1 /*
   2  * Copyright (c) 1999, 2021, 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.code;
  27 
  28 import java.lang.annotation.Annotation;
  29 import java.lang.annotation.Inherited;
  30 import java.util.Collections;
  31 import java.util.EnumSet;
  32 import java.util.HashMap;
  33 import java.util.Map;
  34 import java.util.Set;
  35 import java.util.concurrent.Callable;
  36 import java.util.function.Supplier;
  37 import java.util.function.Predicate;
  38 
  39 import javax.lang.model.element.Element;
  40 import javax.lang.model.element.ElementKind;
  41 import javax.lang.model.element.ElementVisitor;
  42 import javax.lang.model.element.ExecutableElement;
  43 import javax.lang.model.element.Modifier;
  44 import javax.lang.model.element.ModuleElement;
  45 import javax.lang.model.element.NestingKind;
  46 import javax.lang.model.element.PackageElement;
  47 import javax.lang.model.element.RecordComponentElement;
  48 import javax.lang.model.element.TypeElement;
  49 import javax.lang.model.element.TypeParameterElement;
  50 import javax.lang.model.element.VariableElement;
  51 import javax.tools.JavaFileManager;
  52 import javax.tools.JavaFileObject;
  53 
  54 import com.sun.tools.javac.code.Kinds.Kind;
  55 import com.sun.tools.javac.comp.Annotate.AnnotationTypeMetadata;
  56 import com.sun.tools.javac.code.Type.*;
  57 import com.sun.tools.javac.comp.Attr;
  58 import com.sun.tools.javac.comp.AttrContext;
  59 import com.sun.tools.javac.comp.Env;
  60 import com.sun.tools.javac.jvm.*;
  61 import com.sun.tools.javac.jvm.PoolConstant;
  62 import com.sun.tools.javac.tree.JCTree;
  63 import com.sun.tools.javac.tree.JCTree.JCAnnotation;
  64 import com.sun.tools.javac.tree.JCTree.JCFieldAccess;
  65 import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
  66 import com.sun.tools.javac.tree.JCTree.Tag;
  67 import com.sun.tools.javac.util.*;
  68 import com.sun.tools.javac.util.DefinedBy.Api;
  69 import com.sun.tools.javac.util.List;
  70 import com.sun.tools.javac.util.Name;
  71 
  72 import static com.sun.tools.javac.code.Flags.*;
  73 import static com.sun.tools.javac.code.Kinds.*;
  74 import static com.sun.tools.javac.code.Kinds.Kind.*;
  75 import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
  76 import com.sun.tools.javac.code.Scope.WriteableScope;
  77 import static com.sun.tools.javac.code.TypeTag.CLASS;
  78 import static com.sun.tools.javac.code.TypeTag.FORALL;
  79 import static com.sun.tools.javac.code.TypeTag.TYPEVAR;
  80 import static com.sun.tools.javac.jvm.ByteCodes.iadd;
  81 import static com.sun.tools.javac.jvm.ByteCodes.ishll;
  82 import static com.sun.tools.javac.jvm.ByteCodes.lushrl;
  83 import static com.sun.tools.javac.jvm.ByteCodes.lxor;
  84 import static com.sun.tools.javac.jvm.ByteCodes.string_add;
  85 
  86 /** Root class for Java symbols. It contains subclasses
  87  *  for specific sorts of symbols, such as variables, methods and operators,
  88  *  types, packages. Each subclass is represented as a static inner class
  89  *  inside Symbol.
  90  *
  91  *  <p><b>This is NOT part of any supported API.
  92  *  If you write code that depends on this, you do so at your own risk.
  93  *  This code and its internal interfaces are subject to change or
  94  *  deletion without notice.</b>
  95  */
  96 public abstract class Symbol extends AnnoConstruct implements PoolConstant, Element {
  97 
  98     /** The kind of this symbol.
  99      *  @see Kinds
 100      */
 101     public Kind kind;
 102 
 103     /** The flags of this symbol.
 104      */
 105     public long flags_field;
 106 
 107     /** An accessor method for the flags of this symbol.
 108      *  Flags of class symbols should be accessed through the accessor
 109      *  method to make sure that the class symbol is loaded.
 110      */
 111     public long flags() { return flags_field; }
 112 
 113     /** The name of this symbol in Utf8 representation.
 114      */
 115     public Name name;
 116 
 117     /** The type of this symbol.
 118      */
 119     public Type type;
 120 
 121     /** The owner of this symbol.
 122      */
 123     public Symbol owner;
 124 
 125     /** The completer of this symbol.
 126      * This should never equal null (NULL_COMPLETER should be used instead).
 127      */
 128     public Completer completer;
 129 
 130     /** A cache for the type erasure of this symbol.
 131      */
 132     public Type erasure_field;
 133 
 134     // <editor-fold defaultstate="collapsed" desc="annotations">
 135 
 136     /** The attributes of this symbol are contained in this
 137      * SymbolMetadata. The SymbolMetadata instance is NOT immutable.
 138      */
 139     protected SymbolMetadata metadata;
 140 
 141 
 142     /** An accessor method for the attributes of this symbol.
 143      *  Attributes of class symbols should be accessed through the accessor
 144      *  method to make sure that the class symbol is loaded.
 145      */
 146     public List<Attribute.Compound> getRawAttributes() {
 147         return (metadata == null)
 148                 ? List.nil()
 149                 : metadata.getDeclarationAttributes();
 150     }
 151 
 152     /** An accessor method for the type attributes of this symbol.
 153      *  Attributes of class symbols should be accessed through the accessor
 154      *  method to make sure that the class symbol is loaded.
 155      */
 156     public List<Attribute.TypeCompound> getRawTypeAttributes() {
 157         return (metadata == null)
 158                 ? List.nil()
 159                 : metadata.getTypeAttributes();
 160     }
 161 
 162     /** Fetch a particular annotation from a symbol. */
 163     public Attribute.Compound attribute(Symbol anno) {
 164         for (Attribute.Compound a : getRawAttributes()) {
 165             if (a.type.tsym == anno) return a;
 166         }
 167         return null;
 168     }
 169 
 170     public boolean annotationsPendingCompletion() {
 171         return metadata == null ? false : metadata.pendingCompletion();
 172     }
 173 
 174     public void appendAttributes(List<Attribute.Compound> l) {
 175         if (l.nonEmpty()) {
 176             initedMetadata().append(l);
 177         }
 178     }
 179 
 180     public void appendClassInitTypeAttributes(List<Attribute.TypeCompound> l) {
 181         if (l.nonEmpty()) {
 182             initedMetadata().appendClassInitTypeAttributes(l);
 183         }
 184     }
 185 
 186     public void appendInitTypeAttributes(List<Attribute.TypeCompound> l) {
 187         if (l.nonEmpty()) {
 188             initedMetadata().appendInitTypeAttributes(l);
 189         }
 190     }
 191 
 192     public void appendUniqueTypeAttributes(List<Attribute.TypeCompound> l) {
 193         if (l.nonEmpty()) {
 194             initedMetadata().appendUniqueTypes(l);
 195         }
 196     }
 197 
 198     public List<Attribute.TypeCompound> getClassInitTypeAttributes() {
 199         return (metadata == null)
 200                 ? List.nil()
 201                 : metadata.getClassInitTypeAttributes();
 202     }
 203 
 204     public List<Attribute.TypeCompound> getInitTypeAttributes() {
 205         return (metadata == null)
 206                 ? List.nil()
 207                 : metadata.getInitTypeAttributes();
 208     }
 209 
 210     public void setInitTypeAttributes(List<Attribute.TypeCompound> l) {
 211         initedMetadata().setInitTypeAttributes(l);
 212     }
 213 
 214     public void setClassInitTypeAttributes(List<Attribute.TypeCompound> l) {
 215         initedMetadata().setClassInitTypeAttributes(l);
 216     }
 217 
 218     public List<Attribute.Compound> getDeclarationAttributes() {
 219         return (metadata == null)
 220                 ? List.nil()
 221                 : metadata.getDeclarationAttributes();
 222     }
 223 
 224     public boolean hasAnnotations() {
 225         return (metadata != null && !metadata.isEmpty());
 226     }
 227 
 228     public boolean hasTypeAnnotations() {
 229         return (metadata != null && !metadata.isTypesEmpty());
 230     }
 231 
 232     public boolean isCompleted() {
 233         return completer.isTerminal();
 234     }
 235 
 236     public void prependAttributes(List<Attribute.Compound> l) {
 237         if (l.nonEmpty()) {
 238             initedMetadata().prepend(l);
 239         }
 240     }
 241 
 242     public void resetAnnotations() {
 243         initedMetadata().reset();
 244     }
 245 
 246     public void setAttributes(Symbol other) {
 247         if (metadata != null || other.metadata != null) {
 248             initedMetadata().setAttributes(other.metadata);
 249         }
 250     }
 251 
 252     public void setDeclarationAttributes(List<Attribute.Compound> a) {
 253         if (metadata != null || a.nonEmpty()) {
 254             initedMetadata().setDeclarationAttributes(a);
 255         }
 256     }
 257 
 258     public void setTypeAttributes(List<Attribute.TypeCompound> a) {
 259         if (metadata != null || a.nonEmpty()) {
 260             if (metadata == null)
 261                 metadata = new SymbolMetadata(this);
 262             metadata.setTypeAttributes(a);
 263         }
 264     }
 265 
 266     private SymbolMetadata initedMetadata() {
 267         if (metadata == null)
 268             metadata = new SymbolMetadata(this);
 269         return metadata;
 270     }
 271 
 272     /** This method is intended for debugging only. */
 273     public SymbolMetadata getMetadata() {
 274         return metadata;
 275     }
 276 
 277     // </editor-fold>
 278 
 279     /** Construct a symbol with given kind, flags, name, type and owner.
 280      */
 281     public Symbol(Kind kind, long flags, Name name, Type type, Symbol owner) {
 282         this.kind = kind;
 283         this.flags_field = flags;
 284         this.type = type;
 285         this.owner = owner;
 286         this.completer = Completer.NULL_COMPLETER;
 287         this.erasure_field = null;
 288         this.name = name;
 289     }
 290 
 291     @Override
 292     public int poolTag() {
 293         throw new AssertionError("Invalid pool entry");
 294     }
 295 
 296     /** Clone this symbol with new owner.
 297      *  Legal only for fields and methods.
 298      */
 299     public Symbol clone(Symbol newOwner) {
 300         throw new AssertionError();
 301     }
 302 
 303     public <R, P> R accept(Symbol.Visitor<R, P> v, P p) {
 304         return v.visitSymbol(this, p);
 305     }
 306 
 307     /** The Java source which this symbol represents.
 308      *  A description of this symbol; overrides Object.
 309      */
 310     public String toString() {
 311         return name.toString();
 312     }
 313 
 314     /** A Java source description of the location of this symbol; used for
 315      *  error reporting.
 316      *
 317      * @return null if the symbol is a package or a toplevel class defined in
 318      * the default package; otherwise, the owner symbol is returned
 319      */
 320     public Symbol location() {
 321         if (owner.name == null || (owner.name.isEmpty() &&
 322                                    (owner.flags() & BLOCK) == 0 &&
 323                                    owner.kind != PCK &&
 324                                    owner.kind != TYP)) {
 325             return null;
 326         }
 327         return owner;
 328     }
 329 
 330     public Symbol location(Type site, Types types) {
 331         if (owner.name == null || owner.name.isEmpty()) {
 332             return location();
 333         }
 334         if (owner.type.hasTag(CLASS)) {
 335             Type ownertype = types.asOuterSuper(site, owner);
 336             if (ownertype != null) return ownertype.tsym;
 337         }
 338         return owner;
 339     }
 340 
 341     public Symbol baseSymbol() {
 342         return this;
 343     }
 344 
 345     /** The symbol's erased type.
 346      */
 347     public Type erasure(Types types) {
 348         if (erasure_field == null)
 349             erasure_field = types.erasure(type);
 350         return erasure_field;
 351     }
 352 
 353     /** The external type of a symbol. This is the symbol's erased type
 354      *  except for constructors of inner classes which get the enclosing
 355      *  instance class added as first argument.
 356      */
 357     public Type externalType(Types types) {
 358         Type t = erasure(types);
 359         if (name == name.table.names.init && owner.hasOuterInstance()) {
 360             Type outerThisType = types.erasure(owner.type.getEnclosingType());
 361             return new MethodType(t.getParameterTypes().prepend(outerThisType),
 362                                   t.getReturnType(),
 363                                   t.getThrownTypes(),
 364                                   t.tsym);
 365         } else {
 366             return t;
 367         }
 368     }
 369 
 370     public boolean isDeprecated() {
 371         return (flags_field & DEPRECATED) != 0;
 372     }
 373 
 374     public boolean hasDeprecatedAnnotation() {
 375         return (flags_field & DEPRECATED_ANNOTATION) != 0;
 376     }
 377 
 378     public boolean isDeprecatedForRemoval() {
 379         return (flags_field & DEPRECATED_REMOVAL) != 0;
 380     }
 381 
 382     public boolean isPreviewApi() {
 383         return (flags_field & PREVIEW_API) != 0;
 384     }
 385 
 386     public boolean isDeprecatableViaAnnotation() {
 387         switch (getKind()) {
 388             case LOCAL_VARIABLE:
 389             case PACKAGE:
 390             case PARAMETER:
 391             case RESOURCE_VARIABLE:
 392             case EXCEPTION_PARAMETER:
 393                 return false;
 394             default:
 395                 return true;
 396         }
 397     }
 398 
 399     public boolean isStatic() {
 400         return
 401             (flags() & STATIC) != 0 ||
 402             (owner.flags() & INTERFACE) != 0 && kind != MTH &&
 403              name != name.table.names._this;
 404     }
 405 
 406     public boolean isInterface() {
 407         return (flags() & INTERFACE) != 0;
 408     }
 409 
 410     public boolean isAbstract() {
 411         return (flags_field & ABSTRACT) != 0;
 412     }
 413 
 414     public boolean isPrivate() {
 415         return (flags_field & Flags.AccessFlags) == PRIVATE;
 416     }
 417 
 418     public boolean isPublic() {
 419         return (flags_field & Flags.AccessFlags) == PUBLIC;
 420     }
 421 
 422     public boolean isEnum() {
 423         return (flags() & ENUM) != 0;
 424     }
 425 
 426     public boolean isSealed() {
 427         return (flags_field & SEALED) != 0;
 428     }
 429 
 430     public boolean isNonSealed() {
 431         return (flags_field & NON_SEALED) != 0;
 432     }
 433 
 434     public boolean isFinal() {
 435         return (flags_field & FINAL) != 0;
 436     }
 437 
 438    /** Is this symbol declared (directly or indirectly) local
 439      *  to a method or variable initializer?
 440      *  Also includes fields of inner classes which are in
 441      *  turn local to a method or variable initializer.
 442      */
 443     public boolean isDirectlyOrIndirectlyLocal() {
 444         return
 445             (owner.kind.matches(KindSelector.VAL_MTH) ||
 446              (owner.kind == TYP && owner.isDirectlyOrIndirectlyLocal()));
 447     }
 448 
 449     /** Has this symbol an empty name? This includes anonymous
 450      *  inner classes.
 451      */
 452     public boolean isAnonymous() {
 453         return name.isEmpty();
 454     }
 455 
 456     /** Is this symbol a constructor?
 457      */
 458     public boolean isConstructor() {
 459         return name == name.table.names.init;
 460     }
 461 
 462     public boolean isDynamic() {
 463         return false;
 464     }
 465 
 466     /** The fully qualified name of this symbol.
 467      *  This is the same as the symbol's name except for class symbols,
 468      *  which are handled separately.
 469      */
 470     public Name getQualifiedName() {
 471         return name;
 472     }
 473 
 474     /** The fully qualified name of this symbol after converting to flat
 475      *  representation. This is the same as the symbol's name except for
 476      *  class symbols, which are handled separately.
 477      */
 478     public Name flatName() {
 479         return getQualifiedName();
 480     }
 481 
 482     /** If this is a class or package, its members, otherwise null.
 483      */
 484     public WriteableScope members() {
 485         return null;
 486     }
 487 
 488     /** A class is an inner class if it it has an enclosing instance class.
 489      */
 490     public boolean isInner() {
 491         return kind == TYP && type.getEnclosingType().hasTag(CLASS);
 492     }
 493 
 494     /** An inner class has an outer instance if it is not an interface
 495      *  it has an enclosing instance class which might be referenced from the class.
 496      *  Nested classes can see instance members of their enclosing class.
 497      *  Their constructors carry an additional this$n parameter, inserted
 498      *  implicitly by the compiler.
 499      *
 500      *  @see #isInner
 501      */
 502     public boolean hasOuterInstance() {
 503         return
 504             type.getEnclosingType().hasTag(CLASS) && (flags() & (INTERFACE | NOOUTERTHIS)) == 0;
 505     }
 506 
 507     /** The closest enclosing class of this symbol's declaration.
 508      *  Warning: this (misnamed) method returns the receiver itself
 509      *  when the receiver is a class (as opposed to its enclosing
 510      *  class as one may be misled to believe.)
 511      */
 512     public ClassSymbol enclClass() {
 513         Symbol c = this;
 514         while (c != null &&
 515                (!c.kind.matches(KindSelector.TYP) || !c.type.hasTag(CLASS))) {
 516             c = c.owner;
 517         }
 518         return (ClassSymbol)c;
 519     }
 520 
 521     /** The outermost class which indirectly owns this symbol.
 522      */
 523     public ClassSymbol outermostClass() {
 524         Symbol sym = this;
 525         Symbol prev = null;
 526         while (sym.kind != PCK) {
 527             prev = sym;
 528             sym = sym.owner;
 529         }
 530         return (ClassSymbol) prev;
 531     }
 532 
 533     /** The package which indirectly owns this symbol.
 534      */
 535     public PackageSymbol packge() {
 536         Symbol sym = this;
 537         while (sym.kind != PCK) {
 538             sym = sym.owner;
 539         }
 540         return (PackageSymbol) sym;
 541     }
 542 
 543     /** Is this symbol a subclass of `base'? Only defined for ClassSymbols.
 544      */
 545     public boolean isSubClass(Symbol base, Types types) {
 546         throw new AssertionError("isSubClass " + this);
 547     }
 548 
 549     /** Fully check membership: hierarchy, protection, and hiding.
 550      *  Does not exclude methods not inherited due to overriding.
 551      */
 552     public boolean isMemberOf(TypeSymbol clazz, Types types) {
 553         return
 554             owner == clazz ||
 555             clazz.isSubClass(owner, types) &&
 556             isInheritedIn(clazz, types) &&
 557             !hiddenIn((ClassSymbol)clazz, types);
 558     }
 559 
 560     /** Is this symbol the same as or enclosed by the given class? */
 561     public boolean isEnclosedBy(ClassSymbol clazz) {
 562         for (Symbol sym = this; sym.kind != PCK; sym = sym.owner)
 563             if (sym == clazz) return true;
 564         return false;
 565     }
 566 
 567     private boolean hiddenIn(ClassSymbol clazz, Types types) {
 568         Symbol sym = hiddenInInternal(clazz, types);
 569         Assert.check(sym != null, "the result of hiddenInInternal() can't be null");
 570         /* If we find the current symbol then there is no symbol hiding it
 571          */
 572         return sym != this;
 573     }
 574 
 575     /** This method looks in the supertypes graph that has the current class as the
 576      * initial node, till it finds the current symbol or another symbol that hides it.
 577      * If the current class has more than one supertype (extends one class and
 578      * implements one or more interfaces) then null can be returned, meaning that
 579      * a wrong path in the supertypes graph was selected. Null can only be returned
 580      * as a temporary value, as a result of the recursive call.
 581      */
 582     private Symbol hiddenInInternal(ClassSymbol currentClass, Types types) {
 583         if (currentClass == owner) {
 584             return this;
 585         }
 586         for (Symbol sym : currentClass.members().getSymbolsByName(name)) {
 587             if (sym.kind == kind &&
 588                     (kind != MTH ||
 589                     (sym.flags() & STATIC) != 0 &&
 590                     types.isSubSignature(sym.type, type))) {
 591                 return sym;
 592             }
 593         }
 594         Symbol hiddenSym = null;
 595         for (Type st : types.interfaces(currentClass.type)
 596                 .prepend(types.supertype(currentClass.type))) {
 597             if (st != null && (st.hasTag(CLASS))) {
 598                 Symbol sym = hiddenInInternal((ClassSymbol)st.tsym, types);
 599                 if (sym == this) {
 600                     return this;
 601                 } else if (sym != null) {
 602                     hiddenSym = sym;
 603                 }
 604             }
 605         }
 606         return hiddenSym;
 607     }
 608 
 609     /** Is this symbol accessible in a given class?
 610      *  PRE: If symbol's owner is a interface,
 611      *       it is already assumed that the interface is a superinterface
 612      *       the given class.
 613      *  @param clazz  The class for which we want to establish membership.
 614      *                This must be a subclass of the member's owner.
 615      */
 616     public final boolean isAccessibleIn(Symbol clazz, Types types) {
 617         switch ((int)(flags_field & Flags.AccessFlags)) {
 618         default: // error recovery
 619         case PUBLIC:
 620             return true;
 621         case PRIVATE:
 622             return this.owner == clazz;
 623         case PROTECTED:
 624             // we model interfaces as extending Object
 625             return (clazz.flags() & INTERFACE) == 0;
 626         case 0:
 627             PackageSymbol thisPackage = this.packge();
 628             for (Symbol sup = clazz;
 629                  sup != null && sup != this.owner;
 630                  sup = types.supertype(sup.type).tsym) {
 631                 while (sup.type.hasTag(TYPEVAR))
 632                     sup = sup.type.getUpperBound().tsym;
 633                 if (sup.type.isErroneous())
 634                     return true; // error recovery
 635                 if ((sup.flags() & COMPOUND) != 0)
 636                     continue;
 637                 if (sup.packge() != thisPackage)
 638                     return false;
 639             }
 640             return (clazz.flags() & INTERFACE) == 0;
 641         }
 642     }
 643 
 644     /** Is this symbol inherited into a given class?
 645      *  PRE: If symbol's owner is a interface,
 646      *       it is already assumed that the interface is a superinterface
 647      *       of the given class.
 648      *  @param clazz  The class for which we want to establish membership.
 649      *                This must be a subclass of the member's owner.
 650      */
 651     public boolean isInheritedIn(Symbol clazz, Types types) {
 652         return isAccessibleIn(clazz, types);
 653     }
 654 
 655     /** The (variable or method) symbol seen as a member of given
 656      *  class type`site' (this might change the symbol's type).
 657      *  This is used exclusively for producing diagnostics.
 658      */
 659     public Symbol asMemberOf(Type site, Types types) {
 660         throw new AssertionError();
 661     }
 662 
 663     /** Does this method symbol override `other' symbol, when both are seen as
 664      *  members of class `origin'?  It is assumed that _other is a member
 665      *  of origin.
 666      *
 667      *  It is assumed that both symbols have the same name.  The static
 668      *  modifier is ignored for this test.
 669      *
 670      *  See JLS 8.4.6.1 (without transitivity) and 8.4.6.4
 671      */
 672     public boolean overrides(Symbol _other, TypeSymbol origin, Types types, boolean checkResult) {
 673         return false;
 674     }
 675 
 676     /** Complete the elaboration of this symbol's definition.
 677      */
 678     public void complete() throws CompletionFailure {
 679         if (completer != Completer.NULL_COMPLETER) {
 680             Completer c = completer;
 681             completer = Completer.NULL_COMPLETER;
 682             c.complete(this);
 683         }
 684     }
 685 
 686     public void apiComplete() throws CompletionFailure {
 687         try {
 688             complete();
 689         } catch (CompletionFailure cf) {
 690             cf.dcfh.handleAPICompletionFailure(cf);
 691         }
 692     }
 693 
 694     /** True if the symbol represents an entity that exists.
 695      */
 696     public boolean exists() {
 697         return true;
 698     }
 699 
 700     @DefinedBy(Api.LANGUAGE_MODEL)
 701     public Type asType() {
 702         return type;
 703     }
 704 
 705     @DefinedBy(Api.LANGUAGE_MODEL)
 706     public Symbol getEnclosingElement() {
 707         return owner;
 708     }
 709 
 710     @DefinedBy(Api.LANGUAGE_MODEL)
 711     public ElementKind getKind() {
 712         return ElementKind.OTHER;       // most unkind
 713     }
 714 
 715     @DefinedBy(Api.LANGUAGE_MODEL)
 716     public Set<Modifier> getModifiers() {
 717         apiComplete();
 718         return Flags.asModifierSet(flags());
 719     }
 720 
 721     @DefinedBy(Api.LANGUAGE_MODEL)
 722     public Name getSimpleName() {
 723         return name;
 724     }
 725 
 726     /**
 727      * This is the implementation for {@code
 728      * javax.lang.model.element.Element.getAnnotationMirrors()}.
 729      */
 730     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 731     public List<Attribute.Compound> getAnnotationMirrors() {
 732         apiComplete();
 733         return getRawAttributes();
 734     }
 735 
 736 
 737     // TODO: getEnclosedElements should return a javac List, fix in FilteredMemberList
 738     @DefinedBy(Api.LANGUAGE_MODEL)
 739     public java.util.List<Symbol> getEnclosedElements() {
 740         return List.nil();
 741     }
 742 
 743     public List<TypeVariableSymbol> getTypeParameters() {
 744         ListBuffer<TypeVariableSymbol> l = new ListBuffer<>();
 745         for (Type t : type.getTypeArguments()) {
 746             Assert.check(t.tsym.getKind() == ElementKind.TYPE_PARAMETER);
 747             l.append((TypeVariableSymbol)t.tsym);
 748         }
 749         return l.toList();
 750     }
 751 
 752     public static class DelegatedSymbol<T extends Symbol> extends Symbol {
 753         protected T other;
 754         public DelegatedSymbol(T other) {
 755             super(other.kind, other.flags_field, other.name, other.type, other.owner);
 756             this.other = other;
 757         }
 758         public String toString() { return other.toString(); }
 759         public Symbol location() { return other.location(); }
 760         public Symbol location(Type site, Types types) { return other.location(site, types); }
 761         public Symbol baseSymbol() { return other; }
 762         public Type erasure(Types types) { return other.erasure(types); }
 763         public Type externalType(Types types) { return other.externalType(types); }
 764         public boolean isDirectlyOrIndirectlyLocal() { return other.isDirectlyOrIndirectlyLocal(); }
 765         public boolean isConstructor() { return other.isConstructor(); }
 766         public Name getQualifiedName() { return other.getQualifiedName(); }
 767         public Name flatName() { return other.flatName(); }
 768         public WriteableScope members() { return other.members(); }
 769         public boolean isInner() { return other.isInner(); }
 770         public boolean hasOuterInstance() { return other.hasOuterInstance(); }
 771         public ClassSymbol enclClass() { return other.enclClass(); }
 772         public ClassSymbol outermostClass() { return other.outermostClass(); }
 773         public PackageSymbol packge() { return other.packge(); }
 774         public boolean isSubClass(Symbol base, Types types) { return other.isSubClass(base, types); }
 775         public boolean isMemberOf(TypeSymbol clazz, Types types) { return other.isMemberOf(clazz, types); }
 776         public boolean isEnclosedBy(ClassSymbol clazz) { return other.isEnclosedBy(clazz); }
 777         public boolean isInheritedIn(Symbol clazz, Types types) { return other.isInheritedIn(clazz, types); }
 778         public Symbol asMemberOf(Type site, Types types) { return other.asMemberOf(site, types); }
 779         public void complete() throws CompletionFailure { other.complete(); }
 780 
 781         @DefinedBy(Api.LANGUAGE_MODEL)
 782         public <R, P> R accept(ElementVisitor<R, P> v, P p) {
 783             return other.accept(v, p);
 784         }
 785 
 786         public <R, P> R accept(Symbol.Visitor<R, P> v, P p) {
 787             return v.visitSymbol(other, p);
 788         }
 789 
 790         public T getUnderlyingSymbol() {
 791             return other;
 792         }
 793     }
 794 
 795     /** A base class for Symbols representing types.
 796      */
 797     public static abstract class TypeSymbol extends Symbol {
 798         public TypeSymbol(Kind kind, long flags, Name name, Type type, Symbol owner) {
 799             super(kind, flags, name, type, owner);
 800         }
 801         /** form a fully qualified name from a name and an owner
 802          */
 803         public static Name formFullName(Name name, Symbol owner) {
 804             if (owner == null) return name;
 805             if ((owner.kind != ERR) &&
 806                 (owner.kind.matches(KindSelector.VAL_MTH) ||
 807                  (owner.kind == TYP && owner.type.hasTag(TYPEVAR))
 808                  )) return name;
 809             Name prefix = owner.getQualifiedName();
 810             if (prefix == null || prefix == prefix.table.names.empty)
 811                 return name;
 812             else return prefix.append('.', name);
 813         }
 814 
 815         /** form a fully qualified name from a name and an owner, after
 816          *  converting to flat representation
 817          */
 818         public static Name formFlatName(Name name, Symbol owner) {
 819             if (owner == null || owner.kind.matches(KindSelector.VAL_MTH) ||
 820                 (owner.kind == TYP && owner.type.hasTag(TYPEVAR))
 821                 ) return name;
 822             char sep = owner.kind == TYP ? '$' : '.';
 823             Name prefix = owner.flatName();
 824             if (prefix == null || prefix == prefix.table.names.empty)
 825                 return name;
 826             else return prefix.append(sep, name);
 827         }
 828 
 829         /**
 830          * A partial ordering between type symbols that refines the
 831          * class inheritance graph.
 832          *
 833          * Type variables always precede other kinds of symbols.
 834          */
 835         public final boolean precedes(TypeSymbol that, Types types) {
 836             if (this == that)
 837                 return false;
 838             if (type.hasTag(that.type.getTag())) {
 839                 if (type.hasTag(CLASS)) {
 840                     return
 841                         types.rank(that.type) < types.rank(this.type) ||
 842                         types.rank(that.type) == types.rank(this.type) &&
 843                         that.getQualifiedName().compareTo(this.getQualifiedName()) < 0;
 844                 } else if (type.hasTag(TYPEVAR)) {
 845                     return types.isSubtype(this.type, that.type);
 846                 }
 847             }
 848             return type.hasTag(TYPEVAR);
 849         }
 850 
 851         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 852         public List<Symbol> getEnclosedElements() {
 853             List<Symbol> list = List.nil();
 854             if (kind == TYP && type.hasTag(TYPEVAR)) {
 855                 return list;
 856             }
 857             apiComplete();
 858             for (Symbol sym : members().getSymbols(NON_RECURSIVE)) {
 859                 sym.apiComplete();
 860                 if ((sym.flags() & SYNTHETIC) == 0 && sym.owner == this && sym.kind != ERR) {
 861                     list = list.prepend(sym);
 862                 }
 863             }
 864             return list;
 865         }
 866 
 867         public AnnotationTypeMetadata getAnnotationTypeMetadata() {
 868             Assert.error("Only on ClassSymbol");
 869             return null; //unreachable
 870         }
 871 
 872         public boolean isAnnotationType() { return false; }
 873 
 874         @Override
 875         public <R, P> R accept(Symbol.Visitor<R, P> v, P p) {
 876             return v.visitTypeSymbol(this, p);
 877         }
 878     }
 879 
 880     /**
 881      * Type variables are represented by instances of this class.
 882      */
 883     public static class TypeVariableSymbol
 884             extends TypeSymbol implements TypeParameterElement {
 885 
 886         public TypeVariableSymbol(long flags, Name name, Type type, Symbol owner) {
 887             super(TYP, flags, name, type, owner);
 888         }
 889 
 890         @DefinedBy(Api.LANGUAGE_MODEL)
 891         public ElementKind getKind() {
 892             return ElementKind.TYPE_PARAMETER;
 893         }
 894 
 895         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 896         public Symbol getGenericElement() {
 897             return owner;
 898         }
 899 
 900         @DefinedBy(Api.LANGUAGE_MODEL)
 901         public List<Type> getBounds() {
 902             TypeVar t = (TypeVar)type;
 903             Type bound = t.getUpperBound();
 904             if (!bound.isCompound())
 905                 return List.of(bound);
 906             ClassType ct = (ClassType)bound;
 907             if (!ct.tsym.erasure_field.isInterface()) {
 908                 return ct.interfaces_field.prepend(ct.supertype_field);
 909             } else {
 910                 // No superclass was given in bounds.
 911                 // In this case, supertype is Object, erasure is first interface.
 912                 return ct.interfaces_field;
 913             }
 914         }
 915 
 916         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 917         public List<Attribute.Compound> getAnnotationMirrors() {
 918             // Declaration annotations on type variables are stored in type attributes
 919             // on the owner of the TypeVariableSymbol
 920             List<Attribute.TypeCompound> candidates = owner.getRawTypeAttributes();
 921             int index = owner.getTypeParameters().indexOf(this);
 922             List<Attribute.Compound> res = List.nil();
 923             for (Attribute.TypeCompound a : candidates) {
 924                 if (isCurrentSymbolsAnnotation(a, index))
 925                     res = res.prepend(a);
 926             }
 927 
 928             return res.reverse();
 929         }
 930 
 931         // Helper to getAnnotation[s]
 932         @Override
 933         public <A extends Annotation> Attribute.Compound getAttribute(Class<A> annoType) {
 934             String name = annoType.getName();
 935 
 936             // Declaration annotations on type variables are stored in type attributes
 937             // on the owner of the TypeVariableSymbol
 938             List<Attribute.TypeCompound> candidates = owner.getRawTypeAttributes();
 939             int index = owner.getTypeParameters().indexOf(this);
 940             for (Attribute.TypeCompound anno : candidates)
 941                 if (isCurrentSymbolsAnnotation(anno, index) &&
 942                     name.contentEquals(anno.type.tsym.flatName()))
 943                     return anno;
 944 
 945             return null;
 946         }
 947             //where:
 948             boolean isCurrentSymbolsAnnotation(Attribute.TypeCompound anno, int index) {
 949                 return (anno.position.type == TargetType.CLASS_TYPE_PARAMETER ||
 950                         anno.position.type == TargetType.METHOD_TYPE_PARAMETER) &&
 951                         anno.position.parameter_index == index;
 952             }
 953 
 954 
 955         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 956         public <R, P> R accept(ElementVisitor<R, P> v, P p) {
 957             return v.visitTypeParameter(this, p);
 958         }
 959     }
 960     /** A class for module symbols.
 961      */
 962     public static class ModuleSymbol extends TypeSymbol
 963             implements ModuleElement {
 964 
 965         public Name version;
 966         public JavaFileManager.Location sourceLocation;
 967         public JavaFileManager.Location classLocation;
 968         public JavaFileManager.Location patchLocation;
 969         public JavaFileManager.Location patchOutputLocation;
 970 
 971         /** All directives, in natural order. */
 972         public List<com.sun.tools.javac.code.Directive> directives;
 973         public List<com.sun.tools.javac.code.Directive.RequiresDirective> requires;
 974         public List<com.sun.tools.javac.code.Directive.ExportsDirective> exports;
 975         public List<com.sun.tools.javac.code.Directive.OpensDirective> opens;
 976         public List<com.sun.tools.javac.code.Directive.ProvidesDirective> provides;
 977         public List<com.sun.tools.javac.code.Directive.UsesDirective> uses;
 978 
 979         public ClassSymbol module_info;
 980 
 981         public PackageSymbol unnamedPackage;
 982         public Map<Name, PackageSymbol> visiblePackages;
 983         public Set<ModuleSymbol> readModules;
 984         public List<Symbol> enclosedPackages = List.nil();
 985 
 986         public Completer usesProvidesCompleter = Completer.NULL_COMPLETER;
 987         public final Set<ModuleFlags> flags = EnumSet.noneOf(ModuleFlags.class);
 988         public final Set<ModuleResolutionFlags> resolutionFlags = EnumSet.noneOf(ModuleResolutionFlags.class);
 989 
 990         /**
 991          * Create a ModuleSymbol with an associated module-info ClassSymbol.
 992          */
 993         public static ModuleSymbol create(Name name, Name module_info) {
 994             ModuleSymbol msym = new ModuleSymbol(name, null);
 995             ClassSymbol info = new ClassSymbol(Flags.MODULE, module_info, msym);
 996             info.fullname = formFullName(module_info, msym);
 997             info.flatname = info.fullname;
 998             info.members_field = WriteableScope.create(info);
 999             msym.module_info = info;
1000             return msym;
1001         }
1002 
1003         public ModuleSymbol(Name name, Symbol owner) {
1004             super(MDL, 0, name, null, owner);
1005             Assert.checkNonNull(name);
1006             this.type = new ModuleType(this);
1007         }
1008 
1009         @Override
1010         public int poolTag() {
1011             return ClassFile.CONSTANT_Module;
1012         }
1013 
1014         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1015         public Name getSimpleName() {
1016             return Convert.shortName(name);
1017         }
1018 
1019         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1020         public boolean isOpen() {
1021             return flags.contains(ModuleFlags.OPEN);
1022         }
1023 
1024         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1025         public boolean isUnnamed() {
1026             return name.isEmpty() && owner == null;
1027         }
1028 
1029         @Override
1030         public boolean isDeprecated() {
1031             return hasDeprecatedAnnotation();
1032         }
1033 
1034         public boolean isNoModule() {
1035             return false;
1036         }
1037 
1038         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1039         public ElementKind getKind() {
1040             return ElementKind.MODULE;
1041         }
1042 
1043         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1044         public java.util.List<Directive> getDirectives() {
1045             apiComplete();
1046             completeUsesProvides();
1047             return Collections.unmodifiableList(directives);
1048         }
1049 
1050         public void completeUsesProvides() {
1051             if (usesProvidesCompleter != Completer.NULL_COMPLETER) {
1052                 Completer c = usesProvidesCompleter;
1053                 usesProvidesCompleter = Completer.NULL_COMPLETER;
1054                 c.complete(this);
1055             }
1056         }
1057 
1058         @Override
1059         public ClassSymbol outermostClass() {
1060             return null;
1061         }
1062 
1063         @Override
1064         public String toString() {
1065             // TODO: the following strings should be localized
1066             // Do this with custom anon subtypes in Symtab
1067             String n = (name == null) ? "<unknown>"
1068                     : (name.isEmpty()) ? "<unnamed>"
1069                     : String.valueOf(name);
1070             return n;
1071         }
1072 
1073         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1074         public <R, P> R accept(ElementVisitor<R, P> v, P p) {
1075             return v.visitModule(this, p);
1076         }
1077 
1078         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1079         public List<Symbol> getEnclosedElements() {
1080             List<Symbol> list = List.nil();
1081             for (Symbol sym : enclosedPackages) {
1082                 if (sym.members().anyMatch(m -> m.kind == TYP))
1083                     list = list.prepend(sym);
1084             }
1085             return list;
1086         }
1087 
1088         public void reset() {
1089             this.directives = null;
1090             this.requires = null;
1091             this.exports = null;
1092             this.provides = null;
1093             this.uses = null;
1094             this.visiblePackages = null;
1095         }
1096 
1097     }
1098 
1099     public enum ModuleFlags {
1100         OPEN(0x0020),
1101         SYNTHETIC(0x1000),
1102         MANDATED(0x8000);
1103 
1104         public static int value(Set<ModuleFlags> s) {
1105             int v = 0;
1106             for (ModuleFlags f: s)
1107                 v |= f.value;
1108             return v;
1109         }
1110 
1111         private ModuleFlags(int value) {
1112             this.value = value;
1113         }
1114 
1115         public final int value;
1116     }
1117 
1118     public enum ModuleResolutionFlags {
1119         DO_NOT_RESOLVE_BY_DEFAULT(0x0001),
1120         WARN_DEPRECATED(0x0002),
1121         WARN_DEPRECATED_REMOVAL(0x0004),
1122         WARN_INCUBATING(0x0008);
1123 
1124         public static int value(Set<ModuleResolutionFlags> s) {
1125             int v = 0;
1126             for (ModuleResolutionFlags f: s)
1127                 v |= f.value;
1128             return v;
1129         }
1130 
1131         private ModuleResolutionFlags(int value) {
1132             this.value = value;
1133         }
1134 
1135         public final int value;
1136     }
1137 
1138     /** A class for package symbols
1139      */
1140     public static class PackageSymbol extends TypeSymbol
1141         implements PackageElement {
1142 
1143         public WriteableScope members_field;
1144         public Name fullname;
1145         public ClassSymbol package_info; // see bug 6443073
1146         public ModuleSymbol modle;
1147         // the file containing the documentation comments for the package
1148         public JavaFileObject sourcefile;
1149 
1150         public PackageSymbol(Name name, Type type, Symbol owner) {
1151             super(PCK, 0, name, type, owner);
1152             this.members_field = null;
1153             this.fullname = formFullName(name, owner);
1154         }
1155 
1156         public PackageSymbol(Name name, Symbol owner) {
1157             this(name, null, owner);
1158             this.type = new PackageType(this);
1159         }
1160 
1161         public String toString() {
1162             return fullname.toString();
1163         }
1164 
1165         @DefinedBy(Api.LANGUAGE_MODEL)
1166         public Name getQualifiedName() {
1167             return fullname;
1168         }
1169 
1170         @DefinedBy(Api.LANGUAGE_MODEL)
1171         public boolean isUnnamed() {
1172             return name.isEmpty() && owner != null;
1173         }
1174 
1175         public WriteableScope members() {
1176             complete();
1177             return members_field;
1178         }
1179 
1180         @Override
1181         public int poolTag() {
1182             return ClassFile.CONSTANT_Package;
1183         }
1184 
1185         public long flags() {
1186             complete();
1187             return flags_field;
1188         }
1189 
1190         @Override
1191         public List<Attribute.Compound> getRawAttributes() {
1192             complete();
1193             if (package_info != null) {
1194                 package_info.complete();
1195                 mergeAttributes();
1196             }
1197             return super.getRawAttributes();
1198         }
1199 
1200         private void mergeAttributes() {
1201             if (metadata == null &&
1202                 package_info.metadata != null) {
1203                 metadata = new SymbolMetadata(this);
1204                 metadata.setAttributes(package_info.metadata);
1205             }
1206         }
1207 
1208         /** A package "exists" if a type or package that exists has
1209          *  been seen within it.
1210          */
1211         public boolean exists() {
1212             return (flags_field & EXISTS) != 0;
1213         }
1214 
1215         @DefinedBy(Api.LANGUAGE_MODEL)
1216         public ElementKind getKind() {
1217             return ElementKind.PACKAGE;
1218         }
1219 
1220         @DefinedBy(Api.LANGUAGE_MODEL)
1221         public Symbol getEnclosingElement() {
1222             return modle != null && !modle.isNoModule() ? modle : null;
1223         }
1224 
1225         @DefinedBy(Api.LANGUAGE_MODEL)
1226         public <R, P> R accept(ElementVisitor<R, P> v, P p) {
1227             return v.visitPackage(this, p);
1228         }
1229 
1230         public <R, P> R accept(Symbol.Visitor<R, P> v, P p) {
1231             return v.visitPackageSymbol(this, p);
1232         }
1233 
1234         /**Resets the Symbol into the state good for next round of annotation processing.*/
1235         public void reset() {
1236             metadata = null;
1237         }
1238 
1239     }
1240 
1241     public static class RootPackageSymbol extends PackageSymbol {
1242         public final MissingInfoHandler missingInfoHandler;
1243         public final boolean allowPrivateInvokeVirtual;
1244 
1245         public RootPackageSymbol(Name name, Symbol owner,
1246                                  MissingInfoHandler missingInfoHandler,
1247                                  boolean allowPrivateInvokeVirtual) {
1248             super(name, owner);
1249             this.missingInfoHandler = missingInfoHandler;
1250             this.allowPrivateInvokeVirtual = allowPrivateInvokeVirtual;
1251         }
1252 
1253     }
1254 
1255     /** A class for class symbols
1256      */
1257     public static class ClassSymbol extends TypeSymbol implements TypeElement {
1258 
1259         /** a scope for all class members; variables, methods and inner classes
1260          *  type parameters are not part of this scope
1261          */
1262         public WriteableScope members_field;
1263 
1264         /** the fully qualified name of the class, i.e. pck.outer.inner.
1265          *  null for anonymous classes
1266          */
1267         public Name fullname;
1268 
1269         /** the fully qualified name of the class after converting to flat
1270          *  representation, i.e. pck.outer$inner,
1271          *  set externally for local and anonymous classes
1272          */
1273         public Name flatname;
1274 
1275         /** the sourcefile where the class came from
1276          */
1277         public JavaFileObject sourcefile;
1278 
1279         /** the classfile from where to load this class
1280          *  this will have extension .class or .java
1281          */
1282         public JavaFileObject classfile;
1283 
1284         /** the list of translated local classes (used for generating
1285          * InnerClasses attribute)
1286          */
1287         public List<ClassSymbol> trans_local;
1288 
1289         /** the annotation metadata attached to this class */
1290         private AnnotationTypeMetadata annotationTypeMetadata;
1291 
1292         /* the list of any of record components, only non empty if the class is a record
1293          * and it has at least one record component
1294          */
1295         private List<RecordComponent> recordComponents = List.nil();
1296 
1297         // sealed classes related fields
1298         /** The classes, or interfaces, permitted to extend this class, or interface
1299          */
1300         public List<Symbol> permitted;
1301 
1302         public boolean isPermittedExplicit = false;
1303 
1304         public ClassSymbol(long flags, Name name, Type type, Symbol owner) {
1305             super(TYP, flags, name, type, owner);
1306             this.members_field = null;
1307             this.fullname = formFullName(name, owner);
1308             this.flatname = formFlatName(name, owner);
1309             this.sourcefile = null;
1310             this.classfile = null;
1311             this.annotationTypeMetadata = AnnotationTypeMetadata.notAnAnnotationType();
1312             this.permitted = List.nil();
1313         }
1314 
1315         public ClassSymbol(long flags, Name name, Symbol owner) {
1316             this(
1317                 flags,
1318                 name,
1319                 new ClassType(Type.noType, null, null),
1320                 owner);
1321             this.type.tsym = this;
1322         }
1323 
1324         /** The Java source which this symbol represents.
1325          */
1326         public String toString() {
1327             return className();
1328         }
1329 
1330         public long flags() {
1331             complete();
1332             return flags_field;
1333         }
1334 
1335         public WriteableScope members() {
1336             complete();
1337             return members_field;
1338         }
1339 
1340         @Override
1341         public List<Attribute.Compound> getRawAttributes() {
1342             complete();
1343             return super.getRawAttributes();
1344         }
1345 
1346         @Override
1347         public List<Attribute.TypeCompound> getRawTypeAttributes() {
1348             complete();
1349             return super.getRawTypeAttributes();
1350         }
1351 
1352         public Type erasure(Types types) {
1353             if (erasure_field == null)
1354                 erasure_field = new ClassType(types.erasure(type.getEnclosingType()),
1355                                               List.nil(), this,
1356                                               type.getMetadata());
1357             return erasure_field;
1358         }
1359 
1360         public String className() {
1361             if (name.isEmpty())
1362                 return
1363                     Log.getLocalizedString("anonymous.class", flatname);
1364             else
1365                 return fullname.toString();
1366         }
1367 
1368         @DefinedBy(Api.LANGUAGE_MODEL)
1369         public Name getQualifiedName() {
1370             return fullname;
1371         }
1372 
1373         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1374         public List<Symbol> getEnclosedElements() {
1375             List<Symbol> result = super.getEnclosedElements();
1376             if (!recordComponents.isEmpty()) {
1377                 List<RecordComponent> reversed = recordComponents.reverse();
1378                 for (RecordComponent rc : reversed) {
1379                     result = result.prepend(rc);
1380                 }
1381             }
1382             return result;
1383         }
1384 
1385         public Name flatName() {
1386             return flatname;
1387         }
1388 
1389         public boolean isSubClass(Symbol base, Types types) {
1390             if (this == base) {
1391                 return true;
1392             } else if ((base.flags() & INTERFACE) != 0) {
1393                 for (Type t = type; t.hasTag(CLASS); t = types.supertype(t))
1394                     for (List<Type> is = types.interfaces(t);
1395                          is.nonEmpty();
1396                          is = is.tail)
1397                         if (is.head.tsym.isSubClass(base, types)) return true;
1398             } else {
1399                 for (Type t = type; t.hasTag(CLASS); t = types.supertype(t))
1400                     if (t.tsym == base) return true;
1401             }
1402             return false;
1403         }
1404 
1405         /** Complete the elaboration of this symbol's definition.
1406          */
1407         public void complete() throws CompletionFailure {
1408             Completer origCompleter = completer;
1409             try {
1410                 super.complete();
1411             } catch (CompletionFailure ex) {
1412                 ex.dcfh.classSymbolCompleteFailed(this, origCompleter);
1413                 // quiet error recovery
1414                 flags_field |= (PUBLIC|STATIC);
1415                 this.type = new ErrorType(this, Type.noType);
1416                 throw ex;
1417             }
1418         }
1419 
1420         @DefinedBy(Api.LANGUAGE_MODEL)
1421         public List<Type> getInterfaces() {
1422             apiComplete();
1423             if (type instanceof ClassType classType) {
1424                 if (classType.interfaces_field == null) // FIXME: shouldn't be null
1425                     classType.interfaces_field = List.nil();
1426                 if (classType.all_interfaces_field != null)
1427                     return Type.getModelTypes(classType.all_interfaces_field);
1428                 return classType.interfaces_field;
1429             } else {
1430                 return List.nil();
1431             }
1432         }
1433 
1434         @DefinedBy(Api.LANGUAGE_MODEL)
1435         public Type getSuperclass() {
1436             apiComplete();
1437             if (type instanceof ClassType classType) {
1438                 if (classType.supertype_field == null) // FIXME: shouldn't be null
1439                     classType.supertype_field = Type.noType;
1440                 // An interface has no superclass; its supertype is Object.
1441                 return classType.isInterface()
1442                     ? Type.noType
1443                     : classType.supertype_field.getModelType();
1444             } else {
1445                 return Type.noType;
1446             }
1447         }
1448 
1449         /**
1450          * Returns the next class to search for inherited annotations or {@code null}
1451          * if the next class can't be found.
1452          */
1453         private ClassSymbol getSuperClassToSearchForAnnotations() {
1454 
1455             Type sup = getSuperclass();
1456 
1457             if (!sup.hasTag(CLASS) || sup.isErroneous())
1458                 return null;
1459 
1460             return (ClassSymbol) sup.tsym;
1461         }
1462 
1463 
1464         @Override
1465         protected <A extends Annotation> A[] getInheritedAnnotations(Class<A> annoType) {
1466 
1467             ClassSymbol sup = getSuperClassToSearchForAnnotations();
1468 
1469             return sup == null ? super.getInheritedAnnotations(annoType)
1470                                : sup.getAnnotationsByType(annoType);
1471         }
1472 
1473 
1474         @DefinedBy(Api.LANGUAGE_MODEL)
1475         public ElementKind getKind() {
1476             apiComplete();
1477             long flags = flags();
1478             if ((flags & ANNOTATION) != 0)
1479                 return ElementKind.ANNOTATION_TYPE;
1480             else if ((flags & INTERFACE) != 0)
1481                 return ElementKind.INTERFACE;
1482             else if ((flags & ENUM) != 0)
1483                 return ElementKind.ENUM;
1484             else if ((flags & RECORD) != 0)
1485                 return ElementKind.RECORD;
1486             else
1487                 return ElementKind.CLASS;
1488         }
1489 
1490         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1491         public Set<Modifier> getModifiers() {
1492             apiComplete();
1493             long flags = flags();
1494             return Flags.asModifierSet(flags & ~DEFAULT);
1495         }
1496 
1497         public RecordComponent getRecordComponent(VarSymbol field) {
1498             for (RecordComponent rc : recordComponents) {
1499                 if (rc.name == field.name) {
1500                     return rc;
1501                 }
1502             }
1503             return null;
1504         }
1505 
1506         public RecordComponent getRecordComponent(JCVariableDecl var, boolean addIfMissing, List<JCAnnotation> annotations) {
1507             RecordComponent toRemove = null;
1508             for (RecordComponent rc : recordComponents) {
1509                 /* it could be that a record erroneously declares two record components with the same name, in that
1510                  * case we need to use the position to disambiguate
1511                  */
1512                 if (rc.name == var.name && var.pos == rc.pos) {
1513                     if (rc.type.hasTag(TypeTag.ERROR) && !var.sym.type.hasTag(TypeTag.ERROR)) {
1514                         // Found a record component with an erroneous type: save it so that it can be removed later.
1515                         // If the class type of the record component is generated by annotation processor, it should
1516                         // use the new actual class type and symbol instead of the old dummy ErrorType.
1517                         toRemove = rc;
1518                     } else {
1519                         // Found a good record component: just return.
1520                         return rc;
1521                     }
1522                 }
1523             }
1524             RecordComponent rc = null;
1525             if (toRemove != null) {
1526                 // Found a record component with an erroneous type: remove it and create a new one
1527                 recordComponents = List.filter(recordComponents, toRemove);
1528                 recordComponents = recordComponents.append(rc = new RecordComponent(var.sym, annotations));
1529             } else if (addIfMissing) {
1530                 // Didn't find the record component: create one.
1531                 recordComponents = recordComponents.append(rc = new RecordComponent(var.sym, annotations));
1532             }
1533             return rc;
1534         }
1535 
1536         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1537         public List<? extends RecordComponent> getRecordComponents() {
1538             return recordComponents;
1539         }
1540 
1541         public void setRecordComponents(List<RecordComponent> recordComponents) {
1542             this.recordComponents = recordComponents;
1543         }
1544 
1545         @DefinedBy(Api.LANGUAGE_MODEL)
1546         public NestingKind getNestingKind() {
1547             apiComplete();
1548             if (owner.kind == PCK)
1549                 return NestingKind.TOP_LEVEL;
1550             else if (name.isEmpty())
1551                 return NestingKind.ANONYMOUS;
1552             else if (owner.kind == MTH)
1553                 return NestingKind.LOCAL;
1554             else
1555                 return NestingKind.MEMBER;
1556         }
1557 
1558         @Override
1559         protected <A extends Annotation> Attribute.Compound getAttribute(final Class<A> annoType) {
1560 
1561             Attribute.Compound attrib = super.getAttribute(annoType);
1562 
1563             boolean inherited = annoType.isAnnotationPresent(Inherited.class);
1564             if (attrib != null || !inherited)
1565                 return attrib;
1566 
1567             // Search supertypes
1568             ClassSymbol superType = getSuperClassToSearchForAnnotations();
1569             return superType == null ? null
1570                                      : superType.getAttribute(annoType);
1571         }
1572 
1573         @DefinedBy(Api.LANGUAGE_MODEL)
1574         public <R, P> R accept(ElementVisitor<R, P> v, P p) {
1575             return v.visitType(this, p);
1576         }
1577 
1578         public <R, P> R accept(Symbol.Visitor<R, P> v, P p) {
1579             return v.visitClassSymbol(this, p);
1580         }
1581 
1582         public void markAbstractIfNeeded(Types types) {
1583             if (types.enter.getEnv(this) != null &&
1584                 (flags() & ENUM) != 0 && types.supertype(type).tsym == types.syms.enumSym &&
1585                 (flags() & (FINAL | ABSTRACT)) == 0) {
1586                 if (types.firstUnimplementedAbstract(this) != null)
1587                     // add the ABSTRACT flag to an enum
1588                     flags_field |= ABSTRACT;
1589             }
1590         }
1591 
1592         /**Resets the Symbol into the state good for next round of annotation processing.*/
1593         public void reset() {
1594             kind = TYP;
1595             erasure_field = null;
1596             members_field = null;
1597             flags_field = 0;
1598             if (type instanceof ClassType classType) {
1599                 classType.setEnclosingType(Type.noType);
1600                 classType.rank_field = -1;
1601                 classType.typarams_field = null;
1602                 classType.allparams_field = null;
1603                 classType.supertype_field = null;
1604                 classType.interfaces_field = null;
1605                 classType.all_interfaces_field = null;
1606             }
1607             clearAnnotationMetadata();
1608         }
1609 
1610         public void clearAnnotationMetadata() {
1611             metadata = null;
1612             annotationTypeMetadata = AnnotationTypeMetadata.notAnAnnotationType();
1613         }
1614 
1615         @Override
1616         public AnnotationTypeMetadata getAnnotationTypeMetadata() {
1617             return annotationTypeMetadata;
1618         }
1619 
1620         @Override
1621         public boolean isAnnotationType() {
1622             return (flags_field & Flags.ANNOTATION) != 0;
1623         }
1624 
1625         public void setAnnotationTypeMetadata(AnnotationTypeMetadata a) {
1626             Assert.checkNonNull(a);
1627             Assert.check(!annotationTypeMetadata.isMetadataForAnnotationType());
1628             this.annotationTypeMetadata = a;
1629         }
1630 
1631         public boolean isRecord() {
1632             return (flags_field & RECORD) != 0;
1633         }
1634 
1635         @DefinedBy(Api.LANGUAGE_MODEL)
1636         public List<Type> getPermittedSubclasses() {
1637             return permitted.map(s -> s.type);
1638         }
1639     }
1640 
1641 
1642     /** A class for variable symbols
1643      */
1644     public static class VarSymbol extends Symbol implements VariableElement {
1645 
1646         /** The variable's declaration position.
1647          */
1648         public int pos = Position.NOPOS;
1649 
1650         /** The variable's address. Used for different purposes during
1651          *  flow analysis, translation and code generation.
1652          *  Flow analysis:
1653          *    If this is a blank final or local variable, its sequence number.
1654          *  Translation:
1655          *    If this is a private field, its access number.
1656          *  Code generation:
1657          *    If this is a local variable, its logical slot number.
1658          */
1659         public int adr = -1;
1660 
1661         /** Construct a variable symbol, given its flags, name, type and owner.
1662          */
1663         public VarSymbol(long flags, Name name, Type type, Symbol owner) {
1664             super(VAR, flags, name, type, owner);
1665         }
1666 
1667         @Override
1668         public int poolTag() {
1669             return ClassFile.CONSTANT_Fieldref;
1670         }
1671 
1672         public MethodHandleSymbol asMethodHandle(boolean getter) {
1673             return new MethodHandleSymbol(this, getter);
1674         }
1675 
1676         /** Clone this symbol with new owner.
1677          */
1678         public VarSymbol clone(Symbol newOwner) {
1679             VarSymbol v = new VarSymbol(flags_field, name, type, newOwner) {
1680                 @Override
1681                 public Symbol baseSymbol() {
1682                     return VarSymbol.this;
1683                 }
1684 
1685                 @Override
1686                 public Object poolKey(Types types) {
1687                     return new Pair<>(newOwner, baseSymbol());
1688                 }
1689             };
1690             v.pos = pos;
1691             v.adr = adr;
1692             v.data = data;
1693 //          System.out.println("clone " + v + " in " + newOwner);//DEBUG
1694             return v;
1695         }
1696 
1697         public String toString() {
1698             return name.toString();
1699         }
1700 
1701         public Symbol asMemberOf(Type site, Types types) {
1702             return new VarSymbol(flags_field, name, types.memberType(site, this), owner);
1703         }
1704 
1705         @DefinedBy(Api.LANGUAGE_MODEL)
1706         public ElementKind getKind() {
1707             long flags = flags();
1708             if ((flags & PARAMETER) != 0) {
1709                 if (isExceptionParameter())
1710                     return ElementKind.EXCEPTION_PARAMETER;
1711                 else
1712                     return ElementKind.PARAMETER;
1713             } else if ((flags & ENUM) != 0) {
1714                 return ElementKind.ENUM_CONSTANT;
1715             } else if (owner.kind == TYP || owner.kind == ERR) {
1716                 return ElementKind.FIELD;
1717             } else if (isResourceVariable()) {
1718                 return ElementKind.RESOURCE_VARIABLE;
1719             } else if ((flags & MATCH_BINDING) != 0) {
1720                 ElementKind kind = ElementKind.BINDING_VARIABLE;
1721                 return kind;
1722             } else {
1723                 return ElementKind.LOCAL_VARIABLE;
1724             }
1725         }
1726 
1727         @DefinedBy(Api.LANGUAGE_MODEL)
1728         public <R, P> R accept(ElementVisitor<R, P> v, P p) {
1729             return v.visitVariable(this, p);
1730         }
1731 
1732         @DefinedBy(Api.LANGUAGE_MODEL)
1733         public Object getConstantValue() { // Mirror API
1734             return Constants.decode(getConstValue(), type);
1735         }
1736 
1737         public void setLazyConstValue(final Env<AttrContext> env,
1738                                       final Attr attr,
1739                                       final JCVariableDecl variable)
1740         {
1741             setData((Callable<Object>)() -> attr.attribLazyConstantValue(env, variable, type));
1742         }
1743 
1744         /**
1745          * The variable's constant value, if this is a constant.
1746          * Before the constant value is evaluated, it points to an
1747          * initializer environment.  If this is not a constant, it can
1748          * be used for other stuff.
1749          */
1750         private Object data;
1751 
1752         public boolean isExceptionParameter() {
1753             return data == ElementKind.EXCEPTION_PARAMETER;
1754         }
1755 
1756         public boolean isResourceVariable() {
1757             return data == ElementKind.RESOURCE_VARIABLE;
1758         }
1759 
1760         public Object getConstValue() {
1761             // TODO: Consider if getConstValue and getConstantValue can be collapsed
1762             if (data == ElementKind.EXCEPTION_PARAMETER ||
1763                 data == ElementKind.RESOURCE_VARIABLE) {
1764                 return null;
1765             } else if (data instanceof Callable<?> callableData) {
1766                 // In this case, this is a final variable, with an as
1767                 // yet unevaluated initializer.
1768                 data = null; // to make sure we don't evaluate this twice.
1769                 try {
1770                     data = callableData.call();
1771                 } catch (Exception ex) {
1772                     throw new AssertionError(ex);
1773                 }
1774             }
1775             return data;
1776         }
1777 
1778         public void setData(Object data) {
1779             Assert.check(!(data instanceof Env<?>), this);
1780             this.data = data;
1781         }
1782 
1783         public <R, P> R accept(Symbol.Visitor<R, P> v, P p) {
1784             return v.visitVarSymbol(this, p);
1785         }
1786     }
1787 
1788     public static class RecordComponent extends VarSymbol implements RecordComponentElement {
1789         public MethodSymbol accessor;
1790         public JCTree.JCMethodDecl accessorMeth;
1791         /* the original annotations applied to the record component
1792          */
1793         private final List<JCAnnotation> originalAnnos;
1794         /* if the user happens to erroneously declare two components with the same name, we need a way to differentiate
1795          * them, the code will fail anyway but we need to keep the information for better error recovery
1796          */
1797         private final int pos;
1798 
1799         private final boolean isVarargs;
1800 
1801         /**
1802          * Construct a record component, given its flags, name, type and owner.
1803          */
1804         public RecordComponent(Name name, Type type, Symbol owner) {
1805             super(PUBLIC, name, type, owner);
1806             pos = -1;
1807             originalAnnos = List.nil();
1808             isVarargs = false;
1809         }
1810 
1811         public RecordComponent(VarSymbol field, List<JCAnnotation> annotations) {
1812             super(PUBLIC, field.name, field.type, field.owner);
1813             this.originalAnnos = annotations;
1814             this.pos = field.pos;
1815             /* it is better to store the original information for this one, instead of relying
1816              * on the info in the type of the symbol. This is because on the presence of APs
1817              * the symbol will be blown out and we won't be able to know if the original
1818              * record component was declared varargs or not.
1819              */
1820             this.isVarargs = type.hasTag(TypeTag.ARRAY) && ((ArrayType)type).isVarargs();
1821         }
1822 
1823         public List<JCAnnotation> getOriginalAnnos() { return originalAnnos; }
1824 
1825         public boolean isVarargs() {
1826             return isVarargs;
1827         }
1828 
1829         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1830         public ElementKind getKind() {
1831             return ElementKind.RECORD_COMPONENT;
1832         }
1833 
1834         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1835         public ExecutableElement getAccessor() {
1836             return accessor;
1837         }
1838 
1839         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1840         public <R, P> R accept(ElementVisitor<R, P> v, P p) {
1841             return v.visitRecordComponent(this, p);
1842         }
1843     }
1844 
1845     public static class ParamSymbol extends VarSymbol {
1846         public ParamSymbol(long flags, Name name, Type type, Symbol owner) {
1847             super(flags, name, type, owner);
1848         }
1849 
1850         @Override
1851         public Name getSimpleName() {
1852             if ((flags_field & NAME_FILLED) == 0) {
1853                 flags_field |= NAME_FILLED;
1854                 Symbol rootPack = this;
1855                 while (rootPack != null && !(rootPack instanceof RootPackageSymbol)) {
1856                     rootPack = rootPack.owner;
1857                 }
1858                 if (rootPack != null) {
1859                     Name inferredName =
1860                             ((RootPackageSymbol) rootPack).missingInfoHandler.getParameterName(this);
1861                     if (inferredName != null) {
1862                         this.name = inferredName;
1863                     }
1864                 }
1865             }
1866             return super.getSimpleName();
1867         }
1868 
1869     }
1870 
1871     public static class BindingSymbol extends VarSymbol {
1872 
1873         public BindingSymbol(long flags, Name name, Type type, Symbol owner) {
1874             super(flags | Flags.HASINIT | Flags.MATCH_BINDING, name, type, owner);
1875         }
1876 
1877         public boolean isAliasFor(BindingSymbol b) {
1878             return aliases().containsAll(b.aliases());
1879         }
1880 
1881         List<BindingSymbol> aliases() {
1882             return List.of(this);
1883         }
1884 
1885         public void preserveBinding() {
1886             flags_field |= Flags.MATCH_BINDING_TO_OUTER;
1887         }
1888 
1889         public boolean isPreserved() {
1890             return (flags_field & Flags.MATCH_BINDING_TO_OUTER) != 0;
1891         }
1892     }
1893 
1894     /** A class for method symbols.
1895      */
1896     public static class MethodSymbol extends Symbol implements ExecutableElement {
1897 
1898         /** The code of the method. */
1899         public Code code = null;
1900 
1901         /** The extra (synthetic/mandated) parameters of the method. */
1902         public List<VarSymbol> extraParams = List.nil();
1903 
1904         /** The captured local variables in an anonymous class */
1905         public List<VarSymbol> capturedLocals = List.nil();
1906 
1907         /** The parameters of the method. */
1908         public List<VarSymbol> params = null;
1909 
1910         /** For an annotation type element, its default value if any.
1911          *  The value is null if none appeared in the method
1912          *  declaration.
1913          */
1914         public Attribute defaultValue = null;
1915 
1916         /** Construct a method symbol, given its flags, name, type and owner.
1917          */
1918         public MethodSymbol(long flags, Name name, Type type, Symbol owner) {
1919             super(MTH, flags, name, type, owner);
1920             if (owner.type.hasTag(TYPEVAR)) Assert.error(owner + "." + name);
1921         }
1922 
1923         /** Clone this symbol with new owner.
1924          */
1925         public MethodSymbol clone(Symbol newOwner) {
1926             MethodSymbol m = new MethodSymbol(flags_field, name, type, newOwner) {
1927                 @Override
1928                 public Symbol baseSymbol() {
1929                     return MethodSymbol.this;
1930                 }
1931 
1932                 @Override
1933                 public Object poolKey(Types types) {
1934                     return new Pair<>(newOwner, baseSymbol());
1935                 }
1936             };
1937             m.code = code;
1938             return m;
1939         }
1940 
1941         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1942         public Set<Modifier> getModifiers() {
1943             long flags = flags();
1944             return Flags.asModifierSet((flags & DEFAULT) != 0 ? flags & ~ABSTRACT : flags);
1945         }
1946 
1947         /** The Java source which this symbol represents.
1948          */
1949         public String toString() {
1950             if ((flags() & BLOCK) != 0) {
1951                 return owner.name.toString();
1952             } else {
1953                 String s = (name == name.table.names.init)
1954                     ? owner.name.toString()
1955                     : name.toString();
1956                 if (type != null) {
1957                     if (type.hasTag(FORALL))
1958                         s = "<" + ((ForAll)type).getTypeArguments() + ">" + s;
1959                     s += "(" + type.argtypes((flags() & VARARGS) != 0) + ")";
1960                 }
1961                 return s;
1962             }
1963         }
1964 
1965         @Override
1966         public int poolTag() {
1967             return owner.isInterface() ?
1968                     ClassFile.CONSTANT_InterfaceMethodref : ClassFile.CONSTANT_Methodref;
1969         }
1970 
1971         public boolean isHandle() {
1972             return false;
1973         }
1974 
1975 
1976         public MethodHandleSymbol asHandle() {
1977             return new MethodHandleSymbol(this);
1978         }
1979 
1980         /** find a symbol that this (proxy method) symbol implements.
1981          *  @param    c       The class whose members are searched for
1982          *                    implementations
1983          */
1984         public Symbol implemented(TypeSymbol c, Types types) {
1985             Symbol impl = null;
1986             for (List<Type> is = types.interfaces(c.type);
1987                  impl == null && is.nonEmpty();
1988                  is = is.tail) {
1989                 TypeSymbol i = is.head.tsym;
1990                 impl = implementedIn(i, types);
1991                 if (impl == null)
1992                     impl = implemented(i, types);
1993             }
1994             return impl;
1995         }
1996 
1997         public Symbol implementedIn(TypeSymbol c, Types types) {
1998             Symbol impl = null;
1999             for (Symbol sym : c.members().getSymbolsByName(name)) {
2000                 if (this.overrides(sym, (TypeSymbol)owner, types, true) &&
2001                     // FIXME: I suspect the following requires a
2002                     // subst() for a parametric return type.
2003                     types.isSameType(type.getReturnType(),
2004                                      types.memberType(owner.type, sym).getReturnType())) {
2005                     impl = sym;
2006                 }
2007             }
2008             return impl;
2009         }
2010 
2011         /** Will the erasure of this method be considered by the VM to
2012          *  override the erasure of the other when seen from class `origin'?
2013          */
2014         public boolean binaryOverrides(Symbol _other, TypeSymbol origin, Types types) {
2015             if (isConstructor() || _other.kind != MTH) return false;
2016 
2017             if (this == _other) return true;
2018             MethodSymbol other = (MethodSymbol)_other;
2019 
2020             // check for a direct implementation
2021             if (other.isOverridableIn((TypeSymbol)owner) &&
2022                 types.asSuper(owner.type, other.owner) != null &&
2023                 types.isSameType(erasure(types), other.erasure(types)))
2024                 return true;
2025 
2026             // check for an inherited implementation
2027             return
2028                 (flags() & ABSTRACT) == 0 &&
2029                 other.isOverridableIn(origin) &&
2030                 this.isMemberOf(origin, types) &&
2031                 types.isSameType(erasure(types), other.erasure(types));
2032         }
2033 
2034         /** The implementation of this (abstract) symbol in class origin,
2035          *  from the VM's point of view, null if method does not have an
2036          *  implementation in class.
2037          *  @param origin   The class of which the implementation is a member.
2038          */
2039         public MethodSymbol binaryImplementation(ClassSymbol origin, Types types) {
2040             for (TypeSymbol c = origin; c != null; c = types.supertype(c.type).tsym) {
2041                 for (Symbol sym : c.members().getSymbolsByName(name)) {
2042                     if (sym.kind == MTH &&
2043                         ((MethodSymbol)sym).binaryOverrides(this, origin, types))
2044                         return (MethodSymbol)sym;
2045                 }
2046             }
2047             return null;
2048         }
2049 
2050         /** Does this symbol override `other' symbol, when both are seen as
2051          *  members of class `origin'?  It is assumed that _other is a member
2052          *  of origin.
2053          *
2054          *  It is assumed that both symbols have the same name.  The static
2055          *  modifier is ignored for this test.
2056          *
2057          *  A quirk in the works is that if the receiver is a method symbol for
2058          *  an inherited abstract method we answer false summarily all else being
2059          *  immaterial. Abstract "own" methods (i.e `this' is a direct member of
2060          *  origin) don't get rejected as summarily and are put to test against the
2061          *  suitable criteria.
2062          *
2063          *  See JLS 8.4.6.1 (without transitivity) and 8.4.6.4
2064          */
2065         public boolean overrides(Symbol _other, TypeSymbol origin, Types types, boolean checkResult) {
2066             return overrides(_other, origin, types, checkResult, true);
2067         }
2068 
2069         /** Does this symbol override `other' symbol, when both are seen as
2070          *  members of class `origin'?  It is assumed that _other is a member
2071          *  of origin.
2072          *
2073          *  Caveat: If `this' is an abstract inherited member of origin, it is
2074          *  deemed to override `other' only when `requireConcreteIfInherited'
2075          *  is false.
2076          *
2077          *  It is assumed that both symbols have the same name.  The static
2078          *  modifier is ignored for this test.
2079          *
2080          *  See JLS 8.4.6.1 (without transitivity) and 8.4.6.4
2081          */
2082         public boolean overrides(Symbol _other, TypeSymbol origin, Types types, boolean checkResult,
2083                                             boolean requireConcreteIfInherited) {
2084             if (isConstructor() || _other.kind != MTH) return false;
2085 
2086             if (this == _other) return true;
2087             MethodSymbol other = (MethodSymbol)_other;
2088 
2089             // check for a direct implementation
2090             if (other.isOverridableIn((TypeSymbol)owner) &&
2091                 types.asSuper(owner.type, other.owner) != null) {
2092                 Type mt = types.memberType(owner.type, this);
2093                 Type ot = types.memberType(owner.type, other);
2094                 if (types.isSubSignature(mt, ot)) {
2095                     if (!checkResult)
2096                         return true;
2097                     if (types.returnTypeSubstitutable(mt, ot))
2098                         return true;
2099                 }
2100             }
2101 
2102             // check for an inherited implementation
2103             if (((flags() & ABSTRACT) != 0 && requireConcreteIfInherited) ||
2104                     ((other.flags() & ABSTRACT) == 0 && (other.flags() & DEFAULT) == 0) ||
2105                     !other.isOverridableIn(origin) ||
2106                     !this.isMemberOf(origin, types))
2107                 return false;
2108 
2109             // assert types.asSuper(origin.type, other.owner) != null;
2110             Type mt = types.memberType(origin.type, this);
2111             Type ot = types.memberType(origin.type, other);
2112             return
2113                 types.isSubSignature(mt, ot) &&
2114                 (!checkResult || types.resultSubtype(mt, ot, types.noWarnings));
2115         }
2116 
2117         private boolean isOverridableIn(TypeSymbol origin) {
2118             // JLS 8.4.6.1
2119             switch ((int)(flags_field & Flags.AccessFlags)) {
2120             case Flags.PRIVATE:
2121                 return false;
2122             case Flags.PUBLIC:
2123                 return !this.owner.isInterface() ||
2124                         (flags_field & STATIC) == 0;
2125             case Flags.PROTECTED:
2126                 return (origin.flags() & INTERFACE) == 0;
2127             case 0:
2128                 // for package private: can only override in the same
2129                 // package
2130                 return
2131                     this.packge() == origin.packge() &&
2132                     (origin.flags() & INTERFACE) == 0;
2133             default:
2134                 return false;
2135             }
2136         }
2137 
2138         @Override
2139         public boolean isInheritedIn(Symbol clazz, Types types) {
2140             switch ((int)(flags_field & Flags.AccessFlags)) {
2141                 case PUBLIC:
2142                     return !this.owner.isInterface() ||
2143                             clazz == owner ||
2144                             (flags_field & STATIC) == 0;
2145                 default:
2146                     return super.isInheritedIn(clazz, types);
2147             }
2148         }
2149 
2150         public boolean isLambdaMethod() {
2151             return (flags() & LAMBDA_METHOD) == LAMBDA_METHOD;
2152         }
2153 
2154         /** override this method to point to the original enclosing method if this method symbol represents a synthetic
2155          *  lambda method
2156          */
2157         public MethodSymbol originalEnclosingMethod() {
2158             return this;
2159         }
2160 
2161         /** The implementation of this (abstract) symbol in class origin;
2162          *  null if none exists. Synthetic methods are not considered
2163          *  as possible implementations.
2164          */
2165         public MethodSymbol implementation(TypeSymbol origin, Types types, boolean checkResult) {
2166             return implementation(origin, types, checkResult, implementation_filter);
2167         }
2168         // where
2169             public static final Predicate<Symbol> implementation_filter = s ->
2170                     s.kind == MTH && (s.flags() & SYNTHETIC) == 0;
2171 
2172         public MethodSymbol implementation(TypeSymbol origin, Types types, boolean checkResult, Predicate<Symbol> implFilter) {
2173             MethodSymbol res = types.implementation(this, origin, checkResult, implFilter);
2174             if (res != null)
2175                 return res;
2176             // if origin is derived from a raw type, we might have missed
2177             // an implementation because we do not know enough about instantiations.
2178             // in this case continue with the supertype as origin.
2179             if (types.isDerivedRaw(origin.type) && !origin.isInterface())
2180                 return implementation(types.supertype(origin.type).tsym, types, checkResult);
2181             else
2182                 return null;
2183         }
2184 
2185         public List<VarSymbol> params() {
2186             owner.complete();
2187             if (params == null) {
2188                 ListBuffer<VarSymbol> newParams = new ListBuffer<>();
2189                 int i = 0;
2190                 for (Type t : type.getParameterTypes()) {
2191                     Name paramName = name.table.fromString("arg" + i);
2192                     VarSymbol param = new VarSymbol(PARAMETER, paramName, t, this);
2193                     newParams.append(param);
2194                     i++;
2195                 }
2196                 params = newParams.toList();
2197             }
2198             Assert.checkNonNull(params);
2199             return params;
2200         }
2201 
2202         public Symbol asMemberOf(Type site, Types types) {
2203             return new MethodSymbol(flags_field, name, types.memberType(site, this), owner);
2204         }
2205 
2206         @DefinedBy(Api.LANGUAGE_MODEL)
2207         public ElementKind getKind() {
2208             if (name == name.table.names.init)
2209                 return ElementKind.CONSTRUCTOR;
2210             else if (name == name.table.names.clinit)
2211                 return ElementKind.STATIC_INIT;
2212             else if ((flags() & BLOCK) != 0)
2213                 return isStatic() ? ElementKind.STATIC_INIT : ElementKind.INSTANCE_INIT;
2214             else
2215                 return ElementKind.METHOD;
2216         }
2217 
2218         public boolean isStaticOrInstanceInit() {
2219             return getKind() == ElementKind.STATIC_INIT ||
2220                     getKind() == ElementKind.INSTANCE_INIT;
2221         }
2222 
2223         @DefinedBy(Api.LANGUAGE_MODEL)
2224         public Attribute getDefaultValue() {
2225             return defaultValue;
2226         }
2227 
2228         @DefinedBy(Api.LANGUAGE_MODEL)
2229         public List<VarSymbol> getParameters() {
2230             return params();
2231         }
2232 
2233         @DefinedBy(Api.LANGUAGE_MODEL)
2234         public boolean isVarArgs() {
2235             return (flags() & VARARGS) != 0;
2236         }
2237 
2238         @DefinedBy(Api.LANGUAGE_MODEL)
2239         public boolean isDefault() {
2240             return (flags() & DEFAULT) != 0;
2241         }
2242 
2243         @DefinedBy(Api.LANGUAGE_MODEL)
2244         public <R, P> R accept(ElementVisitor<R, P> v, P p) {
2245             return v.visitExecutable(this, p);
2246         }
2247 
2248         public <R, P> R accept(Symbol.Visitor<R, P> v, P p) {
2249             return v.visitMethodSymbol(this, p);
2250         }
2251 
2252         @DefinedBy(Api.LANGUAGE_MODEL)
2253         public Type getReceiverType() {
2254             return asType().getReceiverType();
2255         }
2256 
2257         @DefinedBy(Api.LANGUAGE_MODEL)
2258         public Type getReturnType() {
2259             return asType().getReturnType();
2260         }
2261 
2262         @DefinedBy(Api.LANGUAGE_MODEL)
2263         public List<Type> getThrownTypes() {
2264             return asType().getThrownTypes();
2265         }
2266     }
2267 
2268     /** A class for invokedynamic method calls.
2269      */
2270     public static class DynamicMethodSymbol extends MethodSymbol implements Dynamic {
2271 
2272         public LoadableConstant[] staticArgs;
2273         public MethodHandleSymbol bsm;
2274 
2275         public DynamicMethodSymbol(Name name, Symbol owner, MethodHandleSymbol bsm, Type type, LoadableConstant[] staticArgs) {
2276             super(0, name, type, owner);
2277             this.bsm = bsm;
2278             this.staticArgs = staticArgs;
2279         }
2280 
2281         @Override
2282         public boolean isDynamic() {
2283             return true;
2284         }
2285 
2286         @Override
2287         public LoadableConstant[] staticArgs() {
2288             return staticArgs;
2289         }
2290 
2291         @Override
2292         public MethodHandleSymbol bootstrapMethod() {
2293             return bsm;
2294         }
2295 
2296         @Override
2297         public int poolTag() {
2298             return ClassFile.CONSTANT_InvokeDynamic;
2299         }
2300 
2301         @Override
2302         public Type dynamicType() {
2303             return type;
2304         }
2305     }
2306 
2307     /** A class for condy.
2308      */
2309     public static class DynamicVarSymbol extends VarSymbol implements Dynamic, LoadableConstant {
2310         public LoadableConstant[] staticArgs;
2311         public MethodHandleSymbol bsm;
2312 
2313         public DynamicVarSymbol(Name name, Symbol owner, MethodHandleSymbol bsm, Type type, LoadableConstant[] staticArgs) {
2314             super(0, name, type, owner);
2315             this.bsm = bsm;
2316             this.staticArgs = staticArgs;
2317         }
2318 
2319         @Override
2320         public boolean isDynamic() {
2321             return true;
2322         }
2323 
2324         @Override
2325         public PoolConstant dynamicType() {
2326             return type;
2327         }
2328 
2329         @Override
2330         public LoadableConstant[] staticArgs() {
2331             return staticArgs;
2332         }
2333 
2334         @Override
2335         public LoadableConstant bootstrapMethod() {
2336             return bsm;
2337         }
2338 
2339         @Override
2340         public int poolTag() {
2341             return ClassFile.CONSTANT_Dynamic;
2342         }
2343     }
2344 
2345     /** A class for method handles.
2346      */
2347     public static class MethodHandleSymbol extends MethodSymbol implements LoadableConstant {
2348 
2349         private Symbol refSym;
2350         private boolean getter;
2351 
2352         public MethodHandleSymbol(Symbol msym) {
2353             this(msym, false);
2354         }
2355 
2356         public MethodHandleSymbol(Symbol msym, boolean getter) {
2357             super(msym.flags_field, msym.name, msym.type, msym.owner);
2358             this.refSym = msym;
2359             this.getter = getter;
2360         }
2361 
2362         /**
2363          * Returns the kind associated with this method handle.
2364          */
2365         public int referenceKind() {
2366             if (refSym.kind == VAR) {
2367                 return getter ?
2368                         refSym.isStatic() ? ClassFile.REF_getStatic : ClassFile.REF_getField :
2369                         refSym.isStatic() ? ClassFile.REF_putStatic : ClassFile.REF_putField;
2370             } else {
2371                 if (refSym.isConstructor()) {
2372                     return ClassFile.REF_newInvokeSpecial;
2373                 } else {
2374                     if (refSym.isStatic()) {
2375                         return ClassFile.REF_invokeStatic;
2376                     } else if ((refSym.flags() & PRIVATE) != 0 && !allowPrivateInvokeVirtual()) {
2377                         return ClassFile.REF_invokeSpecial;
2378                     } else if (refSym.enclClass().isInterface()) {
2379                         return ClassFile.REF_invokeInterface;
2380                     } else {
2381                         return ClassFile.REF_invokeVirtual;
2382                     }
2383                 }
2384             }
2385         }
2386 
2387         private boolean allowPrivateInvokeVirtual() {
2388             Symbol rootPack = this;
2389             while (rootPack != null && !(rootPack instanceof RootPackageSymbol)) {
2390                 rootPack = rootPack.owner;
2391             }
2392             return rootPack != null && ((RootPackageSymbol) rootPack).allowPrivateInvokeVirtual;
2393         }
2394         @Override
2395         public int poolTag() {
2396             return ClassFile.CONSTANT_MethodHandle;
2397         }
2398 
2399         @Override
2400         public Object poolKey(Types types) {
2401             return new Pair<>(baseSymbol(), referenceKind());
2402         }
2403 
2404         @Override
2405         public MethodHandleSymbol asHandle() {
2406             return this;
2407         }
2408 
2409         @Override
2410         public Symbol baseSymbol() {
2411             return refSym;
2412         }
2413 
2414 
2415         @Override
2416         public boolean isHandle() {
2417             return true;
2418         }
2419     }
2420 
2421     /** A class for predefined operators.
2422      */
2423     public static class OperatorSymbol extends MethodSymbol {
2424 
2425         public int opcode;
2426         private int accessCode = Integer.MIN_VALUE;
2427 
2428         public OperatorSymbol(Name name, Type type, int opcode, Symbol owner) {
2429             super(PUBLIC | STATIC, name, type, owner);
2430             this.opcode = opcode;
2431         }
2432 
2433         @Override
2434         public <R, P> R accept(Symbol.Visitor<R, P> v, P p) {
2435             return v.visitOperatorSymbol(this, p);
2436         }
2437 
2438         public int getAccessCode(Tag tag) {
2439             if (accessCode != Integer.MIN_VALUE && !tag.isIncOrDecUnaryOp()) {
2440                 return accessCode;
2441             }
2442             accessCode = AccessCode.from(tag, opcode);
2443             return accessCode;
2444         }
2445 
2446         /** Access codes for dereferencing, assignment,
2447          *  and pre/post increment/decrement.
2448 
2449          *  All access codes for accesses to the current class are even.
2450          *  If a member of the superclass should be accessed instead (because
2451          *  access was via a qualified super), add one to the corresponding code
2452          *  for the current class, making the number odd.
2453          *  This numbering scheme is used by the backend to decide whether
2454          *  to issue an invokevirtual or invokespecial call.
2455          *
2456          *  @see Gen#visitSelect(JCFieldAccess tree)
2457          */
2458         public enum AccessCode {
2459             UNKNOWN(-1, Tag.NO_TAG),
2460             DEREF(0, Tag.NO_TAG),
2461             ASSIGN(2, Tag.ASSIGN),
2462             PREINC(4, Tag.PREINC),
2463             PREDEC(6, Tag.PREDEC),
2464             POSTINC(8, Tag.POSTINC),
2465             POSTDEC(10, Tag.POSTDEC),
2466             FIRSTASGOP(12, Tag.NO_TAG);
2467 
2468             public final int code;
2469             public final Tag tag;
2470             public static final int numberOfAccessCodes = (lushrl - ishll + lxor + 2 - iadd) * 2 + FIRSTASGOP.code + 2;
2471 
2472             AccessCode(int code, Tag tag) {
2473                 this.code = code;
2474                 this.tag = tag;
2475             }
2476 
2477             public static AccessCode getFromCode(int code) {
2478                 for (AccessCode aCodes : AccessCode.values()) {
2479                     if (aCodes.code == code) {
2480                         return aCodes;
2481                     }
2482                 }
2483                 return UNKNOWN;
2484             }
2485 
2486             static int from(Tag tag, int opcode) {
2487                 /** Map bytecode of binary operation to access code of corresponding
2488                 *  assignment operation. This is always an even number.
2489                 */
2490                 switch (tag) {
2491                     case PREINC:
2492                         return AccessCode.PREINC.code;
2493                     case PREDEC:
2494                         return AccessCode.PREDEC.code;
2495                     case POSTINC:
2496                         return AccessCode.POSTINC.code;
2497                     case POSTDEC:
2498                         return AccessCode.POSTDEC.code;
2499                 }
2500                 if (iadd <= opcode && opcode <= lxor) {
2501                     return (opcode - iadd) * 2 + FIRSTASGOP.code;
2502                 } else if (opcode == string_add) {
2503                     return (lxor + 1 - iadd) * 2 + FIRSTASGOP.code;
2504                 } else if (ishll <= opcode && opcode <= lushrl) {
2505                     return (opcode - ishll + lxor + 2 - iadd) * 2 + FIRSTASGOP.code;
2506                 }
2507                 return -1;
2508             }
2509         }
2510     }
2511 
2512     /** Symbol completer interface.
2513      */
2514     public static interface Completer {
2515 
2516         /** Dummy completer to be used when the symbol has been completed or
2517          * does not need completion.
2518          */
2519         public static final Completer NULL_COMPLETER = new Completer() {
2520             public void complete(Symbol sym) { }
2521             public boolean isTerminal() { return true; }
2522         };
2523 
2524         void complete(Symbol sym) throws CompletionFailure;
2525 
2526         /** Returns true if this completer is <em>terminal</em>. A terminal
2527          * completer is used as a place holder when the symbol is completed.
2528          * Calling complete on a terminal completer will not affect the symbol.
2529          *
2530          * The dummy NULL_COMPLETER and the GraphDependencies completer are
2531          * examples of terminal completers.
2532          *
2533          * @return true iff this completer is terminal
2534          */
2535         default boolean isTerminal() {
2536             return false;
2537         }
2538     }
2539 
2540     public static class CompletionFailure extends RuntimeException {
2541         private static final long serialVersionUID = 0;
2542         public final transient DeferredCompletionFailureHandler dcfh;
2543         public transient Symbol sym;
2544 
2545         /** A diagnostic object describing the failure
2546          */
2547         private transient JCDiagnostic diag;
2548 
2549         private transient Supplier<JCDiagnostic> diagSupplier;
2550 
2551         public CompletionFailure(Symbol sym, Supplier<JCDiagnostic> diagSupplier, DeferredCompletionFailureHandler dcfh) {
2552             this.dcfh = dcfh;
2553             this.sym = sym;
2554             this.diagSupplier = diagSupplier;
2555 //          this.printStackTrace();//DEBUG
2556         }
2557 
2558         public JCDiagnostic getDiagnostic() {
2559             if (diag == null && diagSupplier != null) {
2560                 diag = diagSupplier.get();
2561             }
2562             return diag;
2563         }
2564 
2565         @Override
2566         public String getMessage() {
2567             return getDiagnostic().getMessage(null);
2568         }
2569 
2570         public JCDiagnostic getDetailValue() {
2571             return getDiagnostic();
2572         }
2573 
2574         @Override
2575         public CompletionFailure initCause(Throwable cause) {
2576             super.initCause(cause);
2577             return this;
2578         }
2579 
2580         public void resetDiagnostic(Supplier<JCDiagnostic> diagSupplier) {
2581             this.diagSupplier = diagSupplier;
2582             this.diag = null;
2583         }
2584 
2585     }
2586 
2587     /**
2588      * A visitor for symbols.  A visitor is used to implement operations
2589      * (or relations) on symbols.  Most common operations on types are
2590      * binary relations and this interface is designed for binary
2591      * relations, that is, operations on the form
2592      * Symbol&nbsp;&times;&nbsp;P&nbsp;&rarr;&nbsp;R.
2593      * <!-- In plain text: Type x P -> R -->
2594      *
2595      * @param <R> the return type of the operation implemented by this
2596      * visitor; use Void if no return type is needed.
2597      * @param <P> the type of the second argument (the first being the
2598      * symbol itself) of the operation implemented by this visitor; use
2599      * Void if a second argument is not needed.
2600      */
2601     public interface Visitor<R,P> {
2602         R visitClassSymbol(ClassSymbol s, P arg);
2603         R visitMethodSymbol(MethodSymbol s, P arg);
2604         R visitPackageSymbol(PackageSymbol s, P arg);
2605         R visitOperatorSymbol(OperatorSymbol s, P arg);
2606         R visitVarSymbol(VarSymbol s, P arg);
2607         R visitTypeSymbol(TypeSymbol s, P arg);
2608         R visitSymbol(Symbol s, P arg);
2609     }
2610 }