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