1 /* 2 * Copyright (c) 2003, 2023, 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.Annotations; 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 @SuppressWarnings("this-escape") 112 protected Types(Context context) { 113 context.put(typesKey, this); 114 syms = Symtab.instance(context); 115 names = Names.instance(context); 116 Source source = Source.instance(context); 117 chk = Check.instance(context); 118 enter = Enter.instance(context); 119 capturedName = names.fromString("<captured wildcard>"); 120 messages = JavacMessages.instance(context); 121 diags = JCDiagnostic.Factory.instance(context); 122 noWarnings = new Warner(null); 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 tMap.put(ti.tsym, ti); 1412 } 1413 for (Type si : interfaces(s)) { 1414 if (!tMap.containsKey(si.tsym)) 1415 return false; 1416 Type ti = tMap.remove(si.tsym); 1417 if (!visit(ti, si)) 1418 return false; 1419 } 1420 return tMap.isEmpty(); 1421 } 1422 return t.tsym == s.tsym 1423 && visit(t.getEnclosingType(), s.getEnclosingType()) 1424 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments()); 1425 } 1426 1427 @Override 1428 public Boolean visitArrayType(ArrayType t, Type s) { 1429 if (t == s) 1430 return true; 1431 1432 if (s.isPartial()) 1433 return visit(s, t); 1434 1435 return s.hasTag(ARRAY) 1436 && containsTypeEquivalent(t.elemtype, elemtype(s)); 1437 } 1438 1439 @Override 1440 public Boolean visitMethodType(MethodType t, Type s) { 1441 // isSameType for methods does not take thrown 1442 // exceptions into account! 1443 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType()); 1444 } 1445 1446 @Override 1447 public Boolean visitPackageType(PackageType t, Type s) { 1448 return t == s; 1449 } 1450 1451 @Override 1452 public Boolean visitForAll(ForAll t, Type s) { 1453 if (!s.hasTag(FORALL)) { 1454 return false; 1455 } 1456 1457 ForAll forAll = (ForAll)s; 1458 return hasSameBounds(t, forAll) 1459 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars)); 1460 } 1461 1462 @Override 1463 public Boolean visitUndetVar(UndetVar t, Type s) { 1464 if (s.hasTag(WILDCARD)) { 1465 // FIXME, this might be leftovers from before capture conversion 1466 return false; 1467 } 1468 1469 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) { 1470 return true; 1471 } 1472 1473 t.addBound(InferenceBound.EQ, s, Types.this); 1474 1475 return true; 1476 } 1477 1478 @Override 1479 public Boolean visitErrorType(ErrorType t, Type s) { 1480 return true; 1481 } 1482 }; 1483 1484 // </editor-fold> 1485 1486 // <editor-fold defaultstate="collapsed" desc="Contains Type"> 1487 public boolean containedBy(Type t, Type s) { 1488 switch (t.getTag()) { 1489 case UNDETVAR: 1490 if (s.hasTag(WILDCARD)) { 1491 UndetVar undetvar = (UndetVar)t; 1492 WildcardType wt = (WildcardType)s; 1493 switch(wt.kind) { 1494 case UNBOUND: 1495 break; 1496 case EXTENDS: { 1497 Type bound = wildUpperBound(s); 1498 undetvar.addBound(InferenceBound.UPPER, bound, this); 1499 break; 1500 } 1501 case SUPER: { 1502 Type bound = wildLowerBound(s); 1503 undetvar.addBound(InferenceBound.LOWER, bound, this); 1504 break; 1505 } 1506 } 1507 return true; 1508 } else { 1509 return isSameType(t, s); 1510 } 1511 case ERROR: 1512 return true; 1513 default: 1514 return containsType(s, t); 1515 } 1516 } 1517 1518 boolean containsType(List<Type> ts, List<Type> ss) { 1519 while (ts.nonEmpty() && ss.nonEmpty() 1520 && containsType(ts.head, ss.head)) { 1521 ts = ts.tail; 1522 ss = ss.tail; 1523 } 1524 return ts.isEmpty() && ss.isEmpty(); 1525 } 1526 1527 /** 1528 * Check if t contains s. 1529 * 1530 * <p>T contains S if: 1531 * 1532 * <p>{@code L(T) <: L(S) && U(S) <: U(T)} 1533 * 1534 * <p>This relation is only used by ClassType.isSubtype(), that 1535 * is, 1536 * 1537 * <p>{@code C<S> <: C<T> if T contains S.} 1538 * 1539 * <p>Because of F-bounds, this relation can lead to infinite 1540 * recursion. Thus we must somehow break that recursion. Notice 1541 * that containsType() is only called from ClassType.isSubtype(). 1542 * Since the arguments have already been checked against their 1543 * bounds, we know: 1544 * 1545 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)} 1546 * 1547 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)} 1548 * 1549 * @param t a type 1550 * @param s a type 1551 */ 1552 public boolean containsType(Type t, Type s) { 1553 return containsType.visit(t, s); 1554 } 1555 // where 1556 private TypeRelation containsType = new TypeRelation() { 1557 1558 public Boolean visitType(Type t, Type s) { 1559 if (s.isPartial()) 1560 return containedBy(s, t); 1561 else 1562 return isSameType(t, s); 1563 } 1564 1565 // void debugContainsType(WildcardType t, Type s) { 1566 // System.err.println(); 1567 // System.err.format(" does %s contain %s?%n", t, s); 1568 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n", 1569 // wildUpperBound(s), s, t, wildUpperBound(t), 1570 // t.isSuperBound() 1571 // || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t))); 1572 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n", 1573 // wildLowerBound(t), t, s, wildLowerBound(s), 1574 // t.isExtendsBound() 1575 // || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))); 1576 // System.err.println(); 1577 // } 1578 1579 @Override 1580 public Boolean visitWildcardType(WildcardType t, Type s) { 1581 if (s.isPartial()) 1582 return containedBy(s, t); 1583 else { 1584 // debugContainsType(t, s); 1585 return isSameWildcard(t, s) 1586 || isCaptureOf(s, t) 1587 || ((t.isExtendsBound() || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))) && 1588 (t.isSuperBound() || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t)))); 1589 } 1590 } 1591 1592 @Override 1593 public Boolean visitUndetVar(UndetVar t, Type s) { 1594 if (!s.hasTag(WILDCARD)) { 1595 return isSameType(t, s); 1596 } else { 1597 return false; 1598 } 1599 } 1600 1601 @Override 1602 public Boolean visitErrorType(ErrorType t, Type s) { 1603 return true; 1604 } 1605 }; 1606 1607 public boolean isCaptureOf(Type s, WildcardType t) { 1608 if (!s.hasTag(TYPEVAR) || !((TypeVar)s).isCaptured()) 1609 return false; 1610 return isSameWildcard(t, ((CapturedType)s).wildcard); 1611 } 1612 1613 public boolean isSameWildcard(WildcardType t, Type s) { 1614 if (!s.hasTag(WILDCARD)) 1615 return false; 1616 WildcardType w = (WildcardType)s; 1617 return w.kind == t.kind && w.type == t.type; 1618 } 1619 1620 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) { 1621 while (ts.nonEmpty() && ss.nonEmpty() 1622 && containsTypeEquivalent(ts.head, ss.head)) { 1623 ts = ts.tail; 1624 ss = ss.tail; 1625 } 1626 return ts.isEmpty() && ss.isEmpty(); 1627 } 1628 // </editor-fold> 1629 1630 // <editor-fold defaultstate="collapsed" desc="isCastable"> 1631 public boolean isCastable(Type t, Type s) { 1632 return isCastable(t, s, noWarnings); 1633 } 1634 1635 /** 1636 * Is t castable to s?<br> 1637 * s is assumed to be an erased type.<br> 1638 * (not defined for Method and ForAll types). 1639 */ 1640 public boolean isCastable(Type t, Type s, Warner warn) { 1641 // if same type 1642 if (t == s) 1643 return true; 1644 // if one of the types is primitive 1645 if (t.isPrimitive() != s.isPrimitive()) { 1646 t = skipTypeVars(t, false); 1647 return (isConvertible(t, s, warn) 1648 || (s.isPrimitive() && 1649 isSubtype(boxedClass(s).type, t))); 1650 } 1651 boolean result; 1652 if (warn != warnStack.head) { 1653 try { 1654 warnStack = warnStack.prepend(warn); 1655 checkUnsafeVarargsConversion(t, s, warn); 1656 result = isCastable.visit(t,s); 1657 } finally { 1658 warnStack = warnStack.tail; 1659 } 1660 } else { 1661 result = isCastable.visit(t,s); 1662 } 1663 if (result && t.hasTag(CLASS) && t.tsym.kind.matches(Kinds.KindSelector.TYP) 1664 && s.hasTag(CLASS) && s.tsym.kind.matches(Kinds.KindSelector.TYP) 1665 && (t.tsym.isSealed() || s.tsym.isSealed())) { 1666 return (t.isCompound() || s.isCompound()) ? 1667 true : 1668 !(new DisjointChecker().areDisjoint((ClassSymbol)t.tsym, (ClassSymbol)s.tsym)); 1669 } 1670 return result; 1671 } 1672 // where 1673 class DisjointChecker { 1674 Set<Pair<ClassSymbol, ClassSymbol>> pairsSeen = new HashSet<>(); 1675 private boolean areDisjoint(ClassSymbol ts, ClassSymbol ss) { 1676 Pair<ClassSymbol, ClassSymbol> newPair = new Pair<>(ts, ss); 1677 /* if we are seeing the same pair again then there is an issue with the sealed hierarchy 1678 * bail out, a detailed error will be reported downstream 1679 */ 1680 if (!pairsSeen.add(newPair)) 1681 return false; 1682 if (isSubtype(erasure(ts.type), erasure(ss.type))) { 1683 return false; 1684 } 1685 // if both are classes or both are interfaces, shortcut 1686 if (ts.isInterface() == ss.isInterface() && isSubtype(erasure(ss.type), erasure(ts.type))) { 1687 return false; 1688 } 1689 if (ts.isInterface() && !ss.isInterface()) { 1690 /* so ts is interface but ss is a class 1691 * an interface is disjoint from a class if the class is disjoint form the interface 1692 */ 1693 return areDisjoint(ss, ts); 1694 } 1695 // a final class that is not subtype of ss is disjoint 1696 if (!ts.isInterface() && ts.isFinal()) { 1697 return true; 1698 } 1699 // if at least one is sealed 1700 if (ts.isSealed() || ss.isSealed()) { 1701 // permitted subtypes have to be disjoint with the other symbol 1702 ClassSymbol sealedOne = ts.isSealed() ? ts : ss; 1703 ClassSymbol other = sealedOne == ts ? ss : ts; 1704 return sealedOne.getPermittedSubclasses().stream().allMatch(type -> areDisjoint((ClassSymbol)type.tsym, other)); 1705 } 1706 return false; 1707 } 1708 } 1709 1710 private TypeRelation isCastable = new TypeRelation() { 1711 1712 public Boolean visitType(Type t, Type s) { 1713 if (s.hasTag(ERROR) || t.hasTag(NONE)) 1714 return true; 1715 1716 switch (t.getTag()) { 1717 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT: 1718 case DOUBLE: 1719 return s.isNumeric(); 1720 case BOOLEAN: 1721 return s.hasTag(BOOLEAN); 1722 case VOID: 1723 return false; 1724 case BOT: 1725 return isSubtype(t, s); 1726 default: 1727 throw new AssertionError(); 1728 } 1729 } 1730 1731 @Override 1732 public Boolean visitWildcardType(WildcardType t, Type s) { 1733 return isCastable(wildUpperBound(t), s, warnStack.head); 1734 } 1735 1736 @Override 1737 public Boolean visitClassType(ClassType t, Type s) { 1738 if (s.hasTag(ERROR) || s.hasTag(BOT)) 1739 return true; 1740 1741 if (s.hasTag(TYPEVAR)) { 1742 if (isCastable(t, s.getUpperBound(), noWarnings)) { 1743 warnStack.head.warn(LintCategory.UNCHECKED); 1744 return true; 1745 } else { 1746 return false; 1747 } 1748 } 1749 1750 if (t.isCompound() || s.isCompound()) { 1751 return !t.isCompound() ? 1752 visitCompoundType((ClassType)s, t, true) : 1753 visitCompoundType(t, s, false); 1754 } 1755 1756 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) { 1757 boolean upcast; 1758 if ((upcast = isSubtype(erasure(t), erasure(s))) 1759 || isSubtype(erasure(s), erasure(t))) { 1760 if (!upcast && s.hasTag(ARRAY)) { 1761 if (!isReifiable(s)) 1762 warnStack.head.warn(LintCategory.UNCHECKED); 1763 return true; 1764 } else if (s.isRaw()) { 1765 return true; 1766 } else if (t.isRaw()) { 1767 if (!isUnbounded(s)) 1768 warnStack.head.warn(LintCategory.UNCHECKED); 1769 return true; 1770 } 1771 // Assume |a| <: |b| 1772 final Type a = upcast ? t : s; 1773 final Type b = upcast ? s : t; 1774 final boolean HIGH = true; 1775 final boolean LOW = false; 1776 final boolean DONT_REWRITE_TYPEVARS = false; 1777 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS); 1778 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS); 1779 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS); 1780 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS); 1781 Type lowSub = asSub(bLow, aLow.tsym); 1782 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym); 1783 if (highSub == null) { 1784 final boolean REWRITE_TYPEVARS = true; 1785 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS); 1786 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS); 1787 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS); 1788 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS); 1789 lowSub = asSub(bLow, aLow.tsym); 1790 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym); 1791 } 1792 if (highSub != null) { 1793 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) { 1794 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym); 1795 } 1796 if (!disjointTypes(aHigh.allparams(), highSub.allparams()) 1797 && !disjointTypes(aHigh.allparams(), lowSub.allparams()) 1798 && !disjointTypes(aLow.allparams(), highSub.allparams()) 1799 && !disjointTypes(aLow.allparams(), lowSub.allparams())) { 1800 if (upcast ? giveWarning(a, b) : 1801 giveWarning(b, a)) 1802 warnStack.head.warn(LintCategory.UNCHECKED); 1803 return true; 1804 } 1805 } 1806 if (isReifiable(s)) 1807 return isSubtypeUnchecked(a, b); 1808 else 1809 return isSubtypeUnchecked(a, b, warnStack.head); 1810 } 1811 1812 // Sidecast 1813 if (s.hasTag(CLASS)) { 1814 if ((s.tsym.flags() & INTERFACE) != 0) { 1815 return ((t.tsym.flags() & FINAL) == 0) 1816 ? sideCast(t, s, warnStack.head) 1817 : sideCastFinal(t, s, warnStack.head); 1818 } else if ((t.tsym.flags() & INTERFACE) != 0) { 1819 return ((s.tsym.flags() & FINAL) == 0) 1820 ? sideCast(t, s, warnStack.head) 1821 : sideCastFinal(t, s, warnStack.head); 1822 } else { 1823 // unrelated class types 1824 return false; 1825 } 1826 } 1827 } 1828 return false; 1829 } 1830 1831 boolean visitCompoundType(ClassType ct, Type s, boolean reverse) { 1832 Warner warn = noWarnings; 1833 for (Type c : directSupertypes(ct)) { 1834 warn.clear(); 1835 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn)) 1836 return false; 1837 } 1838 if (warn.hasLint(LintCategory.UNCHECKED)) 1839 warnStack.head.warn(LintCategory.UNCHECKED); 1840 return true; 1841 } 1842 1843 @Override 1844 public Boolean visitArrayType(ArrayType t, Type s) { 1845 switch (s.getTag()) { 1846 case ERROR: 1847 case BOT: 1848 return true; 1849 case TYPEVAR: 1850 if (isCastable(s, t, noWarnings)) { 1851 warnStack.head.warn(LintCategory.UNCHECKED); 1852 return true; 1853 } else { 1854 return false; 1855 } 1856 case CLASS: 1857 return isSubtype(t, s); 1858 case ARRAY: 1859 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) { 1860 return elemtype(t).hasTag(elemtype(s).getTag()); 1861 } else { 1862 return isCastable(elemtype(t), elemtype(s), warnStack.head); 1863 } 1864 default: 1865 return false; 1866 } 1867 } 1868 1869 @Override 1870 public Boolean visitTypeVar(TypeVar t, Type s) { 1871 switch (s.getTag()) { 1872 case ERROR: 1873 case BOT: 1874 return true; 1875 case TYPEVAR: 1876 if (isSubtype(t, s)) { 1877 return true; 1878 } else if (isCastable(t.getUpperBound(), s, noWarnings)) { 1879 warnStack.head.warn(LintCategory.UNCHECKED); 1880 return true; 1881 } else { 1882 return false; 1883 } 1884 default: 1885 return isCastable(t.getUpperBound(), s, warnStack.head); 1886 } 1887 } 1888 1889 @Override 1890 public Boolean visitErrorType(ErrorType t, Type s) { 1891 return true; 1892 } 1893 }; 1894 // </editor-fold> 1895 1896 // <editor-fold defaultstate="collapsed" desc="disjointTypes"> 1897 public boolean disjointTypes(List<Type> ts, List<Type> ss) { 1898 while (ts.tail != null && ss.tail != null) { 1899 if (disjointType(ts.head, ss.head)) return true; 1900 ts = ts.tail; 1901 ss = ss.tail; 1902 } 1903 return false; 1904 } 1905 1906 /** 1907 * Two types or wildcards are considered disjoint if it can be 1908 * proven that no type can be contained in both. It is 1909 * conservative in that it is allowed to say that two types are 1910 * not disjoint, even though they actually are. 1911 * 1912 * The type {@code C<X>} is castable to {@code C<Y>} exactly if 1913 * {@code X} and {@code Y} are not disjoint. 1914 */ 1915 public boolean disjointType(Type t, Type s) { 1916 return disjointType.visit(t, s); 1917 } 1918 // where 1919 private TypeRelation disjointType = new TypeRelation() { 1920 1921 private Set<TypePair> cache = new HashSet<>(); 1922 1923 @Override 1924 public Boolean visitType(Type t, Type s) { 1925 if (s.hasTag(WILDCARD)) 1926 return visit(s, t); 1927 else 1928 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t); 1929 } 1930 1931 private boolean isCastableRecursive(Type t, Type s) { 1932 TypePair pair = new TypePair(t, s); 1933 if (cache.add(pair)) { 1934 try { 1935 return Types.this.isCastable(t, s); 1936 } finally { 1937 cache.remove(pair); 1938 } 1939 } else { 1940 return true; 1941 } 1942 } 1943 1944 private boolean notSoftSubtypeRecursive(Type t, Type s) { 1945 TypePair pair = new TypePair(t, s); 1946 if (cache.add(pair)) { 1947 try { 1948 return Types.this.notSoftSubtype(t, s); 1949 } finally { 1950 cache.remove(pair); 1951 } 1952 } else { 1953 return false; 1954 } 1955 } 1956 1957 @Override 1958 public Boolean visitWildcardType(WildcardType t, Type s) { 1959 if (t.isUnbound()) 1960 return false; 1961 1962 if (!s.hasTag(WILDCARD)) { 1963 if (t.isExtendsBound()) 1964 return notSoftSubtypeRecursive(s, t.type); 1965 else 1966 return notSoftSubtypeRecursive(t.type, s); 1967 } 1968 1969 if (s.isUnbound()) 1970 return false; 1971 1972 if (t.isExtendsBound()) { 1973 if (s.isExtendsBound()) 1974 return !isCastableRecursive(t.type, wildUpperBound(s)); 1975 else if (s.isSuperBound()) 1976 return notSoftSubtypeRecursive(wildLowerBound(s), t.type); 1977 } else if (t.isSuperBound()) { 1978 if (s.isExtendsBound()) 1979 return notSoftSubtypeRecursive(t.type, wildUpperBound(s)); 1980 } 1981 return false; 1982 } 1983 }; 1984 // </editor-fold> 1985 1986 // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds"> 1987 public List<Type> cvarLowerBounds(List<Type> ts) { 1988 return ts.map(cvarLowerBoundMapping); 1989 } 1990 private final TypeMapping<Void> cvarLowerBoundMapping = new TypeMapping<Void>() { 1991 @Override 1992 public Type visitCapturedType(CapturedType t, Void _unused) { 1993 return cvarLowerBound(t); 1994 } 1995 }; 1996 // </editor-fold> 1997 1998 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype"> 1999 /** 2000 * This relation answers the question: is impossible that 2001 * something of type `t' can be a subtype of `s'? This is 2002 * different from the question "is `t' not a subtype of `s'?" 2003 * when type variables are involved: Integer is not a subtype of T 2004 * where {@code <T extends Number>} but it is not true that Integer cannot 2005 * possibly be a subtype of T. 2006 */ 2007 public boolean notSoftSubtype(Type t, Type s) { 2008 if (t == s) return false; 2009 if (t.hasTag(TYPEVAR)) { 2010 TypeVar tv = (TypeVar) t; 2011 return !isCastable(tv.getUpperBound(), 2012 relaxBound(s), 2013 noWarnings); 2014 } 2015 if (!s.hasTag(WILDCARD)) 2016 s = cvarUpperBound(s); 2017 2018 return !isSubtype(t, relaxBound(s)); 2019 } 2020 2021 private Type relaxBound(Type t) { 2022 return (t.hasTag(TYPEVAR)) ? 2023 rewriteQuantifiers(skipTypeVars(t, false), true, true) : 2024 t; 2025 } 2026 // </editor-fold> 2027 2028 // <editor-fold defaultstate="collapsed" desc="isReifiable"> 2029 public boolean isReifiable(Type t) { 2030 return isReifiable.visit(t); 2031 } 2032 // where 2033 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() { 2034 2035 public Boolean visitType(Type t, Void ignored) { 2036 return true; 2037 } 2038 2039 @Override 2040 public Boolean visitClassType(ClassType t, Void ignored) { 2041 if (t.isCompound()) 2042 return false; 2043 else { 2044 if (!t.isParameterized()) 2045 return true; 2046 2047 for (Type param : t.allparams()) { 2048 if (!param.isUnbound()) 2049 return false; 2050 } 2051 return true; 2052 } 2053 } 2054 2055 @Override 2056 public Boolean visitArrayType(ArrayType t, Void ignored) { 2057 return visit(t.elemtype); 2058 } 2059 2060 @Override 2061 public Boolean visitTypeVar(TypeVar t, Void ignored) { 2062 return false; 2063 } 2064 }; 2065 // </editor-fold> 2066 2067 // <editor-fold defaultstate="collapsed" desc="Array Utils"> 2068 public boolean isArray(Type t) { 2069 while (t.hasTag(WILDCARD)) 2070 t = wildUpperBound(t); 2071 return t.hasTag(ARRAY); 2072 } 2073 2074 /** 2075 * The element type of an array. 2076 */ 2077 public Type elemtype(Type t) { 2078 switch (t.getTag()) { 2079 case WILDCARD: 2080 return elemtype(wildUpperBound(t)); 2081 case ARRAY: 2082 return ((ArrayType)t).elemtype; 2083 case FORALL: 2084 return elemtype(((ForAll)t).qtype); 2085 case ERROR: 2086 return t; 2087 default: 2088 return null; 2089 } 2090 } 2091 2092 public Type elemtypeOrType(Type t) { 2093 Type elemtype = elemtype(t); 2094 return elemtype != null ? 2095 elemtype : 2096 t; 2097 } 2098 2099 /** 2100 * Mapping to take element type of an arraytype 2101 */ 2102 private TypeMapping<Void> elemTypeFun = new TypeMapping<Void>() { 2103 @Override 2104 public Type visitArrayType(ArrayType t, Void _unused) { 2105 return t.elemtype; 2106 } 2107 2108 @Override 2109 public Type visitTypeVar(TypeVar t, Void _unused) { 2110 return visit(skipTypeVars(t, false)); 2111 } 2112 }; 2113 2114 /** 2115 * The number of dimensions of an array type. 2116 */ 2117 public int dimensions(Type t) { 2118 int result = 0; 2119 while (t.hasTag(ARRAY)) { 2120 result++; 2121 t = elemtype(t); 2122 } 2123 return result; 2124 } 2125 2126 /** 2127 * Returns an ArrayType with the component type t 2128 * 2129 * @param t The component type of the ArrayType 2130 * @return the ArrayType for the given component 2131 */ 2132 public ArrayType makeArrayType(Type t) { 2133 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) { 2134 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString()); 2135 } 2136 return new ArrayType(t, syms.arrayClass); 2137 } 2138 // </editor-fold> 2139 2140 // <editor-fold defaultstate="collapsed" desc="asSuper"> 2141 /** 2142 * Return the (most specific) base type of t that starts with the 2143 * given symbol. If none exists, return null. 2144 * 2145 * Caveat Emptor: Since javac represents the class of all arrays with a singleton 2146 * symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant, 2147 * this method could yield surprising answers when invoked on arrays. For example when 2148 * invoked with t being byte [] and sym being t.sym itself, asSuper would answer null. 2149 * 2150 * @param t a type 2151 * @param sym a symbol 2152 */ 2153 public Type asSuper(Type t, Symbol sym) { 2154 /* Some examples: 2155 * 2156 * (Enum<E>, Comparable) => Comparable<E> 2157 * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind> 2158 * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree 2159 * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) => 2160 * Iterable<capture#160 of ? extends c.s.s.d.DocTree> 2161 */ 2162 if (sym.type == syms.objectType) { //optimization 2163 return syms.objectType; 2164 } 2165 return asSuper.visit(t, sym); 2166 } 2167 // where 2168 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() { 2169 2170 private Set<Symbol> seenTypes = new HashSet<>(); 2171 2172 public Type visitType(Type t, Symbol sym) { 2173 return null; 2174 } 2175 2176 @Override 2177 public Type visitClassType(ClassType t, Symbol sym) { 2178 if (t.tsym == sym) 2179 return t; 2180 2181 Symbol c = t.tsym; 2182 if (!seenTypes.add(c)) { 2183 return null; 2184 } 2185 try { 2186 Type st = supertype(t); 2187 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) { 2188 Type x = asSuper(st, sym); 2189 if (x != null) 2190 return x; 2191 } 2192 if ((sym.flags() & INTERFACE) != 0) { 2193 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) { 2194 if (!l.head.hasTag(ERROR)) { 2195 Type x = asSuper(l.head, sym); 2196 if (x != null) 2197 return x; 2198 } 2199 } 2200 } 2201 return null; 2202 } finally { 2203 seenTypes.remove(c); 2204 } 2205 } 2206 2207 @Override 2208 public Type visitArrayType(ArrayType t, Symbol sym) { 2209 return isSubtype(t, sym.type) ? sym.type : null; 2210 } 2211 2212 @Override 2213 public Type visitTypeVar(TypeVar t, Symbol sym) { 2214 if (t.tsym == sym) 2215 return t; 2216 else 2217 return asSuper(t.getUpperBound(), sym); 2218 } 2219 2220 @Override 2221 public Type visitErrorType(ErrorType t, Symbol sym) { 2222 return t; 2223 } 2224 }; 2225 2226 /** 2227 * Return the base type of t or any of its outer types that starts 2228 * with the given symbol. If none exists, return null. 2229 * 2230 * @param t a type 2231 * @param sym a symbol 2232 */ 2233 public Type asOuterSuper(Type t, Symbol sym) { 2234 switch (t.getTag()) { 2235 case CLASS: 2236 do { 2237 Type s = asSuper(t, sym); 2238 if (s != null) return s; 2239 t = t.getEnclosingType(); 2240 } while (t.hasTag(CLASS)); 2241 return null; 2242 case ARRAY: 2243 return isSubtype(t, sym.type) ? sym.type : null; 2244 case TYPEVAR: 2245 return asSuper(t, sym); 2246 case ERROR: 2247 return t; 2248 default: 2249 return null; 2250 } 2251 } 2252 2253 /** 2254 * Return the base type of t or any of its enclosing types that 2255 * starts with the given symbol. If none exists, return null. 2256 * 2257 * @param t a type 2258 * @param sym a symbol 2259 */ 2260 public Type asEnclosingSuper(Type t, Symbol sym) { 2261 switch (t.getTag()) { 2262 case CLASS: 2263 do { 2264 Type s = asSuper(t, sym); 2265 if (s != null) return s; 2266 Type outer = t.getEnclosingType(); 2267 t = (outer.hasTag(CLASS)) ? outer : 2268 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type : 2269 Type.noType; 2270 } while (t.hasTag(CLASS)); 2271 return null; 2272 case ARRAY: 2273 return isSubtype(t, sym.type) ? sym.type : null; 2274 case TYPEVAR: 2275 return asSuper(t, sym); 2276 case ERROR: 2277 return t; 2278 default: 2279 return null; 2280 } 2281 } 2282 // </editor-fold> 2283 2284 // <editor-fold defaultstate="collapsed" desc="memberType"> 2285 /** 2286 * The type of given symbol, seen as a member of t. 2287 * 2288 * @param t a type 2289 * @param sym a symbol 2290 */ 2291 public Type memberType(Type t, Symbol sym) { 2292 return (sym.flags() & STATIC) != 0 2293 ? sym.type 2294 : memberType.visit(t, sym); 2295 } 2296 // where 2297 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() { 2298 2299 public Type visitType(Type t, Symbol sym) { 2300 return sym.type; 2301 } 2302 2303 @Override 2304 public Type visitWildcardType(WildcardType t, Symbol sym) { 2305 return memberType(wildUpperBound(t), sym); 2306 } 2307 2308 @Override 2309 public Type visitClassType(ClassType t, Symbol sym) { 2310 Symbol owner = sym.owner; 2311 long flags = sym.flags(); 2312 if (((flags & STATIC) == 0) && owner.type.isParameterized()) { 2313 Type base = asOuterSuper(t, owner); 2314 //if t is an intersection type T = CT & I1 & I2 ... & In 2315 //its supertypes CT, I1, ... In might contain wildcards 2316 //so we need to go through capture conversion 2317 base = t.isCompound() ? capture(base) : base; 2318 if (base != null) { 2319 List<Type> ownerParams = owner.type.allparams(); 2320 List<Type> baseParams = base.allparams(); 2321 if (ownerParams.nonEmpty()) { 2322 if (baseParams.isEmpty()) { 2323 // then base is a raw type 2324 return erasure(sym.type); 2325 } else { 2326 return subst(sym.type, ownerParams, baseParams); 2327 } 2328 } 2329 } 2330 } 2331 return sym.type; 2332 } 2333 2334 @Override 2335 public Type visitTypeVar(TypeVar t, Symbol sym) { 2336 return memberType(t.getUpperBound(), sym); 2337 } 2338 2339 @Override 2340 public Type visitErrorType(ErrorType t, Symbol sym) { 2341 return t; 2342 } 2343 }; 2344 // </editor-fold> 2345 2346 // <editor-fold defaultstate="collapsed" desc="isAssignable"> 2347 public boolean isAssignable(Type t, Type s) { 2348 return isAssignable(t, s, noWarnings); 2349 } 2350 2351 /** 2352 * Is t assignable to s?<br> 2353 * Equivalent to subtype except for constant values and raw 2354 * types.<br> 2355 * (not defined for Method and ForAll types) 2356 */ 2357 public boolean isAssignable(Type t, Type s, Warner warn) { 2358 if (t.hasTag(ERROR)) 2359 return true; 2360 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) { 2361 int value = ((Number)t.constValue()).intValue(); 2362 switch (s.getTag()) { 2363 case BYTE: 2364 case CHAR: 2365 case SHORT: 2366 case INT: 2367 if (s.getTag().checkRange(value)) 2368 return true; 2369 break; 2370 case CLASS: 2371 switch (unboxedType(s).getTag()) { 2372 case BYTE: 2373 case CHAR: 2374 case SHORT: 2375 return isAssignable(t, unboxedType(s), warn); 2376 } 2377 break; 2378 } 2379 } 2380 return isConvertible(t, s, warn); 2381 } 2382 // </editor-fold> 2383 2384 // <editor-fold defaultstate="collapsed" desc="erasure"> 2385 /** 2386 * The erasure of t {@code |t|} -- the type that results when all 2387 * type parameters in t are deleted. 2388 */ 2389 public Type erasure(Type t) { 2390 return eraseNotNeeded(t) ? t : erasure(t, false); 2391 } 2392 //where 2393 private boolean eraseNotNeeded(Type t) { 2394 // We don't want to erase primitive types and String type as that 2395 // operation is idempotent. Also, erasing these could result in loss 2396 // of information such as constant values attached to such types. 2397 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym); 2398 } 2399 2400 private Type erasure(Type t, boolean recurse) { 2401 if (t.isPrimitive()) { 2402 return t; /* fast special case */ 2403 } else { 2404 Type out = erasure.visit(t, recurse); 2405 return out; 2406 } 2407 } 2408 // where 2409 private TypeMapping<Boolean> erasure = new StructuralTypeMapping<Boolean>() { 2410 @SuppressWarnings("fallthrough") 2411 private Type combineMetadata(final Type s, 2412 final Type t) { 2413 if (t.getMetadata().nonEmpty()) { 2414 switch (s.getTag()) { 2415 case CLASS: 2416 if (s instanceof UnionClassType || 2417 s instanceof IntersectionClassType) { 2418 return s; 2419 } 2420 //fall-through 2421 case BYTE, CHAR, SHORT, LONG, FLOAT, INT, DOUBLE, BOOLEAN, 2422 ARRAY, MODULE, TYPEVAR, WILDCARD, BOT: 2423 return s.dropMetadata(Annotations.class); 2424 case VOID, METHOD, PACKAGE, FORALL, DEFERRED, 2425 NONE, ERROR, UNKNOWN, UNDETVAR, UNINITIALIZED_THIS, 2426 UNINITIALIZED_OBJECT: 2427 return s; 2428 default: 2429 throw new AssertionError(s.getTag().name()); 2430 } 2431 } else { 2432 return s; 2433 } 2434 } 2435 2436 public Type visitType(Type t, Boolean recurse) { 2437 if (t.isPrimitive()) 2438 return t; /*fast special case*/ 2439 else { 2440 //other cases already handled 2441 return combineMetadata(t, t); 2442 } 2443 } 2444 2445 @Override 2446 public Type visitWildcardType(WildcardType t, Boolean recurse) { 2447 Type erased = erasure(wildUpperBound(t), recurse); 2448 return combineMetadata(erased, t); 2449 } 2450 2451 @Override 2452 public Type visitClassType(ClassType t, Boolean recurse) { 2453 Type erased = t.tsym.erasure(Types.this); 2454 if (recurse) { 2455 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym, 2456 t.dropMetadata(Annotations.class).getMetadata()); 2457 return erased; 2458 } else { 2459 return combineMetadata(erased, t); 2460 } 2461 } 2462 2463 @Override 2464 public Type visitTypeVar(TypeVar t, Boolean recurse) { 2465 Type erased = erasure(t.getUpperBound(), recurse); 2466 return combineMetadata(erased, t); 2467 } 2468 }; 2469 2470 public List<Type> erasure(List<Type> ts) { 2471 return erasure.visit(ts, false); 2472 } 2473 2474 public Type erasureRecursive(Type t) { 2475 return erasure(t, true); 2476 } 2477 2478 public List<Type> erasureRecursive(List<Type> ts) { 2479 return erasure.visit(ts, true); 2480 } 2481 // </editor-fold> 2482 2483 // <editor-fold defaultstate="collapsed" desc="makeIntersectionType"> 2484 /** 2485 * Make an intersection type from non-empty list of types. The list should be ordered according to 2486 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion. 2487 * Hence, this version of makeIntersectionType may not be called during a classfile read. 2488 * 2489 * @param bounds the types from which the intersection type is formed 2490 */ 2491 public IntersectionClassType makeIntersectionType(List<Type> bounds) { 2492 return makeIntersectionType(bounds, bounds.head.tsym.isInterface()); 2493 } 2494 2495 /** 2496 * Make an intersection type from non-empty list of types. The list should be ordered according to 2497 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as 2498 * an extra parameter indicates as to whether all bounds are interfaces - in which case the 2499 * supertype is implicitly assumed to be 'Object'. 2500 * 2501 * @param bounds the types from which the intersection type is formed 2502 * @param allInterfaces are all bounds interface types? 2503 */ 2504 public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) { 2505 Assert.check(bounds.nonEmpty()); 2506 Type firstExplicitBound = bounds.head; 2507 if (allInterfaces) { 2508 bounds = bounds.prepend(syms.objectType); 2509 } 2510 ClassSymbol bc = 2511 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC, 2512 Type.moreInfo 2513 ? names.fromString(bounds.toString()) 2514 : names.empty, 2515 null, 2516 syms.noSymbol); 2517 IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces); 2518 bc.type = intersectionType; 2519 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ? 2520 syms.objectType : // error condition, recover 2521 erasure(firstExplicitBound); 2522 bc.members_field = WriteableScope.create(bc); 2523 return intersectionType; 2524 } 2525 // </editor-fold> 2526 2527 // <editor-fold defaultstate="collapsed" desc="supertype"> 2528 public Type supertype(Type t) { 2529 return supertype.visit(t); 2530 } 2531 // where 2532 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() { 2533 2534 public Type visitType(Type t, Void ignored) { 2535 // A note on wildcards: there is no good way to 2536 // determine a supertype for a lower-bounded wildcard. 2537 return Type.noType; 2538 } 2539 2540 @Override 2541 public Type visitClassType(ClassType t, Void ignored) { 2542 if (t.supertype_field == null) { 2543 Type supertype = ((ClassSymbol)t.tsym).getSuperclass(); 2544 // An interface has no superclass; its supertype is Object. 2545 if (t.isInterface()) 2546 supertype = ((ClassType)t.tsym.type).supertype_field; 2547 if (t.supertype_field == null) { 2548 List<Type> actuals = classBound(t).allparams(); 2549 List<Type> formals = t.tsym.type.allparams(); 2550 if (t.hasErasedSupertypes()) { 2551 t.supertype_field = erasureRecursive(supertype); 2552 } else if (formals.nonEmpty()) { 2553 t.supertype_field = subst(supertype, formals, actuals); 2554 } 2555 else { 2556 t.supertype_field = supertype; 2557 } 2558 } 2559 } 2560 return t.supertype_field; 2561 } 2562 2563 /** 2564 * The supertype is always a class type. If the type 2565 * variable's bounds start with a class type, this is also 2566 * the supertype. Otherwise, the supertype is 2567 * java.lang.Object. 2568 */ 2569 @Override 2570 public Type visitTypeVar(TypeVar t, Void ignored) { 2571 if (t.getUpperBound().hasTag(TYPEVAR) || 2572 (!t.getUpperBound().isCompound() && !t.getUpperBound().isInterface())) { 2573 return t.getUpperBound(); 2574 } else { 2575 return supertype(t.getUpperBound()); 2576 } 2577 } 2578 2579 @Override 2580 public Type visitArrayType(ArrayType t, Void ignored) { 2581 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType)) 2582 return arraySuperType(); 2583 else 2584 return new ArrayType(supertype(t.elemtype), t.tsym); 2585 } 2586 2587 @Override 2588 public Type visitErrorType(ErrorType t, Void ignored) { 2589 return Type.noType; 2590 } 2591 }; 2592 // </editor-fold> 2593 2594 // <editor-fold defaultstate="collapsed" desc="interfaces"> 2595 /** 2596 * Return the interfaces implemented by this class. 2597 */ 2598 public List<Type> interfaces(Type t) { 2599 return interfaces.visit(t); 2600 } 2601 // where 2602 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() { 2603 2604 public List<Type> visitType(Type t, Void ignored) { 2605 return List.nil(); 2606 } 2607 2608 @Override 2609 public List<Type> visitClassType(ClassType t, Void ignored) { 2610 if (t.interfaces_field == null) { 2611 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces(); 2612 if (t.interfaces_field == null) { 2613 // If t.interfaces_field is null, then t must 2614 // be a parameterized type (not to be confused 2615 // with a generic type declaration). 2616 // Terminology: 2617 // Parameterized type: List<String> 2618 // Generic type declaration: class List<E> { ... } 2619 // So t corresponds to List<String> and 2620 // t.tsym.type corresponds to List<E>. 2621 // The reason t must be parameterized type is 2622 // that completion will happen as a side 2623 // effect of calling 2624 // ClassSymbol.getInterfaces. Since 2625 // t.interfaces_field is null after 2626 // completion, we can assume that t is not the 2627 // type of a class/interface declaration. 2628 Assert.check(t != t.tsym.type, t); 2629 List<Type> actuals = t.allparams(); 2630 List<Type> formals = t.tsym.type.allparams(); 2631 if (t.hasErasedSupertypes()) { 2632 t.interfaces_field = erasureRecursive(interfaces); 2633 } else if (formals.nonEmpty()) { 2634 t.interfaces_field = subst(interfaces, formals, actuals); 2635 } 2636 else { 2637 t.interfaces_field = interfaces; 2638 } 2639 } 2640 } 2641 return t.interfaces_field; 2642 } 2643 2644 @Override 2645 public List<Type> visitTypeVar(TypeVar t, Void ignored) { 2646 if (t.getUpperBound().isCompound()) 2647 return interfaces(t.getUpperBound()); 2648 2649 if (t.getUpperBound().isInterface()) 2650 return List.of(t.getUpperBound()); 2651 2652 return List.nil(); 2653 } 2654 }; 2655 2656 public List<Type> directSupertypes(Type t) { 2657 return directSupertypes.visit(t); 2658 } 2659 // where 2660 private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() { 2661 2662 public List<Type> visitType(final Type type, final Void ignored) { 2663 if (!type.isIntersection()) { 2664 final Type sup = supertype(type); 2665 return (sup == Type.noType || sup == type || sup == null) 2666 ? interfaces(type) 2667 : interfaces(type).prepend(sup); 2668 } else { 2669 return ((IntersectionClassType)type).getExplicitComponents(); 2670 } 2671 } 2672 }; 2673 2674 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) { 2675 for (Type i2 : interfaces(origin.type)) { 2676 if (isym == i2.tsym) return true; 2677 } 2678 return false; 2679 } 2680 // </editor-fold> 2681 2682 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw"> 2683 Map<Type,Boolean> isDerivedRawCache = new HashMap<>(); 2684 2685 public boolean isDerivedRaw(Type t) { 2686 Boolean result = isDerivedRawCache.get(t); 2687 if (result == null) { 2688 result = isDerivedRawInternal(t); 2689 isDerivedRawCache.put(t, result); 2690 } 2691 return result; 2692 } 2693 2694 public boolean isDerivedRawInternal(Type t) { 2695 if (t.isErroneous()) 2696 return false; 2697 return 2698 t.isRaw() || 2699 supertype(t) != Type.noType && isDerivedRaw(supertype(t)) || 2700 isDerivedRaw(interfaces(t)); 2701 } 2702 2703 public boolean isDerivedRaw(List<Type> ts) { 2704 List<Type> l = ts; 2705 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail; 2706 return l.nonEmpty(); 2707 } 2708 // </editor-fold> 2709 2710 // <editor-fold defaultstate="collapsed" desc="setBounds"> 2711 /** 2712 * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly, 2713 * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise 2714 * the supertype is simply left null (in this case, the supertype is assumed to be the head of 2715 * the bound list passed as second argument). Note that this check might cause a symbol completion. 2716 * Hence, this version of setBounds may not be called during a classfile read. 2717 * 2718 * @param t a type variable 2719 * @param bounds the bounds, must be nonempty 2720 */ 2721 public void setBounds(TypeVar t, List<Type> bounds) { 2722 setBounds(t, bounds, bounds.head.tsym.isInterface()); 2723 } 2724 2725 /** 2726 * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds. 2727 * This does not cause symbol completion as an extra parameter indicates as to whether all bounds 2728 * are interfaces - in which case the supertype is implicitly assumed to be 'Object'. 2729 * 2730 * @param t a type variable 2731 * @param bounds the bounds, must be nonempty 2732 * @param allInterfaces are all bounds interface types? 2733 */ 2734 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) { 2735 t.setUpperBound( bounds.tail.isEmpty() ? 2736 bounds.head : 2737 makeIntersectionType(bounds, allInterfaces) ); 2738 t.rank_field = -1; 2739 } 2740 // </editor-fold> 2741 2742 // <editor-fold defaultstate="collapsed" desc="getBounds"> 2743 /** 2744 * Return list of bounds of the given type variable. 2745 */ 2746 public List<Type> getBounds(TypeVar t) { 2747 if (t.getUpperBound().hasTag(NONE)) 2748 return List.nil(); 2749 else if (t.getUpperBound().isErroneous() || !t.getUpperBound().isCompound()) 2750 return List.of(t.getUpperBound()); 2751 else if ((erasure(t).tsym.flags() & INTERFACE) == 0) 2752 return interfaces(t).prepend(supertype(t)); 2753 else 2754 // No superclass was given in bounds. 2755 // In this case, supertype is Object, erasure is first interface. 2756 return interfaces(t); 2757 } 2758 // </editor-fold> 2759 2760 // <editor-fold defaultstate="collapsed" desc="classBound"> 2761 /** 2762 * If the given type is a (possibly selected) type variable, 2763 * return the bounding class of this type, otherwise return the 2764 * type itself. 2765 */ 2766 public Type classBound(Type t) { 2767 return classBound.visit(t); 2768 } 2769 // where 2770 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() { 2771 2772 public Type visitType(Type t, Void ignored) { 2773 return t; 2774 } 2775 2776 @Override 2777 public Type visitClassType(ClassType t, Void ignored) { 2778 Type outer1 = classBound(t.getEnclosingType()); 2779 if (outer1 != t.getEnclosingType()) 2780 return new ClassType(outer1, t.getTypeArguments(), t.tsym, 2781 t.getMetadata()); 2782 else 2783 return t; 2784 } 2785 2786 @Override 2787 public Type visitTypeVar(TypeVar t, Void ignored) { 2788 return classBound(supertype(t)); 2789 } 2790 2791 @Override 2792 public Type visitErrorType(ErrorType t, Void ignored) { 2793 return t; 2794 } 2795 }; 2796 // </editor-fold> 2797 2798 // <editor-fold defaultstate="collapsed" desc="subsignature / override equivalence"> 2799 /** 2800 * Returns true iff the first signature is a <em>subsignature</em> 2801 * of the other. This is <b>not</b> an equivalence 2802 * relation. 2803 * 2804 * @jls 8.4.2 Method Signature 2805 * @see #overrideEquivalent(Type t, Type s) 2806 * @param t first signature (possibly raw). 2807 * @param s second signature (could be subjected to erasure). 2808 * @return true if t is a subsignature of s. 2809 */ 2810 public boolean isSubSignature(Type t, Type s) { 2811 return hasSameArgs(t, s, true) || hasSameArgs(t, erasure(s), true); 2812 } 2813 2814 /** 2815 * Returns true iff these signatures are related by <em>override 2816 * equivalence</em>. This is the natural extension of 2817 * isSubSignature to an equivalence relation. 2818 * 2819 * @jls 8.4.2 Method Signature 2820 * @see #isSubSignature(Type t, Type s) 2821 * @param t a signature (possible raw, could be subjected to 2822 * erasure). 2823 * @param s a signature (possible raw, could be subjected to 2824 * erasure). 2825 * @return true if either argument is a subsignature of the other. 2826 */ 2827 public boolean overrideEquivalent(Type t, Type s) { 2828 return hasSameArgs(t, s) || 2829 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s); 2830 } 2831 2832 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) { 2833 for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) { 2834 if (msym.overrides(sym, origin, Types.this, true)) { 2835 return true; 2836 } 2837 } 2838 return false; 2839 } 2840 2841 /** 2842 * This enum defines the strategy for implementing most specific return type check 2843 * during the most specific and functional interface checks. 2844 */ 2845 public enum MostSpecificReturnCheck { 2846 /** 2847 * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling 2848 * method type variables (if either method is generic) and (ii) subtyping should be replaced 2849 * by type-equivalence for primitives. This is essentially an inlined version of 2850 * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been 2851 * replaced with a strict subtyping check. 2852 */ 2853 BASIC() { 2854 @Override 2855 public boolean test(Type mt1, Type mt2, Types types) { 2856 List<Type> tvars = mt1.getTypeArguments(); 2857 List<Type> svars = mt2.getTypeArguments(); 2858 Type t = mt1.getReturnType(); 2859 Type s = types.subst(mt2.getReturnType(), svars, tvars); 2860 return types.isSameType(t, s) || 2861 !t.isPrimitive() && 2862 !s.isPrimitive() && 2863 types.isSubtype(t, s); 2864 } 2865 }, 2866 /** 2867 * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2. 2868 */ 2869 RTS() { 2870 @Override 2871 public boolean test(Type mt1, Type mt2, Types types) { 2872 return types.returnTypeSubstitutable(mt1, mt2); 2873 } 2874 }; 2875 2876 public abstract boolean test(Type mt1, Type mt2, Types types); 2877 } 2878 2879 /** 2880 * Merge multiple abstract methods. The preferred method is a method that is a subsignature 2881 * of all the other signatures and whose return type is more specific {@link MostSpecificReturnCheck}. 2882 * The resulting preferred method has a throws clause that is the intersection of the merged 2883 * methods' clauses. 2884 */ 2885 public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) { 2886 //first check for preconditions 2887 boolean shouldErase = false; 2888 List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes(); 2889 for (Symbol s : ambiguousInOrder) { 2890 if ((s.flags() & ABSTRACT) == 0 || 2891 (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) { 2892 return Optional.empty(); 2893 } else if (s.type.hasTag(FORALL)) { 2894 shouldErase = true; 2895 } 2896 } 2897 //then merge abstracts 2898 for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) { 2899 outer: for (Symbol s : ambiguousInOrder) { 2900 Type mt = memberType(site, s); 2901 List<Type> allThrown = mt.getThrownTypes(); 2902 for (Symbol s2 : ambiguousInOrder) { 2903 if (s != s2) { 2904 Type mt2 = memberType(site, s2); 2905 if (!isSubSignature(mt, mt2) || 2906 !mostSpecificReturnCheck.test(mt, mt2, this)) { 2907 //ambiguity cannot be resolved 2908 continue outer; 2909 } else { 2910 List<Type> thrownTypes2 = mt2.getThrownTypes(); 2911 if (!mt.hasTag(FORALL) && shouldErase) { 2912 thrownTypes2 = erasure(thrownTypes2); 2913 } else if (mt.hasTag(FORALL)) { 2914 //subsignature implies that if most specific is generic, then all other 2915 //methods are too 2916 Assert.check(mt2.hasTag(FORALL)); 2917 // if both are generic methods, adjust thrown types ahead of intersection computation 2918 thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments()); 2919 } 2920 allThrown = chk.intersect(allThrown, thrownTypes2); 2921 } 2922 } 2923 } 2924 return (allThrown == mt.getThrownTypes()) ? 2925 Optional.of(s) : 2926 Optional.of(new MethodSymbol( 2927 s.flags(), 2928 s.name, 2929 createMethodTypeWithThrown(s.type, allThrown), 2930 s.owner) { 2931 @Override 2932 public Symbol baseSymbol() { 2933 return s; 2934 } 2935 }); 2936 } 2937 } 2938 return Optional.empty(); 2939 } 2940 2941 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site"> 2942 class ImplementationCache { 2943 2944 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>(); 2945 2946 class Entry { 2947 final MethodSymbol cachedImpl; 2948 final Predicate<Symbol> implFilter; 2949 final boolean checkResult; 2950 final int prevMark; 2951 2952 public Entry(MethodSymbol cachedImpl, 2953 Predicate<Symbol> scopeFilter, 2954 boolean checkResult, 2955 int prevMark) { 2956 this.cachedImpl = cachedImpl; 2957 this.implFilter = scopeFilter; 2958 this.checkResult = checkResult; 2959 this.prevMark = prevMark; 2960 } 2961 2962 boolean matches(Predicate<Symbol> scopeFilter, boolean checkResult, int mark) { 2963 return this.implFilter == scopeFilter && 2964 this.checkResult == checkResult && 2965 this.prevMark == mark; 2966 } 2967 } 2968 2969 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) { 2970 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms); 2971 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null; 2972 if (cache == null) { 2973 cache = new HashMap<>(); 2974 _map.put(ms, new SoftReference<>(cache)); 2975 } 2976 Entry e = cache.get(origin); 2977 CompoundScope members = membersClosure(origin.type, true); 2978 if (e == null || 2979 !e.matches(implFilter, checkResult, members.getMark())) { 2980 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter); 2981 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark())); 2982 return impl; 2983 } 2984 else { 2985 return e.cachedImpl; 2986 } 2987 } 2988 2989 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) { 2990 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) { 2991 t = skipTypeVars(t, false); 2992 TypeSymbol c = t.tsym; 2993 Symbol bestSoFar = null; 2994 for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) { 2995 if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) { 2996 bestSoFar = sym; 2997 if ((sym.flags() & ABSTRACT) == 0) { 2998 //if concrete impl is found, exit immediately 2999 break; 3000 } 3001 } 3002 } 3003 if (bestSoFar != null) { 3004 //return either the (only) concrete implementation or the first abstract one 3005 return (MethodSymbol)bestSoFar; 3006 } 3007 } 3008 return null; 3009 } 3010 } 3011 3012 private ImplementationCache implCache = new ImplementationCache(); 3013 3014 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Predicate<Symbol> implFilter) { 3015 return implCache.get(ms, origin, checkResult, implFilter); 3016 } 3017 // </editor-fold> 3018 3019 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site"> 3020 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> { 3021 3022 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>(); 3023 3024 Set<TypeSymbol> seenTypes = new HashSet<>(); 3025 3026 class MembersScope extends CompoundScope { 3027 3028 CompoundScope scope; 3029 3030 public MembersScope(CompoundScope scope) { 3031 super(scope.owner); 3032 this.scope = scope; 3033 } 3034 3035 Predicate<Symbol> combine(Predicate<Symbol> sf) { 3036 return s -> !s.owner.isInterface() && (sf == null || sf.test(s)); 3037 } 3038 3039 @Override 3040 public Iterable<Symbol> getSymbols(Predicate<Symbol> sf, LookupKind lookupKind) { 3041 return scope.getSymbols(combine(sf), lookupKind); 3042 } 3043 3044 @Override 3045 public Iterable<Symbol> getSymbolsByName(Name name, Predicate<Symbol> sf, LookupKind lookupKind) { 3046 return scope.getSymbolsByName(name, combine(sf), lookupKind); 3047 } 3048 3049 @Override 3050 public int getMark() { 3051 return scope.getMark(); 3052 } 3053 } 3054 3055 CompoundScope nilScope; 3056 3057 /** members closure visitor methods **/ 3058 3059 public CompoundScope visitType(Type t, Void _unused) { 3060 if (nilScope == null) { 3061 nilScope = new CompoundScope(syms.noSymbol); 3062 } 3063 return nilScope; 3064 } 3065 3066 @Override 3067 public CompoundScope visitClassType(ClassType t, Void _unused) { 3068 if (!seenTypes.add(t.tsym)) { 3069 //this is possible when an interface is implemented in multiple 3070 //superclasses, or when a class hierarchy is circular - in such 3071 //cases we don't need to recurse (empty scope is returned) 3072 return new CompoundScope(t.tsym); 3073 } 3074 try { 3075 seenTypes.add(t.tsym); 3076 ClassSymbol csym = (ClassSymbol)t.tsym; 3077 CompoundScope membersClosure = _map.get(csym); 3078 if (membersClosure == null) { 3079 membersClosure = new CompoundScope(csym); 3080 for (Type i : interfaces(t)) { 3081 membersClosure.prependSubScope(visit(i, null)); 3082 } 3083 membersClosure.prependSubScope(visit(supertype(t), null)); 3084 membersClosure.prependSubScope(csym.members()); 3085 _map.put(csym, membersClosure); 3086 } 3087 return membersClosure; 3088 } 3089 finally { 3090 seenTypes.remove(t.tsym); 3091 } 3092 } 3093 3094 @Override 3095 public CompoundScope visitTypeVar(TypeVar t, Void _unused) { 3096 return visit(t.getUpperBound(), null); 3097 } 3098 } 3099 3100 private MembersClosureCache membersCache = new MembersClosureCache(); 3101 3102 public CompoundScope membersClosure(Type site, boolean skipInterface) { 3103 CompoundScope cs = membersCache.visit(site, null); 3104 Assert.checkNonNull(cs, () -> "type " + site); 3105 return skipInterface ? membersCache.new MembersScope(cs) : cs; 3106 } 3107 // </editor-fold> 3108 3109 3110 /** Return first abstract member of class `sym'. 3111 */ 3112 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) { 3113 try { 3114 return firstUnimplementedAbstractImpl(sym, sym); 3115 } catch (CompletionFailure ex) { 3116 chk.completionError(enter.getEnv(sym).tree.pos(), ex); 3117 return null; 3118 } 3119 } 3120 //where: 3121 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) { 3122 MethodSymbol undef = null; 3123 // Do not bother to search in classes that are not abstract, 3124 // since they cannot have abstract members. 3125 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) { 3126 Scope s = c.members(); 3127 for (Symbol sym : s.getSymbols(NON_RECURSIVE)) { 3128 if (sym.kind == MTH && 3129 (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) { 3130 MethodSymbol absmeth = (MethodSymbol)sym; 3131 MethodSymbol implmeth = absmeth.implementation(impl, this, true); 3132 if (implmeth == null || implmeth == absmeth) { 3133 //look for default implementations 3134 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head; 3135 if (prov != null && prov.overrides(absmeth, impl, this, true)) { 3136 implmeth = prov; 3137 } 3138 } 3139 if (implmeth == null || implmeth == absmeth) { 3140 undef = absmeth; 3141 break; 3142 } 3143 } 3144 } 3145 if (undef == null) { 3146 Type st = supertype(c.type); 3147 if (st.hasTag(CLASS)) 3148 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym); 3149 } 3150 for (List<Type> l = interfaces(c.type); 3151 undef == null && l.nonEmpty(); 3152 l = l.tail) { 3153 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym); 3154 } 3155 } 3156 return undef; 3157 } 3158 3159 public class CandidatesCache { 3160 public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>(); 3161 3162 class Entry { 3163 Type site; 3164 MethodSymbol msym; 3165 3166 Entry(Type site, MethodSymbol msym) { 3167 this.site = site; 3168 this.msym = msym; 3169 } 3170 3171 @Override 3172 public boolean equals(Object obj) { 3173 return (obj instanceof Entry entry) 3174 && entry.msym == msym 3175 && isSameType(site, entry.site); 3176 } 3177 3178 @Override 3179 public int hashCode() { 3180 return Types.this.hashCode(site) & ~msym.hashCode(); 3181 } 3182 } 3183 3184 public List<MethodSymbol> get(Entry e) { 3185 return cache.get(e); 3186 } 3187 3188 public void put(Entry e, List<MethodSymbol> msymbols) { 3189 cache.put(e, msymbols); 3190 } 3191 } 3192 3193 public CandidatesCache candidatesCache = new CandidatesCache(); 3194 3195 //where 3196 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) { 3197 CandidatesCache.Entry e = candidatesCache.new Entry(site, ms); 3198 List<MethodSymbol> candidates = candidatesCache.get(e); 3199 if (candidates == null) { 3200 Predicate<Symbol> filter = new MethodFilter(ms, site); 3201 List<MethodSymbol> candidates2 = List.nil(); 3202 for (Symbol s : membersClosure(site, false).getSymbols(filter)) { 3203 if (!site.tsym.isInterface() && !s.owner.isInterface()) { 3204 return List.of((MethodSymbol)s); 3205 } else if (!candidates2.contains(s)) { 3206 candidates2 = candidates2.prepend((MethodSymbol)s); 3207 } 3208 } 3209 candidates = prune(candidates2); 3210 candidatesCache.put(e, candidates); 3211 } 3212 return candidates; 3213 } 3214 3215 public List<MethodSymbol> prune(List<MethodSymbol> methods) { 3216 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>(); 3217 for (MethodSymbol m1 : methods) { 3218 boolean isMin_m1 = true; 3219 for (MethodSymbol m2 : methods) { 3220 if (m1 == m2) continue; 3221 if (m2.owner != m1.owner && 3222 asSuper(m2.owner.type, m1.owner) != null) { 3223 isMin_m1 = false; 3224 break; 3225 } 3226 } 3227 if (isMin_m1) 3228 methodsMin.append(m1); 3229 } 3230 return methodsMin.toList(); 3231 } 3232 // where 3233 private class MethodFilter implements Predicate<Symbol> { 3234 3235 Symbol msym; 3236 Type site; 3237 3238 MethodFilter(Symbol msym, Type site) { 3239 this.msym = msym; 3240 this.site = site; 3241 } 3242 3243 @Override 3244 public boolean test(Symbol s) { 3245 return s.kind == MTH && 3246 s.name == msym.name && 3247 (s.flags() & SYNTHETIC) == 0 && 3248 s.isInheritedIn(site.tsym, Types.this) && 3249 overrideEquivalent(memberType(site, s), memberType(site, msym)); 3250 } 3251 } 3252 // </editor-fold> 3253 3254 /** 3255 * Does t have the same arguments as s? It is assumed that both 3256 * types are (possibly polymorphic) method types. Monomorphic 3257 * method types "have the same arguments", if their argument lists 3258 * are equal. Polymorphic method types "have the same arguments", 3259 * if they have the same arguments after renaming all type 3260 * variables of one to corresponding type variables in the other, 3261 * where correspondence is by position in the type parameter list. 3262 */ 3263 public boolean hasSameArgs(Type t, Type s) { 3264 return hasSameArgs(t, s, true); 3265 } 3266 3267 public boolean hasSameArgs(Type t, Type s, boolean strict) { 3268 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict); 3269 } 3270 3271 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) { 3272 return hasSameArgs.visit(t, s); 3273 } 3274 // where 3275 private class HasSameArgs extends TypeRelation { 3276 3277 boolean strict; 3278 3279 public HasSameArgs(boolean strict) { 3280 this.strict = strict; 3281 } 3282 3283 public Boolean visitType(Type t, Type s) { 3284 throw new AssertionError(); 3285 } 3286 3287 @Override 3288 public Boolean visitMethodType(MethodType t, Type s) { 3289 return s.hasTag(METHOD) 3290 && containsTypeEquivalent(t.argtypes, s.getParameterTypes()); 3291 } 3292 3293 @Override 3294 public Boolean visitForAll(ForAll t, Type s) { 3295 if (!s.hasTag(FORALL)) 3296 return strict ? false : visitMethodType(t.asMethodType(), s); 3297 3298 ForAll forAll = (ForAll)s; 3299 return hasSameBounds(t, forAll) 3300 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars)); 3301 } 3302 3303 @Override 3304 public Boolean visitErrorType(ErrorType t, Type s) { 3305 return false; 3306 } 3307 } 3308 3309 TypeRelation hasSameArgs_strict = new HasSameArgs(true); 3310 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false); 3311 3312 // </editor-fold> 3313 3314 // <editor-fold defaultstate="collapsed" desc="subst"> 3315 public List<Type> subst(List<Type> ts, 3316 List<Type> from, 3317 List<Type> to) { 3318 return ts.map(new Subst(from, to)); 3319 } 3320 3321 /** 3322 * Substitute all occurrences of a type in `from' with the 3323 * corresponding type in `to' in 't'. Match lists `from' and `to' 3324 * from the right: If lists have different length, discard leading 3325 * elements of the longer list. 3326 */ 3327 public Type subst(Type t, List<Type> from, List<Type> to) { 3328 return t.map(new Subst(from, to)); 3329 } 3330 3331 private class Subst extends StructuralTypeMapping<Void> { 3332 List<Type> from; 3333 List<Type> to; 3334 3335 public Subst(List<Type> from, List<Type> to) { 3336 int fromLength = from.length(); 3337 int toLength = to.length(); 3338 while (fromLength > toLength) { 3339 fromLength--; 3340 from = from.tail; 3341 } 3342 while (fromLength < toLength) { 3343 toLength--; 3344 to = to.tail; 3345 } 3346 this.from = from; 3347 this.to = to; 3348 } 3349 3350 @Override 3351 public Type visitTypeVar(TypeVar t, Void ignored) { 3352 for (List<Type> from = this.from, to = this.to; 3353 from.nonEmpty(); 3354 from = from.tail, to = to.tail) { 3355 if (t.equalsIgnoreMetadata(from.head)) { 3356 return to.head.withTypeVar(t); 3357 } 3358 } 3359 return t; 3360 } 3361 3362 @Override 3363 public Type visitClassType(ClassType t, Void ignored) { 3364 if (!t.isCompound()) { 3365 return super.visitClassType(t, ignored); 3366 } else { 3367 Type st = visit(supertype(t)); 3368 List<Type> is = visit(interfaces(t), ignored); 3369 if (st == supertype(t) && is == interfaces(t)) 3370 return t; 3371 else 3372 return makeIntersectionType(is.prepend(st)); 3373 } 3374 } 3375 3376 @Override 3377 public Type visitWildcardType(WildcardType t, Void ignored) { 3378 WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored); 3379 if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) { 3380 t2.type = wildUpperBound(t2.type); 3381 } 3382 return t2; 3383 } 3384 3385 @Override 3386 public Type visitForAll(ForAll t, Void ignored) { 3387 if (Type.containsAny(to, t.tvars)) { 3388 //perform alpha-renaming of free-variables in 't' 3389 //if 'to' types contain variables that are free in 't' 3390 List<Type> freevars = newInstances(t.tvars); 3391 t = new ForAll(freevars, 3392 Types.this.subst(t.qtype, t.tvars, freevars)); 3393 } 3394 List<Type> tvars1 = substBounds(t.tvars, from, to); 3395 Type qtype1 = visit(t.qtype); 3396 if (tvars1 == t.tvars && qtype1 == t.qtype) { 3397 return t; 3398 } else if (tvars1 == t.tvars) { 3399 return new ForAll(tvars1, qtype1) { 3400 @Override 3401 public boolean needsStripping() { 3402 return true; 3403 } 3404 }; 3405 } else { 3406 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) { 3407 @Override 3408 public boolean needsStripping() { 3409 return true; 3410 } 3411 }; 3412 } 3413 } 3414 } 3415 3416 public List<Type> substBounds(List<Type> tvars, 3417 List<Type> from, 3418 List<Type> to) { 3419 if (tvars.isEmpty()) 3420 return tvars; 3421 ListBuffer<Type> newBoundsBuf = new ListBuffer<>(); 3422 boolean changed = false; 3423 // calculate new bounds 3424 for (Type t : tvars) { 3425 TypeVar tv = (TypeVar) t; 3426 Type bound = subst(tv.getUpperBound(), from, to); 3427 if (bound != tv.getUpperBound()) 3428 changed = true; 3429 newBoundsBuf.append(bound); 3430 } 3431 if (!changed) 3432 return tvars; 3433 ListBuffer<Type> newTvars = new ListBuffer<>(); 3434 // create new type variables without bounds 3435 for (Type t : tvars) { 3436 newTvars.append(new TypeVar(t.tsym, null, syms.botType, 3437 t.getMetadata())); 3438 } 3439 // the new bounds should use the new type variables in place 3440 // of the old 3441 List<Type> newBounds = newBoundsBuf.toList(); 3442 from = tvars; 3443 to = newTvars.toList(); 3444 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) { 3445 newBounds.head = subst(newBounds.head, from, to); 3446 } 3447 newBounds = newBoundsBuf.toList(); 3448 // set the bounds of new type variables to the new bounds 3449 for (Type t : newTvars.toList()) { 3450 TypeVar tv = (TypeVar) t; 3451 tv.setUpperBound( newBounds.head ); 3452 newBounds = newBounds.tail; 3453 } 3454 return newTvars.toList(); 3455 } 3456 3457 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) { 3458 Type bound1 = subst(t.getUpperBound(), from, to); 3459 if (bound1 == t.getUpperBound()) 3460 return t; 3461 else { 3462 // create new type variable without bounds 3463 TypeVar tv = new TypeVar(t.tsym, null, syms.botType, 3464 t.getMetadata()); 3465 // the new bound should use the new type variable in place 3466 // of the old 3467 tv.setUpperBound( subst(bound1, List.of(t), List.of(tv)) ); 3468 return tv; 3469 } 3470 } 3471 // </editor-fold> 3472 3473 // <editor-fold defaultstate="collapsed" desc="hasSameBounds"> 3474 /** 3475 * Does t have the same bounds for quantified variables as s? 3476 */ 3477 public boolean hasSameBounds(ForAll t, ForAll s) { 3478 List<Type> l1 = t.tvars; 3479 List<Type> l2 = s.tvars; 3480 while (l1.nonEmpty() && l2.nonEmpty() && 3481 isSameType(l1.head.getUpperBound(), 3482 subst(l2.head.getUpperBound(), 3483 s.tvars, 3484 t.tvars))) { 3485 l1 = l1.tail; 3486 l2 = l2.tail; 3487 } 3488 return l1.isEmpty() && l2.isEmpty(); 3489 } 3490 // </editor-fold> 3491 3492 // <editor-fold defaultstate="collapsed" desc="newInstances"> 3493 /** Create new vector of type variables from list of variables 3494 * changing all recursive bounds from old to new list. 3495 */ 3496 public List<Type> newInstances(List<Type> tvars) { 3497 List<Type> tvars1 = tvars.map(newInstanceFun); 3498 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) { 3499 TypeVar tv = (TypeVar) l.head; 3500 tv.setUpperBound( subst(tv.getUpperBound(), tvars, tvars1) ); 3501 } 3502 return tvars1; 3503 } 3504 private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() { 3505 @Override 3506 public TypeVar visitTypeVar(TypeVar t, Void _unused) { 3507 return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata()); 3508 } 3509 }; 3510 // </editor-fold> 3511 3512 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) { 3513 return original.accept(methodWithParameters, newParams); 3514 } 3515 // where 3516 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() { 3517 public Type visitType(Type t, List<Type> newParams) { 3518 throw new IllegalArgumentException("Not a method type: " + t); 3519 } 3520 public Type visitMethodType(MethodType t, List<Type> newParams) { 3521 return new MethodType(newParams, t.restype, t.thrown, t.tsym); 3522 } 3523 public Type visitForAll(ForAll t, List<Type> newParams) { 3524 return new ForAll(t.tvars, t.qtype.accept(this, newParams)); 3525 } 3526 }; 3527 3528 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) { 3529 return original.accept(methodWithThrown, newThrown); 3530 } 3531 // where 3532 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() { 3533 public Type visitType(Type t, List<Type> newThrown) { 3534 throw new IllegalArgumentException("Not a method type: " + t); 3535 } 3536 public Type visitMethodType(MethodType t, List<Type> newThrown) { 3537 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym); 3538 } 3539 public Type visitForAll(ForAll t, List<Type> newThrown) { 3540 return new ForAll(t.tvars, t.qtype.accept(this, newThrown)); 3541 } 3542 }; 3543 3544 public Type createMethodTypeWithReturn(Type original, Type newReturn) { 3545 return original.accept(methodWithReturn, newReturn); 3546 } 3547 // where 3548 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() { 3549 public Type visitType(Type t, Type newReturn) { 3550 throw new IllegalArgumentException("Not a method type: " + t); 3551 } 3552 public Type visitMethodType(MethodType t, Type newReturn) { 3553 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) { 3554 @Override 3555 public Type baseType() { 3556 return t; 3557 } 3558 }; 3559 } 3560 public Type visitForAll(ForAll t, Type newReturn) { 3561 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) { 3562 @Override 3563 public Type baseType() { 3564 return t; 3565 } 3566 }; 3567 } 3568 }; 3569 3570 // <editor-fold defaultstate="collapsed" desc="createErrorType"> 3571 public Type createErrorType(Type originalType) { 3572 return new ErrorType(originalType, syms.errSymbol); 3573 } 3574 3575 public Type createErrorType(ClassSymbol c, Type originalType) { 3576 return new ErrorType(c, originalType); 3577 } 3578 3579 public Type createErrorType(Name name, TypeSymbol container, Type originalType) { 3580 return new ErrorType(name, container, originalType); 3581 } 3582 // </editor-fold> 3583 3584 // <editor-fold defaultstate="collapsed" desc="rank"> 3585 /** 3586 * The rank of a class is the length of the longest path between 3587 * the class and java.lang.Object in the class inheritance 3588 * graph. Undefined for all but reference types. 3589 */ 3590 public int rank(Type t) { 3591 switch(t.getTag()) { 3592 case CLASS: { 3593 ClassType cls = (ClassType)t; 3594 if (cls.rank_field < 0) { 3595 Name fullname = cls.tsym.getQualifiedName(); 3596 if (fullname == names.java_lang_Object) 3597 cls.rank_field = 0; 3598 else { 3599 int r = rank(supertype(cls)); 3600 for (List<Type> l = interfaces(cls); 3601 l.nonEmpty(); 3602 l = l.tail) { 3603 if (rank(l.head) > r) 3604 r = rank(l.head); 3605 } 3606 cls.rank_field = r + 1; 3607 } 3608 } 3609 return cls.rank_field; 3610 } 3611 case TYPEVAR: { 3612 TypeVar tvar = (TypeVar)t; 3613 if (tvar.rank_field < 0) { 3614 int r = rank(supertype(tvar)); 3615 for (List<Type> l = interfaces(tvar); 3616 l.nonEmpty(); 3617 l = l.tail) { 3618 if (rank(l.head) > r) r = rank(l.head); 3619 } 3620 tvar.rank_field = r + 1; 3621 } 3622 return tvar.rank_field; 3623 } 3624 case ERROR: 3625 case NONE: 3626 return 0; 3627 default: 3628 throw new AssertionError(); 3629 } 3630 } 3631 // </editor-fold> 3632 3633 /** 3634 * Helper method for generating a string representation of a given type 3635 * accordingly to a given locale 3636 */ 3637 public String toString(Type t, Locale locale) { 3638 return Printer.createStandardPrinter(messages).visit(t, locale); 3639 } 3640 3641 /** 3642 * Helper method for generating a string representation of a given type 3643 * accordingly to a given locale 3644 */ 3645 public String toString(Symbol t, Locale locale) { 3646 return Printer.createStandardPrinter(messages).visit(t, locale); 3647 } 3648 3649 // <editor-fold defaultstate="collapsed" desc="toString"> 3650 /** 3651 * This toString is slightly more descriptive than the one on Type. 3652 * 3653 * @deprecated Types.toString(Type t, Locale l) provides better support 3654 * for localization 3655 */ 3656 @Deprecated 3657 public String toString(Type t) { 3658 if (t.hasTag(FORALL)) { 3659 ForAll forAll = (ForAll)t; 3660 return typaramsString(forAll.tvars) + forAll.qtype; 3661 } 3662 return "" + t; 3663 } 3664 // where 3665 private String typaramsString(List<Type> tvars) { 3666 StringBuilder s = new StringBuilder(); 3667 s.append('<'); 3668 boolean first = true; 3669 for (Type t : tvars) { 3670 if (!first) s.append(", "); 3671 first = false; 3672 appendTyparamString(((TypeVar)t), s); 3673 } 3674 s.append('>'); 3675 return s.toString(); 3676 } 3677 private void appendTyparamString(TypeVar t, StringBuilder buf) { 3678 buf.append(t); 3679 if (t.getUpperBound() == null || 3680 t.getUpperBound().tsym.getQualifiedName() == names.java_lang_Object) 3681 return; 3682 buf.append(" extends "); // Java syntax; no need for i18n 3683 Type bound = t.getUpperBound(); 3684 if (!bound.isCompound()) { 3685 buf.append(bound); 3686 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) { 3687 buf.append(supertype(t)); 3688 for (Type intf : interfaces(t)) { 3689 buf.append('&'); 3690 buf.append(intf); 3691 } 3692 } else { 3693 // No superclass was given in bounds. 3694 // In this case, supertype is Object, erasure is first interface. 3695 boolean first = true; 3696 for (Type intf : interfaces(t)) { 3697 if (!first) buf.append('&'); 3698 first = false; 3699 buf.append(intf); 3700 } 3701 } 3702 } 3703 // </editor-fold> 3704 3705 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types"> 3706 /** 3707 * A cache for closures. 3708 * 3709 * <p>A closure is a list of all the supertypes and interfaces of 3710 * a class or interface type, ordered by ClassSymbol.precedes 3711 * (that is, subclasses come first, arbitrarily but fixed 3712 * otherwise). 3713 */ 3714 private Map<Type,List<Type>> closureCache = new HashMap<>(); 3715 3716 /** 3717 * Returns the closure of a class or interface type. 3718 */ 3719 public List<Type> closure(Type t) { 3720 List<Type> cl = closureCache.get(t); 3721 if (cl == null) { 3722 Type st = supertype(t); 3723 if (!t.isCompound()) { 3724 if (st.hasTag(CLASS)) { 3725 cl = insert(closure(st), t); 3726 } else if (st.hasTag(TYPEVAR)) { 3727 cl = closure(st).prepend(t); 3728 } else { 3729 cl = List.of(t); 3730 } 3731 } else { 3732 cl = closure(supertype(t)); 3733 } 3734 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) 3735 cl = union(cl, closure(l.head)); 3736 closureCache.put(t, cl); 3737 } 3738 return cl; 3739 } 3740 3741 /** 3742 * Collect types into a new closure (using a {@code ClosureHolder}) 3743 */ 3744 public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) { 3745 return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip), 3746 ClosureHolder::add, 3747 ClosureHolder::merge, 3748 ClosureHolder::closure); 3749 } 3750 //where 3751 class ClosureHolder { 3752 List<Type> closure; 3753 final boolean minClosure; 3754 final BiPredicate<Type, Type> shouldSkip; 3755 3756 ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) { 3757 this.closure = List.nil(); 3758 this.minClosure = minClosure; 3759 this.shouldSkip = shouldSkip; 3760 } 3761 3762 void add(Type type) { 3763 closure = insert(closure, type, shouldSkip); 3764 } 3765 3766 ClosureHolder merge(ClosureHolder other) { 3767 closure = union(closure, other.closure, shouldSkip); 3768 return this; 3769 } 3770 3771 List<Type> closure() { 3772 return minClosure ? closureMin(closure) : closure; 3773 } 3774 } 3775 3776 BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym; 3777 3778 /** 3779 * Insert a type in a closure 3780 */ 3781 public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) { 3782 if (cl.isEmpty()) { 3783 return cl.prepend(t); 3784 } else if (shouldSkip.test(t, cl.head)) { 3785 return cl; 3786 } else if (t.tsym.precedes(cl.head.tsym, this)) { 3787 return cl.prepend(t); 3788 } else { 3789 // t comes after head, or the two are unrelated 3790 return insert(cl.tail, t, shouldSkip).prepend(cl.head); 3791 } 3792 } 3793 3794 public List<Type> insert(List<Type> cl, Type t) { 3795 return insert(cl, t, basicClosureSkip); 3796 } 3797 3798 /** 3799 * Form the union of two closures 3800 */ 3801 public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) { 3802 if (cl1.isEmpty()) { 3803 return cl2; 3804 } else if (cl2.isEmpty()) { 3805 return cl1; 3806 } else if (shouldSkip.test(cl1.head, cl2.head)) { 3807 return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head); 3808 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) { 3809 return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head); 3810 } else { 3811 return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head); 3812 } 3813 } 3814 3815 public List<Type> union(List<Type> cl1, List<Type> cl2) { 3816 return union(cl1, cl2, basicClosureSkip); 3817 } 3818 3819 /** 3820 * Intersect two closures 3821 */ 3822 public List<Type> intersect(List<Type> cl1, List<Type> cl2) { 3823 if (cl1 == cl2) 3824 return cl1; 3825 if (cl1.isEmpty() || cl2.isEmpty()) 3826 return List.nil(); 3827 if (cl1.head.tsym.precedes(cl2.head.tsym, this)) 3828 return intersect(cl1.tail, cl2); 3829 if (cl2.head.tsym.precedes(cl1.head.tsym, this)) 3830 return intersect(cl1, cl2.tail); 3831 if (isSameType(cl1.head, cl2.head)) 3832 return intersect(cl1.tail, cl2.tail).prepend(cl1.head); 3833 if (cl1.head.tsym == cl2.head.tsym && 3834 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) { 3835 if (cl1.head.isParameterized() && cl2.head.isParameterized()) { 3836 Type merge = merge(cl1.head,cl2.head); 3837 return intersect(cl1.tail, cl2.tail).prepend(merge); 3838 } 3839 if (cl1.head.isRaw() || cl2.head.isRaw()) 3840 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head)); 3841 } 3842 return intersect(cl1.tail, cl2.tail); 3843 } 3844 // where 3845 class TypePair { 3846 final Type t1; 3847 final Type t2;; 3848 3849 TypePair(Type t1, Type t2) { 3850 this.t1 = t1; 3851 this.t2 = t2; 3852 } 3853 @Override 3854 public int hashCode() { 3855 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2); 3856 } 3857 @Override 3858 public boolean equals(Object obj) { 3859 return (obj instanceof TypePair typePair) 3860 && isSameType(t1, typePair.t1) 3861 && isSameType(t2, typePair.t2); 3862 } 3863 } 3864 Set<TypePair> mergeCache = new HashSet<>(); 3865 private Type merge(Type c1, Type c2) { 3866 ClassType class1 = (ClassType) c1; 3867 List<Type> act1 = class1.getTypeArguments(); 3868 ClassType class2 = (ClassType) c2; 3869 List<Type> act2 = class2.getTypeArguments(); 3870 ListBuffer<Type> merged = new ListBuffer<>(); 3871 List<Type> typarams = class1.tsym.type.getTypeArguments(); 3872 3873 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) { 3874 if (containsType(act1.head, act2.head)) { 3875 merged.append(act1.head); 3876 } else if (containsType(act2.head, act1.head)) { 3877 merged.append(act2.head); 3878 } else { 3879 TypePair pair = new TypePair(c1, c2); 3880 Type m; 3881 if (mergeCache.add(pair)) { 3882 m = new WildcardType(lub(wildUpperBound(act1.head), 3883 wildUpperBound(act2.head)), 3884 BoundKind.EXTENDS, 3885 syms.boundClass); 3886 mergeCache.remove(pair); 3887 } else { 3888 m = new WildcardType(syms.objectType, 3889 BoundKind.UNBOUND, 3890 syms.boundClass); 3891 } 3892 merged.append(m.withTypeVar(typarams.head)); 3893 } 3894 act1 = act1.tail; 3895 act2 = act2.tail; 3896 typarams = typarams.tail; 3897 } 3898 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty()); 3899 // There is no spec detailing how type annotations are to 3900 // be inherited. So set it to noAnnotations for now 3901 return new ClassType(class1.getEnclosingType(), merged.toList(), 3902 class1.tsym); 3903 } 3904 3905 /** 3906 * Return the minimum type of a closure, a compound type if no 3907 * unique minimum exists. 3908 */ 3909 private Type compoundMin(List<Type> cl) { 3910 if (cl.isEmpty()) return syms.objectType; 3911 List<Type> compound = closureMin(cl); 3912 if (compound.isEmpty()) 3913 return null; 3914 else if (compound.tail.isEmpty()) 3915 return compound.head; 3916 else 3917 return makeIntersectionType(compound); 3918 } 3919 3920 /** 3921 * Return the minimum types of a closure, suitable for computing 3922 * compoundMin or glb. 3923 */ 3924 private List<Type> closureMin(List<Type> cl) { 3925 ListBuffer<Type> classes = new ListBuffer<>(); 3926 ListBuffer<Type> interfaces = new ListBuffer<>(); 3927 Set<Type> toSkip = new HashSet<>(); 3928 while (!cl.isEmpty()) { 3929 Type current = cl.head; 3930 boolean keep = !toSkip.contains(current); 3931 if (keep && current.hasTag(TYPEVAR)) { 3932 // skip lower-bounded variables with a subtype in cl.tail 3933 for (Type t : cl.tail) { 3934 if (isSubtypeNoCapture(t, current)) { 3935 keep = false; 3936 break; 3937 } 3938 } 3939 } 3940 if (keep) { 3941 if (current.isInterface()) 3942 interfaces.append(current); 3943 else 3944 classes.append(current); 3945 for (Type t : cl.tail) { 3946 // skip supertypes of 'current' in cl.tail 3947 if (isSubtypeNoCapture(current, t)) 3948 toSkip.add(t); 3949 } 3950 } 3951 cl = cl.tail; 3952 } 3953 return classes.appendList(interfaces).toList(); 3954 } 3955 3956 /** 3957 * Return the least upper bound of list of types. if the lub does 3958 * not exist return null. 3959 */ 3960 public Type lub(List<Type> ts) { 3961 return lub(ts.toArray(new Type[ts.length()])); 3962 } 3963 3964 /** 3965 * Return the least upper bound (lub) of set of types. If the lub 3966 * does not exist return the type of null (bottom). 3967 */ 3968 public Type lub(Type... ts) { 3969 final int UNKNOWN_BOUND = 0; 3970 final int ARRAY_BOUND = 1; 3971 final int CLASS_BOUND = 2; 3972 3973 int[] kinds = new int[ts.length]; 3974 3975 int boundkind = UNKNOWN_BOUND; 3976 for (int i = 0 ; i < ts.length ; i++) { 3977 Type t = ts[i]; 3978 switch (t.getTag()) { 3979 case CLASS: 3980 boundkind |= kinds[i] = CLASS_BOUND; 3981 break; 3982 case ARRAY: 3983 boundkind |= kinds[i] = ARRAY_BOUND; 3984 break; 3985 case TYPEVAR: 3986 do { 3987 t = t.getUpperBound(); 3988 } while (t.hasTag(TYPEVAR)); 3989 if (t.hasTag(ARRAY)) { 3990 boundkind |= kinds[i] = ARRAY_BOUND; 3991 } else { 3992 boundkind |= kinds[i] = CLASS_BOUND; 3993 } 3994 break; 3995 default: 3996 kinds[i] = UNKNOWN_BOUND; 3997 if (t.isPrimitive()) 3998 return syms.errType; 3999 } 4000 } 4001 switch (boundkind) { 4002 case 0: 4003 return syms.botType; 4004 4005 case ARRAY_BOUND: 4006 // calculate lub(A[], B[]) 4007 Type[] elements = new Type[ts.length]; 4008 for (int i = 0 ; i < ts.length ; i++) { 4009 Type elem = elements[i] = elemTypeFun.apply(ts[i]); 4010 if (elem.isPrimitive()) { 4011 // if a primitive type is found, then return 4012 // arraySuperType unless all the types are the 4013 // same 4014 Type first = ts[0]; 4015 for (int j = 1 ; j < ts.length ; j++) { 4016 if (!isSameType(first, ts[j])) { 4017 // lub(int[], B[]) is Cloneable & Serializable 4018 return arraySuperType(); 4019 } 4020 } 4021 // all the array types are the same, return one 4022 // lub(int[], int[]) is int[] 4023 return first; 4024 } 4025 } 4026 // lub(A[], B[]) is lub(A, B)[] 4027 return new ArrayType(lub(elements), syms.arrayClass); 4028 4029 case CLASS_BOUND: 4030 // calculate lub(A, B) 4031 int startIdx = 0; 4032 for (int i = 0; i < ts.length ; i++) { 4033 Type t = ts[i]; 4034 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) { 4035 break; 4036 } else { 4037 startIdx++; 4038 } 4039 } 4040 Assert.check(startIdx < ts.length); 4041 //step 1 - compute erased candidate set (EC) 4042 List<Type> cl = erasedSupertypes(ts[startIdx]); 4043 for (int i = startIdx + 1 ; i < ts.length ; i++) { 4044 Type t = ts[i]; 4045 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) 4046 cl = intersect(cl, erasedSupertypes(t)); 4047 } 4048 //step 2 - compute minimal erased candidate set (MEC) 4049 List<Type> mec = closureMin(cl); 4050 //step 3 - for each element G in MEC, compute lci(Inv(G)) 4051 List<Type> candidates = List.nil(); 4052 for (Type erasedSupertype : mec) { 4053 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym)); 4054 for (int i = startIdx + 1 ; i < ts.length ; i++) { 4055 Type superType = asSuper(ts[i], erasedSupertype.tsym); 4056 lci = intersect(lci, superType != null ? List.of(superType) : List.nil()); 4057 } 4058 candidates = candidates.appendList(lci); 4059 } 4060 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that 4061 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn)) 4062 return compoundMin(candidates); 4063 4064 default: 4065 // calculate lub(A, B[]) 4066 List<Type> classes = List.of(arraySuperType()); 4067 for (int i = 0 ; i < ts.length ; i++) { 4068 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays 4069 classes = classes.prepend(ts[i]); 4070 } 4071 // lub(A, B[]) is lub(A, arraySuperType) 4072 return lub(classes); 4073 } 4074 } 4075 // where 4076 List<Type> erasedSupertypes(Type t) { 4077 ListBuffer<Type> buf = new ListBuffer<>(); 4078 for (Type sup : closure(t)) { 4079 if (sup.hasTag(TYPEVAR)) { 4080 buf.append(sup); 4081 } else { 4082 buf.append(erasure(sup)); 4083 } 4084 } 4085 return buf.toList(); 4086 } 4087 4088 private Type arraySuperType; 4089 private Type arraySuperType() { 4090 // initialized lazily to avoid problems during compiler startup 4091 if (arraySuperType == null) { 4092 // JLS 10.8: all arrays implement Cloneable and Serializable. 4093 arraySuperType = makeIntersectionType(List.of(syms.serializableType, 4094 syms.cloneableType), true); 4095 } 4096 return arraySuperType; 4097 } 4098 // </editor-fold> 4099 4100 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound"> 4101 public Type glb(List<Type> ts) { 4102 Type t1 = ts.head; 4103 for (Type t2 : ts.tail) { 4104 if (t1.isErroneous()) 4105 return t1; 4106 t1 = glb(t1, t2); 4107 } 4108 return t1; 4109 } 4110 //where 4111 public Type glb(Type t, Type s) { 4112 if (s == null) 4113 return t; 4114 else if (t.isPrimitive() || s.isPrimitive()) 4115 return syms.errType; 4116 else if (isSubtypeNoCapture(t, s)) 4117 return t; 4118 else if (isSubtypeNoCapture(s, t)) 4119 return s; 4120 4121 List<Type> closure = union(closure(t), closure(s)); 4122 return glbFlattened(closure, t); 4123 } 4124 //where 4125 /** 4126 * Perform glb for a list of non-primitive, non-error, non-compound types; 4127 * redundant elements are removed. Bounds should be ordered according to 4128 * {@link Symbol#precedes(TypeSymbol,Types)}. 4129 * 4130 * @param flatBounds List of type to glb 4131 * @param errT Original type to use if the result is an error type 4132 */ 4133 private Type glbFlattened(List<Type> flatBounds, Type errT) { 4134 List<Type> bounds = closureMin(flatBounds); 4135 4136 if (bounds.isEmpty()) { // length == 0 4137 return syms.objectType; 4138 } else if (bounds.tail.isEmpty()) { // length == 1 4139 return bounds.head; 4140 } else { // length > 1 4141 int classCount = 0; 4142 List<Type> cvars = List.nil(); 4143 List<Type> lowers = List.nil(); 4144 for (Type bound : bounds) { 4145 if (!bound.isInterface()) { 4146 classCount++; 4147 Type lower = cvarLowerBound(bound); 4148 if (bound != lower && !lower.hasTag(BOT)) { 4149 cvars = cvars.append(bound); 4150 lowers = lowers.append(lower); 4151 } 4152 } 4153 } 4154 if (classCount > 1) { 4155 if (lowers.isEmpty()) { 4156 return createErrorType(errT); 4157 } else { 4158 // try again with lower bounds included instead of capture variables 4159 List<Type> newBounds = bounds.diff(cvars).appendList(lowers); 4160 return glb(newBounds); 4161 } 4162 } 4163 } 4164 return makeIntersectionType(bounds); 4165 } 4166 // </editor-fold> 4167 4168 // <editor-fold defaultstate="collapsed" desc="hashCode"> 4169 /** 4170 * Compute a hash code on a type. 4171 */ 4172 public int hashCode(Type t) { 4173 return hashCode(t, false); 4174 } 4175 4176 public int hashCode(Type t, boolean strict) { 4177 return strict ? 4178 hashCodeStrictVisitor.visit(t) : 4179 hashCodeVisitor.visit(t); 4180 } 4181 // where 4182 private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor(); 4183 private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() { 4184 @Override 4185 public Integer visitTypeVar(TypeVar t, Void ignored) { 4186 return System.identityHashCode(t); 4187 } 4188 }; 4189 4190 private static class HashCodeVisitor extends UnaryVisitor<Integer> { 4191 public Integer visitType(Type t, Void ignored) { 4192 return t.getTag().ordinal(); 4193 } 4194 4195 @Override 4196 public Integer visitClassType(ClassType t, Void ignored) { 4197 int result = visit(t.getEnclosingType()); 4198 result *= 127; 4199 result += t.tsym.flatName().hashCode(); 4200 for (Type s : t.getTypeArguments()) { 4201 result *= 127; 4202 result += visit(s); 4203 } 4204 return result; 4205 } 4206 4207 @Override 4208 public Integer visitMethodType(MethodType t, Void ignored) { 4209 int h = METHOD.ordinal(); 4210 for (List<Type> thisargs = t.argtypes; 4211 thisargs.tail != null; 4212 thisargs = thisargs.tail) 4213 h = (h << 5) + visit(thisargs.head); 4214 return (h << 5) + visit(t.restype); 4215 } 4216 4217 @Override 4218 public Integer visitWildcardType(WildcardType t, Void ignored) { 4219 int result = t.kind.hashCode(); 4220 if (t.type != null) { 4221 result *= 127; 4222 result += visit(t.type); 4223 } 4224 return result; 4225 } 4226 4227 @Override 4228 public Integer visitArrayType(ArrayType t, Void ignored) { 4229 return visit(t.elemtype) + 12; 4230 } 4231 4232 @Override 4233 public Integer visitTypeVar(TypeVar t, Void ignored) { 4234 return System.identityHashCode(t); 4235 } 4236 4237 @Override 4238 public Integer visitUndetVar(UndetVar t, Void ignored) { 4239 return System.identityHashCode(t); 4240 } 4241 4242 @Override 4243 public Integer visitErrorType(ErrorType t, Void ignored) { 4244 return 0; 4245 } 4246 } 4247 // </editor-fold> 4248 4249 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable"> 4250 /** 4251 * Does t have a result that is a subtype of the result type of s, 4252 * suitable for covariant returns? It is assumed that both types 4253 * are (possibly polymorphic) method types. Monomorphic method 4254 * types are handled in the obvious way. Polymorphic method types 4255 * require renaming all type variables of one to corresponding 4256 * type variables in the other, where correspondence is by 4257 * position in the type parameter list. */ 4258 public boolean resultSubtype(Type t, Type s, Warner warner) { 4259 List<Type> tvars = t.getTypeArguments(); 4260 List<Type> svars = s.getTypeArguments(); 4261 Type tres = t.getReturnType(); 4262 Type sres = subst(s.getReturnType(), svars, tvars); 4263 return covariantReturnType(tres, sres, warner); 4264 } 4265 4266 /** 4267 * Return-Type-Substitutable. 4268 * @jls 8.4.5 Method Result 4269 */ 4270 public boolean returnTypeSubstitutable(Type r1, Type r2) { 4271 if (hasSameArgs(r1, r2)) 4272 return resultSubtype(r1, r2, noWarnings); 4273 else 4274 return covariantReturnType(r1.getReturnType(), 4275 erasure(r2.getReturnType()), 4276 noWarnings); 4277 } 4278 4279 public boolean returnTypeSubstitutable(Type r1, 4280 Type r2, Type r2res, 4281 Warner warner) { 4282 if (isSameType(r1.getReturnType(), r2res)) 4283 return true; 4284 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive()) 4285 return false; 4286 4287 if (hasSameArgs(r1, r2)) 4288 return covariantReturnType(r1.getReturnType(), r2res, warner); 4289 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner)) 4290 return true; 4291 if (!isSubtype(r1.getReturnType(), erasure(r2res))) 4292 return false; 4293 warner.warn(LintCategory.UNCHECKED); 4294 return true; 4295 } 4296 4297 /** 4298 * Is t an appropriate return type in an overrider for a 4299 * method that returns s? 4300 */ 4301 public boolean covariantReturnType(Type t, Type s, Warner warner) { 4302 return 4303 isSameType(t, s) || 4304 !t.isPrimitive() && 4305 !s.isPrimitive() && 4306 isAssignable(t, s, warner); 4307 } 4308 // </editor-fold> 4309 4310 // <editor-fold defaultstate="collapsed" desc="Box/unbox support"> 4311 /** 4312 * Return the class that boxes the given primitive. 4313 */ 4314 public ClassSymbol boxedClass(Type t) { 4315 return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]); 4316 } 4317 4318 /** 4319 * Return the boxed type if 't' is primitive, otherwise return 't' itself. 4320 */ 4321 public Type boxedTypeOrType(Type t) { 4322 return t.isPrimitive() ? 4323 boxedClass(t).type : 4324 t; 4325 } 4326 4327 /** 4328 * Return the primitive type corresponding to a boxed type. 4329 */ 4330 public Type unboxedType(Type t) { 4331 if (t.hasTag(ERROR)) 4332 return Type.noType; 4333 for (int i=0; i<syms.boxedName.length; i++) { 4334 Name box = syms.boxedName[i]; 4335 if (box != null && 4336 asSuper(t, syms.enterClass(syms.java_base, box)) != null) 4337 return syms.typeOfTag[i]; 4338 } 4339 return Type.noType; 4340 } 4341 4342 /** 4343 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself. 4344 */ 4345 public Type unboxedTypeOrType(Type t) { 4346 Type unboxedType = unboxedType(t); 4347 return unboxedType.hasTag(NONE) ? t : unboxedType; 4348 } 4349 // </editor-fold> 4350 4351 // <editor-fold defaultstate="collapsed" desc="Capture conversion"> 4352 /* 4353 * JLS 5.1.10 Capture Conversion: 4354 * 4355 * Let G name a generic type declaration with n formal type 4356 * parameters A1 ... An with corresponding bounds U1 ... Un. There 4357 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>, 4358 * where, for 1 <= i <= n: 4359 * 4360 * + If Ti is a wildcard type argument (4.5.1) of the form ? then 4361 * Si is a fresh type variable whose upper bound is 4362 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null 4363 * type. 4364 * 4365 * + If Ti is a wildcard type argument of the form ? extends Bi, 4366 * then Si is a fresh type variable whose upper bound is 4367 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is 4368 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is 4369 * a compile-time error if for any two classes (not interfaces) 4370 * Vi and Vj,Vi is not a subclass of Vj or vice versa. 4371 * 4372 * + If Ti is a wildcard type argument of the form ? super Bi, 4373 * then Si is a fresh type variable whose upper bound is 4374 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi. 4375 * 4376 * + Otherwise, Si = Ti. 4377 * 4378 * Capture conversion on any type other than a parameterized type 4379 * (4.5) acts as an identity conversion (5.1.1). Capture 4380 * conversions never require a special action at run time and 4381 * therefore never throw an exception at run time. 4382 * 4383 * Capture conversion is not applied recursively. 4384 */ 4385 /** 4386 * Capture conversion as specified by the JLS. 4387 */ 4388 4389 public List<Type> capture(List<Type> ts) { 4390 List<Type> buf = List.nil(); 4391 for (Type t : ts) { 4392 buf = buf.prepend(capture(t)); 4393 } 4394 return buf.reverse(); 4395 } 4396 4397 public Type capture(Type t) { 4398 if (!t.hasTag(CLASS)) { 4399 return t; 4400 } 4401 if (t.getEnclosingType() != Type.noType) { 4402 Type capturedEncl = capture(t.getEnclosingType()); 4403 if (capturedEncl != t.getEnclosingType()) { 4404 Type type1 = memberType(capturedEncl, t.tsym); 4405 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments()); 4406 } 4407 } 4408 ClassType cls = (ClassType)t; 4409 if (cls.isRaw() || !cls.isParameterized()) 4410 return cls; 4411 4412 ClassType G = (ClassType)cls.asElement().asType(); 4413 List<Type> A = G.getTypeArguments(); 4414 List<Type> T = cls.getTypeArguments(); 4415 List<Type> S = freshTypeVariables(T); 4416 4417 List<Type> currentA = A; 4418 List<Type> currentT = T; 4419 List<Type> currentS = S; 4420 boolean captured = false; 4421 while (!currentA.isEmpty() && 4422 !currentT.isEmpty() && 4423 !currentS.isEmpty()) { 4424 if (currentS.head != currentT.head) { 4425 captured = true; 4426 WildcardType Ti = (WildcardType)currentT.head; 4427 Type Ui = currentA.head.getUpperBound(); 4428 CapturedType Si = (CapturedType)currentS.head; 4429 if (Ui == null) 4430 Ui = syms.objectType; 4431 switch (Ti.kind) { 4432 case UNBOUND: 4433 Si.setUpperBound( subst(Ui, A, S) ); 4434 Si.lower = syms.botType; 4435 break; 4436 case EXTENDS: 4437 Si.setUpperBound( glb(Ti.getExtendsBound(), subst(Ui, A, S)) ); 4438 Si.lower = syms.botType; 4439 break; 4440 case SUPER: 4441 Si.setUpperBound( subst(Ui, A, S) ); 4442 Si.lower = Ti.getSuperBound(); 4443 break; 4444 } 4445 Type tmpBound = Si.getUpperBound().hasTag(UNDETVAR) ? ((UndetVar)Si.getUpperBound()).qtype : Si.getUpperBound(); 4446 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower; 4447 if (!Si.getUpperBound().hasTag(ERROR) && 4448 !Si.lower.hasTag(ERROR) && 4449 isSameType(tmpBound, tmpLower)) { 4450 currentS.head = Si.getUpperBound(); 4451 } 4452 } 4453 currentA = currentA.tail; 4454 currentT = currentT.tail; 4455 currentS = currentS.tail; 4456 } 4457 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty()) 4458 return erasure(t); // some "rare" type involved 4459 4460 if (captured) 4461 return new ClassType(cls.getEnclosingType(), S, cls.tsym, 4462 cls.getMetadata()); 4463 else 4464 return t; 4465 } 4466 // where 4467 public List<Type> freshTypeVariables(List<Type> types) { 4468 ListBuffer<Type> result = new ListBuffer<>(); 4469 for (Type t : types) { 4470 if (t.hasTag(WILDCARD)) { 4471 Type bound = ((WildcardType)t).getExtendsBound(); 4472 if (bound == null) 4473 bound = syms.objectType; 4474 result.append(new CapturedType(capturedName, 4475 syms.noSymbol, 4476 bound, 4477 syms.botType, 4478 (WildcardType)t)); 4479 } else { 4480 result.append(t); 4481 } 4482 } 4483 return result.toList(); 4484 } 4485 // </editor-fold> 4486 4487 // <editor-fold defaultstate="collapsed" desc="Internal utility methods"> 4488 private boolean sideCast(Type from, Type to, Warner warn) { 4489 // We are casting from type $from$ to type $to$, which are 4490 // non-final unrelated types. This method 4491 // tries to reject a cast by transferring type parameters 4492 // from $to$ to $from$ by common superinterfaces. 4493 boolean reverse = false; 4494 Type target = to; 4495 if ((to.tsym.flags() & INTERFACE) == 0) { 4496 Assert.check((from.tsym.flags() & INTERFACE) != 0); 4497 reverse = true; 4498 to = from; 4499 from = target; 4500 } 4501 List<Type> commonSupers = superClosure(to, erasure(from)); 4502 boolean giveWarning = commonSupers.isEmpty(); 4503 // The arguments to the supers could be unified here to 4504 // get a more accurate analysis 4505 while (commonSupers.nonEmpty()) { 4506 Type t1 = asSuper(from, commonSupers.head.tsym); 4507 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym); 4508 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments())) 4509 return false; 4510 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)); 4511 commonSupers = commonSupers.tail; 4512 } 4513 if (giveWarning && !isReifiable(reverse ? from : to)) 4514 warn.warn(LintCategory.UNCHECKED); 4515 return true; 4516 } 4517 4518 private boolean sideCastFinal(Type from, Type to, Warner warn) { 4519 // We are casting from type $from$ to type $to$, which are 4520 // unrelated types one of which is final and the other of 4521 // which is an interface. This method 4522 // tries to reject a cast by transferring type parameters 4523 // from the final class to the interface. 4524 boolean reverse = false; 4525 Type target = to; 4526 if ((to.tsym.flags() & INTERFACE) == 0) { 4527 Assert.check((from.tsym.flags() & INTERFACE) != 0); 4528 reverse = true; 4529 to = from; 4530 from = target; 4531 } 4532 Assert.check((from.tsym.flags() & FINAL) != 0); 4533 Type t1 = asSuper(from, to.tsym); 4534 if (t1 == null) return false; 4535 Type t2 = to; 4536 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments())) 4537 return false; 4538 if (!isReifiable(target) && 4539 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2))) 4540 warn.warn(LintCategory.UNCHECKED); 4541 return true; 4542 } 4543 4544 private boolean giveWarning(Type from, Type to) { 4545 List<Type> bounds = to.isCompound() ? 4546 directSupertypes(to) : List.of(to); 4547 for (Type b : bounds) { 4548 Type subFrom = asSub(from, b.tsym); 4549 if (b.isParameterized() && 4550 (!(isUnbounded(b) || 4551 isSubtype(from, b) || 4552 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) { 4553 return true; 4554 } 4555 } 4556 return false; 4557 } 4558 4559 private List<Type> superClosure(Type t, Type s) { 4560 List<Type> cl = List.nil(); 4561 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) { 4562 if (isSubtype(s, erasure(l.head))) { 4563 cl = insert(cl, l.head); 4564 } else { 4565 cl = union(cl, superClosure(l.head, s)); 4566 } 4567 } 4568 return cl; 4569 } 4570 4571 private boolean containsTypeEquivalent(Type t, Type s) { 4572 return isSameType(t, s) || // shortcut 4573 containsType(t, s) && containsType(s, t); 4574 } 4575 4576 // <editor-fold defaultstate="collapsed" desc="adapt"> 4577 /** 4578 * Adapt a type by computing a substitution which maps a source 4579 * type to a target type. 4580 * 4581 * @param source the source type 4582 * @param target the target type 4583 * @param from the type variables of the computed substitution 4584 * @param to the types of the computed substitution. 4585 */ 4586 public void adapt(Type source, 4587 Type target, 4588 ListBuffer<Type> from, 4589 ListBuffer<Type> to) throws AdaptFailure { 4590 new Adapter(from, to).adapt(source, target); 4591 } 4592 4593 class Adapter extends SimpleVisitor<Void, Type> { 4594 4595 ListBuffer<Type> from; 4596 ListBuffer<Type> to; 4597 Map<Symbol,Type> mapping; 4598 4599 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) { 4600 this.from = from; 4601 this.to = to; 4602 mapping = new HashMap<>(); 4603 } 4604 4605 public void adapt(Type source, Type target) throws AdaptFailure { 4606 visit(source, target); 4607 List<Type> fromList = from.toList(); 4608 List<Type> toList = to.toList(); 4609 while (!fromList.isEmpty()) { 4610 Type val = mapping.get(fromList.head.tsym); 4611 if (toList.head != val) 4612 toList.head = val; 4613 fromList = fromList.tail; 4614 toList = toList.tail; 4615 } 4616 } 4617 4618 @Override 4619 public Void visitClassType(ClassType source, Type target) throws AdaptFailure { 4620 if (target.hasTag(CLASS)) 4621 adaptRecursive(source.allparams(), target.allparams()); 4622 return null; 4623 } 4624 4625 @Override 4626 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure { 4627 if (target.hasTag(ARRAY)) 4628 adaptRecursive(elemtype(source), elemtype(target)); 4629 return null; 4630 } 4631 4632 @Override 4633 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure { 4634 if (source.isExtendsBound()) 4635 adaptRecursive(wildUpperBound(source), wildUpperBound(target)); 4636 else if (source.isSuperBound()) 4637 adaptRecursive(wildLowerBound(source), wildLowerBound(target)); 4638 return null; 4639 } 4640 4641 @Override 4642 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure { 4643 // Check to see if there is 4644 // already a mapping for $source$, in which case 4645 // the old mapping will be merged with the new 4646 Type val = mapping.get(source.tsym); 4647 if (val != null) { 4648 if (val.isSuperBound() && target.isSuperBound()) { 4649 val = isSubtype(wildLowerBound(val), wildLowerBound(target)) 4650 ? target : val; 4651 } else if (val.isExtendsBound() && target.isExtendsBound()) { 4652 val = isSubtype(wildUpperBound(val), wildUpperBound(target)) 4653 ? val : target; 4654 } else if (!isSameType(val, target)) { 4655 throw new AdaptFailure(); 4656 } 4657 } else { 4658 val = target; 4659 from.append(source); 4660 to.append(target); 4661 } 4662 mapping.put(source.tsym, val); 4663 return null; 4664 } 4665 4666 @Override 4667 public Void visitType(Type source, Type target) { 4668 return null; 4669 } 4670 4671 private Set<TypePair> cache = new HashSet<>(); 4672 4673 private void adaptRecursive(Type source, Type target) { 4674 TypePair pair = new TypePair(source, target); 4675 if (cache.add(pair)) { 4676 try { 4677 visit(source, target); 4678 } finally { 4679 cache.remove(pair); 4680 } 4681 } 4682 } 4683 4684 private void adaptRecursive(List<Type> source, List<Type> target) { 4685 if (source.length() == target.length()) { 4686 while (source.nonEmpty()) { 4687 adaptRecursive(source.head, target.head); 4688 source = source.tail; 4689 target = target.tail; 4690 } 4691 } 4692 } 4693 } 4694 4695 public static class AdaptFailure extends RuntimeException { 4696 static final long serialVersionUID = -7490231548272701566L; 4697 } 4698 4699 private void adaptSelf(Type t, 4700 ListBuffer<Type> from, 4701 ListBuffer<Type> to) { 4702 try { 4703 //if (t.tsym.type != t) 4704 adapt(t.tsym.type, t, from, to); 4705 } catch (AdaptFailure ex) { 4706 // Adapt should never fail calculating a mapping from 4707 // t.tsym.type to t as there can be no merge problem. 4708 throw new AssertionError(ex); 4709 } 4710 } 4711 // </editor-fold> 4712 4713 /** 4714 * Rewrite all type variables (universal quantifiers) in the given 4715 * type to wildcards (existential quantifiers). This is used to 4716 * determine if a cast is allowed. For example, if high is true 4717 * and {@code T <: Number}, then {@code List<T>} is rewritten to 4718 * {@code List<? extends Number>}. Since {@code List<Integer> <: 4719 * List<? extends Number>} a {@code List<T>} can be cast to {@code 4720 * List<Integer>} with a warning. 4721 * @param t a type 4722 * @param high if true return an upper bound; otherwise a lower 4723 * bound 4724 * @param rewriteTypeVars only rewrite captured wildcards if false; 4725 * otherwise rewrite all type variables 4726 * @return the type rewritten with wildcards (existential 4727 * quantifiers) only 4728 */ 4729 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) { 4730 return new Rewriter(high, rewriteTypeVars).visit(t); 4731 } 4732 4733 class Rewriter extends UnaryVisitor<Type> { 4734 4735 boolean high; 4736 boolean rewriteTypeVars; 4737 4738 Rewriter(boolean high, boolean rewriteTypeVars) { 4739 this.high = high; 4740 this.rewriteTypeVars = rewriteTypeVars; 4741 } 4742 4743 @Override 4744 public Type visitClassType(ClassType t, Void s) { 4745 ListBuffer<Type> rewritten = new ListBuffer<>(); 4746 boolean changed = false; 4747 for (Type arg : t.allparams()) { 4748 Type bound = visit(arg); 4749 if (arg != bound) { 4750 changed = true; 4751 } 4752 rewritten.append(bound); 4753 } 4754 if (changed) 4755 return subst(t.tsym.type, 4756 t.tsym.type.allparams(), 4757 rewritten.toList()); 4758 else 4759 return t; 4760 } 4761 4762 public Type visitType(Type t, Void s) { 4763 return t; 4764 } 4765 4766 @Override 4767 public Type visitCapturedType(CapturedType t, Void s) { 4768 Type w_bound = t.wildcard.type; 4769 Type bound = w_bound.contains(t) ? 4770 erasure(w_bound) : 4771 visit(w_bound); 4772 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind); 4773 } 4774 4775 @Override 4776 public Type visitTypeVar(TypeVar t, Void s) { 4777 if (rewriteTypeVars) { 4778 Type bound = t.getUpperBound().contains(t) ? 4779 erasure(t.getUpperBound()) : 4780 visit(t.getUpperBound()); 4781 return rewriteAsWildcardType(bound, t, EXTENDS); 4782 } else { 4783 return t; 4784 } 4785 } 4786 4787 @Override 4788 public Type visitWildcardType(WildcardType t, Void s) { 4789 Type bound2 = visit(t.type); 4790 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind); 4791 } 4792 4793 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) { 4794 switch (bk) { 4795 case EXTENDS: return high ? 4796 makeExtendsWildcard(B(bound), formal) : 4797 makeExtendsWildcard(syms.objectType, formal); 4798 case SUPER: return high ? 4799 makeSuperWildcard(syms.botType, formal) : 4800 makeSuperWildcard(B(bound), formal); 4801 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal); 4802 default: 4803 Assert.error("Invalid bound kind " + bk); 4804 return null; 4805 } 4806 } 4807 4808 Type B(Type t) { 4809 while (t.hasTag(WILDCARD)) { 4810 WildcardType w = (WildcardType)t; 4811 t = high ? 4812 w.getExtendsBound() : 4813 w.getSuperBound(); 4814 if (t == null) { 4815 t = high ? syms.objectType : syms.botType; 4816 } 4817 } 4818 return t; 4819 } 4820 } 4821 4822 4823 /** 4824 * Create a wildcard with the given upper (extends) bound; create 4825 * an unbounded wildcard if bound is Object. 4826 * 4827 * @param bound the upper bound 4828 * @param formal the formal type parameter that will be 4829 * substituted by the wildcard 4830 */ 4831 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) { 4832 if (bound == syms.objectType) { 4833 return new WildcardType(syms.objectType, 4834 BoundKind.UNBOUND, 4835 syms.boundClass, 4836 formal); 4837 } else { 4838 return new WildcardType(bound, 4839 BoundKind.EXTENDS, 4840 syms.boundClass, 4841 formal); 4842 } 4843 } 4844 4845 /** 4846 * Create a wildcard with the given lower (super) bound; create an 4847 * unbounded wildcard if bound is bottom (type of {@code null}). 4848 * 4849 * @param bound the lower bound 4850 * @param formal the formal type parameter that will be 4851 * substituted by the wildcard 4852 */ 4853 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) { 4854 if (bound.hasTag(BOT)) { 4855 return new WildcardType(syms.objectType, 4856 BoundKind.UNBOUND, 4857 syms.boundClass, 4858 formal); 4859 } else { 4860 return new WildcardType(bound, 4861 BoundKind.SUPER, 4862 syms.boundClass, 4863 formal); 4864 } 4865 } 4866 4867 /** 4868 * A wrapper for a type that allows use in sets. 4869 */ 4870 public static class UniqueType { 4871 public final Type type; 4872 final Types types; 4873 4874 public UniqueType(Type type, Types types) { 4875 this.type = type; 4876 this.types = types; 4877 } 4878 4879 public int hashCode() { 4880 return types.hashCode(type); 4881 } 4882 4883 public boolean equals(Object obj) { 4884 return (obj instanceof UniqueType uniqueType) && 4885 types.isSameType(type, uniqueType.type); 4886 } 4887 4888 public String toString() { 4889 return type.toString(); 4890 } 4891 4892 } 4893 // </editor-fold> 4894 4895 // <editor-fold defaultstate="collapsed" desc="Visitors"> 4896 /** 4897 * A default visitor for types. All visitor methods except 4898 * visitType are implemented by delegating to visitType. Concrete 4899 * subclasses must provide an implementation of visitType and can 4900 * override other methods as needed. 4901 * 4902 * @param <R> the return type of the operation implemented by this 4903 * visitor; use Void if no return type is needed. 4904 * @param <S> the type of the second argument (the first being the 4905 * type itself) of the operation implemented by this visitor; use 4906 * Void if a second argument is not needed. 4907 */ 4908 public abstract static class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> { 4909 public final R visit(Type t, S s) { return t.accept(this, s); } 4910 public R visitClassType(ClassType t, S s) { return visitType(t, s); } 4911 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); } 4912 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); } 4913 public R visitMethodType(MethodType t, S s) { return visitType(t, s); } 4914 public R visitPackageType(PackageType t, S s) { return visitType(t, s); } 4915 public R visitModuleType(ModuleType t, S s) { return visitType(t, s); } 4916 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); } 4917 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); } 4918 public R visitForAll(ForAll t, S s) { return visitType(t, s); } 4919 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); } 4920 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); } 4921 } 4922 4923 /** 4924 * A default visitor for symbols. All visitor methods except 4925 * visitSymbol are implemented by delegating to visitSymbol. Concrete 4926 * subclasses must provide an implementation of visitSymbol and can 4927 * override other methods as needed. 4928 * 4929 * @param <R> the return type of the operation implemented by this 4930 * visitor; use Void if no return type is needed. 4931 * @param <S> the type of the second argument (the first being the 4932 * symbol itself) of the operation implemented by this visitor; use 4933 * Void if a second argument is not needed. 4934 */ 4935 public abstract static class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> { 4936 public final R visit(Symbol s, S arg) { return s.accept(this, arg); } 4937 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); } 4938 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); } 4939 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); } 4940 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); } 4941 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); } 4942 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); } 4943 } 4944 4945 /** 4946 * A <em>simple</em> visitor for types. This visitor is simple as 4947 * captured wildcards, for-all types (generic methods), and 4948 * undetermined type variables (part of inference) are hidden. 4949 * Captured wildcards are hidden by treating them as type 4950 * variables and the rest are hidden by visiting their qtypes. 4951 * 4952 * @param <R> the return type of the operation implemented by this 4953 * visitor; use Void if no return type is needed. 4954 * @param <S> the type of the second argument (the first being the 4955 * type itself) of the operation implemented by this visitor; use 4956 * Void if a second argument is not needed. 4957 */ 4958 public abstract static class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> { 4959 @Override 4960 public R visitCapturedType(CapturedType t, S s) { 4961 return visitTypeVar(t, s); 4962 } 4963 @Override 4964 public R visitForAll(ForAll t, S s) { 4965 return visit(t.qtype, s); 4966 } 4967 @Override 4968 public R visitUndetVar(UndetVar t, S s) { 4969 return visit(t.qtype, s); 4970 } 4971 } 4972 4973 /** 4974 * A plain relation on types. That is a 2-ary function on the 4975 * form Type × Type → Boolean. 4976 * <!-- In plain text: Type x Type -> Boolean --> 4977 */ 4978 public abstract static class TypeRelation extends SimpleVisitor<Boolean,Type> {} 4979 4980 /** 4981 * A convenience visitor for implementing operations that only 4982 * require one argument (the type itself), that is, unary 4983 * operations. 4984 * 4985 * @param <R> the return type of the operation implemented by this 4986 * visitor; use Void if no return type is needed. 4987 */ 4988 public abstract static class UnaryVisitor<R> extends SimpleVisitor<R,Void> { 4989 public final R visit(Type t) { return t.accept(this, null); } 4990 } 4991 4992 /** 4993 * A visitor for implementing a mapping from types to types. The 4994 * default behavior of this class is to implement the identity 4995 * mapping (mapping a type to itself). This can be overridden in 4996 * subclasses. 4997 * 4998 * @param <S> the type of the second argument (the first being the 4999 * type itself) of this mapping; use Void if a second argument is 5000 * not needed. 5001 */ 5002 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> { 5003 public final Type visit(Type t) { return t.accept(this, null); } 5004 public Type visitType(Type t, S s) { return t; } 5005 } 5006 5007 /** 5008 * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}. 5009 * This class implements the functional interface {@code Function}, that allows it to be used 5010 * fluently in stream-like processing. 5011 */ 5012 public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> { 5013 @Override 5014 public Type apply(Type type) { return visit(type); } 5015 5016 List<Type> visit(List<Type> ts, S s) { 5017 return ts.map(t -> visit(t, s)); 5018 } 5019 5020 @Override 5021 public Type visitCapturedType(CapturedType t, S s) { 5022 return visitTypeVar(t, s); 5023 } 5024 } 5025 // </editor-fold> 5026 5027 // <editor-fold defaultstate="collapsed" desc="Unconditionality"> 5028 /** Check unconditionality between any combination of reference or primitive types. 5029 * 5030 * Rules: 5031 * an identity conversion 5032 * a widening reference conversion 5033 * a widening primitive conversion (delegates to `checkUnconditionallyExactPrimitives`) 5034 * a boxing conversion 5035 * a boxing conversion followed by a widening reference conversion 5036 * 5037 * @param source Source primitive or reference type 5038 * @param target Target primitive or reference type 5039 */ 5040 public boolean isUnconditionallyExact(Type source, Type target) { 5041 if (isSameType(source, target)) { 5042 return true; 5043 } 5044 5045 return target.isPrimitive() 5046 ? isUnconditionallyExactPrimitives(source, target) 5047 : isSubtype(boxedTypeOrType(erasure(source)), target); 5048 } 5049 5050 /** Check unconditionality between primitive types. 5051 * 5052 * - widening from one integral type to another, 5053 * - widening from one floating point type to another, 5054 * - widening from byte, short, or char to a floating point type, 5055 * - widening from int to double. 5056 * 5057 * @param selectorType Type of selector 5058 * @param targetType Target type 5059 */ 5060 public boolean isUnconditionallyExactPrimitives(Type selectorType, Type targetType) { 5061 if (isSameType(selectorType, targetType)) { 5062 return true; 5063 } 5064 5065 return (selectorType.isPrimitive() && targetType.isPrimitive()) && 5066 ((selectorType.hasTag(BYTE) && !targetType.hasTag(CHAR)) || 5067 (selectorType.hasTag(SHORT) && (selectorType.getTag().isStrictSubRangeOf(targetType.getTag()))) || 5068 (selectorType.hasTag(CHAR) && (selectorType.getTag().isStrictSubRangeOf(targetType.getTag()))) || 5069 (selectorType.hasTag(INT) && (targetType.hasTag(DOUBLE) || targetType.hasTag(LONG))) || 5070 (selectorType.hasTag(FLOAT) && (selectorType.getTag().isStrictSubRangeOf(targetType.getTag())))); 5071 } 5072 // </editor-fold> 5073 5074 // <editor-fold defaultstate="collapsed" desc="Annotation support"> 5075 5076 public RetentionPolicy getRetention(Attribute.Compound a) { 5077 return getRetention(a.type.tsym); 5078 } 5079 5080 public RetentionPolicy getRetention(TypeSymbol sym) { 5081 RetentionPolicy vis = RetentionPolicy.CLASS; // the default 5082 Attribute.Compound c = sym.attribute(syms.retentionType.tsym); 5083 if (c != null) { 5084 Attribute value = c.member(names.value); 5085 if (value != null && value instanceof Attribute.Enum attributeEnum) { 5086 Name levelName = attributeEnum.value.name; 5087 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE; 5088 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS; 5089 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME; 5090 else ;// /* fail soft */ throw new AssertionError(levelName); 5091 } 5092 } 5093 return vis; 5094 } 5095 // </editor-fold> 5096 5097 // <editor-fold defaultstate="collapsed" desc="Signature Generation"> 5098 5099 public abstract static class SignatureGenerator { 5100 5101 public static class InvalidSignatureException extends RuntimeException { 5102 private static final long serialVersionUID = 0; 5103 5104 private final transient Type type; 5105 5106 InvalidSignatureException(Type type) { 5107 this.type = type; 5108 } 5109 5110 public Type type() { 5111 return type; 5112 } 5113 5114 @Override 5115 public Throwable fillInStackTrace() { 5116 // This is an internal exception; the stack trace is irrelevant. 5117 return this; 5118 } 5119 } 5120 5121 private final Types types; 5122 5123 protected abstract void append(char ch); 5124 protected abstract void append(byte[] ba); 5125 protected abstract void append(Name name); 5126 protected void classReference(ClassSymbol c) { /* by default: no-op */ } 5127 5128 protected SignatureGenerator(Types types) { 5129 this.types = types; 5130 } 5131 5132 protected void reportIllegalSignature(Type t) { 5133 throw new InvalidSignatureException(t); 5134 } 5135 5136 /** 5137 * Assemble signature of given type in string buffer. 5138 */ 5139 public void assembleSig(Type type) { 5140 switch (type.getTag()) { 5141 case BYTE: 5142 append('B'); 5143 break; 5144 case SHORT: 5145 append('S'); 5146 break; 5147 case CHAR: 5148 append('C'); 5149 break; 5150 case INT: 5151 append('I'); 5152 break; 5153 case LONG: 5154 append('J'); 5155 break; 5156 case FLOAT: 5157 append('F'); 5158 break; 5159 case DOUBLE: 5160 append('D'); 5161 break; 5162 case BOOLEAN: 5163 append('Z'); 5164 break; 5165 case VOID: 5166 append('V'); 5167 break; 5168 case CLASS: 5169 if (type.isCompound()) { 5170 reportIllegalSignature(type); 5171 } 5172 append('L'); 5173 assembleClassSig(type); 5174 append(';'); 5175 break; 5176 case ARRAY: 5177 ArrayType at = (ArrayType) type; 5178 append('['); 5179 assembleSig(at.elemtype); 5180 break; 5181 case METHOD: 5182 MethodType mt = (MethodType) type; 5183 append('('); 5184 assembleSig(mt.argtypes); 5185 append(')'); 5186 assembleSig(mt.restype); 5187 if (hasTypeVar(mt.thrown)) { 5188 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) { 5189 append('^'); 5190 assembleSig(l.head); 5191 } 5192 } 5193 break; 5194 case WILDCARD: { 5195 Type.WildcardType ta = (Type.WildcardType) type; 5196 switch (ta.kind) { 5197 case SUPER: 5198 append('-'); 5199 assembleSig(ta.type); 5200 break; 5201 case EXTENDS: 5202 append('+'); 5203 assembleSig(ta.type); 5204 break; 5205 case UNBOUND: 5206 append('*'); 5207 break; 5208 default: 5209 throw new AssertionError(ta.kind); 5210 } 5211 break; 5212 } 5213 case TYPEVAR: 5214 if (((TypeVar)type).isCaptured()) { 5215 reportIllegalSignature(type); 5216 } 5217 append('T'); 5218 append(type.tsym.name); 5219 append(';'); 5220 break; 5221 case FORALL: 5222 Type.ForAll ft = (Type.ForAll) type; 5223 assembleParamsSig(ft.tvars); 5224 assembleSig(ft.qtype); 5225 break; 5226 default: 5227 throw new AssertionError("typeSig " + type.getTag()); 5228 } 5229 } 5230 5231 public boolean hasTypeVar(List<Type> l) { 5232 while (l.nonEmpty()) { 5233 if (l.head.hasTag(TypeTag.TYPEVAR)) { 5234 return true; 5235 } 5236 l = l.tail; 5237 } 5238 return false; 5239 } 5240 5241 public void assembleClassSig(Type type) { 5242 ClassType ct = (ClassType) type; 5243 ClassSymbol c = (ClassSymbol) ct.tsym; 5244 classReference(c); 5245 Type outer = ct.getEnclosingType(); 5246 if (outer.allparams().nonEmpty()) { 5247 boolean rawOuter = 5248 c.owner.kind == MTH || // either a local class 5249 c.name == types.names.empty; // or anonymous 5250 assembleClassSig(rawOuter 5251 ? types.erasure(outer) 5252 : outer); 5253 append(rawOuter ? '$' : '.'); 5254 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname)); 5255 append(rawOuter 5256 ? c.flatname.subName(c.owner.enclClass().flatname.length() + 1) 5257 : c.name); 5258 } else { 5259 append(externalize(c.flatname)); 5260 } 5261 if (ct.getTypeArguments().nonEmpty()) { 5262 append('<'); 5263 assembleSig(ct.getTypeArguments()); 5264 append('>'); 5265 } 5266 } 5267 5268 public void assembleParamsSig(List<Type> typarams) { 5269 append('<'); 5270 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) { 5271 Type.TypeVar tvar = (Type.TypeVar) ts.head; 5272 append(tvar.tsym.name); 5273 List<Type> bounds = types.getBounds(tvar); 5274 if ((bounds.head.tsym.flags() & INTERFACE) != 0) { 5275 append(':'); 5276 } 5277 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) { 5278 append(':'); 5279 assembleSig(l.head); 5280 } 5281 } 5282 append('>'); 5283 } 5284 5285 public void assembleSig(List<Type> types) { 5286 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) { 5287 assembleSig(ts.head); 5288 } 5289 } 5290 } 5291 5292 public Type constantType(LoadableConstant c) { 5293 switch (c.poolTag()) { 5294 case ClassFile.CONSTANT_Class: 5295 return syms.classType; 5296 case ClassFile.CONSTANT_String: 5297 return syms.stringType; 5298 case ClassFile.CONSTANT_Integer: 5299 return syms.intType; 5300 case ClassFile.CONSTANT_Float: 5301 return syms.floatType; 5302 case ClassFile.CONSTANT_Long: 5303 return syms.longType; 5304 case ClassFile.CONSTANT_Double: 5305 return syms.doubleType; 5306 case ClassFile.CONSTANT_MethodHandle: 5307 return syms.methodHandleType; 5308 case ClassFile.CONSTANT_MethodType: 5309 return syms.methodTypeType; 5310 case ClassFile.CONSTANT_Dynamic: 5311 return ((DynamicVarSymbol)c).type; 5312 default: 5313 throw new AssertionError("Not a loadable constant: " + c.poolTag()); 5314 } 5315 } 5316 // </editor-fold> 5317 5318 public void newRound() { 5319 descCache._map.clear(); 5320 isDerivedRawCache.clear(); 5321 implCache._map.clear(); 5322 membersCache._map.clear(); 5323 closureCache.clear(); 5324 } 5325 } --- EOF ---