() invocations, returning replacement statement or null for no change
 331          */
 332         SuperCallTranslator(Function<? super JCExpressionStatement, ? extends JCStatement> translator) {
 333             this.translator = translator;
 334         }
 335 
 336         // Because it returns void, anywhere super() can legally appear must be a location where a JCStatement
 337         // could also appear, so it's OK that we are replacing a JCExpressionStatement with a JCStatement here.
 338         @Override
 339         public void visitExec(JCExpressionStatement stat) {
 340             if (!TreeInfo.isSuperCall(stat) || (result = this.translator.apply(stat)) == null)
 341                 super.visitExec(stat);
 342         }
 343 
 344         @Override
 345         public void visitClassDef(JCClassDecl tree) {
 346             // don't descend any further
 347             result = tree;
 348         }
 349 
 350         @Override
 351         public void visitLambda(JCLambda tree) {
 352             // don't descend any further
 353             result = tree;
 354         }
 355     }
 356 
 357     /** Return true if a tree represents a diamond new expr. */
 358     public static boolean isDiamond(JCTree tree) {
 359         switch(tree.getTag()) {
 360             case TYPEAPPLY: return ((JCTypeApply)tree).getTypeArguments().isEmpty();
 361             case NEWCLASS: return isDiamond(((JCNewClass)tree).clazz);
 362             case ANNOTATED_TYPE: return isDiamond(((JCAnnotatedType)tree).underlyingType);
 363             default: return false;
 364         }
 365     }
 366 
 367     public static boolean isEnumInit(JCTree tree) {
 368         switch (tree.getTag()) {
 369             case VARDEF:
 370                 return (((JCVariableDecl)tree).mods.flags & ENUM) != 0;
 371             default:
 372                 return false;
 373         }
 374     }
 375 
 376     /** set 'polyKind' on given tree */
 377     public static void setPolyKind(JCTree tree, PolyKind pkind) {
 378         switch (tree.getTag()) {
 379             case APPLY:
 380                 ((JCMethodInvocation)tree).polyKind = pkind;
 381                 break;
 382             case NEWCLASS:
 383                 ((JCNewClass)tree).polyKind = pkind;
 384                 break;
 385             case REFERENCE:
 386                 ((JCMemberReference)tree).refPolyKind = pkind;
 387                 break;
 388             default:
 389                 throw new AssertionError("Unexpected tree: " + tree);
 390         }
 391     }
 392 
 393     /** set 'varargsElement' on given tree */
 394     public static void setVarargsElement(JCTree tree, Type varargsElement) {
 395         switch (tree.getTag()) {
 396             case APPLY:
 397                 ((JCMethodInvocation)tree).varargsElement = varargsElement;
 398                 break;
 399             case NEWCLASS:
 400                 ((JCNewClass)tree).varargsElement = varargsElement;
 401                 break;
 402             case REFERENCE:
 403                 ((JCMemberReference)tree).varargsElement = varargsElement;
 404                 break;
 405             default:
 406                 throw new AssertionError("Unexpected tree: " + tree);
 407         }
 408     }
 409 
 410     /** Return true if the tree corresponds to an expression statement */
 411     public static boolean isExpressionStatement(JCExpression tree) {
 412         switch(tree.getTag()) {
 413             case PREINC: case PREDEC:
 414             case POSTINC: case POSTDEC:
 415             case ASSIGN:
 416             case BITOR_ASG: case BITXOR_ASG: case BITAND_ASG:
 417             case SL_ASG: case SR_ASG: case USR_ASG:
 418             case PLUS_ASG: case MINUS_ASG:
 419             case MUL_ASG: case DIV_ASG: case MOD_ASG:
 420             case APPLY: case NEWCLASS:
 421             case ERRONEOUS:
 422                 return true;
 423             default:
 424                 return false;
 425         }
 426     }
 427 
 428     /** Return true if the tree corresponds to a statement */
 429     public static boolean isStatement(JCTree tree) {
 430         return (tree instanceof JCStatement) &&
 431                 !tree.hasTag(CLASSDEF) &&
 432                 !tree.hasTag(Tag.BLOCK) &&
 433                 !tree.hasTag(METHODDEF);
 434     }
 435 
 436     /**
 437      * Return true if the AST corresponds to a static select of the kind A.B
 438      */
 439     public static boolean isStaticSelector(JCTree base, Names names) {
 440         if (base == null)
 441             return false;
 442         switch (base.getTag()) {
 443             case IDENT:
 444                 JCIdent id = (JCIdent)base;
 445                 return id.name != names._this &&
 446                         id.name != names._super &&
 447                         isStaticSym(base);
 448             case SELECT:
 449                 return isStaticSym(base) &&
 450                     isStaticSelector(((JCFieldAccess)base).selected, names);
 451             case TYPEAPPLY:
 452             case TYPEARRAY:
 453                 return true;
 454             case ANNOTATED_TYPE:
 455                 return isStaticSelector(((JCAnnotatedType)base).underlyingType, names);
 456             default:
 457                 return false;
 458         }
 459     }
 460     //where
 461         private static boolean isStaticSym(JCTree tree) {
 462             Symbol sym = symbol(tree);
 463             return (sym.kind == TYP || sym.kind == PCK);
 464         }
 465 
 466     /** Return true if a tree represents the null literal. */
 467     public static boolean isNull(JCTree tree) {
 468         if (!tree.hasTag(LITERAL))
 469             return false;
 470         JCLiteral lit = (JCLiteral) tree;
 471         return (lit.typetag == BOT);
 472     }
 473 
 474     /** Return true iff this tree is a child of some annotation. */
 475     public static boolean isInAnnotation(Env<?> env, JCTree tree) {
 476         TreePath tp = TreePath.getPath(env.toplevel, tree);
 477         if (tp != null) {
 478             for (Tree t : tp) {
 479                 if (t.getKind() == Tree.Kind.ANNOTATION)
 480                     return true;
 481             }
 482         }
 483         return false;
 484     }
 485 
 486     public static String getCommentText(Env<?> env, JCTree tree) {
 487         DocCommentTable docComments = (tree.hasTag(JCTree.Tag.TOPLEVEL))
 488                 ? ((JCCompilationUnit) tree).docComments
 489                 : env.toplevel.docComments;
 490         return (docComments == null) ? null : docComments.getCommentText(tree);
 491     }
 492 
 493     /** The position of the first statement in a block, or the position of
 494      *  the block itself if it is empty.
 495      */
 496     public static int firstStatPos(JCTree tree) {
 497         if (tree.hasTag(BLOCK) && ((JCBlock) tree).stats.nonEmpty())
 498             return ((JCBlock) tree).stats.head.pos;
 499         else
 500             return tree.pos;
 501     }
 502 
 503     /** The closing brace position of given tree, if it is a block with
 504      *  defined bracePos.
 505      */
 506     public static int endPos(JCTree tree) {
 507         if (tree.hasTag(BLOCK) && ((JCBlock) tree).bracePos != Position.NOPOS)
 508             return ((JCBlock) tree).bracePos;
 509         else if (tree.hasTag(SYNCHRONIZED))
 510             return endPos(((JCSynchronized) tree).body);
 511         else if (tree.hasTag(TRY)) {
 512             JCTry t = (JCTry) tree;
 513             return endPos((t.finalizer != null) ? t.finalizer
 514                           : (t.catchers.nonEmpty() ? t.catchers.last().body : t.body));
 515         } else if (tree.hasTag(SWITCH) &&
 516                    ((JCSwitch) tree).bracePos != Position.NOPOS) {
 517             return ((JCSwitch) tree).bracePos;
 518         } else if (tree.hasTag(SWITCH_EXPRESSION) &&
 519                    ((JCSwitchExpression) tree).bracePos != Position.NOPOS) {
 520             return ((JCSwitchExpression) tree).bracePos;
 521         } else
 522             return tree.pos;
 523     }
 524 
 525 
 526     /** Get the start position for a tree node.  The start position is
 527      * defined to be the position of the first character of the first
 528      * token of the node's source text.
 529      * @param tree  The tree node
 530      */
 531     public static int getStartPos(JCTree tree) {
 532         if (tree == null)
 533             return Position.NOPOS;
 534 
 535         switch(tree.getTag()) {
 536             case MODULEDEF: {
 537                 JCModuleDecl md = (JCModuleDecl)tree;
 538                 return md.mods.annotations.isEmpty() ? md.pos :
 539                        md.mods.annotations.head.pos;
 540             }
 541             case PACKAGEDEF: {
 542                 JCPackageDecl pd = (JCPackageDecl)tree;
 543                 return pd.annotations.isEmpty() ? pd.pos :
 544                        pd.annotations.head.pos;
 545             }
 546             case APPLY:
 547                 return getStartPos(((JCMethodInvocation) tree).meth);
 548             case ASSIGN:
 549                 return getStartPos(((JCAssign) tree).lhs);
 550             case BITOR_ASG: case BITXOR_ASG: case BITAND_ASG:
 551             case SL_ASG: case SR_ASG: case USR_ASG:
 552             case PLUS_ASG: case MINUS_ASG: case MUL_ASG:
 553             case DIV_ASG: case MOD_ASG:
 554             case OR: case AND: case BITOR:
 555             case BITXOR: case BITAND: case EQ:
 556             case NE: case LT: case GT:
 557             case LE: case GE: case SL:
 558             case SR: case USR: case PLUS:
 559             case MINUS: case MUL: case DIV:
 560             case MOD:
 561             case POSTINC:
 562             case POSTDEC:
 563                 return getStartPos(((JCOperatorExpression) tree).getOperand(LEFT));
 564             case CLASSDEF: {
 565                 JCClassDecl node = (JCClassDecl)tree;
 566                 if (node.mods.pos != Position.NOPOS)
 567                     return node.mods.pos;
 568                 break;
 569             }
 570             case CONDEXPR:
 571                 return getStartPos(((JCConditional) tree).cond);
 572             case EXEC:
 573                 return getStartPos(((JCExpressionStatement) tree).expr);
 574             case INDEXED:
 575                 return getStartPos(((JCArrayAccess) tree).indexed);
 576             case METHODDEF: {
 577                 JCMethodDecl node = (JCMethodDecl)tree;
 578                 if (node.mods.pos != Position.NOPOS)
 579                     return node.mods.pos;
 580                 if (node.typarams.nonEmpty()) // List.nil() used for no typarams
 581                     return getStartPos(node.typarams.head);
 582                 return node.restype == null ? node.pos : getStartPos(node.restype);
 583             }
 584             case SELECT:
 585                 return getStartPos(((JCFieldAccess) tree).selected);
 586             case TYPEAPPLY:
 587                 return getStartPos(((JCTypeApply) tree).clazz);
 588             case TYPEARRAY:
 589                 return getStartPos(((JCArrayTypeTree) tree).elemtype);
 590             case TYPETEST:
 591                 return getStartPos(((JCInstanceOf) tree).expr);
 592             case ANNOTATED_TYPE: {
 593                 JCAnnotatedType node = (JCAnnotatedType) tree;
 594                 if (node.annotations.nonEmpty()) {
 595                     if (node.underlyingType.hasTag(TYPEARRAY) ||
 596                             node.underlyingType.hasTag(SELECT)) {
 597                         return getStartPos(node.underlyingType);
 598                     } else {
 599                         return getStartPos(node.annotations.head);
 600                     }
 601                 } else {
 602                     return getStartPos(node.underlyingType);
 603                 }
 604             }
 605             case NEWCLASS: {
 606                 JCNewClass node = (JCNewClass)tree;
 607                 if (node.encl != null)
 608                     return getStartPos(node.encl);
 609                 break;
 610             }
 611             case VARDEF: {
 612                 JCVariableDecl node = (JCVariableDecl)tree;
 613                 if (node.mods.pos != Position.NOPOS) {
 614                     return node.mods.pos;
 615                 } else if (node.vartype != null) {
 616                     return getStartPos(node.vartype);
 617                 } else if (node.typePos != Position.NOPOS) {
 618                     return node.typePos;
 619                 }
 620                 break;
 621             }
 622             case BINDINGPATTERN: {
 623                 JCBindingPattern node = (JCBindingPattern)tree;
 624                 return getStartPos(node.var);
 625             }
 626             case ERRONEOUS: {
 627                 JCErroneous node = (JCErroneous)tree;
 628                 if (node.errs != null && node.errs.nonEmpty()) {
 629                     int pos = getStartPos(node.errs.head);
 630                     if (pos != Position.NOPOS) {
 631                         return pos;
 632                     }
 633                 }
 634                 break;
 635             }
 636         }
 637         return tree.pos;
 638     }
 639 
 640     /** The end position of given tree, given  a table of end positions generated by the parser
 641      */
 642     public static int getEndPos(JCTree tree, EndPosTable endPosTable) {
 643         if (tree == null)
 644             return Position.NOPOS;
 645 
 646         int mapPos = endPosTable.getEndPos(tree);
 647         if (mapPos != Position.NOPOS)
 648             return mapPos;
 649 
 650         switch(tree.getTag()) {
 651             case BITOR_ASG: case BITXOR_ASG: case BITAND_ASG:
 652             case SL_ASG: case SR_ASG: case USR_ASG:
 653             case PLUS_ASG: case MINUS_ASG: case MUL_ASG:
 654             case DIV_ASG: case MOD_ASG:
 655             case OR: case AND: case BITOR:
 656             case BITXOR: case BITAND: case EQ:
 657             case NE: case LT: case GT:
 658             case LE: case GE: case SL:
 659             case SR: case USR: case PLUS:
 660             case MINUS: case MUL: case DIV:
 661             case MOD:
 662             case POS:
 663             case NEG:
 664             case NOT:
 665             case COMPL:
 666             case PREINC:
 667             case PREDEC:
 668                 return getEndPos(((JCOperatorExpression) tree).getOperand(RIGHT), endPosTable);
 669             case CASE:
 670                 return getEndPos(((JCCase) tree).stats.last(), endPosTable);
 671             case CATCH:
 672                 return getEndPos(((JCCatch) tree).body, endPosTable);
 673             case CONDEXPR:
 674                 return getEndPos(((JCConditional) tree).falsepart, endPosTable);
 675             case FORLOOP:
 676                 return getEndPos(((JCForLoop) tree).body, endPosTable);
 677             case FOREACHLOOP:
 678                 return getEndPos(((JCEnhancedForLoop) tree).body, endPosTable);
 679             case IF: {
 680                 JCIf node = (JCIf)tree;
 681                 if (node.elsepart == null) {
 682                     return getEndPos(node.thenpart, endPosTable);
 683                 } else {
 684                     return getEndPos(node.elsepart, endPosTable);
 685                 }
 686             }
 687             case LABELLED:
 688                 return getEndPos(((JCLabeledStatement) tree).body, endPosTable);
 689             case MODIFIERS:
 690                 return getEndPos(((JCModifiers) tree).annotations.last(), endPosTable);
 691             case SYNCHRONIZED:
 692                 return getEndPos(((JCSynchronized) tree).body, endPosTable);
 693             case TOPLEVEL:
 694                 return getEndPos(((JCCompilationUnit) tree).defs.last(), endPosTable);
 695             case TRY: {
 696                 JCTry node = (JCTry)tree;
 697                 if (node.finalizer != null) {
 698                     return getEndPos(node.finalizer, endPosTable);
 699                 } else if (!node.catchers.isEmpty()) {
 700                     return getEndPos(node.catchers.last(), endPosTable);
 701                 } else {
 702                     return getEndPos(node.body, endPosTable);
 703                 }
 704             }
 705             case WILDCARD:
 706                 return getEndPos(((JCWildcard) tree).inner, endPosTable);
 707             case TYPECAST:
 708                 return getEndPos(((JCTypeCast) tree).expr, endPosTable);
 709             case TYPETEST:
 710                 return getEndPos(((JCInstanceOf) tree).pattern, endPosTable);
 711             case WHILELOOP:
 712                 return getEndPos(((JCWhileLoop) tree).body, endPosTable);
 713             case ANNOTATED_TYPE:
 714                 return getEndPos(((JCAnnotatedType) tree).underlyingType, endPosTable);
 715             case ERRONEOUS: {
 716                 JCErroneous node = (JCErroneous)tree;
 717                 if (node.errs != null && node.errs.nonEmpty())
 718                     return getEndPos(node.errs.last(), endPosTable);
 719             }
 720         }
 721         return Position.NOPOS;
 722     }
 723 
 724 
 725     /** A DiagnosticPosition with the preferred position set to the
 726      *  closing brace position of given tree, if it is a block with
 727      *  defined closing brace position.
 728      */
 729     public static DiagnosticPosition diagEndPos(final JCTree tree) {
 730         final int endPos = TreeInfo.endPos(tree);
 731         return new DiagnosticPosition() {
 732             public JCTree getTree() { return tree; }
 733             public int getStartPosition() { return TreeInfo.getStartPos(tree); }
 734             public int getPreferredPosition() { return endPos; }
 735             public int getEndPosition(EndPosTable endPosTable) {
 736                 return TreeInfo.getEndPos(tree, endPosTable);
 737             }
 738         };
 739     }
 740 
 741     public enum PosKind {
 742         START_POS(TreeInfo::getStartPos),
 743         FIRST_STAT_POS(TreeInfo::firstStatPos),
 744         END_POS(TreeInfo::endPos);
 745 
 746         final ToIntFunction<JCTree> posFunc;
 747 
 748         PosKind(ToIntFunction<JCTree> posFunc) {
 749             this.posFunc = posFunc;
 750         }
 751 
 752         int toPos(JCTree tree) {
 753             return posFunc.applyAsInt(tree);
 754         }
 755     }
 756 
 757     /** The position of the finalizer of given try/synchronized statement.
 758      */
 759     public static int finalizerPos(JCTree tree, PosKind posKind) {
 760         if (tree.hasTag(TRY)) {
 761             JCTry t = (JCTry) tree;
 762             Assert.checkNonNull(t.finalizer);
 763             return posKind.toPos(t.finalizer);
 764         } else if (tree.hasTag(SYNCHRONIZED)) {
 765             return endPos(((JCSynchronized) tree).body);
 766         } else {
 767             throw new AssertionError();
 768         }
 769     }
 770 
 771     /** Find the position for reporting an error about a symbol, where
 772      *  that symbol is defined somewhere in the given tree. */
 773     public static int positionFor(final Symbol sym, final JCTree tree) {
 774         JCTree decl = declarationFor(sym, tree);
 775         return ((decl != null) ? decl : tree).pos;
 776     }
 777 
 778     /** Find the position for reporting an error about a symbol, where
 779      *  that symbol is defined somewhere in the given tree. */
 780     public static DiagnosticPosition diagnosticPositionFor(final Symbol sym, final JCTree tree) {
 781         return diagnosticPositionFor(sym, tree, false);
 782     }
 783 
 784     public static DiagnosticPosition diagnosticPositionFor(final Symbol sym, final JCTree tree, boolean returnNullIfNotFound) {
 785         return diagnosticPositionFor(sym, tree, returnNullIfNotFound, null);
 786     }
 787 
 788     public static DiagnosticPosition diagnosticPositionFor(final Symbol sym, final JCTree tree, boolean returnNullIfNotFound,
 789             Predicate<? super JCTree> filter) {
 790         class DiagScanner extends DeclScanner {
 791             DiagScanner(Symbol sym, Predicate<? super JCTree> filter) {
 792                 super(sym, filter);
 793             }
 794 
 795             public void visitIdent(JCIdent that) {
 796                 if (!checkMatch(that, that.sym))
 797                     super.visitIdent(that);
 798             }
 799             public void visitSelect(JCFieldAccess that) {
 800                 if (!checkMatch(that, that.sym))
 801                     super.visitSelect(that);
 802             }
 803         }
 804         DiagScanner s = new DiagScanner(sym, filter);
 805         tree.accept(s);
 806         JCTree decl = s.result;
 807         if (decl == null && returnNullIfNotFound) { return null; }
 808         return ((decl != null) ? decl : tree).pos();
 809     }
 810 
 811     public static DiagnosticPosition diagnosticPositionFor(final Symbol sym, final List<? extends JCTree> trees) {
 812         return trees.stream().map(t -> TreeInfo.diagnosticPositionFor(sym, t)).filter(t -> t != null).findFirst().get();
 813     }
 814 
 815     private static class DeclScanner extends TreeScanner {
 816         final Symbol sym;
 817         final Predicate<? super JCTree> filter;
 818 
 819         DeclScanner(final Symbol sym) {
 820             this(sym, null);
 821         }
 822         DeclScanner(final Symbol sym, Predicate<? super JCTree> filter) {
 823             this.sym = sym;
 824             this.filter = filter;
 825         }
 826 
 827         JCTree result = null;
 828         public void scan(JCTree tree) {
 829             if (tree!=null && result==null)
 830                 tree.accept(this);
 831         }
 832         public void visitTopLevel(JCCompilationUnit that) {
 833             if (!checkMatch(that, that.packge))
 834                 super.visitTopLevel(that);
 835         }
 836         public void visitModuleDef(JCModuleDecl that) {
 837             checkMatch(that, that.sym);
 838             // no need to scan within module declaration
 839         }
 840         public void visitPackageDef(JCPackageDecl that) {
 841             if (!checkMatch(that, that.packge))
 842                 super.visitPackageDef(that);
 843         }
 844         public void visitClassDef(JCClassDecl that) {
 845             if (!checkMatch(that, that.sym))
 846                 super.visitClassDef(that);
 847         }
 848         public void visitMethodDef(JCMethodDecl that) {
 849             if (!checkMatch(that, that.sym))
 850                 super.visitMethodDef(that);
 851         }
 852         public void visitVarDef(JCVariableDecl that) {
 853             if (!checkMatch(that, that.sym))
 854                 super.visitVarDef(that);
 855         }
 856         public void visitTypeParameter(JCTypeParameter that) {
 857             if (that.type == null || !checkMatch(that, that.type.tsym))
 858                 super.visitTypeParameter(that);
 859         }
 860 
 861         protected boolean checkMatch(JCTree that, Symbol thatSym) {
 862             if (thatSym == this.sym && (filter == null || filter.test(that))) {
 863                 result = that;
 864                 return true;
 865             }
 866             if (this.sym.getKind() == ElementKind.RECORD_COMPONENT) {
 867                 if (thatSym != null && thatSym.getKind() == ElementKind.FIELD && (thatSym.flags_field & RECORD) != 0) {
 868                     RecordComponent rc = thatSym.enclClass().getRecordComponent((VarSymbol)thatSym);
 869                     return checkMatch(rc.declarationFor(), rc);
 870                 }
 871             }
 872             return false;
 873         }
 874     }
 875 
 876     /** Find the declaration for a symbol, where
 877      *  that symbol is defined somewhere in the given tree. */
 878     public static JCTree declarationFor(final Symbol sym, final JCTree tree) {
 879         DeclScanner s = new DeclScanner(sym);
 880         tree.accept(s);
 881         return s.result;
 882     }
 883 
 884     /** Return the statement referenced by a label.
 885      *  If the label refers to a loop or switch, return that switch
 886      *  otherwise return the labelled statement itself
 887      */
 888     public static JCTree referencedStatement(JCLabeledStatement tree) {
 889         JCTree t = tree;
 890         do t = ((JCLabeledStatement) t).body;
 891         while (t.hasTag(LABELLED));
 892         switch (t.getTag()) {
 893         case DOLOOP: case WHILELOOP: case FORLOOP: case FOREACHLOOP: case SWITCH:
 894             return t;
 895         default:
 896             return tree;
 897         }
 898     }
 899 
 900     /** Skip parens and return the enclosed expression
 901      */
 902     public static JCExpression skipParens(JCExpression tree) {
 903         while (tree.hasTag(PARENS)) {
 904             tree = ((JCParens) tree).expr;
 905         }
 906         return tree;
 907     }
 908 
 909     /** Skip parens and return the enclosed expression
 910      */
 911     public static JCTree skipParens(JCTree tree) {
 912         if (tree.hasTag(PARENS))
 913             return skipParens((JCParens)tree);
 914         else
 915             return tree;
 916     }
 917 
 918     /** Return the types of a list of trees.
 919      */
 920     public static List<Type> types(List<? extends JCTree> trees) {
 921         ListBuffer<Type> ts = new ListBuffer<>();
 922         for (List<? extends JCTree> l = trees; l.nonEmpty(); l = l.tail)
 923             ts.append(l.head.type);
 924         return ts.toList();
 925     }
 926 
 927     /** If this tree is an identifier or a field or a parameterized type,
 928      *  return its name, otherwise return null.
 929      */
 930     public static Name name(JCTree tree) {
 931         switch (tree.getTag()) {
 932         case IDENT:
 933             return ((JCIdent) tree).name;
 934         case SELECT:
 935             return ((JCFieldAccess) tree).name;
 936         case TYPEAPPLY:
 937             return name(((JCTypeApply) tree).clazz);
 938         default:
 939             return null;
 940         }
 941     }
 942 
 943     /** If this tree is a qualified identifier, its return fully qualified name,
 944      *  otherwise return null.
 945      */
 946     public static Name fullName(JCTree tree) {
 947         tree = skipParens(tree);
 948         switch (tree.getTag()) {
 949         case IDENT:
 950             return ((JCIdent) tree).name;
 951         case SELECT:
 952             Name sname = fullName(((JCFieldAccess) tree).selected);
 953             return sname == null ? null : sname.append('.', name(tree));
 954         default:
 955             return null;
 956         }
 957     }
 958 
 959     public static Symbol symbolFor(JCTree node) {
 960         Symbol sym = symbolForImpl(node);
 961 
 962         return sym != null ? sym.baseSymbol() : null;
 963     }
 964 
 965     private static Symbol symbolForImpl(JCTree node) {
 966         node = skipParens(node);
 967         switch (node.getTag()) {
 968         case TOPLEVEL:
 969             JCCompilationUnit cut = (JCCompilationUnit) node;
 970             JCModuleDecl moduleDecl = cut.getModuleDecl();
 971             if (isModuleInfo(cut) && moduleDecl != null)
 972                 return symbolFor(moduleDecl);
 973             return cut.packge;
 974         case MODULEDEF:
 975             return ((JCModuleDecl) node).sym;
 976         case PACKAGEDEF:
 977             return ((JCPackageDecl) node).packge;
 978         case CLASSDEF:
 979             return ((JCClassDecl) node).sym;
 980         case METHODDEF:
 981             return ((JCMethodDecl) node).sym;
 982         case VARDEF:
 983             return ((JCVariableDecl) node).sym;
 984         case IDENT:
 985             return ((JCIdent) node).sym;
 986         case SELECT:
 987             return ((JCFieldAccess) node).sym;
 988         case REFERENCE:
 989             return ((JCMemberReference) node).sym;
 990         case NEWCLASS:
 991             return ((JCNewClass) node).constructor;
 992         case APPLY:
 993             return symbolFor(((JCMethodInvocation) node).meth);
 994         case TYPEAPPLY:
 995             return symbolFor(((JCTypeApply) node).clazz);
 996         case ANNOTATION:
 997         case TYPE_ANNOTATION:
 998         case TYPEPARAMETER:
 999             if (node.type != null)
1000                 return node.type.tsym;
1001             return null;
1002         default:
1003             return null;
1004         }
1005     }
1006 
1007     public static boolean isDeclaration(JCTree node) {
1008         node = skipParens(node);
1009         switch (node.getTag()) {
1010         case PACKAGEDEF:
1011         case CLASSDEF:
1012         case METHODDEF:
1013         case VARDEF:
1014             return true;
1015         default:
1016             return false;
1017         }
1018     }
1019 
1020     /** If this tree is an identifier or a field, return its symbol,
1021      *  otherwise return null.
1022      */
1023     public static Symbol symbol(JCTree tree) {
1024         tree = skipParens(tree);
1025         switch (tree.getTag()) {
1026         case IDENT:
1027             return ((JCIdent) tree).sym;
1028         case SELECT:
1029             return ((JCFieldAccess) tree).sym;
1030         case TYPEAPPLY:
1031             return symbol(((JCTypeApply) tree).clazz);
1032         case ANNOTATED_TYPE:
1033             return symbol(((JCAnnotatedType) tree).underlyingType);
1034         case REFERENCE:
1035             return ((JCMemberReference) tree).sym;
1036         case CLASSDEF:
1037             return ((JCClassDecl) tree).sym;
1038         default:
1039             return null;
1040         }
1041     }
1042 
1043     /** If this tree has a modifiers field, return it otherwise return null
1044      */
1045     public static JCModifiers getModifiers(JCTree tree) {
1046         tree = skipParens(tree);
1047         switch (tree.getTag()) {
1048             case VARDEF:
1049                 return ((JCVariableDecl) tree).mods;
1050             case METHODDEF:
1051                 return ((JCMethodDecl) tree).mods;
1052             case CLASSDEF:
1053                 return ((JCClassDecl) tree).mods;
1054             case MODULEDEF:
1055                 return ((JCModuleDecl) tree).mods;
1056         default:
1057             return null;
1058         }
1059     }
1060 
1061     /** Return true if this is a nonstatic selection. */
1062     public static boolean nonstaticSelect(JCTree tree) {
1063         tree = skipParens(tree);
1064         if (!tree.hasTag(SELECT)) return false;
1065         JCFieldAccess s = (JCFieldAccess) tree;
1066         Symbol e = symbol(s.selected);
1067         return e == null || (e.kind != PCK && e.kind != TYP);
1068     }
1069 
1070     /** If this tree is an identifier or a field, set its symbol, otherwise skip.
1071      */
1072     public static void setSymbol(JCTree tree, Symbol sym) {
1073         tree = skipParens(tree);
1074         switch (tree.getTag()) {
1075         case IDENT:
1076             ((JCIdent) tree).sym = sym; break;
1077         case SELECT:
1078             ((JCFieldAccess) tree).sym = sym; break;
1079         default:
1080         }
1081     }
1082 
1083     /** If this tree is a declaration or a block, return its flags field,
1084      *  otherwise return 0.
1085      */
1086     public static long flags(JCTree tree) {
1087         switch (tree.getTag()) {
1088         case VARDEF:
1089             return ((JCVariableDecl) tree).mods.flags;
1090         case METHODDEF:
1091             return ((JCMethodDecl) tree).mods.flags;
1092         case CLASSDEF:
1093             return ((JCClassDecl) tree).mods.flags;
1094         case BLOCK:
1095             return ((JCBlock) tree).flags;
1096         default:
1097             return 0;
1098         }
1099     }
1100 
1101     /** Return first (smallest) flag in `flags':
1102      *  pre: flags != 0
1103      */
1104     public static long firstFlag(long flags) {
1105         long flag = 1;
1106         while ((flag & flags) == 0)
1107             flag = flag << 1;
1108         return flag;
1109     }
1110 
1111     /** Return flags as a string, separated by " ".
1112      */
1113     public static String flagNames(long flags) {
1114         return Flags.toString(flags & ExtendedStandardFlags).trim();
1115     }
1116 
1117     /** Operator precedences values.
1118      */
1119     public static final int
1120         notExpression = -1,   // not an expression
1121         noPrec = 0,           // no enclosing expression
1122         assignPrec = 1,
1123         assignopPrec = 2,
1124         condPrec = 3,
1125         orPrec = 4,
1126         andPrec = 5,
1127         bitorPrec = 6,
1128         bitxorPrec = 7,
1129         bitandPrec = 8,
1130         eqPrec = 9,
1131         ordPrec = 10,
1132         shiftPrec = 11,
1133         addPrec = 12,
1134         mulPrec = 13,
1135         prefixPrec = 14,
1136         postfixPrec = 15,
1137         precCount = 16;
1138 
1139 
1140     /** Map operators to their precedence levels.
1141      */
1142     public static int opPrec(JCTree.Tag op) {
1143         switch(op) {
1144         case POS:
1145         case NEG:
1146         case NOT:
1147         case COMPL:
1148         case PREINC:
1149         case PREDEC: return prefixPrec;
1150         case POSTINC:
1151         case POSTDEC:
1152         case NULLCHK: return postfixPrec;
1153         case ASSIGN: return assignPrec;
1154         case BITOR_ASG:
1155         case BITXOR_ASG:
1156         case BITAND_ASG:
1157         case SL_ASG:
1158         case SR_ASG:
1159         case USR_ASG:
1160         case PLUS_ASG:
1161         case MINUS_ASG:
1162         case MUL_ASG:
1163         case DIV_ASG:
1164         case MOD_ASG: return assignopPrec;
1165         case OR: return orPrec;
1166         case AND: return andPrec;
1167         case EQ:
1168         case NE: return eqPrec;
1169         case LT:
1170         case GT:
1171         case LE:
1172         case GE: return ordPrec;
1173         case BITOR: return bitorPrec;
1174         case BITXOR: return bitxorPrec;
1175         case BITAND: return bitandPrec;
1176         case SL:
1177         case SR:
1178         case USR: return shiftPrec;
1179         case PLUS:
1180         case MINUS: return addPrec;
1181         case MUL:
1182         case DIV:
1183         case MOD: return mulPrec;
1184         case TYPETEST: return ordPrec;
1185         default: throw new AssertionError();
1186         }
1187     }
1188 
1189     static Tree.Kind tagToKind(JCTree.Tag tag) {
1190         switch (tag) {
1191         // Postfix expressions
1192         case POSTINC:           // _ ++
1193             return Tree.Kind.POSTFIX_INCREMENT;
1194         case POSTDEC:           // _ --
1195             return Tree.Kind.POSTFIX_DECREMENT;
1196 
1197         // Unary operators
1198         case PREINC:            // ++ _
1199             return Tree.Kind.PREFIX_INCREMENT;
1200         case PREDEC:            // -- _
1201             return Tree.Kind.PREFIX_DECREMENT;
1202         case POS:               // +
1203             return Tree.Kind.UNARY_PLUS;
1204         case NEG:               // -
1205             return Tree.Kind.UNARY_MINUS;
1206         case COMPL:             // ~
1207             return Tree.Kind.BITWISE_COMPLEMENT;
1208         case NOT:               // !
1209             return Tree.Kind.LOGICAL_COMPLEMENT;
1210 
1211         // Binary operators
1212 
1213         // Multiplicative operators
1214         case MUL:               // *
1215             return Tree.Kind.MULTIPLY;
1216         case DIV:               // /
1217             return Tree.Kind.DIVIDE;
1218         case MOD:               // %
1219             return Tree.Kind.REMAINDER;
1220 
1221         // Additive operators
1222         case PLUS:              // +
1223             return Tree.Kind.PLUS;
1224         case MINUS:             // -
1225             return Tree.Kind.MINUS;
1226 
1227         // Shift operators
1228         case SL:                // <<
1229             return Tree.Kind.LEFT_SHIFT;
1230         case SR:                // >>
1231             return Tree.Kind.RIGHT_SHIFT;
1232         case USR:               // >>>
1233             return Tree.Kind.UNSIGNED_RIGHT_SHIFT;
1234 
1235         // Relational operators
1236         case LT:                // <
1237             return Tree.Kind.LESS_THAN;
1238         case GT:                // >
1239             return Tree.Kind.GREATER_THAN;
1240         case LE:                // <=
1241             return Tree.Kind.LESS_THAN_EQUAL;
1242         case GE:                // >=
1243             return Tree.Kind.GREATER_THAN_EQUAL;
1244 
1245         // Equality operators
1246         case EQ:                // ==
1247             return Tree.Kind.EQUAL_TO;
1248         case NE:                // !=
1249             return Tree.Kind.NOT_EQUAL_TO;
1250 
1251         // Bitwise and logical operators
1252         case BITAND:            // &
1253             return Tree.Kind.AND;
1254         case BITXOR:            // ^
1255             return Tree.Kind.XOR;
1256         case BITOR:             // |
1257             return Tree.Kind.OR;
1258 
1259         // Conditional operators
1260         case AND:               // &&
1261             return Tree.Kind.CONDITIONAL_AND;
1262         case OR:                // ||
1263             return Tree.Kind.CONDITIONAL_OR;
1264 
1265         // Assignment operators
1266         case MUL_ASG:           // *=
1267             return Tree.Kind.MULTIPLY_ASSIGNMENT;
1268         case DIV_ASG:           // /=
1269             return Tree.Kind.DIVIDE_ASSIGNMENT;
1270         case MOD_ASG:           // %=
1271             return Tree.Kind.REMAINDER_ASSIGNMENT;
1272         case PLUS_ASG:          // +=
1273             return Tree.Kind.PLUS_ASSIGNMENT;
1274         case MINUS_ASG:         // -=
1275             return Tree.Kind.MINUS_ASSIGNMENT;
1276         case SL_ASG:            // <<=
1277             return Tree.Kind.LEFT_SHIFT_ASSIGNMENT;
1278         case SR_ASG:            // >>=
1279             return Tree.Kind.RIGHT_SHIFT_ASSIGNMENT;
1280         case USR_ASG:           // >>>=
1281             return Tree.Kind.UNSIGNED_RIGHT_SHIFT_ASSIGNMENT;
1282         case BITAND_ASG:        // &=
1283             return Tree.Kind.AND_ASSIGNMENT;
1284         case BITXOR_ASG:        // ^=
1285             return Tree.Kind.XOR_ASSIGNMENT;
1286         case BITOR_ASG:         // |=
1287             return Tree.Kind.OR_ASSIGNMENT;
1288 
1289         // Null check (implementation detail), for example, __.getClass()
1290         case NULLCHK:
1291             return Tree.Kind.OTHER;
1292 
1293         case ANNOTATION:
1294             return Tree.Kind.ANNOTATION;
1295         case TYPE_ANNOTATION:
1296             return Tree.Kind.TYPE_ANNOTATION;
1297 
1298         case EXPORTS:
1299             return Tree.Kind.EXPORTS;
1300         case OPENS:
1301             return Tree.Kind.OPENS;
1302 
1303         default:
1304             return null;
1305         }
1306     }
1307 
1308     /**
1309      * Returns the underlying type of the tree if it is an annotated type,
1310      * or the tree itself otherwise.
1311      */
1312     public static JCExpression typeIn(JCExpression tree) {
1313         switch (tree.getTag()) {
1314         case ANNOTATED_TYPE:
1315             return ((JCAnnotatedType)tree).underlyingType;
1316         case IDENT: /* simple names */
1317         case TYPEIDENT: /* primitive name */
1318         case SELECT: /* qualified name */
1319         case TYPEARRAY: /* array types */
1320         case WILDCARD: /* wild cards */
1321         case TYPEPARAMETER: /* type parameters */
1322         case TYPEAPPLY: /* parameterized types */
1323         case ERRONEOUS: /* error tree TODO: needed for BadCast JSR308 test case. Better way? */
1324             return tree;
1325         default:
1326             throw new AssertionError("Unexpected type tree: " + tree);
1327         }
1328     }
1329 
1330     /* Return the inner-most type of a type tree.
1331      * For an array that contains an annotated type, return that annotated type.
1332      * TODO: currently only used by Pretty. Describe behavior better.
1333      */
1334     public static JCTree innermostType(JCTree type, boolean skipAnnos) {
1335         JCTree lastAnnotatedType = null;
1336         JCTree cur = type;
1337         loop: while (true) {
1338             switch (cur.getTag()) {
1339             case TYPEARRAY:
1340                 lastAnnotatedType = null;
1341                 cur = ((JCArrayTypeTree)cur).elemtype;
1342                 break;
1343             case WILDCARD:
1344                 lastAnnotatedType = null;
1345                 cur = ((JCWildcard)cur).inner;
1346                 break;
1347             case ANNOTATED_TYPE:
1348                 lastAnnotatedType = cur;
1349                 cur = ((JCAnnotatedType)cur).underlyingType;
1350                 break;
1351             default:
1352                 break loop;
1353             }
1354         }
1355         if (!skipAnnos && lastAnnotatedType!=null) {
1356             return lastAnnotatedType;
1357         } else {
1358             return cur;
1359         }
1360     }
1361 
1362     private static class TypeAnnotationFinder extends TreeScanner {
1363         public boolean foundTypeAnno = false;
1364 
1365         @Override
1366         public void scan(JCTree tree) {
1367             if (foundTypeAnno || tree == null)
1368                 return;
1369             super.scan(tree);
1370         }
1371 
1372         public void visitAnnotation(JCAnnotation tree) {
1373             foundTypeAnno = foundTypeAnno || tree.hasTag(TYPE_ANNOTATION);
1374         }
1375     }
1376 
1377     public static boolean containsTypeAnnotation(JCTree e) {
1378         TypeAnnotationFinder finder = new TypeAnnotationFinder();
1379         finder.scan(e);
1380         return finder.foundTypeAnno;
1381     }
1382 
1383     public static boolean isModuleInfo(JCCompilationUnit tree) {
1384         return tree.sourcefile.isNameCompatible("module-info", JavaFileObject.Kind.SOURCE)
1385                 && tree.getModuleDecl() != null;
1386     }
1387 
1388     public static boolean isPackageInfo(JCCompilationUnit tree) {
1389         return tree.sourcefile.isNameCompatible("package-info", JavaFileObject.Kind.SOURCE);
1390     }
1391 
1392     public static boolean isErrorEnumSwitch(JCExpression selector, List<JCCase> cases) {
1393         return selector.type.tsym.kind == Kinds.Kind.ERR &&
1394                cases.stream().flatMap(c -> c.labels.stream())
1395                              .filter(l -> l.hasTag(CONSTANTCASELABEL))
1396                              .map(l -> ((JCConstantCaseLabel) l).expr)
1397                              .allMatch(p -> p.hasTag(IDENT));
1398     }
1399 
1400     public static Type primaryPatternType(JCTree pat) {
1401         return switch (pat.getTag()) {
1402             case BINDINGPATTERN -> pat.type;
1403             case RECORDPATTERN -> ((JCRecordPattern) pat).type;
1404             case ANYPATTERN -> ((JCAnyPattern) pat).type;
1405             default -> throw new AssertionError();
1406         };
1407     }
1408 
1409     public static JCTree primaryPatternTypeTree(JCTree pat) {
1410         return switch (pat.getTag()) {
1411             case BINDINGPATTERN -> ((JCBindingPattern) pat).var.vartype;
1412             case RECORDPATTERN -> ((JCRecordPattern) pat).deconstructor;
1413             default -> throw new AssertionError();
1414         };
1415     }
1416 
1417     public static boolean expectedExhaustive(JCSwitch tree) {
1418         return tree.patternSwitch ||
1419                tree.cases.stream()
1420                          .flatMap(c -> c.labels.stream())
1421                          .anyMatch(l -> TreeInfo.isNullCaseLabel(l));
1422     }
1423 
1424     public static boolean unguardedCase(JCCase cse) {
1425         JCExpression guard = cse.guard;
1426         if (guard == null) {
1427             return true;
1428         }
1429         return isBooleanWithValue(guard, 1);
1430     }
1431 
1432     public static boolean isBooleanWithValue(JCExpression guard, int value) {
1433         var constValue = guard.type.constValue();
1434         return constValue != null &&
1435                 guard.type.hasTag(BOOLEAN) &&
1436                 ((int) constValue) == value;
1437     }
1438 
1439     public static boolean isNullCaseLabel(JCCaseLabel label) {
1440         return label.hasTag(CONSTANTCASELABEL) &&
1441                TreeInfo.isNull(((JCConstantCaseLabel) label).expr);
1442     }
1443 }