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