1 /* 2 * Copyright (c) 2003, 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.ref.SoftReference; 29 import java.util.HashSet; 30 import java.util.HashMap; 31 import java.util.Locale; 32 import java.util.Map; 33 import java.util.Optional; 34 import java.util.Set; 35 import java.util.WeakHashMap; 36 import java.util.function.BiPredicate; 37 import java.util.function.Function; 38 import java.util.function.Predicate; 39 import java.util.stream.Collector; 40 41 import javax.tools.JavaFileObject; 42 43 import com.sun.tools.javac.code.Attribute.RetentionPolicy; 44 import com.sun.tools.javac.code.Lint.LintCategory; 45 import com.sun.tools.javac.code.Source.Feature; 46 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound; 47 import com.sun.tools.javac.code.TypeMetadata.Entry.Kind; 48 import com.sun.tools.javac.comp.AttrContext; 49 import com.sun.tools.javac.comp.Check; 50 import com.sun.tools.javac.comp.Enter; 51 import com.sun.tools.javac.comp.Env; 52 import com.sun.tools.javac.comp.LambdaToMethod; 53 import com.sun.tools.javac.jvm.ClassFile; 54 import com.sun.tools.javac.util.*; 55 56 import static com.sun.tools.javac.code.BoundKind.*; 57 import static com.sun.tools.javac.code.Flags.*; 58 import static com.sun.tools.javac.code.Kinds.Kind.*; 59 import static com.sun.tools.javac.code.Scope.*; 60 import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE; 61 import static com.sun.tools.javac.code.Symbol.*; 62 import static com.sun.tools.javac.code.Type.*; 63 import static com.sun.tools.javac.code.TypeTag.*; 64 import static com.sun.tools.javac.jvm.ClassFile.externalize; 65 import com.sun.tools.javac.resources.CompilerProperties.Fragments; 66 67 /** 68 * Utility class containing various operations on types. 69 * 70 * <p>Unless other names are more illustrative, the following naming 71 * conventions should be observed in this file: 72 * 73 * <dl> 74 * <dt>t</dt> 75 * <dd>If the first argument to an operation is a type, it should be named t.</dd> 76 * <dt>s</dt> 77 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd> 78 * <dt>ts</dt> 79 * <dd>If an operations takes a list of types, the first should be named ts.</dd> 80 * <dt>ss</dt> 81 * <dd>A second list of types should be named ss.</dd> 82 * </dl> 83 * 84 * <p><b>This is NOT part of any supported API. 85 * If you write code that depends on this, you do so at your own risk. 86 * This code and its internal interfaces are subject to change or 87 * deletion without notice.</b> 88 */ 89 public class Types { 90 protected static final Context.Key<Types> typesKey = new Context.Key<>(); 91 92 final Symtab syms; 93 final JavacMessages messages; 94 final Names names; 95 final Check chk; 96 final Enter enter; 97 JCDiagnostic.Factory diags; 98 List<Warner> warnStack = List.nil(); 99 final Name capturedName; 100 101 public final Warner noWarnings; 102 103 // <editor-fold defaultstate="collapsed" desc="Instantiating"> 104 public static Types instance(Context context) { 105 Types instance = context.get(typesKey); 106 if (instance == null) 107 instance = new Types(context); 108 return instance; 109 } 110 111 protected Types(Context context) { 112 context.put(typesKey, this); 113 syms = Symtab.instance(context); 114 names = Names.instance(context); 115 Source source = Source.instance(context); 116 chk = Check.instance(context); 117 enter = Enter.instance(context); 118 capturedName = names.fromString("<captured wildcard>"); 119 messages = JavacMessages.instance(context); 120 diags = JCDiagnostic.Factory.instance(context); 121 noWarnings = new Warner(null); 122 qualifiedSymbolCache = new HashMap<>(); 123 } 124 // </editor-fold> 125 126 // <editor-fold defaultstate="collapsed" desc="bounds"> 127 /** 128 * Get a wildcard's upper bound, returning non-wildcards unchanged. 129 * @param t a type argument, either a wildcard or a type 130 */ 131 public Type wildUpperBound(Type t) { 132 if (t.hasTag(WILDCARD)) { 133 WildcardType w = (WildcardType) t; 134 if (w.isSuperBound()) 135 return w.bound == null ? syms.objectType : w.bound.getUpperBound(); 136 else 137 return wildUpperBound(w.type); 138 } 139 else return t; 140 } 141 142 /** 143 * Get a capture variable's upper bound, returning other types unchanged. 144 * @param t a type 145 */ 146 public Type cvarUpperBound(Type t) { 147 if (t.hasTag(TYPEVAR)) { 148 TypeVar v = (TypeVar) t; 149 return v.isCaptured() ? cvarUpperBound(v.getUpperBound()) : v; 150 } 151 else return t; 152 } 153 154 /** 155 * Get a wildcard's lower bound, returning non-wildcards unchanged. 156 * @param t a type argument, either a wildcard or a type 157 */ 158 public Type wildLowerBound(Type t) { 159 if (t.hasTag(WILDCARD)) { 160 WildcardType w = (WildcardType) t; 161 return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type); 162 } 163 else return t; 164 } 165 166 /** 167 * Get a capture variable's lower bound, returning other types unchanged. 168 * @param t a type 169 */ 170 public Type cvarLowerBound(Type t) { 171 if (t.hasTag(TYPEVAR) && ((TypeVar) t).isCaptured()) { 172 return cvarLowerBound(t.getLowerBound()); 173 } 174 else return t; 175 } 176 177 /** 178 * Recursively skip type-variables until a class/array type is found; capture conversion is then 179 * (optionally) applied to the resulting type. This is useful for i.e. computing a site that is 180 * suitable for a method lookup. 181 */ 182 public Type skipTypeVars(Type site, boolean capture) { 183 while (site.hasTag(TYPEVAR)) { 184 site = site.getUpperBound(); 185 } 186 return capture ? capture(site) : site; 187 } 188 // </editor-fold> 189 190 // <editor-fold defaultstate="collapsed" desc="projections"> 191 192 /** 193 * A projection kind. See {@link TypeProjection} 194 */ 195 enum ProjectionKind { 196 UPWARDS() { 197 @Override 198 ProjectionKind complement() { 199 return DOWNWARDS; 200 } 201 }, 202 DOWNWARDS() { 203 @Override 204 ProjectionKind complement() { 205 return UPWARDS; 206 } 207 }; 208 209 abstract ProjectionKind complement(); 210 } 211 212 /** 213 * This visitor performs upwards and downwards projections on types. 214 * 215 * A projection is defined as a function that takes a type T, a set of type variables V and that 216 * produces another type S. 217 * 218 * An upwards projection maps a type T into a type S such that (i) T has no variables in V, 219 * and (ii) S is an upper bound of T. 220 * 221 * A downwards projection maps a type T into a type S such that (i) T has no variables in V, 222 * and (ii) S is a lower bound of T. 223 * 224 * Note that projections are only allowed to touch variables in V. Therefore, it is possible for 225 * a projection to leave its input type unchanged if it does not contain any variables in V. 226 * 227 * Moreover, note that while an upwards projection is always defined (every type as an upper bound), 228 * a downwards projection is not always defined. 229 * 230 * Examples: 231 * 232 * {@code upwards(List<#CAP1>, [#CAP1]) = List<? extends String>, where #CAP1 <: String } 233 * {@code downwards(List<#CAP2>, [#CAP2]) = List<? super String>, where #CAP2 :> String } 234 * {@code upwards(List<#CAP1>, [#CAP2]) = List<#CAP1> } 235 * {@code downwards(List<#CAP1>, [#CAP1]) = not defined } 236 */ 237 class TypeProjection extends TypeMapping<ProjectionKind> { 238 239 List<Type> vars; 240 Set<Type> seen = new HashSet<>(); 241 242 public TypeProjection(List<Type> vars) { 243 this.vars = vars; 244 } 245 246 @Override 247 public Type visitClassType(ClassType t, ProjectionKind pkind) { 248 if (t.isCompound()) { 249 List<Type> components = directSupertypes(t); 250 List<Type> components1 = components.map(c -> c.map(this, pkind)); 251 if (components == components1) return t; 252 else return makeIntersectionType(components1); 253 } else { 254 Type outer = t.getEnclosingType(); 255 Type outer1 = visit(outer, pkind); 256 List<Type> typarams = t.getTypeArguments(); 257 List<Type> formals = t.tsym.type.getTypeArguments(); 258 ListBuffer<Type> typarams1 = new ListBuffer<>(); 259 boolean changed = false; 260 for (Type actual : typarams) { 261 Type t2 = mapTypeArgument(t, formals.head.getUpperBound(), actual, pkind); 262 if (t2.hasTag(BOT)) { 263 //not defined 264 return syms.botType; 265 } 266 typarams1.add(t2); 267 changed |= actual != t2; 268 formals = formals.tail; 269 } 270 if (outer1 == outer && !changed) return t; 271 else return new ClassType(outer1, typarams1.toList(), t.tsym, t.getMetadata()) { 272 @Override 273 protected boolean needsStripping() { 274 return true; 275 } 276 }; 277 } 278 } 279 280 @Override 281 public Type visitArrayType(ArrayType t, ProjectionKind s) { 282 Type elemtype = t.elemtype; 283 Type elemtype1 = visit(elemtype, s); 284 if (elemtype1 == elemtype) { 285 return t; 286 } else if (elemtype1.hasTag(BOT)) { 287 //undefined 288 return syms.botType; 289 } else { 290 return new ArrayType(elemtype1, t.tsym, t.metadata) { 291 @Override 292 protected boolean needsStripping() { 293 return true; 294 } 295 }; 296 } 297 } 298 299 @Override 300 public Type visitTypeVar(TypeVar t, ProjectionKind pkind) { 301 if (vars.contains(t)) { 302 if (seen.add(t)) { 303 try { 304 final Type bound; 305 switch (pkind) { 306 case UPWARDS: 307 bound = t.getUpperBound(); 308 break; 309 case DOWNWARDS: 310 bound = (t.getLowerBound() == null) ? 311 syms.botType : 312 t.getLowerBound(); 313 break; 314 default: 315 Assert.error(); 316 return null; 317 } 318 return bound.map(this, pkind); 319 } finally { 320 seen.remove(t); 321 } 322 } else { 323 //cycle 324 return pkind == ProjectionKind.UPWARDS ? 325 syms.objectType : syms.botType; 326 } 327 } else { 328 return t; 329 } 330 } 331 332 private Type mapTypeArgument(Type site, Type declaredBound, Type t, ProjectionKind pkind) { 333 return t.containsAny(vars) ? 334 t.map(new TypeArgumentProjection(site, declaredBound), pkind) : 335 t; 336 } 337 338 class TypeArgumentProjection extends TypeMapping<ProjectionKind> { 339 340 Type site; 341 Type declaredBound; 342 343 TypeArgumentProjection(Type site, Type declaredBound) { 344 this.site = site; 345 this.declaredBound = declaredBound; 346 } 347 348 @Override 349 public Type visitType(Type t, ProjectionKind pkind) { 350 //type argument is some type containing restricted vars 351 if (pkind == ProjectionKind.DOWNWARDS) { 352 //not defined 353 return syms.botType; 354 } 355 Type upper = t.map(TypeProjection.this, ProjectionKind.UPWARDS); 356 Type lower = t.map(TypeProjection.this, ProjectionKind.DOWNWARDS); 357 List<Type> formals = site.tsym.type.getTypeArguments(); 358 BoundKind bk; 359 Type bound; 360 if (!isSameType(upper, syms.objectType) && 361 (declaredBound.containsAny(formals) || 362 !isSubtype(declaredBound, upper))) { 363 bound = upper; 364 bk = EXTENDS; 365 } else if (!lower.hasTag(BOT)) { 366 bound = lower; 367 bk = SUPER; 368 } else { 369 bound = syms.objectType; 370 bk = UNBOUND; 371 } 372 return makeWildcard(bound, bk); 373 } 374 375 @Override 376 public Type visitWildcardType(WildcardType wt, ProjectionKind pkind) { 377 //type argument is some wildcard whose bound contains restricted vars 378 Type bound = syms.botType; 379 BoundKind bk = wt.kind; 380 switch (wt.kind) { 381 case EXTENDS: 382 bound = wt.type.map(TypeProjection.this, pkind); 383 if (bound.hasTag(BOT)) { 384 return syms.botType; 385 } 386 break; 387 case SUPER: 388 bound = wt.type.map(TypeProjection.this, pkind.complement()); 389 if (bound.hasTag(BOT)) { 390 bound = syms.objectType; 391 bk = UNBOUND; 392 } 393 break; 394 } 395 return makeWildcard(bound, bk); 396 } 397 398 private Type makeWildcard(Type bound, BoundKind bk) { 399 return new WildcardType(bound, bk, syms.boundClass) { 400 @Override 401 protected boolean needsStripping() { 402 return true; 403 } 404 }; 405 } 406 } 407 } 408 409 /** 410 * Computes an upward projection of given type, and vars. See {@link TypeProjection}. 411 * 412 * @param t the type to be projected 413 * @param vars the set of type variables to be mapped 414 * @return the type obtained as result of the projection 415 */ 416 public Type upward(Type t, List<Type> vars) { 417 return t.map(new TypeProjection(vars), ProjectionKind.UPWARDS); 418 } 419 420 /** 421 * Computes the set of captured variables mentioned in a given type. See {@link CaptureScanner}. 422 * This routine is typically used to computed the input set of variables to be used during 423 * an upwards projection (see {@link Types#upward(Type, List)}). 424 * 425 * @param t the type where occurrences of captured variables have to be found 426 * @return the set of captured variables found in t 427 */ 428 public List<Type> captures(Type t) { 429 CaptureScanner cs = new CaptureScanner(); 430 Set<Type> captures = new HashSet<>(); 431 cs.visit(t, captures); 432 return List.from(captures); 433 } 434 435 /** 436 * This visitor scans a type recursively looking for occurrences of captured type variables. 437 */ 438 class CaptureScanner extends SimpleVisitor<Void, Set<Type>> { 439 440 @Override 441 public Void visitType(Type t, Set<Type> types) { 442 return null; 443 } 444 445 @Override 446 public Void visitClassType(ClassType t, Set<Type> seen) { 447 if (t.isCompound()) { 448 directSupertypes(t).forEach(s -> visit(s, seen)); 449 } else { 450 t.allparams().forEach(ta -> visit(ta, seen)); 451 } 452 return null; 453 } 454 455 @Override 456 public Void visitArrayType(ArrayType t, Set<Type> seen) { 457 return visit(t.elemtype, seen); 458 } 459 460 @Override 461 public Void visitWildcardType(WildcardType t, Set<Type> seen) { 462 visit(t.type, seen); 463 return null; 464 } 465 466 @Override 467 public Void visitTypeVar(TypeVar t, Set<Type> seen) { 468 if ((t.tsym.flags() & Flags.SYNTHETIC) != 0 && seen.add(t)) { 469 visit(t.getUpperBound(), seen); 470 } 471 return null; 472 } 473 474 @Override 475 public Void visitCapturedType(CapturedType t, Set<Type> seen) { 476 if (seen.add(t)) { 477 visit(t.getUpperBound(), seen); 478 visit(t.getLowerBound(), seen); 479 } 480 return null; 481 } 482 } 483 484 // </editor-fold> 485 486 // <editor-fold defaultstate="collapsed" desc="isUnbounded"> 487 /** 488 * Checks that all the arguments to a class are unbounded 489 * wildcards or something else that doesn't make any restrictions 490 * on the arguments. If a class isUnbounded, a raw super- or 491 * subclass can be cast to it without a warning. 492 * @param t a type 493 * @return true iff the given type is unbounded or raw 494 */ 495 public boolean isUnbounded(Type t) { 496 return isUnbounded.visit(t); 497 } 498 // where 499 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() { 500 501 public Boolean visitType(Type t, Void ignored) { 502 return true; 503 } 504 505 @Override 506 public Boolean visitClassType(ClassType t, Void ignored) { 507 List<Type> parms = t.tsym.type.allparams(); 508 List<Type> args = t.allparams(); 509 while (parms.nonEmpty()) { 510 WildcardType unb = new WildcardType(syms.objectType, 511 BoundKind.UNBOUND, 512 syms.boundClass, 513 (TypeVar)parms.head); 514 if (!containsType(args.head, unb)) 515 return false; 516 parms = parms.tail; 517 args = args.tail; 518 } 519 return true; 520 } 521 }; 522 // </editor-fold> 523 524 // <editor-fold defaultstate="collapsed" desc="asSub"> 525 /** 526 * Return the least specific subtype of t that starts with symbol 527 * sym. If none exists, return null. The least specific subtype 528 * is determined as follows: 529 * 530 * <p>If there is exactly one parameterized instance of sym that is a 531 * subtype of t, that parameterized instance is returned.<br> 532 * Otherwise, if the plain type or raw type `sym' is a subtype of 533 * type t, the type `sym' itself is returned. Otherwise, null is 534 * returned. 535 */ 536 public Type asSub(Type t, Symbol sym) { 537 return asSub.visit(t, sym); 538 } 539 // where 540 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() { 541 542 public Type visitType(Type t, Symbol sym) { 543 return null; 544 } 545 546 @Override 547 public Type visitClassType(ClassType t, Symbol sym) { 548 if (t.tsym == sym) 549 return t; 550 Type base = asSuper(sym.type, t.tsym); 551 if (base == null) 552 return null; 553 ListBuffer<Type> from = new ListBuffer<>(); 554 ListBuffer<Type> to = new ListBuffer<>(); 555 try { 556 adapt(base, t, from, to); 557 } catch (AdaptFailure ex) { 558 return null; 559 } 560 Type res = subst(sym.type, from.toList(), to.toList()); 561 if (!isSubtype(res, t)) 562 return null; 563 ListBuffer<Type> openVars = new ListBuffer<>(); 564 for (List<Type> l = sym.type.allparams(); 565 l.nonEmpty(); l = l.tail) 566 if (res.contains(l.head) && !t.contains(l.head)) 567 openVars.append(l.head); 568 if (openVars.nonEmpty()) { 569 if (t.isRaw()) { 570 // The subtype of a raw type is raw 571 res = erasure(res); 572 } else { 573 // Unbound type arguments default to ? 574 List<Type> opens = openVars.toList(); 575 ListBuffer<Type> qs = new ListBuffer<>(); 576 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) { 577 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, 578 syms.boundClass, (TypeVar) iter.head)); 579 } 580 res = subst(res, opens, qs.toList()); 581 } 582 } 583 return res; 584 } 585 586 @Override 587 public Type visitErrorType(ErrorType t, Symbol sym) { 588 return t; 589 } 590 }; 591 // </editor-fold> 592 593 // <editor-fold defaultstate="collapsed" desc="isConvertible"> 594 /** 595 * Is t a subtype of or convertible via boxing/unboxing 596 * conversion to s? 597 */ 598 public boolean isConvertible(Type t, Type s, Warner warn) { 599 if (t.hasTag(ERROR)) { 600 return true; 601 } 602 boolean tPrimitive = t.isPrimitive(); 603 boolean sPrimitive = s.isPrimitive(); 604 if (tPrimitive == sPrimitive) { 605 return isSubtypeUnchecked(t, s, warn); 606 } 607 boolean tUndet = t.hasTag(UNDETVAR); 608 boolean sUndet = s.hasTag(UNDETVAR); 609 610 if (tUndet || sUndet) { 611 return tUndet ? 612 isSubtype(t, boxedTypeOrType(s)) : 613 isSubtype(boxedTypeOrType(t), s); 614 } 615 616 return tPrimitive 617 ? isSubtype(boxedClass(t).type, s) 618 : isSubtype(unboxedType(t), s); 619 } 620 621 /** 622 * Is t a subtype of or convertible via boxing/unboxing 623 * conversions to s? 624 */ 625 public boolean isConvertible(Type t, Type s) { 626 return isConvertible(t, s, noWarnings); 627 } 628 // </editor-fold> 629 630 // <editor-fold defaultstate="collapsed" desc="findSam"> 631 632 /** 633 * Exception used to report a function descriptor lookup failure. The exception 634 * wraps a diagnostic that can be used to generate more details error 635 * messages. 636 */ 637 public static class FunctionDescriptorLookupError extends RuntimeException { 638 private static final long serialVersionUID = 0; 639 640 transient JCDiagnostic diagnostic; 641 642 FunctionDescriptorLookupError() { 643 this.diagnostic = null; 644 } 645 646 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) { 647 this.diagnostic = diag; 648 return this; 649 } 650 651 public JCDiagnostic getDiagnostic() { 652 return diagnostic; 653 } 654 655 @Override 656 public Throwable fillInStackTrace() { 657 // This is an internal exception; the stack trace is irrelevant. 658 return this; 659 } 660 } 661 662 /** 663 * A cache that keeps track of function descriptors associated with given 664 * functional interfaces. 665 */ 666 class DescriptorCache { 667 668 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<>(); 669 670 class FunctionDescriptor { 671 Symbol descSym; 672 673 FunctionDescriptor(Symbol descSym) { 674 this.descSym = descSym; 675 } 676 677 public Symbol getSymbol() { 678 return descSym; 679 } 680 681 public Type getType(Type site) { 682 site = removeWildcards(site); 683 if (site.isIntersection()) { 684 IntersectionClassType ict = (IntersectionClassType)site; 685 for (Type component : ict.getExplicitComponents()) { 686 if (!chk.checkValidGenericType(component)) { 687 //if the inferred functional interface type is not well-formed, 688 //or if it's not a subtype of the original target, issue an error 689 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site))); 690 } 691 } 692 } else { 693 if (!chk.checkValidGenericType(site)) { 694 //if the inferred functional interface type is not well-formed, 695 //or if it's not a subtype of the original target, issue an error 696 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site))); 697 } 698 } 699 return memberType(site, descSym); 700 } 701 } 702 703 class Entry { 704 final FunctionDescriptor cachedDescRes; 705 final int prevMark; 706 707 public Entry(FunctionDescriptor cachedDescRes, 708 int prevMark) { 709 this.cachedDescRes = cachedDescRes; 710 this.prevMark = prevMark; 711 } 712 713 boolean matches(int mark) { 714 return this.prevMark == mark; 715 } 716 } 717 718 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError { 719 Entry e = _map.get(origin); 720 CompoundScope members = membersClosure(origin.type, false); 721 if (e == null || 722 !e.matches(members.getMark())) { 723 FunctionDescriptor descRes = findDescriptorInternal(origin, members); 724 _map.put(origin, new Entry(descRes, members.getMark())); 725 return descRes; 726 } 727 else { 728 return e.cachedDescRes; 729 } 730 } 731 732 /** 733 * Compute the function descriptor associated with a given functional interface 734 */ 735 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin, 736 CompoundScope membersCache) throws FunctionDescriptorLookupError { 737 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0 || origin.isSealed()) { 738 //t must be an interface 739 throw failure("not.a.functional.intf", origin); 740 } 741 742 final ListBuffer<Symbol> abstracts = new ListBuffer<>(); 743 for (Symbol sym : membersCache.getSymbols(new DescriptorFilter(origin))) { 744 Type mtype = memberType(origin.type, sym); 745 if (abstracts.isEmpty()) { 746 abstracts.append(sym); 747 } else if ((sym.name == abstracts.first().name && 748 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) { 749 if (!abstracts.stream().filter(msym -> msym.owner.isSubClass(sym.enclClass(), Types.this)) 750 .map(msym -> memberType(origin.type, msym)) 751 .anyMatch(abstractMType -> isSubSignature(abstractMType, mtype))) { 752 abstracts.append(sym); 753 } 754 } else { 755 //the target method(s) should be the only abstract members of t 756 throw failure("not.a.functional.intf.1", origin, 757 diags.fragment(Fragments.IncompatibleAbstracts(Kinds.kindName(origin), origin))); 758 } 759 } 760 if (abstracts.isEmpty()) { 761 //t must define a suitable non-generic method 762 throw failure("not.a.functional.intf.1", origin, 763 diags.fragment(Fragments.NoAbstracts(Kinds.kindName(origin), origin))); 764 } else if (abstracts.size() == 1) { 765 return new FunctionDescriptor(abstracts.first()); 766 } else { // size > 1 767 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList()); 768 if (descRes == null) { 769 //we can get here if the functional interface is ill-formed 770 ListBuffer<JCDiagnostic> descriptors = new ListBuffer<>(); 771 for (Symbol desc : abstracts) { 772 String key = desc.type.getThrownTypes().nonEmpty() ? 773 "descriptor.throws" : "descriptor"; 774 descriptors.append(diags.fragment(key, desc.name, 775 desc.type.getParameterTypes(), 776 desc.type.getReturnType(), 777 desc.type.getThrownTypes())); 778 } 779 JCDiagnostic msg = 780 diags.fragment(Fragments.IncompatibleDescsInFunctionalIntf(Kinds.kindName(origin), 781 origin)); 782 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors = 783 new JCDiagnostic.MultilineDiagnostic(msg, descriptors.toList()); 784 throw failure(incompatibleDescriptors); 785 } 786 return descRes; 787 } 788 } 789 790 /** 791 * Compute a synthetic type for the target descriptor given a list 792 * of override-equivalent methods in the functional interface type. 793 * The resulting method type is a method type that is override-equivalent 794 * and return-type substitutable with each method in the original list. 795 */ 796 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) { 797 return mergeAbstracts(methodSyms, origin.type, false) 798 .map(bestSoFar -> new FunctionDescriptor(bestSoFar.baseSymbol()) { 799 @Override 800 public Type getType(Type origin) { 801 Type mt = memberType(origin, getSymbol()); 802 return createMethodTypeWithThrown(mt, bestSoFar.type.getThrownTypes()); 803 } 804 }).orElse(null); 805 } 806 807 FunctionDescriptorLookupError failure(String msg, Object... args) { 808 return failure(diags.fragment(msg, args)); 809 } 810 811 FunctionDescriptorLookupError failure(JCDiagnostic diag) { 812 return new FunctionDescriptorLookupError().setMessage(diag); 813 } 814 } 815 816 private DescriptorCache descCache = new DescriptorCache(); 817 818 /** 819 * Find the method descriptor associated to this class symbol - if the 820 * symbol 'origin' is not a functional interface, an exception is thrown. 821 */ 822 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError { 823 return descCache.get(origin).getSymbol(); 824 } 825 826 /** 827 * Find the type of the method descriptor associated to this class symbol - 828 * if the symbol 'origin' is not a functional interface, an exception is thrown. 829 */ 830 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError { 831 return descCache.get(origin.tsym).getType(origin); 832 } 833 834 /** 835 * Is given type a functional interface? 836 */ 837 public boolean isFunctionalInterface(TypeSymbol tsym) { 838 try { 839 findDescriptorSymbol(tsym); 840 return true; 841 } catch (FunctionDescriptorLookupError ex) { 842 return false; 843 } 844 } 845 846 public boolean isFunctionalInterface(Type site) { 847 try { 848 findDescriptorType(site); 849 return true; 850 } catch (FunctionDescriptorLookupError ex) { 851 return false; 852 } 853 } 854 855 public Type removeWildcards(Type site) { 856 if (site.getTypeArguments().stream().anyMatch(t -> t.hasTag(WILDCARD))) { 857 //compute non-wildcard parameterization - JLS 9.9 858 List<Type> actuals = site.getTypeArguments(); 859 List<Type> formals = site.tsym.type.getTypeArguments(); 860 ListBuffer<Type> targs = new ListBuffer<>(); 861 for (Type formal : formals) { 862 Type actual = actuals.head; 863 Type bound = formal.getUpperBound(); 864 if (actuals.head.hasTag(WILDCARD)) { 865 WildcardType wt = (WildcardType)actual; 866 //check that bound does not contain other formals 867 if (bound.containsAny(formals)) { 868 targs.add(wt.type); 869 } else { 870 //compute new type-argument based on declared bound and wildcard bound 871 switch (wt.kind) { 872 case UNBOUND: 873 targs.add(bound); 874 break; 875 case EXTENDS: 876 targs.add(glb(bound, wt.type)); 877 break; 878 case SUPER: 879 targs.add(wt.type); 880 break; 881 default: 882 Assert.error("Cannot get here!"); 883 } 884 } 885 } else { 886 //not a wildcard - the new type argument remains unchanged 887 targs.add(actual); 888 } 889 actuals = actuals.tail; 890 } 891 return subst(site.tsym.type, formals, targs.toList()); 892 } else { 893 return site; 894 } 895 } 896 897 /** 898 * Create a symbol for a class that implements a given functional interface 899 * and overrides its functional descriptor. This routine is used for two 900 * main purposes: (i) checking well-formedness of a functional interface; 901 * (ii) perform functional interface bridge calculation. 902 */ 903 public ClassSymbol makeFunctionalInterfaceClass(Env<AttrContext> env, Name name, Type target, long cflags) { 904 if (target == null || target == syms.unknownType) { 905 return null; 906 } 907 Symbol descSym = findDescriptorSymbol(target.tsym); 908 Type descType = findDescriptorType(target); 909 ClassSymbol csym = new ClassSymbol(cflags, name, env.enclClass.sym.outermostClass()); 910 csym.completer = Completer.NULL_COMPLETER; 911 csym.members_field = WriteableScope.create(csym); 912 MethodSymbol instDescSym = new MethodSymbol(descSym.flags(), descSym.name, descType, csym); 913 csym.members_field.enter(instDescSym); 914 Type.ClassType ctype = new Type.ClassType(Type.noType, List.nil(), csym); 915 ctype.supertype_field = syms.objectType; 916 ctype.interfaces_field = target.isIntersection() ? 917 directSupertypes(target) : 918 List.of(target); 919 csym.type = ctype; 920 csym.sourcefile = ((ClassSymbol)csym.owner).sourcefile; 921 return csym; 922 } 923 924 /** 925 * Find the minimal set of methods that are overridden by the functional 926 * descriptor in 'origin'. All returned methods are assumed to have different 927 * erased signatures. 928 */ 929 public List<Symbol> functionalInterfaceBridges(TypeSymbol origin) { 930 Assert.check(isFunctionalInterface(origin)); 931 Symbol descSym = findDescriptorSymbol(origin); 932 CompoundScope members = membersClosure(origin.type, false); 933 ListBuffer<Symbol> overridden = new ListBuffer<>(); 934 outer: for (Symbol m2 : members.getSymbolsByName(descSym.name, bridgeFilter)) { 935 if (m2 == descSym) continue; 936 else if (descSym.overrides(m2, origin, Types.this, false)) { 937 for (Symbol m3 : overridden) { 938 if (isSameType(m3.erasure(Types.this), m2.erasure(Types.this)) || 939 (m3.overrides(m2, origin, Types.this, false) && 940 (pendingBridges((ClassSymbol)origin, m3.enclClass()) || 941 (((MethodSymbol)m2).binaryImplementation((ClassSymbol)m3.owner, Types.this) != null)))) { 942 continue outer; 943 } 944 } 945 overridden.add(m2); 946 } 947 } 948 return overridden.toList(); 949 } 950 //where 951 // Use anonymous class instead of lambda expression intentionally, 952 // because the variable `names` has modifier: final. 953 private Predicate<Symbol> bridgeFilter = new Predicate<Symbol>() { 954 public boolean test(Symbol t) { 955 return t.kind == MTH && 956 t.name != names.init && 957 t.name != names.clinit && 958 (t.flags() & SYNTHETIC) == 0; 959 } 960 }; 961 962 private boolean pendingBridges(ClassSymbol origin, TypeSymbol s) { 963 //a symbol will be completed from a classfile if (a) symbol has 964 //an associated file object with CLASS kind and (b) the symbol has 965 //not been entered 966 if (origin.classfile != null && 967 origin.classfile.getKind() == JavaFileObject.Kind.CLASS && 968 enter.getEnv(origin) == null) { 969 return false; 970 } 971 if (origin == s) { 972 return true; 973 } 974 for (Type t : interfaces(origin.type)) { 975 if (pendingBridges((ClassSymbol)t.tsym, s)) { 976 return true; 977 } 978 } 979 return false; 980 } 981 // </editor-fold> 982 983 /** 984 * Scope filter used to skip methods that should be ignored (such as methods 985 * overridden by j.l.Object) during function interface conversion interface check 986 */ 987 class DescriptorFilter implements Predicate<Symbol> { 988 989 TypeSymbol origin; 990 991 DescriptorFilter(TypeSymbol origin) { 992 this.origin = origin; 993 } 994 995 @Override 996 public boolean test(Symbol sym) { 997 return sym.kind == MTH && 998 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT && 999 !overridesObjectMethod(origin, sym) && 1000 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0; 1001 } 1002 } 1003 1004 // <editor-fold defaultstate="collapsed" desc="isSubtype"> 1005 /** 1006 * Is t an unchecked subtype of s? 1007 */ 1008 public boolean isSubtypeUnchecked(Type t, Type s) { 1009 return isSubtypeUnchecked(t, s, noWarnings); 1010 } 1011 /** 1012 * Is t an unchecked subtype of s? 1013 */ 1014 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) { 1015 boolean result = isSubtypeUncheckedInternal(t, s, true, warn); 1016 if (result) { 1017 checkUnsafeVarargsConversion(t, s, warn); 1018 } 1019 return result; 1020 } 1021 //where 1022 private boolean isSubtypeUncheckedInternal(Type t, Type s, boolean capture, Warner warn) { 1023 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) { 1024 if (((ArrayType)t).elemtype.isPrimitive()) { 1025 return isSameType(elemtype(t), elemtype(s)); 1026 } else { 1027 return isSubtypeUncheckedInternal(elemtype(t), elemtype(s), false, warn); 1028 } 1029 } else if (isSubtype(t, s, capture)) { 1030 return true; 1031 } else if (t.hasTag(TYPEVAR)) { 1032 return isSubtypeUncheckedInternal(t.getUpperBound(), s, false, warn); 1033 } else if (!s.isRaw()) { 1034 Type t2 = asSuper(t, s.tsym); 1035 if (t2 != null && t2.isRaw()) { 1036 if (isReifiable(s)) { 1037 warn.silentWarn(LintCategory.UNCHECKED); 1038 } else { 1039 warn.warn(LintCategory.UNCHECKED); 1040 } 1041 return true; 1042 } 1043 } 1044 return false; 1045 } 1046 1047 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) { 1048 if (!t.hasTag(ARRAY) || isReifiable(t)) { 1049 return; 1050 } 1051 ArrayType from = (ArrayType)t; 1052 boolean shouldWarn = false; 1053 switch (s.getTag()) { 1054 case ARRAY: 1055 ArrayType to = (ArrayType)s; 1056 shouldWarn = from.isVarargs() && 1057 !to.isVarargs() && 1058 !isReifiable(from); 1059 break; 1060 case CLASS: 1061 shouldWarn = from.isVarargs(); 1062 break; 1063 } 1064 if (shouldWarn) { 1065 warn.warn(LintCategory.VARARGS); 1066 } 1067 } 1068 1069 /** 1070 * Is t a subtype of s?<br> 1071 * (not defined for Method and ForAll types) 1072 */ 1073 public final boolean isSubtype(Type t, Type s) { 1074 return isSubtype(t, s, true); 1075 } 1076 public final boolean isSubtypeNoCapture(Type t, Type s) { 1077 return isSubtype(t, s, false); 1078 } 1079 public boolean isSubtype(Type t, Type s, boolean capture) { 1080 if (t.equalsIgnoreMetadata(s)) 1081 return true; 1082 if (s.isPartial()) 1083 return isSuperType(s, t); 1084 1085 if (s.isCompound()) { 1086 for (Type s2 : interfaces(s).prepend(supertype(s))) { 1087 if (!isSubtype(t, s2, capture)) 1088 return false; 1089 } 1090 return true; 1091 } 1092 1093 // Generally, if 's' is a lower-bounded type variable, recur on lower bound; but 1094 // for inference variables and intersections, we need to keep 's' 1095 // (see JLS 4.10.2 for intersections and 18.2.3 for inference vars) 1096 if (!t.hasTag(UNDETVAR) && !t.isCompound()) { 1097 // TODO: JDK-8039198, bounds checking sometimes passes in a wildcard as s 1098 Type lower = cvarLowerBound(wildLowerBound(s)); 1099 if (s != lower && !lower.hasTag(BOT)) 1100 return isSubtype(capture ? capture(t) : t, lower, false); 1101 } 1102 1103 return isSubtype.visit(capture ? capture(t) : t, s); 1104 } 1105 // where 1106 private TypeRelation isSubtype = new TypeRelation() 1107 { 1108 @Override 1109 public Boolean visitType(Type t, Type s) { 1110 switch (t.getTag()) { 1111 case BYTE: 1112 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag())); 1113 case CHAR: 1114 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag())); 1115 case SHORT: case INT: case LONG: 1116 case FLOAT: case DOUBLE: 1117 return t.getTag().isSubRangeOf(s.getTag()); 1118 case BOOLEAN: case VOID: 1119 return t.hasTag(s.getTag()); 1120 case TYPEVAR: 1121 return isSubtypeNoCapture(t.getUpperBound(), s); 1122 case BOT: 1123 return 1124 s.hasTag(BOT) || s.hasTag(CLASS) || 1125 s.hasTag(ARRAY) || s.hasTag(TYPEVAR); 1126 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495) 1127 case NONE: 1128 return false; 1129 default: 1130 throw new AssertionError("isSubtype " + t.getTag()); 1131 } 1132 } 1133 1134 private Set<TypePair> cache = new HashSet<>(); 1135 1136 private boolean containsTypeRecursive(Type t, Type s) { 1137 TypePair pair = new TypePair(t, s); 1138 if (cache.add(pair)) { 1139 try { 1140 return containsType(t.getTypeArguments(), 1141 s.getTypeArguments()); 1142 } finally { 1143 cache.remove(pair); 1144 } 1145 } else { 1146 return containsType(t.getTypeArguments(), 1147 rewriteSupers(s).getTypeArguments()); 1148 } 1149 } 1150 1151 private Type rewriteSupers(Type t) { 1152 if (!t.isParameterized()) 1153 return t; 1154 ListBuffer<Type> from = new ListBuffer<>(); 1155 ListBuffer<Type> to = new ListBuffer<>(); 1156 adaptSelf(t, from, to); 1157 if (from.isEmpty()) 1158 return t; 1159 ListBuffer<Type> rewrite = new ListBuffer<>(); 1160 boolean changed = false; 1161 for (Type orig : to.toList()) { 1162 Type s = rewriteSupers(orig); 1163 if (s.isSuperBound() && !s.isExtendsBound()) { 1164 s = new WildcardType(syms.objectType, 1165 BoundKind.UNBOUND, 1166 syms.boundClass, 1167 s.getMetadata()); 1168 changed = true; 1169 } else if (s != orig) { 1170 s = new WildcardType(wildUpperBound(s), 1171 BoundKind.EXTENDS, 1172 syms.boundClass, 1173 s.getMetadata()); 1174 changed = true; 1175 } 1176 rewrite.append(s); 1177 } 1178 if (changed) 1179 return subst(t.tsym.type, from.toList(), rewrite.toList()); 1180 else 1181 return t; 1182 } 1183 1184 @Override 1185 public Boolean visitClassType(ClassType t, Type s) { 1186 Type sup = asSuper(t, s.tsym); 1187 if (sup == null) return false; 1188 // If t is an intersection, sup might not be a class type 1189 if (!sup.hasTag(CLASS)) return isSubtypeNoCapture(sup, s); 1190 return sup.tsym == s.tsym 1191 // Check type variable containment 1192 && (!s.isParameterized() || containsTypeRecursive(s, sup)) 1193 && isSubtypeNoCapture(sup.getEnclosingType(), 1194 s.getEnclosingType()); 1195 } 1196 1197 @Override 1198 public Boolean visitArrayType(ArrayType t, Type s) { 1199 if (s.hasTag(ARRAY)) { 1200 if (t.elemtype.isPrimitive()) 1201 return isSameType(t.elemtype, elemtype(s)); 1202 else 1203 return isSubtypeNoCapture(t.elemtype, elemtype(s)); 1204 } 1205 1206 if (s.hasTag(CLASS)) { 1207 Name sname = s.tsym.getQualifiedName(); 1208 return sname == names.java_lang_Object 1209 || sname == names.java_lang_Cloneable 1210 || sname == names.java_io_Serializable; 1211 } 1212 1213 return false; 1214 } 1215 1216 @Override 1217 public Boolean visitUndetVar(UndetVar t, Type s) { 1218 //todo: test against origin needed? or replace with substitution? 1219 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) { 1220 return true; 1221 } else if (s.hasTag(BOT)) { 1222 //if 's' is 'null' there's no instantiated type U for which 1223 //U <: s (but 'null' itself, which is not a valid type) 1224 return false; 1225 } 1226 1227 t.addBound(InferenceBound.UPPER, s, Types.this); 1228 return true; 1229 } 1230 1231 @Override 1232 public Boolean visitErrorType(ErrorType t, Type s) { 1233 return true; 1234 } 1235 }; 1236 1237 /** 1238 * Is t a subtype of every type in given list `ts'?<br> 1239 * (not defined for Method and ForAll types)<br> 1240 * Allows unchecked conversions. 1241 */ 1242 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) { 1243 for (List<Type> l = ts; l.nonEmpty(); l = l.tail) 1244 if (!isSubtypeUnchecked(t, l.head, warn)) 1245 return false; 1246 return true; 1247 } 1248 1249 /** 1250 * Are corresponding elements of ts subtypes of ss? If lists are 1251 * of different length, return false. 1252 */ 1253 public boolean isSubtypes(List<Type> ts, List<Type> ss) { 1254 while (ts.tail != null && ss.tail != null 1255 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ && 1256 isSubtype(ts.head, ss.head)) { 1257 ts = ts.tail; 1258 ss = ss.tail; 1259 } 1260 return ts.tail == null && ss.tail == null; 1261 /*inlined: ts.isEmpty() && ss.isEmpty();*/ 1262 } 1263 1264 /** 1265 * Are corresponding elements of ts subtypes of ss, allowing 1266 * unchecked conversions? If lists are of different length, 1267 * return false. 1268 **/ 1269 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) { 1270 while (ts.tail != null && ss.tail != null 1271 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ && 1272 isSubtypeUnchecked(ts.head, ss.head, warn)) { 1273 ts = ts.tail; 1274 ss = ss.tail; 1275 } 1276 return ts.tail == null && ss.tail == null; 1277 /*inlined: ts.isEmpty() && ss.isEmpty();*/ 1278 } 1279 // </editor-fold> 1280 1281 // <editor-fold defaultstate="collapsed" desc="isSuperType"> 1282 /** 1283 * Is t a supertype of s? 1284 */ 1285 public boolean isSuperType(Type t, Type s) { 1286 switch (t.getTag()) { 1287 case ERROR: 1288 return true; 1289 case UNDETVAR: { 1290 UndetVar undet = (UndetVar)t; 1291 if (t == s || 1292 undet.qtype == s || 1293 s.hasTag(ERROR) || 1294 s.hasTag(BOT)) { 1295 return true; 1296 } 1297 undet.addBound(InferenceBound.LOWER, s, this); 1298 return true; 1299 } 1300 default: 1301 return isSubtype(s, t); 1302 } 1303 } 1304 // </editor-fold> 1305 1306 // <editor-fold defaultstate="collapsed" desc="isSameType"> 1307 /** 1308 * Are corresponding elements of the lists the same type? If 1309 * lists are of different length, return false. 1310 */ 1311 public boolean isSameTypes(List<Type> ts, List<Type> ss) { 1312 while (ts.tail != null && ss.tail != null 1313 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ && 1314 isSameType(ts.head, ss.head)) { 1315 ts = ts.tail; 1316 ss = ss.tail; 1317 } 1318 return ts.tail == null && ss.tail == null; 1319 /*inlined: ts.isEmpty() && ss.isEmpty();*/ 1320 } 1321 1322 /** 1323 * A polymorphic signature method (JLS 15.12.3) is a method that 1324 * (i) is declared in the java.lang.invoke.MethodHandle/VarHandle classes; 1325 * (ii) takes a single variable arity parameter; 1326 * (iii) whose declared type is Object[]; 1327 * (iv) has any return type, Object signifying a polymorphic return type; and 1328 * (v) is native. 1329 */ 1330 public boolean isSignaturePolymorphic(MethodSymbol msym) { 1331 List<Type> argtypes = msym.type.getParameterTypes(); 1332 return (msym.flags_field & NATIVE) != 0 && 1333 (msym.owner == syms.methodHandleType.tsym || msym.owner == syms.varHandleType.tsym) && 1334 argtypes.length() == 1 && 1335 argtypes.head.hasTag(TypeTag.ARRAY) && 1336 ((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym; 1337 } 1338 1339 /** 1340 * Is t the same type as s? 1341 */ 1342 public boolean isSameType(Type t, Type s) { 1343 return isSameTypeVisitor.visit(t, s); 1344 } 1345 // where 1346 1347 /** 1348 * Type-equality relation - type variables are considered 1349 * equals if they share the same object identity. 1350 */ 1351 TypeRelation isSameTypeVisitor = new TypeRelation() { 1352 1353 public Boolean visitType(Type t, Type s) { 1354 if (t.equalsIgnoreMetadata(s)) 1355 return true; 1356 1357 if (s.isPartial()) 1358 return visit(s, t); 1359 1360 switch (t.getTag()) { 1361 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT: 1362 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE: 1363 return t.hasTag(s.getTag()); 1364 case TYPEVAR: { 1365 if (s.hasTag(TYPEVAR)) { 1366 //type-substitution does not preserve type-var types 1367 //check that type var symbols and bounds are indeed the same 1368 return t == s; 1369 } 1370 else { 1371 //special case for s == ? super X, where upper(s) = u 1372 //check that u == t, where u has been set by Type.withTypeVar 1373 return s.isSuperBound() && 1374 !s.isExtendsBound() && 1375 visit(t, wildUpperBound(s)); 1376 } 1377 } 1378 default: 1379 throw new AssertionError("isSameType " + t.getTag()); 1380 } 1381 } 1382 1383 @Override 1384 public Boolean visitWildcardType(WildcardType t, Type s) { 1385 if (!s.hasTag(WILDCARD)) { 1386 return false; 1387 } else { 1388 WildcardType t2 = (WildcardType)s; 1389 return (t.kind == t2.kind || (t.isExtendsBound() && s.isExtendsBound())) && 1390 isSameType(t.type, t2.type); 1391 } 1392 } 1393 1394 @Override 1395 public Boolean visitClassType(ClassType t, Type s) { 1396 if (t == s) 1397 return true; 1398 1399 if (s.isPartial()) 1400 return visit(s, t); 1401 1402 if (s.isSuperBound() && !s.isExtendsBound()) 1403 return visit(t, wildUpperBound(s)) && visit(t, wildLowerBound(s)); 1404 1405 if (t.isCompound() && s.isCompound()) { 1406 if (!visit(supertype(t), supertype(s))) 1407 return false; 1408 1409 Map<Symbol,Type> tMap = new HashMap<>(); 1410 for (Type ti : interfaces(t)) { 1411 if (tMap.containsKey(ti)) { 1412 throw new AssertionError("Malformed intersection"); 1413 } 1414 tMap.put(ti.tsym, ti); 1415 } 1416 for (Type si : interfaces(s)) { 1417 if (!tMap.containsKey(si.tsym)) 1418 return false; 1419 Type ti = tMap.remove(si.tsym); 1420 if (!visit(ti, si)) 1421 return false; 1422 } 1423 return tMap.isEmpty(); 1424 } 1425 return t.tsym == s.tsym 1426 && visit(t.getEnclosingType(), s.getEnclosingType()) 1427 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments()); 1428 } 1429 1430 @Override 1431 public Boolean visitArrayType(ArrayType t, Type s) { 1432 if (t == s) 1433 return true; 1434 1435 if (s.isPartial()) 1436 return visit(s, t); 1437 1438 return s.hasTag(ARRAY) 1439 && containsTypeEquivalent(t.elemtype, elemtype(s)); 1440 } 1441 1442 @Override 1443 public Boolean visitMethodType(MethodType t, Type s) { 1444 // isSameType for methods does not take thrown 1445 // exceptions into account! 1446 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType()); 1447 } 1448 1449 @Override 1450 public Boolean visitPackageType(PackageType t, Type s) { 1451 return t == s; 1452 } 1453 1454 @Override 1455 public Boolean visitForAll(ForAll t, Type s) { 1456 if (!s.hasTag(FORALL)) { 1457 return false; 1458 } 1459 1460 ForAll forAll = (ForAll)s; 1461 return hasSameBounds(t, forAll) 1462 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars)); 1463 } 1464 1465 @Override 1466 public Boolean visitUndetVar(UndetVar t, Type s) { 1467 if (s.hasTag(WILDCARD)) { 1468 // FIXME, this might be leftovers from before capture conversion 1469 return false; 1470 } 1471 1472 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) { 1473 return true; 1474 } 1475 1476 t.addBound(InferenceBound.EQ, s, Types.this); 1477 1478 return true; 1479 } 1480 1481 @Override 1482 public Boolean visitErrorType(ErrorType t, Type s) { 1483 return true; 1484 } 1485 }; 1486 1487 // </editor-fold> 1488 1489 // <editor-fold defaultstate="collapsed" desc="Contains Type"> 1490 public boolean containedBy(Type t, Type s) { 1491 switch (t.getTag()) { 1492 case UNDETVAR: 1493 if (s.hasTag(WILDCARD)) { 1494 UndetVar undetvar = (UndetVar)t; 1495 WildcardType wt = (WildcardType)s; 1496 switch(wt.kind) { 1497 case UNBOUND: 1498 break; 1499 case EXTENDS: { 1500 Type bound = wildUpperBound(s); 1501 undetvar.addBound(InferenceBound.UPPER, bound, this); 1502 break; 1503 } 1504 case SUPER: { 1505 Type bound = wildLowerBound(s); 1506 undetvar.addBound(InferenceBound.LOWER, bound, this); 1507 break; 1508 } 1509 } 1510 return true; 1511 } else { 1512 return isSameType(t, s); 1513 } 1514 case ERROR: 1515 return true; 1516 default: 1517 return containsType(s, t); 1518 } 1519 } 1520 1521 boolean containsType(List<Type> ts, List<Type> ss) { 1522 while (ts.nonEmpty() && ss.nonEmpty() 1523 && containsType(ts.head, ss.head)) { 1524 ts = ts.tail; 1525 ss = ss.tail; 1526 } 1527 return ts.isEmpty() && ss.isEmpty(); 1528 } 1529 1530 /** 1531 * Check if t contains s. 1532 * 1533 * <p>T contains S if: 1534 * 1535 * <p>{@code L(T) <: L(S) && U(S) <: U(T)} 1536 * 1537 * <p>This relation is only used by ClassType.isSubtype(), that 1538 * is, 1539 * 1540 * <p>{@code C<S> <: C<T> if T contains S.} 1541 * 1542 * <p>Because of F-bounds, this relation can lead to infinite 1543 * recursion. Thus we must somehow break that recursion. Notice 1544 * that containsType() is only called from ClassType.isSubtype(). 1545 * Since the arguments have already been checked against their 1546 * bounds, we know: 1547 * 1548 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)} 1549 * 1550 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)} 1551 * 1552 * @param t a type 1553 * @param s a type 1554 */ 1555 public boolean containsType(Type t, Type s) { 1556 return containsType.visit(t, s); 1557 } 1558 // where 1559 private TypeRelation containsType = new TypeRelation() { 1560 1561 public Boolean visitType(Type t, Type s) { 1562 if (s.isPartial()) 1563 return containedBy(s, t); 1564 else 1565 return isSameType(t, s); 1566 } 1567 1568 // void debugContainsType(WildcardType t, Type s) { 1569 // System.err.println(); 1570 // System.err.format(" does %s contain %s?%n", t, s); 1571 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n", 1572 // wildUpperBound(s), s, t, wildUpperBound(t), 1573 // t.isSuperBound() 1574 // || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t))); 1575 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n", 1576 // wildLowerBound(t), t, s, wildLowerBound(s), 1577 // t.isExtendsBound() 1578 // || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))); 1579 // System.err.println(); 1580 // } 1581 1582 @Override 1583 public Boolean visitWildcardType(WildcardType t, Type s) { 1584 if (s.isPartial()) 1585 return containedBy(s, t); 1586 else { 1587 // debugContainsType(t, s); 1588 return isSameWildcard(t, s) 1589 || isCaptureOf(s, t) 1590 || ((t.isExtendsBound() || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))) && 1591 (t.isSuperBound() || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t)))); 1592 } 1593 } 1594 1595 @Override 1596 public Boolean visitUndetVar(UndetVar t, Type s) { 1597 if (!s.hasTag(WILDCARD)) { 1598 return isSameType(t, s); 1599 } else { 1600 return false; 1601 } 1602 } 1603 1604 @Override 1605 public Boolean visitErrorType(ErrorType t, Type s) { 1606 return true; 1607 } 1608 }; 1609 1610 public boolean isCaptureOf(Type s, WildcardType t) { 1611 if (!s.hasTag(TYPEVAR) || !((TypeVar)s).isCaptured()) 1612 return false; 1613 return isSameWildcard(t, ((CapturedType)s).wildcard); 1614 } 1615 1616 public boolean isSameWildcard(WildcardType t, Type s) { 1617 if (!s.hasTag(WILDCARD)) 1618 return false; 1619 WildcardType w = (WildcardType)s; 1620 return w.kind == t.kind && w.type == t.type; 1621 } 1622 1623 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) { 1624 while (ts.nonEmpty() && ss.nonEmpty() 1625 && containsTypeEquivalent(ts.head, ss.head)) { 1626 ts = ts.tail; 1627 ss = ss.tail; 1628 } 1629 return ts.isEmpty() && ss.isEmpty(); 1630 } 1631 // </editor-fold> 1632 1633 // <editor-fold defaultstate="collapsed" desc="isCastable"> 1634 public boolean isCastable(Type t, Type s) { 1635 return isCastable(t, s, noWarnings); 1636 } 1637 1638 /** 1639 * Is t castable to s?<br> 1640 * s is assumed to be an erased type.<br> 1641 * (not defined for Method and ForAll types). 1642 */ 1643 public boolean isCastable(Type t, Type s, Warner warn) { 1644 // if same type 1645 if (t == s) 1646 return true; 1647 // if one of the types is primitive 1648 if (t.isPrimitive() != s.isPrimitive()) { 1649 t = skipTypeVars(t, false); 1650 return (isConvertible(t, s, warn) 1651 || (s.isPrimitive() && 1652 isSubtype(boxedClass(s).type, t))); 1653 } 1654 boolean result; 1655 if (warn != warnStack.head) { 1656 try { 1657 warnStack = warnStack.prepend(warn); 1658 checkUnsafeVarargsConversion(t, s, warn); 1659 result = isCastable.visit(t,s); 1660 } finally { 1661 warnStack = warnStack.tail; 1662 } 1663 } else { 1664 result = isCastable.visit(t,s); 1665 } 1666 if (result && t.hasTag(CLASS) && t.tsym.kind.matches(Kinds.KindSelector.TYP) 1667 && s.hasTag(CLASS) && s.tsym.kind.matches(Kinds.KindSelector.TYP) 1668 && (t.tsym.isSealed() || s.tsym.isSealed())) { 1669 return (t.isCompound() || s.isCompound()) ? 1670 true : 1671 !areDisjoint((ClassSymbol)t.tsym, (ClassSymbol)s.tsym); 1672 } 1673 return result; 1674 } 1675 // where 1676 private boolean areDisjoint(ClassSymbol ts, ClassSymbol ss) { 1677 if (isSubtype(erasure(ts.type), erasure(ss.type))) { 1678 return false; 1679 } 1680 // if both are classes or both are interfaces, shortcut 1681 if (ts.isInterface() == ss.isInterface() && isSubtype(erasure(ss.type), erasure(ts.type))) { 1682 return false; 1683 } 1684 if (ts.isInterface() && !ss.isInterface()) { 1685 /* so ts is interface but ss is a class 1686 * an interface is disjoint from a class if the class is disjoint form the interface 1687 */ 1688 return areDisjoint(ss, ts); 1689 } 1690 // a final class that is not subtype of ss is disjoint 1691 if (!ts.isInterface() && ts.isFinal()) { 1692 return true; 1693 } 1694 // if at least one is sealed 1695 if (ts.isSealed() || ss.isSealed()) { 1696 // permitted subtypes have to be disjoint with the other symbol 1697 ClassSymbol sealedOne = ts.isSealed() ? ts : ss; 1698 ClassSymbol other = sealedOne == ts ? ss : ts; 1699 return sealedOne.permitted.stream().allMatch(sym -> areDisjoint((ClassSymbol)sym, other)); 1700 } 1701 return false; 1702 } 1703 1704 private TypeRelation isCastable = new TypeRelation() { 1705 1706 public Boolean visitType(Type t, Type s) { 1707 if (s.hasTag(ERROR) || t.hasTag(NONE)) 1708 return true; 1709 1710 switch (t.getTag()) { 1711 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT: 1712 case DOUBLE: 1713 return s.isNumeric(); 1714 case BOOLEAN: 1715 return s.hasTag(BOOLEAN); 1716 case VOID: 1717 return false; 1718 case BOT: 1719 return isSubtype(t, s); 1720 default: 1721 throw new AssertionError(); 1722 } 1723 } 1724 1725 @Override 1726 public Boolean visitWildcardType(WildcardType t, Type s) { 1727 return isCastable(wildUpperBound(t), s, warnStack.head); 1728 } 1729 1730 @Override 1731 public Boolean visitClassType(ClassType t, Type s) { 1732 if (s.hasTag(ERROR) || s.hasTag(BOT)) 1733 return true; 1734 1735 if (s.hasTag(TYPEVAR)) { 1736 if (isCastable(t, s.getUpperBound(), noWarnings)) { 1737 warnStack.head.warn(LintCategory.UNCHECKED); 1738 return true; 1739 } else { 1740 return false; 1741 } 1742 } 1743 1744 if (t.isCompound() || s.isCompound()) { 1745 return !t.isCompound() ? 1746 visitCompoundType((ClassType)s, t, true) : 1747 visitCompoundType(t, s, false); 1748 } 1749 1750 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) { 1751 boolean upcast; 1752 if ((upcast = isSubtype(erasure(t), erasure(s))) 1753 || isSubtype(erasure(s), erasure(t))) { 1754 if (!upcast && s.hasTag(ARRAY)) { 1755 if (!isReifiable(s)) 1756 warnStack.head.warn(LintCategory.UNCHECKED); 1757 return true; 1758 } else if (s.isRaw()) { 1759 return true; 1760 } else if (t.isRaw()) { 1761 if (!isUnbounded(s)) 1762 warnStack.head.warn(LintCategory.UNCHECKED); 1763 return true; 1764 } 1765 // Assume |a| <: |b| 1766 final Type a = upcast ? t : s; 1767 final Type b = upcast ? s : t; 1768 final boolean HIGH = true; 1769 final boolean LOW = false; 1770 final boolean DONT_REWRITE_TYPEVARS = false; 1771 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS); 1772 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS); 1773 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS); 1774 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS); 1775 Type lowSub = asSub(bLow, aLow.tsym); 1776 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym); 1777 if (highSub == null) { 1778 final boolean REWRITE_TYPEVARS = true; 1779 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS); 1780 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS); 1781 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS); 1782 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS); 1783 lowSub = asSub(bLow, aLow.tsym); 1784 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym); 1785 } 1786 if (highSub != null) { 1787 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) { 1788 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym); 1789 } 1790 if (!disjointTypes(aHigh.allparams(), highSub.allparams()) 1791 && !disjointTypes(aHigh.allparams(), lowSub.allparams()) 1792 && !disjointTypes(aLow.allparams(), highSub.allparams()) 1793 && !disjointTypes(aLow.allparams(), lowSub.allparams())) { 1794 if (upcast ? giveWarning(a, b) : 1795 giveWarning(b, a)) 1796 warnStack.head.warn(LintCategory.UNCHECKED); 1797 return true; 1798 } 1799 } 1800 if (isReifiable(s)) 1801 return isSubtypeUnchecked(a, b); 1802 else 1803 return isSubtypeUnchecked(a, b, warnStack.head); 1804 } 1805 1806 // Sidecast 1807 if (s.hasTag(CLASS)) { 1808 if ((s.tsym.flags() & INTERFACE) != 0) { 1809 return ((t.tsym.flags() & FINAL) == 0) 1810 ? sideCast(t, s, warnStack.head) 1811 : sideCastFinal(t, s, warnStack.head); 1812 } else if ((t.tsym.flags() & INTERFACE) != 0) { 1813 return ((s.tsym.flags() & FINAL) == 0) 1814 ? sideCast(t, s, warnStack.head) 1815 : sideCastFinal(t, s, warnStack.head); 1816 } else { 1817 // unrelated class types 1818 return false; 1819 } 1820 } 1821 } 1822 return false; 1823 } 1824 1825 boolean visitCompoundType(ClassType ct, Type s, boolean reverse) { 1826 Warner warn = noWarnings; 1827 for (Type c : directSupertypes(ct)) { 1828 warn.clear(); 1829 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn)) 1830 return false; 1831 } 1832 if (warn.hasLint(LintCategory.UNCHECKED)) 1833 warnStack.head.warn(LintCategory.UNCHECKED); 1834 return true; 1835 } 1836 1837 @Override 1838 public Boolean visitArrayType(ArrayType t, Type s) { 1839 switch (s.getTag()) { 1840 case ERROR: 1841 case BOT: 1842 return true; 1843 case TYPEVAR: 1844 if (isCastable(s, t, noWarnings)) { 1845 warnStack.head.warn(LintCategory.UNCHECKED); 1846 return true; 1847 } else { 1848 return false; 1849 } 1850 case CLASS: 1851 return isSubtype(t, s); 1852 case ARRAY: 1853 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) { 1854 return elemtype(t).hasTag(elemtype(s).getTag()); 1855 } else { 1856 return isCastable(elemtype(t), elemtype(s), warnStack.head); 1857 } 1858 default: 1859 return false; 1860 } 1861 } 1862 1863 @Override 1864 public Boolean visitTypeVar(TypeVar t, Type s) { 1865 switch (s.getTag()) { 1866 case ERROR: 1867 case BOT: 1868 return true; 1869 case TYPEVAR: 1870 if (isSubtype(t, s)) { 1871 return true; 1872 } else if (isCastable(t.getUpperBound(), s, noWarnings)) { 1873 warnStack.head.warn(LintCategory.UNCHECKED); 1874 return true; 1875 } else { 1876 return false; 1877 } 1878 default: 1879 return isCastable(t.getUpperBound(), s, warnStack.head); 1880 } 1881 } 1882 1883 @Override 1884 public Boolean visitErrorType(ErrorType t, Type s) { 1885 return true; 1886 } 1887 }; 1888 // </editor-fold> 1889 1890 // <editor-fold defaultstate="collapsed" desc="disjointTypes"> 1891 public boolean disjointTypes(List<Type> ts, List<Type> ss) { 1892 while (ts.tail != null && ss.tail != null) { 1893 if (disjointType(ts.head, ss.head)) return true; 1894 ts = ts.tail; 1895 ss = ss.tail; 1896 } 1897 return false; 1898 } 1899 1900 /** 1901 * Two types or wildcards are considered disjoint if it can be 1902 * proven that no type can be contained in both. It is 1903 * conservative in that it is allowed to say that two types are 1904 * not disjoint, even though they actually are. 1905 * 1906 * The type {@code C<X>} is castable to {@code C<Y>} exactly if 1907 * {@code X} and {@code Y} are not disjoint. 1908 */ 1909 public boolean disjointType(Type t, Type s) { 1910 return disjointType.visit(t, s); 1911 } 1912 // where 1913 private TypeRelation disjointType = new TypeRelation() { 1914 1915 private Set<TypePair> cache = new HashSet<>(); 1916 1917 @Override 1918 public Boolean visitType(Type t, Type s) { 1919 if (s.hasTag(WILDCARD)) 1920 return visit(s, t); 1921 else 1922 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t); 1923 } 1924 1925 private boolean isCastableRecursive(Type t, Type s) { 1926 TypePair pair = new TypePair(t, s); 1927 if (cache.add(pair)) { 1928 try { 1929 return Types.this.isCastable(t, s); 1930 } finally { 1931 cache.remove(pair); 1932 } 1933 } else { 1934 return true; 1935 } 1936 } 1937 1938 private boolean notSoftSubtypeRecursive(Type t, Type s) { 1939 TypePair pair = new TypePair(t, s); 1940 if (cache.add(pair)) { 1941 try { 1942 return Types.this.notSoftSubtype(t, s); 1943 } finally { 1944 cache.remove(pair); 1945 } 1946 } else { 1947 return false; 1948 } 1949 } 1950 1951 @Override 1952 public Boolean visitWildcardType(WildcardType t, Type s) { 1953 if (t.isUnbound()) 1954 return false; 1955 1956 if (!s.hasTag(WILDCARD)) { 1957 if (t.isExtendsBound()) 1958 return notSoftSubtypeRecursive(s, t.type); 1959 else 1960 return notSoftSubtypeRecursive(t.type, s); 1961 } 1962 1963 if (s.isUnbound()) 1964 return false; 1965 1966 if (t.isExtendsBound()) { 1967 if (s.isExtendsBound()) 1968 return !isCastableRecursive(t.type, wildUpperBound(s)); 1969 else if (s.isSuperBound()) 1970 return notSoftSubtypeRecursive(wildLowerBound(s), t.type); 1971 } else if (t.isSuperBound()) { 1972 if (s.isExtendsBound()) 1973 return notSoftSubtypeRecursive(t.type, wildUpperBound(s)); 1974 } 1975 return false; 1976 } 1977 }; 1978 // </editor-fold> 1979 1980 // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds"> 1981 public List<Type> cvarLowerBounds(List<Type> ts) { 1982 return ts.map(cvarLowerBoundMapping); 1983 } 1984 private final TypeMapping<Void> cvarLowerBoundMapping = new TypeMapping<Void>() { 1985 @Override 1986 public Type visitCapturedType(CapturedType t, Void _unused) { 1987 return cvarLowerBound(t); 1988 } 1989 }; 1990 // </editor-fold> 1991 1992 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype"> 1993 /** 1994 * This relation answers the question: is impossible that 1995 * something of type `t' can be a subtype of `s'? This is 1996 * different from the question "is `t' not a subtype of `s'?" 1997 * when type variables are involved: Integer is not a subtype of T 1998 * where {@code <T extends Number>} but it is not true that Integer cannot 1999 * possibly be a subtype of T. 2000 */ 2001 public boolean notSoftSubtype(Type t, Type s) { 2002 if (t == s) return false; 2003 if (t.hasTag(TYPEVAR)) { 2004 TypeVar tv = (TypeVar) t; 2005 return !isCastable(tv.getUpperBound(), 2006 relaxBound(s), 2007 noWarnings); 2008 } 2009 if (!s.hasTag(WILDCARD)) 2010 s = cvarUpperBound(s); 2011 2012 return !isSubtype(t, relaxBound(s)); 2013 } 2014 2015 private Type relaxBound(Type t) { 2016 return (t.hasTag(TYPEVAR)) ? 2017 rewriteQuantifiers(skipTypeVars(t, false), true, true) : 2018 t; 2019 } 2020 // </editor-fold> 2021 2022 // <editor-fold defaultstate="collapsed" desc="isReifiable"> 2023 public boolean isReifiable(Type t) { 2024 return isReifiable.visit(t); 2025 } 2026 // where 2027 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() { 2028 2029 public Boolean visitType(Type t, Void ignored) { 2030 return true; 2031 } 2032 2033 @Override 2034 public Boolean visitClassType(ClassType t, Void ignored) { 2035 if (t.isCompound()) 2036 return false; 2037 else { 2038 if (!t.isParameterized()) 2039 return true; 2040 2041 for (Type param : t.allparams()) { 2042 if (!param.isUnbound()) 2043 return false; 2044 } 2045 return true; 2046 } 2047 } 2048 2049 @Override 2050 public Boolean visitArrayType(ArrayType t, Void ignored) { 2051 return visit(t.elemtype); 2052 } 2053 2054 @Override 2055 public Boolean visitTypeVar(TypeVar t, Void ignored) { 2056 return false; 2057 } 2058 }; 2059 // </editor-fold> 2060 2061 // <editor-fold defaultstate="collapsed" desc="Array Utils"> 2062 public boolean isArray(Type t) { 2063 while (t.hasTag(WILDCARD)) 2064 t = wildUpperBound(t); 2065 return t.hasTag(ARRAY); 2066 } 2067 2068 /** 2069 * The element type of an array. 2070 */ 2071 public Type elemtype(Type t) { 2072 switch (t.getTag()) { 2073 case WILDCARD: 2074 return elemtype(wildUpperBound(t)); 2075 case ARRAY: 2076 return ((ArrayType)t).elemtype; 2077 case FORALL: 2078 return elemtype(((ForAll)t).qtype); 2079 case ERROR: 2080 return t; 2081 default: 2082 return null; 2083 } 2084 } 2085 2086 public Type elemtypeOrType(Type t) { 2087 Type elemtype = elemtype(t); 2088 return elemtype != null ? 2089 elemtype : 2090 t; 2091 } 2092 2093 /** 2094 * Mapping to take element type of an arraytype 2095 */ 2096 private TypeMapping<Void> elemTypeFun = new TypeMapping<Void>() { 2097 @Override 2098 public Type visitArrayType(ArrayType t, Void _unused) { 2099 return t.elemtype; 2100 } 2101 2102 @Override 2103 public Type visitTypeVar(TypeVar t, Void _unused) { 2104 return visit(skipTypeVars(t, false)); 2105 } 2106 }; 2107 2108 /** 2109 * The number of dimensions of an array type. 2110 */ 2111 public int dimensions(Type t) { 2112 int result = 0; 2113 while (t.hasTag(ARRAY)) { 2114 result++; 2115 t = elemtype(t); 2116 } 2117 return result; 2118 } 2119 2120 /** 2121 * Returns an ArrayType with the component type t 2122 * 2123 * @param t The component type of the ArrayType 2124 * @return the ArrayType for the given component 2125 */ 2126 public ArrayType makeArrayType(Type t) { 2127 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) { 2128 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString()); 2129 } 2130 return new ArrayType(t, syms.arrayClass); 2131 } 2132 // </editor-fold> 2133 2134 // <editor-fold defaultstate="collapsed" desc="asSuper"> 2135 /** 2136 * Return the (most specific) base type of t that starts with the 2137 * given symbol. If none exists, return null. 2138 * 2139 * Caveat Emptor: Since javac represents the class of all arrays with a singleton 2140 * symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant, 2141 * this method could yield surprising answers when invoked on arrays. For example when 2142 * invoked with t being byte [] and sym being t.sym itself, asSuper would answer null. 2143 * 2144 * @param t a type 2145 * @param sym a symbol 2146 */ 2147 public Type asSuper(Type t, Symbol sym) { 2148 /* Some examples: 2149 * 2150 * (Enum<E>, Comparable) => Comparable<E> 2151 * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind> 2152 * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree 2153 * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) => 2154 * Iterable<capture#160 of ? extends c.s.s.d.DocTree> 2155 */ 2156 if (sym.type == syms.objectType) { //optimization 2157 return syms.objectType; 2158 } 2159 return asSuper.visit(t, sym); 2160 } 2161 // where 2162 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() { 2163 2164 private Set<Symbol> seenTypes = new HashSet<>(); 2165 2166 public Type visitType(Type t, Symbol sym) { 2167 return null; 2168 } 2169 2170 @Override 2171 public Type visitClassType(ClassType t, Symbol sym) { 2172 if (t.tsym == sym) 2173 return t; 2174 2175 Symbol c = t.tsym; 2176 if (!seenTypes.add(c)) { 2177 return null; 2178 } 2179 try { 2180 Type st = supertype(t); 2181 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) { 2182 Type x = asSuper(st, sym); 2183 if (x != null) 2184 return x; 2185 } 2186 if ((sym.flags() & INTERFACE) != 0) { 2187 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) { 2188 if (!l.head.hasTag(ERROR)) { 2189 Type x = asSuper(l.head, sym); 2190 if (x != null) 2191 return x; 2192 } 2193 } 2194 } 2195 return null; 2196 } finally { 2197 seenTypes.remove(c); 2198 } 2199 } 2200 2201 @Override 2202 public Type visitArrayType(ArrayType t, Symbol sym) { 2203 return isSubtype(t, sym.type) ? sym.type : null; 2204 } 2205 2206 @Override 2207 public Type visitTypeVar(TypeVar t, Symbol sym) { 2208 if (t.tsym == sym) 2209 return t; 2210 else 2211 return asSuper(t.getUpperBound(), sym); 2212 } 2213 2214 @Override 2215 public Type visitErrorType(ErrorType t, Symbol sym) { 2216 return t; 2217 } 2218 }; 2219 2220 /** 2221 * Return the base type of t or any of its outer types that starts 2222 * with the given symbol. If none exists, return null. 2223 * 2224 * @param t a type 2225 * @param sym a symbol 2226 */ 2227 public Type asOuterSuper(Type t, Symbol sym) { 2228 switch (t.getTag()) { 2229 case CLASS: 2230 do { 2231 Type s = asSuper(t, sym); 2232 if (s != null) return s; 2233 t = t.getEnclosingType(); 2234 } while (t.hasTag(CLASS)); 2235 return null; 2236 case ARRAY: 2237 return isSubtype(t, sym.type) ? sym.type : null; 2238 case TYPEVAR: 2239 return asSuper(t, sym); 2240 case ERROR: 2241 return t; 2242 default: 2243 return null; 2244 } 2245 } 2246 2247 /** 2248 * Return the base type of t or any of its enclosing types that 2249 * starts with the given symbol. If none exists, return null. 2250 * 2251 * @param t a type 2252 * @param sym a symbol 2253 */ 2254 public Type asEnclosingSuper(Type t, Symbol sym) { 2255 switch (t.getTag()) { 2256 case CLASS: 2257 do { 2258 Type s = asSuper(t, sym); 2259 if (s != null) return s; 2260 Type outer = t.getEnclosingType(); 2261 t = (outer.hasTag(CLASS)) ? outer : 2262 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type : 2263 Type.noType; 2264 } while (t.hasTag(CLASS)); 2265 return null; 2266 case ARRAY: 2267 return isSubtype(t, sym.type) ? sym.type : null; 2268 case TYPEVAR: 2269 return asSuper(t, sym); 2270 case ERROR: 2271 return t; 2272 default: 2273 return null; 2274 } 2275 } 2276 // </editor-fold> 2277 2278 // <editor-fold defaultstate="collapsed" desc="memberType"> 2279 /** 2280 * The type of given symbol, seen as a member of t. 2281 * 2282 * @param t a type 2283 * @param sym a symbol 2284 */ 2285 public Type memberType(Type t, Symbol sym) { 2286 return (sym.flags() & STATIC) != 0 2287 ? sym.type 2288 : memberType.visit(t, sym); 2289 } 2290 // where 2291 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() { 2292 2293 public Type visitType(Type t, Symbol sym) { 2294 return sym.type; 2295 } 2296 2297 @Override 2298 public Type visitWildcardType(WildcardType t, Symbol sym) { 2299 return memberType(wildUpperBound(t), sym); 2300 } 2301 2302 @Override 2303 public Type visitClassType(ClassType t, Symbol sym) { 2304 Symbol owner = sym.owner; 2305 long flags = sym.flags(); 2306 if (((flags & STATIC) == 0) && owner.type.isParameterized()) { 2307 Type base = asOuterSuper(t, owner); 2308 //if t is an intersection type T = CT & I1 & I2 ... & In 2309 //its supertypes CT, I1, ... In might contain wildcards 2310 //so we need to go through capture conversion 2311 base = t.isCompound() ? capture(base) : base; 2312 if (base != null) { 2313 List<Type> ownerParams = owner.type.allparams(); 2314 List<Type> baseParams = base.allparams(); 2315 if (ownerParams.nonEmpty()) { 2316 if (baseParams.isEmpty()) { 2317 // then base is a raw type 2318 return erasure(sym.type); 2319 } else { 2320 return subst(sym.type, ownerParams, baseParams); 2321 } 2322 } 2323 } 2324 } 2325 return sym.type; 2326 } 2327 2328 @Override 2329 public Type visitTypeVar(TypeVar t, Symbol sym) { 2330 return memberType(t.getUpperBound(), sym); 2331 } 2332 2333 @Override 2334 public Type visitErrorType(ErrorType t, Symbol sym) { 2335 return t; 2336 } 2337 }; 2338 // </editor-fold> 2339 2340 // <editor-fold defaultstate="collapsed" desc="isAssignable"> 2341 public boolean isAssignable(Type t, Type s) { 2342 return isAssignable(t, s, noWarnings); 2343 } 2344 2345 /** 2346 * Is t assignable to s?<br> 2347 * Equivalent to subtype except for constant values and raw 2348 * types.<br> 2349 * (not defined for Method and ForAll types) 2350 */ 2351 public boolean isAssignable(Type t, Type s, Warner warn) { 2352 if (t.hasTag(ERROR)) 2353 return true; 2354 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) { 2355 int value = ((Number)t.constValue()).intValue(); 2356 switch (s.getTag()) { 2357 case BYTE: 2358 case CHAR: 2359 case SHORT: 2360 case INT: 2361 if (s.getTag().checkRange(value)) 2362 return true; 2363 break; 2364 case CLASS: 2365 switch (unboxedType(s).getTag()) { 2366 case BYTE: 2367 case CHAR: 2368 case SHORT: 2369 return isAssignable(t, unboxedType(s), warn); 2370 } 2371 break; 2372 } 2373 } 2374 return isConvertible(t, s, warn); 2375 } 2376 // </editor-fold> 2377 2378 // <editor-fold defaultstate="collapsed" desc="erasure"> 2379 /** 2380 * The erasure of t {@code |t|} -- the type that results when all 2381 * type parameters in t are deleted. 2382 */ 2383 public Type erasure(Type t) { 2384 return eraseNotNeeded(t) ? t : erasure(t, false); 2385 } 2386 //where 2387 private boolean eraseNotNeeded(Type t) { 2388 // We don't want to erase primitive types and String type as that 2389 // operation is idempotent. Also, erasing these could result in loss 2390 // of information such as constant values attached to such types. 2391 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym); 2392 } 2393 2394 private Type erasure(Type t, boolean recurse) { 2395 if (t.isPrimitive()) { 2396 return t; /* fast special case */ 2397 } else { 2398 Type out = erasure.visit(t, recurse); 2399 return out; 2400 } 2401 } 2402 // where 2403 private TypeMapping<Boolean> erasure = new StructuralTypeMapping<Boolean>() { 2404 private Type combineMetadata(final Type s, 2405 final Type t) { 2406 if (t.getMetadata() != TypeMetadata.EMPTY) { 2407 switch (s.getKind()) { 2408 case OTHER: 2409 case UNION: 2410 case INTERSECTION: 2411 case PACKAGE: 2412 case EXECUTABLE: 2413 case NONE: 2414 case VOID: 2415 case ERROR: 2416 return s; 2417 default: return s.cloneWithMetadata(s.getMetadata().without(Kind.ANNOTATIONS)); 2418 } 2419 } else { 2420 return s; 2421 } 2422 } 2423 2424 public Type visitType(Type t, Boolean recurse) { 2425 if (t.isPrimitive()) 2426 return t; /*fast special case*/ 2427 else { 2428 //other cases already handled 2429 return combineMetadata(t, t); 2430 } 2431 } 2432 2433 @Override 2434 public Type visitWildcardType(WildcardType t, Boolean recurse) { 2435 Type erased = erasure(wildUpperBound(t), recurse); 2436 return combineMetadata(erased, t); 2437 } 2438 2439 @Override 2440 public Type visitClassType(ClassType t, Boolean recurse) { 2441 Type erased = t.tsym.erasure(Types.this); 2442 if (recurse) { 2443 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym, 2444 t.getMetadata().without(Kind.ANNOTATIONS)); 2445 return erased; 2446 } else { 2447 return combineMetadata(erased, t); 2448 } 2449 } 2450 2451 @Override 2452 public Type visitTypeVar(TypeVar t, Boolean recurse) { 2453 Type erased = erasure(t.getUpperBound(), recurse); 2454 return combineMetadata(erased, t); 2455 } 2456 }; 2457 2458 public List<Type> erasure(List<Type> ts) { 2459 return erasure.visit(ts, false); 2460 } 2461 2462 public Type erasureRecursive(Type t) { 2463 return erasure(t, true); 2464 } 2465 2466 public List<Type> erasureRecursive(List<Type> ts) { 2467 return erasure.visit(ts, true); 2468 } 2469 // </editor-fold> 2470 2471 // <editor-fold defaultstate="collapsed" desc="makeIntersectionType"> 2472 /** 2473 * Make an intersection type from non-empty list of types. The list should be ordered according to 2474 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion. 2475 * Hence, this version of makeIntersectionType may not be called during a classfile read. 2476 * 2477 * @param bounds the types from which the intersection type is formed 2478 */ 2479 public IntersectionClassType makeIntersectionType(List<Type> bounds) { 2480 return makeIntersectionType(bounds, bounds.head.tsym.isInterface()); 2481 } 2482 2483 /** 2484 * Make an intersection type from non-empty list of types. The list should be ordered according to 2485 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as 2486 * an extra parameter indicates as to whether all bounds are interfaces - in which case the 2487 * supertype is implicitly assumed to be 'Object'. 2488 * 2489 * @param bounds the types from which the intersection type is formed 2490 * @param allInterfaces are all bounds interface types? 2491 */ 2492 public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) { 2493 Assert.check(bounds.nonEmpty()); 2494 Type firstExplicitBound = bounds.head; 2495 if (allInterfaces) { 2496 bounds = bounds.prepend(syms.objectType); 2497 } 2498 ClassSymbol bc = 2499 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC, 2500 Type.moreInfo 2501 ? names.fromString(bounds.toString()) 2502 : names.empty, 2503 null, 2504 syms.noSymbol); 2505 IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces); 2506 bc.type = intersectionType; 2507 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ? 2508 syms.objectType : // error condition, recover 2509 erasure(firstExplicitBound); 2510 bc.members_field = WriteableScope.create(bc); 2511 return intersectionType; 2512 } 2513 // </editor-fold> 2514 2515 // <editor-fold defaultstate="collapsed" desc="supertype"> 2516 public Type supertype(Type t) { 2517 return supertype.visit(t); 2518 } 2519 // where 2520 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() { 2521 2522 public Type visitType(Type t, Void ignored) { 2523 // A note on wildcards: there is no good way to 2524 // determine a supertype for a lower-bounded wildcard. 2525 return Type.noType; 2526 } 2527 2528 @Override 2529 public Type visitClassType(ClassType t, Void ignored) { 2530 if (t.supertype_field == null) { 2531 Type supertype = ((ClassSymbol)t.tsym).getSuperclass(); 2532 // An interface has no superclass; its supertype is Object. 2533 if (t.isInterface()) 2534 supertype = ((ClassType)t.tsym.type).supertype_field; 2535 if (t.supertype_field == null) { 2536 List<Type> actuals = classBound(t).allparams(); 2537 List<Type> formals = t.tsym.type.allparams(); 2538 if (t.hasErasedSupertypes()) { 2539 t.supertype_field = erasureRecursive(supertype); 2540 } else if (formals.nonEmpty()) { 2541 t.supertype_field = subst(supertype, formals, actuals); 2542 } 2543 else { 2544 t.supertype_field = supertype; 2545 } 2546 } 2547 } 2548 return t.supertype_field; 2549 } 2550 2551 /** 2552 * The supertype is always a class type. If the type 2553 * variable's bounds start with a class type, this is also 2554 * the supertype. Otherwise, the supertype is 2555 * java.lang.Object. 2556 */ 2557 @Override 2558 public Type visitTypeVar(TypeVar t, Void ignored) { 2559 if (t.getUpperBound().hasTag(TYPEVAR) || 2560 (!t.getUpperBound().isCompound() && !t.getUpperBound().isInterface())) { 2561 return t.getUpperBound(); 2562 } else { 2563 return supertype(t.getUpperBound()); 2564 } 2565 } 2566 2567 @Override 2568 public Type visitArrayType(ArrayType t, Void ignored) { 2569 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType)) 2570 return arraySuperType(); 2571 else 2572 return new ArrayType(supertype(t.elemtype), t.tsym); 2573 } 2574 2575 @Override 2576 public Type visitErrorType(ErrorType t, Void ignored) { 2577 return Type.noType; 2578 } 2579 }; 2580 // </editor-fold> 2581 2582 // <editor-fold defaultstate="collapsed" desc="interfaces"> 2583 /** 2584 * Return the interfaces implemented by this class. 2585 */ 2586 public List<Type> interfaces(Type t) { 2587 return interfaces.visit(t); 2588 } 2589 // where 2590 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() { 2591 2592 public List<Type> visitType(Type t, Void ignored) { 2593 return List.nil(); 2594 } 2595 2596 @Override 2597 public List<Type> visitClassType(ClassType t, Void ignored) { 2598 if (t.interfaces_field == null) { 2599 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces(); 2600 if (t.interfaces_field == null) { 2601 // If t.interfaces_field is null, then t must 2602 // be a parameterized type (not to be confused 2603 // with a generic type declaration). 2604 // Terminology: 2605 // Parameterized type: List<String> 2606 // Generic type declaration: class List<E> { ... } 2607 // So t corresponds to List<String> and 2608 // t.tsym.type corresponds to List<E>. 2609 // The reason t must be parameterized type is 2610 // that completion will happen as a side 2611 // effect of calling 2612 // ClassSymbol.getInterfaces. Since 2613 // t.interfaces_field is null after 2614 // completion, we can assume that t is not the 2615 // type of a class/interface declaration. 2616 Assert.check(t != t.tsym.type, t); 2617 List<Type> actuals = t.allparams(); 2618 List<Type> formals = t.tsym.type.allparams(); 2619 if (t.hasErasedSupertypes()) { 2620 t.interfaces_field = erasureRecursive(interfaces); 2621 } else if (formals.nonEmpty()) { 2622 t.interfaces_field = subst(interfaces, formals, actuals); 2623 } 2624 else { 2625 t.interfaces_field = interfaces; 2626 } 2627 } 2628 } 2629 return t.interfaces_field; 2630 } 2631 2632 @Override 2633 public List<Type> visitTypeVar(TypeVar t, Void ignored) { 2634 if (t.getUpperBound().isCompound()) 2635 return interfaces(t.getUpperBound()); 2636 2637 if (t.getUpperBound().isInterface()) 2638 return List.of(t.getUpperBound()); 2639 2640 return List.nil(); 2641 } 2642 }; 2643 2644 public List<Type> directSupertypes(Type t) { 2645 return directSupertypes.visit(t); 2646 } 2647 // where 2648 private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() { 2649 2650 public List<Type> visitType(final Type type, final Void ignored) { 2651 if (!type.isIntersection()) { 2652 final Type sup = supertype(type); 2653 return (sup == Type.noType || sup == type || sup == null) 2654 ? interfaces(type) 2655 : interfaces(type).prepend(sup); 2656 } else { 2657 return ((IntersectionClassType)type).getExplicitComponents(); 2658 } 2659 } 2660 }; 2661 2662 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) { 2663 for (Type i2 : interfaces(origin.type)) { 2664 if (isym == i2.tsym) return true; 2665 } 2666 return false; 2667 } 2668 // </editor-fold> 2669 2670 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw"> 2671 Map<Type,Boolean> isDerivedRawCache = new HashMap<>(); 2672 2673 public boolean isDerivedRaw(Type t) { 2674 Boolean result = isDerivedRawCache.get(t); 2675 if (result == null) { 2676 result = isDerivedRawInternal(t); 2677 isDerivedRawCache.put(t, result); 2678 } 2679 return result; 2680 } 2681 2682 public boolean isDerivedRawInternal(Type t) { 2683 if (t.isErroneous()) 2684 return false; 2685 return 2686 t.isRaw() || 2687 supertype(t) != Type.noType && isDerivedRaw(supertype(t)) || 2688 isDerivedRaw(interfaces(t)); 2689 } 2690 2691 public boolean isDerivedRaw(List<Type> ts) { 2692 List<Type> l = ts; 2693 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail; 2694 return l.nonEmpty(); 2695 } 2696 // </editor-fold> 2697 2698 // <editor-fold defaultstate="collapsed" desc="setBounds"> 2699 /** 2700 * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly, 2701 * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise 2702 * the supertype is simply left null (in this case, the supertype is assumed to be the head of 2703 * the bound list passed as second argument). Note that this check might cause a symbol completion. 2704 * Hence, this version of setBounds may not be called during a classfile read. 2705 * 2706 * @param t a type variable 2707 * @param bounds the bounds, must be nonempty 2708 */ 2709 public void setBounds(TypeVar t, List<Type> bounds) { 2710 setBounds(t, bounds, bounds.head.tsym.isInterface()); 2711 } 2712 2713 /** 2714 * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds. 2715 * This does not cause symbol completion as an extra parameter indicates as to whether all bounds 2716 * are interfaces - in which case the supertype is implicitly assumed to be 'Object'. 2717 * 2718 * @param t a type variable 2719 * @param bounds the bounds, must be nonempty 2720 * @param allInterfaces are all bounds interface types? 2721 */ 2722 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) { 2723 t.setUpperBound( bounds.tail.isEmpty() ? 2724 bounds.head : 2725 makeIntersectionType(bounds, allInterfaces) ); 2726 t.rank_field = -1; 2727 } 2728 // </editor-fold> 2729 2730 // <editor-fold defaultstate="collapsed" desc="getBounds"> 2731 /** 2732 * Return list of bounds of the given type variable. 2733 */ 2734 public List<Type> getBounds(TypeVar t) { 2735 if (t.getUpperBound().hasTag(NONE)) 2736 return List.nil(); 2737 else if (t.getUpperBound().isErroneous() || !t.getUpperBound().isCompound()) 2738 return List.of(t.getUpperBound()); 2739 else if ((erasure(t).tsym.flags() & INTERFACE) == 0) 2740 return interfaces(t).prepend(supertype(t)); 2741 else 2742 // No superclass was given in bounds. 2743 // In this case, supertype is Object, erasure is first interface. 2744 return interfaces(t); 2745 } 2746 // </editor-fold> 2747 2748 // <editor-fold defaultstate="collapsed" desc="classBound"> 2749 /** 2750 * If the given type is a (possibly selected) type variable, 2751 * return the bounding class of this type, otherwise return the 2752 * type itself. 2753 */ 2754 public Type classBound(Type t) { 2755 return classBound.visit(t); 2756 } 2757 // where 2758 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() { 2759 2760 public Type visitType(Type t, Void ignored) { 2761 return t; 2762 } 2763 2764 @Override 2765 public Type visitClassType(ClassType t, Void ignored) { 2766 Type outer1 = classBound(t.getEnclosingType()); 2767 if (outer1 != t.getEnclosingType()) 2768 return new ClassType(outer1, t.getTypeArguments(), t.tsym, 2769 t.getMetadata()); 2770 else 2771 return t; 2772 } 2773 2774 @Override 2775 public Type visitTypeVar(TypeVar t, Void ignored) { 2776 return classBound(supertype(t)); 2777 } 2778 2779 @Override 2780 public Type visitErrorType(ErrorType t, Void ignored) { 2781 return t; 2782 } 2783 }; 2784 // </editor-fold> 2785 2786 // <editor-fold defaultstate="collapsed" desc="subsignature / override equivalence"> 2787 /** 2788 * Returns true iff the first signature is a <em>subsignature</em> 2789 * of the other. This is <b>not</b> an equivalence 2790 * relation. 2791 * 2792 * @jls 8.4.2 Method Signature 2793 * @see #overrideEquivalent(Type t, Type s) 2794 * @param t first signature (possibly raw). 2795 * @param s second signature (could be subjected to erasure). 2796 * @return true if t is a subsignature of s. 2797 */ 2798 public boolean isSubSignature(Type t, Type s) { 2799 return hasSameArgs(t, s, true) || hasSameArgs(t, erasure(s), true); 2800 } 2801 2802 /** 2803 * Returns true iff these signatures are related by <em>override 2804 * equivalence</em>. This is the natural extension of 2805 * isSubSignature to an equivalence relation. 2806 * 2807 * @jls 8.4.2 Method Signature 2808 * @see #isSubSignature(Type t, Type s) 2809 * @param t a signature (possible raw, could be subjected to 2810 * erasure). 2811 * @param s a signature (possible raw, could be subjected to 2812 * erasure). 2813 * @return true if either argument is a subsignature of the other. 2814 */ 2815 public boolean overrideEquivalent(Type t, Type s) { 2816 return hasSameArgs(t, s) || 2817 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s); 2818 } 2819 2820 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) { 2821 for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) { 2822 if (msym.overrides(sym, origin, Types.this, true)) { 2823 return true; 2824 } 2825 } 2826 return false; 2827 } 2828 2829 /** 2830 * This enum defines the strategy for implementing most specific return type check 2831 * during the most specific and functional interface checks. 2832 */ 2833 public enum MostSpecificReturnCheck { 2834 /** 2835 * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling 2836 * method type variables (if either method is generic) and (ii) subtyping should be replaced 2837 * by type-equivalence for primitives. This is essentially an inlined version of 2838 * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been 2839 * replaced with a strict subtyping check. 2840 */ 2841 BASIC() { 2842 @Override 2843 public boolean test(Type mt1, Type mt2, Types types) { 2844 List<Type> tvars = mt1.getTypeArguments(); 2845 List<Type> svars = mt2.getTypeArguments(); 2846 Type t = mt1.getReturnType(); 2847 Type s = types.subst(mt2.getReturnType(), svars, tvars); 2848 return types.isSameType(t, s) || 2849 !t.isPrimitive() && 2850 !s.isPrimitive() && 2851 types.isSubtype(t, s); 2852 } 2853 }, 2854 /** 2855 * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2. 2856 */ 2857 RTS() { 2858 @Override 2859 public boolean test(Type mt1, Type mt2, Types types) { 2860 return types.returnTypeSubstitutable(mt1, mt2); 2861 } 2862 }; 2863 2864 public abstract boolean test(Type mt1, Type mt2, Types types); 2865 } 2866 2867 /** 2868 * Merge multiple abstract methods. The preferred method is a method that is a subsignature 2869 * of all the other signatures and whose return type is more specific {@see MostSpecificReturnCheck}. 2870 * The resulting preferred method has a thrown clause that is the intersection of the merged 2871 * methods' clauses. 2872 */ 2873 public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) { 2874 //first check for preconditions 2875 boolean shouldErase = false; 2876 List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes(); 2877 for (Symbol s : ambiguousInOrder) { 2878 if ((s.flags() & ABSTRACT) == 0 || 2879 (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) { 2880 return Optional.empty(); 2881 } else if (s.type.hasTag(FORALL)) { 2882 shouldErase = true; 2883 } 2884 } 2885 //then merge abstracts 2886 for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) { 2887 outer: for (Symbol s : ambiguousInOrder) { 2888 Type mt = memberType(site, s); 2889 List<Type> allThrown = mt.getThrownTypes(); 2890 for (Symbol s2 : ambiguousInOrder) { 2891 if (s != s2) { 2892 Type mt2 = memberType(site, s2); 2893 if (!isSubSignature(mt, mt2) || 2894 !mostSpecificReturnCheck.test(mt, mt2, this)) { 2895 //ambiguity cannot be resolved 2896 continue outer; 2897 } else { 2898 List<Type> thrownTypes2 = mt2.getThrownTypes(); 2899 if (!mt.hasTag(FORALL) && shouldErase) { 2900 thrownTypes2 = erasure(thrownTypes2); 2901 } else if (mt.hasTag(FORALL)) { 2902 //subsignature implies that if most specific is generic, then all other 2903 //methods are too 2904 Assert.check(mt2.hasTag(FORALL)); 2905 // if both are generic methods, adjust thrown types ahead of intersection computation 2906 thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments()); 2907 } 2908 allThrown = chk.intersect(allThrown, thrownTypes2); 2909 } 2910 } 2911 } 2912 return (allThrown == mt.getThrownTypes()) ? 2913 Optional.of(s) : 2914 Optional.of(new MethodSymbol( 2915 s.flags(), 2916 s.name, 2917 createMethodTypeWithThrown(s.type, allThrown), 2918 s.owner) { 2919 @Override 2920 public Symbol baseSymbol() { 2921 return s; 2922 } 2923 }); 2924 } 2925 } 2926 return Optional.empty(); 2927 } 2928 2929 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site"> 2930 class ImplementationCache { 2931 2932 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>(); 2933 2934 class Entry { 2935 final MethodSymbol cachedImpl; 2936 final Predicate<Symbol> implFilter; 2937 final boolean checkResult; 2938 final int prevMark; 2939 2940 public Entry(MethodSymbol cachedImpl, 2941 Predicate<Symbol> scopeFilter, 2942 boolean checkResult, 2943 int prevMark) { 2944 this.cachedImpl = cachedImpl; 2945 this.implFilter = scopeFilter; 2946 this.checkResult = checkResult; 2947 this.prevMark = prevMark; 2948 } 2949 2950 boolean matches(Predicate<Symbol> scopeFilter, boolean checkResult, int mark) { 2951 return this.implFilter == scopeFilter && 2952 this.checkResult == checkResult && 2953 this.prevMark == mark; 2954 } 2955 } 2956 2957 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) { 2958 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms); 2959 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null; 2960 if (cache == null) { 2961 cache = new HashMap<>(); 2962 _map.put(ms, new SoftReference<>(cache)); 2963 } 2964 Entry e = cache.get(origin); 2965 CompoundScope members = membersClosure(origin.type, true); 2966 if (e == null || 2967 !e.matches(implFilter, checkResult, members.getMark())) { 2968 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter); 2969 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark())); 2970 return impl; 2971 } 2972 else { 2973 return e.cachedImpl; 2974 } 2975 } 2976 2977 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) { 2978 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) { 2979 t = skipTypeVars(t, false); 2980 TypeSymbol c = t.tsym; 2981 Symbol bestSoFar = null; 2982 for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) { 2983 if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) { 2984 bestSoFar = sym; 2985 if ((sym.flags() & ABSTRACT) == 0) { 2986 //if concrete impl is found, exit immediately 2987 break; 2988 } 2989 } 2990 } 2991 if (bestSoFar != null) { 2992 //return either the (only) concrete implementation or the first abstract one 2993 return (MethodSymbol)bestSoFar; 2994 } 2995 } 2996 return null; 2997 } 2998 } 2999 3000 private ImplementationCache implCache = new ImplementationCache(); 3001 3002 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) { 3003 return implCache.get(ms, origin, checkResult, implFilter); 3004 } 3005 // </editor-fold> 3006 3007 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site"> 3008 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> { 3009 3010 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>(); 3011 3012 Set<TypeSymbol> seenTypes = new HashSet<>(); 3013 3014 class MembersScope extends CompoundScope { 3015 3016 CompoundScope scope; 3017 3018 public MembersScope(CompoundScope scope) { 3019 super(scope.owner); 3020 this.scope = scope; 3021 } 3022 3023 Predicate<Symbol> combine(Predicate<Symbol> sf) { 3024 return s -> !s.owner.isInterface() && (sf == null || sf.test(s)); 3025 } 3026 3027 @Override 3028 public Iterable<Symbol> getSymbols(Predicate<Symbol> sf, LookupKind lookupKind) { 3029 return scope.getSymbols(combine(sf), lookupKind); 3030 } 3031 3032 @Override 3033 public Iterable<Symbol> getSymbolsByName(Name name, Predicate<Symbol> sf, LookupKind lookupKind) { 3034 return scope.getSymbolsByName(name, combine(sf), lookupKind); 3035 } 3036 3037 @Override 3038 public int getMark() { 3039 return scope.getMark(); 3040 } 3041 } 3042 3043 CompoundScope nilScope; 3044 3045 /** members closure visitor methods **/ 3046 3047 public CompoundScope visitType(Type t, Void _unused) { 3048 if (nilScope == null) { 3049 nilScope = new CompoundScope(syms.noSymbol); 3050 } 3051 return nilScope; 3052 } 3053 3054 @Override 3055 public CompoundScope visitClassType(ClassType t, Void _unused) { 3056 if (!seenTypes.add(t.tsym)) { 3057 //this is possible when an interface is implemented in multiple 3058 //superclasses, or when a class hierarchy is circular - in such 3059 //cases we don't need to recurse (empty scope is returned) 3060 return new CompoundScope(t.tsym); 3061 } 3062 try { 3063 seenTypes.add(t.tsym); 3064 ClassSymbol csym = (ClassSymbol)t.tsym; 3065 CompoundScope membersClosure = _map.get(csym); 3066 if (membersClosure == null) { 3067 membersClosure = new CompoundScope(csym); 3068 for (Type i : interfaces(t)) { 3069 membersClosure.prependSubScope(visit(i, null)); 3070 } 3071 membersClosure.prependSubScope(visit(supertype(t), null)); 3072 membersClosure.prependSubScope(csym.members()); 3073 _map.put(csym, membersClosure); 3074 } 3075 return membersClosure; 3076 } 3077 finally { 3078 seenTypes.remove(t.tsym); 3079 } 3080 } 3081 3082 @Override 3083 public CompoundScope visitTypeVar(TypeVar t, Void _unused) { 3084 return visit(t.getUpperBound(), null); 3085 } 3086 } 3087 3088 private MembersClosureCache membersCache = new MembersClosureCache(); 3089 3090 public CompoundScope membersClosure(Type site, boolean skipInterface) { 3091 CompoundScope cs = membersCache.visit(site, null); 3092 Assert.checkNonNull(cs, () -> "type " + site); 3093 return skipInterface ? membersCache.new MembersScope(cs) : cs; 3094 } 3095 // </editor-fold> 3096 3097 3098 /** Return first abstract member of class `sym'. 3099 */ 3100 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) { 3101 try { 3102 return firstUnimplementedAbstractImpl(sym, sym); 3103 } catch (CompletionFailure ex) { 3104 chk.completionError(enter.getEnv(sym).tree.pos(), ex); 3105 return null; 3106 } 3107 } 3108 //where: 3109 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) { 3110 MethodSymbol undef = null; 3111 // Do not bother to search in classes that are not abstract, 3112 // since they cannot have abstract members. 3113 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) { 3114 Scope s = c.members(); 3115 for (Symbol sym : s.getSymbols(NON_RECURSIVE)) { 3116 if (sym.kind == MTH && 3117 (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) { 3118 MethodSymbol absmeth = (MethodSymbol)sym; 3119 MethodSymbol implmeth = absmeth.implementation(impl, this, true); 3120 if (implmeth == null || implmeth == absmeth) { 3121 //look for default implementations 3122 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head; 3123 if (prov != null && prov.overrides(absmeth, impl, this, true)) { 3124 implmeth = prov; 3125 } 3126 } 3127 if (implmeth == null || implmeth == absmeth) { 3128 undef = absmeth; 3129 break; 3130 } 3131 } 3132 } 3133 if (undef == null) { 3134 Type st = supertype(c.type); 3135 if (st.hasTag(CLASS)) 3136 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym); 3137 } 3138 for (List<Type> l = interfaces(c.type); 3139 undef == null && l.nonEmpty(); 3140 l = l.tail) { 3141 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym); 3142 } 3143 } 3144 return undef; 3145 } 3146 3147 public class CandidatesCache { 3148 public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>(); 3149 3150 class Entry { 3151 Type site; 3152 MethodSymbol msym; 3153 3154 Entry(Type site, MethodSymbol msym) { 3155 this.site = site; 3156 this.msym = msym; 3157 } 3158 3159 @Override 3160 public boolean equals(Object obj) { 3161 return (obj instanceof Entry entry) 3162 && entry.msym == msym 3163 && isSameType(site, entry.site); 3164 } 3165 3166 @Override 3167 public int hashCode() { 3168 return Types.this.hashCode(site) & ~msym.hashCode(); 3169 } 3170 } 3171 3172 public List<MethodSymbol> get(Entry e) { 3173 return cache.get(e); 3174 } 3175 3176 public void put(Entry e, List<MethodSymbol> msymbols) { 3177 cache.put(e, msymbols); 3178 } 3179 } 3180 3181 public CandidatesCache candidatesCache = new CandidatesCache(); 3182 3183 //where 3184 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) { 3185 CandidatesCache.Entry e = candidatesCache.new Entry(site, ms); 3186 List<MethodSymbol> candidates = candidatesCache.get(e); 3187 if (candidates == null) { 3188 Predicate<Symbol> filter = new MethodFilter(ms, site); 3189 List<MethodSymbol> candidates2 = List.nil(); 3190 for (Symbol s : membersClosure(site, false).getSymbols(filter)) { 3191 if (!site.tsym.isInterface() && !s.owner.isInterface()) { 3192 return List.of((MethodSymbol)s); 3193 } else if (!candidates2.contains(s)) { 3194 candidates2 = candidates2.prepend((MethodSymbol)s); 3195 } 3196 } 3197 candidates = prune(candidates2); 3198 candidatesCache.put(e, candidates); 3199 } 3200 return candidates; 3201 } 3202 3203 public List<MethodSymbol> prune(List<MethodSymbol> methods) { 3204 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>(); 3205 for (MethodSymbol m1 : methods) { 3206 boolean isMin_m1 = true; 3207 for (MethodSymbol m2 : methods) { 3208 if (m1 == m2) continue; 3209 if (m2.owner != m1.owner && 3210 asSuper(m2.owner.type, m1.owner) != null) { 3211 isMin_m1 = false; 3212 break; 3213 } 3214 } 3215 if (isMin_m1) 3216 methodsMin.append(m1); 3217 } 3218 return methodsMin.toList(); 3219 } 3220 // where 3221 private class MethodFilter implements Predicate<Symbol> { 3222 3223 Symbol msym; 3224 Type site; 3225 3226 MethodFilter(Symbol msym, Type site) { 3227 this.msym = msym; 3228 this.site = site; 3229 } 3230 3231 @Override 3232 public boolean test(Symbol s) { 3233 return s.kind == MTH && 3234 s.name == msym.name && 3235 (s.flags() & SYNTHETIC) == 0 && 3236 s.isInheritedIn(site.tsym, Types.this) && 3237 overrideEquivalent(memberType(site, s), memberType(site, msym)); 3238 } 3239 } 3240 // </editor-fold> 3241 3242 /** 3243 * Does t have the same arguments as s? It is assumed that both 3244 * types are (possibly polymorphic) method types. Monomorphic 3245 * method types "have the same arguments", if their argument lists 3246 * are equal. Polymorphic method types "have the same arguments", 3247 * if they have the same arguments after renaming all type 3248 * variables of one to corresponding type variables in the other, 3249 * where correspondence is by position in the type parameter list. 3250 */ 3251 public boolean hasSameArgs(Type t, Type s) { 3252 return hasSameArgs(t, s, true); 3253 } 3254 3255 public boolean hasSameArgs(Type t, Type s, boolean strict) { 3256 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict); 3257 } 3258 3259 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) { 3260 return hasSameArgs.visit(t, s); 3261 } 3262 // where 3263 private class HasSameArgs extends TypeRelation { 3264 3265 boolean strict; 3266 3267 public HasSameArgs(boolean strict) { 3268 this.strict = strict; 3269 } 3270 3271 public Boolean visitType(Type t, Type s) { 3272 throw new AssertionError(); 3273 } 3274 3275 @Override 3276 public Boolean visitMethodType(MethodType t, Type s) { 3277 return s.hasTag(METHOD) 3278 && containsTypeEquivalent(t.argtypes, s.getParameterTypes()); 3279 } 3280 3281 @Override 3282 public Boolean visitForAll(ForAll t, Type s) { 3283 if (!s.hasTag(FORALL)) 3284 return strict ? false : visitMethodType(t.asMethodType(), s); 3285 3286 ForAll forAll = (ForAll)s; 3287 return hasSameBounds(t, forAll) 3288 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars)); 3289 } 3290 3291 @Override 3292 public Boolean visitErrorType(ErrorType t, Type s) { 3293 return false; 3294 } 3295 } 3296 3297 TypeRelation hasSameArgs_strict = new HasSameArgs(true); 3298 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false); 3299 3300 // </editor-fold> 3301 3302 // <editor-fold defaultstate="collapsed" desc="subst"> 3303 public List<Type> subst(List<Type> ts, 3304 List<Type> from, 3305 List<Type> to) { 3306 return ts.map(new Subst(from, to)); 3307 } 3308 3309 /** 3310 * Substitute all occurrences of a type in `from' with the 3311 * corresponding type in `to' in 't'. Match lists `from' and `to' 3312 * from the right: If lists have different length, discard leading 3313 * elements of the longer list. 3314 */ 3315 public Type subst(Type t, List<Type> from, List<Type> to) { 3316 return t.map(new Subst(from, to)); 3317 } 3318 3319 private class Subst extends StructuralTypeMapping<Void> { 3320 List<Type> from; 3321 List<Type> to; 3322 3323 public Subst(List<Type> from, List<Type> to) { 3324 int fromLength = from.length(); 3325 int toLength = to.length(); 3326 while (fromLength > toLength) { 3327 fromLength--; 3328 from = from.tail; 3329 } 3330 while (fromLength < toLength) { 3331 toLength--; 3332 to = to.tail; 3333 } 3334 this.from = from; 3335 this.to = to; 3336 } 3337 3338 @Override 3339 public Type visitTypeVar(TypeVar t, Void ignored) { 3340 for (List<Type> from = this.from, to = this.to; 3341 from.nonEmpty(); 3342 from = from.tail, to = to.tail) { 3343 if (t.equalsIgnoreMetadata(from.head)) { 3344 return to.head.withTypeVar(t); 3345 } 3346 } 3347 return t; 3348 } 3349 3350 @Override 3351 public Type visitClassType(ClassType t, Void ignored) { 3352 if (!t.isCompound()) { 3353 return super.visitClassType(t, ignored); 3354 } else { 3355 Type st = visit(supertype(t)); 3356 List<Type> is = visit(interfaces(t), ignored); 3357 if (st == supertype(t) && is == interfaces(t)) 3358 return t; 3359 else 3360 return makeIntersectionType(is.prepend(st)); 3361 } 3362 } 3363 3364 @Override 3365 public Type visitWildcardType(WildcardType t, Void ignored) { 3366 WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored); 3367 if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) { 3368 t2.type = wildUpperBound(t2.type); 3369 } 3370 return t2; 3371 } 3372 3373 @Override 3374 public Type visitForAll(ForAll t, Void ignored) { 3375 if (Type.containsAny(to, t.tvars)) { 3376 //perform alpha-renaming of free-variables in 't' 3377 //if 'to' types contain variables that are free in 't' 3378 List<Type> freevars = newInstances(t.tvars); 3379 t = new ForAll(freevars, 3380 Types.this.subst(t.qtype, t.tvars, freevars)); 3381 } 3382 List<Type> tvars1 = substBounds(t.tvars, from, to); 3383 Type qtype1 = visit(t.qtype); 3384 if (tvars1 == t.tvars && qtype1 == t.qtype) { 3385 return t; 3386 } else if (tvars1 == t.tvars) { 3387 return new ForAll(tvars1, qtype1) { 3388 @Override 3389 public boolean needsStripping() { 3390 return true; 3391 } 3392 }; 3393 } else { 3394 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) { 3395 @Override 3396 public boolean needsStripping() { 3397 return true; 3398 } 3399 }; 3400 } 3401 } 3402 } 3403 3404 public List<Type> substBounds(List<Type> tvars, 3405 List<Type> from, 3406 List<Type> to) { 3407 if (tvars.isEmpty()) 3408 return tvars; 3409 ListBuffer<Type> newBoundsBuf = new ListBuffer<>(); 3410 boolean changed = false; 3411 // calculate new bounds 3412 for (Type t : tvars) { 3413 TypeVar tv = (TypeVar) t; 3414 Type bound = subst(tv.getUpperBound(), from, to); 3415 if (bound != tv.getUpperBound()) 3416 changed = true; 3417 newBoundsBuf.append(bound); 3418 } 3419 if (!changed) 3420 return tvars; 3421 ListBuffer<Type> newTvars = new ListBuffer<>(); 3422 // create new type variables without bounds 3423 for (Type t : tvars) { 3424 newTvars.append(new TypeVar(t.tsym, null, syms.botType, 3425 t.getMetadata())); 3426 } 3427 // the new bounds should use the new type variables in place 3428 // of the old 3429 List<Type> newBounds = newBoundsBuf.toList(); 3430 from = tvars; 3431 to = newTvars.toList(); 3432 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) { 3433 newBounds.head = subst(newBounds.head, from, to); 3434 } 3435 newBounds = newBoundsBuf.toList(); 3436 // set the bounds of new type variables to the new bounds 3437 for (Type t : newTvars.toList()) { 3438 TypeVar tv = (TypeVar) t; 3439 tv.setUpperBound( newBounds.head ); 3440 newBounds = newBounds.tail; 3441 } 3442 return newTvars.toList(); 3443 } 3444 3445 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) { 3446 Type bound1 = subst(t.getUpperBound(), from, to); 3447 if (bound1 == t.getUpperBound()) 3448 return t; 3449 else { 3450 // create new type variable without bounds 3451 TypeVar tv = new TypeVar(t.tsym, null, syms.botType, 3452 t.getMetadata()); 3453 // the new bound should use the new type variable in place 3454 // of the old 3455 tv.setUpperBound( subst(bound1, List.of(t), List.of(tv)) ); 3456 return tv; 3457 } 3458 } 3459 // </editor-fold> 3460 3461 // <editor-fold defaultstate="collapsed" desc="hasSameBounds"> 3462 /** 3463 * Does t have the same bounds for quantified variables as s? 3464 */ 3465 public boolean hasSameBounds(ForAll t, ForAll s) { 3466 List<Type> l1 = t.tvars; 3467 List<Type> l2 = s.tvars; 3468 while (l1.nonEmpty() && l2.nonEmpty() && 3469 isSameType(l1.head.getUpperBound(), 3470 subst(l2.head.getUpperBound(), 3471 s.tvars, 3472 t.tvars))) { 3473 l1 = l1.tail; 3474 l2 = l2.tail; 3475 } 3476 return l1.isEmpty() && l2.isEmpty(); 3477 } 3478 // </editor-fold> 3479 3480 // <editor-fold defaultstate="collapsed" desc="newInstances"> 3481 /** Create new vector of type variables from list of variables 3482 * changing all recursive bounds from old to new list. 3483 */ 3484 public List<Type> newInstances(List<Type> tvars) { 3485 List<Type> tvars1 = tvars.map(newInstanceFun); 3486 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) { 3487 TypeVar tv = (TypeVar) l.head; 3488 tv.setUpperBound( subst(tv.getUpperBound(), tvars, tvars1) ); 3489 } 3490 return tvars1; 3491 } 3492 private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() { 3493 @Override 3494 public TypeVar visitTypeVar(TypeVar t, Void _unused) { 3495 return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata()); 3496 } 3497 }; 3498 // </editor-fold> 3499 3500 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) { 3501 return original.accept(methodWithParameters, newParams); 3502 } 3503 // where 3504 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() { 3505 public Type visitType(Type t, List<Type> newParams) { 3506 throw new IllegalArgumentException("Not a method type: " + t); 3507 } 3508 public Type visitMethodType(MethodType t, List<Type> newParams) { 3509 return new MethodType(newParams, t.restype, t.thrown, t.tsym); 3510 } 3511 public Type visitForAll(ForAll t, List<Type> newParams) { 3512 return new ForAll(t.tvars, t.qtype.accept(this, newParams)); 3513 } 3514 }; 3515 3516 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) { 3517 return original.accept(methodWithThrown, newThrown); 3518 } 3519 // where 3520 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() { 3521 public Type visitType(Type t, List<Type> newThrown) { 3522 throw new IllegalArgumentException("Not a method type: " + t); 3523 } 3524 public Type visitMethodType(MethodType t, List<Type> newThrown) { 3525 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym); 3526 } 3527 public Type visitForAll(ForAll t, List<Type> newThrown) { 3528 return new ForAll(t.tvars, t.qtype.accept(this, newThrown)); 3529 } 3530 }; 3531 3532 public Type createMethodTypeWithReturn(Type original, Type newReturn) { 3533 return original.accept(methodWithReturn, newReturn); 3534 } 3535 // where 3536 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() { 3537 public Type visitType(Type t, Type newReturn) { 3538 throw new IllegalArgumentException("Not a method type: " + t); 3539 } 3540 public Type visitMethodType(MethodType t, Type newReturn) { 3541 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) { 3542 @Override 3543 public Type baseType() { 3544 return t; 3545 } 3546 }; 3547 } 3548 public Type visitForAll(ForAll t, Type newReturn) { 3549 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) { 3550 @Override 3551 public Type baseType() { 3552 return t; 3553 } 3554 }; 3555 } 3556 }; 3557 3558 // <editor-fold defaultstate="collapsed" desc="createErrorType"> 3559 public Type createErrorType(Type originalType) { 3560 return new ErrorType(originalType, syms.errSymbol); 3561 } 3562 3563 public Type createErrorType(ClassSymbol c, Type originalType) { 3564 return new ErrorType(c, originalType); 3565 } 3566 3567 public Type createErrorType(Name name, TypeSymbol container, Type originalType) { 3568 return new ErrorType(name, container, originalType); 3569 } 3570 // </editor-fold> 3571 3572 // <editor-fold defaultstate="collapsed" desc="rank"> 3573 /** 3574 * The rank of a class is the length of the longest path between 3575 * the class and java.lang.Object in the class inheritance 3576 * graph. Undefined for all but reference types. 3577 */ 3578 public int rank(Type t) { 3579 switch(t.getTag()) { 3580 case CLASS: { 3581 ClassType cls = (ClassType)t; 3582 if (cls.rank_field < 0) { 3583 Name fullname = cls.tsym.getQualifiedName(); 3584 if (fullname == names.java_lang_Object) 3585 cls.rank_field = 0; 3586 else { 3587 int r = rank(supertype(cls)); 3588 for (List<Type> l = interfaces(cls); 3589 l.nonEmpty(); 3590 l = l.tail) { 3591 if (rank(l.head) > r) 3592 r = rank(l.head); 3593 } 3594 cls.rank_field = r + 1; 3595 } 3596 } 3597 return cls.rank_field; 3598 } 3599 case TYPEVAR: { 3600 TypeVar tvar = (TypeVar)t; 3601 if (tvar.rank_field < 0) { 3602 int r = rank(supertype(tvar)); 3603 for (List<Type> l = interfaces(tvar); 3604 l.nonEmpty(); 3605 l = l.tail) { 3606 if (rank(l.head) > r) r = rank(l.head); 3607 } 3608 tvar.rank_field = r + 1; 3609 } 3610 return tvar.rank_field; 3611 } 3612 case ERROR: 3613 case NONE: 3614 return 0; 3615 default: 3616 throw new AssertionError(); 3617 } 3618 } 3619 // </editor-fold> 3620 3621 /** Cache the symbol to reflect the qualifying type. 3622 * key: corresponding type 3623 * value: qualified symbol 3624 */ 3625 private Map<Type, Symbol> qualifiedSymbolCache; 3626 3627 public void clearQualifiedSymbolCache() { 3628 qualifiedSymbolCache.clear(); 3629 } 3630 3631 /** Construct a symbol to reflect the qualifying type that should 3632 * appear in the byte code as per JLS 13.1. 3633 * 3634 * For {@literal target >= 1.2}: Clone a method with the qualifier as owner (except 3635 * for those cases where we need to work around VM bugs). 3636 * 3637 * For {@literal target <= 1.1}: If qualified variable or method is defined in a 3638 * non-accessible class, clone it with the qualifier class as owner. 3639 * 3640 * @param sym The accessed symbol 3641 * @param site The qualifier's type. 3642 */ 3643 public Symbol binaryQualifier(Symbol sym, Type site) { 3644 3645 if (site.hasTag(ARRAY)) { 3646 if (sym == syms.lengthVar || 3647 sym.owner != syms.arrayClass) 3648 return sym; 3649 // array clone can be qualified by the array type in later targets 3650 Symbol qualifier; 3651 if ((qualifier = qualifiedSymbolCache.get(site)) == null) { 3652 qualifier = new ClassSymbol(Flags.PUBLIC, site.tsym.name, site, syms.noSymbol); 3653 qualifiedSymbolCache.put(site, qualifier); 3654 } 3655 return sym.clone(qualifier); 3656 } 3657 3658 if (sym.owner == site.tsym || 3659 (sym.flags() & (STATIC | SYNTHETIC)) == (STATIC | SYNTHETIC)) { 3660 return sym; 3661 } 3662 3663 // leave alone methods inherited from Object 3664 // JLS 13.1. 3665 if (sym.owner == syms.objectType.tsym) 3666 return sym; 3667 3668 return sym.clone(site.tsym); 3669 } 3670 3671 /** 3672 * Helper method for generating a string representation of a given type 3673 * accordingly to a given locale 3674 */ 3675 public String toString(Type t, Locale locale) { 3676 return Printer.createStandardPrinter(messages).visit(t, locale); 3677 } 3678 3679 /** 3680 * Helper method for generating a string representation of a given type 3681 * accordingly to a given locale 3682 */ 3683 public String toString(Symbol t, Locale locale) { 3684 return Printer.createStandardPrinter(messages).visit(t, locale); 3685 } 3686 3687 // <editor-fold defaultstate="collapsed" desc="toString"> 3688 /** 3689 * This toString is slightly more descriptive than the one on Type. 3690 * 3691 * @deprecated Types.toString(Type t, Locale l) provides better support 3692 * for localization 3693 */ 3694 @Deprecated 3695 public String toString(Type t) { 3696 if (t.hasTag(FORALL)) { 3697 ForAll forAll = (ForAll)t; 3698 return typaramsString(forAll.tvars) + forAll.qtype; 3699 } 3700 return "" + t; 3701 } 3702 // where 3703 private String typaramsString(List<Type> tvars) { 3704 StringBuilder s = new StringBuilder(); 3705 s.append('<'); 3706 boolean first = true; 3707 for (Type t : tvars) { 3708 if (!first) s.append(", "); 3709 first = false; 3710 appendTyparamString(((TypeVar)t), s); 3711 } 3712 s.append('>'); 3713 return s.toString(); 3714 } 3715 private void appendTyparamString(TypeVar t, StringBuilder buf) { 3716 buf.append(t); 3717 if (t.getUpperBound() == null || 3718 t.getUpperBound().tsym.getQualifiedName() == names.java_lang_Object) 3719 return; 3720 buf.append(" extends "); // Java syntax; no need for i18n 3721 Type bound = t.getUpperBound(); 3722 if (!bound.isCompound()) { 3723 buf.append(bound); 3724 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) { 3725 buf.append(supertype(t)); 3726 for (Type intf : interfaces(t)) { 3727 buf.append('&'); 3728 buf.append(intf); 3729 } 3730 } else { 3731 // No superclass was given in bounds. 3732 // In this case, supertype is Object, erasure is first interface. 3733 boolean first = true; 3734 for (Type intf : interfaces(t)) { 3735 if (!first) buf.append('&'); 3736 first = false; 3737 buf.append(intf); 3738 } 3739 } 3740 } 3741 // </editor-fold> 3742 3743 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types"> 3744 /** 3745 * A cache for closures. 3746 * 3747 * <p>A closure is a list of all the supertypes and interfaces of 3748 * a class or interface type, ordered by ClassSymbol.precedes 3749 * (that is, subclasses come first, arbitrary but fixed 3750 * otherwise). 3751 */ 3752 private Map<Type,List<Type>> closureCache = new HashMap<>(); 3753 3754 /** 3755 * Returns the closure of a class or interface type. 3756 */ 3757 public List<Type> closure(Type t) { 3758 List<Type> cl = closureCache.get(t); 3759 if (cl == null) { 3760 Type st = supertype(t); 3761 if (!t.isCompound()) { 3762 if (st.hasTag(CLASS)) { 3763 cl = insert(closure(st), t); 3764 } else if (st.hasTag(TYPEVAR)) { 3765 cl = closure(st).prepend(t); 3766 } else { 3767 cl = List.of(t); 3768 } 3769 } else { 3770 cl = closure(supertype(t)); 3771 } 3772 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) 3773 cl = union(cl, closure(l.head)); 3774 closureCache.put(t, cl); 3775 } 3776 return cl; 3777 } 3778 3779 /** 3780 * Collect types into a new closure (using a @code{ClosureHolder}) 3781 */ 3782 public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) { 3783 return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip), 3784 ClosureHolder::add, 3785 ClosureHolder::merge, 3786 ClosureHolder::closure); 3787 } 3788 //where 3789 class ClosureHolder { 3790 List<Type> closure; 3791 final boolean minClosure; 3792 final BiPredicate<Type, Type> shouldSkip; 3793 3794 ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) { 3795 this.closure = List.nil(); 3796 this.minClosure = minClosure; 3797 this.shouldSkip = shouldSkip; 3798 } 3799 3800 void add(Type type) { 3801 closure = insert(closure, type, shouldSkip); 3802 } 3803 3804 ClosureHolder merge(ClosureHolder other) { 3805 closure = union(closure, other.closure, shouldSkip); 3806 return this; 3807 } 3808 3809 List<Type> closure() { 3810 return minClosure ? closureMin(closure) : closure; 3811 } 3812 } 3813 3814 BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym; 3815 3816 /** 3817 * Insert a type in a closure 3818 */ 3819 public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) { 3820 if (cl.isEmpty()) { 3821 return cl.prepend(t); 3822 } else if (shouldSkip.test(t, cl.head)) { 3823 return cl; 3824 } else if (t.tsym.precedes(cl.head.tsym, this)) { 3825 return cl.prepend(t); 3826 } else { 3827 // t comes after head, or the two are unrelated 3828 return insert(cl.tail, t, shouldSkip).prepend(cl.head); 3829 } 3830 } 3831 3832 public List<Type> insert(List<Type> cl, Type t) { 3833 return insert(cl, t, basicClosureSkip); 3834 } 3835 3836 /** 3837 * Form the union of two closures 3838 */ 3839 public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) { 3840 if (cl1.isEmpty()) { 3841 return cl2; 3842 } else if (cl2.isEmpty()) { 3843 return cl1; 3844 } else if (shouldSkip.test(cl1.head, cl2.head)) { 3845 return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head); 3846 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) { 3847 return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head); 3848 } else { 3849 return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head); 3850 } 3851 } 3852 3853 public List<Type> union(List<Type> cl1, List<Type> cl2) { 3854 return union(cl1, cl2, basicClosureSkip); 3855 } 3856 3857 /** 3858 * Intersect two closures 3859 */ 3860 public List<Type> intersect(List<Type> cl1, List<Type> cl2) { 3861 if (cl1 == cl2) 3862 return cl1; 3863 if (cl1.isEmpty() || cl2.isEmpty()) 3864 return List.nil(); 3865 if (cl1.head.tsym.precedes(cl2.head.tsym, this)) 3866 return intersect(cl1.tail, cl2); 3867 if (cl2.head.tsym.precedes(cl1.head.tsym, this)) 3868 return intersect(cl1, cl2.tail); 3869 if (isSameType(cl1.head, cl2.head)) 3870 return intersect(cl1.tail, cl2.tail).prepend(cl1.head); 3871 if (cl1.head.tsym == cl2.head.tsym && 3872 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) { 3873 if (cl1.head.isParameterized() && cl2.head.isParameterized()) { 3874 Type merge = merge(cl1.head,cl2.head); 3875 return intersect(cl1.tail, cl2.tail).prepend(merge); 3876 } 3877 if (cl1.head.isRaw() || cl2.head.isRaw()) 3878 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head)); 3879 } 3880 return intersect(cl1.tail, cl2.tail); 3881 } 3882 // where 3883 class TypePair { 3884 final Type t1; 3885 final Type t2;; 3886 3887 TypePair(Type t1, Type t2) { 3888 this.t1 = t1; 3889 this.t2 = t2; 3890 } 3891 @Override 3892 public int hashCode() { 3893 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2); 3894 } 3895 @Override 3896 public boolean equals(Object obj) { 3897 return (obj instanceof TypePair typePair) 3898 && isSameType(t1, typePair.t1) 3899 && isSameType(t2, typePair.t2); 3900 } 3901 } 3902 Set<TypePair> mergeCache = new HashSet<>(); 3903 private Type merge(Type c1, Type c2) { 3904 ClassType class1 = (ClassType) c1; 3905 List<Type> act1 = class1.getTypeArguments(); 3906 ClassType class2 = (ClassType) c2; 3907 List<Type> act2 = class2.getTypeArguments(); 3908 ListBuffer<Type> merged = new ListBuffer<>(); 3909 List<Type> typarams = class1.tsym.type.getTypeArguments(); 3910 3911 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) { 3912 if (containsType(act1.head, act2.head)) { 3913 merged.append(act1.head); 3914 } else if (containsType(act2.head, act1.head)) { 3915 merged.append(act2.head); 3916 } else { 3917 TypePair pair = new TypePair(c1, c2); 3918 Type m; 3919 if (mergeCache.add(pair)) { 3920 m = new WildcardType(lub(wildUpperBound(act1.head), 3921 wildUpperBound(act2.head)), 3922 BoundKind.EXTENDS, 3923 syms.boundClass); 3924 mergeCache.remove(pair); 3925 } else { 3926 m = new WildcardType(syms.objectType, 3927 BoundKind.UNBOUND, 3928 syms.boundClass); 3929 } 3930 merged.append(m.withTypeVar(typarams.head)); 3931 } 3932 act1 = act1.tail; 3933 act2 = act2.tail; 3934 typarams = typarams.tail; 3935 } 3936 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty()); 3937 // There is no spec detailing how type annotations are to 3938 // be inherited. So set it to noAnnotations for now 3939 return new ClassType(class1.getEnclosingType(), merged.toList(), 3940 class1.tsym); 3941 } 3942 3943 /** 3944 * Return the minimum type of a closure, a compound type if no 3945 * unique minimum exists. 3946 */ 3947 private Type compoundMin(List<Type> cl) { 3948 if (cl.isEmpty()) return syms.objectType; 3949 List<Type> compound = closureMin(cl); 3950 if (compound.isEmpty()) 3951 return null; 3952 else if (compound.tail.isEmpty()) 3953 return compound.head; 3954 else 3955 return makeIntersectionType(compound); 3956 } 3957 3958 /** 3959 * Return the minimum types of a closure, suitable for computing 3960 * compoundMin or glb. 3961 */ 3962 private List<Type> closureMin(List<Type> cl) { 3963 ListBuffer<Type> classes = new ListBuffer<>(); 3964 ListBuffer<Type> interfaces = new ListBuffer<>(); 3965 Set<Type> toSkip = new HashSet<>(); 3966 while (!cl.isEmpty()) { 3967 Type current = cl.head; 3968 boolean keep = !toSkip.contains(current); 3969 if (keep && current.hasTag(TYPEVAR)) { 3970 // skip lower-bounded variables with a subtype in cl.tail 3971 for (Type t : cl.tail) { 3972 if (isSubtypeNoCapture(t, current)) { 3973 keep = false; 3974 break; 3975 } 3976 } 3977 } 3978 if (keep) { 3979 if (current.isInterface()) 3980 interfaces.append(current); 3981 else 3982 classes.append(current); 3983 for (Type t : cl.tail) { 3984 // skip supertypes of 'current' in cl.tail 3985 if (isSubtypeNoCapture(current, t)) 3986 toSkip.add(t); 3987 } 3988 } 3989 cl = cl.tail; 3990 } 3991 return classes.appendList(interfaces).toList(); 3992 } 3993 3994 /** 3995 * Return the least upper bound of list of types. if the lub does 3996 * not exist return null. 3997 */ 3998 public Type lub(List<Type> ts) { 3999 return lub(ts.toArray(new Type[ts.length()])); 4000 } 4001 4002 /** 4003 * Return the least upper bound (lub) of set of types. If the lub 4004 * does not exist return the type of null (bottom). 4005 */ 4006 public Type lub(Type... ts) { 4007 final int UNKNOWN_BOUND = 0; 4008 final int ARRAY_BOUND = 1; 4009 final int CLASS_BOUND = 2; 4010 4011 int[] kinds = new int[ts.length]; 4012 4013 int boundkind = UNKNOWN_BOUND; 4014 for (int i = 0 ; i < ts.length ; i++) { 4015 Type t = ts[i]; 4016 switch (t.getTag()) { 4017 case CLASS: 4018 boundkind |= kinds[i] = CLASS_BOUND; 4019 break; 4020 case ARRAY: 4021 boundkind |= kinds[i] = ARRAY_BOUND; 4022 break; 4023 case TYPEVAR: 4024 do { 4025 t = t.getUpperBound(); 4026 } while (t.hasTag(TYPEVAR)); 4027 if (t.hasTag(ARRAY)) { 4028 boundkind |= kinds[i] = ARRAY_BOUND; 4029 } else { 4030 boundkind |= kinds[i] = CLASS_BOUND; 4031 } 4032 break; 4033 default: 4034 kinds[i] = UNKNOWN_BOUND; 4035 if (t.isPrimitive()) 4036 return syms.errType; 4037 } 4038 } 4039 switch (boundkind) { 4040 case 0: 4041 return syms.botType; 4042 4043 case ARRAY_BOUND: 4044 // calculate lub(A[], B[]) 4045 Type[] elements = new Type[ts.length]; 4046 for (int i = 0 ; i < ts.length ; i++) { 4047 Type elem = elements[i] = elemTypeFun.apply(ts[i]); 4048 if (elem.isPrimitive()) { 4049 // if a primitive type is found, then return 4050 // arraySuperType unless all the types are the 4051 // same 4052 Type first = ts[0]; 4053 for (int j = 1 ; j < ts.length ; j++) { 4054 if (!isSameType(first, ts[j])) { 4055 // lub(int[], B[]) is Cloneable & Serializable 4056 return arraySuperType(); 4057 } 4058 } 4059 // all the array types are the same, return one 4060 // lub(int[], int[]) is int[] 4061 return first; 4062 } 4063 } 4064 // lub(A[], B[]) is lub(A, B)[] 4065 return new ArrayType(lub(elements), syms.arrayClass); 4066 4067 case CLASS_BOUND: 4068 // calculate lub(A, B) 4069 int startIdx = 0; 4070 for (int i = 0; i < ts.length ; i++) { 4071 Type t = ts[i]; 4072 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) { 4073 break; 4074 } else { 4075 startIdx++; 4076 } 4077 } 4078 Assert.check(startIdx < ts.length); 4079 //step 1 - compute erased candidate set (EC) 4080 List<Type> cl = erasedSupertypes(ts[startIdx]); 4081 for (int i = startIdx + 1 ; i < ts.length ; i++) { 4082 Type t = ts[i]; 4083 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) 4084 cl = intersect(cl, erasedSupertypes(t)); 4085 } 4086 //step 2 - compute minimal erased candidate set (MEC) 4087 List<Type> mec = closureMin(cl); 4088 //step 3 - for each element G in MEC, compute lci(Inv(G)) 4089 List<Type> candidates = List.nil(); 4090 for (Type erasedSupertype : mec) { 4091 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym)); 4092 for (int i = startIdx + 1 ; i < ts.length ; i++) { 4093 Type superType = asSuper(ts[i], erasedSupertype.tsym); 4094 lci = intersect(lci, superType != null ? List.of(superType) : List.nil()); 4095 } 4096 candidates = candidates.appendList(lci); 4097 } 4098 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that 4099 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn)) 4100 return compoundMin(candidates); 4101 4102 default: 4103 // calculate lub(A, B[]) 4104 List<Type> classes = List.of(arraySuperType()); 4105 for (int i = 0 ; i < ts.length ; i++) { 4106 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays 4107 classes = classes.prepend(ts[i]); 4108 } 4109 // lub(A, B[]) is lub(A, arraySuperType) 4110 return lub(classes); 4111 } 4112 } 4113 // where 4114 List<Type> erasedSupertypes(Type t) { 4115 ListBuffer<Type> buf = new ListBuffer<>(); 4116 for (Type sup : closure(t)) { 4117 if (sup.hasTag(TYPEVAR)) { 4118 buf.append(sup); 4119 } else { 4120 buf.append(erasure(sup)); 4121 } 4122 } 4123 return buf.toList(); 4124 } 4125 4126 private Type arraySuperType; 4127 private Type arraySuperType() { 4128 // initialized lazily to avoid problems during compiler startup 4129 if (arraySuperType == null) { 4130 // JLS 10.8: all arrays implement Cloneable and Serializable. 4131 arraySuperType = makeIntersectionType(List.of(syms.serializableType, 4132 syms.cloneableType), true); 4133 } 4134 return arraySuperType; 4135 } 4136 // </editor-fold> 4137 4138 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound"> 4139 public Type glb(List<Type> ts) { 4140 Type t1 = ts.head; 4141 for (Type t2 : ts.tail) { 4142 if (t1.isErroneous()) 4143 return t1; 4144 t1 = glb(t1, t2); 4145 } 4146 return t1; 4147 } 4148 //where 4149 public Type glb(Type t, Type s) { 4150 if (s == null) 4151 return t; 4152 else if (t.isPrimitive() || s.isPrimitive()) 4153 return syms.errType; 4154 else if (isSubtypeNoCapture(t, s)) 4155 return t; 4156 else if (isSubtypeNoCapture(s, t)) 4157 return s; 4158 4159 List<Type> closure = union(closure(t), closure(s)); 4160 return glbFlattened(closure, t); 4161 } 4162 //where 4163 /** 4164 * Perform glb for a list of non-primitive, non-error, non-compound types; 4165 * redundant elements are removed. Bounds should be ordered according to 4166 * {@link Symbol#precedes(TypeSymbol,Types)}. 4167 * 4168 * @param flatBounds List of type to glb 4169 * @param errT Original type to use if the result is an error type 4170 */ 4171 private Type glbFlattened(List<Type> flatBounds, Type errT) { 4172 List<Type> bounds = closureMin(flatBounds); 4173 4174 if (bounds.isEmpty()) { // length == 0 4175 return syms.objectType; 4176 } else if (bounds.tail.isEmpty()) { // length == 1 4177 return bounds.head; 4178 } else { // length > 1 4179 int classCount = 0; 4180 List<Type> cvars = List.nil(); 4181 List<Type> lowers = List.nil(); 4182 for (Type bound : bounds) { 4183 if (!bound.isInterface()) { 4184 classCount++; 4185 Type lower = cvarLowerBound(bound); 4186 if (bound != lower && !lower.hasTag(BOT)) { 4187 cvars = cvars.append(bound); 4188 lowers = lowers.append(lower); 4189 } 4190 } 4191 } 4192 if (classCount > 1) { 4193 if (lowers.isEmpty()) { 4194 return createErrorType(errT); 4195 } else { 4196 // try again with lower bounds included instead of capture variables 4197 List<Type> newBounds = bounds.diff(cvars).appendList(lowers); 4198 return glb(newBounds); 4199 } 4200 } 4201 } 4202 return makeIntersectionType(bounds); 4203 } 4204 // </editor-fold> 4205 4206 // <editor-fold defaultstate="collapsed" desc="hashCode"> 4207 /** 4208 * Compute a hash code on a type. 4209 */ 4210 public int hashCode(Type t) { 4211 return hashCode(t, false); 4212 } 4213 4214 public int hashCode(Type t, boolean strict) { 4215 return strict ? 4216 hashCodeStrictVisitor.visit(t) : 4217 hashCodeVisitor.visit(t); 4218 } 4219 // where 4220 private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor(); 4221 private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() { 4222 @Override 4223 public Integer visitTypeVar(TypeVar t, Void ignored) { 4224 return System.identityHashCode(t); 4225 } 4226 }; 4227 4228 private static class HashCodeVisitor extends UnaryVisitor<Integer> { 4229 public Integer visitType(Type t, Void ignored) { 4230 return t.getTag().ordinal(); 4231 } 4232 4233 @Override 4234 public Integer visitClassType(ClassType t, Void ignored) { 4235 int result = visit(t.getEnclosingType()); 4236 result *= 127; 4237 result += t.tsym.flatName().hashCode(); 4238 for (Type s : t.getTypeArguments()) { 4239 result *= 127; 4240 result += visit(s); 4241 } 4242 return result; 4243 } 4244 4245 @Override 4246 public Integer visitMethodType(MethodType t, Void ignored) { 4247 int h = METHOD.ordinal(); 4248 for (List<Type> thisargs = t.argtypes; 4249 thisargs.tail != null; 4250 thisargs = thisargs.tail) 4251 h = (h << 5) + visit(thisargs.head); 4252 return (h << 5) + visit(t.restype); 4253 } 4254 4255 @Override 4256 public Integer visitWildcardType(WildcardType t, Void ignored) { 4257 int result = t.kind.hashCode(); 4258 if (t.type != null) { 4259 result *= 127; 4260 result += visit(t.type); 4261 } 4262 return result; 4263 } 4264 4265 @Override 4266 public Integer visitArrayType(ArrayType t, Void ignored) { 4267 return visit(t.elemtype) + 12; 4268 } 4269 4270 @Override 4271 public Integer visitTypeVar(TypeVar t, Void ignored) { 4272 return System.identityHashCode(t); 4273 } 4274 4275 @Override 4276 public Integer visitUndetVar(UndetVar t, Void ignored) { 4277 return System.identityHashCode(t); 4278 } 4279 4280 @Override 4281 public Integer visitErrorType(ErrorType t, Void ignored) { 4282 return 0; 4283 } 4284 } 4285 // </editor-fold> 4286 4287 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable"> 4288 /** 4289 * Does t have a result that is a subtype of the result type of s, 4290 * suitable for covariant returns? It is assumed that both types 4291 * are (possibly polymorphic) method types. Monomorphic method 4292 * types are handled in the obvious way. Polymorphic method types 4293 * require renaming all type variables of one to corresponding 4294 * type variables in the other, where correspondence is by 4295 * position in the type parameter list. */ 4296 public boolean resultSubtype(Type t, Type s, Warner warner) { 4297 List<Type> tvars = t.getTypeArguments(); 4298 List<Type> svars = s.getTypeArguments(); 4299 Type tres = t.getReturnType(); 4300 Type sres = subst(s.getReturnType(), svars, tvars); 4301 return covariantReturnType(tres, sres, warner); 4302 } 4303 4304 /** 4305 * Return-Type-Substitutable. 4306 * @jls 8.4.5 Method Result 4307 */ 4308 public boolean returnTypeSubstitutable(Type r1, Type r2) { 4309 if (hasSameArgs(r1, r2)) 4310 return resultSubtype(r1, r2, noWarnings); 4311 else 4312 return covariantReturnType(r1.getReturnType(), 4313 erasure(r2.getReturnType()), 4314 noWarnings); 4315 } 4316 4317 public boolean returnTypeSubstitutable(Type r1, 4318 Type r2, Type r2res, 4319 Warner warner) { 4320 if (isSameType(r1.getReturnType(), r2res)) 4321 return true; 4322 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive()) 4323 return false; 4324 4325 if (hasSameArgs(r1, r2)) 4326 return covariantReturnType(r1.getReturnType(), r2res, warner); 4327 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner)) 4328 return true; 4329 if (!isSubtype(r1.getReturnType(), erasure(r2res))) 4330 return false; 4331 warner.warn(LintCategory.UNCHECKED); 4332 return true; 4333 } 4334 4335 /** 4336 * Is t an appropriate return type in an overrider for a 4337 * method that returns s? 4338 */ 4339 public boolean covariantReturnType(Type t, Type s, Warner warner) { 4340 return 4341 isSameType(t, s) || 4342 !t.isPrimitive() && 4343 !s.isPrimitive() && 4344 isAssignable(t, s, warner); 4345 } 4346 // </editor-fold> 4347 4348 // <editor-fold defaultstate="collapsed" desc="Box/unbox support"> 4349 /** 4350 * Return the class that boxes the given primitive. 4351 */ 4352 public ClassSymbol boxedClass(Type t) { 4353 return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]); 4354 } 4355 4356 /** 4357 * Return the boxed type if 't' is primitive, otherwise return 't' itself. 4358 */ 4359 public Type boxedTypeOrType(Type t) { 4360 return t.isPrimitive() ? 4361 boxedClass(t).type : 4362 t; 4363 } 4364 4365 /** 4366 * Return the primitive type corresponding to a boxed type. 4367 */ 4368 public Type unboxedType(Type t) { 4369 if (t.hasTag(ERROR)) 4370 return Type.noType; 4371 for (int i=0; i<syms.boxedName.length; i++) { 4372 Name box = syms.boxedName[i]; 4373 if (box != null && 4374 asSuper(t, syms.enterClass(syms.java_base, box)) != null) 4375 return syms.typeOfTag[i]; 4376 } 4377 return Type.noType; 4378 } 4379 4380 /** 4381 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself. 4382 */ 4383 public Type unboxedTypeOrType(Type t) { 4384 Type unboxedType = unboxedType(t); 4385 return unboxedType.hasTag(NONE) ? t : unboxedType; 4386 } 4387 // </editor-fold> 4388 4389 // <editor-fold defaultstate="collapsed" desc="Capture conversion"> 4390 /* 4391 * JLS 5.1.10 Capture Conversion: 4392 * 4393 * Let G name a generic type declaration with n formal type 4394 * parameters A1 ... An with corresponding bounds U1 ... Un. There 4395 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>, 4396 * where, for 1 <= i <= n: 4397 * 4398 * + If Ti is a wildcard type argument (4.5.1) of the form ? then 4399 * Si is a fresh type variable whose upper bound is 4400 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null 4401 * type. 4402 * 4403 * + If Ti is a wildcard type argument of the form ? extends Bi, 4404 * then Si is a fresh type variable whose upper bound is 4405 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is 4406 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is 4407 * a compile-time error if for any two classes (not interfaces) 4408 * Vi and Vj,Vi is not a subclass of Vj or vice versa. 4409 * 4410 * + If Ti is a wildcard type argument of the form ? super Bi, 4411 * then Si is a fresh type variable whose upper bound is 4412 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi. 4413 * 4414 * + Otherwise, Si = Ti. 4415 * 4416 * Capture conversion on any type other than a parameterized type 4417 * (4.5) acts as an identity conversion (5.1.1). Capture 4418 * conversions never require a special action at run time and 4419 * therefore never throw an exception at run time. 4420 * 4421 * Capture conversion is not applied recursively. 4422 */ 4423 /** 4424 * Capture conversion as specified by the JLS. 4425 */ 4426 4427 public List<Type> capture(List<Type> ts) { 4428 List<Type> buf = List.nil(); 4429 for (Type t : ts) { 4430 buf = buf.prepend(capture(t)); 4431 } 4432 return buf.reverse(); 4433 } 4434 4435 public Type capture(Type t) { 4436 if (!t.hasTag(CLASS)) { 4437 return t; 4438 } 4439 if (t.getEnclosingType() != Type.noType) { 4440 Type capturedEncl = capture(t.getEnclosingType()); 4441 if (capturedEncl != t.getEnclosingType()) { 4442 Type type1 = memberType(capturedEncl, t.tsym); 4443 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments()); 4444 } 4445 } 4446 ClassType cls = (ClassType)t; 4447 if (cls.isRaw() || !cls.isParameterized()) 4448 return cls; 4449 4450 ClassType G = (ClassType)cls.asElement().asType(); 4451 List<Type> A = G.getTypeArguments(); 4452 List<Type> T = cls.getTypeArguments(); 4453 List<Type> S = freshTypeVariables(T); 4454 4455 List<Type> currentA = A; 4456 List<Type> currentT = T; 4457 List<Type> currentS = S; 4458 boolean captured = false; 4459 while (!currentA.isEmpty() && 4460 !currentT.isEmpty() && 4461 !currentS.isEmpty()) { 4462 if (currentS.head != currentT.head) { 4463 captured = true; 4464 WildcardType Ti = (WildcardType)currentT.head; 4465 Type Ui = currentA.head.getUpperBound(); 4466 CapturedType Si = (CapturedType)currentS.head; 4467 if (Ui == null) 4468 Ui = syms.objectType; 4469 switch (Ti.kind) { 4470 case UNBOUND: 4471 Si.setUpperBound( subst(Ui, A, S) ); 4472 Si.lower = syms.botType; 4473 break; 4474 case EXTENDS: 4475 Si.setUpperBound( glb(Ti.getExtendsBound(), subst(Ui, A, S)) ); 4476 Si.lower = syms.botType; 4477 break; 4478 case SUPER: 4479 Si.setUpperBound( subst(Ui, A, S) ); 4480 Si.lower = Ti.getSuperBound(); 4481 break; 4482 } 4483 Type tmpBound = Si.getUpperBound().hasTag(UNDETVAR) ? ((UndetVar)Si.getUpperBound()).qtype : Si.getUpperBound(); 4484 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower; 4485 if (!Si.getUpperBound().hasTag(ERROR) && 4486 !Si.lower.hasTag(ERROR) && 4487 isSameType(tmpBound, tmpLower)) { 4488 currentS.head = Si.getUpperBound(); 4489 } 4490 } 4491 currentA = currentA.tail; 4492 currentT = currentT.tail; 4493 currentS = currentS.tail; 4494 } 4495 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty()) 4496 return erasure(t); // some "rare" type involved 4497 4498 if (captured) 4499 return new ClassType(cls.getEnclosingType(), S, cls.tsym, 4500 cls.getMetadata()); 4501 else 4502 return t; 4503 } 4504 // where 4505 public List<Type> freshTypeVariables(List<Type> types) { 4506 ListBuffer<Type> result = new ListBuffer<>(); 4507 for (Type t : types) { 4508 if (t.hasTag(WILDCARD)) { 4509 Type bound = ((WildcardType)t).getExtendsBound(); 4510 if (bound == null) 4511 bound = syms.objectType; 4512 result.append(new CapturedType(capturedName, 4513 syms.noSymbol, 4514 bound, 4515 syms.botType, 4516 (WildcardType)t)); 4517 } else { 4518 result.append(t); 4519 } 4520 } 4521 return result.toList(); 4522 } 4523 // </editor-fold> 4524 4525 // <editor-fold defaultstate="collapsed" desc="Internal utility methods"> 4526 private boolean sideCast(Type from, Type to, Warner warn) { 4527 // We are casting from type $from$ to type $to$, which are 4528 // non-final unrelated types. This method 4529 // tries to reject a cast by transferring type parameters 4530 // from $to$ to $from$ by common superinterfaces. 4531 boolean reverse = false; 4532 Type target = to; 4533 if ((to.tsym.flags() & INTERFACE) == 0) { 4534 Assert.check((from.tsym.flags() & INTERFACE) != 0); 4535 reverse = true; 4536 to = from; 4537 from = target; 4538 } 4539 List<Type> commonSupers = superClosure(to, erasure(from)); 4540 boolean giveWarning = commonSupers.isEmpty(); 4541 // The arguments to the supers could be unified here to 4542 // get a more accurate analysis 4543 while (commonSupers.nonEmpty()) { 4544 Type t1 = asSuper(from, commonSupers.head.tsym); 4545 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym); 4546 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments())) 4547 return false; 4548 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)); 4549 commonSupers = commonSupers.tail; 4550 } 4551 if (giveWarning && !isReifiable(reverse ? from : to)) 4552 warn.warn(LintCategory.UNCHECKED); 4553 return true; 4554 } 4555 4556 private boolean sideCastFinal(Type from, Type to, Warner warn) { 4557 // We are casting from type $from$ to type $to$, which are 4558 // unrelated types one of which is final and the other of 4559 // which is an interface. This method 4560 // tries to reject a cast by transferring type parameters 4561 // from the final class to the interface. 4562 boolean reverse = false; 4563 Type target = to; 4564 if ((to.tsym.flags() & INTERFACE) == 0) { 4565 Assert.check((from.tsym.flags() & INTERFACE) != 0); 4566 reverse = true; 4567 to = from; 4568 from = target; 4569 } 4570 Assert.check((from.tsym.flags() & FINAL) != 0); 4571 Type t1 = asSuper(from, to.tsym); 4572 if (t1 == null) return false; 4573 Type t2 = to; 4574 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments())) 4575 return false; 4576 if (!isReifiable(target) && 4577 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2))) 4578 warn.warn(LintCategory.UNCHECKED); 4579 return true; 4580 } 4581 4582 private boolean giveWarning(Type from, Type to) { 4583 List<Type> bounds = to.isCompound() ? 4584 directSupertypes(to) : List.of(to); 4585 for (Type b : bounds) { 4586 Type subFrom = asSub(from, b.tsym); 4587 if (b.isParameterized() && 4588 (!(isUnbounded(b) || 4589 isSubtype(from, b) || 4590 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) { 4591 return true; 4592 } 4593 } 4594 return false; 4595 } 4596 4597 private List<Type> superClosure(Type t, Type s) { 4598 List<Type> cl = List.nil(); 4599 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) { 4600 if (isSubtype(s, erasure(l.head))) { 4601 cl = insert(cl, l.head); 4602 } else { 4603 cl = union(cl, superClosure(l.head, s)); 4604 } 4605 } 4606 return cl; 4607 } 4608 4609 private boolean containsTypeEquivalent(Type t, Type s) { 4610 return isSameType(t, s) || // shortcut 4611 containsType(t, s) && containsType(s, t); 4612 } 4613 4614 // <editor-fold defaultstate="collapsed" desc="adapt"> 4615 /** 4616 * Adapt a type by computing a substitution which maps a source 4617 * type to a target type. 4618 * 4619 * @param source the source type 4620 * @param target the target type 4621 * @param from the type variables of the computed substitution 4622 * @param to the types of the computed substitution. 4623 */ 4624 public void adapt(Type source, 4625 Type target, 4626 ListBuffer<Type> from, 4627 ListBuffer<Type> to) throws AdaptFailure { 4628 new Adapter(from, to).adapt(source, target); 4629 } 4630 4631 class Adapter extends SimpleVisitor<Void, Type> { 4632 4633 ListBuffer<Type> from; 4634 ListBuffer<Type> to; 4635 Map<Symbol,Type> mapping; 4636 4637 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) { 4638 this.from = from; 4639 this.to = to; 4640 mapping = new HashMap<>(); 4641 } 4642 4643 public void adapt(Type source, Type target) throws AdaptFailure { 4644 visit(source, target); 4645 List<Type> fromList = from.toList(); 4646 List<Type> toList = to.toList(); 4647 while (!fromList.isEmpty()) { 4648 Type val = mapping.get(fromList.head.tsym); 4649 if (toList.head != val) 4650 toList.head = val; 4651 fromList = fromList.tail; 4652 toList = toList.tail; 4653 } 4654 } 4655 4656 @Override 4657 public Void visitClassType(ClassType source, Type target) throws AdaptFailure { 4658 if (target.hasTag(CLASS)) 4659 adaptRecursive(source.allparams(), target.allparams()); 4660 return null; 4661 } 4662 4663 @Override 4664 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure { 4665 if (target.hasTag(ARRAY)) 4666 adaptRecursive(elemtype(source), elemtype(target)); 4667 return null; 4668 } 4669 4670 @Override 4671 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure { 4672 if (source.isExtendsBound()) 4673 adaptRecursive(wildUpperBound(source), wildUpperBound(target)); 4674 else if (source.isSuperBound()) 4675 adaptRecursive(wildLowerBound(source), wildLowerBound(target)); 4676 return null; 4677 } 4678 4679 @Override 4680 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure { 4681 // Check to see if there is 4682 // already a mapping for $source$, in which case 4683 // the old mapping will be merged with the new 4684 Type val = mapping.get(source.tsym); 4685 if (val != null) { 4686 if (val.isSuperBound() && target.isSuperBound()) { 4687 val = isSubtype(wildLowerBound(val), wildLowerBound(target)) 4688 ? target : val; 4689 } else if (val.isExtendsBound() && target.isExtendsBound()) { 4690 val = isSubtype(wildUpperBound(val), wildUpperBound(target)) 4691 ? val : target; 4692 } else if (!isSameType(val, target)) { 4693 throw new AdaptFailure(); 4694 } 4695 } else { 4696 val = target; 4697 from.append(source); 4698 to.append(target); 4699 } 4700 mapping.put(source.tsym, val); 4701 return null; 4702 } 4703 4704 @Override 4705 public Void visitType(Type source, Type target) { 4706 return null; 4707 } 4708 4709 private Set<TypePair> cache = new HashSet<>(); 4710 4711 private void adaptRecursive(Type source, Type target) { 4712 TypePair pair = new TypePair(source, target); 4713 if (cache.add(pair)) { 4714 try { 4715 visit(source, target); 4716 } finally { 4717 cache.remove(pair); 4718 } 4719 } 4720 } 4721 4722 private void adaptRecursive(List<Type> source, List<Type> target) { 4723 if (source.length() == target.length()) { 4724 while (source.nonEmpty()) { 4725 adaptRecursive(source.head, target.head); 4726 source = source.tail; 4727 target = target.tail; 4728 } 4729 } 4730 } 4731 } 4732 4733 public static class AdaptFailure extends RuntimeException { 4734 static final long serialVersionUID = -7490231548272701566L; 4735 } 4736 4737 private void adaptSelf(Type t, 4738 ListBuffer<Type> from, 4739 ListBuffer<Type> to) { 4740 try { 4741 //if (t.tsym.type != t) 4742 adapt(t.tsym.type, t, from, to); 4743 } catch (AdaptFailure ex) { 4744 // Adapt should never fail calculating a mapping from 4745 // t.tsym.type to t as there can be no merge problem. 4746 throw new AssertionError(ex); 4747 } 4748 } 4749 // </editor-fold> 4750 4751 /** 4752 * Rewrite all type variables (universal quantifiers) in the given 4753 * type to wildcards (existential quantifiers). This is used to 4754 * determine if a cast is allowed. For example, if high is true 4755 * and {@code T <: Number}, then {@code List<T>} is rewritten to 4756 * {@code List<? extends Number>}. Since {@code List<Integer> <: 4757 * List<? extends Number>} a {@code List<T>} can be cast to {@code 4758 * List<Integer>} with a warning. 4759 * @param t a type 4760 * @param high if true return an upper bound; otherwise a lower 4761 * bound 4762 * @param rewriteTypeVars only rewrite captured wildcards if false; 4763 * otherwise rewrite all type variables 4764 * @return the type rewritten with wildcards (existential 4765 * quantifiers) only 4766 */ 4767 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) { 4768 return new Rewriter(high, rewriteTypeVars).visit(t); 4769 } 4770 4771 class Rewriter extends UnaryVisitor<Type> { 4772 4773 boolean high; 4774 boolean rewriteTypeVars; 4775 4776 Rewriter(boolean high, boolean rewriteTypeVars) { 4777 this.high = high; 4778 this.rewriteTypeVars = rewriteTypeVars; 4779 } 4780 4781 @Override 4782 public Type visitClassType(ClassType t, Void s) { 4783 ListBuffer<Type> rewritten = new ListBuffer<>(); 4784 boolean changed = false; 4785 for (Type arg : t.allparams()) { 4786 Type bound = visit(arg); 4787 if (arg != bound) { 4788 changed = true; 4789 } 4790 rewritten.append(bound); 4791 } 4792 if (changed) 4793 return subst(t.tsym.type, 4794 t.tsym.type.allparams(), 4795 rewritten.toList()); 4796 else 4797 return t; 4798 } 4799 4800 public Type visitType(Type t, Void s) { 4801 return t; 4802 } 4803 4804 @Override 4805 public Type visitCapturedType(CapturedType t, Void s) { 4806 Type w_bound = t.wildcard.type; 4807 Type bound = w_bound.contains(t) ? 4808 erasure(w_bound) : 4809 visit(w_bound); 4810 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind); 4811 } 4812 4813 @Override 4814 public Type visitTypeVar(TypeVar t, Void s) { 4815 if (rewriteTypeVars) { 4816 Type bound = t.getUpperBound().contains(t) ? 4817 erasure(t.getUpperBound()) : 4818 visit(t.getUpperBound()); 4819 return rewriteAsWildcardType(bound, t, EXTENDS); 4820 } else { 4821 return t; 4822 } 4823 } 4824 4825 @Override 4826 public Type visitWildcardType(WildcardType t, Void s) { 4827 Type bound2 = visit(t.type); 4828 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind); 4829 } 4830 4831 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) { 4832 switch (bk) { 4833 case EXTENDS: return high ? 4834 makeExtendsWildcard(B(bound), formal) : 4835 makeExtendsWildcard(syms.objectType, formal); 4836 case SUPER: return high ? 4837 makeSuperWildcard(syms.botType, formal) : 4838 makeSuperWildcard(B(bound), formal); 4839 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal); 4840 default: 4841 Assert.error("Invalid bound kind " + bk); 4842 return null; 4843 } 4844 } 4845 4846 Type B(Type t) { 4847 while (t.hasTag(WILDCARD)) { 4848 WildcardType w = (WildcardType)t; 4849 t = high ? 4850 w.getExtendsBound() : 4851 w.getSuperBound(); 4852 if (t == null) { 4853 t = high ? syms.objectType : syms.botType; 4854 } 4855 } 4856 return t; 4857 } 4858 } 4859 4860 4861 /** 4862 * Create a wildcard with the given upper (extends) bound; create 4863 * an unbounded wildcard if bound is Object. 4864 * 4865 * @param bound the upper bound 4866 * @param formal the formal type parameter that will be 4867 * substituted by the wildcard 4868 */ 4869 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) { 4870 if (bound == syms.objectType) { 4871 return new WildcardType(syms.objectType, 4872 BoundKind.UNBOUND, 4873 syms.boundClass, 4874 formal); 4875 } else { 4876 return new WildcardType(bound, 4877 BoundKind.EXTENDS, 4878 syms.boundClass, 4879 formal); 4880 } 4881 } 4882 4883 /** 4884 * Create a wildcard with the given lower (super) bound; create an 4885 * unbounded wildcard if bound is bottom (type of {@code null}). 4886 * 4887 * @param bound the lower bound 4888 * @param formal the formal type parameter that will be 4889 * substituted by the wildcard 4890 */ 4891 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) { 4892 if (bound.hasTag(BOT)) { 4893 return new WildcardType(syms.objectType, 4894 BoundKind.UNBOUND, 4895 syms.boundClass, 4896 formal); 4897 } else { 4898 return new WildcardType(bound, 4899 BoundKind.SUPER, 4900 syms.boundClass, 4901 formal); 4902 } 4903 } 4904 4905 /** 4906 * A wrapper for a type that allows use in sets. 4907 */ 4908 public static class UniqueType { 4909 public final Type type; 4910 final Types types; 4911 4912 public UniqueType(Type type, Types types) { 4913 this.type = type; 4914 this.types = types; 4915 } 4916 4917 public int hashCode() { 4918 return types.hashCode(type); 4919 } 4920 4921 public boolean equals(Object obj) { 4922 return (obj instanceof UniqueType uniqueType) && 4923 types.isSameType(type, uniqueType.type); 4924 } 4925 4926 public String toString() { 4927 return type.toString(); 4928 } 4929 4930 } 4931 // </editor-fold> 4932 4933 // <editor-fold defaultstate="collapsed" desc="Visitors"> 4934 /** 4935 * A default visitor for types. All visitor methods except 4936 * visitType are implemented by delegating to visitType. Concrete 4937 * subclasses must provide an implementation of visitType and can 4938 * override other methods as needed. 4939 * 4940 * @param <R> the return type of the operation implemented by this 4941 * visitor; use Void if no return type is needed. 4942 * @param <S> the type of the second argument (the first being the 4943 * type itself) of the operation implemented by this visitor; use 4944 * Void if a second argument is not needed. 4945 */ 4946 public abstract static class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> { 4947 public final R visit(Type t, S s) { return t.accept(this, s); } 4948 public R visitClassType(ClassType t, S s) { return visitType(t, s); } 4949 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); } 4950 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); } 4951 public R visitMethodType(MethodType t, S s) { return visitType(t, s); } 4952 public R visitPackageType(PackageType t, S s) { return visitType(t, s); } 4953 public R visitModuleType(ModuleType t, S s) { return visitType(t, s); } 4954 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); } 4955 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); } 4956 public R visitForAll(ForAll t, S s) { return visitType(t, s); } 4957 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); } 4958 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); } 4959 } 4960 4961 /** 4962 * A default visitor for symbols. All visitor methods except 4963 * visitSymbol are implemented by delegating to visitSymbol. Concrete 4964 * subclasses must provide an implementation of visitSymbol and can 4965 * override other methods as needed. 4966 * 4967 * @param <R> the return type of the operation implemented by this 4968 * visitor; use Void if no return type is needed. 4969 * @param <S> the type of the second argument (the first being the 4970 * symbol itself) of the operation implemented by this visitor; use 4971 * Void if a second argument is not needed. 4972 */ 4973 public abstract static class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> { 4974 public final R visit(Symbol s, S arg) { return s.accept(this, arg); } 4975 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); } 4976 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); } 4977 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); } 4978 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); } 4979 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); } 4980 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); } 4981 } 4982 4983 /** 4984 * A <em>simple</em> visitor for types. This visitor is simple as 4985 * captured wildcards, for-all types (generic methods), and 4986 * undetermined type variables (part of inference) are hidden. 4987 * Captured wildcards are hidden by treating them as type 4988 * variables and the rest are hidden by visiting their qtypes. 4989 * 4990 * @param <R> the return type of the operation implemented by this 4991 * visitor; use Void if no return type is needed. 4992 * @param <S> the type of the second argument (the first being the 4993 * type itself) of the operation implemented by this visitor; use 4994 * Void if a second argument is not needed. 4995 */ 4996 public abstract static class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> { 4997 @Override 4998 public R visitCapturedType(CapturedType t, S s) { 4999 return visitTypeVar(t, s); 5000 } 5001 @Override 5002 public R visitForAll(ForAll t, S s) { 5003 return visit(t.qtype, s); 5004 } 5005 @Override 5006 public R visitUndetVar(UndetVar t, S s) { 5007 return visit(t.qtype, s); 5008 } 5009 } 5010 5011 /** 5012 * A plain relation on types. That is a 2-ary function on the 5013 * form Type × Type → Boolean. 5014 * <!-- In plain text: Type x Type -> Boolean --> 5015 */ 5016 public abstract static class TypeRelation extends SimpleVisitor<Boolean,Type> {} 5017 5018 /** 5019 * A convenience visitor for implementing operations that only 5020 * require one argument (the type itself), that is, unary 5021 * operations. 5022 * 5023 * @param <R> the return type of the operation implemented by this 5024 * visitor; use Void if no return type is needed. 5025 */ 5026 public abstract static class UnaryVisitor<R> extends SimpleVisitor<R,Void> { 5027 public final R visit(Type t) { return t.accept(this, null); } 5028 } 5029 5030 /** 5031 * A visitor for implementing a mapping from types to types. The 5032 * default behavior of this class is to implement the identity 5033 * mapping (mapping a type to itself). This can be overridden in 5034 * subclasses. 5035 * 5036 * @param <S> the type of the second argument (the first being the 5037 * type itself) of this mapping; use Void if a second argument is 5038 * not needed. 5039 */ 5040 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> { 5041 public final Type visit(Type t) { return t.accept(this, null); } 5042 public Type visitType(Type t, S s) { return t; } 5043 } 5044 5045 /** 5046 * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}. 5047 * This class implements the functional interface {@code Function}, that allows it to be used 5048 * fluently in stream-like processing. 5049 */ 5050 public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> { 5051 @Override 5052 public Type apply(Type type) { return visit(type); } 5053 5054 List<Type> visit(List<Type> ts, S s) { 5055 return ts.map(t -> visit(t, s)); 5056 } 5057 5058 @Override 5059 public Type visitCapturedType(CapturedType t, S s) { 5060 return visitTypeVar(t, s); 5061 } 5062 } 5063 // </editor-fold> 5064 5065 5066 // <editor-fold defaultstate="collapsed" desc="Annotation support"> 5067 5068 public RetentionPolicy getRetention(Attribute.Compound a) { 5069 return getRetention(a.type.tsym); 5070 } 5071 5072 public RetentionPolicy getRetention(TypeSymbol sym) { 5073 RetentionPolicy vis = RetentionPolicy.CLASS; // the default 5074 Attribute.Compound c = sym.attribute(syms.retentionType.tsym); 5075 if (c != null) { 5076 Attribute value = c.member(names.value); 5077 if (value != null && value instanceof Attribute.Enum attributeEnum) { 5078 Name levelName = attributeEnum.value.name; 5079 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE; 5080 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS; 5081 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME; 5082 else ;// /* fail soft */ throw new AssertionError(levelName); 5083 } 5084 } 5085 return vis; 5086 } 5087 // </editor-fold> 5088 5089 // <editor-fold defaultstate="collapsed" desc="Signature Generation"> 5090 5091 public abstract static class SignatureGenerator { 5092 5093 public static class InvalidSignatureException extends RuntimeException { 5094 private static final long serialVersionUID = 0; 5095 5096 private final transient Type type; 5097 5098 InvalidSignatureException(Type type) { 5099 this.type = type; 5100 } 5101 5102 public Type type() { 5103 return type; 5104 } 5105 5106 @Override 5107 public Throwable fillInStackTrace() { 5108 // This is an internal exception; the stack trace is irrelevant. 5109 return this; 5110 } 5111 } 5112 5113 private final Types types; 5114 5115 protected abstract void append(char ch); 5116 protected abstract void append(byte[] ba); 5117 protected abstract void append(Name name); 5118 protected void classReference(ClassSymbol c) { /* by default: no-op */ } 5119 5120 protected SignatureGenerator(Types types) { 5121 this.types = types; 5122 } 5123 5124 protected void reportIllegalSignature(Type t) { 5125 throw new InvalidSignatureException(t); 5126 } 5127 5128 /** 5129 * Assemble signature of given type in string buffer. 5130 */ 5131 public void assembleSig(Type type) { 5132 switch (type.getTag()) { 5133 case BYTE: 5134 append('B'); 5135 break; 5136 case SHORT: 5137 append('S'); 5138 break; 5139 case CHAR: 5140 append('C'); 5141 break; 5142 case INT: 5143 append('I'); 5144 break; 5145 case LONG: 5146 append('J'); 5147 break; 5148 case FLOAT: 5149 append('F'); 5150 break; 5151 case DOUBLE: 5152 append('D'); 5153 break; 5154 case BOOLEAN: 5155 append('Z'); 5156 break; 5157 case VOID: 5158 append('V'); 5159 break; 5160 case CLASS: 5161 if (type.isCompound()) { 5162 reportIllegalSignature(type); 5163 } 5164 append('L'); 5165 assembleClassSig(type); 5166 append(';'); 5167 break; 5168 case ARRAY: 5169 ArrayType at = (ArrayType) type; 5170 append('['); 5171 assembleSig(at.elemtype); 5172 break; 5173 case METHOD: 5174 MethodType mt = (MethodType) type; 5175 append('('); 5176 assembleSig(mt.argtypes); 5177 append(')'); 5178 assembleSig(mt.restype); 5179 if (hasTypeVar(mt.thrown)) { 5180 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) { 5181 append('^'); 5182 assembleSig(l.head); 5183 } 5184 } 5185 break; 5186 case WILDCARD: { 5187 Type.WildcardType ta = (Type.WildcardType) type; 5188 switch (ta.kind) { 5189 case SUPER: 5190 append('-'); 5191 assembleSig(ta.type); 5192 break; 5193 case EXTENDS: 5194 append('+'); 5195 assembleSig(ta.type); 5196 break; 5197 case UNBOUND: 5198 append('*'); 5199 break; 5200 default: 5201 throw new AssertionError(ta.kind); 5202 } 5203 break; 5204 } 5205 case TYPEVAR: 5206 if (((TypeVar)type).isCaptured()) { 5207 reportIllegalSignature(type); 5208 } 5209 append('T'); 5210 append(type.tsym.name); 5211 append(';'); 5212 break; 5213 case FORALL: 5214 Type.ForAll ft = (Type.ForAll) type; 5215 assembleParamsSig(ft.tvars); 5216 assembleSig(ft.qtype); 5217 break; 5218 default: 5219 throw new AssertionError("typeSig " + type.getTag()); 5220 } 5221 } 5222 5223 public boolean hasTypeVar(List<Type> l) { 5224 while (l.nonEmpty()) { 5225 if (l.head.hasTag(TypeTag.TYPEVAR)) { 5226 return true; 5227 } 5228 l = l.tail; 5229 } 5230 return false; 5231 } 5232 5233 public void assembleClassSig(Type type) { 5234 ClassType ct = (ClassType) type; 5235 ClassSymbol c = (ClassSymbol) ct.tsym; 5236 classReference(c); 5237 Type outer = ct.getEnclosingType(); 5238 if (outer.allparams().nonEmpty()) { 5239 boolean rawOuter = 5240 c.owner.kind == MTH || // either a local class 5241 c.name == types.names.empty; // or anonymous 5242 assembleClassSig(rawOuter 5243 ? types.erasure(outer) 5244 : outer); 5245 append(rawOuter ? '$' : '.'); 5246 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname)); 5247 append(rawOuter 5248 ? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength()) 5249 : c.name); 5250 } else { 5251 append(externalize(c.flatname)); 5252 } 5253 if (ct.getTypeArguments().nonEmpty()) { 5254 append('<'); 5255 assembleSig(ct.getTypeArguments()); 5256 append('>'); 5257 } 5258 } 5259 5260 public void assembleParamsSig(List<Type> typarams) { 5261 append('<'); 5262 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) { 5263 Type.TypeVar tvar = (Type.TypeVar) ts.head; 5264 append(tvar.tsym.name); 5265 List<Type> bounds = types.getBounds(tvar); 5266 if ((bounds.head.tsym.flags() & INTERFACE) != 0) { 5267 append(':'); 5268 } 5269 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) { 5270 append(':'); 5271 assembleSig(l.head); 5272 } 5273 } 5274 append('>'); 5275 } 5276 5277 public void assembleSig(List<Type> types) { 5278 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) { 5279 assembleSig(ts.head); 5280 } 5281 } 5282 } 5283 5284 public Type constantType(LoadableConstant c) { 5285 switch (c.poolTag()) { 5286 case ClassFile.CONSTANT_Class: 5287 return syms.classType; 5288 case ClassFile.CONSTANT_String: 5289 return syms.stringType; 5290 case ClassFile.CONSTANT_Integer: 5291 return syms.intType; 5292 case ClassFile.CONSTANT_Float: 5293 return syms.floatType; 5294 case ClassFile.CONSTANT_Long: 5295 return syms.longType; 5296 case ClassFile.CONSTANT_Double: 5297 return syms.doubleType; 5298 case ClassFile.CONSTANT_MethodHandle: 5299 return syms.methodHandleType; 5300 case ClassFile.CONSTANT_MethodType: 5301 return syms.methodTypeType; 5302 case ClassFile.CONSTANT_Dynamic: 5303 return ((DynamicVarSymbol)c).type; 5304 default: 5305 throw new AssertionError("Not a loadable constant: " + c.poolTag()); 5306 } 5307 } 5308 // </editor-fold> 5309 5310 public void newRound() { 5311 descCache._map.clear(); 5312 isDerivedRawCache.clear(); 5313 implCache._map.clear(); 5314 membersCache._map.clear(); 5315 closureCache.clear(); 5316 } 5317 }