1 /* 2 * Copyright (c) 2003, 2019, 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.stream.Collector; 39 40 import javax.tools.JavaFileObject; 41 42 import com.sun.tools.javac.code.Attribute.RetentionPolicy; 43 import com.sun.tools.javac.code.Lint.LintCategory; 44 import com.sun.tools.javac.code.Source.Feature; 45 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound; 46 import com.sun.tools.javac.code.TypeMetadata.Entry.Kind; 47 import com.sun.tools.javac.comp.AttrContext; 48 import com.sun.tools.javac.comp.Check; 49 import com.sun.tools.javac.comp.Enter; 50 import com.sun.tools.javac.comp.Env; 51 import com.sun.tools.javac.comp.LambdaToMethod; 52 import com.sun.tools.javac.jvm.ClassFile; 53 import com.sun.tools.javac.jvm.Target; 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 boolean allowDefaultMethods; 96 final boolean mapCapturesToBounds; 97 final boolean allowValueBasedClasses; 98 final boolean injectTopInterfaceTypes; 99 final Check chk; 100 final Enter enter; 101 JCDiagnostic.Factory diags; 102 List<Warner> warnStack = List.nil(); 103 final Name capturedName; 104 105 public final Warner noWarnings; 106 107 // <editor-fold defaultstate="collapsed" desc="Instantiating"> 108 public static Types instance(Context context) { 109 Types instance = context.get(typesKey); 110 if (instance == null) 111 instance = new Types(context); 112 return instance; 113 } 114 115 protected Types(Context context) { 116 context.put(typesKey, this); 117 syms = Symtab.instance(context); 118 names = Names.instance(context); 119 Source source = Source.instance(context); 120 allowDefaultMethods = Feature.DEFAULT_METHODS.allowedInSource(source); 121 mapCapturesToBounds = Feature.MAP_CAPTURES_TO_BOUNDS.allowedInSource(source); 122 chk = Check.instance(context); 123 enter = Enter.instance(context); 124 capturedName = names.fromString("<captured wildcard>"); 125 messages = JavacMessages.instance(context); 126 diags = JCDiagnostic.Factory.instance(context); 127 noWarnings = new Warner(null); 128 Options options = Options.instance(context); 129 allowValueBasedClasses = options.isSet("allowValueBasedClasses"); 130 injectTopInterfaceTypes = Options.instance(context).isUnset("noTopInterfaceInjection") && 131 Feature.INLINE_TYPES.allowedInSource(source) && 132 Target.instance(context).hasTopInterfaces(); 133 } 134 // </editor-fold> 135 136 // <editor-fold defaultstate="collapsed" desc="bounds"> 137 /** 138 * Get a wildcard's upper bound, returning non-wildcards unchanged. 139 * @param t a type argument, either a wildcard or a type 140 */ 141 public Type wildUpperBound(Type t) { 142 if (t.hasTag(WILDCARD)) { 143 WildcardType w = (WildcardType) t; 144 if (w.isSuperBound()) 145 return w.bound == null ? syms.objectType : w.bound.getUpperBound(); 146 else 147 return wildUpperBound(w.type); 148 } 149 else return t; 150 } 151 152 /** 153 * Get a capture variable's upper bound, returning other types unchanged. 154 * @param t a type 155 */ 156 public Type cvarUpperBound(Type t) { 157 if (t.hasTag(TYPEVAR)) { 158 TypeVar v = (TypeVar) t; 159 return v.isCaptured() ? cvarUpperBound(v.getUpperBound()) : v; 160 } 161 else return t; 162 } 163 164 /** 165 * Get a wildcard's lower bound, returning non-wildcards unchanged. 166 * @param t a type argument, either a wildcard or a type 167 */ 168 public Type wildLowerBound(Type t) { 169 if (t.hasTag(WILDCARD)) { 170 WildcardType w = (WildcardType) t; 171 return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type); 172 } 173 else return t; 174 } 175 176 /** 177 * Get a capture variable's lower bound, returning other types unchanged. 178 * @param t a type 179 */ 180 public Type cvarLowerBound(Type t) { 181 if (t.hasTag(TYPEVAR) && ((TypeVar) t).isCaptured()) { 182 return cvarLowerBound(t.getLowerBound()); 183 } 184 else return t; 185 } 186 187 /** 188 * Recursively skip type-variables until a class/array type is found; capture conversion is then 189 * (optionally) applied to the resulting type. This is useful for i.e. computing a site that is 190 * suitable for a method lookup. 191 */ 192 public Type skipTypeVars(Type site, boolean capture) { 193 while (site.hasTag(TYPEVAR)) { 194 site = site.getUpperBound(); 195 } 196 return capture ? capture(site) : site; 197 } 198 // </editor-fold> 199 200 // <editor-fold defaultstate="collapsed" desc="projections"> 201 202 /** 203 * A projection kind. See {@link TypeProjection} 204 */ 205 enum ProjectionKind { 206 UPWARDS() { 207 @Override 208 ProjectionKind complement() { 209 return DOWNWARDS; 210 } 211 }, 212 DOWNWARDS() { 213 @Override 214 ProjectionKind complement() { 215 return UPWARDS; 216 } 217 }; 218 219 abstract ProjectionKind complement(); 220 } 221 222 /** 223 * This visitor performs upwards and downwards projections on types. 224 * 225 * A projection is defined as a function that takes a type T, a set of type variables V and that 226 * produces another type S. 227 * 228 * An upwards projection maps a type T into a type S such that (i) T has no variables in V, 229 * and (ii) S is an upper bound of T. 230 * 231 * A downwards projection maps a type T into a type S such that (i) T has no variables in V, 232 * and (ii) S is a lower bound of T. 233 * 234 * Note that projections are only allowed to touch variables in V. Therefore, it is possible for 235 * a projection to leave its input type unchanged if it does not contain any variables in V. 236 * 237 * Moreover, note that while an upwards projection is always defined (every type as an upper bound), 238 * a downwards projection is not always defined. 239 * 240 * Examples: 241 * 242 * {@code upwards(List<#CAP1>, [#CAP1]) = List<? extends String>, where #CAP1 <: String } 243 * {@code downwards(List<#CAP2>, [#CAP2]) = List<? super String>, where #CAP2 :> String } 244 * {@code upwards(List<#CAP1>, [#CAP2]) = List<#CAP1> } 245 * {@code downwards(List<#CAP1>, [#CAP1]) = not defined } 246 */ 247 class TypeProjection extends TypeMapping<ProjectionKind> { 248 249 List<Type> vars; 250 Set<Type> seen = new HashSet<>(); 251 252 public TypeProjection(List<Type> vars) { 253 this.vars = vars; 254 } 255 256 @Override 257 public Type visitClassType(ClassType t, ProjectionKind pkind) { 258 if (t.isCompound()) { 259 List<Type> components = directSupertypes(t); 260 List<Type> components1 = components.map(c -> c.map(this, pkind)); 261 if (components == components1) return t; 262 else return makeIntersectionType(components1); 263 } else { 264 Type outer = t.getEnclosingType(); 265 Type outer1 = visit(outer, pkind); 266 List<Type> typarams = t.getTypeArguments(); 267 List<Type> formals = t.tsym.type.getTypeArguments(); 268 ListBuffer<Type> typarams1 = new ListBuffer<>(); 269 boolean changed = false; 270 for (Type actual : typarams) { 271 Type t2 = mapTypeArgument(t, formals.head.getUpperBound(), actual, pkind); 272 if (t2.hasTag(BOT)) { 273 //not defined 274 return syms.botType; 275 } 276 typarams1.add(t2); 277 changed |= actual != t2; 278 formals = formals.tail; 279 } 280 if (outer1 == outer && !changed) return t; 281 else return new ClassType(outer1, typarams1.toList(), t.tsym, t.getMetadata()) { 282 @Override 283 protected boolean needsStripping() { 284 return true; 285 } 286 }; 287 } 288 } 289 290 @Override 291 public Type visitArrayType(ArrayType t, ProjectionKind s) { 292 Type elemtype = t.elemtype; 293 Type elemtype1 = visit(elemtype, s); 294 if (elemtype1 == elemtype) { 295 return t; 296 } else if (elemtype1.hasTag(BOT)) { 297 //undefined 298 return syms.botType; 299 } else { 300 return new ArrayType(elemtype1, t.tsym, t.metadata) { 301 @Override 302 protected boolean needsStripping() { 303 return true; 304 } 305 }; 306 } 307 } 308 309 @Override 310 public Type visitTypeVar(TypeVar t, ProjectionKind pkind) { 311 if (vars.contains(t)) { 312 if (seen.add(t)) { 313 try { 314 final Type bound; 315 switch (pkind) { 316 case UPWARDS: 317 bound = t.getUpperBound(); 318 break; 319 case DOWNWARDS: 320 bound = (t.getLowerBound() == null) ? 321 syms.botType : 322 t.getLowerBound(); 323 break; 324 default: 325 Assert.error(); 326 return null; 327 } 328 return bound.map(this, pkind); 329 } finally { 330 seen.remove(t); 331 } 332 } else { 333 //cycle 334 return pkind == ProjectionKind.UPWARDS ? 335 syms.objectType : syms.botType; 336 } 337 } else { 338 return t; 339 } 340 } 341 342 private Type mapTypeArgument(Type site, Type declaredBound, Type t, ProjectionKind pkind) { 343 return t.containsAny(vars) ? 344 t.map(new TypeArgumentProjection(site, declaredBound), pkind) : 345 t; 346 } 347 348 class TypeArgumentProjection extends TypeMapping<ProjectionKind> { 349 350 Type site; 351 Type declaredBound; 352 353 TypeArgumentProjection(Type site, Type declaredBound) { 354 this.site = site; 355 this.declaredBound = declaredBound; 356 } 357 358 @Override 359 public Type visitType(Type t, ProjectionKind pkind) { 360 //type argument is some type containing restricted vars 361 if (pkind == ProjectionKind.DOWNWARDS) { 362 //not defined 363 return syms.botType; 364 } 365 Type upper = t.map(TypeProjection.this, ProjectionKind.UPWARDS); 366 Type lower = t.map(TypeProjection.this, ProjectionKind.DOWNWARDS); 367 List<Type> formals = site.tsym.type.getTypeArguments(); 368 BoundKind bk; 369 Type bound; 370 if (!isSameType(upper, syms.objectType) && 371 (declaredBound.containsAny(formals) || 372 !isSubtype(declaredBound, upper))) { 373 bound = upper; 374 bk = EXTENDS; 375 } else if (!lower.hasTag(BOT)) { 376 bound = lower; 377 bk = SUPER; 378 } else { 379 bound = syms.objectType; 380 bk = UNBOUND; 381 } 382 return makeWildcard(bound, bk); 383 } 384 385 @Override 386 public Type visitWildcardType(WildcardType wt, ProjectionKind pkind) { 387 //type argument is some wildcard whose bound contains restricted vars 388 Type bound = syms.botType; 389 BoundKind bk = wt.kind; 390 switch (wt.kind) { 391 case EXTENDS: 392 bound = wt.type.map(TypeProjection.this, pkind); 393 if (bound.hasTag(BOT)) { 394 return syms.botType; 395 } 396 break; 397 case SUPER: 398 bound = wt.type.map(TypeProjection.this, pkind.complement()); 399 if (bound.hasTag(BOT)) { 400 bound = syms.objectType; 401 bk = UNBOUND; 402 } 403 break; 404 } 405 return makeWildcard(bound, bk); 406 } 407 408 private Type makeWildcard(Type bound, BoundKind bk) { 409 return new WildcardType(bound, bk, syms.boundClass) { 410 @Override 411 protected boolean needsStripping() { 412 return true; 413 } 414 }; 415 } 416 } 417 } 418 419 /** 420 * Computes an upward projection of given type, and vars. See {@link TypeProjection}. 421 * 422 * @param t the type to be projected 423 * @param vars the set of type variables to be mapped 424 * @return the type obtained as result of the projection 425 */ 426 public Type upward(Type t, List<Type> vars) { 427 return t.map(new TypeProjection(vars), ProjectionKind.UPWARDS); 428 } 429 430 /** 431 * Computes the set of captured variables mentioned in a given type. See {@link CaptureScanner}. 432 * This routine is typically used to computed the input set of variables to be used during 433 * an upwards projection (see {@link Types#upward(Type, List)}). 434 * 435 * @param t the type where occurrences of captured variables have to be found 436 * @return the set of captured variables found in t 437 */ 438 public List<Type> captures(Type t) { 439 CaptureScanner cs = new CaptureScanner(); 440 Set<Type> captures = new HashSet<>(); 441 cs.visit(t, captures); 442 return List.from(captures); 443 } 444 445 /** 446 * This visitor scans a type recursively looking for occurrences of captured type variables. 447 */ 448 class CaptureScanner extends SimpleVisitor<Void, Set<Type>> { 449 450 @Override 451 public Void visitType(Type t, Set<Type> types) { 452 return null; 453 } 454 455 @Override 456 public Void visitClassType(ClassType t, Set<Type> seen) { 457 if (t.isCompound()) { 458 directSupertypes(t).forEach(s -> visit(s, seen)); 459 } else { 460 t.allparams().forEach(ta -> visit(ta, seen)); 461 } 462 return null; 463 } 464 465 @Override 466 public Void visitArrayType(ArrayType t, Set<Type> seen) { 467 return visit(t.elemtype, seen); 468 } 469 470 @Override 471 public Void visitWildcardType(WildcardType t, Set<Type> seen) { 472 visit(t.type, seen); 473 return null; 474 } 475 476 @Override 477 public Void visitTypeVar(TypeVar t, Set<Type> seen) { 478 if ((t.tsym.flags() & Flags.SYNTHETIC) != 0 && seen.add(t)) { 479 visit(t.getUpperBound(), seen); 480 } 481 return null; 482 } 483 484 @Override 485 public Void visitCapturedType(CapturedType t, Set<Type> seen) { 486 if (seen.add(t)) { 487 visit(t.getUpperBound(), seen); 488 visit(t.getLowerBound(), seen); 489 } 490 return null; 491 } 492 } 493 494 // </editor-fold> 495 496 // <editor-fold defaultstate="collapsed" desc="isUnbounded"> 497 /** 498 * Checks that all the arguments to a class are unbounded 499 * wildcards or something else that doesn't make any restrictions 500 * on the arguments. If a class isUnbounded, a raw super- or 501 * subclass can be cast to it without a warning. 502 * @param t a type 503 * @return true iff the given type is unbounded or raw 504 */ 505 public boolean isUnbounded(Type t) { 506 return isUnbounded.visit(t); 507 } 508 // where 509 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() { 510 511 public Boolean visitType(Type t, Void ignored) { 512 return true; 513 } 514 515 @Override 516 public Boolean visitClassType(ClassType t, Void ignored) { 517 List<Type> parms = t.tsym.type.allparams(); 518 List<Type> args = t.allparams(); 519 while (parms.nonEmpty()) { 520 WildcardType unb = new WildcardType(syms.objectType, 521 BoundKind.UNBOUND, 522 syms.boundClass, 523 (TypeVar)parms.head); 524 if (!containsType(args.head, unb)) 525 return false; 526 parms = parms.tail; 527 args = args.tail; 528 } 529 return true; 530 } 531 }; 532 // </editor-fold> 533 534 // <editor-fold defaultstate="collapsed" desc="asSub"> 535 /** 536 * Return the least specific subtype of t that starts with symbol 537 * sym. If none exists, return null. The least specific subtype 538 * is determined as follows: 539 * 540 * <p>If there is exactly one parameterized instance of sym that is a 541 * subtype of t, that parameterized instance is returned.<br> 542 * Otherwise, if the plain type or raw type `sym' is a subtype of 543 * type t, the type `sym' itself is returned. Otherwise, null is 544 * returned. 545 */ 546 public Type asSub(Type t, Symbol sym) { 547 return asSub.visit(t, sym); 548 } 549 // where 550 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() { 551 552 public Type visitType(Type t, Symbol sym) { 553 return null; 554 } 555 556 @Override 557 public Type visitClassType(ClassType t, Symbol sym) { 558 if (t.tsym == sym) 559 return t; 560 Type base = asSuper(sym.type, t.tsym); 561 if (base == null) 562 return null; 563 ListBuffer<Type> from = new ListBuffer<>(); 564 ListBuffer<Type> to = new ListBuffer<>(); 565 try { 566 adapt(base, t, from, to); 567 } catch (AdaptFailure ex) { 568 return null; 569 } 570 Type res = subst(sym.type, from.toList(), to.toList()); 571 if (!isSubtype(res, t)) 572 return null; 573 ListBuffer<Type> openVars = new ListBuffer<>(); 574 for (List<Type> l = sym.type.allparams(); 575 l.nonEmpty(); l = l.tail) 576 if (res.contains(l.head) && !t.contains(l.head)) 577 openVars.append(l.head); 578 if (openVars.nonEmpty()) { 579 if (t.isRaw()) { 580 // The subtype of a raw type is raw 581 res = erasure(res); 582 } else { 583 // Unbound type arguments default to ? 584 List<Type> opens = openVars.toList(); 585 ListBuffer<Type> qs = new ListBuffer<>(); 586 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) { 587 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, 588 syms.boundClass, (TypeVar) iter.head)); 589 } 590 res = subst(res, opens, qs.toList()); 591 } 592 } 593 return res; 594 } 595 596 @Override 597 public Type visitErrorType(ErrorType t, Symbol sym) { 598 return t; 599 } 600 }; 601 // </editor-fold> 602 603 // <editor-fold defaultstate="collapsed" desc="isConvertible"> 604 /** 605 * Is t a subtype of or convertible via boxing/unboxing 606 * conversion to s? 607 */ 608 public boolean isConvertible(Type t, Type s, Warner warn) { 609 if (t.hasTag(ERROR)) { 610 return true; 611 } 612 613 boolean tValue = t.isValue(); 614 boolean sValue = s.isValue(); 615 if (tValue != sValue) { 616 return tValue ? 617 isSubtype(t.referenceProjection(), s) : 618 (!t.hasTag(BOT) || isValueBased(s)) && isSubtype(t, s.referenceProjection()); 619 } 620 621 boolean tPrimitive = t.isPrimitive(); 622 boolean sPrimitive = s.isPrimitive(); 623 if (tPrimitive == sPrimitive) { 624 return isSubtypeUnchecked(t, s, warn); 625 } 626 boolean tUndet = t.hasTag(UNDETVAR); 627 boolean sUndet = s.hasTag(UNDETVAR); 628 629 if (tUndet || sUndet) { 630 return tUndet ? 631 isSubtype(t, boxedTypeOrType(s)) : 632 isSubtype(boxedTypeOrType(t), s); 633 } 634 635 return tPrimitive 636 ? isSubtype(boxedClass(t).type, s) 637 : isSubtype(unboxedType(t), s); 638 } 639 640 /** 641 * Is t a subtype of or convertible via boxing/unboxing 642 * conversions to s? 643 */ 644 public boolean isConvertible(Type t, Type s) { 645 return isConvertible(t, s, noWarnings); 646 } 647 // </editor-fold> 648 649 // <editor-fold defaultstate="collapsed" desc="findSam"> 650 651 /** 652 * Exception used to report a function descriptor lookup failure. The exception 653 * wraps a diagnostic that can be used to generate more details error 654 * messages. 655 */ 656 public static class FunctionDescriptorLookupError extends RuntimeException { 657 private static final long serialVersionUID = 0; 658 659 transient JCDiagnostic diagnostic; 660 661 FunctionDescriptorLookupError() { 662 this.diagnostic = null; 663 } 664 665 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) { 666 this.diagnostic = diag; 667 return this; 668 } 669 670 public JCDiagnostic getDiagnostic() { 671 return diagnostic; 672 } 673 } 674 675 /** 676 * A cache that keeps track of function descriptors associated with given 677 * functional interfaces. 678 */ 679 class DescriptorCache { 680 681 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<>(); 682 683 class FunctionDescriptor { 684 Symbol descSym; 685 686 FunctionDescriptor(Symbol descSym) { 687 this.descSym = descSym; 688 } 689 690 public Symbol getSymbol() { 691 return descSym; 692 } 693 694 public Type getType(Type site) { 695 site = removeWildcards(site); 696 if (site.isIntersection()) { 697 IntersectionClassType ict = (IntersectionClassType)site; 698 for (Type component : ict.getExplicitComponents()) { 699 if (!chk.checkValidGenericType(component)) { 700 //if the inferred functional interface type is not well-formed, 701 //or if it's not a subtype of the original target, issue an error 702 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site))); 703 } 704 } 705 } else { 706 if (!chk.checkValidGenericType(site)) { 707 //if the inferred functional interface type is not well-formed, 708 //or if it's not a subtype of the original target, issue an error 709 throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site))); 710 } 711 } 712 return memberType(site, descSym); 713 } 714 } 715 716 class Entry { 717 final FunctionDescriptor cachedDescRes; 718 final int prevMark; 719 720 public Entry(FunctionDescriptor cachedDescRes, 721 int prevMark) { 722 this.cachedDescRes = cachedDescRes; 723 this.prevMark = prevMark; 724 } 725 726 boolean matches(int mark) { 727 return this.prevMark == mark; 728 } 729 } 730 731 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError { 732 Entry e = _map.get(origin); 733 CompoundScope members = membersClosure(origin.type, false); 734 if (e == null || 735 !e.matches(members.getMark())) { 736 FunctionDescriptor descRes = findDescriptorInternal(origin, members); 737 _map.put(origin, new Entry(descRes, members.getMark())); 738 return descRes; 739 } 740 else { 741 return e.cachedDescRes; 742 } 743 } 744 745 /** 746 * Compute the function descriptor associated with a given functional interface 747 */ 748 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin, 749 CompoundScope membersCache) throws FunctionDescriptorLookupError { 750 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0) { 751 //t must be an interface 752 throw failure("not.a.functional.intf", origin); 753 } 754 755 final ListBuffer<Symbol> abstracts = new ListBuffer<>(); 756 for (Symbol sym : membersCache.getSymbols(new DescriptorFilter(origin))) { 757 Type mtype = memberType(origin.type, sym); 758 if (abstracts.isEmpty()) { 759 abstracts.append(sym); 760 } else if ((sym.name == abstracts.first().name && 761 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) { 762 if (!abstracts.stream().filter(msym -> msym.owner.isSubClass(sym.enclClass(), Types.this)) 763 .map(msym -> memberType(origin.type, msym)) 764 .anyMatch(abstractMType -> isSubSignature(abstractMType, mtype))) { 765 abstracts.append(sym); 766 } 767 } else { 768 //the target method(s) should be the only abstract members of t 769 throw failure("not.a.functional.intf.1", origin, 770 diags.fragment(Fragments.IncompatibleAbstracts(Kinds.kindName(origin), origin))); 771 } 772 } 773 if (abstracts.isEmpty()) { 774 //t must define a suitable non-generic method 775 throw failure("not.a.functional.intf.1", origin, 776 diags.fragment(Fragments.NoAbstracts(Kinds.kindName(origin), origin))); 777 } else if (abstracts.size() == 1) { 778 return new FunctionDescriptor(abstracts.first()); 779 } else { // size > 1 780 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList()); 781 if (descRes == null) { 782 //we can get here if the functional interface is ill-formed 783 ListBuffer<JCDiagnostic> descriptors = new ListBuffer<>(); 784 for (Symbol desc : abstracts) { 785 String key = desc.type.getThrownTypes().nonEmpty() ? 786 "descriptor.throws" : "descriptor"; 787 descriptors.append(diags.fragment(key, desc.name, 788 desc.type.getParameterTypes(), 789 desc.type.getReturnType(), 790 desc.type.getThrownTypes())); 791 } 792 JCDiagnostic msg = 793 diags.fragment(Fragments.IncompatibleDescsInFunctionalIntf(Kinds.kindName(origin), 794 origin)); 795 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors = 796 new JCDiagnostic.MultilineDiagnostic(msg, descriptors.toList()); 797 throw failure(incompatibleDescriptors); 798 } 799 return descRes; 800 } 801 } 802 803 /** 804 * Compute a synthetic type for the target descriptor given a list 805 * of override-equivalent methods in the functional interface type. 806 * The resulting method type is a method type that is override-equivalent 807 * and return-type substitutable with each method in the original list. 808 */ 809 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) { 810 return mergeAbstracts(methodSyms, origin.type, false) 811 .map(bestSoFar -> new FunctionDescriptor(bestSoFar.baseSymbol()) { 812 @Override 813 public Type getType(Type origin) { 814 Type mt = memberType(origin, getSymbol()); 815 return createMethodTypeWithThrown(mt, bestSoFar.type.getThrownTypes()); 816 } 817 }).orElse(null); 818 } 819 820 FunctionDescriptorLookupError failure(String msg, Object... args) { 821 return failure(diags.fragment(msg, args)); 822 } 823 824 FunctionDescriptorLookupError failure(JCDiagnostic diag) { 825 return new FunctionDescriptorLookupError().setMessage(diag); 826 } 827 } 828 829 private DescriptorCache descCache = new DescriptorCache(); 830 831 /** 832 * Find the method descriptor associated to this class symbol - if the 833 * symbol 'origin' is not a functional interface, an exception is thrown. 834 */ 835 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError { 836 return descCache.get(origin).getSymbol(); 837 } 838 839 /** 840 * Find the type of the method descriptor associated to this class symbol - 841 * if the symbol 'origin' is not a functional interface, an exception is thrown. 842 */ 843 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError { 844 return descCache.get(origin.tsym).getType(origin); 845 } 846 847 /** 848 * Is given type a functional interface? 849 */ 850 public boolean isFunctionalInterface(TypeSymbol tsym) { 851 try { 852 findDescriptorSymbol(tsym); 853 return true; 854 } catch (FunctionDescriptorLookupError ex) { 855 return false; 856 } 857 } 858 859 public boolean isFunctionalInterface(Type site) { 860 try { 861 findDescriptorType(site); 862 return true; 863 } catch (FunctionDescriptorLookupError ex) { 864 return false; 865 } 866 } 867 868 public Type removeWildcards(Type site) { 869 if (site.getTypeArguments().stream().anyMatch(t -> t.hasTag(WILDCARD))) { 870 //compute non-wildcard parameterization - JLS 9.9 871 List<Type> actuals = site.getTypeArguments(); 872 List<Type> formals = site.tsym.type.getTypeArguments(); 873 ListBuffer<Type> targs = new ListBuffer<>(); 874 for (Type formal : formals) { 875 Type actual = actuals.head; 876 Type bound = formal.getUpperBound(); 877 if (actuals.head.hasTag(WILDCARD)) { 878 WildcardType wt = (WildcardType)actual; 879 //check that bound does not contain other formals 880 if (bound.containsAny(formals)) { 881 targs.add(wt.type); 882 } else { 883 //compute new type-argument based on declared bound and wildcard bound 884 switch (wt.kind) { 885 case UNBOUND: 886 targs.add(bound); 887 break; 888 case EXTENDS: 889 targs.add(glb(bound, wt.type)); 890 break; 891 case SUPER: 892 targs.add(wt.type); 893 break; 894 default: 895 Assert.error("Cannot get here!"); 896 } 897 } 898 } else { 899 //not a wildcard - the new type argument remains unchanged 900 targs.add(actual); 901 } 902 actuals = actuals.tail; 903 } 904 return subst(site.tsym.type, formals, targs.toList()); 905 } else { 906 return site; 907 } 908 } 909 910 /** 911 * Create a symbol for a class that implements a given functional interface 912 * and overrides its functional descriptor. This routine is used for two 913 * main purposes: (i) checking well-formedness of a functional interface; 914 * (ii) perform functional interface bridge calculation. 915 */ 916 public ClassSymbol makeFunctionalInterfaceClass(Env<AttrContext> env, Name name, Type target, long cflags) { 917 if (target == null || target == syms.unknownType) { 918 return null; 919 } 920 Symbol descSym = findDescriptorSymbol(target.tsym); 921 Type descType = findDescriptorType(target); 922 ClassSymbol csym = new ClassSymbol(cflags, name, env.enclClass.sym.outermostClass()); 923 csym.completer = Completer.NULL_COMPLETER; 924 csym.members_field = WriteableScope.create(csym); 925 MethodSymbol instDescSym = new MethodSymbol(descSym.flags(), descSym.name, descType, csym); 926 csym.members_field.enter(instDescSym); 927 Type.ClassType ctype = new Type.ClassType(Type.noType, List.nil(), csym); 928 ctype.supertype_field = syms.objectType; 929 ctype.interfaces_field = target.isIntersection() ? 930 directSupertypes(target) : 931 List.of(target); 932 csym.type = ctype; 933 csym.sourcefile = ((ClassSymbol)csym.owner).sourcefile; 934 return csym; 935 } 936 937 /** 938 * Find the minimal set of methods that are overridden by the functional 939 * descriptor in 'origin'. All returned methods are assumed to have different 940 * erased signatures. 941 */ 942 public List<Symbol> functionalInterfaceBridges(TypeSymbol origin) { 943 Assert.check(isFunctionalInterface(origin)); 944 Symbol descSym = findDescriptorSymbol(origin); 945 CompoundScope members = membersClosure(origin.type, false); 946 ListBuffer<Symbol> overridden = new ListBuffer<>(); 947 outer: for (Symbol m2 : members.getSymbolsByName(descSym.name, bridgeFilter)) { 948 if (m2 == descSym) continue; 949 else if (descSym.overrides(m2, origin, Types.this, false)) { 950 for (Symbol m3 : overridden) { 951 if (isSameType(m3.erasure(Types.this), m2.erasure(Types.this)) || 952 (m3.overrides(m2, origin, Types.this, false) && 953 (pendingBridges((ClassSymbol)origin, m3.enclClass()) || 954 (((MethodSymbol)m2).binaryImplementation((ClassSymbol)m3.owner, Types.this) != null)))) { 955 continue outer; 956 } 957 } 958 overridden.add(m2); 959 } 960 } 961 return overridden.toList(); 962 } 963 //where 964 private Filter<Symbol> bridgeFilter = new Filter<Symbol>() { 965 public boolean accepts(Symbol t) { 966 return t.kind == MTH && 967 t.name != names.init && 968 t.name != names.clinit && 969 (t.flags() & SYNTHETIC) == 0; 970 } 971 }; 972 private boolean pendingBridges(ClassSymbol origin, TypeSymbol s) { 973 //a symbol will be completed from a classfile if (a) symbol has 974 //an associated file object with CLASS kind and (b) the symbol has 975 //not been entered 976 if (origin.classfile != null && 977 origin.classfile.getKind() == JavaFileObject.Kind.CLASS && 978 enter.getEnv(origin) == null) { 979 return false; 980 } 981 if (origin == s) { 982 return true; 983 } 984 for (Type t : interfaces(origin.type)) { 985 if (pendingBridges((ClassSymbol)t.tsym, s)) { 986 return true; 987 } 988 } 989 return false; 990 } 991 // </editor-fold> 992 993 /** 994 * Scope filter used to skip methods that should be ignored (such as methods 995 * overridden by j.l.Object) during function interface conversion interface check 996 */ 997 class DescriptorFilter implements Filter<Symbol> { 998 999 TypeSymbol origin; 1000 1001 DescriptorFilter(TypeSymbol origin) { 1002 this.origin = origin; 1003 } 1004 1005 @Override 1006 public boolean accepts(Symbol sym) { 1007 return sym.kind == MTH && 1008 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT && 1009 !overridesObjectMethod(origin, sym) && 1010 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0; 1011 } 1012 } 1013 1014 public boolean isValue(Type t) { 1015 return t != null && t.tsym != null && (t.tsym.flags_field & Flags.VALUE) != 0; 1016 } 1017 1018 public boolean isValueBased(Type t) { 1019 return allowValueBasedClasses && t != null && t.tsym != null && (t.tsym.flags() & Flags.VALUEBASED) != 0; 1020 } 1021 1022 // <editor-fold defaultstate="collapsed" desc="isSubtype"> 1023 /** 1024 * Is t an unchecked subtype of s? 1025 */ 1026 public boolean isSubtypeUnchecked(Type t, Type s) { 1027 return isSubtypeUnchecked(t, s, noWarnings); 1028 } 1029 /** 1030 * Is t an unchecked subtype of s? 1031 */ 1032 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) { 1033 boolean result = isSubtypeUncheckedInternal(t, s, true, warn); 1034 if (result) { 1035 checkUnsafeVarargsConversion(t, s, warn); 1036 } 1037 return result; 1038 } 1039 //where 1040 private boolean isSubtypeUncheckedInternal(Type t, Type s, boolean capture, Warner warn) { 1041 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) { 1042 if (((ArrayType)t).elemtype.isPrimitive()) { 1043 return isSameType(elemtype(t), elemtype(s)); 1044 } else { 1045 // if T.ref <: S, then T[] <: S[] 1046 Type es = elemtype(s); 1047 Type et = elemtype(t); 1048 if (isValue(et)) { 1049 et = et.referenceProjection(); 1050 if (isValue(es)) 1051 es = es.referenceProjection(); // V <: V, surely 1052 } 1053 if (!isSubtypeUncheckedInternal(et, es, false, warn)) 1054 return false; 1055 return true; 1056 } 1057 } else if (isSubtype(t, s, capture)) { 1058 return true; 1059 } else if (t.hasTag(TYPEVAR)) { 1060 return isSubtypeUncheckedInternal(t.getUpperBound(), s, false, warn); 1061 } else if (!s.isRaw()) { 1062 Type t2 = asSuper(t, s.tsym); 1063 if (t2 != null && t2.isRaw()) { 1064 if (isReifiable(s)) { 1065 warn.silentWarn(LintCategory.UNCHECKED); 1066 } else { 1067 warn.warn(LintCategory.UNCHECKED); 1068 } 1069 return true; 1070 } 1071 } 1072 return false; 1073 } 1074 1075 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) { 1076 if (!t.hasTag(ARRAY) || isReifiable(t)) { 1077 return; 1078 } 1079 ArrayType from = (ArrayType)t; 1080 boolean shouldWarn = false; 1081 switch (s.getTag()) { 1082 case ARRAY: 1083 ArrayType to = (ArrayType)s; 1084 shouldWarn = from.isVarargs() && 1085 !to.isVarargs() && 1086 !isReifiable(from); 1087 break; 1088 case CLASS: 1089 shouldWarn = from.isVarargs(); 1090 break; 1091 } 1092 if (shouldWarn) { 1093 warn.warn(LintCategory.VARARGS); 1094 } 1095 } 1096 1097 /** 1098 * Is t a subtype of s?<br> 1099 * (not defined for Method and ForAll types) 1100 */ 1101 final public boolean isSubtype(Type t, Type s) { 1102 return isSubtype(t, s, true); 1103 } 1104 final public boolean isSubtypeNoCapture(Type t, Type s) { 1105 return isSubtype(t, s, false); 1106 } 1107 public boolean isSubtype(Type t, Type s, boolean capture) { 1108 if (t.equalsIgnoreMetadata(s)) 1109 return true; 1110 if (s.isPartial()) 1111 return isSuperType(s, t); 1112 1113 if (s.isCompound()) { 1114 for (Type s2 : interfaces(s).prepend(supertype(s))) { 1115 if (!isSubtype(t, s2, capture)) 1116 return false; 1117 } 1118 return true; 1119 } 1120 1121 // Generally, if 's' is a lower-bounded type variable, recur on lower bound; but 1122 // for inference variables and intersections, we need to keep 's' 1123 // (see JLS 4.10.2 for intersections and 18.2.3 for inference vars) 1124 if (!t.hasTag(UNDETVAR) && !t.isCompound()) { 1125 // TODO: JDK-8039198, bounds checking sometimes passes in a wildcard as s 1126 Type lower = cvarLowerBound(wildLowerBound(s)); 1127 if (s != lower && !lower.hasTag(BOT)) 1128 return isSubtype(capture ? capture(t) : t, lower, false); 1129 } 1130 1131 return isSubtype.visit(capture ? capture(t) : t, s); 1132 } 1133 // where 1134 private TypeRelation isSubtype = new TypeRelation() 1135 { 1136 @Override 1137 public Boolean visitType(Type t, Type s) { 1138 switch (t.getTag()) { 1139 case BYTE: 1140 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag())); 1141 case CHAR: 1142 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag())); 1143 case SHORT: case INT: case LONG: 1144 case FLOAT: case DOUBLE: 1145 return t.getTag().isSubRangeOf(s.getTag()); 1146 case BOOLEAN: case VOID: 1147 return t.hasTag(s.getTag()); 1148 case TYPEVAR: 1149 return isSubtypeNoCapture(t.getUpperBound(), s); 1150 case BOT: 1151 return 1152 s.hasTag(BOT) || (s.hasTag(CLASS) && (!isValue(s) || isValueBased(s))) || 1153 s.hasTag(ARRAY) || s.hasTag(TYPEVAR); 1154 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495) 1155 case NONE: 1156 return false; 1157 default: 1158 throw new AssertionError("isSubtype " + t.getTag()); 1159 } 1160 } 1161 1162 private Set<TypePair> cache = new HashSet<>(); 1163 1164 private boolean containsTypeRecursive(Type t, Type s) { 1165 TypePair pair = new TypePair(t, s); 1166 if (cache.add(pair)) { 1167 try { 1168 return containsType(t.getTypeArguments(), 1169 s.getTypeArguments()); 1170 } finally { 1171 cache.remove(pair); 1172 } 1173 } else { 1174 return containsType(t.getTypeArguments(), 1175 rewriteSupers(s).getTypeArguments()); 1176 } 1177 } 1178 1179 private Type rewriteSupers(Type t) { 1180 if (!t.isParameterized()) 1181 return t; 1182 ListBuffer<Type> from = new ListBuffer<>(); 1183 ListBuffer<Type> to = new ListBuffer<>(); 1184 adaptSelf(t, from, to); 1185 if (from.isEmpty()) 1186 return t; 1187 ListBuffer<Type> rewrite = new ListBuffer<>(); 1188 boolean changed = false; 1189 for (Type orig : to.toList()) { 1190 Type s = rewriteSupers(orig); 1191 if (s.isSuperBound() && !s.isExtendsBound()) { 1192 s = new WildcardType(syms.objectType, 1193 BoundKind.UNBOUND, 1194 syms.boundClass, 1195 s.getMetadata()); 1196 changed = true; 1197 } else if (s != orig) { 1198 s = new WildcardType(wildUpperBound(s), 1199 BoundKind.EXTENDS, 1200 syms.boundClass, 1201 s.getMetadata()); 1202 changed = true; 1203 } 1204 rewrite.append(s); 1205 } 1206 if (changed) 1207 return subst(t.tsym.type, from.toList(), rewrite.toList()); 1208 else 1209 return t; 1210 } 1211 1212 @Override 1213 public Boolean visitClassType(ClassType t, Type s) { 1214 Type sup = asSuper(t, s.tsym); 1215 if (sup == null) return false; 1216 // If t is an intersection, sup might not be a class type 1217 if (!sup.hasTag(CLASS)) return isSubtypeNoCapture(sup, s); 1218 return sup.tsym == s.tsym 1219 // Check type variable containment 1220 && (!s.isParameterized() || containsTypeRecursive(s, sup)) 1221 && isSubtypeNoCapture(sup.getEnclosingType(), 1222 s.getEnclosingType()); 1223 } 1224 1225 @Override 1226 public Boolean visitArrayType(ArrayType t, Type s) { 1227 if (s.hasTag(ARRAY)) { 1228 if (t.elemtype.isPrimitive()) 1229 return isSameType(t.elemtype, elemtype(s)); 1230 else { 1231 // if T.ref <: S, then T[] <: S[] 1232 Type es = elemtype(s); 1233 Type et = elemtype(t); 1234 if (isValue(et)) { 1235 et = et.referenceProjection(); 1236 if (isValue(es)) 1237 es = es.referenceProjection(); // V <: V, surely 1238 } 1239 return isSubtypeNoCapture(et, es); 1240 } 1241 } 1242 1243 if (s.hasTag(CLASS)) { 1244 Name sname = s.tsym.getQualifiedName(); 1245 return sname == names.java_lang_Object 1246 || sname == names.java_lang_Cloneable 1247 || sname == names.java_io_Serializable 1248 || (injectTopInterfaceTypes && sname == names.java_lang_IdentityObject); 1249 } 1250 1251 return false; 1252 } 1253 1254 @Override 1255 public Boolean visitUndetVar(UndetVar t, Type s) { 1256 //todo: test against origin needed? or replace with substitution? 1257 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) { 1258 return true; 1259 } else if (s.hasTag(BOT)) { 1260 //if 's' is 'null' there's no instantiated type U for which 1261 //U <: s (but 'null' itself, which is not a valid type) 1262 return false; 1263 } 1264 1265 t.addBound(InferenceBound.UPPER, s, Types.this); 1266 return true; 1267 } 1268 1269 @Override 1270 public Boolean visitErrorType(ErrorType t, Type s) { 1271 return true; 1272 } 1273 }; 1274 1275 /** 1276 * Is t a subtype of every type in given list `ts'?<br> 1277 * (not defined for Method and ForAll types)<br> 1278 * Allows unchecked conversions. 1279 */ 1280 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) { 1281 for (List<Type> l = ts; l.nonEmpty(); l = l.tail) 1282 if (!isSubtypeUnchecked(t, l.head, warn)) 1283 return false; 1284 return true; 1285 } 1286 1287 /** 1288 * Are corresponding elements of ts subtypes of ss? If lists are 1289 * of different length, return false. 1290 */ 1291 public boolean isSubtypes(List<Type> ts, List<Type> ss) { 1292 while (ts.tail != null && ss.tail != null 1293 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ && 1294 isSubtype(ts.head, ss.head)) { 1295 ts = ts.tail; 1296 ss = ss.tail; 1297 } 1298 return ts.tail == null && ss.tail == null; 1299 /*inlined: ts.isEmpty() && ss.isEmpty();*/ 1300 } 1301 1302 /** 1303 * Are corresponding elements of ts subtypes of ss, allowing 1304 * unchecked conversions? If lists are of different length, 1305 * return false. 1306 **/ 1307 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) { 1308 while (ts.tail != null && ss.tail != null 1309 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ && 1310 isSubtypeUnchecked(ts.head, ss.head, warn)) { 1311 ts = ts.tail; 1312 ss = ss.tail; 1313 } 1314 return ts.tail == null && ss.tail == null; 1315 /*inlined: ts.isEmpty() && ss.isEmpty();*/ 1316 } 1317 // </editor-fold> 1318 1319 // <editor-fold defaultstate="collapsed" desc="isSuperType"> 1320 /** 1321 * Is t a supertype of s? 1322 */ 1323 public boolean isSuperType(Type t, Type s) { 1324 switch (t.getTag()) { 1325 case ERROR: 1326 return true; 1327 case UNDETVAR: { 1328 UndetVar undet = (UndetVar)t; 1329 if (t == s || 1330 undet.qtype == s || 1331 s.hasTag(ERROR) || 1332 s.hasTag(BOT)) { 1333 return true; 1334 } 1335 undet.addBound(InferenceBound.LOWER, s, this); 1336 return true; 1337 } 1338 default: 1339 return isSubtype(s, t); 1340 } 1341 } 1342 // </editor-fold> 1343 1344 // <editor-fold defaultstate="collapsed" desc="isSameType"> 1345 /** 1346 * Are corresponding elements of the lists the same type? If 1347 * lists are of different length, return false. 1348 */ 1349 public boolean isSameTypes(List<Type> ts, List<Type> ss) { 1350 while (ts.tail != null && ss.tail != null 1351 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ && 1352 isSameType(ts.head, ss.head)) { 1353 ts = ts.tail; 1354 ss = ss.tail; 1355 } 1356 return ts.tail == null && ss.tail == null; 1357 /*inlined: ts.isEmpty() && ss.isEmpty();*/ 1358 } 1359 1360 /** 1361 * A polymorphic signature method (JLS 15.12.3) is a method that 1362 * (i) is declared in the java.lang.invoke.MethodHandle/VarHandle classes; 1363 * (ii) takes a single variable arity parameter; 1364 * (iii) whose declared type is Object[]; 1365 * (iv) has any return type, Object signifying a polymorphic return type; and 1366 * (v) is native. 1367 */ 1368 public boolean isSignaturePolymorphic(MethodSymbol msym) { 1369 List<Type> argtypes = msym.type.getParameterTypes(); 1370 return (msym.flags_field & NATIVE) != 0 && 1371 (msym.owner == syms.methodHandleType.tsym || msym.owner == syms.varHandleType.tsym) && 1372 argtypes.length() == 1 && 1373 argtypes.head.hasTag(TypeTag.ARRAY) && 1374 ((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym; 1375 } 1376 1377 /** 1378 * Is t the same type as s? 1379 */ 1380 public boolean isSameType(Type t, Type s) { 1381 return isSameTypeVisitor.visit(t, s); 1382 } 1383 // where 1384 1385 /** 1386 * Type-equality relation - type variables are considered 1387 * equals if they share the same object identity. 1388 */ 1389 TypeRelation isSameTypeVisitor = new TypeRelation() { 1390 1391 public Boolean visitType(Type t, Type s) { 1392 if (t.equalsIgnoreMetadata(s)) 1393 return true; 1394 1395 if (s.isPartial()) 1396 return visit(s, t); 1397 1398 switch (t.getTag()) { 1399 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT: 1400 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE: 1401 return t.hasTag(s.getTag()); 1402 case TYPEVAR: { 1403 if (s.hasTag(TYPEVAR)) { 1404 //type-substitution does not preserve type-var types 1405 //check that type var symbols and bounds are indeed the same 1406 return t == s; 1407 } 1408 else { 1409 //special case for s == ? super X, where upper(s) = u 1410 //check that u == t, where u has been set by Type.withTypeVar 1411 return s.isSuperBound() && 1412 !s.isExtendsBound() && 1413 visit(t, wildUpperBound(s)); 1414 } 1415 } 1416 default: 1417 throw new AssertionError("isSameType " + t.getTag()); 1418 } 1419 } 1420 1421 @Override 1422 public Boolean visitWildcardType(WildcardType t, Type s) { 1423 if (!s.hasTag(WILDCARD)) { 1424 return false; 1425 } else { 1426 WildcardType t2 = (WildcardType)s; 1427 return (t.kind == t2.kind || (t.isExtendsBound() && s.isExtendsBound())) && 1428 isSameType(t.type, t2.type); 1429 } 1430 } 1431 1432 @Override 1433 public Boolean visitClassType(ClassType t, Type s) { 1434 if (t == s) 1435 return true; 1436 1437 if (s.isPartial()) 1438 return visit(s, t); 1439 1440 if (s.isSuperBound() && !s.isExtendsBound()) 1441 return visit(t, wildUpperBound(s)) && visit(t, wildLowerBound(s)); 1442 1443 if (t.isCompound() && s.isCompound()) { 1444 if (!visit(supertype(t), supertype(s))) 1445 return false; 1446 1447 Map<Symbol,Type> tMap = new HashMap<>(); 1448 for (Type ti : interfaces(t)) { 1449 if (tMap.containsKey(ti)) { 1450 throw new AssertionError("Malformed intersection"); 1451 } 1452 tMap.put(ti.tsym, ti); 1453 } 1454 for (Type si : interfaces(s)) { 1455 if (!tMap.containsKey(si.tsym)) 1456 return false; 1457 Type ti = tMap.remove(si.tsym); 1458 if (!visit(ti, si)) 1459 return false; 1460 } 1461 return tMap.isEmpty(); 1462 } 1463 return t.tsym == s.tsym 1464 && visit(t.getEnclosingType(), s.getEnclosingType()) 1465 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments()); 1466 } 1467 1468 @Override 1469 public Boolean visitArrayType(ArrayType t, Type s) { 1470 if (t == s) 1471 return true; 1472 1473 if (s.isPartial()) 1474 return visit(s, t); 1475 1476 return s.hasTag(ARRAY) 1477 && containsTypeEquivalent(t.elemtype, elemtype(s)); 1478 } 1479 1480 @Override 1481 public Boolean visitMethodType(MethodType t, Type s) { 1482 // isSameType for methods does not take thrown 1483 // exceptions into account! 1484 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType()); 1485 } 1486 1487 @Override 1488 public Boolean visitPackageType(PackageType t, Type s) { 1489 return t == s; 1490 } 1491 1492 @Override 1493 public Boolean visitForAll(ForAll t, Type s) { 1494 if (!s.hasTag(FORALL)) { 1495 return false; 1496 } 1497 1498 ForAll forAll = (ForAll)s; 1499 return hasSameBounds(t, forAll) 1500 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars)); 1501 } 1502 1503 @Override 1504 public Boolean visitUndetVar(UndetVar t, Type s) { 1505 if (s.hasTag(WILDCARD)) { 1506 // FIXME, this might be leftovers from before capture conversion 1507 return false; 1508 } 1509 1510 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) { 1511 return true; 1512 } 1513 1514 t.addBound(InferenceBound.EQ, s, Types.this); 1515 1516 return true; 1517 } 1518 1519 @Override 1520 public Boolean visitErrorType(ErrorType t, Type s) { 1521 return true; 1522 } 1523 }; 1524 1525 // </editor-fold> 1526 1527 // <editor-fold defaultstate="collapsed" desc="Contains Type"> 1528 public boolean containedBy(Type t, Type s) { 1529 switch (t.getTag()) { 1530 case UNDETVAR: 1531 if (s.hasTag(WILDCARD)) { 1532 UndetVar undetvar = (UndetVar)t; 1533 WildcardType wt = (WildcardType)s; 1534 switch(wt.kind) { 1535 case UNBOUND: 1536 break; 1537 case EXTENDS: { 1538 Type bound = wildUpperBound(s); 1539 undetvar.addBound(InferenceBound.UPPER, bound, this); 1540 break; 1541 } 1542 case SUPER: { 1543 Type bound = wildLowerBound(s); 1544 undetvar.addBound(InferenceBound.LOWER, bound, this); 1545 break; 1546 } 1547 } 1548 return true; 1549 } else { 1550 return isSameType(t, s); 1551 } 1552 case ERROR: 1553 return true; 1554 default: 1555 return containsType(s, t); 1556 } 1557 } 1558 1559 boolean containsType(List<Type> ts, List<Type> ss) { 1560 while (ts.nonEmpty() && ss.nonEmpty() 1561 && containsType(ts.head, ss.head)) { 1562 ts = ts.tail; 1563 ss = ss.tail; 1564 } 1565 return ts.isEmpty() && ss.isEmpty(); 1566 } 1567 1568 /** 1569 * Check if t contains s. 1570 * 1571 * <p>T contains S if: 1572 * 1573 * <p>{@code L(T) <: L(S) && U(S) <: U(T)} 1574 * 1575 * <p>This relation is only used by ClassType.isSubtype(), that 1576 * is, 1577 * 1578 * <p>{@code C<S> <: C<T> if T contains S.} 1579 * 1580 * <p>Because of F-bounds, this relation can lead to infinite 1581 * recursion. Thus we must somehow break that recursion. Notice 1582 * that containsType() is only called from ClassType.isSubtype(). 1583 * Since the arguments have already been checked against their 1584 * bounds, we know: 1585 * 1586 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)} 1587 * 1588 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)} 1589 * 1590 * @param t a type 1591 * @param s a type 1592 */ 1593 public boolean containsType(Type t, Type s) { 1594 return containsType.visit(t, s); 1595 } 1596 // where 1597 private TypeRelation containsType = new TypeRelation() { 1598 1599 public Boolean visitType(Type t, Type s) { 1600 if (s.isPartial()) 1601 return containedBy(s, t); 1602 else 1603 return isSameType(t, s); 1604 } 1605 1606 // void debugContainsType(WildcardType t, Type s) { 1607 // System.err.println(); 1608 // System.err.format(" does %s contain %s?%n", t, s); 1609 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n", 1610 // wildUpperBound(s), s, t, wildUpperBound(t), 1611 // t.isSuperBound() 1612 // || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t))); 1613 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n", 1614 // wildLowerBound(t), t, s, wildLowerBound(s), 1615 // t.isExtendsBound() 1616 // || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))); 1617 // System.err.println(); 1618 // } 1619 1620 @Override 1621 public Boolean visitWildcardType(WildcardType t, Type s) { 1622 if (s.isPartial()) 1623 return containedBy(s, t); 1624 else { 1625 // debugContainsType(t, s); 1626 1627 // ----------------------------------- Unspecified behavior ---------------- 1628 1629 /* If a value class V implements an interface I, then does "? extends I" contain V? 1630 It seems widening must be applied here to answer yes to compile some common code 1631 patterns. 1632 */ 1633 1634 // --------------------------------------------------------------------------- 1635 return isSameWildcard(t, s) 1636 || isCaptureOf(s, t) 1637 || ((t.isExtendsBound() || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))) && 1638 (t.isSuperBound() || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t)))); 1639 } 1640 } 1641 1642 @Override 1643 public Boolean visitUndetVar(UndetVar t, Type s) { 1644 if (!s.hasTag(WILDCARD)) { 1645 return isSameType(t, s); 1646 } else { 1647 return false; 1648 } 1649 } 1650 1651 @Override 1652 public Boolean visitErrorType(ErrorType t, Type s) { 1653 return true; 1654 } 1655 }; 1656 1657 public boolean isCaptureOf(Type s, WildcardType t) { 1658 if (!s.hasTag(TYPEVAR) || !((TypeVar)s).isCaptured()) 1659 return false; 1660 return isSameWildcard(t, ((CapturedType)s).wildcard); 1661 } 1662 1663 public boolean isSameWildcard(WildcardType t, Type s) { 1664 if (!s.hasTag(WILDCARD)) 1665 return false; 1666 WildcardType w = (WildcardType)s; 1667 return w.kind == t.kind && w.type == t.type; 1668 } 1669 1670 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) { 1671 while (ts.nonEmpty() && ss.nonEmpty() 1672 && containsTypeEquivalent(ts.head, ss.head)) { 1673 ts = ts.tail; 1674 ss = ss.tail; 1675 } 1676 return ts.isEmpty() && ss.isEmpty(); 1677 } 1678 // </editor-fold> 1679 1680 // <editor-fold defaultstate="collapsed" desc="isCastable"> 1681 public boolean isCastable(Type t, Type s) { 1682 return isCastable(t, s, noWarnings); 1683 } 1684 1685 /** 1686 * Is t is castable to s?<br> 1687 * s is assumed to be an erased type.<br> 1688 * (not defined for Method and ForAll types). 1689 */ 1690 public boolean isCastable(Type t, Type s, Warner warn) { 1691 if (t == s) 1692 return true; 1693 if (t.isPrimitive() != s.isPrimitive()) { 1694 t = skipTypeVars(t, false); 1695 return (isConvertible(t, s, warn) 1696 || (s.isPrimitive() && 1697 isSubtype(boxedClass(s).type, t))); 1698 } 1699 if (warn != warnStack.head) { 1700 try { 1701 warnStack = warnStack.prepend(warn); 1702 checkUnsafeVarargsConversion(t, s, warn); 1703 return isCastable.visit(t,s); 1704 } finally { 1705 warnStack = warnStack.tail; 1706 } 1707 } else { 1708 return isCastable.visit(t,s); 1709 } 1710 } 1711 // where 1712 private TypeRelation isCastable = new TypeRelation() { 1713 1714 public Boolean visitType(Type t, Type s) { 1715 if (s.hasTag(ERROR) || t.hasTag(NONE)) 1716 return true; 1717 1718 switch (t.getTag()) { 1719 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT: 1720 case DOUBLE: 1721 return s.isNumeric(); 1722 case BOOLEAN: 1723 return s.hasTag(BOOLEAN); 1724 case VOID: 1725 return false; 1726 case BOT: 1727 return isSubtype(t, s); 1728 default: 1729 throw new AssertionError(); 1730 } 1731 } 1732 1733 @Override 1734 public Boolean visitWildcardType(WildcardType t, Type s) { 1735 return isCastable(wildUpperBound(t), s, warnStack.head); 1736 } 1737 1738 @Override 1739 public Boolean visitClassType(ClassType t, Type s) { 1740 if (s.hasTag(ERROR) || (s.hasTag(BOT) && !isValue(t))) 1741 return true; 1742 1743 if (s.hasTag(TYPEVAR)) { 1744 if (isCastable(t, s.getUpperBound(), noWarnings)) { 1745 warnStack.head.warn(LintCategory.UNCHECKED); 1746 return true; 1747 } else { 1748 return false; 1749 } 1750 } 1751 1752 if (t.isCompound() || s.isCompound()) { 1753 return !t.isCompound() ? 1754 visitCompoundType((ClassType)s, t, true) : 1755 visitCompoundType(t, s, false); 1756 } 1757 1758 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) { 1759 if (isValue(t)) { 1760 // (s) Value ? == (s) Value.ref 1761 t = t.referenceProjection(); 1762 } 1763 if (isValue(s)) { 1764 // (Value) t ? == (Value.ref) t 1765 s = s.referenceProjection(); 1766 } 1767 boolean upcast; 1768 if ((upcast = isSubtype(erasure(t), erasure(s))) 1769 || isSubtype(erasure(s), erasure(t))) { 1770 if (!upcast && s.hasTag(ARRAY)) { 1771 if (!isReifiable(s)) 1772 warnStack.head.warn(LintCategory.UNCHECKED); 1773 return true; 1774 } else if (s.isRaw()) { 1775 return true; 1776 } else if (t.isRaw()) { 1777 if (!isUnbounded(s)) 1778 warnStack.head.warn(LintCategory.UNCHECKED); 1779 return true; 1780 } 1781 // Assume |a| <: |b| 1782 final Type a = upcast ? t : s; 1783 final Type b = upcast ? s : t; 1784 final boolean HIGH = true; 1785 final boolean LOW = false; 1786 final boolean DONT_REWRITE_TYPEVARS = false; 1787 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS); 1788 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS); 1789 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS); 1790 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS); 1791 Type lowSub = asSub(bLow, aLow.tsym); 1792 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym); 1793 if (highSub == null) { 1794 final boolean REWRITE_TYPEVARS = true; 1795 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS); 1796 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS); 1797 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS); 1798 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS); 1799 lowSub = asSub(bLow, aLow.tsym); 1800 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym); 1801 } 1802 if (highSub != null) { 1803 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) { 1804 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym); 1805 } 1806 if (!disjointTypes(aHigh.allparams(), highSub.allparams()) 1807 && !disjointTypes(aHigh.allparams(), lowSub.allparams()) 1808 && !disjointTypes(aLow.allparams(), highSub.allparams()) 1809 && !disjointTypes(aLow.allparams(), lowSub.allparams())) { 1810 if (upcast ? giveWarning(a, b) : 1811 giveWarning(b, a)) 1812 warnStack.head.warn(LintCategory.UNCHECKED); 1813 return true; 1814 } 1815 } 1816 if (isReifiable(s)) 1817 return isSubtypeUnchecked(a, b); 1818 else 1819 return isSubtypeUnchecked(a, b, warnStack.head); 1820 } 1821 1822 // Sidecast 1823 if (s.hasTag(CLASS)) { 1824 if ((s.tsym.flags() & INTERFACE) != 0) { 1825 return ((t.tsym.flags() & FINAL) == 0) 1826 ? sideCast(t, s, warnStack.head) 1827 : sideCastFinal(t, s, warnStack.head); 1828 } else if ((t.tsym.flags() & INTERFACE) != 0) { 1829 return ((s.tsym.flags() & FINAL) == 0) 1830 ? sideCast(t, s, warnStack.head) 1831 : sideCastFinal(t, s, warnStack.head); 1832 } else { 1833 // unrelated class types 1834 return false; 1835 } 1836 } 1837 } 1838 return false; 1839 } 1840 1841 boolean visitCompoundType(ClassType ct, Type s, boolean reverse) { 1842 Warner warn = noWarnings; 1843 for (Type c : directSupertypes(ct)) { 1844 warn.clear(); 1845 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn)) 1846 return false; 1847 } 1848 if (warn.hasLint(LintCategory.UNCHECKED)) 1849 warnStack.head.warn(LintCategory.UNCHECKED); 1850 return true; 1851 } 1852 1853 @Override 1854 public Boolean visitArrayType(ArrayType t, Type s) { 1855 switch (s.getTag()) { 1856 case ERROR: 1857 case BOT: 1858 return true; 1859 case TYPEVAR: 1860 if (isCastable(s, t, noWarnings)) { 1861 warnStack.head.warn(LintCategory.UNCHECKED); 1862 return true; 1863 } else { 1864 return false; 1865 } 1866 case CLASS: 1867 return isSubtype(t, s); 1868 case ARRAY: 1869 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) { 1870 return elemtype(t).hasTag(elemtype(s).getTag()); 1871 } else { 1872 Type et = elemtype(t); 1873 Type es = elemtype(s); 1874 if (!visit(et, es)) 1875 return false; 1876 return true; 1877 } 1878 default: 1879 return false; 1880 } 1881 } 1882 1883 @Override 1884 public Boolean visitTypeVar(TypeVar t, Type s) { 1885 switch (s.getTag()) { 1886 case ERROR: 1887 case BOT: 1888 return true; 1889 case TYPEVAR: 1890 if (isSubtype(t, s)) { 1891 return true; 1892 } else if (isCastable(t.getUpperBound(), s, noWarnings)) { 1893 warnStack.head.warn(LintCategory.UNCHECKED); 1894 return true; 1895 } else { 1896 return false; 1897 } 1898 default: 1899 return isCastable(t.getUpperBound(), s, warnStack.head); 1900 } 1901 } 1902 1903 @Override 1904 public Boolean visitErrorType(ErrorType t, Type s) { 1905 return true; 1906 } 1907 }; 1908 // </editor-fold> 1909 1910 // <editor-fold defaultstate="collapsed" desc="disjointTypes"> 1911 public boolean disjointTypes(List<Type> ts, List<Type> ss) { 1912 while (ts.tail != null && ss.tail != null) { 1913 if (disjointType(ts.head, ss.head)) return true; 1914 ts = ts.tail; 1915 ss = ss.tail; 1916 } 1917 return false; 1918 } 1919 1920 /** 1921 * Two types or wildcards are considered disjoint if it can be 1922 * proven that no type can be contained in both. It is 1923 * conservative in that it is allowed to say that two types are 1924 * not disjoint, even though they actually are. 1925 * 1926 * The type {@code C<X>} is castable to {@code C<Y>} exactly if 1927 * {@code X} and {@code Y} are not disjoint. 1928 */ 1929 public boolean disjointType(Type t, Type s) { 1930 return disjointType.visit(t, s); 1931 } 1932 // where 1933 private TypeRelation disjointType = new TypeRelation() { 1934 1935 private Set<TypePair> cache = new HashSet<>(); 1936 1937 @Override 1938 public Boolean visitType(Type t, Type s) { 1939 if (s.hasTag(WILDCARD)) 1940 return visit(s, t); 1941 else 1942 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t); 1943 } 1944 1945 private boolean isCastableRecursive(Type t, Type s) { 1946 TypePair pair = new TypePair(t, s); 1947 if (cache.add(pair)) { 1948 try { 1949 return Types.this.isCastable(t, s); 1950 } finally { 1951 cache.remove(pair); 1952 } 1953 } else { 1954 return true; 1955 } 1956 } 1957 1958 private boolean notSoftSubtypeRecursive(Type t, Type s) { 1959 TypePair pair = new TypePair(t, s); 1960 if (cache.add(pair)) { 1961 try { 1962 return Types.this.notSoftSubtype(t, s); 1963 } finally { 1964 cache.remove(pair); 1965 } 1966 } else { 1967 return false; 1968 } 1969 } 1970 1971 @Override 1972 public Boolean visitWildcardType(WildcardType t, Type s) { 1973 if (t.isUnbound()) 1974 return false; 1975 1976 if (!s.hasTag(WILDCARD)) { 1977 if (t.isExtendsBound()) 1978 return notSoftSubtypeRecursive(s, t.type); 1979 else 1980 return notSoftSubtypeRecursive(t.type, s); 1981 } 1982 1983 if (s.isUnbound()) 1984 return false; 1985 1986 if (t.isExtendsBound()) { 1987 if (s.isExtendsBound()) 1988 return !isCastableRecursive(t.type, wildUpperBound(s)); 1989 else if (s.isSuperBound()) 1990 return notSoftSubtypeRecursive(wildLowerBound(s), t.type); 1991 } else if (t.isSuperBound()) { 1992 if (s.isExtendsBound()) 1993 return notSoftSubtypeRecursive(t.type, wildUpperBound(s)); 1994 } 1995 return false; 1996 } 1997 }; 1998 // </editor-fold> 1999 2000 // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds"> 2001 public List<Type> cvarLowerBounds(List<Type> ts) { 2002 return ts.map(cvarLowerBoundMapping); 2003 } 2004 private final TypeMapping<Void> cvarLowerBoundMapping = new TypeMapping<Void>() { 2005 @Override 2006 public Type visitCapturedType(CapturedType t, Void _unused) { 2007 return cvarLowerBound(t); 2008 } 2009 }; 2010 // </editor-fold> 2011 2012 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype"> 2013 /** 2014 * This relation answers the question: is impossible that 2015 * something of type `t' can be a subtype of `s'? This is 2016 * different from the question "is `t' not a subtype of `s'?" 2017 * when type variables are involved: Integer is not a subtype of T 2018 * where {@code <T extends Number>} but it is not true that Integer cannot 2019 * possibly be a subtype of T. 2020 */ 2021 public boolean notSoftSubtype(Type t, Type s) { 2022 if (t == s) return false; 2023 if (t.hasTag(TYPEVAR)) { 2024 TypeVar tv = (TypeVar) t; 2025 return !isCastable(tv.getUpperBound(), 2026 relaxBound(s), 2027 noWarnings); 2028 } 2029 if (!s.hasTag(WILDCARD)) 2030 s = cvarUpperBound(s); 2031 2032 return !isSubtype(t, relaxBound(s)); 2033 } 2034 2035 private Type relaxBound(Type t) { 2036 return (t.hasTag(TYPEVAR)) ? 2037 rewriteQuantifiers(skipTypeVars(t, false), true, true) : 2038 t; 2039 } 2040 // </editor-fold> 2041 2042 // <editor-fold defaultstate="collapsed" desc="isReifiable"> 2043 public boolean isReifiable(Type t) { 2044 return isReifiable.visit(t); 2045 } 2046 // where 2047 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() { 2048 2049 public Boolean visitType(Type t, Void ignored) { 2050 return true; 2051 } 2052 2053 @Override 2054 public Boolean visitClassType(ClassType t, Void ignored) { 2055 if (t.isCompound()) 2056 return false; 2057 else { 2058 if (!t.isParameterized()) 2059 return true; 2060 2061 for (Type param : t.allparams()) { 2062 if (!param.isUnbound()) 2063 return false; 2064 } 2065 return true; 2066 } 2067 } 2068 2069 @Override 2070 public Boolean visitArrayType(ArrayType t, Void ignored) { 2071 return visit(t.elemtype); 2072 } 2073 2074 @Override 2075 public Boolean visitTypeVar(TypeVar t, Void ignored) { 2076 return false; 2077 } 2078 }; 2079 // </editor-fold> 2080 2081 // <editor-fold defaultstate="collapsed" desc="Array Utils"> 2082 public boolean isArray(Type t) { 2083 while (t.hasTag(WILDCARD)) 2084 t = wildUpperBound(t); 2085 return t.hasTag(ARRAY); 2086 } 2087 2088 /** 2089 * The element type of an array. 2090 */ 2091 public Type elemtype(Type t) { 2092 switch (t.getTag()) { 2093 case WILDCARD: 2094 return elemtype(wildUpperBound(t)); 2095 case ARRAY: 2096 return ((ArrayType)t).elemtype; 2097 case FORALL: 2098 return elemtype(((ForAll)t).qtype); 2099 case ERROR: 2100 return t; 2101 default: 2102 return null; 2103 } 2104 } 2105 2106 public Type elemtypeOrType(Type t) { 2107 Type elemtype = elemtype(t); 2108 return elemtype != null ? 2109 elemtype : 2110 t; 2111 } 2112 2113 /** 2114 * Mapping to take element type of an arraytype 2115 */ 2116 private TypeMapping<Void> elemTypeFun = new TypeMapping<Void>() { 2117 @Override 2118 public Type visitArrayType(ArrayType t, Void _unused) { 2119 return t.elemtype; 2120 } 2121 2122 @Override 2123 public Type visitTypeVar(TypeVar t, Void _unused) { 2124 return visit(skipTypeVars(t, false)); 2125 } 2126 }; 2127 2128 /** 2129 * The number of dimensions of an array type. 2130 */ 2131 public int dimensions(Type t) { 2132 int result = 0; 2133 while (t.hasTag(ARRAY)) { 2134 result++; 2135 t = elemtype(t); 2136 } 2137 return result; 2138 } 2139 2140 /** 2141 * Returns an ArrayType with the component type t 2142 * 2143 * @param t The component type of the ArrayType 2144 * @return the ArrayType for the given component 2145 */ 2146 public ArrayType makeArrayType(Type t) { 2147 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) { 2148 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString()); 2149 } 2150 return new ArrayType(t, syms.arrayClass); 2151 } 2152 // </editor-fold> 2153 2154 // <editor-fold defaultstate="collapsed" desc="asSuper"> 2155 /** 2156 * Return the (most specific) base type of t that starts with the 2157 * given symbol. If none exists, return null. 2158 * 2159 * Caveat Emptor: Since javac represents the class of all arrays with a singleton 2160 * symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant, 2161 * this method could yield surprising answers when invoked on arrays. For example when 2162 * invoked with t being byte [] and sym being t.sym itself, asSuper would answer null. 2163 * 2164 * @param t a type 2165 * @param sym a symbol 2166 */ 2167 public Type asSuper(Type t, Symbol sym) { 2168 /* Some examples: 2169 * 2170 * (Enum<E>, Comparable) => Comparable<E> 2171 * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind> 2172 * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree 2173 * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) => 2174 * Iterable<capture#160 of ? extends c.s.s.d.DocTree> 2175 */ 2176 if (sym.type == syms.objectType) { //optimization 2177 if (!isValue(t)) 2178 return syms.objectType; 2179 } 2180 return asSuper.visit(t, sym); 2181 } 2182 // where 2183 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() { 2184 2185 public Type visitType(Type t, Symbol sym) { 2186 return null; 2187 } 2188 2189 @Override 2190 public Type visitClassType(ClassType t, Symbol sym) { 2191 if (t.tsym == sym) 2192 return t; 2193 2194 // No man may be an island, but the bell tolls for a value. 2195 if (isValue(t)) 2196 return null; 2197 2198 Type st = supertype(t); 2199 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) { 2200 Type x = asSuper(st, sym); 2201 if (x != null) 2202 return x; 2203 } 2204 if ((sym.flags() & INTERFACE) != 0) { 2205 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) { 2206 if (!l.head.hasTag(ERROR)) { 2207 Type x = asSuper(l.head, sym); 2208 if (x != null) 2209 return x; 2210 } 2211 } 2212 } 2213 return null; 2214 } 2215 2216 @Override 2217 public Type visitArrayType(ArrayType t, Symbol sym) { 2218 return isSubtype(t, sym.type) ? sym.type : null; 2219 } 2220 2221 @Override 2222 public Type visitTypeVar(TypeVar t, Symbol sym) { 2223 if (t.tsym == sym) 2224 return t; 2225 else 2226 return asSuper(t.getUpperBound(), sym); 2227 } 2228 2229 @Override 2230 public Type visitErrorType(ErrorType t, Symbol sym) { 2231 return t; 2232 } 2233 }; 2234 2235 /** 2236 * Return the base type of t or any of its outer types that starts 2237 * with the given symbol. If none exists, return null. 2238 * 2239 * @param t a type 2240 * @param sym a symbol 2241 */ 2242 public Type asOuterSuper(Type t, Symbol sym) { 2243 switch (t.getTag()) { 2244 case CLASS: 2245 do { 2246 Type s = asSuper(t, sym); 2247 if (s != null) return s; 2248 t = t.getEnclosingType(); 2249 } while (t.hasTag(CLASS)); 2250 return null; 2251 case ARRAY: 2252 return isSubtype(t, sym.type) ? sym.type : null; 2253 case TYPEVAR: 2254 return asSuper(t, sym); 2255 case ERROR: 2256 return t; 2257 default: 2258 return null; 2259 } 2260 } 2261 2262 /** 2263 * Return the base type of t or any of its enclosing types that 2264 * starts with the given symbol. If none exists, return null. 2265 * 2266 * @param t a type 2267 * @param sym a symbol 2268 */ 2269 public Type asEnclosingSuper(Type t, Symbol sym) { 2270 switch (t.getTag()) { 2271 case CLASS: 2272 do { 2273 Type s = asSuper(t, sym); 2274 if (s != null) return s; 2275 Type outer = t.getEnclosingType(); 2276 t = (outer.hasTag(CLASS)) ? outer : 2277 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type : 2278 Type.noType; 2279 } while (t.hasTag(CLASS)); 2280 return null; 2281 case ARRAY: 2282 return isSubtype(t, sym.type) ? sym.type : null; 2283 case TYPEVAR: 2284 return asSuper(t, sym); 2285 case ERROR: 2286 return t; 2287 default: 2288 return null; 2289 } 2290 } 2291 // </editor-fold> 2292 2293 // <editor-fold defaultstate="collapsed" desc="memberType"> 2294 /** 2295 * The type of given symbol, seen as a member of t. 2296 * 2297 * @param t a type 2298 * @param sym a symbol 2299 */ 2300 public Type memberType(Type t, Symbol sym) { 2301 2302 if ((sym.flags() & STATIC) != 0) 2303 return sym.type; 2304 2305 /* If any inline types are involved, switch over to the reference universe, 2306 where the hierarchy is navigable. V and V.ref have identical membership 2307 with no bridging needs. 2308 */ 2309 if (t.isValue()) 2310 t = t.referenceProjection(); 2311 2312 if (sym.owner.isValue()) 2313 sym = sym.referenceProjection(); 2314 2315 return memberType.visit(t, sym); 2316 } 2317 // where 2318 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() { 2319 2320 public Type visitType(Type t, Symbol sym) { 2321 return sym.type; 2322 } 2323 2324 @Override 2325 public Type visitWildcardType(WildcardType t, Symbol sym) { 2326 return memberType(wildUpperBound(t), sym); 2327 } 2328 2329 @Override 2330 public Type visitClassType(ClassType t, Symbol sym) { 2331 Symbol owner = sym.owner; 2332 long flags = sym.flags(); 2333 if (((flags & STATIC) == 0) && owner.type.isParameterized()) { 2334 Type base = asOuterSuper(t, owner); 2335 //if t is an intersection type T = CT & I1 & I2 ... & In 2336 //its supertypes CT, I1, ... In might contain wildcards 2337 //so we need to go through capture conversion 2338 base = t.isCompound() ? capture(base) : base; 2339 if (base != null) { 2340 List<Type> ownerParams = owner.type.allparams(); 2341 List<Type> baseParams = base.allparams(); 2342 if (ownerParams.nonEmpty()) { 2343 if (baseParams.isEmpty()) { 2344 // then base is a raw type 2345 return erasure(sym.type); 2346 } else { 2347 return subst(sym.type, ownerParams, baseParams); 2348 } 2349 } 2350 } 2351 } 2352 return sym.type; 2353 } 2354 2355 @Override 2356 public Type visitTypeVar(TypeVar t, Symbol sym) { 2357 return memberType(t.getUpperBound(), sym); 2358 } 2359 2360 @Override 2361 public Type visitErrorType(ErrorType t, Symbol sym) { 2362 return t; 2363 } 2364 }; 2365 // </editor-fold> 2366 2367 // <editor-fold defaultstate="collapsed" desc="isAssignable"> 2368 public boolean isAssignable(Type t, Type s) { 2369 return isAssignable(t, s, noWarnings); 2370 } 2371 2372 /** 2373 * Is t assignable to s?<br> 2374 * Equivalent to subtype except for constant values and raw 2375 * types.<br> 2376 * (not defined for Method and ForAll types) 2377 */ 2378 public boolean isAssignable(Type t, Type s, Warner warn) { 2379 if (t.hasTag(ERROR)) 2380 return true; 2381 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) { 2382 int value = ((Number)t.constValue()).intValue(); 2383 switch (s.getTag()) { 2384 case BYTE: 2385 case CHAR: 2386 case SHORT: 2387 case INT: 2388 if (s.getTag().checkRange(value)) 2389 return true; 2390 break; 2391 case CLASS: 2392 switch (unboxedType(s).getTag()) { 2393 case BYTE: 2394 case CHAR: 2395 case SHORT: 2396 return isAssignable(t, unboxedType(s), warn); 2397 } 2398 break; 2399 } 2400 } 2401 return isConvertible(t, s, warn); 2402 } 2403 // </editor-fold> 2404 2405 // <editor-fold defaultstate="collapsed" desc="erasure"> 2406 /** 2407 * The erasure of t {@code |t|} -- the type that results when all 2408 * type parameters in t are deleted. 2409 */ 2410 public Type erasure(Type t) { 2411 return eraseNotNeeded(t) ? t : erasure(t, false); 2412 } 2413 //where 2414 private boolean eraseNotNeeded(Type t) { 2415 // We don't want to erase primitive types and String type as that 2416 // operation is idempotent. Also, erasing these could result in loss 2417 // of information such as constant values attached to such types. 2418 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym); 2419 } 2420 2421 private Type erasure(Type t, boolean recurse) { 2422 if (t.isPrimitive()) { 2423 return t; /* fast special case */ 2424 } else { 2425 Type out = erasure.visit(t, recurse); 2426 return out; 2427 } 2428 } 2429 // where 2430 private TypeMapping<Boolean> erasure = new StructuralTypeMapping<Boolean>() { 2431 private Type combineMetadata(final Type s, 2432 final Type t) { 2433 if (t.getMetadata() != TypeMetadata.EMPTY) { 2434 switch (s.getKind()) { 2435 case OTHER: 2436 case UNION: 2437 case INTERSECTION: 2438 case PACKAGE: 2439 case EXECUTABLE: 2440 case NONE: 2441 case VOID: 2442 case ERROR: 2443 return s; 2444 default: return s.cloneWithMetadata(s.getMetadata().without(Kind.ANNOTATIONS)); 2445 } 2446 } else { 2447 return s; 2448 } 2449 } 2450 2451 public Type visitType(Type t, Boolean recurse) { 2452 if (t.isPrimitive()) 2453 return t; /*fast special case*/ 2454 else { 2455 //other cases already handled 2456 return combineMetadata(t, t); 2457 } 2458 } 2459 2460 @Override 2461 public Type visitWildcardType(WildcardType t, Boolean recurse) { 2462 Type erased = erasure(wildUpperBound(t), recurse); 2463 return combineMetadata(erased, t); 2464 } 2465 2466 @Override 2467 public Type visitClassType(ClassType t, Boolean recurse) { 2468 Type erased = t.tsym.erasure(Types.this); 2469 if (recurse) { 2470 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym, 2471 t.getMetadata().without(Kind.ANNOTATIONS)); 2472 return erased; 2473 } else { 2474 return combineMetadata(erased, t); 2475 } 2476 } 2477 2478 @Override 2479 public Type visitTypeVar(TypeVar t, Boolean recurse) { 2480 Type erased = erasure(t.getUpperBound(), recurse); 2481 return combineMetadata(erased, t); 2482 } 2483 }; 2484 2485 public List<Type> erasure(List<Type> ts) { 2486 return erasure.visit(ts, false); 2487 } 2488 2489 public Type erasureRecursive(Type t) { 2490 return erasure(t, true); 2491 } 2492 2493 public List<Type> erasureRecursive(List<Type> ts) { 2494 return erasure.visit(ts, true); 2495 } 2496 // </editor-fold> 2497 2498 // <editor-fold defaultstate="collapsed" desc="makeIntersectionType"> 2499 /** 2500 * Make an intersection type from non-empty list of types. The list should be ordered according to 2501 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion. 2502 * Hence, this version of makeIntersectionType may not be called during a classfile read. 2503 * 2504 * @param bounds the types from which the intersection type is formed 2505 */ 2506 public IntersectionClassType makeIntersectionType(List<Type> bounds) { 2507 return makeIntersectionType(bounds, bounds.head.tsym.isInterface()); 2508 } 2509 2510 /** 2511 * Make an intersection type from non-empty list of types. The list should be ordered according to 2512 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as 2513 * an extra parameter indicates as to whether all bounds are interfaces - in which case the 2514 * supertype is implicitly assumed to be 'Object'. 2515 * 2516 * @param bounds the types from which the intersection type is formed 2517 * @param allInterfaces are all bounds interface types? 2518 */ 2519 public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) { 2520 Assert.check(bounds.nonEmpty()); 2521 Type firstExplicitBound = bounds.head; 2522 if (allInterfaces) { 2523 bounds = bounds.prepend(syms.objectType); 2524 } 2525 long flags = ABSTRACT | PUBLIC | SYNTHETIC | COMPOUND | ACYCLIC; 2526 if (isValue(bounds.head)) 2527 flags |= VALUE; 2528 ClassSymbol bc = 2529 new ClassSymbol(flags, 2530 Type.moreInfo 2531 ? names.fromString(bounds.toString()) 2532 : names.empty, 2533 null, 2534 syms.noSymbol); 2535 IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces); 2536 bc.type = intersectionType; 2537 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ? 2538 syms.objectType : // error condition, recover 2539 erasure(firstExplicitBound); 2540 bc.members_field = WriteableScope.create(bc); 2541 return intersectionType; 2542 } 2543 // </editor-fold> 2544 2545 // <editor-fold defaultstate="collapsed" desc="supertype"> 2546 public Type supertype(Type t) { 2547 return supertype.visit(t); 2548 } 2549 // where 2550 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() { 2551 2552 public Type visitType(Type t, Void ignored) { 2553 // A note on wildcards: there is no good way to 2554 // determine a supertype for a super bounded wildcard. 2555 return Type.noType; 2556 } 2557 2558 @Override 2559 public Type visitClassType(ClassType t, Void ignored) { 2560 if (t.supertype_field == null) { 2561 Type supertype = ((ClassSymbol)t.tsym).getSuperclass(); 2562 // An interface has no superclass; its supertype is Object. 2563 if (t.isInterface()) 2564 supertype = ((ClassType)t.tsym.type).supertype_field; 2565 if (t.supertype_field == null) { 2566 List<Type> actuals = classBound(t).allparams(); 2567 List<Type> formals = t.tsym.type.allparams(); 2568 if (t.hasErasedSupertypes()) { 2569 t.supertype_field = erasureRecursive(supertype); 2570 } else if (formals.nonEmpty()) { 2571 t.supertype_field = subst(supertype, formals, actuals); 2572 } 2573 else { 2574 t.supertype_field = supertype; 2575 } 2576 } 2577 } 2578 return t.supertype_field; 2579 } 2580 2581 /** 2582 * The supertype is always a class type. If the type 2583 * variable's bounds start with a class type, this is also 2584 * the supertype. Otherwise, the supertype is 2585 * java.lang.Object. 2586 */ 2587 @Override 2588 public Type visitTypeVar(TypeVar t, Void ignored) { 2589 if (t.getUpperBound().hasTag(TYPEVAR) || 2590 (!t.getUpperBound().isCompound() && !t.getUpperBound().isInterface())) { 2591 return t.getUpperBound(); 2592 } else { 2593 return supertype(t.getUpperBound()); 2594 } 2595 } 2596 2597 @Override 2598 public Type visitArrayType(ArrayType t, Void ignored) { 2599 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType)) 2600 return arraySuperType(); 2601 else 2602 return new ArrayType(supertype(t.elemtype), t.tsym); 2603 } 2604 2605 @Override 2606 public Type visitErrorType(ErrorType t, Void ignored) { 2607 return Type.noType; 2608 } 2609 }; 2610 // </editor-fold> 2611 2612 // <editor-fold defaultstate="collapsed" desc="interfaces"> 2613 /** 2614 * Return the interfaces implemented by this class. 2615 */ 2616 public List<Type> interfaces(Type t) { 2617 return interfaces.visit(t); 2618 } 2619 // where 2620 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() { 2621 2622 public List<Type> visitType(Type t, Void ignored) { 2623 return List.nil(); 2624 } 2625 2626 @Override 2627 public List<Type> visitClassType(ClassType t, Void ignored) { 2628 if (t.interfaces_field == null) { 2629 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces(); 2630 if (t.interfaces_field == null) { 2631 // If t.interfaces_field is null, then t must 2632 // be a parameterized type (not to be confused 2633 // with a generic type declaration). 2634 // Terminology: 2635 // Parameterized type: List<String> 2636 // Generic type declaration: class List<E> { ... } 2637 // So t corresponds to List<String> and 2638 // t.tsym.type corresponds to List<E>. 2639 // The reason t must be parameterized type is 2640 // that completion will happen as a side 2641 // effect of calling 2642 // ClassSymbol.getInterfaces. Since 2643 // t.interfaces_field is null after 2644 // completion, we can assume that t is not the 2645 // type of a class/interface declaration. 2646 Assert.check(t != t.tsym.type, t); 2647 List<Type> actuals = t.allparams(); 2648 List<Type> formals = t.tsym.type.allparams(); 2649 if (t.hasErasedSupertypes()) { 2650 t.interfaces_field = erasureRecursive(interfaces); 2651 } else if (formals.nonEmpty()) { 2652 t.interfaces_field = subst(interfaces, formals, actuals); 2653 } 2654 else { 2655 t.interfaces_field = interfaces; 2656 } 2657 } 2658 } 2659 return t.interfaces_field; 2660 } 2661 2662 @Override 2663 public List<Type> visitTypeVar(TypeVar t, Void ignored) { 2664 if (t.getUpperBound().isCompound()) 2665 return interfaces(t.getUpperBound()); 2666 2667 if (t.getUpperBound().isInterface()) 2668 return List.of(t.getUpperBound()); 2669 2670 return List.nil(); 2671 } 2672 }; 2673 2674 public List<Type> directSupertypes(Type t) { 2675 return directSupertypes.visit(t); 2676 } 2677 // where 2678 private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() { 2679 2680 public List<Type> visitType(final Type type, final Void ignored) { 2681 if (!type.isIntersection()) { 2682 final Type sup = supertype(type); 2683 return (sup == Type.noType || sup == type || sup == null) 2684 ? interfaces(type) 2685 : interfaces(type).prepend(sup); 2686 } else { 2687 return ((IntersectionClassType)type).getExplicitComponents(); 2688 } 2689 } 2690 }; 2691 2692 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) { 2693 for (Type i2 : interfaces(origin.type)) { 2694 if (isym == i2.tsym) return true; 2695 } 2696 return false; 2697 } 2698 // </editor-fold> 2699 2700 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw"> 2701 Map<Type,Boolean> isDerivedRawCache = new HashMap<>(); 2702 2703 public boolean isDerivedRaw(Type t) { 2704 Boolean result = isDerivedRawCache.get(t); 2705 if (result == null) { 2706 result = isDerivedRawInternal(t); 2707 isDerivedRawCache.put(t, result); 2708 } 2709 return result; 2710 } 2711 2712 public boolean isDerivedRawInternal(Type t) { 2713 if (t.isErroneous()) 2714 return false; 2715 return 2716 t.isRaw() || 2717 supertype(t) != Type.noType && isDerivedRaw(supertype(t)) || 2718 isDerivedRaw(interfaces(t)); 2719 } 2720 2721 public boolean isDerivedRaw(List<Type> ts) { 2722 List<Type> l = ts; 2723 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail; 2724 return l.nonEmpty(); 2725 } 2726 // </editor-fold> 2727 2728 // <editor-fold defaultstate="collapsed" desc="setBounds"> 2729 /** 2730 * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly, 2731 * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise 2732 * the supertype is simply left null (in this case, the supertype is assumed to be the head of 2733 * the bound list passed as second argument). Note that this check might cause a symbol completion. 2734 * Hence, this version of setBounds may not be called during a classfile read. 2735 * 2736 * @param t a type variable 2737 * @param bounds the bounds, must be nonempty 2738 */ 2739 public void setBounds(TypeVar t, List<Type> bounds) { 2740 setBounds(t, bounds, bounds.head.tsym.isInterface()); 2741 } 2742 2743 /** 2744 * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds. 2745 * This does not cause symbol completion as an extra parameter indicates as to whether all bounds 2746 * are interfaces - in which case the supertype is implicitly assumed to be 'Object'. 2747 * 2748 * @param t a type variable 2749 * @param bounds the bounds, must be nonempty 2750 * @param allInterfaces are all bounds interface types? 2751 */ 2752 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) { 2753 t.setUpperBound( bounds.tail.isEmpty() ? 2754 bounds.head : 2755 makeIntersectionType(bounds, allInterfaces) ); 2756 t.rank_field = -1; 2757 } 2758 // </editor-fold> 2759 2760 // <editor-fold defaultstate="collapsed" desc="getBounds"> 2761 /** 2762 * Return list of bounds of the given type variable. 2763 */ 2764 public List<Type> getBounds(TypeVar t) { 2765 if (t.getUpperBound().hasTag(NONE)) 2766 return List.nil(); 2767 else if (t.getUpperBound().isErroneous() || !t.getUpperBound().isCompound()) 2768 return List.of(t.getUpperBound()); 2769 else if ((erasure(t).tsym.flags() & INTERFACE) == 0) 2770 return interfaces(t).prepend(supertype(t)); 2771 else 2772 // No superclass was given in bounds. 2773 // In this case, supertype is Object, erasure is first interface. 2774 return interfaces(t); 2775 } 2776 // </editor-fold> 2777 2778 // <editor-fold defaultstate="collapsed" desc="classBound"> 2779 /** 2780 * If the given type is a (possibly selected) type variable, 2781 * return the bounding class of this type, otherwise return the 2782 * type itself. 2783 */ 2784 public Type classBound(Type t) { 2785 return classBound.visit(t); 2786 } 2787 // where 2788 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() { 2789 2790 public Type visitType(Type t, Void ignored) { 2791 return t; 2792 } 2793 2794 @Override 2795 public Type visitClassType(ClassType t, Void ignored) { 2796 Type outer1 = classBound(t.getEnclosingType()); 2797 if (outer1 != t.getEnclosingType()) 2798 return new ClassType(outer1, t.getTypeArguments(), t.tsym, 2799 t.getMetadata()); 2800 else 2801 return t; 2802 } 2803 2804 @Override 2805 public Type visitTypeVar(TypeVar t, Void ignored) { 2806 return classBound(supertype(t)); 2807 } 2808 2809 @Override 2810 public Type visitErrorType(ErrorType t, Void ignored) { 2811 return t; 2812 } 2813 }; 2814 // </editor-fold> 2815 2816 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence"> 2817 /** 2818 * Returns true iff the first signature is a <em>sub 2819 * signature</em> of the other. This is <b>not</b> an equivalence 2820 * relation. 2821 * 2822 * @jls 8.4.2 Method Signature 2823 * @see #overrideEquivalent(Type t, Type s) 2824 * @param t first signature (possibly raw). 2825 * @param s second signature (could be subjected to erasure). 2826 * @return true if t is a sub signature of s. 2827 */ 2828 public boolean isSubSignature(Type t, Type s) { 2829 return isSubSignature(t, s, true); 2830 } 2831 2832 public boolean isSubSignature(Type t, Type s, boolean strict) { 2833 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict); 2834 } 2835 2836 /** 2837 * Returns true iff these signatures are related by <em>override 2838 * equivalence</em>. This is the natural extension of 2839 * isSubSignature to an equivalence relation. 2840 * 2841 * @jls 8.4.2 Method Signature 2842 * @see #isSubSignature(Type t, Type s) 2843 * @param t a signature (possible raw, could be subjected to 2844 * erasure). 2845 * @param s a signature (possible raw, could be subjected to 2846 * erasure). 2847 * @return true if either argument is a sub signature of the other. 2848 */ 2849 public boolean overrideEquivalent(Type t, Type s) { 2850 return hasSameArgs(t, s) || 2851 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s); 2852 } 2853 2854 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) { 2855 for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) { 2856 if (msym.overrides(sym, origin, Types.this, true)) { 2857 return true; 2858 } 2859 } 2860 return false; 2861 } 2862 2863 /** 2864 * This enum defines the strategy for implementing most specific return type check 2865 * during the most specific and functional interface checks. 2866 */ 2867 public enum MostSpecificReturnCheck { 2868 /** 2869 * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling 2870 * method type variables (if either method is generic) and (ii) subtyping should be replaced 2871 * by type-equivalence for primitives. This is essentially an inlined version of 2872 * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been 2873 * replaced with a strict subtyping check. 2874 */ 2875 BASIC() { 2876 @Override 2877 public boolean test(Type mt1, Type mt2, Types types) { 2878 List<Type> tvars = mt1.getTypeArguments(); 2879 List<Type> svars = mt2.getTypeArguments(); 2880 Type t = mt1.getReturnType(); 2881 Type s = types.subst(mt2.getReturnType(), svars, tvars); 2882 return types.isSameType(t, s) || 2883 !t.isPrimitive() && 2884 !s.isPrimitive() && 2885 types.isSubtype(t, s); 2886 } 2887 }, 2888 /** 2889 * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2. 2890 */ 2891 RTS() { 2892 @Override 2893 public boolean test(Type mt1, Type mt2, Types types) { 2894 return types.returnTypeSubstitutable(mt1, mt2); 2895 } 2896 }; 2897 2898 public abstract boolean test(Type mt1, Type mt2, Types types); 2899 } 2900 2901 /** 2902 * Merge multiple abstract methods. The preferred method is a method that is a subsignature 2903 * of all the other signatures and whose return type is more specific {@see MostSpecificReturnCheck}. 2904 * The resulting preferred method has a thrown clause that is the intersection of the merged 2905 * methods' clauses. 2906 */ 2907 public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) { 2908 //first check for preconditions 2909 boolean shouldErase = false; 2910 List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes(); 2911 for (Symbol s : ambiguousInOrder) { 2912 if ((s.flags() & ABSTRACT) == 0 || 2913 (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) { 2914 return Optional.empty(); 2915 } else if (s.type.hasTag(FORALL)) { 2916 shouldErase = true; 2917 } 2918 } 2919 //then merge abstracts 2920 for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) { 2921 outer: for (Symbol s : ambiguousInOrder) { 2922 Type mt = memberType(site, s); 2923 List<Type> allThrown = mt.getThrownTypes(); 2924 for (Symbol s2 : ambiguousInOrder) { 2925 if (s != s2) { 2926 Type mt2 = memberType(site, s2); 2927 if (!isSubSignature(mt, mt2) || 2928 !mostSpecificReturnCheck.test(mt, mt2, this)) { 2929 //ambiguity cannot be resolved 2930 continue outer; 2931 } else { 2932 List<Type> thrownTypes2 = mt2.getThrownTypes(); 2933 if (!mt.hasTag(FORALL) && shouldErase) { 2934 thrownTypes2 = erasure(thrownTypes2); 2935 } else if (mt.hasTag(FORALL)) { 2936 //subsignature implies that if most specific is generic, then all other 2937 //methods are too 2938 Assert.check(mt2.hasTag(FORALL)); 2939 // if both are generic methods, adjust thrown types ahead of intersection computation 2940 thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments()); 2941 } 2942 allThrown = chk.intersect(allThrown, thrownTypes2); 2943 } 2944 } 2945 } 2946 return (allThrown == mt.getThrownTypes()) ? 2947 Optional.of(s) : 2948 Optional.of(new MethodSymbol( 2949 s.flags(), 2950 s.name, 2951 createMethodTypeWithThrown(s.type, allThrown), 2952 s.owner) { 2953 @Override 2954 public Symbol baseSymbol() { 2955 return s; 2956 } 2957 }); 2958 } 2959 } 2960 return Optional.empty(); 2961 } 2962 2963 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site"> 2964 class ImplementationCache { 2965 2966 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>(); 2967 2968 class Entry { 2969 final MethodSymbol cachedImpl; 2970 final Filter<Symbol> implFilter; 2971 final boolean checkResult; 2972 final int prevMark; 2973 2974 public Entry(MethodSymbol cachedImpl, 2975 Filter<Symbol> scopeFilter, 2976 boolean checkResult, 2977 int prevMark) { 2978 this.cachedImpl = cachedImpl; 2979 this.implFilter = scopeFilter; 2980 this.checkResult = checkResult; 2981 this.prevMark = prevMark; 2982 } 2983 2984 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) { 2985 return this.implFilter == scopeFilter && 2986 this.checkResult == checkResult && 2987 this.prevMark == mark; 2988 } 2989 } 2990 2991 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) { 2992 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms); 2993 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null; 2994 if (cache == null) { 2995 cache = new HashMap<>(); 2996 _map.put(ms, new SoftReference<>(cache)); 2997 } 2998 Entry e = cache.get(origin); 2999 CompoundScope members = membersClosure(origin.type, true); 3000 if (e == null || 3001 !e.matches(implFilter, checkResult, members.getMark())) { 3002 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter); 3003 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark())); 3004 return impl; 3005 } 3006 else { 3007 return e.cachedImpl; 3008 } 3009 } 3010 3011 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) { 3012 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) { 3013 t = skipTypeVars(t, false); 3014 TypeSymbol c = t.tsym; 3015 Symbol bestSoFar = null; 3016 for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) { 3017 if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) { 3018 bestSoFar = sym; 3019 if ((sym.flags() & ABSTRACT) == 0) { 3020 //if concrete impl is found, exit immediately 3021 break; 3022 } 3023 } 3024 } 3025 if (bestSoFar != null) { 3026 //return either the (only) concrete implementation or the first abstract one 3027 return (MethodSymbol)bestSoFar; 3028 } 3029 } 3030 return null; 3031 } 3032 } 3033 3034 private ImplementationCache implCache = new ImplementationCache(); 3035 3036 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) { 3037 return implCache.get(ms, origin, checkResult, implFilter); 3038 } 3039 // </editor-fold> 3040 3041 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site"> 3042 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> { 3043 3044 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>(); 3045 3046 Set<TypeSymbol> seenTypes = new HashSet<>(); 3047 3048 class MembersScope extends CompoundScope { 3049 3050 CompoundScope scope; 3051 3052 public MembersScope(CompoundScope scope) { 3053 super(scope.owner); 3054 this.scope = scope; 3055 } 3056 3057 Filter<Symbol> combine(Filter<Symbol> sf) { 3058 return s -> !s.owner.isInterface() && (sf == null || sf.accepts(s)); 3059 } 3060 3061 @Override 3062 public Iterable<Symbol> getSymbols(Filter<Symbol> sf, LookupKind lookupKind) { 3063 return scope.getSymbols(combine(sf), lookupKind); 3064 } 3065 3066 @Override 3067 public Iterable<Symbol> getSymbolsByName(Name name, Filter<Symbol> sf, LookupKind lookupKind) { 3068 return scope.getSymbolsByName(name, combine(sf), lookupKind); 3069 } 3070 3071 @Override 3072 public int getMark() { 3073 return scope.getMark(); 3074 } 3075 } 3076 3077 CompoundScope nilScope; 3078 3079 /** members closure visitor methods **/ 3080 3081 public CompoundScope visitType(Type t, Void _unused) { 3082 if (nilScope == null) { 3083 nilScope = new CompoundScope(syms.noSymbol); 3084 } 3085 return nilScope; 3086 } 3087 3088 @Override 3089 public CompoundScope visitClassType(ClassType t, Void _unused) { 3090 if (!seenTypes.add(t.tsym)) { 3091 //this is possible when an interface is implemented in multiple 3092 //superclasses, or when a class hierarchy is circular - in such 3093 //cases we don't need to recurse (empty scope is returned) 3094 return new CompoundScope(t.tsym); 3095 } 3096 try { 3097 seenTypes.add(t.tsym); 3098 ClassSymbol csym = (ClassSymbol)t.tsym; 3099 CompoundScope membersClosure = _map.get(csym); 3100 if (membersClosure == null) { 3101 membersClosure = new CompoundScope(csym); 3102 for (Type i : interfaces(t)) { 3103 membersClosure.prependSubScope(visit(i, null)); 3104 } 3105 membersClosure.prependSubScope(visit(supertype(t), null)); 3106 membersClosure.prependSubScope(csym.members()); 3107 _map.put(csym, membersClosure); 3108 } 3109 return membersClosure; 3110 } 3111 finally { 3112 seenTypes.remove(t.tsym); 3113 } 3114 } 3115 3116 @Override 3117 public CompoundScope visitTypeVar(TypeVar t, Void _unused) { 3118 return visit(t.getUpperBound(), null); 3119 } 3120 } 3121 3122 private MembersClosureCache membersCache = new MembersClosureCache(); 3123 3124 public CompoundScope membersClosure(Type site, boolean skipInterface) { 3125 CompoundScope cs = membersCache.visit(site, null); 3126 Assert.checkNonNull(cs, () -> "type " + site); 3127 return skipInterface ? membersCache.new MembersScope(cs) : cs; 3128 } 3129 // </editor-fold> 3130 3131 3132 /** Return first abstract member of class `sym'. 3133 */ 3134 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) { 3135 try { 3136 return firstUnimplementedAbstractImpl(sym, sym); 3137 } catch (CompletionFailure ex) { 3138 chk.completionError(enter.getEnv(sym).tree.pos(), ex); 3139 return null; 3140 } 3141 } 3142 //where: 3143 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) { 3144 MethodSymbol undef = null; 3145 // Do not bother to search in classes that are not abstract, 3146 // since they cannot have abstract members. 3147 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) { 3148 Scope s = c.members(); 3149 for (Symbol sym : s.getSymbols(NON_RECURSIVE)) { 3150 if (sym.kind == MTH && 3151 (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) { 3152 MethodSymbol absmeth = (MethodSymbol)sym; 3153 MethodSymbol implmeth = absmeth.implementation(impl, this, true); 3154 if (implmeth == null || implmeth == absmeth) { 3155 //look for default implementations 3156 if (allowDefaultMethods) { 3157 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head; 3158 if (prov != null && prov.overrides(absmeth, impl, this, true)) { 3159 implmeth = prov; 3160 } 3161 } 3162 } 3163 if (implmeth == null || implmeth == absmeth) { 3164 undef = absmeth; 3165 break; 3166 } 3167 } 3168 } 3169 if (undef == null) { 3170 Type st = supertype(c.type); 3171 if (st.hasTag(CLASS)) 3172 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym); 3173 } 3174 for (List<Type> l = interfaces(c.type); 3175 undef == null && l.nonEmpty(); 3176 l = l.tail) { 3177 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym); 3178 } 3179 } 3180 return undef; 3181 } 3182 3183 public class CandidatesCache { 3184 public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>(); 3185 3186 class Entry { 3187 Type site; 3188 MethodSymbol msym; 3189 3190 Entry(Type site, MethodSymbol msym) { 3191 this.site = site; 3192 this.msym = msym; 3193 } 3194 3195 @Override 3196 public boolean equals(Object obj) { 3197 if (obj instanceof Entry) { 3198 Entry e = (Entry)obj; 3199 return e.msym == msym && isSameType(site, e.site); 3200 } else { 3201 return false; 3202 } 3203 } 3204 3205 @Override 3206 public int hashCode() { 3207 return Types.this.hashCode(site) & ~msym.hashCode(); 3208 } 3209 } 3210 3211 public List<MethodSymbol> get(Entry e) { 3212 return cache.get(e); 3213 } 3214 3215 public void put(Entry e, List<MethodSymbol> msymbols) { 3216 cache.put(e, msymbols); 3217 } 3218 } 3219 3220 public CandidatesCache candidatesCache = new CandidatesCache(); 3221 3222 //where 3223 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) { 3224 CandidatesCache.Entry e = candidatesCache.new Entry(site, ms); 3225 List<MethodSymbol> candidates = candidatesCache.get(e); 3226 if (candidates == null) { 3227 Filter<Symbol> filter = new MethodFilter(ms, site); 3228 List<MethodSymbol> candidates2 = List.nil(); 3229 for (Symbol s : membersClosure(site, false).getSymbols(filter)) { 3230 if (!site.tsym.isInterface() && !s.owner.isInterface()) { 3231 return List.of((MethodSymbol)s); 3232 } else if (!candidates2.contains(s)) { 3233 candidates2 = candidates2.prepend((MethodSymbol)s); 3234 } 3235 } 3236 candidates = prune(candidates2); 3237 candidatesCache.put(e, candidates); 3238 } 3239 return candidates; 3240 } 3241 3242 public List<MethodSymbol> prune(List<MethodSymbol> methods) { 3243 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>(); 3244 for (MethodSymbol m1 : methods) { 3245 boolean isMin_m1 = true; 3246 for (MethodSymbol m2 : methods) { 3247 if (m1 == m2) continue; 3248 if (m2.owner != m1.owner && 3249 asSuper(m2.owner.type, m1.owner) != null) { 3250 isMin_m1 = false; 3251 break; 3252 } 3253 } 3254 if (isMin_m1) 3255 methodsMin.append(m1); 3256 } 3257 return methodsMin.toList(); 3258 } 3259 // where 3260 private class MethodFilter implements Filter<Symbol> { 3261 3262 Symbol msym; 3263 Type site; 3264 3265 MethodFilter(Symbol msym, Type site) { 3266 this.msym = msym; 3267 this.site = site; 3268 } 3269 3270 public boolean accepts(Symbol s) { 3271 return s.kind == MTH && 3272 s.name == msym.name && 3273 (s.flags() & SYNTHETIC) == 0 && 3274 s.isInheritedIn(site.tsym, Types.this) && 3275 overrideEquivalent(memberType(site, s), memberType(site, msym)); 3276 } 3277 } 3278 // </editor-fold> 3279 3280 /** 3281 * Does t have the same arguments as s? It is assumed that both 3282 * types are (possibly polymorphic) method types. Monomorphic 3283 * method types "have the same arguments", if their argument lists 3284 * are equal. Polymorphic method types "have the same arguments", 3285 * if they have the same arguments after renaming all type 3286 * variables of one to corresponding type variables in the other, 3287 * where correspondence is by position in the type parameter list. 3288 */ 3289 public boolean hasSameArgs(Type t, Type s) { 3290 return hasSameArgs(t, s, true); 3291 } 3292 3293 public boolean hasSameArgs(Type t, Type s, boolean strict) { 3294 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict); 3295 } 3296 3297 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) { 3298 return hasSameArgs.visit(t, s); 3299 } 3300 // where 3301 private class HasSameArgs extends TypeRelation { 3302 3303 boolean strict; 3304 3305 public HasSameArgs(boolean strict) { 3306 this.strict = strict; 3307 } 3308 3309 public Boolean visitType(Type t, Type s) { 3310 throw new AssertionError(); 3311 } 3312 3313 @Override 3314 public Boolean visitMethodType(MethodType t, Type s) { 3315 return s.hasTag(METHOD) 3316 && containsTypeEquivalent(t.argtypes, s.getParameterTypes()); 3317 } 3318 3319 @Override 3320 public Boolean visitForAll(ForAll t, Type s) { 3321 if (!s.hasTag(FORALL)) 3322 return strict ? false : visitMethodType(t.asMethodType(), s); 3323 3324 ForAll forAll = (ForAll)s; 3325 return hasSameBounds(t, forAll) 3326 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars)); 3327 } 3328 3329 @Override 3330 public Boolean visitErrorType(ErrorType t, Type s) { 3331 return false; 3332 } 3333 } 3334 3335 TypeRelation hasSameArgs_strict = new HasSameArgs(true); 3336 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false); 3337 3338 // </editor-fold> 3339 3340 // <editor-fold defaultstate="collapsed" desc="subst"> 3341 public List<Type> subst(List<Type> ts, 3342 List<Type> from, 3343 List<Type> to) { 3344 return ts.map(new Subst(from, to)); 3345 } 3346 3347 /** 3348 * Substitute all occurrences of a type in `from' with the 3349 * corresponding type in `to' in 't'. Match lists `from' and `to' 3350 * from the right: If lists have different length, discard leading 3351 * elements of the longer list. 3352 */ 3353 public Type subst(Type t, List<Type> from, List<Type> to) { 3354 return t.map(new Subst(from, to)); 3355 } 3356 3357 private class Subst extends StructuralTypeMapping<Void> { 3358 List<Type> from; 3359 List<Type> to; 3360 3361 public Subst(List<Type> from, List<Type> to) { 3362 int fromLength = from.length(); 3363 int toLength = to.length(); 3364 while (fromLength > toLength) { 3365 fromLength--; 3366 from = from.tail; 3367 } 3368 while (fromLength < toLength) { 3369 toLength--; 3370 to = to.tail; 3371 } 3372 this.from = from; 3373 this.to = to; 3374 } 3375 3376 @Override 3377 public Type visitTypeVar(TypeVar t, Void ignored) { 3378 for (List<Type> from = this.from, to = this.to; 3379 from.nonEmpty(); 3380 from = from.tail, to = to.tail) { 3381 if (t.equalsIgnoreMetadata(from.head)) { 3382 return to.head.withTypeVar(t); 3383 } 3384 } 3385 return t; 3386 } 3387 3388 @Override 3389 public Type visitClassType(ClassType t, Void ignored) { 3390 if (!t.isCompound()) { 3391 return super.visitClassType(t, ignored); 3392 } else { 3393 Type st = visit(supertype(t)); 3394 List<Type> is = visit(interfaces(t), ignored); 3395 if (st == supertype(t) && is == interfaces(t)) 3396 return t; 3397 else 3398 return makeIntersectionType(is.prepend(st)); 3399 } 3400 } 3401 3402 @Override 3403 public Type visitWildcardType(WildcardType t, Void ignored) { 3404 WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored); 3405 if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) { 3406 t2.type = wildUpperBound(t2.type); 3407 } 3408 return t2; 3409 } 3410 3411 @Override 3412 public Type visitForAll(ForAll t, Void ignored) { 3413 if (Type.containsAny(to, t.tvars)) { 3414 //perform alpha-renaming of free-variables in 't' 3415 //if 'to' types contain variables that are free in 't' 3416 List<Type> freevars = newInstances(t.tvars); 3417 t = new ForAll(freevars, 3418 Types.this.subst(t.qtype, t.tvars, freevars)); 3419 } 3420 List<Type> tvars1 = substBounds(t.tvars, from, to); 3421 Type qtype1 = visit(t.qtype); 3422 if (tvars1 == t.tvars && qtype1 == t.qtype) { 3423 return t; 3424 } else if (tvars1 == t.tvars) { 3425 return new ForAll(tvars1, qtype1) { 3426 @Override 3427 public boolean needsStripping() { 3428 return true; 3429 } 3430 }; 3431 } else { 3432 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) { 3433 @Override 3434 public boolean needsStripping() { 3435 return true; 3436 } 3437 }; 3438 } 3439 } 3440 } 3441 3442 public List<Type> substBounds(List<Type> tvars, 3443 List<Type> from, 3444 List<Type> to) { 3445 if (tvars.isEmpty()) 3446 return tvars; 3447 ListBuffer<Type> newBoundsBuf = new ListBuffer<>(); 3448 boolean changed = false; 3449 // calculate new bounds 3450 for (Type t : tvars) { 3451 TypeVar tv = (TypeVar) t; 3452 Type bound = subst(tv.getUpperBound(), from, to); 3453 if (bound != tv.getUpperBound()) 3454 changed = true; 3455 newBoundsBuf.append(bound); 3456 } 3457 if (!changed) 3458 return tvars; 3459 ListBuffer<Type> newTvars = new ListBuffer<>(); 3460 // create new type variables without bounds 3461 for (Type t : tvars) { 3462 newTvars.append(new TypeVar(t.tsym, null, syms.botType, 3463 t.getMetadata())); 3464 } 3465 // the new bounds should use the new type variables in place 3466 // of the old 3467 List<Type> newBounds = newBoundsBuf.toList(); 3468 from = tvars; 3469 to = newTvars.toList(); 3470 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) { 3471 newBounds.head = subst(newBounds.head, from, to); 3472 } 3473 newBounds = newBoundsBuf.toList(); 3474 // set the bounds of new type variables to the new bounds 3475 for (Type t : newTvars.toList()) { 3476 TypeVar tv = (TypeVar) t; 3477 tv.setUpperBound( newBounds.head ); 3478 newBounds = newBounds.tail; 3479 } 3480 return newTvars.toList(); 3481 } 3482 3483 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) { 3484 Type bound1 = subst(t.getUpperBound(), from, to); 3485 if (bound1 == t.getUpperBound()) 3486 return t; 3487 else { 3488 // create new type variable without bounds 3489 TypeVar tv = new TypeVar(t.tsym, null, syms.botType, 3490 t.getMetadata()); 3491 // the new bound should use the new type variable in place 3492 // of the old 3493 tv.setUpperBound( subst(bound1, List.of(t), List.of(tv)) ); 3494 return tv; 3495 } 3496 } 3497 // </editor-fold> 3498 3499 // <editor-fold defaultstate="collapsed" desc="hasSameBounds"> 3500 /** 3501 * Does t have the same bounds for quantified variables as s? 3502 */ 3503 public boolean hasSameBounds(ForAll t, ForAll s) { 3504 List<Type> l1 = t.tvars; 3505 List<Type> l2 = s.tvars; 3506 while (l1.nonEmpty() && l2.nonEmpty() && 3507 isSameType(l1.head.getUpperBound(), 3508 subst(l2.head.getUpperBound(), 3509 s.tvars, 3510 t.tvars))) { 3511 l1 = l1.tail; 3512 l2 = l2.tail; 3513 } 3514 return l1.isEmpty() && l2.isEmpty(); 3515 } 3516 // </editor-fold> 3517 3518 // <editor-fold defaultstate="collapsed" desc="newInstances"> 3519 /** Create new vector of type variables from list of variables 3520 * changing all recursive bounds from old to new list. 3521 */ 3522 public List<Type> newInstances(List<Type> tvars) { 3523 List<Type> tvars1 = tvars.map(newInstanceFun); 3524 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) { 3525 TypeVar tv = (TypeVar) l.head; 3526 tv.setUpperBound( subst(tv.getUpperBound(), tvars, tvars1) ); 3527 } 3528 return tvars1; 3529 } 3530 private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() { 3531 @Override 3532 public TypeVar visitTypeVar(TypeVar t, Void _unused) { 3533 return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata()); 3534 } 3535 }; 3536 // </editor-fold> 3537 3538 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) { 3539 return original.accept(methodWithParameters, newParams); 3540 } 3541 // where 3542 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() { 3543 public Type visitType(Type t, List<Type> newParams) { 3544 throw new IllegalArgumentException("Not a method type: " + t); 3545 } 3546 public Type visitMethodType(MethodType t, List<Type> newParams) { 3547 return new MethodType(newParams, t.restype, t.thrown, t.tsym); 3548 } 3549 public Type visitForAll(ForAll t, List<Type> newParams) { 3550 return new ForAll(t.tvars, t.qtype.accept(this, newParams)); 3551 } 3552 }; 3553 3554 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) { 3555 return original.accept(methodWithThrown, newThrown); 3556 } 3557 // where 3558 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() { 3559 public Type visitType(Type t, List<Type> newThrown) { 3560 throw new IllegalArgumentException("Not a method type: " + t); 3561 } 3562 public Type visitMethodType(MethodType t, List<Type> newThrown) { 3563 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym); 3564 } 3565 public Type visitForAll(ForAll t, List<Type> newThrown) { 3566 return new ForAll(t.tvars, t.qtype.accept(this, newThrown)); 3567 } 3568 }; 3569 3570 public Type createMethodTypeWithReturn(Type original, Type newReturn) { 3571 return original.accept(methodWithReturn, newReturn); 3572 } 3573 // where 3574 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() { 3575 public Type visitType(Type t, Type newReturn) { 3576 throw new IllegalArgumentException("Not a method type: " + t); 3577 } 3578 public Type visitMethodType(MethodType t, Type newReturn) { 3579 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) { 3580 @Override 3581 public Type baseType() { 3582 return t; 3583 } 3584 }; 3585 } 3586 public Type visitForAll(ForAll t, Type newReturn) { 3587 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) { 3588 @Override 3589 public Type baseType() { 3590 return t; 3591 } 3592 }; 3593 } 3594 }; 3595 3596 // <editor-fold defaultstate="collapsed" desc="createErrorType"> 3597 public Type createErrorType(Type originalType) { 3598 return new ErrorType(originalType, syms.errSymbol); 3599 } 3600 3601 public Type createErrorType(ClassSymbol c, Type originalType) { 3602 return new ErrorType(c, originalType); 3603 } 3604 3605 public Type createErrorType(Name name, TypeSymbol container, Type originalType) { 3606 return new ErrorType(name, container, originalType); 3607 } 3608 // </editor-fold> 3609 3610 // <editor-fold defaultstate="collapsed" desc="rank"> 3611 /** 3612 * The rank of a class is the length of the longest path between 3613 * the class and java.lang.Object in the class inheritance 3614 * graph. Undefined for all but reference types. 3615 */ 3616 public int rank(Type t) { 3617 switch(t.getTag()) { 3618 case CLASS: { 3619 ClassType cls = (ClassType)t; 3620 if (cls.rank_field < 0) { 3621 Name fullname = cls.tsym.getQualifiedName(); 3622 if (fullname == names.java_lang_Object) 3623 cls.rank_field = 0; 3624 else { 3625 int r = rank(supertype(cls)); 3626 for (List<Type> l = interfaces(cls); 3627 l.nonEmpty(); 3628 l = l.tail) { 3629 if (rank(l.head) > r) 3630 r = rank(l.head); 3631 } 3632 cls.rank_field = r + 1; 3633 } 3634 } 3635 return cls.rank_field; 3636 } 3637 case TYPEVAR: { 3638 TypeVar tvar = (TypeVar)t; 3639 if (tvar.rank_field < 0) { 3640 int r = rank(supertype(tvar)); 3641 for (List<Type> l = interfaces(tvar); 3642 l.nonEmpty(); 3643 l = l.tail) { 3644 if (rank(l.head) > r) r = rank(l.head); 3645 } 3646 tvar.rank_field = r + 1; 3647 } 3648 return tvar.rank_field; 3649 } 3650 case ERROR: 3651 case NONE: 3652 return 0; 3653 default: 3654 throw new AssertionError(); 3655 } 3656 } 3657 // </editor-fold> 3658 3659 /** 3660 * Helper method for generating a string representation of a given type 3661 * accordingly to a given locale 3662 */ 3663 public String toString(Type t, Locale locale) { 3664 return Printer.createStandardPrinter(messages).visit(t, locale); 3665 } 3666 3667 /** 3668 * Helper method for generating a string representation of a given type 3669 * accordingly to a given locale 3670 */ 3671 public String toString(Symbol t, Locale locale) { 3672 return Printer.createStandardPrinter(messages).visit(t, locale); 3673 } 3674 3675 // <editor-fold defaultstate="collapsed" desc="toString"> 3676 /** 3677 * This toString is slightly more descriptive than the one on Type. 3678 * 3679 * @deprecated Types.toString(Type t, Locale l) provides better support 3680 * for localization 3681 */ 3682 @Deprecated 3683 public String toString(Type t) { 3684 if (t.hasTag(FORALL)) { 3685 ForAll forAll = (ForAll)t; 3686 return typaramsString(forAll.tvars) + forAll.qtype; 3687 } 3688 return "" + t; 3689 } 3690 // where 3691 private String typaramsString(List<Type> tvars) { 3692 StringBuilder s = new StringBuilder(); 3693 s.append('<'); 3694 boolean first = true; 3695 for (Type t : tvars) { 3696 if (!first) s.append(", "); 3697 first = false; 3698 appendTyparamString(((TypeVar)t), s); 3699 } 3700 s.append('>'); 3701 return s.toString(); 3702 } 3703 private void appendTyparamString(TypeVar t, StringBuilder buf) { 3704 buf.append(t); 3705 if (t.getUpperBound() == null || 3706 t.getUpperBound().tsym.getQualifiedName() == names.java_lang_Object) 3707 return; 3708 buf.append(" extends "); // Java syntax; no need for i18n 3709 Type bound = t.getUpperBound(); 3710 if (!bound.isCompound()) { 3711 buf.append(bound); 3712 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) { 3713 buf.append(supertype(t)); 3714 for (Type intf : interfaces(t)) { 3715 buf.append('&'); 3716 buf.append(intf); 3717 } 3718 } else { 3719 // No superclass was given in bounds. 3720 // In this case, supertype is Object, erasure is first interface. 3721 boolean first = true; 3722 for (Type intf : interfaces(t)) { 3723 if (!first) buf.append('&'); 3724 first = false; 3725 buf.append(intf); 3726 } 3727 } 3728 } 3729 // </editor-fold> 3730 3731 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types"> 3732 /** 3733 * A cache for closures. 3734 * 3735 * <p>A closure is a list of all the supertypes and interfaces of 3736 * a class or interface type, ordered by ClassSymbol.precedes 3737 * (that is, subclasses come first, arbitrary but fixed 3738 * otherwise). 3739 */ 3740 private Map<Type,List<Type>> closureCache = new HashMap<>(); 3741 3742 /** 3743 * Returns the closure of a class or interface type. 3744 */ 3745 public List<Type> closure(Type t) { 3746 List<Type> cl = closureCache.get(t); 3747 if (cl == null) { 3748 Type st = supertype(t); 3749 if (!t.isCompound()) { 3750 if (st.hasTag(CLASS)) { 3751 cl = insert(closure(st), t); 3752 } else if (st.hasTag(TYPEVAR)) { 3753 cl = closure(st).prepend(t); 3754 } else { 3755 cl = List.of(t); 3756 } 3757 } else { 3758 cl = closure(supertype(t)); 3759 } 3760 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) 3761 cl = union(cl, closure(l.head)); 3762 closureCache.put(t, cl); 3763 } 3764 return cl; 3765 } 3766 3767 /** 3768 * Collect types into a new closure (using a @code{ClosureHolder}) 3769 */ 3770 public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) { 3771 return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip), 3772 ClosureHolder::add, 3773 ClosureHolder::merge, 3774 ClosureHolder::closure); 3775 } 3776 //where 3777 class ClosureHolder { 3778 List<Type> closure; 3779 final boolean minClosure; 3780 final BiPredicate<Type, Type> shouldSkip; 3781 3782 ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) { 3783 this.closure = List.nil(); 3784 this.minClosure = minClosure; 3785 this.shouldSkip = shouldSkip; 3786 } 3787 3788 void add(Type type) { 3789 closure = insert(closure, type, shouldSkip); 3790 } 3791 3792 ClosureHolder merge(ClosureHolder other) { 3793 closure = union(closure, other.closure, shouldSkip); 3794 return this; 3795 } 3796 3797 List<Type> closure() { 3798 return minClosure ? closureMin(closure) : closure; 3799 } 3800 } 3801 3802 BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym; 3803 3804 /** 3805 * Insert a type in a closure 3806 */ 3807 public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) { 3808 if (cl.isEmpty()) { 3809 return cl.prepend(t); 3810 } else if (shouldSkip.test(t, cl.head)) { 3811 return cl; 3812 } else if (t.tsym.precedes(cl.head.tsym, this)) { 3813 return cl.prepend(t); 3814 } else { 3815 // t comes after head, or the two are unrelated 3816 return insert(cl.tail, t, shouldSkip).prepend(cl.head); 3817 } 3818 } 3819 3820 public List<Type> insert(List<Type> cl, Type t) { 3821 return insert(cl, t, basicClosureSkip); 3822 } 3823 3824 /** 3825 * Form the union of two closures 3826 */ 3827 public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) { 3828 if (cl1.isEmpty()) { 3829 return cl2; 3830 } else if (cl2.isEmpty()) { 3831 return cl1; 3832 } else if (shouldSkip.test(cl1.head, cl2.head)) { 3833 return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head); 3834 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) { 3835 return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head); 3836 } else { 3837 return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head); 3838 } 3839 } 3840 3841 public List<Type> union(List<Type> cl1, List<Type> cl2) { 3842 return union(cl1, cl2, basicClosureSkip); 3843 } 3844 3845 /** 3846 * Intersect two closures 3847 */ 3848 public List<Type> intersect(List<Type> cl1, List<Type> cl2) { 3849 if (cl1 == cl2) 3850 return cl1; 3851 if (cl1.isEmpty() || cl2.isEmpty()) 3852 return List.nil(); 3853 if (cl1.head.tsym.precedes(cl2.head.tsym, this)) 3854 return intersect(cl1.tail, cl2); 3855 if (cl2.head.tsym.precedes(cl1.head.tsym, this)) 3856 return intersect(cl1, cl2.tail); 3857 if (isSameType(cl1.head, cl2.head)) 3858 return intersect(cl1.tail, cl2.tail).prepend(cl1.head); 3859 if (cl1.head.tsym == cl2.head.tsym && 3860 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) { 3861 if (cl1.head.isParameterized() && cl2.head.isParameterized()) { 3862 Type merge = merge(cl1.head,cl2.head); 3863 return intersect(cl1.tail, cl2.tail).prepend(merge); 3864 } 3865 if (cl1.head.isRaw() || cl2.head.isRaw()) 3866 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head)); 3867 } 3868 return intersect(cl1.tail, cl2.tail); 3869 } 3870 // where 3871 class TypePair { 3872 final Type t1; 3873 final Type t2;; 3874 3875 TypePair(Type t1, Type t2) { 3876 this.t1 = t1; 3877 this.t2 = t2; 3878 } 3879 @Override 3880 public int hashCode() { 3881 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2); 3882 } 3883 @Override 3884 public boolean equals(Object obj) { 3885 if (!(obj instanceof TypePair)) 3886 return false; 3887 TypePair typePair = (TypePair)obj; 3888 return isSameType(t1, typePair.t1) 3889 && isSameType(t2, typePair.t2); 3890 } 3891 } 3892 Set<TypePair> mergeCache = new HashSet<>(); 3893 private Type merge(Type c1, Type c2) { 3894 ClassType class1 = (ClassType) c1; 3895 List<Type> act1 = class1.getTypeArguments(); 3896 ClassType class2 = (ClassType) c2; 3897 List<Type> act2 = class2.getTypeArguments(); 3898 ListBuffer<Type> merged = new ListBuffer<>(); 3899 List<Type> typarams = class1.tsym.type.getTypeArguments(); 3900 3901 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) { 3902 if (containsType(act1.head, act2.head)) { 3903 merged.append(act1.head); 3904 } else if (containsType(act2.head, act1.head)) { 3905 merged.append(act2.head); 3906 } else { 3907 TypePair pair = new TypePair(c1, c2); 3908 Type m; 3909 if (mergeCache.add(pair)) { 3910 m = new WildcardType(lub(wildUpperBound(act1.head), 3911 wildUpperBound(act2.head)), 3912 BoundKind.EXTENDS, 3913 syms.boundClass); 3914 mergeCache.remove(pair); 3915 } else { 3916 m = new WildcardType(syms.objectType, 3917 BoundKind.UNBOUND, 3918 syms.boundClass); 3919 } 3920 merged.append(m.withTypeVar(typarams.head)); 3921 } 3922 act1 = act1.tail; 3923 act2 = act2.tail; 3924 typarams = typarams.tail; 3925 } 3926 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty()); 3927 // There is no spec detailing how type annotations are to 3928 // be inherited. So set it to noAnnotations for now 3929 return new ClassType(class1.getEnclosingType(), merged.toList(), 3930 class1.tsym); 3931 } 3932 3933 /** 3934 * Return the minimum type of a closure, a compound type if no 3935 * unique minimum exists. 3936 */ 3937 private Type compoundMin(List<Type> cl) { 3938 if (cl.isEmpty()) return syms.objectType; 3939 List<Type> compound = closureMin(cl); 3940 if (compound.isEmpty()) 3941 return null; 3942 else if (compound.tail.isEmpty()) 3943 return compound.head; 3944 else 3945 return makeIntersectionType(compound); 3946 } 3947 3948 /** 3949 * Return the minimum types of a closure, suitable for computing 3950 * compoundMin or glb. 3951 */ 3952 private List<Type> closureMin(List<Type> cl) { 3953 ListBuffer<Type> classes = new ListBuffer<>(); 3954 ListBuffer<Type> interfaces = new ListBuffer<>(); 3955 Set<Type> toSkip = new HashSet<>(); 3956 while (!cl.isEmpty()) { 3957 Type current = cl.head; 3958 boolean keep = !toSkip.contains(current); 3959 if (keep && current.hasTag(TYPEVAR)) { 3960 // skip lower-bounded variables with a subtype in cl.tail 3961 for (Type t : cl.tail) { 3962 if (isSubtypeNoCapture(t, current)) { 3963 keep = false; 3964 break; 3965 } 3966 } 3967 } 3968 if (keep) { 3969 if (current.isInterface()) 3970 interfaces.append(current); 3971 else 3972 classes.append(current); 3973 for (Type t : cl.tail) { 3974 // skip supertypes of 'current' in cl.tail 3975 if (isSubtypeNoCapture(current, t)) 3976 toSkip.add(t); 3977 } 3978 } 3979 cl = cl.tail; 3980 } 3981 return classes.appendList(interfaces).toList(); 3982 } 3983 3984 /** 3985 * Return the least upper bound of list of types. if the lub does 3986 * not exist return null. 3987 */ 3988 public Type lub(List<Type> ts) { 3989 return lub(ts.toArray(new Type[ts.length()])); 3990 } 3991 3992 /** 3993 * Return the least upper bound (lub) of set of types. If the lub 3994 * does not exist return the type of null (bottom). 3995 */ 3996 public Type lub(Type... ts) { 3997 final int UNKNOWN_BOUND = 0; 3998 final int ARRAY_BOUND = 1; 3999 final int CLASS_BOUND = 2; 4000 4001 int[] kinds = new int[ts.length]; 4002 4003 int boundkind = UNKNOWN_BOUND; 4004 for (int i = 0 ; i < ts.length ; i++) { 4005 Type t = ts[i]; 4006 switch (t.getTag()) { 4007 case CLASS: 4008 boundkind |= kinds[i] = CLASS_BOUND; 4009 break; 4010 case ARRAY: 4011 boundkind |= kinds[i] = ARRAY_BOUND; 4012 break; 4013 case TYPEVAR: 4014 do { 4015 t = t.getUpperBound(); 4016 } while (t.hasTag(TYPEVAR)); 4017 if (t.hasTag(ARRAY)) { 4018 boundkind |= kinds[i] = ARRAY_BOUND; 4019 } else { 4020 boundkind |= kinds[i] = CLASS_BOUND; 4021 } 4022 break; 4023 default: 4024 kinds[i] = UNKNOWN_BOUND; 4025 if (t.isPrimitive()) 4026 return syms.errType; 4027 } 4028 } 4029 switch (boundkind) { 4030 case 0: 4031 return syms.botType; 4032 4033 case ARRAY_BOUND: 4034 // calculate lub(A[], B[]) 4035 Type[] elements = new Type[ts.length]; 4036 for (int i = 0 ; i < ts.length ; i++) { 4037 Type elem = elements[i] = elemTypeFun.apply(ts[i]); 4038 if (elem.isPrimitive()) { 4039 // if a primitive type is found, then return 4040 // arraySuperType unless all the types are the 4041 // same 4042 Type first = ts[0]; 4043 for (int j = 1 ; j < ts.length ; j++) { 4044 if (!isSameType(first, ts[j])) { 4045 // lub(int[], B[]) is Cloneable & Serializable 4046 return arraySuperType(); 4047 } 4048 } 4049 // all the array types are the same, return one 4050 // lub(int[], int[]) is int[] 4051 return first; 4052 } 4053 } 4054 // lub(A[], B[]) is lub(A, B)[] 4055 return new ArrayType(lub(elements), syms.arrayClass); 4056 4057 case CLASS_BOUND: 4058 // calculate lub(A, B) 4059 int startIdx = 0; 4060 for (int i = 0; i < ts.length ; i++) { 4061 Type t = ts[i]; 4062 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) { 4063 break; 4064 } else { 4065 startIdx++; 4066 } 4067 } 4068 Assert.check(startIdx < ts.length); 4069 //step 1 - compute erased candidate set (EC) 4070 List<Type> cl = erasedSupertypes(ts[startIdx]); 4071 for (int i = startIdx + 1 ; i < ts.length ; i++) { 4072 Type t = ts[i]; 4073 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) 4074 cl = intersect(cl, erasedSupertypes(t)); 4075 } 4076 //step 2 - compute minimal erased candidate set (MEC) 4077 List<Type> mec = closureMin(cl); 4078 //step 3 - for each element G in MEC, compute lci(Inv(G)) 4079 List<Type> candidates = List.nil(); 4080 for (Type erasedSupertype : mec) { 4081 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym)); 4082 for (int i = startIdx + 1 ; i < ts.length ; i++) { 4083 Type superType = asSuper(ts[i], erasedSupertype.tsym); 4084 lci = intersect(lci, superType != null ? List.of(superType) : List.nil()); 4085 } 4086 candidates = candidates.appendList(lci); 4087 } 4088 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that 4089 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn)) 4090 return compoundMin(candidates); 4091 4092 default: 4093 // calculate lub(A, B[]) 4094 List<Type> classes = List.of(arraySuperType()); 4095 for (int i = 0 ; i < ts.length ; i++) { 4096 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays 4097 classes = classes.prepend(ts[i]); 4098 } 4099 // lub(A, B[]) is lub(A, arraySuperType) 4100 return lub(classes); 4101 } 4102 } 4103 // where 4104 List<Type> erasedSupertypes(Type t) { 4105 ListBuffer<Type> buf = new ListBuffer<>(); 4106 for (Type sup : closure(t)) { 4107 if (sup.hasTag(TYPEVAR)) { 4108 buf.append(sup); 4109 } else { 4110 buf.append(erasure(sup)); 4111 } 4112 } 4113 return buf.toList(); 4114 } 4115 4116 private Type arraySuperType = null; 4117 private Type arraySuperType() { 4118 // initialized lazily to avoid problems during compiler startup 4119 if (arraySuperType == null) { 4120 synchronized (this) { 4121 if (arraySuperType == null) { 4122 // JLS 10.8: all arrays implement Cloneable and Serializable. 4123 List<Type> ifaces = injectTopInterfaceTypes ? 4124 List.of(syms.serializableType, syms.cloneableType, syms.identityObjectType): 4125 List.of(syms.serializableType, syms.cloneableType); 4126 arraySuperType = makeIntersectionType(ifaces, true); 4127 } 4128 } 4129 } 4130 return arraySuperType; 4131 } 4132 // </editor-fold> 4133 4134 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound"> 4135 public Type glb(List<Type> ts) { 4136 Type t1 = ts.head; 4137 for (Type t2 : ts.tail) { 4138 if (t1.isErroneous()) 4139 return t1; 4140 t1 = glb(t1, t2); 4141 } 4142 return t1; 4143 } 4144 //where 4145 public Type glb(Type t, Type s) { 4146 if (s == null) 4147 return t; 4148 else if (t.isPrimitive() || s.isPrimitive()) 4149 return syms.errType; 4150 else if (isSubtypeNoCapture(t, s)) 4151 return t; 4152 else if (isSubtypeNoCapture(s, t)) 4153 return s; 4154 4155 List<Type> closure = union(closure(t), closure(s)); 4156 return glbFlattened(closure, t); 4157 } 4158 //where 4159 /** 4160 * Perform glb for a list of non-primitive, non-error, non-compound types; 4161 * redundant elements are removed. Bounds should be ordered according to 4162 * {@link Symbol#precedes(TypeSymbol,Types)}. 4163 * 4164 * @param flatBounds List of type to glb 4165 * @param errT Original type to use if the result is an error type 4166 */ 4167 private Type glbFlattened(List<Type> flatBounds, Type errT) { 4168 List<Type> bounds = closureMin(flatBounds); 4169 4170 if (bounds.isEmpty()) { // length == 0 4171 return syms.objectType; 4172 } else if (bounds.tail.isEmpty()) { // length == 1 4173 return bounds.head; 4174 } else { // length > 1 4175 int classCount = 0; 4176 List<Type> cvars = List.nil(); 4177 List<Type> lowers = List.nil(); 4178 for (Type bound : bounds) { 4179 if (!bound.isInterface()) { 4180 classCount++; 4181 Type lower = cvarLowerBound(bound); 4182 if (bound != lower && !lower.hasTag(BOT)) { 4183 cvars = cvars.append(bound); 4184 lowers = lowers.append(lower); 4185 } 4186 } 4187 } 4188 if (classCount > 1) { 4189 if (lowers.isEmpty()) { 4190 return createErrorType(errT); 4191 } else { 4192 // try again with lower bounds included instead of capture variables 4193 List<Type> newBounds = bounds.diff(cvars).appendList(lowers); 4194 return glb(newBounds); 4195 } 4196 } 4197 } 4198 return makeIntersectionType(bounds); 4199 } 4200 // </editor-fold> 4201 4202 // <editor-fold defaultstate="collapsed" desc="hashCode"> 4203 /** 4204 * Compute a hash code on a type. 4205 */ 4206 public int hashCode(Type t) { 4207 return hashCode(t, false); 4208 } 4209 4210 public int hashCode(Type t, boolean strict) { 4211 return strict ? 4212 hashCodeStrictVisitor.visit(t) : 4213 hashCodeVisitor.visit(t); 4214 } 4215 // where 4216 private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor(); 4217 private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() { 4218 @Override 4219 public Integer visitTypeVar(TypeVar t, Void ignored) { 4220 return System.identityHashCode(t); 4221 } 4222 }; 4223 4224 private static class HashCodeVisitor extends UnaryVisitor<Integer> { 4225 public Integer visitType(Type t, Void ignored) { 4226 return t.getTag().ordinal(); 4227 } 4228 4229 @Override 4230 public Integer visitClassType(ClassType t, Void ignored) { 4231 int result = visit(t.getEnclosingType()); 4232 result *= 127; 4233 result += t.tsym.flatName().hashCode(); 4234 for (Type s : t.getTypeArguments()) { 4235 result *= 127; 4236 result += visit(s); 4237 } 4238 return result; 4239 } 4240 4241 @Override 4242 public Integer visitMethodType(MethodType t, Void ignored) { 4243 int h = METHOD.ordinal(); 4244 for (List<Type> thisargs = t.argtypes; 4245 thisargs.tail != null; 4246 thisargs = thisargs.tail) 4247 h = (h << 5) + visit(thisargs.head); 4248 return (h << 5) + visit(t.restype); 4249 } 4250 4251 @Override 4252 public Integer visitWildcardType(WildcardType t, Void ignored) { 4253 int result = t.kind.hashCode(); 4254 if (t.type != null) { 4255 result *= 127; 4256 result += visit(t.type); 4257 } 4258 return result; 4259 } 4260 4261 @Override 4262 public Integer visitArrayType(ArrayType t, Void ignored) { 4263 return visit(t.elemtype) + 12; 4264 } 4265 4266 @Override 4267 public Integer visitTypeVar(TypeVar t, Void ignored) { 4268 return System.identityHashCode(t); 4269 } 4270 4271 @Override 4272 public Integer visitUndetVar(UndetVar t, Void ignored) { 4273 return System.identityHashCode(t); 4274 } 4275 4276 @Override 4277 public Integer visitErrorType(ErrorType t, Void ignored) { 4278 return 0; 4279 } 4280 } 4281 // </editor-fold> 4282 4283 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable"> 4284 /** 4285 * Does t have a result that is a subtype of the result type of s, 4286 * suitable for covariant returns? It is assumed that both types 4287 * are (possibly polymorphic) method types. Monomorphic method 4288 * types are handled in the obvious way. Polymorphic method types 4289 * require renaming all type variables of one to corresponding 4290 * type variables in the other, where correspondence is by 4291 * position in the type parameter list. */ 4292 public boolean resultSubtype(Type t, Type s, Warner warner) { 4293 List<Type> tvars = t.getTypeArguments(); 4294 List<Type> svars = s.getTypeArguments(); 4295 Type tres = t.getReturnType(); 4296 Type sres = subst(s.getReturnType(), svars, tvars); 4297 return covariantReturnType(tres, sres, warner); 4298 } 4299 4300 /** 4301 * Return-Type-Substitutable. 4302 * @jls 8.4.5 Method Result 4303 */ 4304 public boolean returnTypeSubstitutable(Type r1, Type r2) { 4305 if (hasSameArgs(r1, r2)) 4306 return resultSubtype(r1, r2, noWarnings); 4307 else 4308 return covariantReturnType(r1.getReturnType(), 4309 erasure(r2.getReturnType()), 4310 noWarnings); 4311 } 4312 4313 public boolean returnTypeSubstitutable(Type r1, 4314 Type r2, Type r2res, 4315 Warner warner) { 4316 if (isSameType(r1.getReturnType(), r2res)) 4317 return true; 4318 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive()) 4319 return false; 4320 4321 if (hasSameArgs(r1, r2)) 4322 return covariantReturnType(r1.getReturnType(), r2res, warner); 4323 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner)) 4324 return true; 4325 if (!isSubtype(r1.getReturnType(), erasure(r2res))) 4326 return false; 4327 warner.warn(LintCategory.UNCHECKED); 4328 return true; 4329 } 4330 4331 /** 4332 * Is t an appropriate return type in an overrider for a 4333 * method that returns s? 4334 */ 4335 public boolean covariantReturnType(Type t, Type s, Warner warner) { 4336 return 4337 isSameType(t, s) || 4338 !t.isPrimitive() && 4339 !s.isPrimitive() && 4340 isAssignable(t, s, warner); 4341 } 4342 // </editor-fold> 4343 4344 // <editor-fold defaultstate="collapsed" desc="Box/unbox support"> 4345 /** 4346 * Return the class that boxes the given primitive. 4347 */ 4348 public ClassSymbol boxedClass(Type t) { 4349 return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]); 4350 } 4351 4352 /** 4353 * Return the boxed type if 't' is primitive, otherwise return 't' itself. 4354 */ 4355 public Type boxedTypeOrType(Type t) { 4356 return t.isPrimitive() ? 4357 boxedClass(t).type : 4358 t; 4359 } 4360 4361 /** 4362 * Return the primitive type corresponding to a boxed type. 4363 */ 4364 public Type unboxedType(Type t) { 4365 for (int i=0; i<syms.boxedName.length; i++) { 4366 Name box = syms.boxedName[i]; 4367 if (box != null && 4368 asSuper(t, syms.enterClass(syms.java_base, box)) != null) 4369 return syms.typeOfTag[i]; 4370 } 4371 return Type.noType; 4372 } 4373 4374 /** 4375 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself. 4376 */ 4377 public Type unboxedTypeOrType(Type t) { 4378 Type unboxedType = unboxedType(t); 4379 return unboxedType.hasTag(NONE) ? t : unboxedType; 4380 } 4381 // </editor-fold> 4382 4383 // <editor-fold defaultstate="collapsed" desc="Capture conversion"> 4384 /* 4385 * JLS 5.1.10 Capture Conversion: 4386 * 4387 * Let G name a generic type declaration with n formal type 4388 * parameters A1 ... An with corresponding bounds U1 ... Un. There 4389 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>, 4390 * where, for 1 <= i <= n: 4391 * 4392 * + If Ti is a wildcard type argument (4.5.1) of the form ? then 4393 * Si is a fresh type variable whose upper bound is 4394 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null 4395 * type. 4396 * 4397 * + If Ti is a wildcard type argument of the form ? extends Bi, 4398 * then Si is a fresh type variable whose upper bound is 4399 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is 4400 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is 4401 * a compile-time error if for any two classes (not interfaces) 4402 * Vi and Vj,Vi is not a subclass of Vj or vice versa. 4403 * 4404 * + If Ti is a wildcard type argument of the form ? super Bi, 4405 * then Si is a fresh type variable whose upper bound is 4406 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi. 4407 * 4408 * + Otherwise, Si = Ti. 4409 * 4410 * Capture conversion on any type other than a parameterized type 4411 * (4.5) acts as an identity conversion (5.1.1). Capture 4412 * conversions never require a special action at run time and 4413 * therefore never throw an exception at run time. 4414 * 4415 * Capture conversion is not applied recursively. 4416 */ 4417 /** 4418 * Capture conversion as specified by the JLS. 4419 */ 4420 4421 public List<Type> capture(List<Type> ts) { 4422 List<Type> buf = List.nil(); 4423 for (Type t : ts) { 4424 buf = buf.prepend(capture(t)); 4425 } 4426 return buf.reverse(); 4427 } 4428 4429 public Type capture(Type t) { 4430 if (!t.hasTag(CLASS)) { 4431 return t; 4432 } 4433 if (t.getEnclosingType() != Type.noType) { 4434 Type capturedEncl = capture(t.getEnclosingType()); 4435 if (capturedEncl != t.getEnclosingType()) { 4436 Type type1 = memberType(capturedEncl, t.tsym); 4437 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments()); 4438 } 4439 } 4440 ClassType cls = (ClassType)t; 4441 if (cls.isRaw() || !cls.isParameterized()) 4442 return cls; 4443 4444 ClassType G = (ClassType)cls.asElement().asType(); 4445 List<Type> A = G.getTypeArguments(); 4446 List<Type> T = cls.getTypeArguments(); 4447 List<Type> S = freshTypeVariables(T); 4448 4449 List<Type> currentA = A; 4450 List<Type> currentT = T; 4451 List<Type> currentS = S; 4452 boolean captured = false; 4453 while (!currentA.isEmpty() && 4454 !currentT.isEmpty() && 4455 !currentS.isEmpty()) { 4456 if (currentS.head != currentT.head) { 4457 captured = true; 4458 WildcardType Ti = (WildcardType)currentT.head; 4459 Type Ui = currentA.head.getUpperBound(); 4460 CapturedType Si = (CapturedType)currentS.head; 4461 if (Ui == null) 4462 Ui = syms.objectType; 4463 switch (Ti.kind) { 4464 case UNBOUND: 4465 Si.setUpperBound( subst(Ui, A, S) ); 4466 Si.lower = syms.botType; 4467 break; 4468 case EXTENDS: 4469 Si.setUpperBound( glb(Ti.getExtendsBound(), subst(Ui, A, S)) ); 4470 Si.lower = syms.botType; 4471 break; 4472 case SUPER: 4473 Si.setUpperBound( subst(Ui, A, S) ); 4474 Si.lower = Ti.getSuperBound(); 4475 break; 4476 } 4477 Type tmpBound = Si.getUpperBound().hasTag(UNDETVAR) ? ((UndetVar)Si.getUpperBound()).qtype : Si.getUpperBound(); 4478 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower; 4479 if (!Si.getUpperBound().hasTag(ERROR) && 4480 !Si.lower.hasTag(ERROR) && 4481 isSameType(tmpBound, tmpLower)) { 4482 currentS.head = Si.getUpperBound(); 4483 } 4484 } 4485 currentA = currentA.tail; 4486 currentT = currentT.tail; 4487 currentS = currentS.tail; 4488 } 4489 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty()) 4490 return erasure(t); // some "rare" type involved 4491 4492 if (captured) 4493 return new ClassType(cls.getEnclosingType(), S, cls.tsym, 4494 cls.getMetadata()); 4495 else 4496 return t; 4497 } 4498 // where 4499 public List<Type> freshTypeVariables(List<Type> types) { 4500 ListBuffer<Type> result = new ListBuffer<>(); 4501 for (Type t : types) { 4502 if (t.hasTag(WILDCARD)) { 4503 Type bound = ((WildcardType)t).getExtendsBound(); 4504 if (bound == null) 4505 bound = syms.objectType; 4506 result.append(new CapturedType(capturedName, 4507 syms.noSymbol, 4508 bound, 4509 syms.botType, 4510 (WildcardType)t)); 4511 } else { 4512 result.append(t); 4513 } 4514 } 4515 return result.toList(); 4516 } 4517 // </editor-fold> 4518 4519 // <editor-fold defaultstate="collapsed" desc="Internal utility methods"> 4520 private boolean sideCast(Type from, Type to, Warner warn) { 4521 // We are casting from type $from$ to type $to$, which are 4522 // non-final unrelated types. This method 4523 // tries to reject a cast by transferring type parameters 4524 // from $to$ to $from$ by common superinterfaces. 4525 boolean reverse = false; 4526 Type target = to; 4527 if ((to.tsym.flags() & INTERFACE) == 0) { 4528 Assert.check((from.tsym.flags() & INTERFACE) != 0); 4529 reverse = true; 4530 to = from; 4531 from = target; 4532 } 4533 List<Type> commonSupers = superClosure(to, erasure(from)); 4534 boolean giveWarning = commonSupers.isEmpty(); 4535 // The arguments to the supers could be unified here to 4536 // get a more accurate analysis 4537 while (commonSupers.nonEmpty()) { 4538 Type t1 = asSuper(from, commonSupers.head.tsym); 4539 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym); 4540 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments())) 4541 return false; 4542 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)); 4543 commonSupers = commonSupers.tail; 4544 } 4545 if (giveWarning && !isReifiable(reverse ? from : to)) 4546 warn.warn(LintCategory.UNCHECKED); 4547 return true; 4548 } 4549 4550 private boolean sideCastFinal(Type from, Type to, Warner warn) { 4551 // We are casting from type $from$ to type $to$, which are 4552 // unrelated types one of which is final and the other of 4553 // which is an interface. This method 4554 // tries to reject a cast by transferring type parameters 4555 // from the final class to the interface. 4556 boolean reverse = false; 4557 Type target = to; 4558 if ((to.tsym.flags() & INTERFACE) == 0) { 4559 Assert.check((from.tsym.flags() & INTERFACE) != 0); 4560 reverse = true; 4561 to = from; 4562 from = target; 4563 } 4564 Assert.check((from.tsym.flags() & FINAL) != 0); 4565 Type t1 = asSuper(from, to.tsym); 4566 if (t1 == null) return false; 4567 Type t2 = to; 4568 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments())) 4569 return false; 4570 if (!isReifiable(target) && 4571 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2))) 4572 warn.warn(LintCategory.UNCHECKED); 4573 return true; 4574 } 4575 4576 private boolean giveWarning(Type from, Type to) { 4577 List<Type> bounds = to.isCompound() ? 4578 directSupertypes(to) : List.of(to); 4579 for (Type b : bounds) { 4580 Type subFrom = asSub(from, b.tsym); 4581 if (b.isParameterized() && 4582 (!(isUnbounded(b) || 4583 isSubtype(from, b) || 4584 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) { 4585 return true; 4586 } 4587 } 4588 return false; 4589 } 4590 4591 private List<Type> superClosure(Type t, Type s) { 4592 List<Type> cl = List.nil(); 4593 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) { 4594 if (isSubtype(s, erasure(l.head))) { 4595 cl = insert(cl, l.head); 4596 } else { 4597 cl = union(cl, superClosure(l.head, s)); 4598 } 4599 } 4600 return cl; 4601 } 4602 4603 private boolean containsTypeEquivalent(Type t, Type s) { 4604 return isSameType(t, s) || // shortcut 4605 containsType(t, s) && containsType(s, t); 4606 } 4607 4608 // <editor-fold defaultstate="collapsed" desc="adapt"> 4609 /** 4610 * Adapt a type by computing a substitution which maps a source 4611 * type to a target type. 4612 * 4613 * @param source the source type 4614 * @param target the target type 4615 * @param from the type variables of the computed substitution 4616 * @param to the types of the computed substitution. 4617 */ 4618 public void adapt(Type source, 4619 Type target, 4620 ListBuffer<Type> from, 4621 ListBuffer<Type> to) throws AdaptFailure { 4622 new Adapter(from, to).adapt(source, target); 4623 } 4624 4625 class Adapter extends SimpleVisitor<Void, Type> { 4626 4627 ListBuffer<Type> from; 4628 ListBuffer<Type> to; 4629 Map<Symbol,Type> mapping; 4630 4631 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) { 4632 this.from = from; 4633 this.to = to; 4634 mapping = new HashMap<>(); 4635 } 4636 4637 public void adapt(Type source, Type target) throws AdaptFailure { 4638 visit(source, target); 4639 List<Type> fromList = from.toList(); 4640 List<Type> toList = to.toList(); 4641 while (!fromList.isEmpty()) { 4642 Type val = mapping.get(fromList.head.tsym); 4643 if (toList.head != val) 4644 toList.head = val; 4645 fromList = fromList.tail; 4646 toList = toList.tail; 4647 } 4648 } 4649 4650 @Override 4651 public Void visitClassType(ClassType source, Type target) throws AdaptFailure { 4652 if (target.hasTag(CLASS)) 4653 adaptRecursive(source.allparams(), target.allparams()); 4654 return null; 4655 } 4656 4657 @Override 4658 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure { 4659 if (target.hasTag(ARRAY)) 4660 adaptRecursive(elemtype(source), elemtype(target)); 4661 return null; 4662 } 4663 4664 @Override 4665 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure { 4666 if (source.isExtendsBound()) 4667 adaptRecursive(wildUpperBound(source), wildUpperBound(target)); 4668 else if (source.isSuperBound()) 4669 adaptRecursive(wildLowerBound(source), wildLowerBound(target)); 4670 return null; 4671 } 4672 4673 @Override 4674 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure { 4675 // Check to see if there is 4676 // already a mapping for $source$, in which case 4677 // the old mapping will be merged with the new 4678 Type val = mapping.get(source.tsym); 4679 if (val != null) { 4680 if (val.isSuperBound() && target.isSuperBound()) { 4681 val = isSubtype(wildLowerBound(val), wildLowerBound(target)) 4682 ? target : val; 4683 } else if (val.isExtendsBound() && target.isExtendsBound()) { 4684 val = isSubtype(wildUpperBound(val), wildUpperBound(target)) 4685 ? val : target; 4686 } else if (!isSameType(val, target)) { 4687 throw new AdaptFailure(); 4688 } 4689 } else { 4690 val = target; 4691 from.append(source); 4692 to.append(target); 4693 } 4694 mapping.put(source.tsym, val); 4695 return null; 4696 } 4697 4698 @Override 4699 public Void visitType(Type source, Type target) { 4700 return null; 4701 } 4702 4703 private Set<TypePair> cache = new HashSet<>(); 4704 4705 private void adaptRecursive(Type source, Type target) { 4706 TypePair pair = new TypePair(source, target); 4707 if (cache.add(pair)) { 4708 try { 4709 visit(source, target); 4710 } finally { 4711 cache.remove(pair); 4712 } 4713 } 4714 } 4715 4716 private void adaptRecursive(List<Type> source, List<Type> target) { 4717 if (source.length() == target.length()) { 4718 while (source.nonEmpty()) { 4719 adaptRecursive(source.head, target.head); 4720 source = source.tail; 4721 target = target.tail; 4722 } 4723 } 4724 } 4725 } 4726 4727 public static class AdaptFailure extends RuntimeException { 4728 static final long serialVersionUID = -7490231548272701566L; 4729 } 4730 4731 private void adaptSelf(Type t, 4732 ListBuffer<Type> from, 4733 ListBuffer<Type> to) { 4734 try { 4735 //if (t.tsym.type != t) 4736 adapt(t.tsym.type, t, from, to); 4737 } catch (AdaptFailure ex) { 4738 // Adapt should never fail calculating a mapping from 4739 // t.tsym.type to t as there can be no merge problem. 4740 throw new AssertionError(ex); 4741 } 4742 } 4743 // </editor-fold> 4744 4745 /** 4746 * Rewrite all type variables (universal quantifiers) in the given 4747 * type to wildcards (existential quantifiers). This is used to 4748 * determine if a cast is allowed. For example, if high is true 4749 * and {@code T <: Number}, then {@code List<T>} is rewritten to 4750 * {@code List<? extends Number>}. Since {@code List<Integer> <: 4751 * List<? extends Number>} a {@code List<T>} can be cast to {@code 4752 * List<Integer>} with a warning. 4753 * @param t a type 4754 * @param high if true return an upper bound; otherwise a lower 4755 * bound 4756 * @param rewriteTypeVars only rewrite captured wildcards if false; 4757 * otherwise rewrite all type variables 4758 * @return the type rewritten with wildcards (existential 4759 * quantifiers) only 4760 */ 4761 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) { 4762 return new Rewriter(high, rewriteTypeVars).visit(t); 4763 } 4764 4765 class Rewriter extends UnaryVisitor<Type> { 4766 4767 boolean high; 4768 boolean rewriteTypeVars; 4769 4770 Rewriter(boolean high, boolean rewriteTypeVars) { 4771 this.high = high; 4772 this.rewriteTypeVars = rewriteTypeVars; 4773 } 4774 4775 @Override 4776 public Type visitClassType(ClassType t, Void s) { 4777 ListBuffer<Type> rewritten = new ListBuffer<>(); 4778 boolean changed = false; 4779 for (Type arg : t.allparams()) { 4780 Type bound = visit(arg); 4781 if (arg != bound) { 4782 changed = true; 4783 } 4784 rewritten.append(bound); 4785 } 4786 if (changed) 4787 return subst(t.tsym.type, 4788 t.tsym.type.allparams(), 4789 rewritten.toList()); 4790 else 4791 return t; 4792 } 4793 4794 public Type visitType(Type t, Void s) { 4795 return t; 4796 } 4797 4798 @Override 4799 public Type visitCapturedType(CapturedType t, Void s) { 4800 Type w_bound = t.wildcard.type; 4801 Type bound = w_bound.contains(t) ? 4802 erasure(w_bound) : 4803 visit(w_bound); 4804 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind); 4805 } 4806 4807 @Override 4808 public Type visitTypeVar(TypeVar t, Void s) { 4809 if (rewriteTypeVars) { 4810 Type bound = t.getUpperBound().contains(t) ? 4811 erasure(t.getUpperBound()) : 4812 visit(t.getUpperBound()); 4813 return rewriteAsWildcardType(bound, t, EXTENDS); 4814 } else { 4815 return t; 4816 } 4817 } 4818 4819 @Override 4820 public Type visitWildcardType(WildcardType t, Void s) { 4821 Type bound2 = visit(t.type); 4822 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind); 4823 } 4824 4825 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) { 4826 switch (bk) { 4827 case EXTENDS: return high ? 4828 makeExtendsWildcard(B(bound), formal) : 4829 makeExtendsWildcard(syms.objectType, formal); 4830 case SUPER: return high ? 4831 makeSuperWildcard(syms.botType, formal) : 4832 makeSuperWildcard(B(bound), formal); 4833 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal); 4834 default: 4835 Assert.error("Invalid bound kind " + bk); 4836 return null; 4837 } 4838 } 4839 4840 Type B(Type t) { 4841 while (t.hasTag(WILDCARD)) { 4842 WildcardType w = (WildcardType)t; 4843 t = high ? 4844 w.getExtendsBound() : 4845 w.getSuperBound(); 4846 if (t == null) { 4847 t = high ? syms.objectType : syms.botType; 4848 } 4849 } 4850 return t; 4851 } 4852 } 4853 4854 4855 /** 4856 * Create a wildcard with the given upper (extends) bound; create 4857 * an unbounded wildcard if bound is Object. 4858 * 4859 * @param bound the upper bound 4860 * @param formal the formal type parameter that will be 4861 * substituted by the wildcard 4862 */ 4863 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) { 4864 if (bound == syms.objectType) { 4865 return new WildcardType(syms.objectType, 4866 BoundKind.UNBOUND, 4867 syms.boundClass, 4868 formal); 4869 } else { 4870 return new WildcardType(bound, 4871 BoundKind.EXTENDS, 4872 syms.boundClass, 4873 formal); 4874 } 4875 } 4876 4877 /** 4878 * Create a wildcard with the given lower (super) bound; create an 4879 * unbounded wildcard if bound is bottom (type of {@code null}). 4880 * 4881 * @param bound the lower bound 4882 * @param formal the formal type parameter that will be 4883 * substituted by the wildcard 4884 */ 4885 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) { 4886 if (bound.hasTag(BOT)) { 4887 return new WildcardType(syms.objectType, 4888 BoundKind.UNBOUND, 4889 syms.boundClass, 4890 formal); 4891 } else { 4892 return new WildcardType(bound, 4893 BoundKind.SUPER, 4894 syms.boundClass, 4895 formal); 4896 } 4897 } 4898 4899 /** 4900 * A wrapper for a type that allows use in sets. 4901 */ 4902 public static class UniqueType { 4903 public final Type type; 4904 final Types types; 4905 private boolean encodeTypeSig; 4906 4907 public UniqueType(Type type, Types types, boolean encodeTypeSig) { 4908 this.type = type; 4909 this.types = types; 4910 this.encodeTypeSig = encodeTypeSig; 4911 } 4912 4913 public UniqueType(Type type, Types types) { 4914 this(type, types, true); 4915 } 4916 4917 public int hashCode() { 4918 return types.hashCode(type); 4919 } 4920 4921 public boolean equals(Object obj) { 4922 return (obj instanceof UniqueType) && 4923 types.isSameType(type, ((UniqueType)obj).type); 4924 } 4925 4926 public boolean encodeTypeSig() { 4927 return encodeTypeSig; 4928 } 4929 4930 public String toString() { 4931 return type.toString(); 4932 } 4933 4934 } 4935 // </editor-fold> 4936 4937 // <editor-fold defaultstate="collapsed" desc="Visitors"> 4938 /** 4939 * A default visitor for types. All visitor methods except 4940 * visitType are implemented by delegating to visitType. Concrete 4941 * subclasses must provide an implementation of visitType and can 4942 * override other methods as needed. 4943 * 4944 * @param <R> the return type of the operation implemented by this 4945 * visitor; use Void if no return type is needed. 4946 * @param <S> the type of the second argument (the first being the 4947 * type itself) of the operation implemented by this visitor; use 4948 * Void if a second argument is not needed. 4949 */ 4950 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> { 4951 final public R visit(Type t, S s) { return t.accept(this, s); } 4952 public R visitClassType(ClassType t, S s) { return visitType(t, s); } 4953 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); } 4954 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); } 4955 public R visitMethodType(MethodType t, S s) { return visitType(t, s); } 4956 public R visitPackageType(PackageType t, S s) { return visitType(t, s); } 4957 public R visitModuleType(ModuleType t, S s) { return visitType(t, s); } 4958 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); } 4959 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); } 4960 public R visitForAll(ForAll t, S s) { return visitType(t, s); } 4961 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); } 4962 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); } 4963 } 4964 4965 /** 4966 * A default visitor for symbols. All visitor methods except 4967 * visitSymbol are implemented by delegating to visitSymbol. Concrete 4968 * subclasses must provide an implementation of visitSymbol and can 4969 * override other methods as needed. 4970 * 4971 * @param <R> the return type of the operation implemented by this 4972 * visitor; use Void if no return type is needed. 4973 * @param <S> the type of the second argument (the first being the 4974 * symbol itself) of the operation implemented by this visitor; use 4975 * Void if a second argument is not needed. 4976 */ 4977 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> { 4978 final public R visit(Symbol s, S arg) { return s.accept(this, arg); } 4979 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); } 4980 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); } 4981 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); } 4982 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); } 4983 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); } 4984 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); } 4985 } 4986 4987 /** 4988 * A <em>simple</em> visitor for types. This visitor is simple as 4989 * captured wildcards, for-all types (generic methods), and 4990 * undetermined type variables (part of inference) are hidden. 4991 * Captured wildcards are hidden by treating them as type 4992 * variables and the rest are hidden by visiting their qtypes. 4993 * 4994 * @param <R> the return type of the operation implemented by this 4995 * visitor; use Void if no return type is needed. 4996 * @param <S> the type of the second argument (the first being the 4997 * type itself) of the operation implemented by this visitor; use 4998 * Void if a second argument is not needed. 4999 */ 5000 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> { 5001 @Override 5002 public R visitCapturedType(CapturedType t, S s) { 5003 return visitTypeVar(t, s); 5004 } 5005 @Override 5006 public R visitForAll(ForAll t, S s) { 5007 return visit(t.qtype, s); 5008 } 5009 @Override 5010 public R visitUndetVar(UndetVar t, S s) { 5011 return visit(t.qtype, s); 5012 } 5013 } 5014 5015 /** 5016 * A plain relation on types. That is a 2-ary function on the 5017 * form Type × Type → Boolean. 5018 * <!-- In plain text: Type x Type -> Boolean --> 5019 */ 5020 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {} 5021 5022 /** 5023 * A convenience visitor for implementing operations that only 5024 * require one argument (the type itself), that is, unary 5025 * operations. 5026 * 5027 * @param <R> the return type of the operation implemented by this 5028 * visitor; use Void if no return type is needed. 5029 */ 5030 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> { 5031 final public R visit(Type t) { return t.accept(this, null); } 5032 } 5033 5034 /** 5035 * A visitor for implementing a mapping from types to types. The 5036 * default behavior of this class is to implement the identity 5037 * mapping (mapping a type to itself). This can be overridden in 5038 * subclasses. 5039 * 5040 * @param <S> the type of the second argument (the first being the 5041 * type itself) of this mapping; use Void if a second argument is 5042 * not needed. 5043 */ 5044 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> { 5045 final public Type visit(Type t) { return t.accept(this, null); } 5046 public Type visitType(Type t, S s) { return t; } 5047 } 5048 5049 /** 5050 * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}. 5051 * This class implements the functional interface {@code Function}, that allows it to be used 5052 * fluently in stream-like processing. 5053 */ 5054 public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> { 5055 @Override 5056 public Type apply(Type type) { return visit(type); } 5057 5058 List<Type> visit(List<Type> ts, S s) { 5059 return ts.map(t -> visit(t, s)); 5060 } 5061 5062 @Override 5063 public Type visitCapturedType(CapturedType t, S s) { 5064 return visitTypeVar(t, s); 5065 } 5066 } 5067 // </editor-fold> 5068 5069 5070 // <editor-fold defaultstate="collapsed" desc="Annotation support"> 5071 5072 public RetentionPolicy getRetention(Attribute.Compound a) { 5073 return getRetention(a.type.tsym); 5074 } 5075 5076 public RetentionPolicy getRetention(TypeSymbol sym) { 5077 RetentionPolicy vis = RetentionPolicy.CLASS; // the default 5078 Attribute.Compound c = sym.attribute(syms.retentionType.tsym); 5079 if (c != null) { 5080 Attribute value = c.member(names.value); 5081 if (value != null && value instanceof Attribute.Enum) { 5082 Name levelName = ((Attribute.Enum)value).value.name; 5083 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE; 5084 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS; 5085 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME; 5086 else ;// /* fail soft */ throw new AssertionError(levelName); 5087 } 5088 } 5089 return vis; 5090 } 5091 // </editor-fold> 5092 5093 // <editor-fold defaultstate="collapsed" desc="Signature Generation"> 5094 5095 public static abstract class SignatureGenerator { 5096 5097 public static class InvalidSignatureException extends RuntimeException { 5098 private static final long serialVersionUID = 0; 5099 5100 private final transient Type type; 5101 5102 InvalidSignatureException(Type type) { 5103 this.type = type; 5104 } 5105 5106 public Type type() { 5107 return type; 5108 } 5109 } 5110 5111 private final Types types; 5112 5113 protected abstract void append(char ch); 5114 protected abstract void append(byte[] ba); 5115 protected abstract void append(Name name); 5116 protected void classReference(ClassSymbol c) { /* by default: no-op */ } 5117 5118 protected SignatureGenerator(Types types) { 5119 this.types = types; 5120 } 5121 5122 protected void reportIllegalSignature(Type t) { 5123 throw new InvalidSignatureException(t); 5124 } 5125 5126 /** 5127 * Assemble signature of given type in string buffer. 5128 */ 5129 public void assembleSig(Type type) { 5130 switch (type.getTag()) { 5131 case BYTE: 5132 append('B'); 5133 break; 5134 case SHORT: 5135 append('S'); 5136 break; 5137 case CHAR: 5138 append('C'); 5139 break; 5140 case INT: 5141 append('I'); 5142 break; 5143 case LONG: 5144 append('J'); 5145 break; 5146 case FLOAT: 5147 append('F'); 5148 break; 5149 case DOUBLE: 5150 append('D'); 5151 break; 5152 case BOOLEAN: 5153 append('Z'); 5154 break; 5155 case VOID: 5156 append('V'); 5157 break; 5158 case CLASS: 5159 if (type.isCompound()) { 5160 reportIllegalSignature(type); 5161 } 5162 if (types.isValue(type)) 5163 append('Q'); 5164 else 5165 append('L'); 5166 assembleClassSig(type); 5167 append(';'); 5168 break; 5169 case ARRAY: 5170 ArrayType at = (ArrayType) type; 5171 append('['); 5172 assembleSig(at.elemtype); 5173 break; 5174 case METHOD: 5175 MethodType mt = (MethodType) type; 5176 append('('); 5177 assembleSig(mt.argtypes); 5178 append(')'); 5179 assembleSig(mt.restype); 5180 if (hasTypeVar(mt.thrown)) { 5181 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) { 5182 append('^'); 5183 assembleSig(l.head); 5184 } 5185 } 5186 break; 5187 case WILDCARD: { 5188 Type.WildcardType ta = (Type.WildcardType) type; 5189 switch (ta.kind) { 5190 case SUPER: 5191 append('-'); 5192 assembleSig(ta.type); 5193 break; 5194 case EXTENDS: 5195 append('+'); 5196 assembleSig(ta.type); 5197 break; 5198 case UNBOUND: 5199 append('*'); 5200 break; 5201 default: 5202 throw new AssertionError(ta.kind); 5203 } 5204 break; 5205 } 5206 case TYPEVAR: 5207 if (((TypeVar)type).isCaptured()) { 5208 reportIllegalSignature(type); 5209 } 5210 append('T'); 5211 append(type.tsym.name); 5212 append(';'); 5213 break; 5214 case FORALL: 5215 Type.ForAll ft = (Type.ForAll) type; 5216 assembleParamsSig(ft.tvars); 5217 assembleSig(ft.qtype); 5218 break; 5219 default: 5220 throw new AssertionError("typeSig " + type.getTag()); 5221 } 5222 } 5223 5224 public boolean hasTypeVar(List<Type> l) { 5225 while (l.nonEmpty()) { 5226 if (l.head.hasTag(TypeTag.TYPEVAR)) { 5227 return true; 5228 } 5229 l = l.tail; 5230 } 5231 return false; 5232 } 5233 5234 public void assembleClassSig(Type type) { 5235 ClassType ct = (ClassType) type; 5236 ClassSymbol c = (ClassSymbol) ct.tsym; 5237 classReference(c); 5238 Type outer = ct.getEnclosingType(); 5239 if (outer.allparams().nonEmpty()) { 5240 boolean rawOuter = 5241 c.owner.kind == MTH || // either a local class 5242 c.name == types.names.empty; // or anonymous 5243 assembleClassSig(rawOuter 5244 ? types.erasure(outer) 5245 : outer); 5246 append(rawOuter ? '$' : '.'); 5247 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname)); 5248 append(rawOuter 5249 ? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength()) 5250 : c.name); 5251 } else { 5252 append(externalize(c.flatname)); 5253 } 5254 if (ct.getTypeArguments().nonEmpty()) { 5255 append('<'); 5256 assembleSig(ct.getTypeArguments()); 5257 append('>'); 5258 } 5259 } 5260 5261 public void assembleParamsSig(List<Type> typarams) { 5262 append('<'); 5263 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) { 5264 Type.TypeVar tvar = (Type.TypeVar) ts.head; 5265 append(tvar.tsym.name); 5266 List<Type> bounds = types.getBounds(tvar); 5267 if ((bounds.head.tsym.flags() & INTERFACE) != 0) { 5268 append(':'); 5269 } 5270 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) { 5271 append(':'); 5272 assembleSig(l.head); 5273 } 5274 } 5275 append('>'); 5276 } 5277 5278 public void assembleSig(List<Type> types) { 5279 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) { 5280 assembleSig(ts.head); 5281 } 5282 } 5283 } 5284 5285 public Type constantType(LoadableConstant c) { 5286 switch (c.poolTag()) { 5287 case ClassFile.CONSTANT_Class: 5288 return syms.classType; 5289 case ClassFile.CONSTANT_String: 5290 return syms.stringType; 5291 case ClassFile.CONSTANT_Integer: 5292 return syms.intType; 5293 case ClassFile.CONSTANT_Float: 5294 return syms.floatType; 5295 case ClassFile.CONSTANT_Long: 5296 return syms.longType; 5297 case ClassFile.CONSTANT_Double: 5298 return syms.doubleType; 5299 case ClassFile.CONSTANT_MethodHandle: 5300 return syms.methodHandleType; 5301 case ClassFile.CONSTANT_MethodType: 5302 return syms.methodTypeType; 5303 case ClassFile.CONSTANT_Dynamic: 5304 return ((DynamicVarSymbol)c).type; 5305 default: 5306 throw new AssertionError("Not a loadable constant: " + c.poolTag()); 5307 } 5308 } 5309 // </editor-fold> 5310 5311 public void newRound() { 5312 descCache._map.clear(); 5313 isDerivedRawCache.clear(); 5314 implCache._map.clear(); 5315 membersCache._map.clear(); 5316 closureCache.clear(); 5317 } 5318 }