1 /*
2 * Copyright (c) 2003, 2013, 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.Comparator;
30 import java.util.HashSet;
31 import java.util.HashMap;
32 import java.util.Locale;
33 import java.util.Map;
34 import java.util.Set;
35 import java.util.WeakHashMap;
36
37 import javax.lang.model.type.TypeKind;
38
39 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
40 import com.sun.tools.javac.code.Lint.LintCategory;
41 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
42 import com.sun.tools.javac.comp.Check;
43 import com.sun.tools.javac.jvm.ClassReader;
44 import com.sun.tools.javac.util.*;
45 import static com.sun.tools.javac.code.BoundKind.*;
46 import static com.sun.tools.javac.code.Flags.*;
47 import static com.sun.tools.javac.code.Scope.*;
48 import static com.sun.tools.javac.code.Symbol.*;
49 import static com.sun.tools.javac.code.Type.*;
50 import static com.sun.tools.javac.code.TypeTag.*;
51 import static com.sun.tools.javac.jvm.ClassFile.externalize;
52 import static com.sun.tools.javac.util.ListBuffer.lb;
53
54 /**
55 * Utility class containing various operations on types.
56 *
57 * <p>Unless other names are more illustrative, the following naming
58 * conventions should be observed in this file:
59 *
60 * <dl>
61 * <dt>t</dt>
62 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
63 * <dt>s</dt>
64 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
65 * <dt>ts</dt>
66 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
67 * <dt>ss</dt>
68 * <dd>A second list of types should be named ss.</dd>
69 * </dl>
70 *
71 * <p><b>This is NOT part of any supported API.
72 * If you write code that depends on this, you do so at your own risk.
73 * This code and its internal interfaces are subject to change or
74 * deletion without notice.</b>
75 */
76 public class Types {
77 protected static final Context.Key<Types> typesKey =
78 new Context.Key<Types>();
79
80 final Symtab syms;
81 final JavacMessages messages;
82 final Names names;
83 final boolean allowBoxing;
84 final boolean allowCovariantReturns;
85 final boolean allowObjectToPrimitiveCast;
86 final boolean allowDefaultMethods;
87 final ClassReader reader;
88 final Check chk;
89 JCDiagnostic.Factory diags;
90 List<Warner> warnStack = List.nil();
91 final Name capturedName;
92 private final FunctionDescriptorLookupError functionDescriptorLookupError;
93
94 public final Warner noWarnings;
95
96 // <editor-fold defaultstate="collapsed" desc="Instantiating">
97 public static Types instance(Context context) {
98 Types instance = context.get(typesKey);
99 if (instance == null)
100 instance = new Types(context);
101 return instance;
102 }
103
104 protected Types(Context context) {
105 context.put(typesKey, this);
106 syms = Symtab.instance(context);
107 names = Names.instance(context);
108 Source source = Source.instance(context);
109 allowBoxing = source.allowBoxing();
110 allowCovariantReturns = source.allowCovariantReturns();
111 allowObjectToPrimitiveCast = source.allowObjectToPrimitiveCast();
112 allowDefaultMethods = source.allowDefaultMethods();
113 reader = ClassReader.instance(context);
114 chk = Check.instance(context);
115 capturedName = names.fromString("<captured wildcard>");
116 messages = JavacMessages.instance(context);
117 diags = JCDiagnostic.Factory.instance(context);
118 functionDescriptorLookupError = new FunctionDescriptorLookupError();
119 noWarnings = new Warner(null);
120 }
121 // </editor-fold>
122
123 // <editor-fold defaultstate="collapsed" desc="upperBound">
124 /**
125 * The "rvalue conversion".<br>
126 * The upper bound of most types is the type
127 * itself. Wildcards, on the other hand have upper
128 * and lower bounds.
129 * @param t a type
130 * @return the upper bound of the given type
131 */
132 public Type upperBound(Type t) {
133 return upperBound.visit(t);
134 }
135 // where
136 private final MapVisitor<Void> upperBound = new MapVisitor<Void>() {
137
138 @Override
139 public Type visitWildcardType(WildcardType t, Void ignored) {
140 if (t.isSuperBound())
141 return t.bound == null ? syms.objectType : t.bound.bound;
142 else
143 return visit(t.type);
144 }
145
146 @Override
147 public Type visitCapturedType(CapturedType t, Void ignored) {
148 return visit(t.bound);
149 }
150 };
151 // </editor-fold>
152
153 // <editor-fold defaultstate="collapsed" desc="lowerBound">
154 /**
155 * The "lvalue conversion".<br>
156 * The lower bound of most types is the type
157 * itself. Wildcards, on the other hand have upper
158 * and lower bounds.
159 * @param t a type
160 * @return the lower bound of the given type
161 */
162 public Type lowerBound(Type t) {
163 return lowerBound.visit(t);
164 }
165 // where
166 private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() {
167
168 @Override
169 public Type visitWildcardType(WildcardType t, Void ignored) {
170 return t.isExtendsBound() ? syms.botType : visit(t.type);
171 }
172
173 @Override
174 public Type visitCapturedType(CapturedType t, Void ignored) {
175 return visit(t.getLowerBound());
176 }
177 };
178 // </editor-fold>
179
180 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
181 /**
182 * Checks that all the arguments to a class are unbounded
183 * wildcards or something else that doesn't make any restrictions
184 * on the arguments. If a class isUnbounded, a raw super- or
185 * subclass can be cast to it without a warning.
186 * @param t a type
187 * @return true iff the given type is unbounded or raw
188 */
189 public boolean isUnbounded(Type t) {
190 return isUnbounded.visit(t);
191 }
192 // where
193 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
194
195 public Boolean visitType(Type t, Void ignored) {
196 return true;
197 }
198
199 @Override
200 public Boolean visitClassType(ClassType t, Void ignored) {
201 List<Type> parms = t.tsym.type.allparams();
202 List<Type> args = t.allparams();
203 while (parms.nonEmpty()) {
204 WildcardType unb = new WildcardType(syms.objectType,
205 BoundKind.UNBOUND,
206 syms.boundClass,
207 (TypeVar)parms.head);
208 if (!containsType(args.head, unb))
209 return false;
210 parms = parms.tail;
211 args = args.tail;
212 }
213 return true;
214 }
215 };
216 // </editor-fold>
217
218 // <editor-fold defaultstate="collapsed" desc="asSub">
219 /**
220 * Return the least specific subtype of t that starts with symbol
221 * sym. If none exists, return null. The least specific subtype
222 * is determined as follows:
223 *
224 * <p>If there is exactly one parameterized instance of sym that is a
225 * subtype of t, that parameterized instance is returned.<br>
226 * Otherwise, if the plain type or raw type `sym' is a subtype of
227 * type t, the type `sym' itself is returned. Otherwise, null is
228 * returned.
229 */
230 public Type asSub(Type t, Symbol sym) {
231 return asSub.visit(t, sym);
232 }
233 // where
234 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
235
236 public Type visitType(Type t, Symbol sym) {
237 return null;
238 }
239
240 @Override
241 public Type visitClassType(ClassType t, Symbol sym) {
242 if (t.tsym == sym)
243 return t;
244 Type base = asSuper(sym.type, t.tsym);
245 if (base == null)
246 return null;
247 ListBuffer<Type> from = new ListBuffer<Type>();
248 ListBuffer<Type> to = new ListBuffer<Type>();
249 try {
250 adapt(base, t, from, to);
251 } catch (AdaptFailure ex) {
252 return null;
253 }
254 Type res = subst(sym.type, from.toList(), to.toList());
255 if (!isSubtype(res, t))
256 return null;
257 ListBuffer<Type> openVars = new ListBuffer<Type>();
258 for (List<Type> l = sym.type.allparams();
259 l.nonEmpty(); l = l.tail)
260 if (res.contains(l.head) && !t.contains(l.head))
261 openVars.append(l.head);
262 if (openVars.nonEmpty()) {
263 if (t.isRaw()) {
264 // The subtype of a raw type is raw
265 res = erasure(res);
266 } else {
267 // Unbound type arguments default to ?
268 List<Type> opens = openVars.toList();
269 ListBuffer<Type> qs = new ListBuffer<Type>();
270 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
271 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head));
272 }
273 res = subst(res, opens, qs.toList());
274 }
275 }
276 return res;
277 }
278
279 @Override
280 public Type visitErrorType(ErrorType t, Symbol sym) {
281 return t;
282 }
283 };
284 // </editor-fold>
285
286 // <editor-fold defaultstate="collapsed" desc="isConvertible">
287 /**
288 * Is t a subtype of or convertible via boxing/unboxing
289 * conversion to s?
290 */
291 public boolean isConvertible(Type t, Type s, Warner warn) {
292 if (t.tag == ERROR)
293 return true;
294 boolean tPrimitive = t.isPrimitive();
295 boolean sPrimitive = s.isPrimitive();
296 if (tPrimitive == sPrimitive) {
297 return isSubtypeUnchecked(t, s, warn);
298 }
299 if (!allowBoxing) return false;
300 return tPrimitive
301 ? isSubtype(boxedClass(t).type, s)
302 : isSubtype(unboxedType(t), s);
303 }
304
305 /**
306 * Is t a subtype of or convertiable via boxing/unboxing
307 * convertions to s?
308 */
309 public boolean isConvertible(Type t, Type s) {
310 return isConvertible(t, s, noWarnings);
311 }
312 // </editor-fold>
313
314 // <editor-fold defaultstate="collapsed" desc="findSam">
315
316 /**
317 * Exception used to report a function descriptor lookup failure. The exception
318 * wraps a diagnostic that can be used to generate more details error
319 * messages.
320 */
321 public static class FunctionDescriptorLookupError extends RuntimeException {
322 private static final long serialVersionUID = 0;
323
324 JCDiagnostic diagnostic;
325
326 FunctionDescriptorLookupError() {
327 this.diagnostic = null;
328 }
329
330 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
331 this.diagnostic = diag;
332 return this;
333 }
334
335 public JCDiagnostic getDiagnostic() {
336 return diagnostic;
337 }
338 }
339
340 /**
341 * A cache that keeps track of function descriptors associated with given
342 * functional interfaces.
343 */
344 class DescriptorCache {
345
346 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<TypeSymbol, Entry>();
347
348 class FunctionDescriptor {
349 Symbol descSym;
350
351 FunctionDescriptor(Symbol descSym) {
352 this.descSym = descSym;
353 }
354
355 public Symbol getSymbol() {
356 return descSym;
357 }
358
359 public Type getType(Type site) {
360 site = removeWildcards(site);
361 if (!chk.checkValidGenericType(site)) {
362 //if the inferred functional interface type is not well-formed,
363 //or if it's not a subtype of the original target, issue an error
364 throw failure(diags.fragment("no.suitable.functional.intf.inst", site));
365 }
366 return memberType(site, descSym);
367 }
368 }
369
370 class Entry {
371 final FunctionDescriptor cachedDescRes;
372 final int prevMark;
373
374 public Entry(FunctionDescriptor cachedDescRes,
375 int prevMark) {
376 this.cachedDescRes = cachedDescRes;
377 this.prevMark = prevMark;
378 }
379
380 boolean matches(int mark) {
381 return this.prevMark == mark;
382 }
383 }
384
385 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
386 Entry e = _map.get(origin);
387 CompoundScope members = membersClosure(origin.type, false);
388 if (e == null ||
389 !e.matches(members.getMark())) {
390 FunctionDescriptor descRes = findDescriptorInternal(origin, members);
391 _map.put(origin, new Entry(descRes, members.getMark()));
392 return descRes;
393 }
394 else {
395 return e.cachedDescRes;
396 }
397 }
398
399 /**
400 * Compute the function descriptor associated with a given functional interface
401 */
402 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin, CompoundScope membersCache) throws FunctionDescriptorLookupError {
403 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0) {
404 //t must be an interface
405 throw failure("not.a.functional.intf", origin);
406 }
407
408 final ListBuffer<Symbol> abstracts = ListBuffer.lb();
409 for (Symbol sym : membersCache.getElements(new DescriptorFilter(origin))) {
410 Type mtype = memberType(origin.type, sym);
411 if (abstracts.isEmpty() ||
412 (sym.name == abstracts.first().name &&
413 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
414 abstracts.append(sym);
415 } else {
416 //the target method(s) should be the only abstract members of t
417 throw failure("not.a.functional.intf.1", origin,
418 diags.fragment("incompatible.abstracts", Kinds.kindName(origin), origin));
419 }
420 }
421 if (abstracts.isEmpty()) {
422 //t must define a suitable non-generic method
423 throw failure("not.a.functional.intf.1", origin,
424 diags.fragment("no.abstracts", Kinds.kindName(origin), origin));
425 } else if (abstracts.size() == 1) {
426 return new FunctionDescriptor(abstracts.first());
427 } else { // size > 1
428 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
429 if (descRes == null) {
430 //we can get here if the functional interface is ill-formed
431 ListBuffer<JCDiagnostic> descriptors = ListBuffer.lb();
432 for (Symbol desc : abstracts) {
433 String key = desc.type.getThrownTypes().nonEmpty() ?
434 "descriptor.throws" : "descriptor";
435 descriptors.append(diags.fragment(key, desc.name,
436 desc.type.getParameterTypes(),
437 desc.type.getReturnType(),
438 desc.type.getThrownTypes()));
439 }
440 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
441 new JCDiagnostic.MultilineDiagnostic(diags.fragment("incompatible.descs.in.functional.intf",
442 Kinds.kindName(origin), origin), descriptors.toList());
443 throw failure(incompatibleDescriptors);
444 }
445 return descRes;
446 }
447 }
448
449 /**
450 * Compute a synthetic type for the target descriptor given a list
451 * of override-equivalent methods in the functional interface type.
452 * The resulting method type is a method type that is override-equivalent
453 * and return-type substitutable with each method in the original list.
454 */
455 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
456 //pick argument types - simply take the signature that is a
457 //subsignature of all other signatures in the list (as per JLS 8.4.2)
458 List<Symbol> mostSpecific = List.nil();
459 outer: for (Symbol msym1 : methodSyms) {
460 Type mt1 = memberType(origin.type, msym1);
461 for (Symbol msym2 : methodSyms) {
462 Type mt2 = memberType(origin.type, msym2);
463 if (!isSubSignature(mt1, mt2)) {
464 continue outer;
465 }
466 }
467 mostSpecific = mostSpecific.prepend(msym1);
468 }
469 if (mostSpecific.isEmpty()) {
470 return null;
471 }
472
473
474 //pick return types - this is done in two phases: (i) first, the most
475 //specific return type is chosen using strict subtyping; if this fails,
476 //a second attempt is made using return type substitutability (see JLS 8.4.5)
477 boolean phase2 = false;
478 Symbol bestSoFar = null;
479 while (bestSoFar == null) {
480 outer: for (Symbol msym1 : mostSpecific) {
481 Type mt1 = memberType(origin.type, msym1);
482 for (Symbol msym2 : methodSyms) {
483 Type mt2 = memberType(origin.type, msym2);
484 if (phase2 ?
485 !returnTypeSubstitutable(mt1, mt2) :
486 !isSubtypeInternal(mt1.getReturnType(), mt2.getReturnType())) {
487 continue outer;
488 }
489 }
490 bestSoFar = msym1;
491 }
492 if (phase2) {
493 break;
494 } else {
495 phase2 = true;
496 }
497 }
498 if (bestSoFar == null) return null;
499
500 //merge thrown types - form the intersection of all the thrown types in
501 //all the signatures in the list
502 List<Type> thrown = null;
503 for (Symbol msym1 : methodSyms) {
504 Type mt1 = memberType(origin.type, msym1);
505 thrown = (thrown == null) ?
506 mt1.getThrownTypes() :
507 chk.intersect(mt1.getThrownTypes(), thrown);
508 }
509
510 final List<Type> thrown1 = thrown;
511 return new FunctionDescriptor(bestSoFar) {
512 @Override
513 public Type getType(Type origin) {
514 Type mt = memberType(origin, getSymbol());
515 return createMethodTypeWithThrown(mt, thrown1);
516 }
517 };
518 }
519
520 boolean isSubtypeInternal(Type s, Type t) {
521 return (s.isPrimitive() && t.isPrimitive()) ?
522 isSameType(t, s) :
523 isSubtype(s, t);
524 }
525
526 FunctionDescriptorLookupError failure(String msg, Object... args) {
527 return failure(diags.fragment(msg, args));
528 }
529
530 FunctionDescriptorLookupError failure(JCDiagnostic diag) {
531 return functionDescriptorLookupError.setMessage(diag);
532 }
533 }
534
535 private DescriptorCache descCache = new DescriptorCache();
536
537 /**
538 * Find the method descriptor associated to this class symbol - if the
539 * symbol 'origin' is not a functional interface, an exception is thrown.
540 */
541 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
542 return descCache.get(origin).getSymbol();
543 }
544
545 /**
546 * Find the type of the method descriptor associated to this class symbol -
547 * if the symbol 'origin' is not a functional interface, an exception is thrown.
548 */
549 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
550 return descCache.get(origin.tsym).getType(origin);
551 }
552
553 /**
554 * Is given type a functional interface?
555 */
556 public boolean isFunctionalInterface(TypeSymbol tsym) {
557 try {
558 findDescriptorSymbol(tsym);
559 return true;
560 } catch (FunctionDescriptorLookupError ex) {
561 return false;
562 }
563 }
564
565 public boolean isFunctionalInterface(Type site) {
566 try {
567 findDescriptorType(site);
568 return true;
569 } catch (FunctionDescriptorLookupError ex) {
570 return false;
571 }
572 }
573
574 public Type removeWildcards(Type site) {
575 Type capturedSite = capture(site);
576 if (capturedSite != site) {
577 Type formalInterface = site.tsym.type;
578 ListBuffer<Type> typeargs = ListBuffer.lb();
579 List<Type> actualTypeargs = site.getTypeArguments();
580 List<Type> capturedTypeargs = capturedSite.getTypeArguments();
581 //simply replace the wildcards with its bound
582 for (Type t : formalInterface.getTypeArguments()) {
583 if (actualTypeargs.head.hasTag(WILDCARD)) {
584 WildcardType wt = (WildcardType)actualTypeargs.head;
585 Type bound;
586 switch (wt.kind) {
587 case EXTENDS:
588 case UNBOUND:
589 CapturedType capVar = (CapturedType)capturedTypeargs.head;
590 //use declared bound if it doesn't depend on formal type-args
591 bound = capVar.bound.containsAny(capturedSite.getTypeArguments()) ?
592 wt.type : capVar.bound;
593 break;
594 default:
595 bound = wt.type;
596 }
597 typeargs.append(bound);
598 } else {
599 typeargs.append(actualTypeargs.head);
600 }
601 actualTypeargs = actualTypeargs.tail;
602 capturedTypeargs = capturedTypeargs.tail;
603 }
604 return subst(formalInterface, formalInterface.getTypeArguments(), typeargs.toList());
605 } else {
606 return site;
607 }
608 }
609 // </editor-fold>
610
611 /**
612 * Scope filter used to skip methods that should be ignored (such as methods
613 * overridden by j.l.Object) during function interface conversion interface check
614 */
615 class DescriptorFilter implements Filter<Symbol> {
616
617 TypeSymbol origin;
618
619 DescriptorFilter(TypeSymbol origin) {
620 this.origin = origin;
621 }
622
623 @Override
624 public boolean accepts(Symbol sym) {
625 return sym.kind == Kinds.MTH &&
626 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
627 !overridesObjectMethod(origin, sym) &&
628 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
629 }
630 };
631
632 // <editor-fold defaultstate="collapsed" desc="isSubtype">
633 /**
634 * Is t an unchecked subtype of s?
635 */
636 public boolean isSubtypeUnchecked(Type t, Type s) {
637 return isSubtypeUnchecked(t, s, noWarnings);
638 }
639 /**
640 * Is t an unchecked subtype of s?
641 */
642 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
643 boolean result = isSubtypeUncheckedInternal(t, s, warn);
644 if (result) {
645 checkUnsafeVarargsConversion(t, s, warn);
646 }
647 return result;
648 }
649 //where
650 private boolean isSubtypeUncheckedInternal(Type t, Type s, Warner warn) {
651 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
652 t = t.unannotatedType();
653 s = s.unannotatedType();
654 if (((ArrayType)t).elemtype.isPrimitive()) {
655 return isSameType(elemtype(t), elemtype(s));
656 } else {
657 return isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
658 }
659 } else if (isSubtype(t, s)) {
660 return true;
661 }
662 else if (t.tag == TYPEVAR) {
663 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
664 }
665 else if (!s.isRaw()) {
666 Type t2 = asSuper(t, s.tsym);
667 if (t2 != null && t2.isRaw()) {
668 if (isReifiable(s))
669 warn.silentWarn(LintCategory.UNCHECKED);
670 else
671 warn.warn(LintCategory.UNCHECKED);
672 return true;
673 }
674 }
675 return false;
676 }
677
678 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
679 if (t.tag != ARRAY || isReifiable(t))
680 return;
681 t = t.unannotatedType();
682 s = s.unannotatedType();
683 ArrayType from = (ArrayType)t;
684 boolean shouldWarn = false;
685 switch (s.tag) {
686 case ARRAY:
687 ArrayType to = (ArrayType)s;
688 shouldWarn = from.isVarargs() &&
689 !to.isVarargs() &&
690 !isReifiable(from);
691 break;
692 case CLASS:
693 shouldWarn = from.isVarargs();
694 break;
695 }
696 if (shouldWarn) {
697 warn.warn(LintCategory.VARARGS);
698 }
699 }
700
701 /**
702 * Is t a subtype of s?<br>
703 * (not defined for Method and ForAll types)
704 */
705 final public boolean isSubtype(Type t, Type s) {
706 return isSubtype(t, s, true);
707 }
708 final public boolean isSubtypeNoCapture(Type t, Type s) {
709 return isSubtype(t, s, false);
710 }
711 public boolean isSubtype(Type t, Type s, boolean capture) {
712 if (t == s)
713 return true;
714
715 t = t.unannotatedType();
716 s = s.unannotatedType();
717
718 if (t == s)
719 return true;
720
721 if (s.isPartial())
722 return isSuperType(s, t);
723
724 if (s.isCompound()) {
725 for (Type s2 : interfaces(s).prepend(supertype(s))) {
726 if (!isSubtype(t, s2, capture))
727 return false;
728 }
729 return true;
730 }
731
732 Type lower = lowerBound(s);
733 if (s != lower)
734 return isSubtype(capture ? capture(t) : t, lower, false);
735
736 return isSubtype.visit(capture ? capture(t) : t, s);
737 }
738 // where
739 private TypeRelation isSubtype = new TypeRelation()
740 {
741 public Boolean visitType(Type t, Type s) {
742 switch (t.tag) {
743 case BYTE:
744 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
745 case CHAR:
746 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
747 case SHORT: case INT: case LONG:
748 case FLOAT: case DOUBLE:
749 return t.getTag().isSubRangeOf(s.getTag());
750 case BOOLEAN: case VOID:
751 return t.hasTag(s.getTag());
752 case TYPEVAR:
753 return isSubtypeNoCapture(t.getUpperBound(), s);
754 case BOT:
755 return
756 s.hasTag(BOT) || s.hasTag(CLASS) ||
757 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
758 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
759 case NONE:
760 return false;
761 default:
762 throw new AssertionError("isSubtype " + t.tag);
763 }
764 }
765
766 private Set<TypePair> cache = new HashSet<TypePair>();
767
768 private boolean containsTypeRecursive(Type t, Type s) {
769 TypePair pair = new TypePair(t, s);
770 if (cache.add(pair)) {
771 try {
772 return containsType(t.getTypeArguments(),
773 s.getTypeArguments());
774 } finally {
775 cache.remove(pair);
776 }
777 } else {
778 return containsType(t.getTypeArguments(),
779 rewriteSupers(s).getTypeArguments());
780 }
781 }
782
783 private Type rewriteSupers(Type t) {
784 if (!t.isParameterized())
785 return t;
786 ListBuffer<Type> from = lb();
787 ListBuffer<Type> to = lb();
788 adaptSelf(t, from, to);
789 if (from.isEmpty())
790 return t;
791 ListBuffer<Type> rewrite = lb();
792 boolean changed = false;
793 for (Type orig : to.toList()) {
794 Type s = rewriteSupers(orig);
795 if (s.isSuperBound() && !s.isExtendsBound()) {
796 s = new WildcardType(syms.objectType,
797 BoundKind.UNBOUND,
798 syms.boundClass);
799 changed = true;
800 } else if (s != orig) {
801 s = new WildcardType(upperBound(s),
802 BoundKind.EXTENDS,
803 syms.boundClass);
804 changed = true;
805 }
806 rewrite.append(s);
807 }
808 if (changed)
809 return subst(t.tsym.type, from.toList(), rewrite.toList());
810 else
811 return t;
812 }
813
814 @Override
815 public Boolean visitClassType(ClassType t, Type s) {
816 Type sup = asSuper(t, s.tsym);
817 return sup != null
818 && sup.tsym == s.tsym
819 // You're not allowed to write
820 // Vector<Object> vec = new Vector<String>();
821 // But with wildcards you can write
822 // Vector<? extends Object> vec = new Vector<String>();
823 // which means that subtype checking must be done
824 // here instead of same-type checking (via containsType).
825 && (!s.isParameterized() || containsTypeRecursive(s, sup))
826 && isSubtypeNoCapture(sup.getEnclosingType(),
827 s.getEnclosingType());
828 }
829
830 @Override
831 public Boolean visitArrayType(ArrayType t, Type s) {
832 if (s.tag == ARRAY) {
833 if (t.elemtype.isPrimitive())
834 return isSameType(t.elemtype, elemtype(s));
835 else
836 return isSubtypeNoCapture(t.elemtype, elemtype(s));
837 }
838
839 if (s.tag == CLASS) {
840 Name sname = s.tsym.getQualifiedName();
841 return sname == names.java_lang_Object
842 || sname == names.java_lang_Cloneable
843 || sname == names.java_io_Serializable;
844 }
845
846 return false;
847 }
848
849 @Override
850 public Boolean visitUndetVar(UndetVar t, Type s) {
851 //todo: test against origin needed? or replace with substitution?
852 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN) {
853 return true;
854 } else if (s.tag == BOT) {
855 //if 's' is 'null' there's no instantiated type U for which
856 //U <: s (but 'null' itself, which is not a valid type)
857 return false;
858 }
859
860 t.addBound(InferenceBound.UPPER, s, Types.this);
861 return true;
862 }
863
864 @Override
865 public Boolean visitErrorType(ErrorType t, Type s) {
866 return true;
867 }
868 };
869
870 /**
871 * Is t a subtype of every type in given list `ts'?<br>
872 * (not defined for Method and ForAll types)<br>
873 * Allows unchecked conversions.
874 */
875 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
876 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
877 if (!isSubtypeUnchecked(t, l.head, warn))
878 return false;
879 return true;
880 }
881
882 /**
883 * Are corresponding elements of ts subtypes of ss? If lists are
884 * of different length, return false.
885 */
886 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
887 while (ts.tail != null && ss.tail != null
888 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
889 isSubtype(ts.head, ss.head)) {
890 ts = ts.tail;
891 ss = ss.tail;
892 }
893 return ts.tail == null && ss.tail == null;
894 /*inlined: ts.isEmpty() && ss.isEmpty();*/
895 }
896
897 /**
898 * Are corresponding elements of ts subtypes of ss, allowing
899 * unchecked conversions? If lists are of different length,
900 * return false.
901 **/
902 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
903 while (ts.tail != null && ss.tail != null
904 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
905 isSubtypeUnchecked(ts.head, ss.head, warn)) {
906 ts = ts.tail;
907 ss = ss.tail;
908 }
909 return ts.tail == null && ss.tail == null;
910 /*inlined: ts.isEmpty() && ss.isEmpty();*/
911 }
912 // </editor-fold>
913
914 // <editor-fold defaultstate="collapsed" desc="isSuperType">
915 /**
916 * Is t a supertype of s?
917 */
918 public boolean isSuperType(Type t, Type s) {
919 switch (t.tag) {
920 case ERROR:
921 return true;
922 case UNDETVAR: {
923 UndetVar undet = (UndetVar)t;
924 if (t == s ||
925 undet.qtype == s ||
926 s.tag == ERROR ||
927 s.tag == BOT) return true;
928 undet.addBound(InferenceBound.LOWER, s, this);
929 return true;
930 }
931 default:
932 return isSubtype(s, t);
933 }
934 }
935 // </editor-fold>
936
937 // <editor-fold defaultstate="collapsed" desc="isSameType">
938 /**
939 * Are corresponding elements of the lists the same type? If
940 * lists are of different length, return false.
941 */
942 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
943 return isSameTypes(ts, ss, false);
944 }
945 public boolean isSameTypes(List<Type> ts, List<Type> ss, boolean strict) {
946 while (ts.tail != null && ss.tail != null
947 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
948 isSameType(ts.head, ss.head, strict)) {
949 ts = ts.tail;
950 ss = ss.tail;
951 }
952 return ts.tail == null && ss.tail == null;
953 /*inlined: ts.isEmpty() && ss.isEmpty();*/
954 }
955
956 /**
957 * Is t the same type as s?
958 */
959 public boolean isSameType(Type t, Type s) {
960 return isSameType(t, s, false);
961 }
962 public boolean isSameType(Type t, Type s, boolean strict) {
963 return strict ?
964 isSameTypeStrict.visit(t, s) :
965 isSameTypeLoose.visit(t, s);
966 }
967 // where
968 abstract class SameTypeVisitor extends TypeRelation {
969
970 public Boolean visitType(Type t, Type s) {
971 if (t == s)
972 return true;
973
974 if (s.isPartial())
975 return visit(s, t);
976
977 switch (t.tag) {
978 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
979 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
980 return t.tag == s.tag;
981 case TYPEVAR: {
982 if (s.tag == TYPEVAR) {
983 //type-substitution does not preserve type-var types
984 //check that type var symbols and bounds are indeed the same
985 return sameTypeVars((TypeVar)t, (TypeVar)s);
986 }
987 else {
988 //special case for s == ? super X, where upper(s) = u
989 //check that u == t, where u has been set by Type.withTypeVar
990 return s.isSuperBound() &&
991 !s.isExtendsBound() &&
992 visit(t, upperBound(s));
993 }
994 }
995 default:
996 throw new AssertionError("isSameType " + t.tag);
997 }
998 }
999
1000 abstract boolean sameTypeVars(TypeVar tv1, TypeVar tv2);
1001
1002 @Override
1003 public Boolean visitWildcardType(WildcardType t, Type s) {
1004 if (s.isPartial())
1005 return visit(s, t);
1006 else
1007 return false;
1008 }
1009
1010 @Override
1011 public Boolean visitClassType(ClassType t, Type s) {
1012 if (t == s)
1013 return true;
1014
1015 if (s.isPartial())
1016 return visit(s, t);
1017
1018 if (s.isSuperBound() && !s.isExtendsBound())
1019 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
1020
1021 if (t.isCompound() && s.isCompound()) {
1022 if (!visit(supertype(t), supertype(s)))
1023 return false;
1024
1025 HashSet<UniqueType> set = new HashSet<UniqueType>();
1026 for (Type x : interfaces(t))
1027 set.add(new UniqueType(x, Types.this));
1028 for (Type x : interfaces(s)) {
1029 if (!set.remove(new UniqueType(x, Types.this)))
1030 return false;
1031 }
1032 return (set.isEmpty());
1033 }
1034 return t.tsym == s.tsym
1035 && visit(t.getEnclosingType(), s.getEnclosingType())
1036 && containsTypes(t.getTypeArguments(), s.getTypeArguments());
1037 }
1038
1039 abstract protected boolean containsTypes(List<Type> ts1, List<Type> ts2);
1040
1041 @Override
1042 public Boolean visitArrayType(ArrayType t, Type s) {
1043 if (t == s)
1044 return true;
1045
1046 if (s.isPartial())
1047 return visit(s, t);
1048
1049 return s.hasTag(ARRAY)
1050 && containsTypeEquivalent(t.elemtype, elemtype(s));
1051 }
1052
1053 @Override
1054 public Boolean visitMethodType(MethodType t, Type s) {
1055 // isSameType for methods does not take thrown
1056 // exceptions into account!
1057 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
1058 }
1059
1060 @Override
1061 public Boolean visitPackageType(PackageType t, Type s) {
1062 return t == s;
1063 }
1064
1065 @Override
1066 public Boolean visitForAll(ForAll t, Type s) {
1067 if (s.tag != FORALL)
1068 return false;
1069
1070 ForAll forAll = (ForAll)s;
1071 return hasSameBounds(t, forAll)
1072 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1073 }
1074
1075 @Override
1076 public Boolean visitUndetVar(UndetVar t, Type s) {
1077 if (s.tag == WILDCARD)
1078 // FIXME, this might be leftovers from before capture conversion
1079 return false;
1080
1081 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
1082 return true;
1083
1084 t.addBound(InferenceBound.EQ, s, Types.this);
1085
1086 return true;
1087 }
1088
1089 @Override
1090 public Boolean visitErrorType(ErrorType t, Type s) {
1091 return true;
1092 }
1093 }
1094
1095 /**
1096 * Standard type-equality relation - type variables are considered
1097 * equals if they share the same type symbol.
1098 */
1099 TypeRelation isSameTypeLoose = new SameTypeVisitor() {
1100 @Override
1101 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
1102 return tv1.tsym == tv2.tsym && visit(tv1.getUpperBound(), tv2.getUpperBound());
1103 }
1104 @Override
1105 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
1106 return containsTypeEquivalent(ts1, ts2);
1107 }
1108 };
1109
1110 /**
1111 * Strict type-equality relation - type variables are considered
1112 * equals if they share the same object identity.
1113 */
1114 TypeRelation isSameTypeStrict = new SameTypeVisitor() {
1115 @Override
1116 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
1117 return tv1 == tv2;
1118 }
1119 @Override
1120 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
1121 return isSameTypes(ts1, ts2, true);
1122 }
1123
1124 @Override
1125 public Boolean visitWildcardType(WildcardType t, Type s) {
1126 if (!s.hasTag(WILDCARD)) {
1127 return false;
1128 } else {
1129 WildcardType t2 = (WildcardType)s;
1130 return t.kind == t2.kind &&
1131 isSameType(t.type, t2.type, true);
1132 }
1133 }
1134 };
1135 // </editor-fold>
1136
1137 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1138 public boolean containedBy(Type t, Type s) {
1139 switch (t.tag) {
1140 case UNDETVAR:
1141 if (s.tag == WILDCARD) {
1142 UndetVar undetvar = (UndetVar)t;
1143 WildcardType wt = (WildcardType)s;
1144 switch(wt.kind) {
1145 case UNBOUND: //similar to ? extends Object
1146 case EXTENDS: {
1147 Type bound = upperBound(s);
1148 undetvar.addBound(InferenceBound.UPPER, bound, this);
1149 break;
1150 }
1151 case SUPER: {
1152 Type bound = lowerBound(s);
1153 undetvar.addBound(InferenceBound.LOWER, bound, this);
1154 break;
1155 }
1156 }
1157 return true;
1158 } else {
1159 return isSameType(t, s);
1160 }
1161 case ERROR:
1162 return true;
1163 default:
1164 return containsType(s, t);
1165 }
1166 }
1167
1168 boolean containsType(List<Type> ts, List<Type> ss) {
1169 while (ts.nonEmpty() && ss.nonEmpty()
1170 && containsType(ts.head, ss.head)) {
1171 ts = ts.tail;
1172 ss = ss.tail;
1173 }
1174 return ts.isEmpty() && ss.isEmpty();
1175 }
1176
1177 /**
1178 * Check if t contains s.
1179 *
1180 * <p>T contains S if:
1181 *
1182 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1183 *
1184 * <p>This relation is only used by ClassType.isSubtype(), that
1185 * is,
1186 *
1187 * <p>{@code C<S> <: C<T> if T contains S.}
1188 *
1189 * <p>Because of F-bounds, this relation can lead to infinite
1190 * recursion. Thus we must somehow break that recursion. Notice
1191 * that containsType() is only called from ClassType.isSubtype().
1192 * Since the arguments have already been checked against their
1193 * bounds, we know:
1194 *
1195 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1196 *
1197 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1198 *
1199 * @param t a type
1200 * @param s a type
1201 */
1202 public boolean containsType(Type t, Type s) {
1203 return containsType.visit(t, s);
1204 }
1205 // where
1206 private TypeRelation containsType = new TypeRelation() {
1207
1208 private Type U(Type t) {
1209 while (t.tag == WILDCARD) {
1210 WildcardType w = (WildcardType)t;
1211 if (w.isSuperBound())
1212 return w.bound == null ? syms.objectType : w.bound.bound;
1213 else
1214 t = w.type;
1215 }
1216 return t;
1217 }
1218
1219 private Type L(Type t) {
1220 while (t.tag == WILDCARD) {
1221 WildcardType w = (WildcardType)t;
1222 if (w.isExtendsBound())
1223 return syms.botType;
1224 else
1225 t = w.type;
1226 }
1227 return t;
1228 }
1229
1230 public Boolean visitType(Type t, Type s) {
1231 if (s.isPartial())
1232 return containedBy(s, t);
1233 else
1234 return isSameType(t, s);
1235 }
1236
1237 // void debugContainsType(WildcardType t, Type s) {
1238 // System.err.println();
1239 // System.err.format(" does %s contain %s?%n", t, s);
1240 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1241 // upperBound(s), s, t, U(t),
1242 // t.isSuperBound()
1243 // || isSubtypeNoCapture(upperBound(s), U(t)));
1244 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1245 // L(t), t, s, lowerBound(s),
1246 // t.isExtendsBound()
1247 // || isSubtypeNoCapture(L(t), lowerBound(s)));
1248 // System.err.println();
1249 // }
1250
1251 @Override
1252 public Boolean visitWildcardType(WildcardType t, Type s) {
1253 if (s.isPartial())
1254 return containedBy(s, t);
1255 else {
1256 // debugContainsType(t, s);
1257 return isSameWildcard(t, s)
1258 || isCaptureOf(s, t)
1259 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
1260 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
1261 }
1262 }
1263
1264 @Override
1265 public Boolean visitUndetVar(UndetVar t, Type s) {
1266 if (s.tag != WILDCARD)
1267 return isSameType(t, s);
1268 else
1269 return false;
1270 }
1271
1272 @Override
1273 public Boolean visitErrorType(ErrorType t, Type s) {
1274 return true;
1275 }
1276 };
1277
1278 public boolean isCaptureOf(Type s, WildcardType t) {
1279 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
1280 return false;
1281 return isSameWildcard(t, ((CapturedType)s).wildcard);
1282 }
1283
1284 public boolean isSameWildcard(WildcardType t, Type s) {
1285 if (s.tag != WILDCARD)
1286 return false;
1287 WildcardType w = (WildcardType)s;
1288 return w.kind == t.kind && w.type == t.type;
1289 }
1290
1291 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1292 while (ts.nonEmpty() && ss.nonEmpty()
1293 && containsTypeEquivalent(ts.head, ss.head)) {
1294 ts = ts.tail;
1295 ss = ss.tail;
1296 }
1297 return ts.isEmpty() && ss.isEmpty();
1298 }
1299 // </editor-fold>
1300
1301 /**
1302 * Can t and s be compared for equality?
1303 *
1304 */
1305 public boolean isEqualityComparable(Type t, Type s, Warner warn) {
1306 if (t.tag == ERROR)
1307 return true;
1308 boolean tPrimitive = t.isPrimitive();
1309 boolean sPrimitive = s.isPrimitive();
1310 if (tPrimitive && sPrimitive) {
1311 return isSubtypeUnchecked(t, s, warn);
1312 } else if (!tPrimitive && !sPrimitive)
1313 return isCastable(t, s, warn);
1314 else if (allowBoxing) {
1315 return tPrimitive
1316 ? isSubtype(unboxedType(s), t)
1317 : isSubtype(unboxedType(t), s);
1318 } else
1319 return false;
1320 }
1321
1322 // <editor-fold defaultstate="collapsed" desc="isCastable">
1323 public boolean isCastable(Type t, Type s) {
1324 return isCastable(t, s, noWarnings);
1325 }
1326
1327 /**
1328 * Is t is castable to s?<br>
1329 * s is assumed to be an erased type.<br>
1330 * (not defined for Method and ForAll types).
1331 */
1332 public boolean isCastable(Type t, Type s, Warner warn) {
1333 if (t == s)
1334 return true;
1335
1336 if (t.isPrimitive() != s.isPrimitive())
1337 return allowBoxing && (
1338 isConvertible(t, s, warn)
1339 || (allowObjectToPrimitiveCast &&
1340 s.isPrimitive() &&
1341 isSubtype(boxedClass(s).type, t)));
1342 if (warn != warnStack.head) {
1343 try {
1344 warnStack = warnStack.prepend(warn);
1345 checkUnsafeVarargsConversion(t, s, warn);
1346 return isCastable.visit(t,s);
1347 } finally {
1348 warnStack = warnStack.tail;
1349 }
1350 } else {
1351 return isCastable.visit(t,s);
1352 }
1353 }
1354 // where
1355 private TypeRelation isCastable = new TypeRelation() {
1356
1357 public Boolean visitType(Type t, Type s) {
1358 if (s.tag == ERROR)
1359 return true;
1360
1361 switch (t.tag) {
1362 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1363 case DOUBLE:
1364 return s.isNumeric();
1365 case BOOLEAN:
1366 return s.tag == BOOLEAN;
1367 case VOID:
1368 return false;
1369 case BOT:
1370 return isSubtype(t, s);
1371 default:
1372 throw new AssertionError();
1373 }
1374 }
1375
1376 @Override
1377 public Boolean visitWildcardType(WildcardType t, Type s) {
1378 return isCastable(upperBound(t), s, warnStack.head);
1379 }
1380
1381 @Override
1382 public Boolean visitClassType(ClassType t, Type s) {
1383 if (s.tag == ERROR || s.tag == BOT)
1384 return true;
1385
1386 if (s.tag == TYPEVAR) {
1387 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1388 warnStack.head.warn(LintCategory.UNCHECKED);
1389 return true;
1390 } else {
1391 return false;
1392 }
1393 }
1394
1395 if (t.isCompound() || s.isCompound()) {
1396 return !t.isCompound() ?
1397 visitIntersectionType((IntersectionClassType)s, t, true) :
1398 visitIntersectionType((IntersectionClassType)t, s, false);
1399 }
1400
1401 if (s.tag == CLASS || s.tag == ARRAY) {
1402 boolean upcast;
1403 if ((upcast = isSubtype(erasure(t), erasure(s)))
1404 || isSubtype(erasure(s), erasure(t))) {
1405 if (!upcast && s.tag == ARRAY) {
1406 if (!isReifiable(s))
1407 warnStack.head.warn(LintCategory.UNCHECKED);
1408 return true;
1409 } else if (s.isRaw()) {
1410 return true;
1411 } else if (t.isRaw()) {
1412 if (!isUnbounded(s))
1413 warnStack.head.warn(LintCategory.UNCHECKED);
1414 return true;
1415 }
1416 // Assume |a| <: |b|
1417 final Type a = upcast ? t : s;
1418 final Type b = upcast ? s : t;
1419 final boolean HIGH = true;
1420 final boolean LOW = false;
1421 final boolean DONT_REWRITE_TYPEVARS = false;
1422 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1423 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1424 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1425 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1426 Type lowSub = asSub(bLow, aLow.tsym);
1427 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1428 if (highSub == null) {
1429 final boolean REWRITE_TYPEVARS = true;
1430 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1431 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1432 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1433 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1434 lowSub = asSub(bLow, aLow.tsym);
1435 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1436 }
1437 if (highSub != null) {
1438 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1439 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1440 }
1441 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1442 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1443 && !disjointTypes(aLow.allparams(), highSub.allparams())
1444 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1445 if (upcast ? giveWarning(a, b) :
1446 giveWarning(b, a))
1447 warnStack.head.warn(LintCategory.UNCHECKED);
1448 return true;
1449 }
1450 }
1451 if (isReifiable(s))
1452 return isSubtypeUnchecked(a, b);
1453 else
1454 return isSubtypeUnchecked(a, b, warnStack.head);
1455 }
1456
1457 // Sidecast
1458 if (s.tag == CLASS) {
1459 if ((s.tsym.flags() & INTERFACE) != 0) {
1460 return ((t.tsym.flags() & FINAL) == 0)
1461 ? sideCast(t, s, warnStack.head)
1462 : sideCastFinal(t, s, warnStack.head);
1463 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1464 return ((s.tsym.flags() & FINAL) == 0)
1465 ? sideCast(t, s, warnStack.head)
1466 : sideCastFinal(t, s, warnStack.head);
1467 } else {
1468 // unrelated class types
1469 return false;
1470 }
1471 }
1472 }
1473 return false;
1474 }
1475
1476 boolean visitIntersectionType(IntersectionClassType ict, Type s, boolean reverse) {
1477 Warner warn = noWarnings;
1478 for (Type c : ict.getComponents()) {
1479 warn.clear();
1480 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
1481 return false;
1482 }
1483 if (warn.hasLint(LintCategory.UNCHECKED))
1484 warnStack.head.warn(LintCategory.UNCHECKED);
1485 return true;
1486 }
1487
1488 @Override
1489 public Boolean visitArrayType(ArrayType t, Type s) {
1490 switch (s.tag) {
1491 case ERROR:
1492 case BOT:
1493 return true;
1494 case TYPEVAR:
1495 if (isCastable(s, t, noWarnings)) {
1496 warnStack.head.warn(LintCategory.UNCHECKED);
1497 return true;
1498 } else {
1499 return false;
1500 }
1501 case CLASS:
1502 return isSubtype(t, s);
1503 case ARRAY:
1504 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1505 return elemtype(t).tag == elemtype(s).tag;
1506 } else {
1507 return visit(elemtype(t), elemtype(s));
1508 }
1509 default:
1510 return false;
1511 }
1512 }
1513
1514 @Override
1515 public Boolean visitTypeVar(TypeVar t, Type s) {
1516 switch (s.tag) {
1517 case ERROR:
1518 case BOT:
1519 return true;
1520 case TYPEVAR:
1521 if (isSubtype(t, s)) {
1522 return true;
1523 } else if (isCastable(t.bound, s, noWarnings)) {
1524 warnStack.head.warn(LintCategory.UNCHECKED);
1525 return true;
1526 } else {
1527 return false;
1528 }
1529 default:
1530 return isCastable(t.bound, s, warnStack.head);
1531 }
1532 }
1533
1534 @Override
1535 public Boolean visitErrorType(ErrorType t, Type s) {
1536 return true;
1537 }
1538 };
1539 // </editor-fold>
1540
1541 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1542 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1543 while (ts.tail != null && ss.tail != null) {
1544 if (disjointType(ts.head, ss.head)) return true;
1545 ts = ts.tail;
1546 ss = ss.tail;
1547 }
1548 return false;
1549 }
1550
1551 /**
1552 * Two types or wildcards are considered disjoint if it can be
1553 * proven that no type can be contained in both. It is
1554 * conservative in that it is allowed to say that two types are
1555 * not disjoint, even though they actually are.
1556 *
1557 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1558 * {@code X} and {@code Y} are not disjoint.
1559 */
1560 public boolean disjointType(Type t, Type s) {
1561 return disjointType.visit(t, s);
1562 }
1563 // where
1564 private TypeRelation disjointType = new TypeRelation() {
1565
1566 private Set<TypePair> cache = new HashSet<TypePair>();
1567
1568 public Boolean visitType(Type t, Type s) {
1569 if (s.tag == WILDCARD)
1570 return visit(s, t);
1571 else
1572 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1573 }
1574
1575 private boolean isCastableRecursive(Type t, Type s) {
1576 TypePair pair = new TypePair(t, s);
1577 if (cache.add(pair)) {
1578 try {
1579 return Types.this.isCastable(t, s);
1580 } finally {
1581 cache.remove(pair);
1582 }
1583 } else {
1584 return true;
1585 }
1586 }
1587
1588 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1589 TypePair pair = new TypePair(t, s);
1590 if (cache.add(pair)) {
1591 try {
1592 return Types.this.notSoftSubtype(t, s);
1593 } finally {
1594 cache.remove(pair);
1595 }
1596 } else {
1597 return false;
1598 }
1599 }
1600
1601 @Override
1602 public Boolean visitWildcardType(WildcardType t, Type s) {
1603 if (t.isUnbound())
1604 return false;
1605
1606 if (s.tag != WILDCARD) {
1607 if (t.isExtendsBound())
1608 return notSoftSubtypeRecursive(s, t.type);
1609 else // isSuperBound()
1610 return notSoftSubtypeRecursive(t.type, s);
1611 }
1612
1613 if (s.isUnbound())
1614 return false;
1615
1616 if (t.isExtendsBound()) {
1617 if (s.isExtendsBound())
1618 return !isCastableRecursive(t.type, upperBound(s));
1619 else if (s.isSuperBound())
1620 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1621 } else if (t.isSuperBound()) {
1622 if (s.isExtendsBound())
1623 return notSoftSubtypeRecursive(t.type, upperBound(s));
1624 }
1625 return false;
1626 }
1627 };
1628 // </editor-fold>
1629
1630 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1631 /**
1632 * Returns the lower bounds of the formals of a method.
1633 */
1634 public List<Type> lowerBoundArgtypes(Type t) {
1635 return lowerBounds(t.getParameterTypes());
1636 }
1637 public List<Type> lowerBounds(List<Type> ts) {
1638 return map(ts, lowerBoundMapping);
1639 }
1640 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1641 public Type apply(Type t) {
1642 return lowerBound(t);
1643 }
1644 };
1645 // </editor-fold>
1646
1647 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1648 /**
1649 * This relation answers the question: is impossible that
1650 * something of type `t' can be a subtype of `s'? This is
1651 * different from the question "is `t' not a subtype of `s'?"
1652 * when type variables are involved: Integer is not a subtype of T
1653 * where {@code <T extends Number>} but it is not true that Integer cannot
1654 * possibly be a subtype of T.
1655 */
1656 public boolean notSoftSubtype(Type t, Type s) {
1657 if (t == s) return false;
1658 if (t.tag == TYPEVAR) {
1659 TypeVar tv = (TypeVar) t;
1660 return !isCastable(tv.bound,
1661 relaxBound(s),
1662 noWarnings);
1663 }
1664 if (s.tag != WILDCARD)
1665 s = upperBound(s);
1666
1667 return !isSubtype(t, relaxBound(s));
1668 }
1669
1670 private Type relaxBound(Type t) {
1671 if (t.tag == TYPEVAR) {
1672 while (t.tag == TYPEVAR)
1673 t = t.getUpperBound();
1674 t = rewriteQuantifiers(t, true, true);
1675 }
1676 return t;
1677 }
1678 // </editor-fold>
1679
1680 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1681 public boolean isReifiable(Type t) {
1682 return isReifiable.visit(t);
1683 }
1684 // where
1685 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1686
1687 public Boolean visitType(Type t, Void ignored) {
1688 return true;
1689 }
1690
1691 @Override
1692 public Boolean visitClassType(ClassType t, Void ignored) {
1693 if (t.isCompound())
1694 return false;
1695 else {
1696 if (!t.isParameterized())
1697 return true;
1698
1699 for (Type param : t.allparams()) {
1700 if (!param.isUnbound())
1701 return false;
1702 }
1703 return true;
1704 }
1705 }
1706
1707 @Override
1708 public Boolean visitArrayType(ArrayType t, Void ignored) {
1709 return visit(t.elemtype);
1710 }
1711
1712 @Override
1713 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1714 return false;
1715 }
1716 };
1717 // </editor-fold>
1718
1719 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1720 public boolean isArray(Type t) {
1721 while (t.tag == WILDCARD)
1722 t = upperBound(t);
1723 return t.tag == ARRAY;
1724 }
1725
1726 /**
1727 * The element type of an array.
1728 */
1729 public Type elemtype(Type t) {
1730 switch (t.tag) {
1731 case WILDCARD:
1732 return elemtype(upperBound(t));
1733 case ARRAY:
1734 t = t.unannotatedType();
1735 return ((ArrayType)t).elemtype;
1736 case FORALL:
1737 return elemtype(((ForAll)t).qtype);
1738 case ERROR:
1739 return t;
1740 default:
1741 return null;
1742 }
1743 }
1744
1745 public Type elemtypeOrType(Type t) {
1746 Type elemtype = elemtype(t);
1747 return elemtype != null ?
1748 elemtype :
1749 t;
1750 }
1751
1752 /**
1753 * Mapping to take element type of an arraytype
1754 */
1755 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1756 public Type apply(Type t) { return elemtype(t); }
1757 };
1758
1759 /**
1760 * The number of dimensions of an array type.
1761 */
1762 public int dimensions(Type t) {
1763 int result = 0;
1764 while (t.tag == ARRAY) {
1765 result++;
1766 t = elemtype(t);
1767 }
1768 return result;
1769 }
1770
1771 /**
1772 * Returns an ArrayType with the component type t
1773 *
1774 * @param t The component type of the ArrayType
1775 * @return the ArrayType for the given component
1776 */
1777 public ArrayType makeArrayType(Type t) {
1778 if (t.tag == VOID ||
1779 t.tag == PACKAGE) {
1780 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
1781 }
1782 return new ArrayType(t, syms.arrayClass);
1783 }
1784 // </editor-fold>
1785
1786 // <editor-fold defaultstate="collapsed" desc="asSuper">
1787 /**
1788 * Return the (most specific) base type of t that starts with the
1789 * given symbol. If none exists, return null.
1790 *
1791 * @param t a type
1792 * @param sym a symbol
1793 */
1794 public Type asSuper(Type t, Symbol sym) {
1795 return asSuper.visit(t, sym);
1796 }
1797 // where
1798 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1799
1800 public Type visitType(Type t, Symbol sym) {
1801 return null;
1802 }
1803
1804 @Override
1805 public Type visitClassType(ClassType t, Symbol sym) {
1806 if (t.tsym == sym)
1807 return t;
1808
1809 Type st = supertype(t);
1810 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1811 Type x = asSuper(st, sym);
1812 if (x != null)
1813 return x;
1814 }
1815 if ((sym.flags() & INTERFACE) != 0) {
1816 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1817 Type x = asSuper(l.head, sym);
1818 if (x != null)
1819 return x;
1820 }
1821 }
1822 return null;
1823 }
1824
1825 @Override
1826 public Type visitArrayType(ArrayType t, Symbol sym) {
1827 return isSubtype(t, sym.type) ? sym.type : null;
1828 }
1829
1830 @Override
1831 public Type visitTypeVar(TypeVar t, Symbol sym) {
1832 if (t.tsym == sym)
1833 return t;
1834 else
1835 return asSuper(t.bound, sym);
1836 }
1837
1838 @Override
1839 public Type visitErrorType(ErrorType t, Symbol sym) {
1840 return t;
1841 }
1842 };
1843
1844 /**
1845 * Return the base type of t or any of its outer types that starts
1846 * with the given symbol. If none exists, return null.
1847 *
1848 * @param t a type
1849 * @param sym a symbol
1850 */
1851 public Type asOuterSuper(Type t, Symbol sym) {
1852 switch (t.tag) {
1853 case CLASS:
1854 do {
1855 Type s = asSuper(t, sym);
1856 if (s != null) return s;
1857 t = t.getEnclosingType();
1858 } while (t.tag == CLASS);
1859 return null;
1860 case ARRAY:
1861 return isSubtype(t, sym.type) ? sym.type : null;
1862 case TYPEVAR:
1863 return asSuper(t, sym);
1864 case ERROR:
1865 return t;
1866 default:
1867 return null;
1868 }
1869 }
1870
1871 /**
1872 * Return the base type of t or any of its enclosing types that
1873 * starts with the given symbol. If none exists, return null.
1874 *
1875 * @param t a type
1876 * @param sym a symbol
1877 */
1878 public Type asEnclosingSuper(Type t, Symbol sym) {
1879 switch (t.tag) {
1880 case CLASS:
1881 do {
1882 Type s = asSuper(t, sym);
1883 if (s != null) return s;
1884 Type outer = t.getEnclosingType();
1885 t = (outer.tag == CLASS) ? outer :
1886 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1887 Type.noType;
1888 } while (t.tag == CLASS);
1889 return null;
1890 case ARRAY:
1891 return isSubtype(t, sym.type) ? sym.type : null;
1892 case TYPEVAR:
1893 return asSuper(t, sym);
1894 case ERROR:
1895 return t;
1896 default:
1897 return null;
1898 }
1899 }
1900 // </editor-fold>
1901
1902 // <editor-fold defaultstate="collapsed" desc="memberType">
1903 /**
1904 * The type of given symbol, seen as a member of t.
1905 *
1906 * @param t a type
1907 * @param sym a symbol
1908 */
1909 public Type memberType(Type t, Symbol sym) {
1910 return (sym.flags() & STATIC) != 0
1911 ? sym.type
1912 : memberType.visit(t, sym);
1913 }
1914 // where
1915 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1916
1917 public Type visitType(Type t, Symbol sym) {
1918 return sym.type;
1919 }
1920
1921 @Override
1922 public Type visitWildcardType(WildcardType t, Symbol sym) {
1923 return memberType(upperBound(t), sym);
1924 }
1925
1926 @Override
1927 public Type visitClassType(ClassType t, Symbol sym) {
1928 Symbol owner = sym.owner;
1929 long flags = sym.flags();
1930 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1931 Type base = asOuterSuper(t, owner);
1932 //if t is an intersection type T = CT & I1 & I2 ... & In
1933 //its supertypes CT, I1, ... In might contain wildcards
1934 //so we need to go through capture conversion
1935 base = t.isCompound() ? capture(base) : base;
1936 if (base != null) {
1937 List<Type> ownerParams = owner.type.allparams();
1938 List<Type> baseParams = base.allparams();
1939 if (ownerParams.nonEmpty()) {
1940 if (baseParams.isEmpty()) {
1941 // then base is a raw type
1942 return erasure(sym.type);
1943 } else {
1944 return subst(sym.type, ownerParams, baseParams);
1945 }
1946 }
1947 }
1948 }
1949 return sym.type;
1950 }
1951
1952 @Override
1953 public Type visitTypeVar(TypeVar t, Symbol sym) {
1954 return memberType(t.bound, sym);
1955 }
1956
1957 @Override
1958 public Type visitErrorType(ErrorType t, Symbol sym) {
1959 return t;
1960 }
1961 };
1962 // </editor-fold>
1963
1964 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1965 public boolean isAssignable(Type t, Type s) {
1966 return isAssignable(t, s, noWarnings);
1967 }
1968
1969 /**
1970 * Is t assignable to s?<br>
1971 * Equivalent to subtype except for constant values and raw
1972 * types.<br>
1973 * (not defined for Method and ForAll types)
1974 */
1975 public boolean isAssignable(Type t, Type s, Warner warn) {
1976 if (t.tag == ERROR)
1977 return true;
1978 if (t.tag.isSubRangeOf(INT) && t.constValue() != null) {
1979 int value = ((Number)t.constValue()).intValue();
1980 switch (s.tag) {
1981 case BYTE:
1982 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1983 return true;
1984 break;
1985 case CHAR:
1986 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1987 return true;
1988 break;
1989 case SHORT:
1990 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1991 return true;
1992 break;
1993 case INT:
1994 return true;
1995 case CLASS:
1996 switch (unboxedType(s).tag) {
1997 case BYTE:
1998 case CHAR:
1999 case SHORT:
2000 return isAssignable(t, unboxedType(s), warn);
2001 }
2002 break;
2003 }
2004 }
2005 return isConvertible(t, s, warn);
2006 }
2007 // </editor-fold>
2008
2009 // <editor-fold defaultstate="collapsed" desc="erasure">
2010 /**
2011 * The erasure of t {@code |t|} -- the type that results when all
2012 * type parameters in t are deleted.
2013 */
2014 public Type erasure(Type t) {
2015 return eraseNotNeeded(t)? t : erasure(t, false);
2016 }
2017 //where
2018 private boolean eraseNotNeeded(Type t) {
2019 // We don't want to erase primitive types and String type as that
2020 // operation is idempotent. Also, erasing these could result in loss
2021 // of information such as constant values attached to such types.
2022 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2023 }
2024
2025 private Type erasure(Type t, boolean recurse) {
2026 if (t.isPrimitive())
2027 return t; /* fast special case */
2028 else
2029 return erasure.visit(t, recurse);
2030 }
2031 // where
2032 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
2033 public Type visitType(Type t, Boolean recurse) {
2034 if (t.isPrimitive())
2035 return t; /*fast special case*/
2036 else
2037 return t.map(recurse ? erasureRecFun : erasureFun);
2038 }
2039
2040 @Override
2041 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2042 return erasure(upperBound(t), recurse);
2043 }
2044
2045 @Override
2046 public Type visitClassType(ClassType t, Boolean recurse) {
2047 Type erased = t.tsym.erasure(Types.this);
2048 if (recurse) {
2049 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
2050 }
2051 return erased;
2052 }
2053
2054 @Override
2055 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2056 return erasure(t.bound, recurse);
2057 }
2058
2059 @Override
2060 public Type visitErrorType(ErrorType t, Boolean recurse) {
2061 return t;
2062 }
2063
2064 @Override
2065 public Type visitAnnotatedType(AnnotatedType t, Boolean recurse) {
2066 Type erased = erasure(t.underlyingType, recurse);
2067 if (erased.isAnnotated()) {
2068 // This can only happen when the underlying type is a
2069 // type variable and the upper bound of it is annotated.
2070 // The annotation on the type variable overrides the one
2071 // on the bound.
2072 erased = ((AnnotatedType)erased).underlyingType;
2073 }
2074 return new AnnotatedType(t.typeAnnotations, erased);
2075 }
2076 };
2077
2078 private Mapping erasureFun = new Mapping ("erasure") {
2079 public Type apply(Type t) { return erasure(t); }
2080 };
2081
2082 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
2083 public Type apply(Type t) { return erasureRecursive(t); }
2084 };
2085
2086 public List<Type> erasure(List<Type> ts) {
2087 return Type.map(ts, erasureFun);
2088 }
2089
2090 public Type erasureRecursive(Type t) {
2091 return erasure(t, true);
2092 }
2093
2094 public List<Type> erasureRecursive(List<Type> ts) {
2095 return Type.map(ts, erasureRecFun);
2096 }
2097 // </editor-fold>
2098
2099 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
2100 /**
2101 * Make a compound type from non-empty list of types
2102 *
2103 * @param bounds the types from which the compound type is formed
2104 * @param supertype is objectType if all bounds are interfaces,
2105 * null otherwise.
2106 */
2107 public Type makeCompoundType(List<Type> bounds) {
2108 return makeCompoundType(bounds, bounds.head.tsym.isInterface());
2109 }
2110 public Type makeCompoundType(List<Type> bounds, boolean allInterfaces) {
2111 Assert.check(bounds.nonEmpty());
2112 Type firstExplicitBound = bounds.head;
2113 if (allInterfaces) {
2114 bounds = bounds.prepend(syms.objectType);
2115 }
2116 ClassSymbol bc =
2117 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2118 Type.moreInfo
2119 ? names.fromString(bounds.toString())
2120 : names.empty,
2121 null,
2122 syms.noSymbol);
2123 bc.type = new IntersectionClassType(bounds, bc, allInterfaces);
2124 bc.erasure_field = (bounds.head.tag == TYPEVAR) ?
2125 syms.objectType : // error condition, recover
2126 erasure(firstExplicitBound);
2127 bc.members_field = new Scope(bc);
2128 return bc.type;
2129 }
2130
2131 /**
2132 * A convenience wrapper for {@link #makeCompoundType(List)}; the
2133 * arguments are converted to a list and passed to the other
2134 * method. Note that this might cause a symbol completion.
2135 * Hence, this version of makeCompoundType may not be called
2136 * during a classfile read.
2137 */
2138 public Type makeCompoundType(Type bound1, Type bound2) {
2139 return makeCompoundType(List.of(bound1, bound2));
2140 }
2141 // </editor-fold>
2142
2143 // <editor-fold defaultstate="collapsed" desc="supertype">
2144 public Type supertype(Type t) {
2145 return supertype.visit(t);
2146 }
2147 // where
2148 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2149
2150 public Type visitType(Type t, Void ignored) {
2151 // A note on wildcards: there is no good way to
2152 // determine a supertype for a super bounded wildcard.
2153 return null;
2154 }
2155
2156 @Override
2157 public Type visitClassType(ClassType t, Void ignored) {
2158 if (t.supertype_field == null) {
2159 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2160 // An interface has no superclass; its supertype is Object.
2161 if (t.isInterface())
2162 supertype = ((ClassType)t.tsym.type).supertype_field;
2163 if (t.supertype_field == null) {
2164 List<Type> actuals = classBound(t).allparams();
2165 List<Type> formals = t.tsym.type.allparams();
2166 if (t.hasErasedSupertypes()) {
2167 t.supertype_field = erasureRecursive(supertype);
2168 } else if (formals.nonEmpty()) {
2169 t.supertype_field = subst(supertype, formals, actuals);
2170 }
2171 else {
2172 t.supertype_field = supertype;
2173 }
2174 }
2175 }
2176 return t.supertype_field;
2177 }
2178
2179 /**
2180 * The supertype is always a class type. If the type
2181 * variable's bounds start with a class type, this is also
2182 * the supertype. Otherwise, the supertype is
2183 * java.lang.Object.
2184 */
2185 @Override
2186 public Type visitTypeVar(TypeVar t, Void ignored) {
2187 if (t.bound.tag == TYPEVAR ||
2188 (!t.bound.isCompound() && !t.bound.isInterface())) {
2189 return t.bound;
2190 } else {
2191 return supertype(t.bound);
2192 }
2193 }
2194
2195 @Override
2196 public Type visitArrayType(ArrayType t, Void ignored) {
2197 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2198 return arraySuperType();
2199 else
2200 return new ArrayType(supertype(t.elemtype), t.tsym);
2201 }
2202
2203 @Override
2204 public Type visitErrorType(ErrorType t, Void ignored) {
2205 return t;
2206 }
2207 };
2208 // </editor-fold>
2209
2210 // <editor-fold defaultstate="collapsed" desc="interfaces">
2211 /**
2212 * Return the interfaces implemented by this class.
2213 */
2214 public List<Type> interfaces(Type t) {
2215 return interfaces.visit(t);
2216 }
2217 // where
2218 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2219
2220 public List<Type> visitType(Type t, Void ignored) {
2221 return List.nil();
2222 }
2223
2224 @Override
2225 public List<Type> visitClassType(ClassType t, Void ignored) {
2226 if (t.interfaces_field == null) {
2227 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2228 if (t.interfaces_field == null) {
2229 // If t.interfaces_field is null, then t must
2230 // be a parameterized type (not to be confused
2231 // with a generic type declaration).
2232 // Terminology:
2233 // Parameterized type: List<String>
2234 // Generic type declaration: class List<E> { ... }
2235 // So t corresponds to List<String> and
2236 // t.tsym.type corresponds to List<E>.
2237 // The reason t must be parameterized type is
2238 // that completion will happen as a side
2239 // effect of calling
2240 // ClassSymbol.getInterfaces. Since
2241 // t.interfaces_field is null after
2242 // completion, we can assume that t is not the
2243 // type of a class/interface declaration.
2244 Assert.check(t != t.tsym.type, t);
2245 List<Type> actuals = t.allparams();
2246 List<Type> formals = t.tsym.type.allparams();
2247 if (t.hasErasedSupertypes()) {
2248 t.interfaces_field = erasureRecursive(interfaces);
2249 } else if (formals.nonEmpty()) {
2250 t.interfaces_field =
2251 upperBounds(subst(interfaces, formals, actuals));
2252 }
2253 else {
2254 t.interfaces_field = interfaces;
2255 }
2256 }
2257 }
2258 return t.interfaces_field;
2259 }
2260
2261 @Override
2262 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2263 if (t.bound.isCompound())
2264 return interfaces(t.bound);
2265
2266 if (t.bound.isInterface())
2267 return List.of(t.bound);
2268
2269 return List.nil();
2270 }
2271 };
2272
2273 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2274 for (Type i2 : interfaces(origin.type)) {
2275 if (isym == i2.tsym) return true;
2276 }
2277 return false;
2278 }
2279 // </editor-fold>
2280
2281 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2282 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
2283
2284 public boolean isDerivedRaw(Type t) {
2285 Boolean result = isDerivedRawCache.get(t);
2286 if (result == null) {
2287 result = isDerivedRawInternal(t);
2288 isDerivedRawCache.put(t, result);
2289 }
2290 return result;
2291 }
2292
2293 public boolean isDerivedRawInternal(Type t) {
2294 if (t.isErroneous())
2295 return false;
2296 return
2297 t.isRaw() ||
2298 supertype(t) != null && isDerivedRaw(supertype(t)) ||
2299 isDerivedRaw(interfaces(t));
2300 }
2301
2302 public boolean isDerivedRaw(List<Type> ts) {
2303 List<Type> l = ts;
2304 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2305 return l.nonEmpty();
2306 }
2307 // </editor-fold>
2308
2309 // <editor-fold defaultstate="collapsed" desc="setBounds">
2310 /**
2311 * Set the bounds field of the given type variable to reflect a
2312 * (possibly multiple) list of bounds.
2313 * @param t a type variable
2314 * @param bounds the bounds, must be nonempty
2315 * @param supertype is objectType if all bounds are interfaces,
2316 * null otherwise.
2317 */
2318 public void setBounds(TypeVar t, List<Type> bounds) {
2319 setBounds(t, bounds, bounds.head.tsym.isInterface());
2320 }
2321
2322 /**
2323 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
2324 * third parameter is computed directly, as follows: if all
2325 * all bounds are interface types, the computed supertype is Object,
2326 * otherwise the supertype is simply left null (in this case, the supertype
2327 * is assumed to be the head of the bound list passed as second argument).
2328 * Note that this check might cause a symbol completion. Hence, this version of
2329 * setBounds may not be called during a classfile read.
2330 */
2331 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2332 t.bound = bounds.tail.isEmpty() ?
2333 bounds.head :
2334 makeCompoundType(bounds, allInterfaces);
2335 t.rank_field = -1;
2336 }
2337 // </editor-fold>
2338
2339 // <editor-fold defaultstate="collapsed" desc="getBounds">
2340 /**
2341 * Return list of bounds of the given type variable.
2342 */
2343 public List<Type> getBounds(TypeVar t) {
2344 if (t.bound.hasTag(NONE))
2345 return List.nil();
2346 else if (t.bound.isErroneous() || !t.bound.isCompound())
2347 return List.of(t.bound);
2348 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2349 return interfaces(t).prepend(supertype(t));
2350 else
2351 // No superclass was given in bounds.
2352 // In this case, supertype is Object, erasure is first interface.
2353 return interfaces(t);
2354 }
2355 // </editor-fold>
2356
2357 // <editor-fold defaultstate="collapsed" desc="classBound">
2358 /**
2359 * If the given type is a (possibly selected) type variable,
2360 * return the bounding class of this type, otherwise return the
2361 * type itself.
2362 */
2363 public Type classBound(Type t) {
2364 return classBound.visit(t);
2365 }
2366 // where
2367 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2368
2369 public Type visitType(Type t, Void ignored) {
2370 return t;
2371 }
2372
2373 @Override
2374 public Type visitClassType(ClassType t, Void ignored) {
2375 Type outer1 = classBound(t.getEnclosingType());
2376 if (outer1 != t.getEnclosingType())
2377 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
2378 else
2379 return t;
2380 }
2381
2382 @Override
2383 public Type visitTypeVar(TypeVar t, Void ignored) {
2384 return classBound(supertype(t));
2385 }
2386
2387 @Override
2388 public Type visitErrorType(ErrorType t, Void ignored) {
2389 return t;
2390 }
2391 };
2392 // </editor-fold>
2393
2394 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
2395 /**
2396 * Returns true iff the first signature is a <em>sub
2397 * signature</em> of the other. This is <b>not</b> an equivalence
2398 * relation.
2399 *
2400 * @jls section 8.4.2.
2401 * @see #overrideEquivalent(Type t, Type s)
2402 * @param t first signature (possibly raw).
2403 * @param s second signature (could be subjected to erasure).
2404 * @return true if t is a sub signature of s.
2405 */
2406 public boolean isSubSignature(Type t, Type s) {
2407 return isSubSignature(t, s, true);
2408 }
2409
2410 public boolean isSubSignature(Type t, Type s, boolean strict) {
2411 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2412 }
2413
2414 /**
2415 * Returns true iff these signatures are related by <em>override
2416 * equivalence</em>. This is the natural extension of
2417 * isSubSignature to an equivalence relation.
2418 *
2419 * @jls section 8.4.2.
2420 * @see #isSubSignature(Type t, Type s)
2421 * @param t a signature (possible raw, could be subjected to
2422 * erasure).
2423 * @param s a signature (possible raw, could be subjected to
2424 * erasure).
2425 * @return true if either argument is a sub signature of the other.
2426 */
2427 public boolean overrideEquivalent(Type t, Type s) {
2428 return hasSameArgs(t, s) ||
2429 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2430 }
2431
2432 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2433 for (Scope.Entry e = syms.objectType.tsym.members().lookup(msym.name) ; e.scope != null ; e = e.next()) {
2434 if (msym.overrides(e.sym, origin, Types.this, true)) {
2435 return true;
2436 }
2437 }
2438 return false;
2439 }
2440
2441 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2442 class ImplementationCache {
2443
2444 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
2445 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
2446
2447 class Entry {
2448 final MethodSymbol cachedImpl;
2449 final Filter<Symbol> implFilter;
2450 final boolean checkResult;
2451 final int prevMark;
2452
2453 public Entry(MethodSymbol cachedImpl,
2454 Filter<Symbol> scopeFilter,
2455 boolean checkResult,
2456 int prevMark) {
2457 this.cachedImpl = cachedImpl;
2458 this.implFilter = scopeFilter;
2459 this.checkResult = checkResult;
2460 this.prevMark = prevMark;
2461 }
2462
2463 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
2464 return this.implFilter == scopeFilter &&
2465 this.checkResult == checkResult &&
2466 this.prevMark == mark;
2467 }
2468 }
2469
2470 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2471 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2472 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2473 if (cache == null) {
2474 cache = new HashMap<TypeSymbol, Entry>();
2475 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2476 }
2477 Entry e = cache.get(origin);
2478 CompoundScope members = membersClosure(origin.type, true);
2479 if (e == null ||
2480 !e.matches(implFilter, checkResult, members.getMark())) {
2481 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2482 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2483 return impl;
2484 }
2485 else {
2486 return e.cachedImpl;
2487 }
2488 }
2489
2490 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2491 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = supertype(t)) {
2492 while (t.tag == TYPEVAR)
2493 t = t.getUpperBound();
2494 TypeSymbol c = t.tsym;
2495 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2496 e.scope != null;
2497 e = e.next(implFilter)) {
2498 if (e.sym != null &&
2499 e.sym.overrides(ms, origin, Types.this, checkResult))
2500 return (MethodSymbol)e.sym;
2501 }
2502 }
2503 return null;
2504 }
2505 }
2506
2507 private ImplementationCache implCache = new ImplementationCache();
2508
2509 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2510 return implCache.get(ms, origin, checkResult, implFilter);
2511 }
2512 // </editor-fold>
2513
2514 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2515 class MembersClosureCache extends SimpleVisitor<CompoundScope, Boolean> {
2516
2517 private WeakHashMap<TypeSymbol, Entry> _map =
2518 new WeakHashMap<TypeSymbol, Entry>();
2519
2520 class Entry {
2521 final boolean skipInterfaces;
2522 final CompoundScope compoundScope;
2523
2524 public Entry(boolean skipInterfaces, CompoundScope compoundScope) {
2525 this.skipInterfaces = skipInterfaces;
2526 this.compoundScope = compoundScope;
2527 }
2528
2529 boolean matches(boolean skipInterfaces) {
2530 return this.skipInterfaces == skipInterfaces;
2531 }
2532 }
2533
2534 List<TypeSymbol> seenTypes = List.nil();
2535
2536 /** members closure visitor methods **/
2537
2538 public CompoundScope visitType(Type t, Boolean skipInterface) {
2539 return null;
2540 }
2541
2542 @Override
2543 public CompoundScope visitClassType(ClassType t, Boolean skipInterface) {
2544 if (seenTypes.contains(t.tsym)) {
2545 //this is possible when an interface is implemented in multiple
2546 //superclasses, or when a classs hierarchy is circular - in such
2547 //cases we don't need to recurse (empty scope is returned)
2548 return new CompoundScope(t.tsym);
2549 }
2550 try {
2551 seenTypes = seenTypes.prepend(t.tsym);
2552 ClassSymbol csym = (ClassSymbol)t.tsym;
2553 Entry e = _map.get(csym);
2554 if (e == null || !e.matches(skipInterface)) {
2555 CompoundScope membersClosure = new CompoundScope(csym);
2556 if (!skipInterface) {
2557 for (Type i : interfaces(t)) {
2558 membersClosure.addSubScope(visit(i, skipInterface));
2559 }
2560 }
2561 membersClosure.addSubScope(visit(supertype(t), skipInterface));
2562 membersClosure.addSubScope(csym.members());
2563 e = new Entry(skipInterface, membersClosure);
2564 _map.put(csym, e);
2565 }
2566 return e.compoundScope;
2567 }
2568 finally {
2569 seenTypes = seenTypes.tail;
2570 }
2571 }
2572
2573 @Override
2574 public CompoundScope visitTypeVar(TypeVar t, Boolean skipInterface) {
2575 return visit(t.getUpperBound(), skipInterface);
2576 }
2577 }
2578
2579 private MembersClosureCache membersCache = new MembersClosureCache();
2580
2581 public CompoundScope membersClosure(Type site, boolean skipInterface) {
2582 return membersCache.visit(site, skipInterface);
2583 }
2584 // </editor-fold>
2585
2586
2587 //where
2588 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
2589 Filter<Symbol> filter = new MethodFilter(ms, site);
2590 List<MethodSymbol> candidates = List.nil();
2591 for (Symbol s : membersClosure(site, false).getElements(filter)) {
2592 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
2593 return List.of((MethodSymbol)s);
2594 } else if (!candidates.contains(s)) {
2595 candidates = candidates.prepend((MethodSymbol)s);
2596 }
2597 }
2598 return prune(candidates);
2599 }
2600
2601 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
2602 ListBuffer<MethodSymbol> methodsMin = ListBuffer.lb();
2603 for (MethodSymbol m1 : methods) {
2604 boolean isMin_m1 = true;
2605 for (MethodSymbol m2 : methods) {
2606 if (m1 == m2) continue;
2607 if (m2.owner != m1.owner &&
2608 asSuper(m2.owner.type, m1.owner) != null) {
2609 isMin_m1 = false;
2610 break;
2611 }
2612 }
2613 if (isMin_m1)
2614 methodsMin.append(m1);
2615 }
2616 return methodsMin.toList();
2617 }
2618 // where
2619 private class MethodFilter implements Filter<Symbol> {
2620
2621 Symbol msym;
2622 Type site;
2623
2624 MethodFilter(Symbol msym, Type site) {
2625 this.msym = msym;
2626 this.site = site;
2627 }
2628
2629 public boolean accepts(Symbol s) {
2630 return s.kind == Kinds.MTH &&
2631 s.name == msym.name &&
2632 s.isInheritedIn(site.tsym, Types.this) &&
2633 overrideEquivalent(memberType(site, s), memberType(site, msym));
2634 }
2635 };
2636 // </editor-fold>
2637
2638 /**
2639 * Does t have the same arguments as s? It is assumed that both
2640 * types are (possibly polymorphic) method types. Monomorphic
2641 * method types "have the same arguments", if their argument lists
2642 * are equal. Polymorphic method types "have the same arguments",
2643 * if they have the same arguments after renaming all type
2644 * variables of one to corresponding type variables in the other,
2645 * where correspondence is by position in the type parameter list.
2646 */
2647 public boolean hasSameArgs(Type t, Type s) {
2648 return hasSameArgs(t, s, true);
2649 }
2650
2651 public boolean hasSameArgs(Type t, Type s, boolean strict) {
2652 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
2653 }
2654
2655 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
2656 return hasSameArgs.visit(t, s);
2657 }
2658 // where
2659 private class HasSameArgs extends TypeRelation {
2660
2661 boolean strict;
2662
2663 public HasSameArgs(boolean strict) {
2664 this.strict = strict;
2665 }
2666
2667 public Boolean visitType(Type t, Type s) {
2668 throw new AssertionError();
2669 }
2670
2671 @Override
2672 public Boolean visitMethodType(MethodType t, Type s) {
2673 return s.tag == METHOD
2674 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2675 }
2676
2677 @Override
2678 public Boolean visitForAll(ForAll t, Type s) {
2679 if (s.tag != FORALL)
2680 return strict ? false : visitMethodType(t.asMethodType(), s);
2681
2682 ForAll forAll = (ForAll)s;
2683 return hasSameBounds(t, forAll)
2684 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2685 }
2686
2687 @Override
2688 public Boolean visitErrorType(ErrorType t, Type s) {
2689 return false;
2690 }
2691 };
2692
2693 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
2694 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
2695
2696 // </editor-fold>
2697
2698 // <editor-fold defaultstate="collapsed" desc="subst">
2699 public List<Type> subst(List<Type> ts,
2700 List<Type> from,
2701 List<Type> to) {
2702 return new Subst(from, to).subst(ts);
2703 }
2704
2705 /**
2706 * Substitute all occurrences of a type in `from' with the
2707 * corresponding type in `to' in 't'. Match lists `from' and `to'
2708 * from the right: If lists have different length, discard leading
2709 * elements of the longer list.
2710 */
2711 public Type subst(Type t, List<Type> from, List<Type> to) {
2712 return new Subst(from, to).subst(t);
2713 }
2714
2715 private class Subst extends UnaryVisitor<Type> {
2716 List<Type> from;
2717 List<Type> to;
2718
2719 public Subst(List<Type> from, List<Type> to) {
2720 int fromLength = from.length();
2721 int toLength = to.length();
2722 while (fromLength > toLength) {
2723 fromLength--;
2724 from = from.tail;
2725 }
2726 while (fromLength < toLength) {
2727 toLength--;
2728 to = to.tail;
2729 }
2730 this.from = from;
2731 this.to = to;
2732 }
2733
2734 Type subst(Type t) {
2735 if (from.tail == null)
2736 return t;
2737 else
2738 return visit(t);
2739 }
2740
2741 List<Type> subst(List<Type> ts) {
2742 if (from.tail == null)
2743 return ts;
2744 boolean wild = false;
2745 if (ts.nonEmpty() && from.nonEmpty()) {
2746 Type head1 = subst(ts.head);
2747 List<Type> tail1 = subst(ts.tail);
2748 if (head1 != ts.head || tail1 != ts.tail)
2749 return tail1.prepend(head1);
2750 }
2751 return ts;
2752 }
2753
2754 public Type visitType(Type t, Void ignored) {
2755 return t;
2756 }
2757
2758 @Override
2759 public Type visitMethodType(MethodType t, Void ignored) {
2760 List<Type> argtypes = subst(t.argtypes);
2761 Type restype = subst(t.restype);
2762 List<Type> thrown = subst(t.thrown);
2763 if (argtypes == t.argtypes &&
2764 restype == t.restype &&
2765 thrown == t.thrown)
2766 return t;
2767 else
2768 return new MethodType(argtypes, restype, thrown, t.tsym);
2769 }
2770
2771 @Override
2772 public Type visitTypeVar(TypeVar t, Void ignored) {
2773 for (List<Type> from = this.from, to = this.to;
2774 from.nonEmpty();
2775 from = from.tail, to = to.tail) {
2776 if (t == from.head) {
2777 return to.head.withTypeVar(t);
2778 }
2779 }
2780 return t;
2781 }
2782
2783 @Override
2784 public Type visitClassType(ClassType t, Void ignored) {
2785 if (!t.isCompound()) {
2786 List<Type> typarams = t.getTypeArguments();
2787 List<Type> typarams1 = subst(typarams);
2788 Type outer = t.getEnclosingType();
2789 Type outer1 = subst(outer);
2790 if (typarams1 == typarams && outer1 == outer)
2791 return t;
2792 else
2793 return new ClassType(outer1, typarams1, t.tsym);
2794 } else {
2795 Type st = subst(supertype(t));
2796 List<Type> is = upperBounds(subst(interfaces(t)));
2797 if (st == supertype(t) && is == interfaces(t))
2798 return t;
2799 else
2800 return makeCompoundType(is.prepend(st));
2801 }
2802 }
2803
2804 @Override
2805 public Type visitWildcardType(WildcardType t, Void ignored) {
2806 Type bound = t.type;
2807 if (t.kind != BoundKind.UNBOUND)
2808 bound = subst(bound);
2809 if (bound == t.type) {
2810 return t;
2811 } else {
2812 if (t.isExtendsBound() && bound.isExtendsBound())
2813 bound = upperBound(bound);
2814 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2815 }
2816 }
2817
2818 @Override
2819 public Type visitArrayType(ArrayType t, Void ignored) {
2820 Type elemtype = subst(t.elemtype);
2821 if (elemtype == t.elemtype)
2822 return t;
2823 else
2824 return new ArrayType(upperBound(elemtype), t.tsym);
2825 }
2826
2827 @Override
2828 public Type visitForAll(ForAll t, Void ignored) {
2829 if (Type.containsAny(to, t.tvars)) {
2830 //perform alpha-renaming of free-variables in 't'
2831 //if 'to' types contain variables that are free in 't'
2832 List<Type> freevars = newInstances(t.tvars);
2833 t = new ForAll(freevars,
2834 Types.this.subst(t.qtype, t.tvars, freevars));
2835 }
2836 List<Type> tvars1 = substBounds(t.tvars, from, to);
2837 Type qtype1 = subst(t.qtype);
2838 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2839 return t;
2840 } else if (tvars1 == t.tvars) {
2841 return new ForAll(tvars1, qtype1);
2842 } else {
2843 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2844 }
2845 }
2846
2847 @Override
2848 public Type visitErrorType(ErrorType t, Void ignored) {
2849 return t;
2850 }
2851 }
2852
2853 public List<Type> substBounds(List<Type> tvars,
2854 List<Type> from,
2855 List<Type> to) {
2856 if (tvars.isEmpty())
2857 return tvars;
2858 ListBuffer<Type> newBoundsBuf = lb();
2859 boolean changed = false;
2860 // calculate new bounds
2861 for (Type t : tvars) {
2862 TypeVar tv = (TypeVar) t;
2863 Type bound = subst(tv.bound, from, to);
2864 if (bound != tv.bound)
2865 changed = true;
2866 newBoundsBuf.append(bound);
2867 }
2868 if (!changed)
2869 return tvars;
2870 ListBuffer<Type> newTvars = lb();
2871 // create new type variables without bounds
2872 for (Type t : tvars) {
2873 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2874 }
2875 // the new bounds should use the new type variables in place
2876 // of the old
2877 List<Type> newBounds = newBoundsBuf.toList();
2878 from = tvars;
2879 to = newTvars.toList();
2880 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2881 newBounds.head = subst(newBounds.head, from, to);
2882 }
2883 newBounds = newBoundsBuf.toList();
2884 // set the bounds of new type variables to the new bounds
2885 for (Type t : newTvars.toList()) {
2886 TypeVar tv = (TypeVar) t;
2887 tv.bound = newBounds.head;
2888 newBounds = newBounds.tail;
2889 }
2890 return newTvars.toList();
2891 }
2892
2893 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2894 Type bound1 = subst(t.bound, from, to);
2895 if (bound1 == t.bound)
2896 return t;
2897 else {
2898 // create new type variable without bounds
2899 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2900 // the new bound should use the new type variable in place
2901 // of the old
2902 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2903 return tv;
2904 }
2905 }
2906 // </editor-fold>
2907
2908 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2909 /**
2910 * Does t have the same bounds for quantified variables as s?
2911 */
2912 boolean hasSameBounds(ForAll t, ForAll s) {
2913 List<Type> l1 = t.tvars;
2914 List<Type> l2 = s.tvars;
2915 while (l1.nonEmpty() && l2.nonEmpty() &&
2916 isSameType(l1.head.getUpperBound(),
2917 subst(l2.head.getUpperBound(),
2918 s.tvars,
2919 t.tvars))) {
2920 l1 = l1.tail;
2921 l2 = l2.tail;
2922 }
2923 return l1.isEmpty() && l2.isEmpty();
2924 }
2925 // </editor-fold>
2926
2927 // <editor-fold defaultstate="collapsed" desc="newInstances">
2928 /** Create new vector of type variables from list of variables
2929 * changing all recursive bounds from old to new list.
2930 */
2931 public List<Type> newInstances(List<Type> tvars) {
2932 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2933 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2934 TypeVar tv = (TypeVar) l.head;
2935 tv.bound = subst(tv.bound, tvars, tvars1);
2936 }
2937 return tvars1;
2938 }
2939 private static final Mapping newInstanceFun = new Mapping("newInstanceFun") {
2940 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2941 };
2942 // </editor-fold>
2943
2944 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
2945 return original.accept(methodWithParameters, newParams);
2946 }
2947 // where
2948 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
2949 public Type visitType(Type t, List<Type> newParams) {
2950 throw new IllegalArgumentException("Not a method type: " + t);
2951 }
2952 public Type visitMethodType(MethodType t, List<Type> newParams) {
2953 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
2954 }
2955 public Type visitForAll(ForAll t, List<Type> newParams) {
2956 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
2957 }
2958 };
2959
2960 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
2961 return original.accept(methodWithThrown, newThrown);
2962 }
2963 // where
2964 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
2965 public Type visitType(Type t, List<Type> newThrown) {
2966 throw new IllegalArgumentException("Not a method type: " + t);
2967 }
2968 public Type visitMethodType(MethodType t, List<Type> newThrown) {
2969 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
2970 }
2971 public Type visitForAll(ForAll t, List<Type> newThrown) {
2972 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
2973 }
2974 };
2975
2976 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
2977 return original.accept(methodWithReturn, newReturn);
2978 }
2979 // where
2980 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
2981 public Type visitType(Type t, Type newReturn) {
2982 throw new IllegalArgumentException("Not a method type: " + t);
2983 }
2984 public Type visitMethodType(MethodType t, Type newReturn) {
2985 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym);
2986 }
2987 public Type visitForAll(ForAll t, Type newReturn) {
2988 return new ForAll(t.tvars, t.qtype.accept(this, newReturn));
2989 }
2990 };
2991
2992 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2993 public Type createErrorType(Type originalType) {
2994 return new ErrorType(originalType, syms.errSymbol);
2995 }
2996
2997 public Type createErrorType(ClassSymbol c, Type originalType) {
2998 return new ErrorType(c, originalType);
2999 }
3000
3001 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3002 return new ErrorType(name, container, originalType);
3003 }
3004 // </editor-fold>
3005
3006 // <editor-fold defaultstate="collapsed" desc="rank">
3007 /**
3008 * The rank of a class is the length of the longest path between
3009 * the class and java.lang.Object in the class inheritance
3010 * graph. Undefined for all but reference types.
3011 */
3012 public int rank(Type t) {
3013 t = t.unannotatedType();
3014 switch(t.tag) {
3015 case CLASS: {
3016 ClassType cls = (ClassType)t;
3017 if (cls.rank_field < 0) {
3018 Name fullname = cls.tsym.getQualifiedName();
3019 if (fullname == names.java_lang_Object)
3020 cls.rank_field = 0;
3021 else {
3022 int r = rank(supertype(cls));
3023 for (List<Type> l = interfaces(cls);
3024 l.nonEmpty();
3025 l = l.tail) {
3026 if (rank(l.head) > r)
3027 r = rank(l.head);
3028 }
3029 cls.rank_field = r + 1;
3030 }
3031 }
3032 return cls.rank_field;
3033 }
3034 case TYPEVAR: {
3035 TypeVar tvar = (TypeVar)t;
3036 if (tvar.rank_field < 0) {
3037 int r = rank(supertype(tvar));
3038 for (List<Type> l = interfaces(tvar);
3039 l.nonEmpty();
3040 l = l.tail) {
3041 if (rank(l.head) > r) r = rank(l.head);
3042 }
3043 tvar.rank_field = r + 1;
3044 }
3045 return tvar.rank_field;
3046 }
3047 case ERROR:
3048 return 0;
3049 default:
3050 throw new AssertionError();
3051 }
3052 }
3053 // </editor-fold>
3054
3055 /**
3056 * Helper method for generating a string representation of a given type
3057 * accordingly to a given locale
3058 */
3059 public String toString(Type t, Locale locale) {
3060 return Printer.createStandardPrinter(messages).visit(t, locale);
3061 }
3062
3063 /**
3064 * Helper method for generating a string representation of a given type
3065 * accordingly to a given locale
3066 */
3067 public String toString(Symbol t, Locale locale) {
3068 return Printer.createStandardPrinter(messages).visit(t, locale);
3069 }
3070
3071 // <editor-fold defaultstate="collapsed" desc="toString">
3072 /**
3073 * This toString is slightly more descriptive than the one on Type.
3074 *
3075 * @deprecated Types.toString(Type t, Locale l) provides better support
3076 * for localization
3077 */
3078 @Deprecated
3079 public String toString(Type t) {
3080 if (t.tag == FORALL) {
3081 ForAll forAll = (ForAll)t;
3082 return typaramsString(forAll.tvars) + forAll.qtype;
3083 }
3084 return "" + t;
3085 }
3086 // where
3087 private String typaramsString(List<Type> tvars) {
3088 StringBuilder s = new StringBuilder();
3089 s.append('<');
3090 boolean first = true;
3091 for (Type t : tvars) {
3092 if (!first) s.append(", ");
3093 first = false;
3094 appendTyparamString(((TypeVar)t), s);
3095 }
3096 s.append('>');
3097 return s.toString();
3098 }
3099 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3100 buf.append(t);
3101 if (t.bound == null ||
3102 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
3103 return;
3104 buf.append(" extends "); // Java syntax; no need for i18n
3105 Type bound = t.bound;
3106 if (!bound.isCompound()) {
3107 buf.append(bound);
3108 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3109 buf.append(supertype(t));
3110 for (Type intf : interfaces(t)) {
3111 buf.append('&');
3112 buf.append(intf);
3113 }
3114 } else {
3115 // No superclass was given in bounds.
3116 // In this case, supertype is Object, erasure is first interface.
3117 boolean first = true;
3118 for (Type intf : interfaces(t)) {
3119 if (!first) buf.append('&');
3120 first = false;
3121 buf.append(intf);
3122 }
3123 }
3124 }
3125 // </editor-fold>
3126
3127 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3128 /**
3129 * A cache for closures.
3130 *
3131 * <p>A closure is a list of all the supertypes and interfaces of
3132 * a class or interface type, ordered by ClassSymbol.precedes
3133 * (that is, subclasses come first, arbitrary but fixed
3134 * otherwise).
3135 */
3136 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
3137
3138 /**
3139 * Returns the closure of a class or interface type.
3140 */
3141 public List<Type> closure(Type t) {
3142 List<Type> cl = closureCache.get(t);
3143 if (cl == null) {
3144 Type st = supertype(t);
3145 if (!t.isCompound()) {
3146 if (st.tag == CLASS) {
3147 cl = insert(closure(st), t);
3148 } else if (st.tag == TYPEVAR) {
3149 cl = closure(st).prepend(t);
3150 } else {
3151 cl = List.of(t);
3152 }
3153 } else {
3154 cl = closure(supertype(t));
3155 }
3156 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3157 cl = union(cl, closure(l.head));
3158 closureCache.put(t, cl);
3159 }
3160 return cl;
3161 }
3162
3163 /**
3164 * Insert a type in a closure
3165 */
3166 public List<Type> insert(List<Type> cl, Type t) {
3167 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
3168 return cl.prepend(t);
3169 } else if (cl.head.tsym.precedes(t.tsym, this)) {
3170 return insert(cl.tail, t).prepend(cl.head);
3171 } else {
3172 return cl;
3173 }
3174 }
3175
3176 /**
3177 * Form the union of two closures
3178 */
3179 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3180 if (cl1.isEmpty()) {
3181 return cl2;
3182 } else if (cl2.isEmpty()) {
3183 return cl1;
3184 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
3185 return union(cl1.tail, cl2).prepend(cl1.head);
3186 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3187 return union(cl1, cl2.tail).prepend(cl2.head);
3188 } else {
3189 return union(cl1.tail, cl2.tail).prepend(cl1.head);
3190 }
3191 }
3192
3193 /**
3194 * Intersect two closures
3195 */
3196 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3197 if (cl1 == cl2)
3198 return cl1;
3199 if (cl1.isEmpty() || cl2.isEmpty())
3200 return List.nil();
3201 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3202 return intersect(cl1.tail, cl2);
3203 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3204 return intersect(cl1, cl2.tail);
3205 if (isSameType(cl1.head, cl2.head))
3206 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3207 if (cl1.head.tsym == cl2.head.tsym &&
3208 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
3209 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3210 Type merge = merge(cl1.head,cl2.head);
3211 return intersect(cl1.tail, cl2.tail).prepend(merge);
3212 }
3213 if (cl1.head.isRaw() || cl2.head.isRaw())
3214 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3215 }
3216 return intersect(cl1.tail, cl2.tail);
3217 }
3218 // where
3219 class TypePair {
3220 final Type t1;
3221 final Type t2;
3222 TypePair(Type t1, Type t2) {
3223 this.t1 = t1;
3224 this.t2 = t2;
3225 }
3226 @Override
3227 public int hashCode() {
3228 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3229 }
3230 @Override
3231 public boolean equals(Object obj) {
3232 if (!(obj instanceof TypePair))
3233 return false;
3234 TypePair typePair = (TypePair)obj;
3235 return isSameType(t1, typePair.t1)
3236 && isSameType(t2, typePair.t2);
3237 }
3238 }
3239 Set<TypePair> mergeCache = new HashSet<TypePair>();
3240 private Type merge(Type c1, Type c2) {
3241 ClassType class1 = (ClassType) c1;
3242 List<Type> act1 = class1.getTypeArguments();
3243 ClassType class2 = (ClassType) c2;
3244 List<Type> act2 = class2.getTypeArguments();
3245 ListBuffer<Type> merged = new ListBuffer<Type>();
3246 List<Type> typarams = class1.tsym.type.getTypeArguments();
3247
3248 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3249 if (containsType(act1.head, act2.head)) {
3250 merged.append(act1.head);
3251 } else if (containsType(act2.head, act1.head)) {
3252 merged.append(act2.head);
3253 } else {
3254 TypePair pair = new TypePair(c1, c2);
3255 Type m;
3256 if (mergeCache.add(pair)) {
3257 m = new WildcardType(lub(upperBound(act1.head),
3258 upperBound(act2.head)),
3259 BoundKind.EXTENDS,
3260 syms.boundClass);
3261 mergeCache.remove(pair);
3262 } else {
3263 m = new WildcardType(syms.objectType,
3264 BoundKind.UNBOUND,
3265 syms.boundClass);
3266 }
3267 merged.append(m.withTypeVar(typarams.head));
3268 }
3269 act1 = act1.tail;
3270 act2 = act2.tail;
3271 typarams = typarams.tail;
3272 }
3273 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3274 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
3275 }
3276
3277 /**
3278 * Return the minimum type of a closure, a compound type if no
3279 * unique minimum exists.
3280 */
3281 private Type compoundMin(List<Type> cl) {
3282 if (cl.isEmpty()) return syms.objectType;
3283 List<Type> compound = closureMin(cl);
3284 if (compound.isEmpty())
3285 return null;
3286 else if (compound.tail.isEmpty())
3287 return compound.head;
3288 else
3289 return makeCompoundType(compound);
3290 }
3291
3292 /**
3293 * Return the minimum types of a closure, suitable for computing
3294 * compoundMin or glb.
3295 */
3296 private List<Type> closureMin(List<Type> cl) {
3297 ListBuffer<Type> classes = lb();
3298 ListBuffer<Type> interfaces = lb();
3299 while (!cl.isEmpty()) {
3300 Type current = cl.head;
3301 if (current.isInterface())
3302 interfaces.append(current);
3303 else
3304 classes.append(current);
3305 ListBuffer<Type> candidates = lb();
3306 for (Type t : cl.tail) {
3307 if (!isSubtypeNoCapture(current, t))
3308 candidates.append(t);
3309 }
3310 cl = candidates.toList();
3311 }
3312 return classes.appendList(interfaces).toList();
3313 }
3314
3315 /**
3316 * Return the least upper bound of pair of types. if the lub does
3317 * not exist return null.
3318 */
3319 public Type lub(Type t1, Type t2) {
3320 return lub(List.of(t1, t2));
3321 }
3322
3323 /**
3324 * Return the least upper bound (lub) of set of types. If the lub
3325 * does not exist return the type of null (bottom).
3326 */
3327 public Type lub(List<Type> ts) {
3328 final int ARRAY_BOUND = 1;
3329 final int CLASS_BOUND = 2;
3330 int boundkind = 0;
3331 for (Type t : ts) {
3332 switch (t.tag) {
3333 case CLASS:
3334 boundkind |= CLASS_BOUND;
3335 break;
3336 case ARRAY:
3337 boundkind |= ARRAY_BOUND;
3338 break;
3339 case TYPEVAR:
3340 do {
3341 t = t.getUpperBound();
3342 } while (t.tag == TYPEVAR);
3343 if (t.tag == ARRAY) {
3344 boundkind |= ARRAY_BOUND;
3345 } else {
3346 boundkind |= CLASS_BOUND;
3347 }
3348 break;
3349 default:
3350 if (t.isPrimitive())
3351 return syms.errType;
3352 }
3353 }
3354 switch (boundkind) {
3355 case 0:
3356 return syms.botType;
3357
3358 case ARRAY_BOUND:
3359 // calculate lub(A[], B[])
3360 List<Type> elements = Type.map(ts, elemTypeFun);
3361 for (Type t : elements) {
3362 if (t.isPrimitive()) {
3363 // if a primitive type is found, then return
3364 // arraySuperType unless all the types are the
3365 // same
3366 Type first = ts.head;
3367 for (Type s : ts.tail) {
3368 if (!isSameType(first, s)) {
3369 // lub(int[], B[]) is Cloneable & Serializable
3370 return arraySuperType();
3371 }
3372 }
3373 // all the array types are the same, return one
3374 // lub(int[], int[]) is int[]
3375 return first;
3376 }
3377 }
3378 // lub(A[], B[]) is lub(A, B)[]
3379 return new ArrayType(lub(elements), syms.arrayClass);
3380
3381 case CLASS_BOUND:
3382 // calculate lub(A, B)
3383 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
3384 ts = ts.tail;
3385 Assert.check(!ts.isEmpty());
3386 //step 1 - compute erased candidate set (EC)
3387 List<Type> cl = erasedSupertypes(ts.head);
3388 for (Type t : ts.tail) {
3389 if (t.tag == CLASS || t.tag == TYPEVAR)
3390 cl = intersect(cl, erasedSupertypes(t));
3391 }
3392 //step 2 - compute minimal erased candidate set (MEC)
3393 List<Type> mec = closureMin(cl);
3394 //step 3 - for each element G in MEC, compute lci(Inv(G))
3395 List<Type> candidates = List.nil();
3396 for (Type erasedSupertype : mec) {
3397 List<Type> lci = List.of(asSuper(ts.head, erasedSupertype.tsym));
3398 for (Type t : ts) {
3399 lci = intersect(lci, List.of(asSuper(t, erasedSupertype.tsym)));
3400 }
3401 candidates = candidates.appendList(lci);
3402 }
3403 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
3404 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
3405 return compoundMin(candidates);
3406
3407 default:
3408 // calculate lub(A, B[])
3409 List<Type> classes = List.of(arraySuperType());
3410 for (Type t : ts) {
3411 if (t.tag != ARRAY) // Filter out any arrays
3412 classes = classes.prepend(t);
3413 }
3414 // lub(A, B[]) is lub(A, arraySuperType)
3415 return lub(classes);
3416 }
3417 }
3418 // where
3419 List<Type> erasedSupertypes(Type t) {
3420 ListBuffer<Type> buf = lb();
3421 for (Type sup : closure(t)) {
3422 if (sup.tag == TYPEVAR) {
3423 buf.append(sup);
3424 } else {
3425 buf.append(erasure(sup));
3426 }
3427 }
3428 return buf.toList();
3429 }
3430
3431 private Type arraySuperType = null;
3432 private Type arraySuperType() {
3433 // initialized lazily to avoid problems during compiler startup
3434 if (arraySuperType == null) {
3435 synchronized (this) {
3436 if (arraySuperType == null) {
3437 // JLS 10.8: all arrays implement Cloneable and Serializable.
3438 arraySuperType = makeCompoundType(List.of(syms.serializableType,
3439 syms.cloneableType), true);
3440 }
3441 }
3442 }
3443 return arraySuperType;
3444 }
3445 // </editor-fold>
3446
3447 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
3448 public Type glb(List<Type> ts) {
3449 Type t1 = ts.head;
3450 for (Type t2 : ts.tail) {
3451 if (t1.isErroneous())
3452 return t1;
3453 t1 = glb(t1, t2);
3454 }
3455 return t1;
3456 }
3457 //where
3458 public Type glb(Type t, Type s) {
3459 if (s == null)
3460 return t;
3461 else if (t.isPrimitive() || s.isPrimitive())
3462 return syms.errType;
3463 else if (isSubtypeNoCapture(t, s))
3464 return t;
3465 else if (isSubtypeNoCapture(s, t))
3466 return s;
3467
3468 List<Type> closure = union(closure(t), closure(s));
3469 List<Type> bounds = closureMin(closure);
3470
3471 if (bounds.isEmpty()) { // length == 0
3472 return syms.objectType;
3473 } else if (bounds.tail.isEmpty()) { // length == 1
3474 return bounds.head;
3475 } else { // length > 1
3476 int classCount = 0;
3477 for (Type bound : bounds)
3478 if (!bound.isInterface())
3479 classCount++;
3480 if (classCount > 1)
3481 return createErrorType(t);
3482 }
3483 return makeCompoundType(bounds);
3484 }
3485 // </editor-fold>
3486
3487 // <editor-fold defaultstate="collapsed" desc="hashCode">
3488 /**
3489 * Compute a hash code on a type.
3490 */
3491 public int hashCode(Type t) {
3492 return hashCode.visit(t);
3493 }
3494 // where
3495 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
3496
3497 public Integer visitType(Type t, Void ignored) {
3498 return t.tag.ordinal();
3499 }
3500
3501 @Override
3502 public Integer visitClassType(ClassType t, Void ignored) {
3503 int result = visit(t.getEnclosingType());
3504 result *= 127;
3505 result += t.tsym.flatName().hashCode();
3506 for (Type s : t.getTypeArguments()) {
3507 result *= 127;
3508 result += visit(s);
3509 }
3510 return result;
3511 }
3512
3513 @Override
3514 public Integer visitMethodType(MethodType t, Void ignored) {
3515 int h = METHOD.ordinal();
3516 for (List<Type> thisargs = t.argtypes;
3517 thisargs.tail != null;
3518 thisargs = thisargs.tail)
3519 h = (h << 5) + visit(thisargs.head);
3520 return (h << 5) + visit(t.restype);
3521 }
3522
3523 @Override
3524 public Integer visitWildcardType(WildcardType t, Void ignored) {
3525 int result = t.kind.hashCode();
3526 if (t.type != null) {
3527 result *= 127;
3528 result += visit(t.type);
3529 }
3530 return result;
3531 }
3532
3533 @Override
3534 public Integer visitArrayType(ArrayType t, Void ignored) {
3535 return visit(t.elemtype) + 12;
3536 }
3537
3538 @Override
3539 public Integer visitTypeVar(TypeVar t, Void ignored) {
3540 return System.identityHashCode(t.tsym);
3541 }
3542
3543 @Override
3544 public Integer visitUndetVar(UndetVar t, Void ignored) {
3545 return System.identityHashCode(t);
3546 }
3547
3548 @Override
3549 public Integer visitErrorType(ErrorType t, Void ignored) {
3550 return 0;
3551 }
3552 };
3553 // </editor-fold>
3554
3555 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
3556 /**
3557 * Does t have a result that is a subtype of the result type of s,
3558 * suitable for covariant returns? It is assumed that both types
3559 * are (possibly polymorphic) method types. Monomorphic method
3560 * types are handled in the obvious way. Polymorphic method types
3561 * require renaming all type variables of one to corresponding
3562 * type variables in the other, where correspondence is by
3563 * position in the type parameter list. */
3564 public boolean resultSubtype(Type t, Type s, Warner warner) {
3565 List<Type> tvars = t.getTypeArguments();
3566 List<Type> svars = s.getTypeArguments();
3567 Type tres = t.getReturnType();
3568 Type sres = subst(s.getReturnType(), svars, tvars);
3569 return covariantReturnType(tres, sres, warner);
3570 }
3571
3572 /**
3573 * Return-Type-Substitutable.
3574 * @jls section 8.4.5
3575 */
3576 public boolean returnTypeSubstitutable(Type r1, Type r2) {
3577 if (hasSameArgs(r1, r2))
3578 return resultSubtype(r1, r2, noWarnings);
3579 else
3580 return covariantReturnType(r1.getReturnType(),
3581 erasure(r2.getReturnType()),
3582 noWarnings);
3583 }
3584
3585 public boolean returnTypeSubstitutable(Type r1,
3586 Type r2, Type r2res,
3587 Warner warner) {
3588 if (isSameType(r1.getReturnType(), r2res))
3589 return true;
3590 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
3591 return false;
3592
3593 if (hasSameArgs(r1, r2))
3594 return covariantReturnType(r1.getReturnType(), r2res, warner);
3595 if (!allowCovariantReturns)
3596 return false;
3597 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
3598 return true;
3599 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
3600 return false;
3601 warner.warn(LintCategory.UNCHECKED);
3602 return true;
3603 }
3604
3605 /**
3606 * Is t an appropriate return type in an overrider for a
3607 * method that returns s?
3608 */
3609 public boolean covariantReturnType(Type t, Type s, Warner warner) {
3610 return
3611 isSameType(t, s) ||
3612 allowCovariantReturns &&
3613 !t.isPrimitive() &&
3614 !s.isPrimitive() &&
3615 isAssignable(t, s, warner);
3616 }
3617 // </editor-fold>
3618
3619 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
3620 /**
3621 * Return the class that boxes the given primitive.
3622 */
3623 public ClassSymbol boxedClass(Type t) {
3624 return reader.enterClass(syms.boxedName[t.tag.ordinal()]);
3625 }
3626
3627 /**
3628 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
3629 */
3630 public Type boxedTypeOrType(Type t) {
3631 return t.isPrimitive() ?
3632 boxedClass(t).type :
3633 t;
3634 }
3635
3636 /**
3637 * Return the primitive type corresponding to a boxed type.
3638 */
3639 public Type unboxedType(Type t) {
3640 if (allowBoxing) {
3641 for (int i=0; i<syms.boxedName.length; i++) {
3642 Name box = syms.boxedName[i];
3643 if (box != null &&
3644 asSuper(t, reader.enterClass(box)) != null)
3645 return syms.typeOfTag[i];
3646 }
3647 }
3648 return Type.noType;
3649 }
3650
3651 /**
3652 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
3653 */
3654 public Type unboxedTypeOrType(Type t) {
3655 Type unboxedType = unboxedType(t);
3656 return unboxedType.tag == NONE ? t : unboxedType;
3657 }
3658 // </editor-fold>
3659
3660 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3661 /*
3662 * JLS 5.1.10 Capture Conversion:
3663 *
3664 * Let G name a generic type declaration with n formal type
3665 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3666 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3667 * where, for 1 <= i <= n:
3668 *
3669 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3670 * Si is a fresh type variable whose upper bound is
3671 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3672 * type.
3673 *
3674 * + If Ti is a wildcard type argument of the form ? extends Bi,
3675 * then Si is a fresh type variable whose upper bound is
3676 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3677 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3678 * a compile-time error if for any two classes (not interfaces)
3679 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3680 *
3681 * + If Ti is a wildcard type argument of the form ? super Bi,
3682 * then Si is a fresh type variable whose upper bound is
3683 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3684 *
3685 * + Otherwise, Si = Ti.
3686 *
3687 * Capture conversion on any type other than a parameterized type
3688 * (4.5) acts as an identity conversion (5.1.1). Capture
3689 * conversions never require a special action at run time and
3690 * therefore never throw an exception at run time.
3691 *
3692 * Capture conversion is not applied recursively.
3693 */
3694 /**
3695 * Capture conversion as specified by the JLS.
3696 */
3697
3698 public List<Type> capture(List<Type> ts) {
3699 List<Type> buf = List.nil();
3700 for (Type t : ts) {
3701 buf = buf.prepend(capture(t));
3702 }
3703 return buf.reverse();
3704 }
3705 public Type capture(Type t) {
3706 if (t.tag != CLASS)
3707 return t;
3708 if (t.getEnclosingType() != Type.noType) {
3709 Type capturedEncl = capture(t.getEnclosingType());
3710 if (capturedEncl != t.getEnclosingType()) {
3711 Type type1 = memberType(capturedEncl, t.tsym);
3712 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3713 }
3714 }
3715 t = t.unannotatedType();
3716 ClassType cls = (ClassType)t;
3717 if (cls.isRaw() || !cls.isParameterized())
3718 return cls;
3719
3720 ClassType G = (ClassType)cls.asElement().asType();
3721 List<Type> A = G.getTypeArguments();
3722 List<Type> T = cls.getTypeArguments();
3723 List<Type> S = freshTypeVariables(T);
3724
3725 List<Type> currentA = A;
3726 List<Type> currentT = T;
3727 List<Type> currentS = S;
3728 boolean captured = false;
3729 while (!currentA.isEmpty() &&
3730 !currentT.isEmpty() &&
3731 !currentS.isEmpty()) {
3732 if (currentS.head != currentT.head) {
3733 captured = true;
3734 WildcardType Ti = (WildcardType)currentT.head;
3735 Type Ui = currentA.head.getUpperBound();
3736 CapturedType Si = (CapturedType)currentS.head;
3737 if (Ui == null)
3738 Ui = syms.objectType;
3739 switch (Ti.kind) {
3740 case UNBOUND:
3741 Si.bound = subst(Ui, A, S);
3742 Si.lower = syms.botType;
3743 break;
3744 case EXTENDS:
3745 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3746 Si.lower = syms.botType;
3747 break;
3748 case SUPER:
3749 Si.bound = subst(Ui, A, S);
3750 Si.lower = Ti.getSuperBound();
3751 break;
3752 }
3753 if (Si.bound == Si.lower)
3754 currentS.head = Si.bound;
3755 }
3756 currentA = currentA.tail;
3757 currentT = currentT.tail;
3758 currentS = currentS.tail;
3759 }
3760 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3761 return erasure(t); // some "rare" type involved
3762
3763 if (captured)
3764 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3765 else
3766 return t;
3767 }
3768 // where
3769 public List<Type> freshTypeVariables(List<Type> types) {
3770 ListBuffer<Type> result = lb();
3771 for (Type t : types) {
3772 if (t.tag == WILDCARD) {
3773 Type bound = ((WildcardType)t).getExtendsBound();
3774 if (bound == null)
3775 bound = syms.objectType;
3776 result.append(new CapturedType(capturedName,
3777 syms.noSymbol,
3778 bound,
3779 syms.botType,
3780 (WildcardType)t));
3781 } else {
3782 result.append(t);
3783 }
3784 }
3785 return result.toList();
3786 }
3787 // </editor-fold>
3788
3789 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3790 private List<Type> upperBounds(List<Type> ss) {
3791 if (ss.isEmpty()) return ss;
3792 Type head = upperBound(ss.head);
3793 List<Type> tail = upperBounds(ss.tail);
3794 if (head != ss.head || tail != ss.tail)
3795 return tail.prepend(head);
3796 else
3797 return ss;
3798 }
3799
3800 private boolean sideCast(Type from, Type to, Warner warn) {
3801 // We are casting from type $from$ to type $to$, which are
3802 // non-final unrelated types. This method
3803 // tries to reject a cast by transferring type parameters
3804 // from $to$ to $from$ by common superinterfaces.
3805 boolean reverse = false;
3806 Type target = to;
3807 if ((to.tsym.flags() & INTERFACE) == 0) {
3808 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3809 reverse = true;
3810 to = from;
3811 from = target;
3812 }
3813 List<Type> commonSupers = superClosure(to, erasure(from));
3814 boolean giveWarning = commonSupers.isEmpty();
3815 // The arguments to the supers could be unified here to
3816 // get a more accurate analysis
3817 while (commonSupers.nonEmpty()) {
3818 Type t1 = asSuper(from, commonSupers.head.tsym);
3819 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3820 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3821 return false;
3822 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3823 commonSupers = commonSupers.tail;
3824 }
3825 if (giveWarning && !isReifiable(reverse ? from : to))
3826 warn.warn(LintCategory.UNCHECKED);
3827 if (!allowCovariantReturns)
3828 // reject if there is a common method signature with
3829 // incompatible return types.
3830 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3831 return true;
3832 }
3833
3834 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3835 // We are casting from type $from$ to type $to$, which are
3836 // unrelated types one of which is final and the other of
3837 // which is an interface. This method
3838 // tries to reject a cast by transferring type parameters
3839 // from the final class to the interface.
3840 boolean reverse = false;
3841 Type target = to;
3842 if ((to.tsym.flags() & INTERFACE) == 0) {
3843 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3844 reverse = true;
3845 to = from;
3846 from = target;
3847 }
3848 Assert.check((from.tsym.flags() & FINAL) != 0);
3849 Type t1 = asSuper(from, to.tsym);
3850 if (t1 == null) return false;
3851 Type t2 = to;
3852 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3853 return false;
3854 if (!allowCovariantReturns)
3855 // reject if there is a common method signature with
3856 // incompatible return types.
3857 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3858 if (!isReifiable(target) &&
3859 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3860 warn.warn(LintCategory.UNCHECKED);
3861 return true;
3862 }
3863
3864 private boolean giveWarning(Type from, Type to) {
3865 List<Type> bounds = to.isCompound() ?
3866 ((IntersectionClassType)to).getComponents() : List.of(to);
3867 for (Type b : bounds) {
3868 Type subFrom = asSub(from, b.tsym);
3869 if (b.isParameterized() &&
3870 (!(isUnbounded(b) ||
3871 isSubtype(from, b) ||
3872 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
3873 return true;
3874 }
3875 }
3876 return false;
3877 }
3878
3879 private List<Type> superClosure(Type t, Type s) {
3880 List<Type> cl = List.nil();
3881 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3882 if (isSubtype(s, erasure(l.head))) {
3883 cl = insert(cl, l.head);
3884 } else {
3885 cl = union(cl, superClosure(l.head, s));
3886 }
3887 }
3888 return cl;
3889 }
3890
3891 private boolean containsTypeEquivalent(Type t, Type s) {
3892 return
3893 isSameType(t, s) || // shortcut
3894 containsType(t, s) && containsType(s, t);
3895 }
3896
3897 // <editor-fold defaultstate="collapsed" desc="adapt">
3898 /**
3899 * Adapt a type by computing a substitution which maps a source
3900 * type to a target type.
3901 *
3902 * @param source the source type
3903 * @param target the target type
3904 * @param from the type variables of the computed substitution
3905 * @param to the types of the computed substitution.
3906 */
3907 public void adapt(Type source,
3908 Type target,
3909 ListBuffer<Type> from,
3910 ListBuffer<Type> to) throws AdaptFailure {
3911 new Adapter(from, to).adapt(source, target);
3912 }
3913
3914 class Adapter extends SimpleVisitor<Void, Type> {
3915
3916 ListBuffer<Type> from;
3917 ListBuffer<Type> to;
3918 Map<Symbol,Type> mapping;
3919
3920 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3921 this.from = from;
3922 this.to = to;
3923 mapping = new HashMap<Symbol,Type>();
3924 }
3925
3926 public void adapt(Type source, Type target) throws AdaptFailure {
3927 visit(source, target);
3928 List<Type> fromList = from.toList();
3929 List<Type> toList = to.toList();
3930 while (!fromList.isEmpty()) {
3931 Type val = mapping.get(fromList.head.tsym);
3932 if (toList.head != val)
3933 toList.head = val;
3934 fromList = fromList.tail;
3935 toList = toList.tail;
3936 }
3937 }
3938
3939 @Override
3940 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3941 if (target.tag == CLASS)
3942 adaptRecursive(source.allparams(), target.allparams());
3943 return null;
3944 }
3945
3946 @Override
3947 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3948 if (target.tag == ARRAY)
3949 adaptRecursive(elemtype(source), elemtype(target));
3950 return null;
3951 }
3952
3953 @Override
3954 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3955 if (source.isExtendsBound())
3956 adaptRecursive(upperBound(source), upperBound(target));
3957 else if (source.isSuperBound())
3958 adaptRecursive(lowerBound(source), lowerBound(target));
3959 return null;
3960 }
3961
3962 @Override
3963 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3964 // Check to see if there is
3965 // already a mapping for $source$, in which case
3966 // the old mapping will be merged with the new
3967 Type val = mapping.get(source.tsym);
3968 if (val != null) {
3969 if (val.isSuperBound() && target.isSuperBound()) {
3970 val = isSubtype(lowerBound(val), lowerBound(target))
3971 ? target : val;
3972 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3973 val = isSubtype(upperBound(val), upperBound(target))
3974 ? val : target;
3975 } else if (!isSameType(val, target)) {
3976 throw new AdaptFailure();
3977 }
3978 } else {
3979 val = target;
3980 from.append(source);
3981 to.append(target);
3982 }
3983 mapping.put(source.tsym, val);
3984 return null;
3985 }
3986
3987 @Override
3988 public Void visitType(Type source, Type target) {
3989 return null;
3990 }
3991
3992 private Set<TypePair> cache = new HashSet<TypePair>();
3993
3994 private void adaptRecursive(Type source, Type target) {
3995 TypePair pair = new TypePair(source, target);
3996 if (cache.add(pair)) {
3997 try {
3998 visit(source, target);
3999 } finally {
4000 cache.remove(pair);
4001 }
4002 }
4003 }
4004
4005 private void adaptRecursive(List<Type> source, List<Type> target) {
4006 if (source.length() == target.length()) {
4007 while (source.nonEmpty()) {
4008 adaptRecursive(source.head, target.head);
4009 source = source.tail;
4010 target = target.tail;
4011 }
4012 }
4013 }
4014 }
4015
4016 public static class AdaptFailure extends RuntimeException {
4017 static final long serialVersionUID = -7490231548272701566L;
4018 }
4019
4020 private void adaptSelf(Type t,
4021 ListBuffer<Type> from,
4022 ListBuffer<Type> to) {
4023 try {
4024 //if (t.tsym.type != t)
4025 adapt(t.tsym.type, t, from, to);
4026 } catch (AdaptFailure ex) {
4027 // Adapt should never fail calculating a mapping from
4028 // t.tsym.type to t as there can be no merge problem.
4029 throw new AssertionError(ex);
4030 }
4031 }
4032 // </editor-fold>
4033
4034 /**
4035 * Rewrite all type variables (universal quantifiers) in the given
4036 * type to wildcards (existential quantifiers). This is used to
4037 * determine if a cast is allowed. For example, if high is true
4038 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4039 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4040 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4041 * List<Integer>} with a warning.
4042 * @param t a type
4043 * @param high if true return an upper bound; otherwise a lower
4044 * bound
4045 * @param rewriteTypeVars only rewrite captured wildcards if false;
4046 * otherwise rewrite all type variables
4047 * @return the type rewritten with wildcards (existential
4048 * quantifiers) only
4049 */
4050 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4051 return new Rewriter(high, rewriteTypeVars).visit(t);
4052 }
4053
4054 class Rewriter extends UnaryVisitor<Type> {
4055
4056 boolean high;
4057 boolean rewriteTypeVars;
4058
4059 Rewriter(boolean high, boolean rewriteTypeVars) {
4060 this.high = high;
4061 this.rewriteTypeVars = rewriteTypeVars;
4062 }
4063
4064 @Override
4065 public Type visitClassType(ClassType t, Void s) {
4066 ListBuffer<Type> rewritten = new ListBuffer<Type>();
4067 boolean changed = false;
4068 for (Type arg : t.allparams()) {
4069 Type bound = visit(arg);
4070 if (arg != bound) {
4071 changed = true;
4072 }
4073 rewritten.append(bound);
4074 }
4075 if (changed)
4076 return subst(t.tsym.type,
4077 t.tsym.type.allparams(),
4078 rewritten.toList());
4079 else
4080 return t;
4081 }
4082
4083 public Type visitType(Type t, Void s) {
4084 return high ? upperBound(t) : lowerBound(t);
4085 }
4086
4087 @Override
4088 public Type visitCapturedType(CapturedType t, Void s) {
4089 Type w_bound = t.wildcard.type;
4090 Type bound = w_bound.contains(t) ?
4091 erasure(w_bound) :
4092 visit(w_bound);
4093 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4094 }
4095
4096 @Override
4097 public Type visitTypeVar(TypeVar t, Void s) {
4098 if (rewriteTypeVars) {
4099 Type bound = t.bound.contains(t) ?
4100 erasure(t.bound) :
4101 visit(t.bound);
4102 return rewriteAsWildcardType(bound, t, EXTENDS);
4103 } else {
4104 return t;
4105 }
4106 }
4107
4108 @Override
4109 public Type visitWildcardType(WildcardType t, Void s) {
4110 Type bound2 = visit(t.type);
4111 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4112 }
4113
4114 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4115 switch (bk) {
4116 case EXTENDS: return high ?
4117 makeExtendsWildcard(B(bound), formal) :
4118 makeExtendsWildcard(syms.objectType, formal);
4119 case SUPER: return high ?
4120 makeSuperWildcard(syms.botType, formal) :
4121 makeSuperWildcard(B(bound), formal);
4122 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4123 default:
4124 Assert.error("Invalid bound kind " + bk);
4125 return null;
4126 }
4127 }
4128
4129 Type B(Type t) {
4130 while (t.tag == WILDCARD) {
4131 WildcardType w = (WildcardType)t;
4132 t = high ?
4133 w.getExtendsBound() :
4134 w.getSuperBound();
4135 if (t == null) {
4136 t = high ? syms.objectType : syms.botType;
4137 }
4138 }
4139 return t;
4140 }
4141 }
4142
4143
4144 /**
4145 * Create a wildcard with the given upper (extends) bound; create
4146 * an unbounded wildcard if bound is Object.
4147 *
4148 * @param bound the upper bound
4149 * @param formal the formal type parameter that will be
4150 * substituted by the wildcard
4151 */
4152 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4153 if (bound == syms.objectType) {
4154 return new WildcardType(syms.objectType,
4155 BoundKind.UNBOUND,
4156 syms.boundClass,
4157 formal);
4158 } else {
4159 return new WildcardType(bound,
4160 BoundKind.EXTENDS,
4161 syms.boundClass,
4162 formal);
4163 }
4164 }
4165
4166 /**
4167 * Create a wildcard with the given lower (super) bound; create an
4168 * unbounded wildcard if bound is bottom (type of {@code null}).
4169 *
4170 * @param bound the lower bound
4171 * @param formal the formal type parameter that will be
4172 * substituted by the wildcard
4173 */
4174 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4175 if (bound.tag == BOT) {
4176 return new WildcardType(syms.objectType,
4177 BoundKind.UNBOUND,
4178 syms.boundClass,
4179 formal);
4180 } else {
4181 return new WildcardType(bound,
4182 BoundKind.SUPER,
4183 syms.boundClass,
4184 formal);
4185 }
4186 }
4187
4188 /**
4189 * A wrapper for a type that allows use in sets.
4190 */
4191 public static class UniqueType {
4192 public final Type type;
4193 final Types types;
4194
4195 public UniqueType(Type type, Types types) {
4196 this.type = type;
4197 this.types = types;
4198 }
4199
4200 public int hashCode() {
4201 return types.hashCode(type);
4202 }
4203
4204 public boolean equals(Object obj) {
4205 return (obj instanceof UniqueType) &&
4206 types.isSameType(type, ((UniqueType)obj).type);
4207 }
4208
4209 public String toString() {
4210 return type.toString();
4211 }
4212
4213 }
4214 // </editor-fold>
4215
4216 // <editor-fold defaultstate="collapsed" desc="Visitors">
4217 /**
4218 * A default visitor for types. All visitor methods except
4219 * visitType are implemented by delegating to visitType. Concrete
4220 * subclasses must provide an implementation of visitType and can
4221 * override other methods as needed.
4222 *
4223 * @param <R> the return type of the operation implemented by this
4224 * visitor; use Void if no return type is needed.
4225 * @param <S> the type of the second argument (the first being the
4226 * type itself) of the operation implemented by this visitor; use
4227 * Void if a second argument is not needed.
4228 */
4229 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4230 final public R visit(Type t, S s) { return t.accept(this, s); }
4231 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4232 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4233 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4234 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4235 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4236 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4237 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4238 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4239 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4240 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4241 // Pretend annotations don't exist
4242 public R visitAnnotatedType(AnnotatedType t, S s) { return visit(t.underlyingType, s); }
4243 }
4244
4245 /**
4246 * A default visitor for symbols. All visitor methods except
4247 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4248 * subclasses must provide an implementation of visitSymbol and can
4249 * override other methods as needed.
4250 *
4251 * @param <R> the return type of the operation implemented by this
4252 * visitor; use Void if no return type is needed.
4253 * @param <S> the type of the second argument (the first being the
4254 * symbol itself) of the operation implemented by this visitor; use
4255 * Void if a second argument is not needed.
4256 */
4257 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4258 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
4259 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4260 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4261 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4262 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4263 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4264 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4265 }
4266
4267 /**
4268 * A <em>simple</em> visitor for types. This visitor is simple as
4269 * captured wildcards, for-all types (generic methods), and
4270 * undetermined type variables (part of inference) are hidden.
4271 * Captured wildcards are hidden by treating them as type
4272 * variables and the rest are hidden by visiting their qtypes.
4273 *
4274 * @param <R> the return type of the operation implemented by this
4275 * visitor; use Void if no return type is needed.
4276 * @param <S> the type of the second argument (the first being the
4277 * type itself) of the operation implemented by this visitor; use
4278 * Void if a second argument is not needed.
4279 */
4280 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4281 @Override
4282 public R visitCapturedType(CapturedType t, S s) {
4283 return visitTypeVar(t, s);
4284 }
4285 @Override
4286 public R visitForAll(ForAll t, S s) {
4287 return visit(t.qtype, s);
4288 }
4289 @Override
4290 public R visitUndetVar(UndetVar t, S s) {
4291 return visit(t.qtype, s);
4292 }
4293 }
4294
4295 /**
4296 * A plain relation on types. That is a 2-ary function on the
4297 * form Type × Type → Boolean.
4298 * <!-- In plain text: Type x Type -> Boolean -->
4299 */
4300 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4301
4302 /**
4303 * A convenience visitor for implementing operations that only
4304 * require one argument (the type itself), that is, unary
4305 * operations.
4306 *
4307 * @param <R> the return type of the operation implemented by this
4308 * visitor; use Void if no return type is needed.
4309 */
4310 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4311 final public R visit(Type t) { return t.accept(this, null); }
4312 }
4313
4314 /**
4315 * A visitor for implementing a mapping from types to types. The
4316 * default behavior of this class is to implement the identity
4317 * mapping (mapping a type to itself). This can be overridden in
4318 * subclasses.
4319 *
4320 * @param <S> the type of the second argument (the first being the
4321 * type itself) of this mapping; use Void if a second argument is
4322 * not needed.
4323 */
4324 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4325 final public Type visit(Type t) { return t.accept(this, null); }
4326 public Type visitType(Type t, S s) { return t; }
4327 }
4328 // </editor-fold>
4329
4330
4331 // <editor-fold defaultstate="collapsed" desc="Annotation support">
4332
4333 public RetentionPolicy getRetention(Attribute.Compound a) {
4334 return getRetention(a.type.tsym);
4335 }
4336
4337 public RetentionPolicy getRetention(Symbol sym) {
4338 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
4339 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
4340 if (c != null) {
4341 Attribute value = c.member(names.value);
4342 if (value != null && value instanceof Attribute.Enum) {
4343 Name levelName = ((Attribute.Enum)value).value.name;
4344 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
4345 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
4346 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
4347 else ;// /* fail soft */ throw new AssertionError(levelName);
4348 }
4349 }
4350 return vis;
4351 }
4352 // </editor-fold>
4353
4354 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
4355
4356 public static abstract class SignatureGenerator {
4357
4358 private final Types types;
4359
4360 protected abstract void append(char ch);
4361 protected abstract void append(byte[] ba);
4362 protected abstract void append(Name name);
4363 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
4364
4365 protected SignatureGenerator(Types types) {
4366 this.types = types;
4367 }
4368
4369 /**
4370 * Assemble signature of given type in string buffer.
4371 */
4372 public void assembleSig(Type type) {
4373 type = type.unannotatedType();
4374 switch (type.getTag()) {
4375 case BYTE:
4376 append('B');
4377 break;
4378 case SHORT:
4379 append('S');
4380 break;
4381 case CHAR:
4382 append('C');
4383 break;
4384 case INT:
4385 append('I');
4386 break;
4387 case LONG:
4388 append('J');
4389 break;
4390 case FLOAT:
4391 append('F');
4392 break;
4393 case DOUBLE:
4394 append('D');
4395 break;
4396 case BOOLEAN:
4397 append('Z');
4398 break;
4399 case VOID:
4400 append('V');
4401 break;
4402 case CLASS:
4403 append('L');
4404 assembleClassSig(type);
4405 append(';');
4406 break;
4407 case ARRAY:
4408 ArrayType at = (ArrayType) type;
4409 append('[');
4410 assembleSig(at.elemtype);
4411 break;
4412 case METHOD:
4413 MethodType mt = (MethodType) type;
4414 append('(');
4415 assembleSig(mt.argtypes);
4416 append(')');
4417 assembleSig(mt.restype);
4418 if (hasTypeVar(mt.thrown)) {
4419 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
4420 append('^');
4421 assembleSig(l.head);
4422 }
4423 }
4424 break;
4425 case WILDCARD: {
4426 Type.WildcardType ta = (Type.WildcardType) type;
4427 switch (ta.kind) {
4428 case SUPER:
4429 append('-');
4430 assembleSig(ta.type);
4431 break;
4432 case EXTENDS:
4433 append('+');
4434 assembleSig(ta.type);
4435 break;
4436 case UNBOUND:
4437 append('*');
4438 break;
4439 default:
4440 throw new AssertionError(ta.kind);
4441 }
4442 break;
4443 }
4444 case TYPEVAR:
4445 append('T');
4446 append(type.tsym.name);
4447 append(';');
4448 break;
4449 case FORALL:
4450 Type.ForAll ft = (Type.ForAll) type;
4451 assembleParamsSig(ft.tvars);
4452 assembleSig(ft.qtype);
4453 break;
4454 default:
4455 throw new AssertionError("typeSig " + type.getTag());
4456 }
4457 }
4458
4459 public boolean hasTypeVar(List<Type> l) {
4460 while (l.nonEmpty()) {
4461 if (l.head.hasTag(TypeTag.TYPEVAR)) {
4462 return true;
4463 }
4464 l = l.tail;
4465 }
4466 return false;
4467 }
4468
4469 public void assembleClassSig(Type type) {
4470 type = type.unannotatedType();
4471 ClassType ct = (ClassType) type;
4472 ClassSymbol c = (ClassSymbol) ct.tsym;
4473 classReference(c);
4474 Type outer = ct.getEnclosingType();
4475 if (outer.allparams().nonEmpty()) {
4476 boolean rawOuter =
4477 c.owner.kind == Kinds.MTH || // either a local class
4478 c.name == types.names.empty; // or anonymous
4479 assembleClassSig(rawOuter
4480 ? types.erasure(outer)
4481 : outer);
4482 append('.');
4483 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
4484 append(rawOuter
4485 ? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength())
4486 : c.name);
4487 } else {
4488 append(externalize(c.flatname));
4489 }
4490 if (ct.getTypeArguments().nonEmpty()) {
4491 append('<');
4492 assembleSig(ct.getTypeArguments());
4493 append('>');
4494 }
4495 }
4496
4497 public void assembleParamsSig(List<Type> typarams) {
4498 append('<');
4499 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
4500 Type.TypeVar tvar = (Type.TypeVar) ts.head;
4501 append(tvar.tsym.name);
4502 List<Type> bounds = types.getBounds(tvar);
4503 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
4504 append(':');
4505 }
4506 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
4507 append(':');
4508 assembleSig(l.head);
4509 }
4510 }
4511 append('>');
4512 }
4513
4514 private void assembleSig(List<Type> types) {
4515 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
4516 assembleSig(ts.head);
4517 }
4518 }
4519 }
4520 // </editor-fold>
4521 }