1 /*
   2  * Copyright (c) 1999, 2024, 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.util.ArrayDeque;
  30 import java.util.Collections;
  31 import java.util.EnumMap;
  32 import java.util.Map;
  33 import java.util.Optional;
  34 import java.util.function.Function;
  35 import java.util.function.Predicate;
  36 
  37 import javax.lang.model.type.*;
  38 
  39 import com.sun.tools.javac.code.Symbol.*;
  40 import com.sun.tools.javac.code.TypeMetadata.Annotations;
  41 import com.sun.tools.javac.code.TypeMetadata.ConstantValue;
  42 import com.sun.tools.javac.code.Types.TypeMapping;
  43 import com.sun.tools.javac.code.Types.UniqueType;
  44 import com.sun.tools.javac.comp.Infer.IncorporationAction;
  45 import com.sun.tools.javac.jvm.ClassFile;
  46 import com.sun.tools.javac.jvm.PoolConstant;
  47 import com.sun.tools.javac.util.*;
  48 import com.sun.tools.javac.util.DefinedBy.Api;
  49 
  50 import static com.sun.tools.javac.code.BoundKind.*;
  51 import static com.sun.tools.javac.code.Flags.*;
  52 import static com.sun.tools.javac.code.Kinds.Kind.*;
  53 import static com.sun.tools.javac.code.TypeTag.*;
  54 
  55 /** This class represents Java types. The class itself defines the behavior of
  56  *  the following types:
  57  *  <pre>
  58  *  base types (tags: BYTE, CHAR, SHORT, INT, LONG, FLOAT, DOUBLE, BOOLEAN),
  59  *  type `void' (tag: VOID),
  60  *  the bottom type (tag: BOT),
  61  *  the missing type (tag: NONE).
  62  *  </pre>
  63  *  <p>The behavior of the following types is defined in subclasses, which are
  64  *  all static inner classes of this class:
  65  *  <pre>
  66  *  class types (tag: CLASS, class: ClassType),
  67  *  array types (tag: ARRAY, class: ArrayType),
  68  *  method types (tag: METHOD, class: MethodType),
  69  *  package types (tag: PACKAGE, class: PackageType),
  70  *  type variables (tag: TYPEVAR, class: TypeVar),
  71  *  type arguments (tag: WILDCARD, class: WildcardType),
  72  *  generic method types (tag: FORALL, class: ForAll),
  73  *  the error type (tag: ERROR, class: ErrorType).
  74  *  </pre>
  75  *
  76  *  <p><b>This is NOT part of any supported API.
  77  *  If you write code that depends on this, you do so at your own risk.
  78  *  This code and its internal interfaces are subject to change or
  79  *  deletion without notice.</b>
  80  *
  81  *  @see TypeTag
  82  */
  83 public abstract class Type extends AnnoConstruct implements TypeMirror, PoolConstant {
  84 
  85     /**
  86      * Type metadata,  Should be {@code null} for the default value.
  87      *
  88      * Note: it is an invariant that for any {@code TypeMetadata}
  89      * class, a given {@code Type} may have at most one metadata array
  90      * entry of that class.
  91      */
  92     protected final List<TypeMetadata> metadata;
  93 
  94     /** Constant type: no type at all. */
  95     public static final JCNoType noType = new JCNoType() {
  96         @Override @DefinedBy(Api.LANGUAGE_MODEL)
  97         public String toString() {
  98             return "none";
  99         }
 100     };
 101 
 102     /** Constant type: special type to be used during recovery of deferred expressions. */
 103     public static final JCNoType recoveryType = new JCNoType(){
 104         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 105         public String toString() {
 106             return "recovery";
 107         }
 108     };
 109 
 110     /** Constant type: special type to be used for marking stuck trees. */
 111     public static final JCNoType stuckType = new JCNoType() {
 112         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 113         public String toString() {
 114             return "stuck";
 115         }
 116     };
 117 
 118     /** If this switch is turned on, the names of type variables
 119      *  and anonymous classes are printed with hashcodes appended.
 120      */
 121     public static boolean moreInfo = false;
 122 
 123     /** The defining class / interface / package / type variable.
 124      */
 125     public TypeSymbol tsym;
 126 
 127     @Override
 128     public int poolTag() {
 129         throw new AssertionError("Invalid pool entry");
 130     }
 131 
 132     @Override
 133     public Object poolKey(Types types) {
 134         return new UniqueType(this, types);
 135     }
 136 
 137     /**
 138      * Checks if the current type tag is equal to the given tag.
 139      * @return true if tag is equal to the current type tag.
 140      */
 141     public boolean hasTag(TypeTag tag) {
 142         return tag == getTag();
 143     }
 144 
 145     /**
 146      * Returns the current type tag.
 147      * @return the value of the current type tag.
 148      */
 149     public abstract TypeTag getTag();
 150 
 151     public boolean isNumeric() {
 152         return false;
 153     }
 154 
 155     public boolean isIntegral() {
 156         return false;
 157     }
 158 
 159     public boolean isPrimitive() {
 160         return false;
 161     }
 162 
 163     public boolean isPrimitiveOrVoid() {
 164         return false;
 165     }
 166 
 167     public boolean isReference() {
 168         return false;
 169     }
 170 
 171     public boolean isNullOrReference() {
 172         return false;
 173     }
 174 
 175     public boolean isPartial() {
 176         return false;
 177     }
 178 
 179     /**
 180      * The constant value of this type, null if this type does not
 181      * have a constant value attribute. Only primitive types and
 182      * strings (ClassType) can have a constant value attribute.
 183      * @return the constant value attribute of this type
 184      */
 185     public Object constValue() {
 186         return getMetadata(TypeMetadata.ConstantValue.class, ConstantValue::value, null);
 187     }
 188 
 189     /** Is this a constant type whose value is false?
 190      */
 191     public boolean isFalse() {
 192         return false;
 193     }
 194 
 195     /** Is this a constant type whose value is true?
 196      */
 197     public boolean isTrue() {
 198         return false;
 199     }
 200 
 201     /**
 202      * Get the representation of this type used for modelling purposes.
 203      * By default, this is itself. For ErrorType, a different value
 204      * may be provided.
 205      */
 206     public Type getModelType() {
 207         return this;
 208     }
 209 
 210     public static List<Type> getModelTypes(List<Type> ts) {
 211         ListBuffer<Type> lb = new ListBuffer<>();
 212         for (Type t: ts)
 213             lb.append(t.getModelType());
 214         return lb.toList();
 215     }
 216 
 217     /**For ErrorType, returns the original type, otherwise returns the type itself.
 218      */
 219     public Type getOriginalType() {
 220         return this;
 221     }
 222 
 223     public <R,S> R accept(Type.Visitor<R,S> v, S s) { return v.visitType(this, s); }
 224 
 225     /** Define a type given its tag, type symbol, and type annotations
 226      */
 227 
 228     public Type(TypeSymbol tsym, List<TypeMetadata> metadata) {
 229         Assert.checkNonNull(metadata);
 230         this.tsym = tsym;
 231         this.metadata = metadata;
 232     }
 233 
 234     /**
 235      * A subclass of {@link Types.TypeMapping} which applies a mapping recursively to the subterms
 236      * of a given type expression. This mapping returns the original type is no changes occurred
 237      * when recursively mapping the original type's subterms.
 238      */
 239     public abstract static class StructuralTypeMapping<S> extends Types.TypeMapping<S> {
 240 
 241         @Override
 242         public Type visitClassType(ClassType t, S s) {
 243             Type outer = t.getEnclosingType();
 244             Type outer1 = visit(outer, s);
 245             List<Type> typarams = t.getTypeArguments();
 246             List<Type> typarams1 = visit(typarams, s);
 247             if (outer1 == outer && typarams1 == typarams) return t;
 248             else return new ClassType(outer1, typarams1, t.tsym, t.metadata) {
 249                 @Override
 250                 protected boolean needsStripping() {
 251                     return true;
 252                 }
 253             };
 254         }
 255 
 256         @Override
 257         public Type visitWildcardType(WildcardType wt, S s) {
 258             Type t = wt.type;
 259             if (t != null)
 260                 t = visit(t, s);
 261             if (t == wt.type)
 262                 return wt;
 263             else
 264                 return new WildcardType(t, wt.kind, wt.tsym, wt.bound, wt.metadata) {
 265                     @Override
 266                     protected boolean needsStripping() {
 267                         return true;
 268                     }
 269                 };
 270         }
 271 
 272         @Override
 273         public Type visitArrayType(ArrayType t, S s) {
 274             Type elemtype = t.elemtype;
 275             Type elemtype1 = visit(elemtype, s);
 276             if (elemtype1 == elemtype) return t;
 277             else return new ArrayType(elemtype1, t.tsym, t.metadata) {
 278                 @Override
 279                 protected boolean needsStripping() {
 280                     return true;
 281                 }
 282             };
 283         }
 284 
 285         @Override
 286         public Type visitMethodType(MethodType t, S s) {
 287             List<Type> argtypes = t.argtypes;
 288             Type restype = t.restype;
 289             List<Type> thrown = t.thrown;
 290             List<Type> argtypes1 = visit(argtypes, s);
 291             Type restype1 = visit(restype, s);
 292             List<Type> thrown1 = visit(thrown, s);
 293             if (argtypes1 == argtypes &&
 294                 restype1 == restype &&
 295                 thrown1 == thrown) return t;
 296             else return new MethodType(argtypes1, restype1, thrown1, t.tsym) {
 297                 @Override
 298                 protected boolean needsStripping() {
 299                     return true;
 300                 }
 301             };
 302         }
 303 
 304         @Override
 305         public Type visitForAll(ForAll t, S s) {
 306             return visit(t.qtype, s);
 307         }
 308     }
 309 
 310     /** map a type function over all immediate descendants of this type
 311      */
 312     public <Z> Type map(TypeMapping<Z> mapping, Z arg) {
 313         return mapping.visit(this, arg);
 314     }
 315 
 316     /** map a type function over all immediate descendants of this type (no arg version)
 317      */
 318     public <Z> Type map(TypeMapping<Z> mapping) {
 319         return mapping.visit(this, null);
 320     }
 321 
 322     /** Define a constant type, of the same kind as this type
 323      *  and with given constant value
 324      */
 325     public Type constType(Object constValue) {
 326         throw new AssertionError();
 327     }
 328 
 329     /**
 330      * If this is a constant type, return its underlying type.
 331      * Otherwise, return the type itself.
 332      */
 333     public Type baseType() {
 334         return this;
 335     }
 336 
 337     /**
 338      * Returns the original version of this type, before metadata were added. This routine is meant
 339      * for internal use only (i.e. {@link Type#equalsIgnoreMetadata(Type)}, {@link Type#stripMetadata});
 340      * it should not be used outside this class.
 341      */
 342     protected Type typeNoMetadata() {
 343         return metadata.isEmpty() ? this : stripMetadata();
 344     }
 345 
 346     /**
 347      * Create a new copy of this type but with the specified TypeMetadata.
 348      * Only to be used internally!
 349      */
 350     protected Type cloneWithMetadata(List<TypeMetadata> metadata) {
 351         throw new AssertionError("Cannot add metadata to this type: " + getTag());
 352     }
 353 
 354     /**
 355      * Get all the type metadata associated with this type.
 356      */
 357     public List<TypeMetadata> getMetadata() {
 358         return metadata;
 359     }
 360 
 361     /**
 362      * Get the type metadata of the given kind associated with this type (if any).
 363      */
 364     public <M extends TypeMetadata> M getMetadata(Class<M> metadataClass) {
 365         return getMetadata(metadataClass, Function.identity(), null);
 366     }
 367 
 368     /**
 369      * Get the type metadata of the given kind associated with this type (if any),
 370      * and apply the provided mapping function.
 371      */
 372     @SuppressWarnings("unchecked")
 373     public <M extends TypeMetadata, Z> Z getMetadata(Class<M> metadataClass, Function<M, Z> metadataFunc, Z defaultValue) {
 374         for (TypeMetadata m : metadata) {
 375             if (m.getClass() == metadataClass) {
 376                 return metadataFunc.apply((M)m);
 377             }
 378         }
 379         return defaultValue;
 380     }
 381 
 382     /**
 383      * Create a new copy of this type but with the specified type metadata.
 384      * If this type is already associated with a type metadata of the same class,
 385      * an exception is thrown.
 386      */
 387     public Type addMetadata(TypeMetadata md) {
 388         Assert.check(getMetadata(md.getClass()) == null);
 389         return cloneWithMetadata(metadata.prepend(md));
 390     }
 391 
 392     /**
 393      * Create a new copy of this type but without the specified type metadata.
 394      */
 395     public Type dropMetadata(Class<? extends TypeMetadata> metadataClass) {
 396         List<TypeMetadata> newMetadata = List.nil();
 397         for (TypeMetadata m : metadata) {
 398             if (m.getClass() != metadataClass) {
 399                 newMetadata = newMetadata.prepend(m);
 400             }
 401         }
 402         return cloneWithMetadata(newMetadata);
 403     }
 404 
 405     /**
 406      * Does this type require annotation stripping for API clients?
 407      */
 408     protected boolean needsStripping() {
 409         return false;
 410     }
 411 
 412     /**
 413      * Strip all metadata associated with this type - this could return a new clone of the type.
 414      * This routine is only used to present the correct annotated types back to the users when types
 415      * are accessed through compiler APIs; it should not be used anywhere in the compiler internals
 416      * as doing so might result in performance penalties.
 417      */
 418     public Type stripMetadataIfNeeded() {
 419         return needsStripping() ?
 420                 accept(stripMetadata, null) :
 421                 this;
 422     }
 423 
 424     public Type stripMetadata() {
 425         return accept(stripMetadata, null);
 426     }
 427     //where
 428         /**
 429          * Note: this visitor only needs to handle cases where
 430          * 'contained' types can be annotated. These cases are
 431          * described in JVMS 4.7.20.2 and are : classes (for type
 432          * parameters and enclosing types), wildcards, and arrays.
 433          */
 434         private static final TypeMapping<Void> stripMetadata = new StructuralTypeMapping<Void>() {
 435             @Override
 436             public Type visitClassType(ClassType t, Void aVoid) {
 437                 return super.visitClassType((ClassType) dropMetadata(t), aVoid);
 438             }
 439 
 440             @Override
 441             public Type visitArrayType(ArrayType t, Void aVoid) {
 442                 return super.visitArrayType((ArrayType) dropMetadata(t), aVoid);
 443             }
 444 
 445             @Override
 446             public Type visitWildcardType(WildcardType wt, Void aVoid) {
 447                 return super.visitWildcardType((WildcardType) dropMetadata(wt), aVoid);
 448             }
 449 
 450             @Override
 451             public Type visitType(Type t, Void aVoid) {
 452                 return dropMetadata(t);
 453             }
 454 
 455             private static Type dropMetadata(Type t) {
 456                 if (t.getMetadata().isEmpty()) {
 457                     return t;
 458                 }
 459                 Type baseType = t.baseType();
 460                 if (baseType.getMetadata().isEmpty()) {
 461                     return baseType;
 462                 }
 463                 return baseType.cloneWithMetadata(List.nil());
 464             }
 465         };
 466 
 467     public Type preannotatedType() {
 468         return addMetadata(new Annotations());
 469     }
 470 
 471     public Type annotatedType(final List<Attribute.TypeCompound> annos) {
 472         return addMetadata(new Annotations(annos));
 473     }
 474 
 475     public boolean isAnnotated() {
 476         return getMetadata(TypeMetadata.Annotations.class) != null;
 477     }
 478 
 479     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 480     public List<Attribute.TypeCompound> getAnnotationMirrors() {
 481         return getMetadata(TypeMetadata.Annotations.class, Annotations::annotations, List.nil());
 482     }
 483 
 484     /** Return the base types of a list of types.
 485      */
 486     public static List<Type> baseTypes(List<Type> ts) {
 487         if (ts.nonEmpty()) {
 488             Type t = ts.head.baseType();
 489             List<Type> baseTypes = baseTypes(ts.tail);
 490             if (t != ts.head || baseTypes != ts.tail)
 491                 return baseTypes.prepend(t);
 492         }
 493         return ts;
 494     }
 495 
 496     protected void appendAnnotationsString(StringBuilder sb,
 497                                          boolean prefix) {
 498         if (isAnnotated()) {
 499             if (prefix) {
 500                 sb.append(" ");
 501             }
 502             sb.append(getAnnotationMirrors().toString(" "));
 503             sb.append(" ");
 504         }
 505     }
 506 
 507     protected void appendAnnotationsString(StringBuilder sb) {
 508         appendAnnotationsString(sb, false);
 509     }
 510 
 511     /** The Java source which this type represents.
 512      */
 513     @DefinedBy(Api.LANGUAGE_MODEL)
 514     public String toString() {
 515         StringBuilder sb = new StringBuilder();
 516         appendAnnotationsString(sb);
 517         if (tsym == null || tsym.name == null) {
 518             sb.append("<none>");
 519         } else {
 520             sb.append(tsym.name.toString());
 521         }
 522         if (moreInfo && hasTag(TYPEVAR)) {
 523             sb.append(hashCode());
 524         }
 525         return sb.toString();
 526     }
 527 
 528     /**
 529      * The Java source which this type list represents.  A List is
 530      * represented as a comma-separated listing of the elements in
 531      * that list.
 532      */
 533     public static String toString(List<Type> ts) {
 534         if (ts.isEmpty()) {
 535             return "";
 536         } else {
 537             StringBuilder buf = new StringBuilder();
 538             buf.append(ts.head.toString());
 539             for (List<Type> l = ts.tail; l.nonEmpty(); l = l.tail)
 540                 buf.append(",").append(l.head.toString());
 541             return buf.toString();
 542         }
 543     }
 544 
 545     /**
 546      * The constant value of this type, converted to String
 547      */
 548     public String stringValue() {
 549         Object cv = Assert.checkNonNull(constValue());
 550         return cv.toString();
 551     }
 552 
 553     /**
 554      * Override this method with care. For most Type instances this should behave as ==.
 555      */
 556     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 557     public boolean equals(Object t) {
 558         return this == t;
 559     }
 560 
 561     public boolean equalsIgnoreMetadata(Type t) {
 562         return typeNoMetadata().equals(t.typeNoMetadata());
 563     }
 564 
 565     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 566     public int hashCode() {
 567         return super.hashCode();
 568     }
 569 
 570     public String argtypes(boolean varargs) {
 571         List<Type> args = getParameterTypes();
 572         if (!varargs) return args.toString();
 573         StringBuilder buf = new StringBuilder();
 574         while (args.tail.nonEmpty()) {
 575             buf.append(args.head);
 576             args = args.tail;
 577             buf.append(',');
 578         }
 579         if (args.head.hasTag(ARRAY)) {
 580             buf.append(((ArrayType)args.head).elemtype);
 581             if (args.head.getAnnotationMirrors().nonEmpty()) {
 582                 buf.append(args.head.getAnnotationMirrors());
 583             }
 584             buf.append("...");
 585         } else {
 586             buf.append(args.head);
 587         }
 588         return buf.toString();
 589     }
 590 
 591     /** Access methods.
 592      */
 593     public List<Type>        getTypeArguments()  { return List.nil(); }
 594     public Type              getEnclosingType()  { return null; }
 595     public List<Type>        getParameterTypes() { return List.nil(); }
 596     public Type              getReturnType()     { return null; }
 597     public Type              getReceiverType()   { return null; }
 598     public List<Type>        getThrownTypes()    { return List.nil(); }
 599     public Type              getUpperBound()     { return null; }
 600     public Type              getLowerBound()     { return null; }
 601 
 602     /* Navigation methods, these will work for classes, type variables,
 603      *  foralls, but will return null for arrays and methods.
 604      */
 605 
 606    /** Return all parameters of this type and all its outer types in order
 607     *  outer (first) to inner (last).
 608     */
 609     public List<Type> allparams() { return List.nil(); }
 610 
 611     /** Does this type contain "error" elements?
 612      */
 613     public boolean isErroneous() {
 614         return false;
 615     }
 616 
 617     public static boolean isErroneous(List<Type> ts) {
 618         for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
 619             if (l.head.isErroneous()) return true;
 620         return false;
 621     }
 622 
 623     /** Is this type parameterized?
 624      *  A class type is parameterized if it has some parameters.
 625      *  An array type is parameterized if its element type is parameterized.
 626      *  All other types are not parameterized.
 627      */
 628     public boolean isParameterized() {
 629         return false;
 630     }
 631 
 632     /** Is this type a raw type?
 633      *  A class type is a raw type if it misses some of its parameters.
 634      *  An array type is a raw type if its element type is raw.
 635      *  All other types are not raw.
 636      *  Type validation will ensure that the only raw types
 637      *  in a program are types that miss all their type variables.
 638      */
 639     public boolean isRaw() {
 640         return false;
 641     }
 642 
 643     /**
 644      * A compound type is a special class type whose supertypes are used to store a list
 645      * of component types. There are two kinds of compound types: (i) intersection types
 646      * {@link IntersectionClassType} and (ii) union types {@link UnionClassType}.
 647      */
 648     public boolean isCompound() {
 649         return false;
 650     }
 651 
 652     public boolean isIntersection() {
 653         return false;
 654     }
 655 
 656     public boolean isUnion() {
 657         return false;
 658     }
 659 
 660     public boolean isInterface() {
 661         return (tsym.flags() & INTERFACE) != 0;
 662     }
 663 
 664     public boolean isFinal() {
 665         return (tsym.flags() & FINAL) != 0;
 666     }
 667 
 668     public boolean isValueBased() {
 669         return tsym != null && (tsym.flags_field & VALUE_BASED) != 0;
 670     }
 671 
 672     /**
 673      * Does this type contain occurrences of type t?
 674      */
 675     public boolean contains(Type t) {
 676         return t.equalsIgnoreMetadata(this);
 677     }
 678 
 679     public static boolean contains(List<Type> ts, Type t) {
 680         for (List<Type> l = ts;
 681              l.tail != null /*inlined: l.nonEmpty()*/;
 682              l = l.tail)
 683             if (l.head.contains(t)) return true;
 684         return false;
 685     }
 686 
 687     /** Does this type contain an occurrence of some type in 'ts'?
 688      */
 689     public boolean containsAny(List<Type> ts) {
 690         for (Type t : ts)
 691             if (this.contains(t)) return true;
 692         return false;
 693     }
 694 
 695     public static boolean containsAny(List<Type> ts1, List<Type> ts2) {
 696         for (Type t : ts1)
 697             if (t.containsAny(ts2)) return true;
 698         return false;
 699     }
 700 
 701     public static List<Type> filter(List<Type> ts, Predicate<Type> tf) {
 702         ListBuffer<Type> buf = new ListBuffer<>();
 703         for (Type t : ts) {
 704             if (tf.test(t)) {
 705                 buf.append(t);
 706             }
 707         }
 708         return buf.toList();
 709     }
 710 
 711     public boolean isSuperBound() { return false; }
 712     public boolean isExtendsBound() { return false; }
 713     public boolean isUnbound() { return false; }
 714     public Type withTypeVar(Type t) { return this; }
 715 
 716     /** The underlying method type of this type.
 717      */
 718     public MethodType asMethodType() { throw new AssertionError(); }
 719 
 720     /** Complete loading all classes in this type.
 721      */
 722     public void complete() {}
 723 
 724     public TypeSymbol asElement() {
 725         return tsym;
 726     }
 727 
 728     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 729     public TypeKind getKind() {
 730         return TypeKind.OTHER;
 731     }
 732 
 733     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 734     public <R, P> R accept(TypeVisitor<R, P> v, P p) {
 735         throw new AssertionError();
 736     }
 737 
 738     public static class JCPrimitiveType extends Type
 739             implements javax.lang.model.type.PrimitiveType {
 740 
 741         TypeTag tag;
 742 
 743         public JCPrimitiveType(TypeTag tag, TypeSymbol tsym) {
 744             this(tag, tsym, List.nil());
 745         }
 746 
 747         private JCPrimitiveType(TypeTag tag, TypeSymbol tsym, List<TypeMetadata> metadata) {
 748             super(tsym, metadata);
 749             this.tag = tag;
 750             Assert.check(tag.isPrimitive);
 751         }
 752 
 753         @Override
 754         protected JCPrimitiveType cloneWithMetadata(List<TypeMetadata> md) {
 755             return new JCPrimitiveType(tag, tsym, md) {
 756                 @Override
 757                 public Type baseType() { return JCPrimitiveType.this.baseType(); }
 758             };
 759         }
 760 
 761         @Override
 762         public boolean isNumeric() {
 763             return tag != BOOLEAN;
 764         }
 765 
 766         @Override
 767         public boolean isIntegral() {
 768             switch (tag) {
 769                 case CHAR:
 770                 case BYTE:
 771                 case SHORT:
 772                 case INT:
 773                 case LONG:
 774                     return true;
 775                 default:
 776                     return false;
 777             }
 778         }
 779 
 780         @Override
 781         public boolean isPrimitive() {
 782             return true;
 783         }
 784 
 785         @Override
 786         public TypeTag getTag() {
 787             return tag;
 788         }
 789 
 790         @Override
 791         public boolean isPrimitiveOrVoid() {
 792             return true;
 793         }
 794 
 795         /** Define a constant type, of the same kind as this type
 796          *  and with given constant value
 797          */
 798         @Override
 799         public Type constType(Object constValue) {
 800             return addMetadata(new ConstantValue(constValue));
 801         }
 802 
 803         /**
 804          * The constant value of this type, converted to String
 805          */
 806         @Override
 807         public String stringValue() {
 808             Object cv = Assert.checkNonNull(constValue());
 809             if (tag == BOOLEAN) {
 810                 return ((Integer) cv).intValue() == 0 ? "false" : "true";
 811             }
 812             else if (tag == CHAR) {
 813                 return String.valueOf((char) ((Integer) cv).intValue());
 814             }
 815             else {
 816                 return cv.toString();
 817             }
 818         }
 819 
 820         /** Is this a constant type whose value is false?
 821          */
 822         @Override
 823         public boolean isFalse() {
 824             return
 825                 tag == BOOLEAN &&
 826                 constValue() != null &&
 827                 ((Integer)constValue()).intValue() == 0;
 828         }
 829 
 830         /** Is this a constant type whose value is true?
 831          */
 832         @Override
 833         public boolean isTrue() {
 834             return
 835                 tag == BOOLEAN &&
 836                 constValue() != null &&
 837                 ((Integer)constValue()).intValue() != 0;
 838         }
 839 
 840         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 841         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
 842             return v.visitPrimitive(this, p);
 843         }
 844 
 845         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 846         public TypeKind getKind() {
 847             switch (tag) {
 848                 case BYTE:      return TypeKind.BYTE;
 849                 case CHAR:      return TypeKind.CHAR;
 850                 case SHORT:     return TypeKind.SHORT;
 851                 case INT:       return TypeKind.INT;
 852                 case LONG:      return TypeKind.LONG;
 853                 case FLOAT:     return TypeKind.FLOAT;
 854                 case DOUBLE:    return TypeKind.DOUBLE;
 855                 case BOOLEAN:   return TypeKind.BOOLEAN;
 856             }
 857             throw new AssertionError();
 858         }
 859 
 860     }
 861 
 862     public static class WildcardType extends Type
 863             implements javax.lang.model.type.WildcardType {
 864 
 865         public Type type;
 866         public BoundKind kind;
 867         public TypeVar bound;
 868 
 869         @Override
 870         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
 871             return v.visitWildcardType(this, s);
 872         }
 873 
 874         public WildcardType(Type type, BoundKind kind, TypeSymbol tsym) {
 875             this(type, kind, tsym, null, List.nil());
 876         }
 877 
 878         public WildcardType(Type type, BoundKind kind, TypeSymbol tsym,
 879                             List<TypeMetadata> metadata) {
 880             this(type, kind, tsym, null, metadata);
 881         }
 882 
 883         public WildcardType(Type type, BoundKind kind, TypeSymbol tsym,
 884                             TypeVar bound) {
 885             this(type, kind, tsym, bound, List.nil());
 886         }
 887 
 888         public WildcardType(Type type, BoundKind kind, TypeSymbol tsym,
 889                             TypeVar bound, List<TypeMetadata> metadata) {
 890             super(tsym, metadata);
 891             this.type = Assert.checkNonNull(type);
 892             this.kind = kind;
 893             this.bound = bound;
 894         }
 895 
 896         @Override
 897         protected WildcardType cloneWithMetadata(List<TypeMetadata> md) {
 898             return new WildcardType(type, kind, tsym, bound, md) {
 899                 @Override
 900                 public Type baseType() { return WildcardType.this.baseType(); }
 901             };
 902         }
 903 
 904         @Override
 905         public TypeTag getTag() {
 906             return WILDCARD;
 907         }
 908 
 909         @Override
 910         public boolean contains(Type t) {
 911             return kind != UNBOUND && type.contains(t);
 912         }
 913 
 914         public boolean isSuperBound() {
 915             return kind == SUPER ||
 916                 kind == UNBOUND;
 917         }
 918         public boolean isExtendsBound() {
 919             return kind == EXTENDS ||
 920                 kind == UNBOUND;
 921         }
 922         public boolean isUnbound() {
 923             // is it `?` or `? extends Object`?
 924             return kind == UNBOUND ||
 925                     (kind == EXTENDS && type.tsym.flatName() == type.tsym.name.table.names.java_lang_Object);
 926         }
 927 
 928         @Override
 929         public boolean isReference() {
 930             return true;
 931         }
 932 
 933         @Override
 934         public boolean isNullOrReference() {
 935             return true;
 936         }
 937 
 938         @Override
 939         public Type withTypeVar(Type t) {
 940             //-System.err.println(this+".withTypeVar("+t+");");//DEBUG
 941             if (bound == t)
 942                 return this;
 943             bound = (TypeVar)t;
 944             return this;
 945         }
 946 
 947         boolean isPrintingBound = false;
 948         @DefinedBy(Api.LANGUAGE_MODEL)
 949         public String toString() {
 950             StringBuilder s = new StringBuilder();
 951             appendAnnotationsString(s);
 952             s.append(kind.toString());
 953             if (kind != UNBOUND)
 954                 s.append(type);
 955             if (moreInfo && bound != null && !isPrintingBound)
 956                 try {
 957                     isPrintingBound = true;
 958                     s.append("{:").append(bound.getUpperBound()).append(":}");
 959                 } finally {
 960                     isPrintingBound = false;
 961                 }
 962             return s.toString();
 963         }
 964 
 965         @DefinedBy(Api.LANGUAGE_MODEL)
 966         public Type getExtendsBound() {
 967             if (kind == EXTENDS)
 968                 return type;
 969             else
 970                 return null;
 971         }
 972 
 973         @DefinedBy(Api.LANGUAGE_MODEL)
 974         public Type getSuperBound() {
 975             if (kind == SUPER)
 976                 return type;
 977             else
 978                 return null;
 979         }
 980 
 981         @DefinedBy(Api.LANGUAGE_MODEL)
 982         public TypeKind getKind() {
 983             return TypeKind.WILDCARD;
 984         }
 985 
 986         @DefinedBy(Api.LANGUAGE_MODEL)
 987         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
 988             return v.visitWildcard(this, p);
 989         }
 990     }
 991 
 992     public static class ClassType extends Type implements DeclaredType, LoadableConstant,
 993                                                           javax.lang.model.type.ErrorType {
 994 
 995         /** The enclosing type of this type. If this is the type of an inner
 996          *  class, outer_field refers to the type of its enclosing
 997          *  instance class, in all other cases it refers to noType.
 998          */
 999         private Type outer_field;
1000 
1001         /** The type parameters of this type (to be set once class is loaded).
1002          */
1003         public List<Type> typarams_field;
1004 
1005         /** A cache variable for the type parameters of this type,
1006          *  appended to all parameters of its enclosing class.
1007          *  @see #allparams
1008          */
1009         public List<Type> allparams_field;
1010 
1011         /** The supertype of this class (to be set once class is loaded).
1012          */
1013         public Type supertype_field;
1014 
1015         /** The interfaces of this class (to be set once class is loaded).
1016          */
1017         public List<Type> interfaces_field;
1018 
1019         /** All the interfaces of this class, including missing ones.
1020          */
1021         public List<Type> all_interfaces_field;
1022 
1023         public ClassType(Type outer, List<Type> typarams, TypeSymbol tsym) {
1024             this(outer, typarams, tsym, List.nil());
1025         }
1026 
1027         public ClassType(Type outer, List<Type> typarams, TypeSymbol tsym,
1028                          List<TypeMetadata> metadata) {
1029             super(tsym, metadata);
1030             this.outer_field = outer;
1031             this.typarams_field = typarams;
1032             this.allparams_field = null;
1033             this.supertype_field = null;
1034             this.interfaces_field = null;
1035         }
1036 
1037         public int poolTag() {
1038             return ClassFile.CONSTANT_Class;
1039         }
1040 
1041         @Override
1042         protected ClassType cloneWithMetadata(List<TypeMetadata> md) {
1043             return new ClassType(outer_field, typarams_field, tsym, md) {
1044                 @Override
1045                 public Type baseType() { return ClassType.this.baseType(); }
1046             };
1047         }
1048 
1049         @Override
1050         public TypeTag getTag() {
1051             return CLASS;
1052         }
1053 
1054         @Override
1055         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1056             return v.visitClassType(this, s);
1057         }
1058 
1059         public Type constType(Object constValue) {
1060             return addMetadata(new ConstantValue(constValue));
1061         }
1062 
1063         /** The Java source which this type represents.
1064          */
1065         @DefinedBy(Api.LANGUAGE_MODEL)
1066         public String toString() {
1067             StringBuilder buf = new StringBuilder();
1068             if (getEnclosingType().hasTag(CLASS) && tsym.owner.kind == TYP) {
1069                 buf.append(getEnclosingType().toString());
1070                 buf.append(".");
1071                 appendAnnotationsString(buf);
1072                 buf.append(className(tsym, false));
1073             } else {
1074                 if (isAnnotated()) {
1075                     if (!tsym.packge().isUnnamed()) {
1076                         buf.append(tsym.packge());
1077                         buf.append(".");
1078                     }
1079                     ListBuffer<Name> names = new ListBuffer<>();
1080                     for (Symbol sym = tsym.owner; sym != null && sym.kind == TYP; sym = sym.owner) {
1081                         names.prepend(sym.name);
1082                     }
1083                     for (Name name : names) {
1084                         buf.append(name);
1085                         buf.append(".");
1086                     }
1087                     appendAnnotationsString(buf);
1088                     buf.append(tsym.name);
1089                 } else {
1090                     buf.append(className(tsym, true));
1091                 }
1092             }
1093 
1094             if (getTypeArguments().nonEmpty()) {
1095                 buf.append('<');
1096                 buf.append(getTypeArguments().toString());
1097                 buf.append(">");
1098             }
1099             return buf.toString();
1100         }
1101 //where
1102             private String className(Symbol sym, boolean longform) {
1103                 if (sym.name.isEmpty() && (sym.flags() & COMPOUND) != 0) {
1104                     StringBuilder s = new StringBuilder(supertype_field.toString());
1105                     for (List<Type> is=interfaces_field; is.nonEmpty(); is = is.tail) {
1106                         s.append("&");
1107                         s.append(is.head.toString());
1108                     }
1109                     return s.toString();
1110                 } else if (sym.name.isEmpty()) {
1111                     String s;
1112                     ClassType norm = (ClassType) tsym.type;
1113                     if (norm == null) {
1114                         s = Log.getLocalizedString("anonymous.class", (Object)null);
1115                     } else if (norm.interfaces_field != null && norm.interfaces_field.nonEmpty()) {
1116                         s = Log.getLocalizedString("anonymous.class",
1117                                                    norm.interfaces_field.head);
1118                     } else {
1119                         s = Log.getLocalizedString("anonymous.class",
1120                                                    norm.supertype_field);
1121                     }
1122                     if (moreInfo)
1123                         s += String.valueOf(sym.hashCode());
1124                     return s;
1125                 } else if (longform) {
1126                     sym.apiComplete();
1127                     return sym.getQualifiedName().toString();
1128                 } else {
1129                     return sym.name.toString();
1130                 }
1131             }
1132 
1133         @DefinedBy(Api.LANGUAGE_MODEL)
1134         public List<Type> getTypeArguments() {
1135             if (typarams_field == null) {
1136                 complete();
1137                 if (typarams_field == null)
1138                     typarams_field = List.nil();
1139             }
1140             return typarams_field;
1141         }
1142 
1143         public boolean hasErasedSupertypes() {
1144             return isRaw();
1145         }
1146 
1147         @DefinedBy(Api.LANGUAGE_MODEL)
1148         public Type getEnclosingType() {
1149             return outer_field;
1150         }
1151 
1152         public void setEnclosingType(Type outer) {
1153             outer_field = outer;
1154         }
1155 
1156         public List<Type> allparams() {
1157             if (allparams_field == null) {
1158                 allparams_field = getTypeArguments().prependList(getEnclosingType().allparams());
1159             }
1160             return allparams_field;
1161         }
1162 
1163         public boolean isErroneous() {
1164             return
1165                 getEnclosingType().isErroneous() ||
1166                 isErroneous(getTypeArguments()) ||
1167                 this != tsym.type && tsym.type.isErroneous();
1168         }
1169 
1170         public boolean isParameterized() {
1171             return allparams().tail != null;
1172             // optimization, was: allparams().nonEmpty();
1173         }
1174 
1175         @Override
1176         public boolean isReference() {
1177             return true;
1178         }
1179 
1180         @Override
1181         public boolean isNullOrReference() {
1182             return true;
1183         }
1184 
1185         /** A cache for the rank. */
1186         int rank_field = -1;
1187 
1188         /** A class type is raw if it misses some
1189          *  of its type parameter sections.
1190          *  After validation, this is equivalent to:
1191          *  {@code allparams.isEmpty() && tsym.type.allparams.nonEmpty(); }
1192          */
1193         public boolean isRaw() {
1194             return
1195                 this != tsym.type && // necessary, but not sufficient condition
1196                 tsym.type.allparams().nonEmpty() &&
1197                 allparams().isEmpty();
1198         }
1199 
1200         public boolean contains(Type elem) {
1201             return
1202                 elem.equalsIgnoreMetadata(this)
1203                 || (isParameterized()
1204                     && (getEnclosingType().contains(elem) || contains(getTypeArguments(), elem)))
1205                 || (isCompound()
1206                     && (supertype_field.contains(elem) || contains(interfaces_field, elem)));
1207         }
1208 
1209         public void complete() {
1210             tsym.complete();
1211         }
1212 
1213         @DefinedBy(Api.LANGUAGE_MODEL)
1214         public TypeKind getKind() {
1215             tsym.apiComplete();
1216             return tsym.kind == TYP ? TypeKind.DECLARED : TypeKind.ERROR;
1217         }
1218 
1219         @DefinedBy(Api.LANGUAGE_MODEL)
1220         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1221             return v.visitDeclared(this, p);
1222         }
1223     }
1224 
1225     public static class ErasedClassType extends ClassType {
1226         public ErasedClassType(Type outer, TypeSymbol tsym,
1227                                List<TypeMetadata> metadata) {
1228             super(outer, List.nil(), tsym, metadata);
1229         }
1230 
1231         @Override
1232         public boolean hasErasedSupertypes() {
1233             return true;
1234         }
1235     }
1236 
1237     // a clone of a ClassType that knows about the alternatives of a union type.
1238     public static class UnionClassType extends ClassType implements UnionType {
1239         final List<? extends Type> alternatives_field;
1240 
1241         public UnionClassType(ClassType ct, List<? extends Type> alternatives) {
1242             // Presently no way to refer to this type directly, so we
1243             // cannot put annotations directly on it.
1244             super(ct.outer_field, ct.typarams_field, ct.tsym);
1245             allparams_field = ct.allparams_field;
1246             supertype_field = ct.supertype_field;
1247             interfaces_field = ct.interfaces_field;
1248             all_interfaces_field = ct.interfaces_field;
1249             alternatives_field = alternatives;
1250         }
1251 
1252         public Type getLub() {
1253             return tsym.type;
1254         }
1255 
1256         @DefinedBy(Api.LANGUAGE_MODEL)
1257         public java.util.List<? extends TypeMirror> getAlternatives() {
1258             return Collections.unmodifiableList(alternatives_field);
1259         }
1260 
1261         @Override
1262         public boolean isUnion() {
1263             return true;
1264         }
1265 
1266         @Override
1267         public boolean isCompound() {
1268             return getLub().isCompound();
1269         }
1270 
1271         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1272         public TypeKind getKind() {
1273             return TypeKind.UNION;
1274         }
1275 
1276         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1277         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1278             return v.visitUnion(this, p);
1279         }
1280 
1281         public Iterable<? extends Type> getAlternativeTypes() {
1282             return alternatives_field;
1283         }
1284     }
1285 
1286     // a clone of a ClassType that knows about the bounds of an intersection type.
1287     public static class IntersectionClassType extends ClassType implements IntersectionType {
1288 
1289         public boolean allInterfaces;
1290 
1291         public IntersectionClassType(List<Type> bounds, ClassSymbol csym, boolean allInterfaces) {
1292             // Presently no way to refer to this type directly, so we
1293             // cannot put annotations directly on it.
1294             super(Type.noType, List.nil(), csym);
1295             this.allInterfaces = allInterfaces;
1296             Assert.check((csym.flags() & COMPOUND) != 0);
1297             supertype_field = bounds.head;
1298             interfaces_field = bounds.tail;
1299             Assert.check(!supertype_field.tsym.isCompleted() ||
1300                     !supertype_field.isInterface(), supertype_field);
1301         }
1302 
1303         @DefinedBy(Api.LANGUAGE_MODEL)
1304         public java.util.List<? extends TypeMirror> getBounds() {
1305             return Collections.unmodifiableList(getExplicitComponents());
1306         }
1307 
1308         @Override
1309         public boolean isCompound() {
1310             return true;
1311         }
1312 
1313         public List<Type> getComponents() {
1314             return interfaces_field.prepend(supertype_field);
1315         }
1316 
1317         @Override
1318         public boolean isIntersection() {
1319             return true;
1320         }
1321 
1322         public List<Type> getExplicitComponents() {
1323             return allInterfaces ?
1324                     interfaces_field :
1325                     getComponents();
1326         }
1327 
1328         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1329         public TypeKind getKind() {
1330             return TypeKind.INTERSECTION;
1331         }
1332 
1333         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1334         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1335             return v.visitIntersection(this, p);
1336         }
1337     }
1338 
1339     public static class ArrayType extends Type
1340             implements LoadableConstant, javax.lang.model.type.ArrayType {
1341 
1342         public Type elemtype;
1343 
1344         public ArrayType(Type elemtype, TypeSymbol arrayClass) {
1345             this(elemtype, arrayClass, List.nil());
1346         }
1347 
1348         public ArrayType(Type elemtype, TypeSymbol arrayClass,
1349                          List<TypeMetadata> metadata) {
1350             super(arrayClass, metadata);
1351             this.elemtype = elemtype;
1352         }
1353 
1354         public ArrayType(ArrayType that) {
1355             //note: type metadata is deliberately shared here, as we want side-effects from annotation
1356             //processing to flow from original array to the cloned array.
1357             this(that.elemtype, that.tsym, that.getMetadata());
1358         }
1359 
1360         public int poolTag() {
1361             return ClassFile.CONSTANT_Class;
1362         }
1363 
1364         @Override
1365         protected ArrayType cloneWithMetadata(List<TypeMetadata> md) {
1366             return new ArrayType(elemtype, tsym, md) {
1367                 @Override
1368                 public Type baseType() { return ArrayType.this.baseType(); }
1369             };
1370         }
1371 
1372         @Override
1373         public TypeTag getTag() {
1374             return ARRAY;
1375         }
1376 
1377         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1378             return v.visitArrayType(this, s);
1379         }
1380 
1381         @DefinedBy(Api.LANGUAGE_MODEL)
1382         public String toString() {
1383             StringBuilder sb = new StringBuilder();
1384 
1385             // First append root component type
1386             Type t = elemtype;
1387             while (t.getKind() == TypeKind.ARRAY)
1388                 t = ((ArrayType) t).getComponentType();
1389             sb.append(t);
1390 
1391             // then append @Anno[] @Anno[] ... @Anno[]
1392             t = this;
1393             do {
1394                 t.appendAnnotationsString(sb, true);
1395                 sb.append("[]");
1396                 t = ((ArrayType) t).getComponentType();
1397             } while (t.getKind() == TypeKind.ARRAY);
1398 
1399             return sb.toString();
1400         }
1401 
1402         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1403         public boolean equals(Object obj) {
1404             return (obj instanceof ArrayType arrayType)
1405                     && (this == arrayType || elemtype.equals(arrayType.elemtype));
1406         }
1407 
1408         @DefinedBy(Api.LANGUAGE_MODEL)
1409         public int hashCode() {
1410             return (ARRAY.ordinal() << 5) + elemtype.hashCode();
1411         }
1412 
1413         public boolean isVarargs() {
1414             return false;
1415         }
1416 
1417         public List<Type> allparams() { return elemtype.allparams(); }
1418 
1419         public boolean isErroneous() {
1420             return elemtype.isErroneous();
1421         }
1422 
1423         public boolean isParameterized() {
1424             return elemtype.isParameterized();
1425         }
1426 
1427         @Override
1428         public boolean isReference() {
1429             return true;
1430         }
1431 
1432         @Override
1433         public boolean isNullOrReference() {
1434             return true;
1435         }
1436 
1437         public boolean isRaw() {
1438             return elemtype.isRaw();
1439         }
1440 
1441         public ArrayType makeVarargs() {
1442             return new ArrayType(elemtype, tsym, metadata) {
1443                 @Override
1444                 public boolean isVarargs() {
1445                     return true;
1446                 }
1447             };
1448         }
1449 
1450         public boolean contains(Type elem) {
1451             return elem.equalsIgnoreMetadata(this) || elemtype.contains(elem);
1452         }
1453 
1454         public void complete() {
1455             elemtype.complete();
1456         }
1457 
1458         @DefinedBy(Api.LANGUAGE_MODEL)
1459         public Type getComponentType() {
1460             return elemtype;
1461         }
1462 
1463         @DefinedBy(Api.LANGUAGE_MODEL)
1464         public TypeKind getKind() {
1465             return TypeKind.ARRAY;
1466         }
1467 
1468         @DefinedBy(Api.LANGUAGE_MODEL)
1469         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1470             return v.visitArray(this, p);
1471         }
1472     }
1473 
1474     public static class MethodType extends Type implements ExecutableType, LoadableConstant {
1475 
1476         public List<Type> argtypes;
1477         public Type restype;
1478         public List<Type> thrown;
1479 
1480         /** The type annotations on the method receiver.
1481          */
1482         public Type recvtype;
1483 
1484         public MethodType(List<Type> argtypes,
1485                           Type restype,
1486                           List<Type> thrown,
1487                           TypeSymbol methodClass) {
1488             // Presently no way to refer to a method type directly, so
1489             // we cannot put type annotations on it.
1490             super(methodClass, List.nil());
1491             this.argtypes = argtypes;
1492             this.restype = restype;
1493             this.thrown = thrown;
1494         }
1495 
1496         @Override
1497         public TypeTag getTag() {
1498             return METHOD;
1499         }
1500 
1501         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1502             return v.visitMethodType(this, s);
1503         }
1504 
1505         /** The Java source which this type represents.
1506          *
1507          *  XXX 06/09/99 iris This isn't correct Java syntax, but it probably
1508          *  should be.
1509          */
1510         @DefinedBy(Api.LANGUAGE_MODEL)
1511         public String toString() {
1512             StringBuilder sb = new StringBuilder();
1513             appendAnnotationsString(sb);
1514             sb.append('(');
1515             sb.append(argtypes);
1516             sb.append(')');
1517             sb.append(restype);
1518             return sb.toString();
1519         }
1520 
1521         @DefinedBy(Api.LANGUAGE_MODEL)
1522         public List<Type>        getParameterTypes() { return argtypes; }
1523         @DefinedBy(Api.LANGUAGE_MODEL)
1524         public Type              getReturnType()     { return restype; }
1525         @DefinedBy(Api.LANGUAGE_MODEL)
1526         public Type              getReceiverType()   {
1527             return (recvtype == null) ? Type.noType : recvtype;
1528         }
1529         @DefinedBy(Api.LANGUAGE_MODEL)
1530         public List<Type>        getThrownTypes()    { return thrown; }
1531 
1532         public boolean isErroneous() {
1533             return
1534                 isErroneous(argtypes) ||
1535                 restype != null && restype.isErroneous();
1536         }
1537 
1538         @Override
1539         public int poolTag() {
1540             return ClassFile.CONSTANT_MethodType;
1541         }
1542 
1543         public boolean contains(Type elem) {
1544             return elem.equalsIgnoreMetadata(this) || contains(argtypes, elem) || restype.contains(elem) || contains(thrown, elem);
1545         }
1546 
1547         public MethodType asMethodType() { return this; }
1548 
1549         public void complete() {
1550             for (List<Type> l = argtypes; l.nonEmpty(); l = l.tail)
1551                 l.head.complete();
1552             restype.complete();
1553             recvtype.complete();
1554             for (List<Type> l = thrown; l.nonEmpty(); l = l.tail)
1555                 l.head.complete();
1556         }
1557 
1558         @DefinedBy(Api.LANGUAGE_MODEL)
1559         public List<TypeVar> getTypeVariables() {
1560             return List.nil();
1561         }
1562 
1563         public TypeSymbol asElement() {
1564             return null;
1565         }
1566 
1567         @DefinedBy(Api.LANGUAGE_MODEL)
1568         public TypeKind getKind() {
1569             return TypeKind.EXECUTABLE;
1570         }
1571 
1572         @DefinedBy(Api.LANGUAGE_MODEL)
1573         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1574             return v.visitExecutable(this, p);
1575         }
1576     }
1577 
1578     public static class PackageType extends Type implements NoType {
1579 
1580         PackageType(PackageSymbol tsym) {
1581             // Package types cannot be annotated
1582             super(tsym, List.nil());
1583         }
1584 
1585         @Override
1586         public TypeTag getTag() {
1587             return PACKAGE;
1588         }
1589 
1590         @Override
1591         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1592             return v.visitPackageType(this, s);
1593         }
1594 
1595         @DefinedBy(Api.LANGUAGE_MODEL)
1596         public String toString() {
1597             return tsym.getQualifiedName().toString();
1598         }
1599 
1600         @DefinedBy(Api.LANGUAGE_MODEL)
1601         public TypeKind getKind() {
1602             return TypeKind.PACKAGE;
1603         }
1604 
1605         @DefinedBy(Api.LANGUAGE_MODEL)
1606         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1607             return v.visitNoType(this, p);
1608         }
1609     }
1610 
1611     public static class ModuleType extends Type implements NoType {
1612 
1613         ModuleType(ModuleSymbol tsym) {
1614             // Module types cannot be annotated
1615             super(tsym, List.nil());
1616         }
1617 
1618         @Override
1619         public ModuleType annotatedType(List<Attribute.TypeCompound> annos) {
1620             throw new AssertionError("Cannot annotate a module type");
1621         }
1622 
1623         @Override
1624         public TypeTag getTag() {
1625             return TypeTag.MODULE;
1626         }
1627 
1628         @Override
1629         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1630             return v.visitModuleType(this, s);
1631         }
1632 
1633         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1634         public String toString() {
1635             return tsym.getQualifiedName().toString();
1636         }
1637 
1638         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1639         public TypeKind getKind() {
1640             return TypeKind.MODULE;
1641         }
1642 
1643         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1644         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1645             return v.visitNoType(this, p);
1646         }
1647     }
1648 
1649     public static class TypeVar extends Type implements TypeVariable {
1650 
1651         /** The upper bound of this type variable; set from outside.
1652          *  Must be nonempty once it is set.
1653          *  For a bound, `bound' is the bound type itself.
1654          *  Multiple bounds are expressed as a single class type which has the
1655          *  individual bounds as superclass, respectively interfaces.
1656          *  The class type then has as `tsym' a compiler generated class `c',
1657          *  which has a flag COMPOUND and whose owner is the type variable
1658          *  itself. Furthermore, the erasure_field of the class
1659          *  points to the first class or interface bound.
1660          */
1661         private Type _bound = null;
1662 
1663         /** The lower bound of this type variable.
1664          *  TypeVars don't normally have a lower bound, so it is normally set
1665          *  to syms.botType.
1666          *  Subtypes, such as CapturedType, may provide a different value.
1667          */
1668         public Type lower;
1669 
1670         @SuppressWarnings("this-escape")
1671         public TypeVar(Name name, Symbol owner, Type lower) {
1672             super(null, List.nil());
1673             Assert.checkNonNull(lower);
1674             tsym = new TypeVariableSymbol(0, name, this, owner);
1675             this.setUpperBound(null);
1676             this.lower = lower;
1677         }
1678 
1679         public TypeVar(TypeSymbol tsym, Type bound, Type lower) {
1680             this(tsym, bound, lower, List.nil());
1681         }
1682 
1683         @SuppressWarnings("this-escape")
1684         public TypeVar(TypeSymbol tsym, Type bound, Type lower,
1685                        List<TypeMetadata> metadata) {
1686             super(tsym, metadata);
1687             Assert.checkNonNull(lower);
1688             this.setUpperBound(bound);
1689             this.lower = lower;
1690         }
1691 
1692         @Override
1693         protected TypeVar cloneWithMetadata(List<TypeMetadata> md) {
1694             return new TypeVar(tsym, getUpperBound(), lower, md) {
1695                 @Override
1696                 public Type baseType() { return TypeVar.this.baseType(); }
1697 
1698                 @Override @DefinedBy(Api.LANGUAGE_MODEL)
1699                 public Type getUpperBound() { return TypeVar.this.getUpperBound(); }
1700 
1701                 public void setUpperBound(Type bound) { TypeVar.this.setUpperBound(bound); }
1702             };
1703         }
1704 
1705         @Override
1706         public TypeTag getTag() {
1707             return TYPEVAR;
1708         }
1709 
1710         @Override
1711         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1712             return v.visitTypeVar(this, s);
1713         }
1714 
1715         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1716         public Type getUpperBound() { return _bound; }
1717 
1718         public void setUpperBound(Type bound) { this._bound = bound; }
1719 
1720         int rank_field = -1;
1721 
1722         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1723         public Type getLowerBound() {
1724             return lower;
1725         }
1726 
1727         @DefinedBy(Api.LANGUAGE_MODEL)
1728         public TypeKind getKind() {
1729             return TypeKind.TYPEVAR;
1730         }
1731 
1732         public boolean isCaptured() {
1733             return false;
1734         }
1735 
1736         @Override
1737         public boolean isReference() {
1738             return true;
1739         }
1740 
1741         @Override
1742         public boolean isNullOrReference() {
1743             return true;
1744         }
1745 
1746         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1747         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1748             return v.visitTypeVariable(this, p);
1749         }
1750     }
1751 
1752     /** A captured type variable comes from wildcards which can have
1753      *  both upper and lower bound.  CapturedType extends TypeVar with
1754      *  a lower bound.
1755      */
1756     public static class CapturedType extends TypeVar {
1757 
1758         public WildcardType wildcard;
1759 
1760         @SuppressWarnings("this-escape")
1761         public CapturedType(Name name,
1762                             Symbol owner,
1763                             Type upper,
1764                             Type lower,
1765                             WildcardType wildcard) {
1766             super(name, owner, lower);
1767             this.lower = Assert.checkNonNull(lower);
1768             this.setUpperBound(upper);
1769             this.wildcard = wildcard;
1770         }
1771 
1772         public CapturedType(TypeSymbol tsym,
1773                             Type bound,
1774                             Type upper,
1775                             Type lower,
1776                             WildcardType wildcard,
1777                             List<TypeMetadata> metadata) {
1778             super(tsym, bound, lower, metadata);
1779             this.wildcard = wildcard;
1780         }
1781 
1782         @Override
1783         protected CapturedType cloneWithMetadata(List<TypeMetadata> md) {
1784             return new CapturedType(tsym, getUpperBound(), getUpperBound(), lower, wildcard, md) {
1785                 @Override
1786                 public Type baseType() { return CapturedType.this.baseType(); }
1787 
1788                 @Override @DefinedBy(Api.LANGUAGE_MODEL)
1789                 public Type getUpperBound() { return CapturedType.this.getUpperBound(); }
1790 
1791                 public void setUpperBound(Type bound) { CapturedType.this.setUpperBound(bound); }
1792             };
1793         }
1794 
1795         @Override
1796         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1797             return v.visitCapturedType(this, s);
1798         }
1799 
1800         @Override
1801         public boolean isCaptured() {
1802             return true;
1803         }
1804 
1805         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1806         public String toString() {
1807             StringBuilder sb = new StringBuilder();
1808             appendAnnotationsString(sb);
1809             sb.append("capture#");
1810             sb.append((hashCode() & 0xFFFFFFFFL) % Printer.PRIME);
1811             sb.append(" of ");
1812             sb.append(wildcard);
1813             return sb.toString();
1814         }
1815     }
1816 
1817     public abstract static class DelegatedType extends Type {
1818         public Type qtype;
1819         public TypeTag tag;
1820 
1821         public DelegatedType(TypeTag tag, Type qtype) {
1822             this(tag, qtype, List.nil());
1823         }
1824 
1825         public DelegatedType(TypeTag tag, Type qtype,
1826                              List<TypeMetadata> metadata) {
1827             super(qtype.tsym, metadata);
1828             this.tag = tag;
1829             this.qtype = qtype;
1830         }
1831 
1832         public TypeTag getTag() { return tag; }
1833         @DefinedBy(Api.LANGUAGE_MODEL)
1834         public String toString() { return qtype.toString(); }
1835         public List<Type> getTypeArguments() { return qtype.getTypeArguments(); }
1836         public Type getEnclosingType() { return qtype.getEnclosingType(); }
1837         public List<Type> getParameterTypes() { return qtype.getParameterTypes(); }
1838         public Type getReturnType() { return qtype.getReturnType(); }
1839         public Type getReceiverType() { return qtype.getReceiverType(); }
1840         public List<Type> getThrownTypes() { return qtype.getThrownTypes(); }
1841         public List<Type> allparams() { return qtype.allparams(); }
1842         public Type getUpperBound() { return qtype.getUpperBound(); }
1843         public boolean isErroneous() { return qtype.isErroneous(); }
1844     }
1845 
1846     /**
1847      * The type of a generic method type. It consists of a method type and
1848      * a list of method type-parameters that are used within the method
1849      * type.
1850      */
1851     public static class ForAll extends DelegatedType implements ExecutableType {
1852         public List<Type> tvars;
1853 
1854         public ForAll(List<Type> tvars, Type qtype) {
1855             super(FORALL, (MethodType)qtype);
1856             this.tvars = tvars;
1857         }
1858 
1859         @Override
1860         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1861             return v.visitForAll(this, s);
1862         }
1863 
1864         @DefinedBy(Api.LANGUAGE_MODEL)
1865         public String toString() {
1866             StringBuilder sb = new StringBuilder();
1867             appendAnnotationsString(sb);
1868             sb.append('<');
1869             sb.append(tvars);
1870             sb.append('>');
1871             sb.append(qtype);
1872             return sb.toString();
1873         }
1874 
1875         public List<Type> getTypeArguments()   { return tvars; }
1876 
1877         public boolean isErroneous()  {
1878             return qtype.isErroneous();
1879         }
1880 
1881         public boolean contains(Type elem) {
1882             return qtype.contains(elem);
1883         }
1884 
1885         public MethodType asMethodType() {
1886             return (MethodType)qtype;
1887         }
1888 
1889         public void complete() {
1890             for (List<Type> l = tvars; l.nonEmpty(); l = l.tail) {
1891                 ((TypeVar)l.head).getUpperBound().complete();
1892             }
1893             qtype.complete();
1894         }
1895 
1896         @DefinedBy(Api.LANGUAGE_MODEL)
1897         public List<TypeVar> getTypeVariables() {
1898             return List.convert(TypeVar.class, getTypeArguments());
1899         }
1900 
1901         @DefinedBy(Api.LANGUAGE_MODEL)
1902         public TypeKind getKind() {
1903             return TypeKind.EXECUTABLE;
1904         }
1905 
1906         @DefinedBy(Api.LANGUAGE_MODEL)
1907         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1908             return v.visitExecutable(this, p);
1909         }
1910     }
1911 
1912     /** A class for inference variables, for use during method/diamond type
1913      *  inference. An inference variable has upper/lower bounds and a set
1914      *  of equality constraints. Such bounds are set during subtyping, type-containment,
1915      *  type-equality checks, when the types being tested contain inference variables.
1916      *  A change listener can be attached to an inference variable, to receive notifications
1917      *  whenever the bounds of an inference variable change.
1918      */
1919     public static class UndetVar extends DelegatedType {
1920 
1921         enum Kind {
1922             NORMAL,
1923             CAPTURED,
1924             THROWS;
1925         }
1926 
1927         /** Inference variable change listener. The listener method is called
1928          *  whenever a change to the inference variable's bounds occurs
1929          */
1930         public interface UndetVarListener {
1931             /** called when some inference variable bounds (of given kinds ibs) change */
1932             void varBoundChanged(UndetVar uv, InferenceBound ib, Type bound, boolean update);
1933             /** called when the inferred type is set on some inference variable */
1934             default void varInstantiated(UndetVar uv) { Assert.error(); }
1935         }
1936 
1937         /**
1938          * Inference variable bound kinds
1939          */
1940         public enum InferenceBound {
1941             /** lower bounds */
1942             LOWER {
1943                 public InferenceBound complement() { return UPPER; }
1944             },
1945             /** equality constraints */
1946             EQ {
1947                 public InferenceBound complement() { return EQ; }
1948             },
1949             /** upper bounds */
1950             UPPER {
1951                 public InferenceBound complement() { return LOWER; }
1952             };
1953 
1954             public abstract InferenceBound complement();
1955 
1956             public boolean lessThan(InferenceBound that) {
1957                 if (that == this) {
1958                     return false;
1959                 } else {
1960                     switch (that) {
1961                         case UPPER: return true;
1962                         case LOWER: return false;
1963                         case EQ: return (this != UPPER);
1964                         default:
1965                             Assert.error("Cannot get here!");
1966                             return false;
1967                     }
1968                 }
1969             }
1970         }
1971 
1972         /** list of incorporation actions (used by the incorporation engine). */
1973         public ArrayDeque<IncorporationAction> incorporationActions = new ArrayDeque<>();
1974 
1975         /** inference variable bounds */
1976         protected Map<InferenceBound, List<Type>> bounds;
1977 
1978         /** inference variable's inferred type (set from Infer.java) */
1979         private Type inst = null;
1980 
1981         /** number of declared (upper) bounds */
1982         public int declaredCount;
1983 
1984         /** inference variable's change listener */
1985         public UndetVarListener listener = null;
1986 
1987         Kind kind;
1988 
1989         @Override
1990         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1991             return v.visitUndetVar(this, s);
1992         }
1993 
1994         @SuppressWarnings("this-escape")
1995         public UndetVar(TypeVar origin, UndetVarListener listener, Types types) {
1996             // This is a synthesized internal type, so we cannot annotate it.
1997             super(UNDETVAR, origin);
1998             this.kind = origin.isCaptured() ?
1999                     Kind.CAPTURED :
2000                     Kind.NORMAL;
2001             this.listener = listener;
2002             bounds = new EnumMap<>(InferenceBound.class);
2003             List<Type> declaredBounds = types.getBounds(origin);
2004             declaredCount = declaredBounds.length();
2005             bounds.put(InferenceBound.UPPER, List.nil());
2006             bounds.put(InferenceBound.LOWER, List.nil());
2007             bounds.put(InferenceBound.EQ, List.nil());
2008             for (Type t : declaredBounds.reverse()) {
2009                 //add bound works in reverse order
2010                 addBound(InferenceBound.UPPER, t, types, true);
2011             }
2012             if (origin.isCaptured() && !origin.lower.hasTag(BOT)) {
2013                 //add lower bound if needed
2014                 addBound(InferenceBound.LOWER, origin.lower, types, true);
2015             }
2016         }
2017 
2018         @DefinedBy(Api.LANGUAGE_MODEL)
2019         public String toString() {
2020             StringBuilder sb = new StringBuilder();
2021             appendAnnotationsString(sb);
2022             if (inst == null) {
2023                 sb.append(qtype);
2024                 sb.append('?');
2025             } else {
2026                 sb.append(inst);
2027             }
2028             return sb.toString();
2029         }
2030 
2031         public String debugString() {
2032             String result = "inference var = " + qtype + "\n";
2033             if (inst != null) {
2034                 result += "inst = " + inst + '\n';
2035             }
2036             for (InferenceBound bound: InferenceBound.values()) {
2037                 List<Type> aboundList = bounds.get(bound);
2038                 if (aboundList != null && aboundList.size() > 0) {
2039                     result += bound + " = " + aboundList + '\n';
2040                 }
2041             }
2042             return result;
2043         }
2044 
2045         public void setThrow() {
2046             if (this.kind == Kind.CAPTURED) {
2047                 //invalid state transition
2048                 throw new IllegalStateException();
2049             }
2050             this.kind = Kind.THROWS;
2051         }
2052 
2053         public void setNormal() {
2054             Assert.check(this.kind == Kind.CAPTURED);
2055             this.kind = Kind.NORMAL;
2056         }
2057 
2058         /**
2059          * Returns a new copy of this undet var.
2060          */
2061         public UndetVar dup(Types types) {
2062             UndetVar uv2 = new UndetVar((TypeVar)qtype, listener, types);
2063             dupTo(uv2, types);
2064             return uv2;
2065         }
2066 
2067         /**
2068          * Dumps the contents of this undet var on another undet var.
2069          */
2070         public void dupTo(UndetVar uv2, Types types) {
2071             uv2.listener = null;
2072             uv2.bounds.clear();
2073             for (InferenceBound ib : InferenceBound.values()) {
2074                 uv2.bounds.put(ib, List.nil());
2075                 for (Type t : getBounds(ib)) {
2076                     uv2.addBound(ib, t, types, true);
2077                 }
2078             }
2079             uv2.inst = inst;
2080             uv2.listener = listener;
2081             uv2.incorporationActions = new ArrayDeque<>();
2082             for (IncorporationAction action : incorporationActions) {
2083                 uv2.incorporationActions.add(action.dup(uv2));
2084             }
2085             uv2.kind = kind;
2086         }
2087 
2088         @Override
2089         public boolean isPartial() {
2090             return true;
2091         }
2092 
2093         @Override
2094         public Type baseType() {
2095             return (inst == null) ? this : inst.baseType();
2096         }
2097 
2098         public Type getInst() {
2099             return inst;
2100         }
2101 
2102         public void setInst(Type inst) {
2103             this.inst = inst;
2104             if (listener != null) {
2105                 listener.varInstantiated(this);
2106             }
2107         }
2108 
2109         /** get all bounds of a given kind */
2110         public List<Type> getBounds(InferenceBound... ibs) {
2111             ListBuffer<Type> buf = new ListBuffer<>();
2112             for (InferenceBound ib : ibs) {
2113                 buf.appendList(bounds.get(ib));
2114             }
2115             return buf.toList();
2116         }
2117 
2118         /** get the list of declared (upper) bounds */
2119         public List<Type> getDeclaredBounds() {
2120             ListBuffer<Type> buf = new ListBuffer<>();
2121             int count = 0;
2122             for (Type b : getBounds(InferenceBound.UPPER)) {
2123                 if (count++ == declaredCount) break;
2124                 buf.append(b);
2125             }
2126             return buf.toList();
2127         }
2128 
2129         /** internal method used to override an undetvar bounds */
2130         public void setBounds(InferenceBound ib, List<Type> newBounds) {
2131             bounds.put(ib, newBounds);
2132         }
2133 
2134         /** add a bound of a given kind - this might trigger listener notification */
2135         public final void addBound(InferenceBound ib, Type bound, Types types) {
2136             addBound(ib, bound, types, false);
2137         }
2138 
2139         private void addBound(InferenceBound ib, Type bound, Types types, boolean update) {
2140             if (kind == Kind.CAPTURED && !update) {
2141                 //Captured inference variables bounds must not be updated during incorporation,
2142                 //except when some inference variable (beta) has been instantiated in the
2143                 //right-hand-side of a 'C<alpha> = capture(C<? extends/super beta>) constraint.
2144                 if (bound.hasTag(UNDETVAR) && !((UndetVar)bound).isCaptured()) {
2145                     //If the new incoming bound is itself a (regular) inference variable,
2146                     //then we are allowed to propagate this inference variable bounds to it.
2147                     ((UndetVar)bound).addBound(ib.complement(), this, types, false);
2148                 }
2149             } else {
2150                 Type bound2 = bound.map(toTypeVarMap).baseType();
2151                 List<Type> prevBounds = bounds.get(ib);
2152                 if (bound == qtype) return;
2153                 for (Type b : prevBounds) {
2154                     //check for redundancy - do not add same bound twice
2155                     if (types.isSameType(b, bound2)) return;
2156                 }
2157                 bounds.put(ib, prevBounds.prepend(bound2));
2158                 notifyBoundChange(ib, bound2, false);
2159             }
2160         }
2161         //where
2162             TypeMapping<Void> toTypeVarMap = new StructuralTypeMapping<Void>() {
2163                 @Override
2164                 public Type visitUndetVar(UndetVar uv, Void _unused) {
2165                     return uv.inst != null ? uv.inst : uv.qtype;
2166                 }
2167             };
2168 
2169         /** replace types in all bounds - this might trigger listener notification */
2170         public void substBounds(List<Type> from, List<Type> to, Types types) {
2171             final ListBuffer<Pair<InferenceBound, Type>>  boundsChanged = new ListBuffer<>();
2172             UndetVarListener prevListener = listener;
2173             try {
2174                 //setup new listener for keeping track of changed bounds
2175                 listener = (uv, ib, t, _ignored) -> {
2176                     Assert.check(uv == UndetVar.this);
2177                     boundsChanged.add(new Pair<>(ib, t));
2178                 };
2179                 for (Map.Entry<InferenceBound, List<Type>> _entry : bounds.entrySet()) {
2180                     InferenceBound ib = _entry.getKey();
2181                     List<Type> prevBounds = _entry.getValue();
2182                     ListBuffer<Type> newBounds = new ListBuffer<>();
2183                     ListBuffer<Type> deps = new ListBuffer<>();
2184                     //step 1 - re-add bounds that are not dependent on ivars
2185                     for (Type t : prevBounds) {
2186                         if (!t.containsAny(from)) {
2187                             newBounds.append(t);
2188                         } else {
2189                             deps.append(t);
2190                         }
2191                     }
2192                     //step 2 - replace bounds
2193                     bounds.put(ib, newBounds.toList());
2194                     //step 3 - for each dependency, add new replaced bound
2195                     for (Type dep : deps) {
2196                         addBound(ib, types.subst(dep, from, to), types, true);
2197                     }
2198                 }
2199             } finally {
2200                 listener = prevListener;
2201                 for (Pair<InferenceBound, Type> boundUpdate : boundsChanged) {
2202                     notifyBoundChange(boundUpdate.fst, boundUpdate.snd, true);
2203                 }
2204             }
2205         }
2206 
2207         private void notifyBoundChange(InferenceBound ib, Type bound, boolean update) {
2208             if (listener != null) {
2209                 listener.varBoundChanged(this, ib, bound, update);
2210             }
2211         }
2212 
2213         public final boolean isCaptured() {
2214             return kind == Kind.CAPTURED;
2215         }
2216 
2217         public final boolean isThrows() {
2218             return kind == Kind.THROWS;
2219         }
2220     }
2221 
2222     /** Represents NONE.
2223      */
2224     public static class JCNoType extends Type implements NoType {
2225         public JCNoType() {
2226             // Need to use List.nil(), because JCNoType constructor
2227             // gets called in static initializers in Type, where
2228             // noAnnotations is also defined.
2229             super(null, List.nil());
2230         }
2231 
2232         @Override
2233         public TypeTag getTag() {
2234             return NONE;
2235         }
2236 
2237         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2238         public TypeKind getKind() {
2239             return TypeKind.NONE;
2240         }
2241 
2242         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2243         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
2244             return v.visitNoType(this, p);
2245         }
2246 
2247         @Override
2248         public boolean isCompound() { return false; }
2249     }
2250 
2251     /** Represents VOID.
2252      */
2253     public static class JCVoidType extends Type implements NoType {
2254 
2255         public JCVoidType() {
2256             // Void cannot be annotated
2257             super(null, List.nil());
2258         }
2259 
2260         @Override
2261         public TypeTag getTag() {
2262             return VOID;
2263         }
2264 
2265         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2266         public TypeKind getKind() {
2267             return TypeKind.VOID;
2268         }
2269 
2270         @Override
2271         public boolean isCompound() { return false; }
2272 
2273         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2274         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
2275             return v.visitNoType(this, p);
2276         }
2277 
2278         @Override
2279         public boolean isPrimitiveOrVoid() {
2280             return true;
2281         }
2282     }
2283 
2284     static class BottomType extends Type implements NullType {
2285         public BottomType() {
2286             // Bottom is a synthesized internal type, so it cannot be annotated
2287             super(null, List.nil());
2288         }
2289 
2290         @Override
2291         public TypeTag getTag() {
2292             return BOT;
2293         }
2294 
2295         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2296         public TypeKind getKind() {
2297             return TypeKind.NULL;
2298         }
2299 
2300         @Override
2301         public boolean isCompound() { return false; }
2302 
2303         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2304         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
2305             return v.visitNull(this, p);
2306         }
2307 
2308         @Override
2309         public Type constType(Object value) {
2310             return this;
2311         }
2312 
2313         @Override
2314         public String stringValue() {
2315             return "null";
2316         }
2317 
2318         @Override
2319         public boolean isNullOrReference() {
2320             return true;
2321         }
2322 
2323     }
2324 
2325     public static class ErrorType extends ClassType
2326             implements javax.lang.model.type.ErrorType {
2327 
2328         private Type originalType = null;
2329 
2330         public ErrorType(ClassSymbol c, Type originalType) {
2331             this(originalType, c);
2332             c.type = this;
2333             c.kind = ERR;
2334             c.members_field = new Scope.ErrorScope(c);
2335         }
2336 
2337         public ErrorType(Type originalType, TypeSymbol tsym) {
2338             super(noType, List.nil(), null);
2339             this.tsym = tsym;
2340             this.originalType = (originalType == null ? noType : originalType);
2341         }
2342 
2343         public ErrorType(Type originalType, TypeSymbol tsym,
2344                           List<TypeMetadata> metadata) {
2345             super(noType, List.nil(), null, metadata);
2346             this.tsym = tsym;
2347             this.originalType = (originalType == null ? noType : originalType);
2348         }
2349 
2350         @Override
2351         protected ErrorType cloneWithMetadata(List<TypeMetadata> md) {
2352             return new ErrorType(originalType, tsym, md) {
2353                 @Override
2354                 public Type baseType() { return ErrorType.this.baseType(); }
2355             };
2356         }
2357 
2358         @Override
2359         public TypeTag getTag() {
2360             return ERROR;
2361         }
2362 
2363         @Override
2364         public boolean isPartial() {
2365             return true;
2366         }
2367 
2368         @Override
2369         public boolean isReference() {
2370             return true;
2371         }
2372 
2373         @Override
2374         public boolean isNullOrReference() {
2375             return true;
2376         }
2377 
2378         public ErrorType(Name name, TypeSymbol container, Type originalType) {
2379             this(new ClassSymbol(PUBLIC|STATIC|ACYCLIC, name, null, container), originalType);
2380         }
2381 
2382         @Override
2383         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
2384             return v.visitErrorType(this, s);
2385         }
2386 
2387         public Type constType(Object constValue) { return this; }
2388         @DefinedBy(Api.LANGUAGE_MODEL)
2389         public Type getEnclosingType()           { return Type.noType; }
2390         public Type getReturnType()              { return this; }
2391         public Type asSub(Symbol sym)            { return this; }
2392 
2393         public boolean isGenType(Type t)         { return true; }
2394         public boolean isErroneous()             { return true; }
2395         public boolean isCompound()              { return false; }
2396         public boolean isInterface()             { return false; }
2397 
2398         @DefinedBy(Api.LANGUAGE_MODEL)
2399         public TypeKind getKind() {
2400             return TypeKind.ERROR;
2401         }
2402 
2403         public Type getOriginalType() {
2404             return originalType;
2405         }
2406 
2407         @DefinedBy(Api.LANGUAGE_MODEL)
2408         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
2409             return v.visitError(this, p);
2410         }
2411     }
2412 
2413     /**
2414      * A visitor for types.  A visitor is used to implement operations
2415      * (or relations) on types.  Most common operations on types are
2416      * binary relations and this interface is designed for binary
2417      * relations, that is, operations of the form
2418      * Type&nbsp;&times;&nbsp;S&nbsp;&rarr;&nbsp;R.
2419      * <!-- In plain text: Type x S -> R -->
2420      *
2421      * @param <R> the return type of the operation implemented by this
2422      * visitor; use Void if no return type is needed.
2423      * @param <S> the type of the second argument (the first being the
2424      * type itself) of the operation implemented by this visitor; use
2425      * Void if a second argument is not needed.
2426      */
2427     public interface Visitor<R,S> {
2428         R visitClassType(ClassType t, S s);
2429         R visitWildcardType(WildcardType t, S s);
2430         R visitArrayType(ArrayType t, S s);
2431         R visitMethodType(MethodType t, S s);
2432         R visitPackageType(PackageType t, S s);
2433         R visitModuleType(ModuleType t, S s);
2434         R visitTypeVar(TypeVar t, S s);
2435         R visitCapturedType(CapturedType t, S s);
2436         R visitForAll(ForAll t, S s);
2437         R visitUndetVar(UndetVar t, S s);
2438         R visitErrorType(ErrorType t, S s);
2439         R visitType(Type t, S s);
2440     }
2441 }