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