1 /*
   2  * Copyright (c) 1999, 2022, 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.function.Predicate;
  34 
  35 import javax.lang.model.type.*;
  36 
  37 import com.sun.tools.javac.code.Symbol.*;
  38 import com.sun.tools.javac.code.TypeMetadata.Entry;
  39 import com.sun.tools.javac.code.Types.TypeMapping;
  40 import com.sun.tools.javac.code.Types.UniqueType;
  41 import com.sun.tools.javac.comp.Infer.IncorporationAction;
  42 import com.sun.tools.javac.jvm.ClassFile;
  43 import com.sun.tools.javac.jvm.PoolConstant;
  44 import com.sun.tools.javac.util.*;
  45 import com.sun.tools.javac.util.DefinedBy.Api;
  46 
  47 import static com.sun.tools.javac.code.BoundKind.*;
  48 import static com.sun.tools.javac.code.Flags.*;
  49 import static com.sun.tools.javac.code.Kinds.Kind.*;
  50 import static com.sun.tools.javac.code.TypeTag.*;
  51 
  52 /** This class represents Java types. The class itself defines the behavior of
  53  *  the following types:
  54  *  <pre>
  55  *  base types (tags: BYTE, CHAR, SHORT, INT, LONG, FLOAT, DOUBLE, BOOLEAN),
  56  *  type `void' (tag: VOID),
  57  *  the bottom type (tag: BOT),
  58  *  the missing type (tag: NONE).
  59  *  </pre>
  60  *  <p>The behavior of the following types is defined in subclasses, which are
  61  *  all static inner classes of this class:
  62  *  <pre>
  63  *  class types (tag: CLASS, class: ClassType),
  64  *  array types (tag: ARRAY, class: ArrayType),
  65  *  method types (tag: METHOD, class: MethodType),
  66  *  package types (tag: PACKAGE, class: PackageType),
  67  *  type variables (tag: TYPEVAR, class: TypeVar),
  68  *  type arguments (tag: WILDCARD, class: WildcardType),
  69  *  generic method types (tag: FORALL, class: ForAll),
  70  *  the error type (tag: ERROR, class: ErrorType).
  71  *  </pre>
  72  *
  73  *  <p><b>This is NOT part of any supported API.
  74  *  If you write code that depends on this, you do so at your own risk.
  75  *  This code and its internal interfaces are subject to change or
  76  *  deletion without notice.</b>
  77  *
  78  *  @see TypeTag
  79  */
  80 public abstract class Type extends AnnoConstruct implements TypeMirror, PoolConstant {
  81 
  82     /**
  83      * Type metadata,  Should be {@code null} for the default value.
  84      *
  85      * Note: it is an invariant that for any {@code TypeMetadata}
  86      * class, a given {@code Type} may have at most one metadata array
  87      * entry of that class.
  88      */
  89     protected final TypeMetadata metadata;
  90 
  91     public TypeMetadata getMetadata() {
  92         return metadata;
  93     }
  94 
  95     public Entry getMetadataOfKind(final Entry.Kind kind) {
  96         return metadata != null ? metadata.get(kind) : null;
  97     }
  98 
  99     /** Constant type: no type at all. */
 100     public static final JCNoType noType = new JCNoType() {
 101         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 102         public String toString() {
 103             return "none";
 104         }
 105     };
 106 
 107     /** Constant type: special type to be used during recovery of deferred expressions. */
 108     public static final JCNoType recoveryType = new JCNoType(){
 109         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 110         public String toString() {
 111             return "recovery";
 112         }
 113     };
 114 
 115     /** Constant type: special type to be used for marking stuck trees. */
 116     public static final JCNoType stuckType = new JCNoType() {
 117         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 118         public String toString() {
 119             return "stuck";
 120         }
 121     };
 122 
 123     /** If this switch is turned on, the names of type variables
 124      *  and anonymous classes are printed with hashcodes appended.
 125      */
 126     public static boolean moreInfo = false;
 127 
 128     /** The defining class / interface / package / type variable.
 129      */
 130     public TypeSymbol tsym;
 131 
 132     @Override
 133     public int poolTag() {
 134         throw new AssertionError("Invalid pool entry");
 135     }
 136 
 137     @Override
 138     public Object poolKey(Types types) {
 139         return new UniqueType(this, types);
 140     }
 141 
 142     /**
 143      * Checks if the current type tag is equal to the given tag.
 144      * @return true if tag is equal to the current type tag.
 145      */
 146     public boolean hasTag(TypeTag tag) {
 147         return tag == getTag();
 148     }
 149 
 150     /**
 151      * Returns the current type tag.
 152      * @return the value of the current type tag.
 153      */
 154     public abstract TypeTag getTag();
 155 
 156     public boolean isNumeric() {
 157         return false;
 158     }
 159 
 160     public boolean isIntegral() {
 161         return false;
 162     }
 163 
 164     public boolean isPrimitive() {
 165         return false;
 166     }
 167 
 168     public boolean isPrimitiveOrVoid() {
 169         return false;
 170     }
 171 
 172     public boolean isReference() {
 173         return false;
 174     }
 175 
 176     public boolean isNullOrReference() {
 177         return false;
 178     }
 179 
 180     public boolean isPartial() {
 181         return false;
 182     }
 183 
 184     /**
 185      * The constant value of this type, null if this type does not
 186      * have a constant value attribute. Only primitive types and
 187      * strings (ClassType) can have a constant value attribute.
 188      * @return the constant value attribute of this type
 189      */
 190     public Object constValue() {
 191         return null;
 192     }
 193 
 194     /** Is this a constant type whose value is false?
 195      */
 196     public boolean isFalse() {
 197         return false;
 198     }
 199 
 200     /** Is this a constant type whose value is true?
 201      */
 202     public boolean isTrue() {
 203         return false;
 204     }
 205 
 206     /**
 207      * Get the representation of this type used for modelling purposes.
 208      * By default, this is itself. For ErrorType, a different value
 209      * may be provided.
 210      */
 211     public Type getModelType() {
 212         return this;
 213     }
 214 
 215     public static List<Type> getModelTypes(List<Type> ts) {
 216         ListBuffer<Type> lb = new ListBuffer<>();
 217         for (Type t: ts)
 218             lb.append(t.getModelType());
 219         return lb.toList();
 220     }
 221 
 222     /**For ErrorType, returns the original type, otherwise returns the type itself.
 223      */
 224     public Type getOriginalType() {
 225         return this;
 226     }
 227 
 228     public <R,S> R accept(Type.Visitor<R,S> v, S s) { return v.visitType(this, s); }
 229 
 230     /** Define a type given its tag, type symbol, and type annotations
 231      */
 232 
 233     public Type(TypeSymbol tsym, TypeMetadata metadata) {
 234         Assert.checkNonNull(metadata);
 235         this.tsym = tsym;
 236         this.metadata = metadata;
 237     }
 238 
 239     /**
 240      * A subclass of {@link Types.TypeMapping} which applies a mapping recursively to the subterms
 241      * of a given type expression. This mapping returns the original type is no changes occurred
 242      * when recursively mapping the original type's subterms.
 243      */
 244     public abstract static class StructuralTypeMapping<S> extends Types.TypeMapping<S> {
 245 
 246         @Override
 247         public Type visitClassType(ClassType t, S s) {
 248             Type outer = t.getEnclosingType();
 249             Type outer1 = visit(outer, s);
 250             List<Type> typarams = t.getTypeArguments();
 251             List<Type> typarams1 = visit(typarams, s);
 252             if (outer1 == outer && typarams1 == typarams) return t;
 253             else return new ClassType(outer1, typarams1, t.tsym, t.metadata) {
 254                 @Override
 255                 protected boolean needsStripping() {
 256                     return true;
 257                 }
 258             };
 259         }
 260 
 261         @Override
 262         public Type visitWildcardType(WildcardType wt, S s) {
 263             Type t = wt.type;
 264             if (t != null)
 265                 t = visit(t, s);
 266             if (t == wt.type)
 267                 return wt;
 268             else
 269                 return new WildcardType(t, wt.kind, wt.tsym, wt.bound, wt.metadata) {
 270                     @Override
 271                     protected boolean needsStripping() {
 272                         return true;
 273                     }
 274                 };
 275         }
 276 
 277         @Override
 278         public Type visitArrayType(ArrayType t, S s) {
 279             Type elemtype = t.elemtype;
 280             Type elemtype1 = visit(elemtype, s);
 281             if (elemtype1 == elemtype) return t;
 282             else return new ArrayType(elemtype1, t.tsym, t.metadata) {
 283                 @Override
 284                 protected boolean needsStripping() {
 285                     return true;
 286                 }
 287             };
 288         }
 289 
 290         @Override
 291         public Type visitMethodType(MethodType t, S s) {
 292             List<Type> argtypes = t.argtypes;
 293             Type restype = t.restype;
 294             List<Type> thrown = t.thrown;
 295             List<Type> argtypes1 = visit(argtypes, s);
 296             Type restype1 = visit(restype, s);
 297             List<Type> thrown1 = visit(thrown, s);
 298             if (argtypes1 == argtypes &&
 299                 restype1 == restype &&
 300                 thrown1 == thrown) return t;
 301             else return new MethodType(argtypes1, restype1, thrown1, t.tsym) {
 302                 @Override
 303                 protected boolean needsStripping() {
 304                     return true;
 305                 }
 306             };
 307         }
 308 
 309         @Override
 310         public Type visitForAll(ForAll t, S s) {
 311             return visit(t.qtype, s);
 312         }
 313     }
 314 
 315     /** map a type function over all immediate descendants of this type
 316      */
 317     public <Z> Type map(TypeMapping<Z> mapping, Z arg) {
 318         return mapping.visit(this, arg);
 319     }
 320 
 321     /** map a type function over all immediate descendants of this type (no arg version)
 322      */
 323     public <Z> Type map(TypeMapping<Z> mapping) {
 324         return mapping.visit(this, null);
 325     }
 326 
 327     /** Define a constant type, of the same kind as this type
 328      *  and with given constant value
 329      */
 330     public Type constType(Object constValue) {
 331         throw new AssertionError();
 332     }
 333 
 334     /**
 335      * If this is a constant type, return its underlying type.
 336      * Otherwise, return the type itself.
 337      */
 338     public Type baseType() {
 339         return this;
 340     }
 341 
 342     /**
 343      * Returns the original version of this type, before metadata were added. This routine is meant
 344      * for internal use only (i.e. {@link Type#equalsIgnoreMetadata(Type)}, {@link Type#stripMetadata});
 345      * it should not be used outside this class.
 346      */
 347     protected Type typeNoMetadata() {
 348         return metadata == TypeMetadata.EMPTY ? this : baseType();
 349     }
 350 
 351     /**
 352      * Create a new copy of this type but with the specified TypeMetadata.
 353      */
 354     public abstract Type cloneWithMetadata(TypeMetadata metadata);
 355 
 356     /**
 357      * Does this type require annotation stripping for API clients?
 358      */
 359     protected boolean needsStripping() {
 360         return false;
 361     }
 362 
 363     /**
 364      * Strip all metadata associated with this type - this could return a new clone of the type.
 365      * This routine is only used to present the correct annotated types back to the users when types
 366      * are accessed through compiler APIs; it should not be used anywhere in the compiler internals
 367      * as doing so might result in performance penalties.
 368      */
 369     public Type stripMetadataIfNeeded() {
 370         return needsStripping() ?
 371                 accept(stripMetadata, null) :
 372                 this;
 373     }
 374 
 375     public Type stripMetadata() {
 376         return accept(stripMetadata, null);
 377     }
 378     //where
 379         private static final TypeMapping<Void> stripMetadata = new StructuralTypeMapping<Void>() {
 380             @Override
 381             public Type visitClassType(ClassType t, Void aVoid) {
 382                 return super.visitClassType((ClassType)t.typeNoMetadata(), aVoid);
 383             }
 384 
 385             @Override
 386             public Type visitArrayType(ArrayType t, Void aVoid) {
 387                 return super.visitArrayType((ArrayType)t.typeNoMetadata(), aVoid);
 388             }
 389 
 390             @Override
 391             public Type visitTypeVar(TypeVar t, Void aVoid) {
 392                 return super.visitTypeVar((TypeVar)t.typeNoMetadata(), aVoid);
 393             }
 394 
 395             @Override
 396             public Type visitWildcardType(WildcardType wt, Void aVoid) {
 397                 return super.visitWildcardType((WildcardType)wt.typeNoMetadata(), aVoid);
 398             }
 399         };
 400 
 401     public Type annotatedType(final List<Attribute.TypeCompound> annos) {
 402         final Entry annoMetadata = new TypeMetadata.Annotations(annos);
 403         return cloneWithMetadata(metadata.combine(annoMetadata));
 404     }
 405 
 406     public boolean isAnnotated() {
 407         final TypeMetadata.Annotations metadata =
 408             (TypeMetadata.Annotations)getMetadataOfKind(Entry.Kind.ANNOTATIONS);
 409 
 410         return null != metadata && !metadata.getAnnotations().isEmpty();
 411     }
 412 
 413     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 414     public List<Attribute.TypeCompound> getAnnotationMirrors() {
 415         final TypeMetadata.Annotations metadata =
 416             (TypeMetadata.Annotations)getMetadataOfKind(Entry.Kind.ANNOTATIONS);
 417 
 418         return metadata == null ? List.nil() : metadata.getAnnotations();
 419     }
 420 
 421 
 422     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 423     public <A extends Annotation> A getAnnotation(Class<A> annotationType) {
 424         return null;
 425     }
 426 
 427 
 428     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 429     public <A extends Annotation> A[] getAnnotationsByType(Class<A> annotationType) {
 430         @SuppressWarnings("unchecked")
 431         A[] tmp = (A[]) java.lang.reflect.Array.newInstance(annotationType, 0);
 432         return tmp;
 433     }
 434 
 435     /** Return the base types of a list of types.
 436      */
 437     public static List<Type> baseTypes(List<Type> ts) {
 438         if (ts.nonEmpty()) {
 439             Type t = ts.head.baseType();
 440             List<Type> baseTypes = baseTypes(ts.tail);
 441             if (t != ts.head || baseTypes != ts.tail)
 442                 return baseTypes.prepend(t);
 443         }
 444         return ts;
 445     }
 446 
 447     protected void appendAnnotationsString(StringBuilder sb,
 448                                          boolean prefix) {
 449         if (isAnnotated()) {
 450             if (prefix) {
 451                 sb.append(" ");
 452             }
 453             sb.append(getAnnotationMirrors());
 454             sb.append(" ");
 455         }
 456     }
 457 
 458     protected void appendAnnotationsString(StringBuilder sb) {
 459         appendAnnotationsString(sb, false);
 460     }
 461 
 462     /** The Java source which this type represents.
 463      */
 464     @DefinedBy(Api.LANGUAGE_MODEL)
 465     public String toString() {
 466         StringBuilder sb = new StringBuilder();
 467         appendAnnotationsString(sb);
 468         if (tsym == null || tsym.name == null) {
 469             sb.append("<none>");
 470         } else {
 471             sb.append(tsym.name.toString());
 472         }
 473         if (moreInfo && hasTag(TYPEVAR)) {
 474             sb.append(hashCode());
 475         }
 476         return sb.toString();
 477     }
 478 
 479     /**
 480      * The Java source which this type list represents.  A List is
 481      * represented as a comma-separated listing of the elements in
 482      * that list.
 483      */
 484     public static String toString(List<Type> ts) {
 485         if (ts.isEmpty()) {
 486             return "";
 487         } else {
 488             StringBuilder buf = new StringBuilder();
 489             buf.append(ts.head.toString());
 490             for (List<Type> l = ts.tail; l.nonEmpty(); l = l.tail)
 491                 buf.append(",").append(l.head.toString());
 492             return buf.toString();
 493         }
 494     }
 495 
 496     /**
 497      * The constant value of this type, converted to String
 498      */
 499     public String stringValue() {
 500         Object cv = Assert.checkNonNull(constValue());
 501         return cv.toString();
 502     }
 503 
 504     /**
 505      * Override this method with care. For most Type instances this should behave as ==.
 506      */
 507     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 508     public boolean equals(Object t) {
 509         return this == t;
 510     }
 511 
 512     public boolean equalsIgnoreMetadata(Type t) {
 513         return typeNoMetadata().equals(t.typeNoMetadata());
 514     }
 515 
 516     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 517     public int hashCode() {
 518         return super.hashCode();
 519     }
 520 
 521     public String argtypes(boolean varargs) {
 522         List<Type> args = getParameterTypes();
 523         if (!varargs) return args.toString();
 524         StringBuilder buf = new StringBuilder();
 525         while (args.tail.nonEmpty()) {
 526             buf.append(args.head);
 527             args = args.tail;
 528             buf.append(',');
 529         }
 530         if (args.head.hasTag(ARRAY)) {
 531             buf.append(((ArrayType)args.head).elemtype);
 532             if (args.head.getAnnotationMirrors().nonEmpty()) {
 533                 buf.append(args.head.getAnnotationMirrors());
 534             }
 535             buf.append("...");
 536         } else {
 537             buf.append(args.head);
 538         }
 539         return buf.toString();
 540     }
 541 
 542     /** Access methods.
 543      */
 544     public List<Type>        getTypeArguments()  { return List.nil(); }
 545     public Type              getEnclosingType()  { return null; }
 546     public List<Type>        getParameterTypes() { return List.nil(); }
 547     public Type              getReturnType()     { return null; }
 548     public Type              getReceiverType()   { return null; }
 549     public List<Type>        getThrownTypes()    { return List.nil(); }
 550     public Type              getUpperBound()     { return null; }
 551     public Type              getLowerBound()     { return null; }
 552 
 553     /** Navigation methods, these will work for classes, type variables,
 554      *  foralls, but will return null for arrays and methods.
 555      */
 556 
 557    /** Return all parameters of this type and all its outer types in order
 558     *  outer (first) to inner (last).
 559     */
 560     public List<Type> allparams() { return List.nil(); }
 561 
 562     /** Does this type contain "error" elements?
 563      */
 564     public boolean isErroneous() {
 565         return false;
 566     }
 567 
 568     public static boolean isErroneous(List<Type> ts) {
 569         for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
 570             if (l.head.isErroneous()) return true;
 571         return false;
 572     }
 573 
 574     /** Is this type parameterized?
 575      *  A class type is parameterized if it has some parameters.
 576      *  An array type is parameterized if its element type is parameterized.
 577      *  All other types are not parameterized.
 578      */
 579     public boolean isParameterized() {
 580         return false;
 581     }
 582 
 583     /** Is this type a raw type?
 584      *  A class type is a raw type if it misses some of its parameters.
 585      *  An array type is a raw type if its element type is raw.
 586      *  All other types are not raw.
 587      *  Type validation will ensure that the only raw types
 588      *  in a program are types that miss all their type variables.
 589      */
 590     public boolean isRaw() {
 591         return false;
 592     }
 593 
 594     /**
 595      * A compound type is a special class type whose supertypes are used to store a list
 596      * of component types. There are two kinds of compound types: (i) intersection types
 597      * {@see IntersectionClassType} and (ii) union types {@see UnionClassType}.
 598      */
 599     public boolean isCompound() {
 600         return false;
 601     }
 602 
 603     public boolean isIntersection() {
 604         return false;
 605     }
 606 
 607     public boolean isUnion() {
 608         return false;
 609     }
 610 
 611     public boolean isInterface() {
 612         return (tsym.flags() & INTERFACE) != 0;
 613     }
 614 
 615     public boolean isFinal() {
 616         return (tsym.flags() & FINAL) != 0;
 617     }
 618 
 619     /**
 620      * Does this type contain occurrences of type t?
 621      */
 622     public boolean contains(Type t) {
 623         return t.equalsIgnoreMetadata(this);
 624     }
 625 
 626     public static boolean contains(List<Type> ts, Type t) {
 627         for (List<Type> l = ts;
 628              l.tail != null /*inlined: l.nonEmpty()*/;
 629              l = l.tail)
 630             if (l.head.contains(t)) return true;
 631         return false;
 632     }
 633 
 634     /** Does this type contain an occurrence of some type in 'ts'?
 635      */
 636     public boolean containsAny(List<Type> ts) {
 637         for (Type t : ts)
 638             if (this.contains(t)) return true;
 639         return false;
 640     }
 641 
 642     public static boolean containsAny(List<Type> ts1, List<Type> ts2) {
 643         for (Type t : ts1)
 644             if (t.containsAny(ts2)) return true;
 645         return false;
 646     }
 647 
 648     public static List<Type> filter(List<Type> ts, Predicate<Type> tf) {
 649         ListBuffer<Type> buf = new ListBuffer<>();
 650         for (Type t : ts) {
 651             if (tf.test(t)) {
 652                 buf.append(t);
 653             }
 654         }
 655         return buf.toList();
 656     }
 657 
 658     public boolean isSuperBound() { return false; }
 659     public boolean isExtendsBound() { return false; }
 660     public boolean isUnbound() { return false; }
 661     public Type withTypeVar(Type t) { return this; }
 662 
 663     /** The underlying method type of this type.
 664      */
 665     public MethodType asMethodType() { throw new AssertionError(); }
 666 
 667     /** Complete loading all classes in this type.
 668      */
 669     public void complete() {}
 670 
 671     public TypeSymbol asElement() {
 672         return tsym;
 673     }
 674 
 675     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 676     public TypeKind getKind() {
 677         return TypeKind.OTHER;
 678     }
 679 
 680     @Override @DefinedBy(Api.LANGUAGE_MODEL)
 681     public <R, P> R accept(TypeVisitor<R, P> v, P p) {
 682         throw new AssertionError();
 683     }
 684 
 685     public static class JCPrimitiveType extends Type
 686             implements javax.lang.model.type.PrimitiveType {
 687 
 688         TypeTag tag;
 689 
 690         public JCPrimitiveType(TypeTag tag, TypeSymbol tsym) {
 691             this(tag, tsym, TypeMetadata.EMPTY);
 692         }
 693 
 694         private JCPrimitiveType(TypeTag tag, TypeSymbol tsym, TypeMetadata metadata) {
 695             super(tsym, metadata);
 696             this.tag = tag;
 697             Assert.check(tag.isPrimitive);
 698         }
 699 
 700         @Override
 701         public JCPrimitiveType cloneWithMetadata(TypeMetadata md) {
 702             return new JCPrimitiveType(tag, tsym, md) {
 703                 @Override
 704                 public Type baseType() { return JCPrimitiveType.this.baseType(); }
 705             };
 706         }
 707 
 708         @Override
 709         public boolean isNumeric() {
 710             return tag != BOOLEAN;
 711         }
 712 
 713         @Override
 714         public boolean isIntegral() {
 715             switch (tag) {
 716                 case CHAR:
 717                 case BYTE:
 718                 case SHORT:
 719                 case INT:
 720                 case LONG:
 721                     return true;
 722                 default:
 723                     return false;
 724             }
 725         }
 726 
 727         @Override
 728         public boolean isPrimitive() {
 729             return true;
 730         }
 731 
 732         @Override
 733         public TypeTag getTag() {
 734             return tag;
 735         }
 736 
 737         @Override
 738         public boolean isPrimitiveOrVoid() {
 739             return true;
 740         }
 741 
 742         /** Define a constant type, of the same kind as this type
 743          *  and with given constant value
 744          */
 745         @Override
 746         public Type constType(Object constValue) {
 747             final Object value = constValue;
 748             return new JCPrimitiveType(tag, tsym, metadata) {
 749                     @Override
 750                     public Object constValue() {
 751                         return value;
 752                     }
 753                     @Override
 754                     public Type baseType() {
 755                         return tsym.type;
 756                     }
 757                 };
 758         }
 759 
 760         /**
 761          * The constant value of this type, converted to String
 762          */
 763         @Override
 764         public String stringValue() {
 765             Object cv = Assert.checkNonNull(constValue());
 766             if (tag == BOOLEAN) {
 767                 return ((Integer) cv).intValue() == 0 ? "false" : "true";
 768             }
 769             else if (tag == CHAR) {
 770                 return String.valueOf((char) ((Integer) cv).intValue());
 771             }
 772             else {
 773                 return cv.toString();
 774             }
 775         }
 776 
 777         /** Is this a constant type whose value is false?
 778          */
 779         @Override
 780         public boolean isFalse() {
 781             return
 782                 tag == BOOLEAN &&
 783                 constValue() != null &&
 784                 ((Integer)constValue()).intValue() == 0;
 785         }
 786 
 787         /** Is this a constant type whose value is true?
 788          */
 789         @Override
 790         public boolean isTrue() {
 791             return
 792                 tag == BOOLEAN &&
 793                 constValue() != null &&
 794                 ((Integer)constValue()).intValue() != 0;
 795         }
 796 
 797         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 798         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
 799             return v.visitPrimitive(this, p);
 800         }
 801 
 802         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 803         public TypeKind getKind() {
 804             switch (tag) {
 805                 case BYTE:      return TypeKind.BYTE;
 806                 case CHAR:      return TypeKind.CHAR;
 807                 case SHORT:     return TypeKind.SHORT;
 808                 case INT:       return TypeKind.INT;
 809                 case LONG:      return TypeKind.LONG;
 810                 case FLOAT:     return TypeKind.FLOAT;
 811                 case DOUBLE:    return TypeKind.DOUBLE;
 812                 case BOOLEAN:   return TypeKind.BOOLEAN;
 813             }
 814             throw new AssertionError();
 815         }
 816 
 817     }
 818 
 819     public static class WildcardType extends Type
 820             implements javax.lang.model.type.WildcardType {
 821 
 822         public Type type;
 823         public BoundKind kind;
 824         public TypeVar bound;
 825 
 826         @Override
 827         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
 828             return v.visitWildcardType(this, s);
 829         }
 830 
 831         public WildcardType(Type type, BoundKind kind, TypeSymbol tsym) {
 832             this(type, kind, tsym, null, TypeMetadata.EMPTY);
 833         }
 834 
 835         public WildcardType(Type type, BoundKind kind, TypeSymbol tsym,
 836                             TypeMetadata metadata) {
 837             this(type, kind, tsym, null, metadata);
 838         }
 839 
 840         public WildcardType(Type type, BoundKind kind, TypeSymbol tsym,
 841                             TypeVar bound) {
 842             this(type, kind, tsym, bound, TypeMetadata.EMPTY);
 843         }
 844 
 845         public WildcardType(Type type, BoundKind kind, TypeSymbol tsym,
 846                             TypeVar bound, TypeMetadata metadata) {
 847             super(tsym, metadata);
 848             this.type = Assert.checkNonNull(type);
 849             this.kind = kind;
 850             this.bound = bound;
 851         }
 852 
 853         @Override
 854         public WildcardType cloneWithMetadata(TypeMetadata md) {
 855             return new WildcardType(type, kind, tsym, bound, md) {
 856                 @Override
 857                 public Type baseType() { return WildcardType.this.baseType(); }
 858             };
 859         }
 860 
 861         @Override
 862         public TypeTag getTag() {
 863             return WILDCARD;
 864         }
 865 
 866         @Override
 867         public boolean contains(Type t) {
 868             return kind != UNBOUND && type.contains(t);
 869         }
 870 
 871         public boolean isSuperBound() {
 872             return kind == SUPER ||
 873                 kind == UNBOUND;
 874         }
 875         public boolean isExtendsBound() {
 876             return kind == EXTENDS ||
 877                 kind == UNBOUND;
 878         }
 879         public boolean isUnbound() {
 880             // is it `?` or `? extends Object`?
 881             return kind == UNBOUND ||
 882                     (kind == EXTENDS && type.tsym.flatName() == type.tsym.name.table.names.java_lang_Object);
 883         }
 884 
 885         @Override
 886         public boolean isReference() {
 887             return true;
 888         }
 889 
 890         @Override
 891         public boolean isNullOrReference() {
 892             return true;
 893         }
 894 
 895         @Override
 896         public Type withTypeVar(Type t) {
 897             //-System.err.println(this+".withTypeVar("+t+");");//DEBUG
 898             if (bound == t)
 899                 return this;
 900             bound = (TypeVar)t;
 901             return this;
 902         }
 903 
 904         boolean isPrintingBound = false;
 905         @DefinedBy(Api.LANGUAGE_MODEL)
 906         public String toString() {
 907             StringBuilder s = new StringBuilder();
 908             appendAnnotationsString(s);
 909             s.append(kind.toString());
 910             if (kind != UNBOUND)
 911                 s.append(type);
 912             if (moreInfo && bound != null && !isPrintingBound)
 913                 try {
 914                     isPrintingBound = true;
 915                     s.append("{:").append(bound.getUpperBound()).append(":}");
 916                 } finally {
 917                     isPrintingBound = false;
 918                 }
 919             return s.toString();
 920         }
 921 
 922         @DefinedBy(Api.LANGUAGE_MODEL)
 923         public Type getExtendsBound() {
 924             if (kind == EXTENDS)
 925                 return type;
 926             else
 927                 return null;
 928         }
 929 
 930         @DefinedBy(Api.LANGUAGE_MODEL)
 931         public Type getSuperBound() {
 932             if (kind == SUPER)
 933                 return type;
 934             else
 935                 return null;
 936         }
 937 
 938         @DefinedBy(Api.LANGUAGE_MODEL)
 939         public TypeKind getKind() {
 940             return TypeKind.WILDCARD;
 941         }
 942 
 943         @DefinedBy(Api.LANGUAGE_MODEL)
 944         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
 945             return v.visitWildcard(this, p);
 946         }
 947     }
 948 
 949     public static class ClassType extends Type implements DeclaredType, LoadableConstant,
 950                                                           javax.lang.model.type.ErrorType {
 951 
 952         /** The enclosing type of this type. If this is the type of an inner
 953          *  class, outer_field refers to the type of its enclosing
 954          *  instance class, in all other cases it refers to noType.
 955          */
 956         private Type outer_field;
 957 
 958         /** The type parameters of this type (to be set once class is loaded).
 959          */
 960         public List<Type> typarams_field;
 961 
 962         /** A cache variable for the type parameters of this type,
 963          *  appended to all parameters of its enclosing class.
 964          *  @see #allparams
 965          */
 966         public List<Type> allparams_field;
 967 
 968         /** The supertype of this class (to be set once class is loaded).
 969          */
 970         public Type supertype_field;
 971 
 972         /** The interfaces of this class (to be set once class is loaded).
 973          */
 974         public List<Type> interfaces_field;
 975 
 976         /** All the interfaces of this class, including missing ones.
 977          */
 978         public List<Type> all_interfaces_field;
 979 
 980         public ClassType(Type outer, List<Type> typarams, TypeSymbol tsym) {
 981             this(outer, typarams, tsym, TypeMetadata.EMPTY);
 982         }
 983 
 984         public ClassType(Type outer, List<Type> typarams, TypeSymbol tsym,
 985                          TypeMetadata metadata) {
 986             super(tsym, metadata);
 987             this.outer_field = outer;
 988             this.typarams_field = typarams;
 989             this.allparams_field = null;
 990             this.supertype_field = null;
 991             this.interfaces_field = null;
 992         }
 993 
 994         public int poolTag() {
 995             return ClassFile.CONSTANT_Class;
 996         }
 997 
 998         @Override
 999         public ClassType cloneWithMetadata(TypeMetadata md) {
1000             return new ClassType(outer_field, typarams_field, tsym, md) {
1001                 @Override
1002                 public Type baseType() { return ClassType.this.baseType(); }
1003             };
1004         }
1005 
1006         @Override
1007         public TypeTag getTag() {
1008             return CLASS;
1009         }
1010 
1011         @Override
1012         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1013             return v.visitClassType(this, s);
1014         }
1015 
1016         public Type constType(Object constValue) {
1017             final Object value = constValue;
1018             return new ClassType(getEnclosingType(), typarams_field, tsym, metadata) {
1019                     @Override
1020                     public Object constValue() {
1021                         return value;
1022                     }
1023                     @Override
1024                     public Type baseType() {
1025                         return tsym.type;
1026                     }
1027                 };
1028         }
1029 
1030         /** The Java source which this type represents.
1031          */
1032         @DefinedBy(Api.LANGUAGE_MODEL)
1033         public String toString() {
1034             StringBuilder buf = new StringBuilder();
1035             if (getEnclosingType().hasTag(CLASS) && tsym.owner.kind == TYP) {
1036                 buf.append(getEnclosingType().toString());
1037                 buf.append(".");
1038                 appendAnnotationsString(buf);
1039                 buf.append(className(tsym, false));
1040             } else {
1041                 if (isAnnotated()) {
1042                     if (!tsym.packge().isUnnamed()) {
1043                         buf.append(tsym.packge());
1044                         buf.append(".");
1045                     }
1046                     ListBuffer<Name> names = new ListBuffer<>();
1047                     for (Symbol sym = tsym.owner; sym != null && sym.kind == TYP; sym = sym.owner) {
1048                         names.prepend(sym.name);
1049                     }
1050                     for (Name name : names) {
1051                         buf.append(name);
1052                         buf.append(".");
1053                     }
1054                     appendAnnotationsString(buf);
1055                     buf.append(tsym.name);
1056                 } else {
1057                     buf.append(className(tsym, true));
1058                 }
1059             }
1060 
1061             if (getTypeArguments().nonEmpty()) {
1062                 buf.append('<');
1063                 buf.append(getTypeArguments().toString());
1064                 buf.append(">");
1065             }
1066             return buf.toString();
1067         }
1068 //where
1069             private String className(Symbol sym, boolean longform) {
1070                 if (sym.name.isEmpty() && (sym.flags() & COMPOUND) != 0) {
1071                     StringBuilder s = new StringBuilder(supertype_field.toString());
1072                     for (List<Type> is=interfaces_field; is.nonEmpty(); is = is.tail) {
1073                         s.append("&");
1074                         s.append(is.head.toString());
1075                     }
1076                     return s.toString();
1077                 } else if (sym.name.isEmpty()) {
1078                     String s;
1079                     ClassType norm = (ClassType) tsym.type;
1080                     if (norm == null) {
1081                         s = Log.getLocalizedString("anonymous.class", (Object)null);
1082                     } else if (norm.interfaces_field != null && norm.interfaces_field.nonEmpty()) {
1083                         s = Log.getLocalizedString("anonymous.class",
1084                                                    norm.interfaces_field.head);
1085                     } else {
1086                         s = Log.getLocalizedString("anonymous.class",
1087                                                    norm.supertype_field);
1088                     }
1089                     if (moreInfo)
1090                         s += String.valueOf(sym.hashCode());
1091                     return s;
1092                 } else if (longform) {
1093                     return sym.getQualifiedName().toString();
1094                 } else {
1095                     return sym.name.toString();
1096                 }
1097             }
1098 
1099         @DefinedBy(Api.LANGUAGE_MODEL)
1100         public List<Type> getTypeArguments() {
1101             if (typarams_field == null) {
1102                 complete();
1103                 if (typarams_field == null)
1104                     typarams_field = List.nil();
1105             }
1106             return typarams_field;
1107         }
1108 
1109         public boolean hasErasedSupertypes() {
1110             return isRaw();
1111         }
1112 
1113         @DefinedBy(Api.LANGUAGE_MODEL)
1114         public Type getEnclosingType() {
1115             return outer_field;
1116         }
1117 
1118         public void setEnclosingType(Type outer) {
1119             outer_field = outer;
1120         }
1121 
1122         public List<Type> allparams() {
1123             if (allparams_field == null) {
1124                 allparams_field = getTypeArguments().prependList(getEnclosingType().allparams());
1125             }
1126             return allparams_field;
1127         }
1128 
1129         public boolean isErroneous() {
1130             return
1131                 getEnclosingType().isErroneous() ||
1132                 isErroneous(getTypeArguments()) ||
1133                 this != tsym.type && tsym.type.isErroneous();
1134         }
1135 
1136         public boolean isParameterized() {
1137             return allparams().tail != null;
1138             // optimization, was: allparams().nonEmpty();
1139         }
1140 
1141         @Override
1142         public boolean isReference() {
1143             return true;
1144         }
1145 
1146         @Override
1147         public boolean isNullOrReference() {
1148             return true;
1149         }
1150 
1151         /** A cache for the rank. */
1152         int rank_field = -1;
1153 
1154         /** A class type is raw if it misses some
1155          *  of its type parameter sections.
1156          *  After validation, this is equivalent to:
1157          *  {@code allparams.isEmpty() && tsym.type.allparams.nonEmpty(); }
1158          */
1159         public boolean isRaw() {
1160             return
1161                 this != tsym.type && // necessary, but not sufficient condition
1162                 tsym.type.allparams().nonEmpty() &&
1163                 allparams().isEmpty();
1164         }
1165 
1166         public boolean contains(Type elem) {
1167             return
1168                 elem.equalsIgnoreMetadata(this)
1169                 || (isParameterized()
1170                     && (getEnclosingType().contains(elem) || contains(getTypeArguments(), elem)))
1171                 || (isCompound()
1172                     && (supertype_field.contains(elem) || contains(interfaces_field, elem)));
1173         }
1174 
1175         public void complete() {
1176             tsym.complete();
1177         }
1178 
1179         @DefinedBy(Api.LANGUAGE_MODEL)
1180         public TypeKind getKind() {
1181             tsym.apiComplete();
1182             return tsym.kind == TYP ? TypeKind.DECLARED : TypeKind.ERROR;
1183         }
1184 
1185         @DefinedBy(Api.LANGUAGE_MODEL)
1186         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1187             return v.visitDeclared(this, p);
1188         }
1189     }
1190 
1191     public static class ErasedClassType extends ClassType {
1192         public ErasedClassType(Type outer, TypeSymbol tsym,
1193                                TypeMetadata metadata) {
1194             super(outer, List.nil(), tsym, metadata);
1195         }
1196 
1197         @Override
1198         public boolean hasErasedSupertypes() {
1199             return true;
1200         }
1201     }
1202 
1203     // a clone of a ClassType that knows about the alternatives of a union type.
1204     public static class UnionClassType extends ClassType implements UnionType {
1205         final List<? extends Type> alternatives_field;
1206 
1207         public UnionClassType(ClassType ct, List<? extends Type> alternatives) {
1208             // Presently no way to refer to this type directly, so we
1209             // cannot put annotations directly on it.
1210             super(ct.outer_field, ct.typarams_field, ct.tsym);
1211             allparams_field = ct.allparams_field;
1212             supertype_field = ct.supertype_field;
1213             interfaces_field = ct.interfaces_field;
1214             all_interfaces_field = ct.interfaces_field;
1215             alternatives_field = alternatives;
1216         }
1217 
1218         @Override
1219         public UnionClassType cloneWithMetadata(TypeMetadata md) {
1220             throw new AssertionError("Cannot add metadata to a union type");
1221         }
1222 
1223         public Type getLub() {
1224             return tsym.type;
1225         }
1226 
1227         @DefinedBy(Api.LANGUAGE_MODEL)
1228         public java.util.List<? extends TypeMirror> getAlternatives() {
1229             return Collections.unmodifiableList(alternatives_field);
1230         }
1231 
1232         @Override
1233         public boolean isUnion() {
1234             return true;
1235         }
1236 
1237         @Override
1238         public boolean isCompound() {
1239             return getLub().isCompound();
1240         }
1241 
1242         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1243         public TypeKind getKind() {
1244             return TypeKind.UNION;
1245         }
1246 
1247         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1248         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1249             return v.visitUnion(this, p);
1250         }
1251 
1252         public Iterable<? extends Type> getAlternativeTypes() {
1253             return alternatives_field;
1254         }
1255     }
1256 
1257     // a clone of a ClassType that knows about the bounds of an intersection type.
1258     public static class IntersectionClassType extends ClassType implements IntersectionType {
1259 
1260         public boolean allInterfaces;
1261 
1262         public IntersectionClassType(List<Type> bounds, ClassSymbol csym, boolean allInterfaces) {
1263             // Presently no way to refer to this type directly, so we
1264             // cannot put annotations directly on it.
1265             super(Type.noType, List.nil(), csym);
1266             this.allInterfaces = allInterfaces;
1267             Assert.check((csym.flags() & COMPOUND) != 0);
1268             supertype_field = bounds.head;
1269             interfaces_field = bounds.tail;
1270             Assert.check(!supertype_field.tsym.isCompleted() ||
1271                     !supertype_field.isInterface(), supertype_field);
1272         }
1273 
1274         @Override
1275         public IntersectionClassType cloneWithMetadata(TypeMetadata md) {
1276             throw new AssertionError("Cannot add metadata to an intersection type");
1277         }
1278 
1279         @DefinedBy(Api.LANGUAGE_MODEL)
1280         public java.util.List<? extends TypeMirror> getBounds() {
1281             return Collections.unmodifiableList(getExplicitComponents());
1282         }
1283 
1284         @Override
1285         public boolean isCompound() {
1286             return true;
1287         }
1288 
1289         public List<Type> getComponents() {
1290             return interfaces_field.prepend(supertype_field);
1291         }
1292 
1293         @Override
1294         public boolean isIntersection() {
1295             return true;
1296         }
1297 
1298         public List<Type> getExplicitComponents() {
1299             return allInterfaces ?
1300                     interfaces_field :
1301                     getComponents();
1302         }
1303 
1304         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1305         public TypeKind getKind() {
1306             return TypeKind.INTERSECTION;
1307         }
1308 
1309         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1310         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1311             return v.visitIntersection(this, p);
1312         }
1313     }
1314 
1315     public static class ArrayType extends Type
1316             implements LoadableConstant, javax.lang.model.type.ArrayType {
1317 
1318         public Type elemtype;
1319 
1320         public ArrayType(Type elemtype, TypeSymbol arrayClass) {
1321             this(elemtype, arrayClass, TypeMetadata.EMPTY);
1322         }
1323 
1324         public ArrayType(Type elemtype, TypeSymbol arrayClass,
1325                          TypeMetadata metadata) {
1326             super(arrayClass, metadata);
1327             this.elemtype = elemtype;
1328         }
1329 
1330         public ArrayType(ArrayType that) {
1331             //note: type metadata is deliberately shared here, as we want side-effects from annotation
1332             //processing to flow from original array to the cloned array.
1333             this(that.elemtype, that.tsym, that.getMetadata());
1334         }
1335 
1336         public int poolTag() {
1337             return ClassFile.CONSTANT_Class;
1338         }
1339 
1340         @Override
1341         public ArrayType cloneWithMetadata(TypeMetadata md) {
1342             return new ArrayType(elemtype, tsym, md) {
1343                 @Override
1344                 public Type baseType() { return ArrayType.this.baseType(); }
1345             };
1346         }
1347 
1348         @Override
1349         public TypeTag getTag() {
1350             return ARRAY;
1351         }
1352 
1353         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1354             return v.visitArrayType(this, s);
1355         }
1356 
1357         @DefinedBy(Api.LANGUAGE_MODEL)
1358         public String toString() {
1359             StringBuilder sb = new StringBuilder();
1360 
1361             // First append root component type
1362             Type t = elemtype;
1363             while (t.getKind() == TypeKind.ARRAY)
1364                 t = ((ArrayType) t).getComponentType();
1365             sb.append(t);
1366 
1367             // then append @Anno[] @Anno[] ... @Anno[]
1368             t = this;
1369             do {
1370                 t.appendAnnotationsString(sb, true);
1371                 sb.append("[]");
1372                 t = ((ArrayType) t).getComponentType();
1373             } while (t.getKind() == TypeKind.ARRAY);
1374 
1375             return sb.toString();
1376         }
1377 
1378         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1379         public boolean equals(Object obj) {
1380             return (obj instanceof ArrayType arrayType)
1381                     && (this == arrayType || elemtype.equals(arrayType.elemtype));
1382         }
1383 
1384         @DefinedBy(Api.LANGUAGE_MODEL)
1385         public int hashCode() {
1386             return (ARRAY.ordinal() << 5) + elemtype.hashCode();
1387         }
1388 
1389         public boolean isVarargs() {
1390             return false;
1391         }
1392 
1393         public List<Type> allparams() { return elemtype.allparams(); }
1394 
1395         public boolean isErroneous() {
1396             return elemtype.isErroneous();
1397         }
1398 
1399         public boolean isParameterized() {
1400             return elemtype.isParameterized();
1401         }
1402 
1403         @Override
1404         public boolean isReference() {
1405             return true;
1406         }
1407 
1408         @Override
1409         public boolean isNullOrReference() {
1410             return true;
1411         }
1412 
1413         public boolean isRaw() {
1414             return elemtype.isRaw();
1415         }
1416 
1417         public ArrayType makeVarargs() {
1418             return new ArrayType(elemtype, tsym, metadata) {
1419                 @Override
1420                 public boolean isVarargs() {
1421                     return true;
1422                 }
1423             };
1424         }
1425 
1426         public boolean contains(Type elem) {
1427             return elem.equalsIgnoreMetadata(this) || elemtype.contains(elem);
1428         }
1429 
1430         public void complete() {
1431             elemtype.complete();
1432         }
1433 
1434         @DefinedBy(Api.LANGUAGE_MODEL)
1435         public Type getComponentType() {
1436             return elemtype;
1437         }
1438 
1439         @DefinedBy(Api.LANGUAGE_MODEL)
1440         public TypeKind getKind() {
1441             return TypeKind.ARRAY;
1442         }
1443 
1444         @DefinedBy(Api.LANGUAGE_MODEL)
1445         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1446             return v.visitArray(this, p);
1447         }
1448     }
1449 
1450     public static class MethodType extends Type implements ExecutableType, LoadableConstant {
1451 
1452         public List<Type> argtypes;
1453         public Type restype;
1454         public List<Type> thrown;
1455 
1456         /** The type annotations on the method receiver.
1457          */
1458         public Type recvtype;
1459 
1460         public MethodType(List<Type> argtypes,
1461                           Type restype,
1462                           List<Type> thrown,
1463                           TypeSymbol methodClass) {
1464             // Presently no way to refer to a method type directly, so
1465             // we cannot put type annotations on it.
1466             super(methodClass, TypeMetadata.EMPTY);
1467             this.argtypes = argtypes;
1468             this.restype = restype;
1469             this.thrown = thrown;
1470         }
1471 
1472         @Override
1473         public MethodType cloneWithMetadata(TypeMetadata md) {
1474             throw new AssertionError("Cannot add metadata to a method type");
1475         }
1476 
1477         @Override
1478         public TypeTag getTag() {
1479             return METHOD;
1480         }
1481 
1482         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1483             return v.visitMethodType(this, s);
1484         }
1485 
1486         /** The Java source which this type represents.
1487          *
1488          *  XXX 06/09/99 iris This isn't correct Java syntax, but it probably
1489          *  should be.
1490          */
1491         @DefinedBy(Api.LANGUAGE_MODEL)
1492         public String toString() {
1493             StringBuilder sb = new StringBuilder();
1494             appendAnnotationsString(sb);
1495             sb.append('(');
1496             sb.append(argtypes);
1497             sb.append(')');
1498             sb.append(restype);
1499             return sb.toString();
1500         }
1501 
1502         @DefinedBy(Api.LANGUAGE_MODEL)
1503         public List<Type>        getParameterTypes() { return argtypes; }
1504         @DefinedBy(Api.LANGUAGE_MODEL)
1505         public Type              getReturnType()     { return restype; }
1506         @DefinedBy(Api.LANGUAGE_MODEL)
1507         public Type              getReceiverType()   {
1508             return (recvtype == null) ? Type.noType : recvtype;
1509         }
1510         @DefinedBy(Api.LANGUAGE_MODEL)
1511         public List<Type>        getThrownTypes()    { return thrown; }
1512 
1513         public boolean isErroneous() {
1514             return
1515                 isErroneous(argtypes) ||
1516                 restype != null && restype.isErroneous();
1517         }
1518 
1519         @Override
1520         public int poolTag() {
1521             return ClassFile.CONSTANT_MethodType;
1522         }
1523 
1524         public boolean contains(Type elem) {
1525             return elem.equalsIgnoreMetadata(this) || contains(argtypes, elem) || restype.contains(elem) || contains(thrown, elem);
1526         }
1527 
1528         public MethodType asMethodType() { return this; }
1529 
1530         public void complete() {
1531             for (List<Type> l = argtypes; l.nonEmpty(); l = l.tail)
1532                 l.head.complete();
1533             restype.complete();
1534             recvtype.complete();
1535             for (List<Type> l = thrown; l.nonEmpty(); l = l.tail)
1536                 l.head.complete();
1537         }
1538 
1539         @DefinedBy(Api.LANGUAGE_MODEL)
1540         public List<TypeVar> getTypeVariables() {
1541             return List.nil();
1542         }
1543 
1544         public TypeSymbol asElement() {
1545             return null;
1546         }
1547 
1548         @DefinedBy(Api.LANGUAGE_MODEL)
1549         public TypeKind getKind() {
1550             return TypeKind.EXECUTABLE;
1551         }
1552 
1553         @DefinedBy(Api.LANGUAGE_MODEL)
1554         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1555             return v.visitExecutable(this, p);
1556         }
1557     }
1558 
1559     public static class PackageType extends Type implements NoType {
1560 
1561         PackageType(PackageSymbol tsym) {
1562             // Package types cannot be annotated
1563             super(tsym, TypeMetadata.EMPTY);
1564         }
1565 
1566         @Override
1567         public PackageType cloneWithMetadata(TypeMetadata md) {
1568             throw new AssertionError("Cannot add metadata to a package type");
1569         }
1570 
1571         @Override
1572         public TypeTag getTag() {
1573             return PACKAGE;
1574         }
1575 
1576         @Override
1577         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1578             return v.visitPackageType(this, s);
1579         }
1580 
1581         @DefinedBy(Api.LANGUAGE_MODEL)
1582         public String toString() {
1583             return tsym.getQualifiedName().toString();
1584         }
1585 
1586         @DefinedBy(Api.LANGUAGE_MODEL)
1587         public TypeKind getKind() {
1588             return TypeKind.PACKAGE;
1589         }
1590 
1591         @DefinedBy(Api.LANGUAGE_MODEL)
1592         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1593             return v.visitNoType(this, p);
1594         }
1595     }
1596 
1597     public static class ModuleType extends Type implements NoType {
1598 
1599         ModuleType(ModuleSymbol tsym) {
1600             // Module types cannot be annotated
1601             super(tsym, TypeMetadata.EMPTY);
1602         }
1603 
1604         @Override
1605         public ModuleType cloneWithMetadata(TypeMetadata md) {
1606             throw new AssertionError("Cannot add metadata to a module type");
1607         }
1608 
1609         @Override
1610         public ModuleType annotatedType(List<Attribute.TypeCompound> annos) {
1611             throw new AssertionError("Cannot annotate a module type");
1612         }
1613 
1614         @Override
1615         public TypeTag getTag() {
1616             return TypeTag.MODULE;
1617         }
1618 
1619         @Override
1620         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1621             return v.visitModuleType(this, s);
1622         }
1623 
1624         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1625         public String toString() {
1626             return tsym.getQualifiedName().toString();
1627         }
1628 
1629         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1630         public TypeKind getKind() {
1631             return TypeKind.MODULE;
1632         }
1633 
1634         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1635         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1636             return v.visitNoType(this, p);
1637         }
1638     }
1639 
1640     public static class TypeVar extends Type implements TypeVariable {
1641 
1642         /** The upper bound of this type variable; set from outside.
1643          *  Must be nonempty once it is set.
1644          *  For a bound, `bound' is the bound type itself.
1645          *  Multiple bounds are expressed as a single class type which has the
1646          *  individual bounds as superclass, respectively interfaces.
1647          *  The class type then has as `tsym' a compiler generated class `c',
1648          *  which has a flag COMPOUND and whose owner is the type variable
1649          *  itself. Furthermore, the erasure_field of the class
1650          *  points to the first class or interface bound.
1651          */
1652         private Type _bound = null;
1653 
1654         /** The lower bound of this type variable.
1655          *  TypeVars don't normally have a lower bound, so it is normally set
1656          *  to syms.botType.
1657          *  Subtypes, such as CapturedType, may provide a different value.
1658          */
1659         public Type lower;
1660 
1661         public TypeVar(Name name, Symbol owner, Type lower) {
1662             super(null, TypeMetadata.EMPTY);
1663             Assert.checkNonNull(lower);
1664             tsym = new TypeVariableSymbol(0, name, this, owner);
1665             this.setUpperBound(null);
1666             this.lower = lower;
1667         }
1668 
1669         public TypeVar(TypeSymbol tsym, Type bound, Type lower) {
1670             this(tsym, bound, lower, TypeMetadata.EMPTY);
1671         }
1672 
1673         public TypeVar(TypeSymbol tsym, Type bound, Type lower,
1674                        TypeMetadata metadata) {
1675             super(tsym, metadata);
1676             Assert.checkNonNull(lower);
1677             this.setUpperBound(bound);
1678             this.lower = lower;
1679         }
1680 
1681         @Override
1682         public TypeVar cloneWithMetadata(TypeMetadata md) {
1683             return new TypeVar(tsym, getUpperBound(), lower, md) {
1684                 @Override
1685                 public Type baseType() { return TypeVar.this.baseType(); }
1686 
1687                 @Override @DefinedBy(Api.LANGUAGE_MODEL)
1688                 public Type getUpperBound() { return TypeVar.this.getUpperBound(); }
1689 
1690                 public void setUpperBound(Type bound) { TypeVar.this.setUpperBound(bound); }
1691             };
1692         }
1693 
1694         @Override
1695         public TypeTag getTag() {
1696             return TYPEVAR;
1697         }
1698 
1699         @Override
1700         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1701             return v.visitTypeVar(this, s);
1702         }
1703 
1704         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1705         public Type getUpperBound() { return _bound; }
1706 
1707         public void setUpperBound(Type bound) { this._bound = bound; }
1708 
1709         int rank_field = -1;
1710 
1711         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1712         public Type getLowerBound() {
1713             return lower;
1714         }
1715 
1716         @DefinedBy(Api.LANGUAGE_MODEL)
1717         public TypeKind getKind() {
1718             return TypeKind.TYPEVAR;
1719         }
1720 
1721         public boolean isCaptured() {
1722             return false;
1723         }
1724 
1725         @Override
1726         public boolean isReference() {
1727             return true;
1728         }
1729 
1730         @Override
1731         public boolean isNullOrReference() {
1732             return true;
1733         }
1734 
1735         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1736         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1737             return v.visitTypeVariable(this, p);
1738         }
1739     }
1740 
1741     /** A captured type variable comes from wildcards which can have
1742      *  both upper and lower bound.  CapturedType extends TypeVar with
1743      *  a lower bound.
1744      */
1745     public static class CapturedType extends TypeVar {
1746 
1747         public WildcardType wildcard;
1748 
1749         public CapturedType(Name name,
1750                             Symbol owner,
1751                             Type upper,
1752                             Type lower,
1753                             WildcardType wildcard) {
1754             super(name, owner, lower);
1755             this.lower = Assert.checkNonNull(lower);
1756             this.setUpperBound(upper);
1757             this.wildcard = wildcard;
1758         }
1759 
1760         public CapturedType(TypeSymbol tsym,
1761                             Type bound,
1762                             Type upper,
1763                             Type lower,
1764                             WildcardType wildcard,
1765                             TypeMetadata metadata) {
1766             super(tsym, bound, lower, metadata);
1767             this.wildcard = wildcard;
1768         }
1769 
1770         @Override
1771         public CapturedType cloneWithMetadata(TypeMetadata md) {
1772             return new CapturedType(tsym, getUpperBound(), getUpperBound(), lower, wildcard, md) {
1773                 @Override
1774                 public Type baseType() { return CapturedType.this.baseType(); }
1775 
1776                 @Override @DefinedBy(Api.LANGUAGE_MODEL)
1777                 public Type getUpperBound() { return CapturedType.this.getUpperBound(); }
1778 
1779                 public void setUpperBound(Type bound) { CapturedType.this.setUpperBound(bound); }
1780             };
1781         }
1782 
1783         @Override
1784         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1785             return v.visitCapturedType(this, s);
1786         }
1787 
1788         @Override
1789         public boolean isCaptured() {
1790             return true;
1791         }
1792 
1793         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1794         public String toString() {
1795             StringBuilder sb = new StringBuilder();
1796             appendAnnotationsString(sb);
1797             sb.append("capture#");
1798             sb.append((hashCode() & 0xFFFFFFFFL) % Printer.PRIME);
1799             sb.append(" of ");
1800             sb.append(wildcard);
1801             return sb.toString();
1802         }
1803     }
1804 
1805     public abstract static class DelegatedType extends Type {
1806         public Type qtype;
1807         public TypeTag tag;
1808 
1809         public DelegatedType(TypeTag tag, Type qtype) {
1810             this(tag, qtype, TypeMetadata.EMPTY);
1811         }
1812 
1813         public DelegatedType(TypeTag tag, Type qtype,
1814                              TypeMetadata metadata) {
1815             super(qtype.tsym, metadata);
1816             this.tag = tag;
1817             this.qtype = qtype;
1818         }
1819 
1820         public TypeTag getTag() { return tag; }
1821         @DefinedBy(Api.LANGUAGE_MODEL)
1822         public String toString() { return qtype.toString(); }
1823         public List<Type> getTypeArguments() { return qtype.getTypeArguments(); }
1824         public Type getEnclosingType() { return qtype.getEnclosingType(); }
1825         public List<Type> getParameterTypes() { return qtype.getParameterTypes(); }
1826         public Type getReturnType() { return qtype.getReturnType(); }
1827         public Type getReceiverType() { return qtype.getReceiverType(); }
1828         public List<Type> getThrownTypes() { return qtype.getThrownTypes(); }
1829         public List<Type> allparams() { return qtype.allparams(); }
1830         public Type getUpperBound() { return qtype.getUpperBound(); }
1831         public boolean isErroneous() { return qtype.isErroneous(); }
1832     }
1833 
1834     /**
1835      * The type of a generic method type. It consists of a method type and
1836      * a list of method type-parameters that are used within the method
1837      * type.
1838      */
1839     public static class ForAll extends DelegatedType implements ExecutableType {
1840         public List<Type> tvars;
1841 
1842         public ForAll(List<Type> tvars, Type qtype) {
1843             super(FORALL, (MethodType)qtype);
1844             this.tvars = tvars;
1845         }
1846 
1847         @Override
1848         public ForAll cloneWithMetadata(TypeMetadata md) {
1849             throw new AssertionError("Cannot add metadata to a forall type");
1850         }
1851 
1852         @Override
1853         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1854             return v.visitForAll(this, s);
1855         }
1856 
1857         @DefinedBy(Api.LANGUAGE_MODEL)
1858         public String toString() {
1859             StringBuilder sb = new StringBuilder();
1860             appendAnnotationsString(sb);
1861             sb.append('<');
1862             sb.append(tvars);
1863             sb.append('>');
1864             sb.append(qtype);
1865             return sb.toString();
1866         }
1867 
1868         public List<Type> getTypeArguments()   { return tvars; }
1869 
1870         public boolean isErroneous()  {
1871             return qtype.isErroneous();
1872         }
1873 
1874         public boolean contains(Type elem) {
1875             return qtype.contains(elem);
1876         }
1877 
1878         public MethodType asMethodType() {
1879             return (MethodType)qtype;
1880         }
1881 
1882         public void complete() {
1883             for (List<Type> l = tvars; l.nonEmpty(); l = l.tail) {
1884                 ((TypeVar)l.head).getUpperBound().complete();
1885             }
1886             qtype.complete();
1887         }
1888 
1889         @DefinedBy(Api.LANGUAGE_MODEL)
1890         public List<TypeVar> getTypeVariables() {
1891             return List.convert(TypeVar.class, getTypeArguments());
1892         }
1893 
1894         @DefinedBy(Api.LANGUAGE_MODEL)
1895         public TypeKind getKind() {
1896             return TypeKind.EXECUTABLE;
1897         }
1898 
1899         @DefinedBy(Api.LANGUAGE_MODEL)
1900         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
1901             return v.visitExecutable(this, p);
1902         }
1903     }
1904 
1905     /** A class for inference variables, for use during method/diamond type
1906      *  inference. An inference variable has upper/lower bounds and a set
1907      *  of equality constraints. Such bounds are set during subtyping, type-containment,
1908      *  type-equality checks, when the types being tested contain inference variables.
1909      *  A change listener can be attached to an inference variable, to receive notifications
1910      *  whenever the bounds of an inference variable change.
1911      */
1912     public static class UndetVar extends DelegatedType {
1913 
1914         enum Kind {
1915             NORMAL,
1916             CAPTURED,
1917             THROWS;
1918         }
1919 
1920         /** Inference variable change listener. The listener method is called
1921          *  whenever a change to the inference variable's bounds occurs
1922          */
1923         public interface UndetVarListener {
1924             /** called when some inference variable bounds (of given kinds ibs) change */
1925             void varBoundChanged(UndetVar uv, InferenceBound ib, Type bound, boolean update);
1926             /** called when the inferred type is set on some inference variable */
1927             default void varInstantiated(UndetVar uv) { Assert.error(); }
1928         }
1929 
1930         /**
1931          * Inference variable bound kinds
1932          */
1933         public enum InferenceBound {
1934             /** lower bounds */
1935             LOWER {
1936                 public InferenceBound complement() { return UPPER; }
1937             },
1938             /** equality constraints */
1939             EQ {
1940                 public InferenceBound complement() { return EQ; }
1941             },
1942             /** upper bounds */
1943             UPPER {
1944                 public InferenceBound complement() { return LOWER; }
1945             };
1946 
1947             public abstract InferenceBound complement();
1948 
1949             public boolean lessThan(InferenceBound that) {
1950                 if (that == this) {
1951                     return false;
1952                 } else {
1953                     switch (that) {
1954                         case UPPER: return true;
1955                         case LOWER: return false;
1956                         case EQ: return (this != UPPER);
1957                         default:
1958                             Assert.error("Cannot get here!");
1959                             return false;
1960                     }
1961                 }
1962             }
1963         }
1964 
1965         /** list of incorporation actions (used by the incorporation engine). */
1966         public ArrayDeque<IncorporationAction> incorporationActions = new ArrayDeque<>();
1967 
1968         /** inference variable bounds */
1969         protected Map<InferenceBound, List<Type>> bounds;
1970 
1971         /** inference variable's inferred type (set from Infer.java) */
1972         private Type inst = null;
1973 
1974         /** number of declared (upper) bounds */
1975         public int declaredCount;
1976 
1977         /** inference variable's change listener */
1978         public UndetVarListener listener = null;
1979 
1980         Kind kind;
1981 
1982         @Override
1983         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
1984             return v.visitUndetVar(this, s);
1985         }
1986 
1987         public UndetVar(TypeVar origin, UndetVarListener listener, Types types) {
1988             // This is a synthesized internal type, so we cannot annotate it.
1989             super(UNDETVAR, origin);
1990             this.kind = origin.isCaptured() ?
1991                     Kind.CAPTURED :
1992                     Kind.NORMAL;
1993             this.listener = listener;
1994             bounds = new EnumMap<>(InferenceBound.class);
1995             List<Type> declaredBounds = types.getBounds(origin);
1996             declaredCount = declaredBounds.length();
1997             bounds.put(InferenceBound.UPPER, List.nil());
1998             bounds.put(InferenceBound.LOWER, List.nil());
1999             bounds.put(InferenceBound.EQ, List.nil());
2000             for (Type t : declaredBounds.reverse()) {
2001                 //add bound works in reverse order
2002                 addBound(InferenceBound.UPPER, t, types, true);
2003             }
2004             if (origin.isCaptured() && !origin.lower.hasTag(BOT)) {
2005                 //add lower bound if needed
2006                 addBound(InferenceBound.LOWER, origin.lower, types, true);
2007             }
2008         }
2009 
2010         @DefinedBy(Api.LANGUAGE_MODEL)
2011         public String toString() {
2012             StringBuilder sb = new StringBuilder();
2013             appendAnnotationsString(sb);
2014             if (inst == null) {
2015                 sb.append(qtype);
2016                 sb.append('?');
2017             } else {
2018                 sb.append(inst);
2019             }
2020             return sb.toString();
2021         }
2022 
2023         public String debugString() {
2024             String result = "inference var = " + qtype + "\n";
2025             if (inst != null) {
2026                 result += "inst = " + inst + '\n';
2027             }
2028             for (InferenceBound bound: InferenceBound.values()) {
2029                 List<Type> aboundList = bounds.get(bound);
2030                 if (aboundList != null && aboundList.size() > 0) {
2031                     result += bound + " = " + aboundList + '\n';
2032                 }
2033             }
2034             return result;
2035         }
2036 
2037         public void setThrow() {
2038             if (this.kind == Kind.CAPTURED) {
2039                 //invalid state transition
2040                 throw new IllegalStateException();
2041             }
2042             this.kind = Kind.THROWS;
2043         }
2044 
2045         /**
2046          * Returns a new copy of this undet var.
2047          */
2048         public UndetVar dup(Types types) {
2049             UndetVar uv2 = new UndetVar((TypeVar)qtype, listener, types);
2050             dupTo(uv2, types);
2051             return uv2;
2052         }
2053 
2054         /**
2055          * Dumps the contents of this undet var on another undet var.
2056          */
2057         public void dupTo(UndetVar uv2, Types types) {
2058             uv2.listener = null;
2059             uv2.bounds.clear();
2060             for (InferenceBound ib : InferenceBound.values()) {
2061                 uv2.bounds.put(ib, List.nil());
2062                 for (Type t : getBounds(ib)) {
2063                     uv2.addBound(ib, t, types, true);
2064                 }
2065             }
2066             uv2.inst = inst;
2067             uv2.listener = listener;
2068             uv2.incorporationActions = new ArrayDeque<>();
2069             for (IncorporationAction action : incorporationActions) {
2070                 uv2.incorporationActions.add(action.dup(uv2));
2071             }
2072             uv2.kind = kind;
2073         }
2074 
2075         @Override
2076         public UndetVar cloneWithMetadata(TypeMetadata md) {
2077             throw new AssertionError("Cannot add metadata to an UndetVar type");
2078         }
2079 
2080         @Override
2081         public boolean isPartial() {
2082             return true;
2083         }
2084 
2085         @Override
2086         public Type baseType() {
2087             return (inst == null) ? this : inst.baseType();
2088         }
2089 
2090         public Type getInst() {
2091             return inst;
2092         }
2093 
2094         public void setInst(Type inst) {
2095             this.inst = inst;
2096             if (listener != null) {
2097                 listener.varInstantiated(this);
2098             }
2099         }
2100 
2101         /** get all bounds of a given kind */
2102         public List<Type> getBounds(InferenceBound... ibs) {
2103             ListBuffer<Type> buf = new ListBuffer<>();
2104             for (InferenceBound ib : ibs) {
2105                 buf.appendList(bounds.get(ib));
2106             }
2107             return buf.toList();
2108         }
2109 
2110         /** get the list of declared (upper) bounds */
2111         public List<Type> getDeclaredBounds() {
2112             ListBuffer<Type> buf = new ListBuffer<>();
2113             int count = 0;
2114             for (Type b : getBounds(InferenceBound.UPPER)) {
2115                 if (count++ == declaredCount) break;
2116                 buf.append(b);
2117             }
2118             return buf.toList();
2119         }
2120 
2121         /** internal method used to override an undetvar bounds */
2122         public void setBounds(InferenceBound ib, List<Type> newBounds) {
2123             bounds.put(ib, newBounds);
2124         }
2125 
2126         /** add a bound of a given kind - this might trigger listener notification */
2127         public final void addBound(InferenceBound ib, Type bound, Types types) {
2128             addBound(ib, bound, types, false);
2129         }
2130 
2131         @SuppressWarnings("fallthrough")
2132         private void addBound(InferenceBound ib, Type bound, Types types, boolean update) {
2133             if (kind == Kind.CAPTURED && !update) {
2134                 //Captured inference variables bounds must not be updated during incorporation,
2135                 //except when some inference variable (beta) has been instantiated in the
2136                 //right-hand-side of a 'C<alpha> = capture(C<? extends/super beta>) constraint.
2137                 if (bound.hasTag(UNDETVAR) && !((UndetVar)bound).isCaptured()) {
2138                     //If the new incoming bound is itself a (regular) inference variable,
2139                     //then we are allowed to propagate this inference variable bounds to it.
2140                     ((UndetVar)bound).addBound(ib.complement(), this, types, false);
2141                 }
2142             } else {
2143                 Type bound2 = bound.map(toTypeVarMap).baseType();
2144                 List<Type> prevBounds = bounds.get(ib);
2145                 if (bound == qtype) return;
2146                 for (Type b : prevBounds) {
2147                     //check for redundancy - do not add same bound twice
2148                     if (types.isSameType(b, bound2)) return;
2149                 }
2150                 bounds.put(ib, prevBounds.prepend(bound2));
2151                 notifyBoundChange(ib, bound2, false);
2152             }
2153         }
2154         //where
2155             TypeMapping<Void> toTypeVarMap = new StructuralTypeMapping<Void>() {
2156                 @Override
2157                 public Type visitUndetVar(UndetVar uv, Void _unused) {
2158                     return uv.inst != null ? uv.inst : uv.qtype;
2159                 }
2160             };
2161 
2162         /** replace types in all bounds - this might trigger listener notification */
2163         public void substBounds(List<Type> from, List<Type> to, Types types) {
2164             final ListBuffer<Pair<InferenceBound, Type>>  boundsChanged = new ListBuffer<>();
2165             UndetVarListener prevListener = listener;
2166             try {
2167                 //setup new listener for keeping track of changed bounds
2168                 listener = (uv, ib, t, _ignored) -> {
2169                     Assert.check(uv == UndetVar.this);
2170                     boundsChanged.add(new Pair<>(ib, t));
2171                 };
2172                 for (Map.Entry<InferenceBound, List<Type>> _entry : bounds.entrySet()) {
2173                     InferenceBound ib = _entry.getKey();
2174                     List<Type> prevBounds = _entry.getValue();
2175                     ListBuffer<Type> newBounds = new ListBuffer<>();
2176                     ListBuffer<Type> deps = new ListBuffer<>();
2177                     //step 1 - re-add bounds that are not dependent on ivars
2178                     for (Type t : prevBounds) {
2179                         if (!t.containsAny(from)) {
2180                             newBounds.append(t);
2181                         } else {
2182                             deps.append(t);
2183                         }
2184                     }
2185                     //step 2 - replace bounds
2186                     bounds.put(ib, newBounds.toList());
2187                     //step 3 - for each dependency, add new replaced bound
2188                     for (Type dep : deps) {
2189                         addBound(ib, types.subst(dep, from, to), types, true);
2190                     }
2191                 }
2192             } finally {
2193                 listener = prevListener;
2194                 for (Pair<InferenceBound, Type> boundUpdate : boundsChanged) {
2195                     notifyBoundChange(boundUpdate.fst, boundUpdate.snd, true);
2196                 }
2197             }
2198         }
2199 
2200         private void notifyBoundChange(InferenceBound ib, Type bound, boolean update) {
2201             if (listener != null) {
2202                 listener.varBoundChanged(this, ib, bound, update);
2203             }
2204         }
2205 
2206         public final boolean isCaptured() {
2207             return kind == Kind.CAPTURED;
2208         }
2209 
2210         public final boolean isThrows() {
2211             return kind == Kind.THROWS;
2212         }
2213     }
2214 
2215     /** Represents NONE.
2216      */
2217     public static class JCNoType extends Type implements NoType {
2218         public JCNoType() {
2219             // Need to use List.nil(), because JCNoType constructor
2220             // gets called in static initializers in Type, where
2221             // noAnnotations is also defined.
2222             super(null, TypeMetadata.EMPTY);
2223         }
2224 
2225         @Override
2226         public JCNoType cloneWithMetadata(TypeMetadata md) {
2227             throw new AssertionError("Cannot add metadata to a JCNoType");
2228         }
2229 
2230         @Override
2231         public TypeTag getTag() {
2232             return NONE;
2233         }
2234 
2235         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2236         public TypeKind getKind() {
2237             return TypeKind.NONE;
2238         }
2239 
2240         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2241         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
2242             return v.visitNoType(this, p);
2243         }
2244 
2245         @Override
2246         public boolean isCompound() { return false; }
2247     }
2248 
2249     /** Represents VOID.
2250      */
2251     public static class JCVoidType extends Type implements NoType {
2252 
2253         public JCVoidType() {
2254             // Void cannot be annotated
2255             super(null, TypeMetadata.EMPTY);
2256         }
2257 
2258         @Override
2259         public JCVoidType cloneWithMetadata(TypeMetadata md) {
2260             throw new AssertionError("Cannot add metadata to a void type");
2261         }
2262 
2263         @Override
2264         public TypeTag getTag() {
2265             return VOID;
2266         }
2267 
2268         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2269         public TypeKind getKind() {
2270             return TypeKind.VOID;
2271         }
2272 
2273         @Override
2274         public boolean isCompound() { return false; }
2275 
2276         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2277         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
2278             return v.visitNoType(this, p);
2279         }
2280 
2281         @Override
2282         public boolean isPrimitiveOrVoid() {
2283             return true;
2284         }
2285     }
2286 
2287     static class BottomType extends Type implements NullType {
2288         public BottomType() {
2289             // Bottom is a synthesized internal type, so it cannot be annotated
2290             super(null, TypeMetadata.EMPTY);
2291         }
2292 
2293         @Override
2294         public BottomType cloneWithMetadata(TypeMetadata md) {
2295             throw new AssertionError("Cannot add metadata to a bottom type");
2296         }
2297 
2298         @Override
2299         public TypeTag getTag() {
2300             return BOT;
2301         }
2302 
2303         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2304         public TypeKind getKind() {
2305             return TypeKind.NULL;
2306         }
2307 
2308         @Override
2309         public boolean isCompound() { return false; }
2310 
2311         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2312         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
2313             return v.visitNull(this, p);
2314         }
2315 
2316         @Override
2317         public Type constType(Object value) {
2318             return this;
2319         }
2320 
2321         @Override
2322         public String stringValue() {
2323             return "null";
2324         }
2325 
2326         @Override
2327         public boolean isNullOrReference() {
2328             return true;
2329         }
2330 
2331     }
2332 
2333     public static class ErrorType extends ClassType
2334             implements javax.lang.model.type.ErrorType {
2335 
2336         private Type originalType = null;
2337 
2338         public ErrorType(ClassSymbol c, Type originalType) {
2339             this(originalType, c);
2340             c.type = this;
2341             c.kind = ERR;
2342             c.members_field = new Scope.ErrorScope(c);
2343         }
2344 
2345         public ErrorType(Type originalType, TypeSymbol tsym) {
2346             super(noType, List.nil(), null);
2347             this.tsym = tsym;
2348             this.originalType = (originalType == null ? noType : originalType);
2349         }
2350 
2351         private ErrorType(Type originalType, TypeSymbol tsym,
2352                           TypeMetadata metadata) {
2353             super(noType, List.nil(), null, metadata);
2354             this.tsym = tsym;
2355             this.originalType = (originalType == null ? noType : originalType);
2356         }
2357 
2358         @Override
2359         public ErrorType cloneWithMetadata(TypeMetadata md) {
2360             return new ErrorType(originalType, tsym, md) {
2361                 @Override
2362                 public Type baseType() { return ErrorType.this.baseType(); }
2363             };
2364         }
2365 
2366         @Override
2367         public TypeTag getTag() {
2368             return ERROR;
2369         }
2370 
2371         @Override
2372         public boolean isPartial() {
2373             return true;
2374         }
2375 
2376         @Override
2377         public boolean isReference() {
2378             return true;
2379         }
2380 
2381         @Override
2382         public boolean isNullOrReference() {
2383             return true;
2384         }
2385 
2386         public ErrorType(Name name, TypeSymbol container, Type originalType) {
2387             this(new ClassSymbol(PUBLIC|STATIC|ACYCLIC, name, null, container), originalType);
2388         }
2389 
2390         @Override
2391         public <R,S> R accept(Type.Visitor<R,S> v, S s) {
2392             return v.visitErrorType(this, s);
2393         }
2394 
2395         public Type constType(Object constValue) { return this; }
2396         @DefinedBy(Api.LANGUAGE_MODEL)
2397         public Type getEnclosingType()           { return Type.noType; }
2398         public Type getReturnType()              { return this; }
2399         public Type asSub(Symbol sym)            { return this; }
2400 
2401         public boolean isGenType(Type t)         { return true; }
2402         public boolean isErroneous()             { return true; }
2403         public boolean isCompound()              { return false; }
2404         public boolean isInterface()             { return false; }
2405 
2406         public List<Type> allparams()            { return List.nil(); }
2407         @DefinedBy(Api.LANGUAGE_MODEL)
2408         public List<Type> getTypeArguments()     { return List.nil(); }
2409 
2410         @DefinedBy(Api.LANGUAGE_MODEL)
2411         public TypeKind getKind() {
2412             return TypeKind.ERROR;
2413         }
2414 
2415         public Type getOriginalType() {
2416             return originalType;
2417         }
2418 
2419         @DefinedBy(Api.LANGUAGE_MODEL)
2420         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
2421             return v.visitError(this, p);
2422         }
2423     }
2424 
2425     public static class UnknownType extends Type {
2426 
2427         public UnknownType() {
2428             // Unknown is a synthesized internal type, so it cannot be
2429             // annotated.
2430             super(null, TypeMetadata.EMPTY);
2431         }
2432 
2433         @Override
2434         public UnknownType cloneWithMetadata(TypeMetadata md) {
2435             throw new AssertionError("Cannot add metadata to an unknown type");
2436         }
2437 
2438         @Override
2439         public TypeTag getTag() {
2440             return UNKNOWN;
2441         }
2442 
2443         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2444         public <R, P> R accept(TypeVisitor<R, P> v, P p) {
2445             return v.visitUnknown(this, p);
2446         }
2447 
2448         @Override
2449         public boolean isPartial() {
2450             return true;
2451         }
2452     }
2453 
2454     /**
2455      * A visitor for types.  A visitor is used to implement operations
2456      * (or relations) on types.  Most common operations on types are
2457      * binary relations and this interface is designed for binary
2458      * relations, that is, operations of the form
2459      * Type&nbsp;&times;&nbsp;S&nbsp;&rarr;&nbsp;R.
2460      * <!-- In plain text: Type x S -> R -->
2461      *
2462      * @param <R> the return type of the operation implemented by this
2463      * visitor; use Void if no return type is needed.
2464      * @param <S> the type of the second argument (the first being the
2465      * type itself) of the operation implemented by this visitor; use
2466      * Void if a second argument is not needed.
2467      */
2468     public interface Visitor<R,S> {
2469         R visitClassType(ClassType t, S s);
2470         R visitWildcardType(WildcardType t, S s);
2471         R visitArrayType(ArrayType t, S s);
2472         R visitMethodType(MethodType t, S s);
2473         R visitPackageType(PackageType t, S s);
2474         R visitModuleType(ModuleType t, S s);
2475         R visitTypeVar(TypeVar t, S s);
2476         R visitCapturedType(CapturedType t, S s);
2477         R visitForAll(ForAll t, S s);
2478         R visitUndetVar(UndetVar t, S s);
2479         R visitErrorType(ErrorType t, S s);
2480         R visitType(Type t, S s);
2481     }
2482 }