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.HashSet;
30 import java.util.HashMap;
31 import java.util.Locale;
32 import java.util.Map;
33 import java.util.Set;
34 import java.util.WeakHashMap;
35
36 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
37 import com.sun.tools.javac.code.Lint.LintCategory;
38 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
39 import com.sun.tools.javac.comp.Check;
40 import com.sun.tools.javac.jvm.ClassReader;
41 import com.sun.tools.javac.util.*;
42 import static com.sun.tools.javac.code.BoundKind.*;
43 import static com.sun.tools.javac.code.Flags.*;
44 import static com.sun.tools.javac.code.Scope.*;
45 import static com.sun.tools.javac.code.Symbol.*;
46 import static com.sun.tools.javac.code.Type.*;
47 import static com.sun.tools.javac.code.TypeTag.*;
48 import static com.sun.tools.javac.jvm.ClassFile.externalize;
49 import static com.sun.tools.javac.util.ListBuffer.lb;
50
51 /**
52 * Utility class containing various operations on types.
53 *
54 * <p>Unless other names are more illustrative, the following naming
55 * conventions should be observed in this file:
56 *
57 * <dl>
58 * <dt>t</dt>
59 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
60 * <dt>s</dt>
61 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
62 * <dt>ts</dt>
63 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
64 * <dt>ss</dt>
65 * <dd>A second list of types should be named ss.</dd>
66 * </dl>
67 *
68 * <p><b>This is NOT part of any supported API.
69 * If you write code that depends on this, you do so at your own risk.
70 * This code and its internal interfaces are subject to change or
71 * deletion without notice.</b>
72 */
73 public class Types {
74 protected static final Context.Key<Types> typesKey =
75 new Context.Key<Types>();
76
77 final Symtab syms;
78 final JavacMessages messages;
79 final Names names;
80 final boolean allowBoxing;
81 final boolean allowCovariantReturns;
82 final boolean allowObjectToPrimitiveCast;
83 final boolean allowDefaultMethods;
84 final ClassReader reader;
85 final Check chk;
86 JCDiagnostic.Factory diags;
87 List<Warner> warnStack = List.nil();
88 final Name capturedName;
89 private final FunctionDescriptorLookupError functionDescriptorLookupError;
90
91 public final Warner noWarnings;
92
93 // <editor-fold defaultstate="collapsed" desc="Instantiating">
94 public static Types instance(Context context) {
95 Types instance = context.get(typesKey);
96 if (instance == null)
97 instance = new Types(context);
98 return instance;
99 }
100
101 protected Types(Context context) {
102 context.put(typesKey, this);
103 syms = Symtab.instance(context);
104 names = Names.instance(context);
105 Source source = Source.instance(context);
106 allowBoxing = source.allowBoxing();
107 allowCovariantReturns = source.allowCovariantReturns();
108 allowObjectToPrimitiveCast = source.allowObjectToPrimitiveCast();
109 allowDefaultMethods = source.allowDefaultMethods();
110 reader = ClassReader.instance(context);
111 chk = Check.instance(context);
112 capturedName = names.fromString("<captured wildcard>");
113 messages = JavacMessages.instance(context);
114 diags = JCDiagnostic.Factory.instance(context);
115 functionDescriptorLookupError = new FunctionDescriptorLookupError();
116 noWarnings = new Warner(null);
117 }
118 // </editor-fold>
119
120 // <editor-fold defaultstate="collapsed" desc="upperBound">
121 /**
122 * The "rvalue conversion".<br>
123 * The upper bound of most types is the type
124 * itself. Wildcards, on the other hand have upper
125 * and lower bounds.
126 * @param t a type
127 * @return the upper bound of the given type
128 */
129 public Type upperBound(Type t) {
130 return upperBound.visit(t);
131 }
132 // where
133 private final MapVisitor<Void> upperBound = new MapVisitor<Void>() {
134
135 @Override
136 public Type visitWildcardType(WildcardType t, Void ignored) {
137 if (t.isSuperBound())
138 return t.bound == null ? syms.objectType : t.bound.bound;
139 else
140 return visit(t.type);
141 }
142
143 @Override
144 public Type visitCapturedType(CapturedType t, Void ignored) {
145 return visit(t.bound);
146 }
147 };
148 // </editor-fold>
149
150 // <editor-fold defaultstate="collapsed" desc="lowerBound">
151 /**
152 * The "lvalue conversion".<br>
153 * The lower bound of most types is the type
154 * itself. Wildcards, on the other hand have upper
155 * and lower bounds.
156 * @param t a type
157 * @return the lower bound of the given type
158 */
159 public Type lowerBound(Type t) {
160 return lowerBound.visit(t);
161 }
162 // where
163 private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() {
164
165 @Override
166 public Type visitWildcardType(WildcardType t, Void ignored) {
167 return t.isExtendsBound() ? syms.botType : visit(t.type);
168 }
169
170 @Override
171 public Type visitCapturedType(CapturedType t, Void ignored) {
172 return visit(t.getLowerBound());
173 }
174 };
175 // </editor-fold>
176
177 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
178 /**
179 * Checks that all the arguments to a class are unbounded
180 * wildcards or something else that doesn't make any restrictions
181 * on the arguments. If a class isUnbounded, a raw super- or
182 * subclass can be cast to it without a warning.
183 * @param t a type
184 * @return true iff the given type is unbounded or raw
185 */
186 public boolean isUnbounded(Type t) {
187 return isUnbounded.visit(t);
188 }
189 // where
190 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
191
192 public Boolean visitType(Type t, Void ignored) {
193 return true;
194 }
195
196 @Override
197 public Boolean visitClassType(ClassType t, Void ignored) {
198 List<Type> parms = t.tsym.type.allparams();
199 List<Type> args = t.allparams();
200 while (parms.nonEmpty()) {
201 WildcardType unb = new WildcardType(syms.objectType,
202 BoundKind.UNBOUND,
203 syms.boundClass,
204 (TypeVar)parms.head.unannotatedType());
205 if (!containsType(args.head, unb))
206 return false;
207 parms = parms.tail;
208 args = args.tail;
209 }
210 return true;
211 }
212 };
213 // </editor-fold>
214
215 // <editor-fold defaultstate="collapsed" desc="asSub">
216 /**
217 * Return the least specific subtype of t that starts with symbol
218 * sym. If none exists, return null. The least specific subtype
219 * is determined as follows:
220 *
221 * <p>If there is exactly one parameterized instance of sym that is a
222 * subtype of t, that parameterized instance is returned.<br>
223 * Otherwise, if the plain type or raw type `sym' is a subtype of
224 * type t, the type `sym' itself is returned. Otherwise, null is
225 * returned.
226 */
227 public Type asSub(Type t, Symbol sym) {
228 return asSub.visit(t, sym);
229 }
230 // where
231 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
232
233 public Type visitType(Type t, Symbol sym) {
234 return null;
235 }
236
237 @Override
238 public Type visitClassType(ClassType t, Symbol sym) {
239 if (t.tsym == sym)
240 return t;
241 Type base = asSuper(sym.type, t.tsym);
242 if (base == null)
243 return null;
244 ListBuffer<Type> from = new ListBuffer<Type>();
245 ListBuffer<Type> to = new ListBuffer<Type>();
246 try {
247 adapt(base, t, from, to);
248 } catch (AdaptFailure ex) {
249 return null;
250 }
251 Type res = subst(sym.type, from.toList(), to.toList());
252 if (!isSubtype(res, t))
253 return null;
254 ListBuffer<Type> openVars = new ListBuffer<Type>();
255 for (List<Type> l = sym.type.allparams();
256 l.nonEmpty(); l = l.tail)
257 if (res.contains(l.head) && !t.contains(l.head))
258 openVars.append(l.head);
259 if (openVars.nonEmpty()) {
260 if (t.isRaw()) {
261 // The subtype of a raw type is raw
262 res = erasure(res);
263 } else {
264 // Unbound type arguments default to ?
265 List<Type> opens = openVars.toList();
266 ListBuffer<Type> qs = new ListBuffer<Type>();
267 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
268 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head.unannotatedType()));
269 }
270 res = subst(res, opens, qs.toList());
271 }
272 }
273 return res;
274 }
275
276 @Override
277 public Type visitErrorType(ErrorType t, Symbol sym) {
278 return t;
279 }
280 };
281 // </editor-fold>
282
283 // <editor-fold defaultstate="collapsed" desc="isConvertible">
284 /**
285 * Is t a subtype of or convertible via boxing/unboxing
286 * conversion to s?
287 */
288 public boolean isConvertible(Type t, Type s, Warner warn) {
289 if (t.tag == ERROR)
290 return true;
291 boolean tPrimitive = t.isPrimitive();
292 boolean sPrimitive = s.isPrimitive();
293 if (tPrimitive == sPrimitive) {
294 return isSubtypeUnchecked(t, s, warn);
295 }
296 if (!allowBoxing) return false;
297 return tPrimitive
298 ? isSubtype(boxedClass(t).type, s)
299 : isSubtype(unboxedType(t), s);
300 }
301
302 /**
303 * Is t a subtype of or convertiable via boxing/unboxing
304 * convertions to s?
305 */
306 public boolean isConvertible(Type t, Type s) {
307 return isConvertible(t, s, noWarnings);
308 }
309 // </editor-fold>
310
311 // <editor-fold defaultstate="collapsed" desc="findSam">
312
313 /**
314 * Exception used to report a function descriptor lookup failure. The exception
315 * wraps a diagnostic that can be used to generate more details error
316 * messages.
317 */
318 public static class FunctionDescriptorLookupError extends RuntimeException {
319 private static final long serialVersionUID = 0;
320
321 JCDiagnostic diagnostic;
322
323 FunctionDescriptorLookupError() {
324 this.diagnostic = null;
325 }
326
327 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
328 this.diagnostic = diag;
329 return this;
330 }
331
332 public JCDiagnostic getDiagnostic() {
333 return diagnostic;
334 }
335 }
336
337 /**
338 * A cache that keeps track of function descriptors associated with given
339 * functional interfaces.
340 */
341 class DescriptorCache {
342
343 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<TypeSymbol, Entry>();
344
345 class FunctionDescriptor {
346 Symbol descSym;
347
348 FunctionDescriptor(Symbol descSym) {
349 this.descSym = descSym;
350 }
351
352 public Symbol getSymbol() {
353 return descSym;
354 }
355
356 public Type getType(Type site) {
357 site = removeWildcards(site);
358 if (!chk.checkValidGenericType(site)) {
359 //if the inferred functional interface type is not well-formed,
360 //or if it's not a subtype of the original target, issue an error
361 throw failure(diags.fragment("no.suitable.functional.intf.inst", site));
362 }
363 return memberType(site, descSym);
364 }
365 }
366
367 class Entry {
368 final FunctionDescriptor cachedDescRes;
369 final int prevMark;
370
371 public Entry(FunctionDescriptor cachedDescRes,
372 int prevMark) {
373 this.cachedDescRes = cachedDescRes;
374 this.prevMark = prevMark;
375 }
376
377 boolean matches(int mark) {
378 return this.prevMark == mark;
379 }
380 }
381
382 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
383 Entry e = _map.get(origin);
384 CompoundScope members = membersClosure(origin.type, false);
385 if (e == null ||
386 !e.matches(members.getMark())) {
387 FunctionDescriptor descRes = findDescriptorInternal(origin, members);
388 _map.put(origin, new Entry(descRes, members.getMark()));
389 return descRes;
390 }
391 else {
392 return e.cachedDescRes;
393 }
394 }
395
396 /**
397 * Compute the function descriptor associated with a given functional interface
398 */
399 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin, CompoundScope membersCache) throws FunctionDescriptorLookupError {
400 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0) {
401 //t must be an interface
402 throw failure("not.a.functional.intf", origin);
403 }
404
405 final ListBuffer<Symbol> abstracts = ListBuffer.lb();
406 for (Symbol sym : membersCache.getElements(new DescriptorFilter(origin))) {
407 Type mtype = memberType(origin.type, sym);
408 if (abstracts.isEmpty() ||
409 (sym.name == abstracts.first().name &&
410 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
411 abstracts.append(sym);
412 } else {
413 //the target method(s) should be the only abstract members of t
414 throw failure("not.a.functional.intf.1", origin,
415 diags.fragment("incompatible.abstracts", Kinds.kindName(origin), origin));
416 }
417 }
418 if (abstracts.isEmpty()) {
419 //t must define a suitable non-generic method
420 throw failure("not.a.functional.intf.1", origin,
421 diags.fragment("no.abstracts", Kinds.kindName(origin), origin));
422 } else if (abstracts.size() == 1) {
423 return new FunctionDescriptor(abstracts.first());
424 } else { // size > 1
425 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
426 if (descRes == null) {
427 //we can get here if the functional interface is ill-formed
428 ListBuffer<JCDiagnostic> descriptors = ListBuffer.lb();
429 for (Symbol desc : abstracts) {
430 String key = desc.type.getThrownTypes().nonEmpty() ?
431 "descriptor.throws" : "descriptor";
432 descriptors.append(diags.fragment(key, desc.name,
433 desc.type.getParameterTypes(),
434 desc.type.getReturnType(),
435 desc.type.getThrownTypes()));
436 }
437 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
438 new JCDiagnostic.MultilineDiagnostic(diags.fragment("incompatible.descs.in.functional.intf",
439 Kinds.kindName(origin), origin), descriptors.toList());
440 throw failure(incompatibleDescriptors);
441 }
442 return descRes;
443 }
444 }
445
446 /**
447 * Compute a synthetic type for the target descriptor given a list
448 * of override-equivalent methods in the functional interface type.
449 * The resulting method type is a method type that is override-equivalent
450 * and return-type substitutable with each method in the original list.
451 */
452 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
453 //pick argument types - simply take the signature that is a
454 //subsignature of all other signatures in the list (as per JLS 8.4.2)
455 List<Symbol> mostSpecific = List.nil();
456 outer: for (Symbol msym1 : methodSyms) {
457 Type mt1 = memberType(origin.type, msym1);
458 for (Symbol msym2 : methodSyms) {
459 Type mt2 = memberType(origin.type, msym2);
460 if (!isSubSignature(mt1, mt2)) {
461 continue outer;
462 }
463 }
464 mostSpecific = mostSpecific.prepend(msym1);
465 }
466 if (mostSpecific.isEmpty()) {
467 return null;
468 }
469
470
471 //pick return types - this is done in two phases: (i) first, the most
472 //specific return type is chosen using strict subtyping; if this fails,
473 //a second attempt is made using return type substitutability (see JLS 8.4.5)
474 boolean phase2 = false;
475 Symbol bestSoFar = null;
476 while (bestSoFar == null) {
477 outer: for (Symbol msym1 : mostSpecific) {
478 Type mt1 = memberType(origin.type, msym1);
479 for (Symbol msym2 : methodSyms) {
480 Type mt2 = memberType(origin.type, msym2);
481 if (phase2 ?
482 !returnTypeSubstitutable(mt1, mt2) :
483 !isSubtypeInternal(mt1.getReturnType(), mt2.getReturnType())) {
484 continue outer;
485 }
486 }
487 bestSoFar = msym1;
488 }
489 if (phase2) {
490 break;
491 } else {
492 phase2 = true;
493 }
494 }
495 if (bestSoFar == null) return null;
496
497 //merge thrown types - form the intersection of all the thrown types in
498 //all the signatures in the list
499 List<Type> thrown = null;
500 for (Symbol msym1 : methodSyms) {
501 Type mt1 = memberType(origin.type, msym1);
502 thrown = (thrown == null) ?
503 mt1.getThrownTypes() :
504 chk.intersect(mt1.getThrownTypes(), thrown);
505 }
506
507 final List<Type> thrown1 = thrown;
508 return new FunctionDescriptor(bestSoFar) {
509 @Override
510 public Type getType(Type origin) {
511 Type mt = memberType(origin, getSymbol());
512 return createMethodTypeWithThrown(mt, thrown1);
513 }
514 };
515 }
516
517 boolean isSubtypeInternal(Type s, Type t) {
518 return (s.isPrimitive() && t.isPrimitive()) ?
519 isSameType(t, s) :
520 isSubtype(s, t);
521 }
522
523 FunctionDescriptorLookupError failure(String msg, Object... args) {
524 return failure(diags.fragment(msg, args));
525 }
526
527 FunctionDescriptorLookupError failure(JCDiagnostic diag) {
528 return functionDescriptorLookupError.setMessage(diag);
529 }
530 }
531
532 private DescriptorCache descCache = new DescriptorCache();
533
534 /**
535 * Find the method descriptor associated to this class symbol - if the
536 * symbol 'origin' is not a functional interface, an exception is thrown.
537 */
538 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
539 return descCache.get(origin).getSymbol();
540 }
541
542 /**
543 * Find the type of the method descriptor associated to this class symbol -
544 * if the symbol 'origin' is not a functional interface, an exception is thrown.
545 */
546 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
547 return descCache.get(origin.tsym).getType(origin);
548 }
549
550 /**
551 * Is given type a functional interface?
552 */
553 public boolean isFunctionalInterface(TypeSymbol tsym) {
554 try {
555 findDescriptorSymbol(tsym);
556 return true;
557 } catch (FunctionDescriptorLookupError ex) {
558 return false;
559 }
560 }
561
562 public boolean isFunctionalInterface(Type site) {
563 try {
564 findDescriptorType(site);
565 return true;
566 } catch (FunctionDescriptorLookupError ex) {
567 return false;
568 }
569 }
570
571 public Type removeWildcards(Type site) {
572 Type capturedSite = capture(site);
573 if (capturedSite != site) {
574 Type formalInterface = site.tsym.type;
575 ListBuffer<Type> typeargs = ListBuffer.lb();
576 List<Type> actualTypeargs = site.getTypeArguments();
577 List<Type> capturedTypeargs = capturedSite.getTypeArguments();
578 //simply replace the wildcards with its bound
579 for (Type t : formalInterface.getTypeArguments()) {
580 if (actualTypeargs.head.hasTag(WILDCARD)) {
581 WildcardType wt = (WildcardType)actualTypeargs.head.unannotatedType();
582 Type bound;
583 switch (wt.kind) {
584 case EXTENDS:
585 case UNBOUND:
586 CapturedType capVar = (CapturedType)capturedTypeargs.head.unannotatedType();
587 //use declared bound if it doesn't depend on formal type-args
588 bound = capVar.bound.containsAny(capturedSite.getTypeArguments()) ?
589 wt.type : capVar.bound;
590 break;
591 default:
592 bound = wt.type;
593 }
594 typeargs.append(bound);
595 } else {
596 typeargs.append(actualTypeargs.head);
597 }
598 actualTypeargs = actualTypeargs.tail;
599 capturedTypeargs = capturedTypeargs.tail;
600 }
601 return subst(formalInterface, formalInterface.getTypeArguments(), typeargs.toList());
602 } else {
603 return site;
604 }
605 }
606 // </editor-fold>
607
608 /**
609 * Scope filter used to skip methods that should be ignored (such as methods
610 * overridden by j.l.Object) during function interface conversion interface check
611 */
612 class DescriptorFilter implements Filter<Symbol> {
613
614 TypeSymbol origin;
615
616 DescriptorFilter(TypeSymbol origin) {
617 this.origin = origin;
618 }
619
620 @Override
621 public boolean accepts(Symbol sym) {
622 return sym.kind == Kinds.MTH &&
623 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
624 !overridesObjectMethod(origin, sym) &&
625 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
626 }
627 };
628
629 // <editor-fold defaultstate="collapsed" desc="isSubtype">
630 /**
631 * Is t an unchecked subtype of s?
632 */
633 public boolean isSubtypeUnchecked(Type t, Type s) {
634 return isSubtypeUnchecked(t, s, noWarnings);
635 }
636 /**
637 * Is t an unchecked subtype of s?
638 */
639 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
640 boolean result = isSubtypeUncheckedInternal(t, s, warn);
641 if (result) {
642 checkUnsafeVarargsConversion(t, s, warn);
643 }
644 return result;
645 }
646 //where
647 private boolean isSubtypeUncheckedInternal(Type t, Type s, Warner warn) {
648 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
649 t = t.unannotatedType();
650 s = s.unannotatedType();
651 if (((ArrayType)t).elemtype.isPrimitive()) {
652 return isSameType(elemtype(t), elemtype(s));
653 } else {
654 return isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
655 }
656 } else if (isSubtype(t, s)) {
657 return true;
658 }
659 else if (t.tag == TYPEVAR) {
660 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
661 }
662 else if (!s.isRaw()) {
663 Type t2 = asSuper(t, s.tsym);
664 if (t2 != null && t2.isRaw()) {
665 if (isReifiable(s))
666 warn.silentWarn(LintCategory.UNCHECKED);
667 else
668 warn.warn(LintCategory.UNCHECKED);
669 return true;
670 }
671 }
672 return false;
673 }
674
675 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
676 if (t.tag != ARRAY || isReifiable(t))
677 return;
678 t = t.unannotatedType();
679 s = s.unannotatedType();
680 ArrayType from = (ArrayType)t;
681 boolean shouldWarn = false;
682 switch (s.tag) {
683 case ARRAY:
684 ArrayType to = (ArrayType)s;
685 shouldWarn = from.isVarargs() &&
686 !to.isVarargs() &&
687 !isReifiable(from);
688 break;
689 case CLASS:
690 shouldWarn = from.isVarargs();
691 break;
692 }
693 if (shouldWarn) {
694 warn.warn(LintCategory.VARARGS);
695 }
696 }
697
698 /**
699 * Is t a subtype of s?<br>
700 * (not defined for Method and ForAll types)
701 */
702 final public boolean isSubtype(Type t, Type s) {
703 return isSubtype(t, s, true);
704 }
705 final public boolean isSubtypeNoCapture(Type t, Type s) {
706 return isSubtype(t, s, false);
707 }
708 public boolean isSubtype(Type t, Type s, boolean capture) {
709 if (t == s)
710 return true;
711
712 t = t.unannotatedType();
713 s = s.unannotatedType();
714
715 if (t == s)
716 return true;
717
718 if (s.isPartial())
719 return isSuperType(s, t);
720
721 if (s.isCompound()) {
722 for (Type s2 : interfaces(s).prepend(supertype(s))) {
723 if (!isSubtype(t, s2, capture))
724 return false;
725 }
726 return true;
727 }
728
729 Type lower = lowerBound(s);
730 if (s != lower)
731 return isSubtype(capture ? capture(t) : t, lower, false);
732
733 return isSubtype.visit(capture ? capture(t) : t, s);
734 }
735 // where
736 private TypeRelation isSubtype = new TypeRelation()
737 {
738 public Boolean visitType(Type t, Type s) {
739 switch (t.tag) {
740 case BYTE:
741 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
742 case CHAR:
743 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
744 case SHORT: case INT: case LONG:
745 case FLOAT: case DOUBLE:
746 return t.getTag().isSubRangeOf(s.getTag());
747 case BOOLEAN: case VOID:
748 return t.hasTag(s.getTag());
749 case TYPEVAR:
750 return isSubtypeNoCapture(t.getUpperBound(), s);
751 case BOT:
752 return
753 s.hasTag(BOT) || s.hasTag(CLASS) ||
754 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
755 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
756 case NONE:
757 return false;
758 default:
759 throw new AssertionError("isSubtype " + t.tag);
760 }
761 }
762
763 private Set<TypePair> cache = new HashSet<TypePair>();
764
765 private boolean containsTypeRecursive(Type t, Type s) {
766 TypePair pair = new TypePair(t, s);
767 if (cache.add(pair)) {
768 try {
769 return containsType(t.getTypeArguments(),
770 s.getTypeArguments());
771 } finally {
772 cache.remove(pair);
773 }
774 } else {
775 return containsType(t.getTypeArguments(),
776 rewriteSupers(s).getTypeArguments());
777 }
778 }
779
780 private Type rewriteSupers(Type t) {
781 if (!t.isParameterized())
782 return t;
783 ListBuffer<Type> from = lb();
784 ListBuffer<Type> to = lb();
785 adaptSelf(t, from, to);
786 if (from.isEmpty())
787 return t;
788 ListBuffer<Type> rewrite = lb();
789 boolean changed = false;
790 for (Type orig : to.toList()) {
791 Type s = rewriteSupers(orig);
792 if (s.isSuperBound() && !s.isExtendsBound()) {
793 s = new WildcardType(syms.objectType,
794 BoundKind.UNBOUND,
795 syms.boundClass);
796 changed = true;
797 } else if (s != orig) {
798 s = new WildcardType(upperBound(s),
799 BoundKind.EXTENDS,
800 syms.boundClass);
801 changed = true;
802 }
803 rewrite.append(s);
804 }
805 if (changed)
806 return subst(t.tsym.type, from.toList(), rewrite.toList());
807 else
808 return t;
809 }
810
811 @Override
812 public Boolean visitClassType(ClassType t, Type s) {
813 Type sup = asSuper(t, s.tsym);
814 return sup != null
815 && sup.tsym == s.tsym
816 // You're not allowed to write
817 // Vector<Object> vec = new Vector<String>();
818 // But with wildcards you can write
819 // Vector<? extends Object> vec = new Vector<String>();
820 // which means that subtype checking must be done
821 // here instead of same-type checking (via containsType).
822 && (!s.isParameterized() || containsTypeRecursive(s, sup))
823 && isSubtypeNoCapture(sup.getEnclosingType(),
824 s.getEnclosingType());
825 }
826
827 @Override
828 public Boolean visitArrayType(ArrayType t, Type s) {
829 if (s.tag == ARRAY) {
830 if (t.elemtype.isPrimitive())
831 return isSameType(t.elemtype, elemtype(s));
832 else
833 return isSubtypeNoCapture(t.elemtype, elemtype(s));
834 }
835
836 if (s.tag == CLASS) {
837 Name sname = s.tsym.getQualifiedName();
838 return sname == names.java_lang_Object
839 || sname == names.java_lang_Cloneable
840 || sname == names.java_io_Serializable;
841 }
842
843 return false;
844 }
845
846 @Override
847 public Boolean visitUndetVar(UndetVar t, Type s) {
848 //todo: test against origin needed? or replace with substitution?
849 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN) {
850 return true;
851 } else if (s.tag == BOT) {
852 //if 's' is 'null' there's no instantiated type U for which
853 //U <: s (but 'null' itself, which is not a valid type)
854 return false;
855 }
856
857 t.addBound(InferenceBound.UPPER, s, Types.this);
858 return true;
859 }
860
861 @Override
862 public Boolean visitErrorType(ErrorType t, Type s) {
863 return true;
864 }
865 };
866
867 /**
868 * Is t a subtype of every type in given list `ts'?<br>
869 * (not defined for Method and ForAll types)<br>
870 * Allows unchecked conversions.
871 */
872 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
873 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
874 if (!isSubtypeUnchecked(t, l.head, warn))
875 return false;
876 return true;
877 }
878
879 /**
880 * Are corresponding elements of ts subtypes of ss? If lists are
881 * of different length, return false.
882 */
883 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
884 while (ts.tail != null && ss.tail != null
885 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
886 isSubtype(ts.head, ss.head)) {
887 ts = ts.tail;
888 ss = ss.tail;
889 }
890 return ts.tail == null && ss.tail == null;
891 /*inlined: ts.isEmpty() && ss.isEmpty();*/
892 }
893
894 /**
895 * Are corresponding elements of ts subtypes of ss, allowing
896 * unchecked conversions? If lists are of different length,
897 * return false.
898 **/
899 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
900 while (ts.tail != null && ss.tail != null
901 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
902 isSubtypeUnchecked(ts.head, ss.head, warn)) {
903 ts = ts.tail;
904 ss = ss.tail;
905 }
906 return ts.tail == null && ss.tail == null;
907 /*inlined: ts.isEmpty() && ss.isEmpty();*/
908 }
909 // </editor-fold>
910
911 // <editor-fold defaultstate="collapsed" desc="isSuperType">
912 /**
913 * Is t a supertype of s?
914 */
915 public boolean isSuperType(Type t, Type s) {
916 switch (t.tag) {
917 case ERROR:
918 return true;
919 case UNDETVAR: {
920 UndetVar undet = (UndetVar)t;
921 if (t == s ||
922 undet.qtype == s ||
923 s.tag == ERROR ||
924 s.tag == BOT) return true;
925 undet.addBound(InferenceBound.LOWER, s, this);
926 return true;
927 }
928 default:
929 return isSubtype(s, t);
930 }
931 }
932 // </editor-fold>
933
934 // <editor-fold defaultstate="collapsed" desc="isSameType">
935 /**
936 * Are corresponding elements of the lists the same type? If
937 * lists are of different length, return false.
938 */
939 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
940 return isSameTypes(ts, ss, false);
941 }
942 public boolean isSameTypes(List<Type> ts, List<Type> ss, boolean strict) {
943 while (ts.tail != null && ss.tail != null
944 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
945 isSameType(ts.head, ss.head, strict)) {
946 ts = ts.tail;
947 ss = ss.tail;
948 }
949 return ts.tail == null && ss.tail == null;
950 /*inlined: ts.isEmpty() && ss.isEmpty();*/
951 }
952
953 /**
954 * Is t the same type as s?
955 */
956 public boolean isSameType(Type t, Type s) {
957 return isSameType(t, s, false);
958 }
959 public boolean isSameType(Type t, Type s, boolean strict) {
960 return strict ?
961 isSameTypeStrict.visit(t, s) :
962 isSameTypeLoose.visit(t, s);
963 }
964 public boolean isSameAnnotatedType(Type t, Type s) {
965 return isSameAnnotatedType.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.unannotatedType(), (TypeVar)s.unannotatedType());
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 LooseSameTypeVisitor();
1100
1101 private class LooseSameTypeVisitor extends SameTypeVisitor {
1102 @Override
1103 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
1104 return tv1.tsym == tv2.tsym && visit(tv1.getUpperBound(), tv2.getUpperBound());
1105 }
1106 @Override
1107 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
1108 return containsTypeEquivalent(ts1, ts2);
1109 }
1110 };
1111
1112 /**
1113 * Strict type-equality relation - type variables are considered
1114 * equals if they share the same object identity.
1115 */
1116 TypeRelation isSameTypeStrict = new SameTypeVisitor() {
1117 @Override
1118 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
1119 return tv1 == tv2;
1120 }
1121 @Override
1122 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
1123 return isSameTypes(ts1, ts2, true);
1124 }
1125
1126 @Override
1127 public Boolean visitWildcardType(WildcardType t, Type s) {
1128 if (!s.hasTag(WILDCARD)) {
1129 return false;
1130 } else {
1131 WildcardType t2 = (WildcardType)s.unannotatedType();
1132 return t.kind == t2.kind &&
1133 isSameType(t.type, t2.type, true);
1134 }
1135 }
1136 };
1137
1138 /**
1139 * A version of LooseSameTypeVisitor that takes AnnotatedTypes
1140 * into account.
1141 */
1142 TypeRelation isSameAnnotatedType = new LooseSameTypeVisitor() {
1143 @Override
1144 public Boolean visitAnnotatedType(AnnotatedType t, Type s) {
1145 if (!s.isAnnotated())
1146 return false;
1147 if (!t.getAnnotationMirrors().containsAll(s.getAnnotationMirrors()))
1148 return false;
1149 if (!s.getAnnotationMirrors().containsAll(t.getAnnotationMirrors()))
1150 return false;
1151 return visit(t.underlyingType, s);
1152 }
1153 };
1154 // </editor-fold>
1155
1156 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1157 public boolean containedBy(Type t, Type s) {
1158 switch (t.tag) {
1159 case UNDETVAR:
1160 if (s.tag == WILDCARD) {
1161 UndetVar undetvar = (UndetVar)t;
1162 WildcardType wt = (WildcardType)s.unannotatedType();
1163 switch(wt.kind) {
1164 case UNBOUND: //similar to ? extends Object
1165 case EXTENDS: {
1166 Type bound = upperBound(s);
1167 undetvar.addBound(InferenceBound.UPPER, bound, this);
1168 break;
1169 }
1170 case SUPER: {
1171 Type bound = lowerBound(s);
1172 undetvar.addBound(InferenceBound.LOWER, bound, this);
1173 break;
1174 }
1175 }
1176 return true;
1177 } else {
1178 return isSameType(t, s);
1179 }
1180 case ERROR:
1181 return true;
1182 default:
1183 return containsType(s, t);
1184 }
1185 }
1186
1187 boolean containsType(List<Type> ts, List<Type> ss) {
1188 while (ts.nonEmpty() && ss.nonEmpty()
1189 && containsType(ts.head, ss.head)) {
1190 ts = ts.tail;
1191 ss = ss.tail;
1192 }
1193 return ts.isEmpty() && ss.isEmpty();
1194 }
1195
1196 /**
1197 * Check if t contains s.
1198 *
1199 * <p>T contains S if:
1200 *
1201 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1202 *
1203 * <p>This relation is only used by ClassType.isSubtype(), that
1204 * is,
1205 *
1206 * <p>{@code C<S> <: C<T> if T contains S.}
1207 *
1208 * <p>Because of F-bounds, this relation can lead to infinite
1209 * recursion. Thus we must somehow break that recursion. Notice
1210 * that containsType() is only called from ClassType.isSubtype().
1211 * Since the arguments have already been checked against their
1212 * bounds, we know:
1213 *
1214 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1215 *
1216 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1217 *
1218 * @param t a type
1219 * @param s a type
1220 */
1221 public boolean containsType(Type t, Type s) {
1222 return containsType.visit(t, s);
1223 }
1224 // where
1225 private TypeRelation containsType = new TypeRelation() {
1226
1227 private Type U(Type t) {
1228 while (t.tag == WILDCARD) {
1229 WildcardType w = (WildcardType)t.unannotatedType();
1230 if (w.isSuperBound())
1231 return w.bound == null ? syms.objectType : w.bound.bound;
1232 else
1233 t = w.type;
1234 }
1235 return t;
1236 }
1237
1238 private Type L(Type t) {
1239 while (t.tag == WILDCARD) {
1240 WildcardType w = (WildcardType)t.unannotatedType();
1241 if (w.isExtendsBound())
1242 return syms.botType;
1243 else
1244 t = w.type;
1245 }
1246 return t;
1247 }
1248
1249 public Boolean visitType(Type t, Type s) {
1250 if (s.isPartial())
1251 return containedBy(s, t);
1252 else
1253 return isSameType(t, s);
1254 }
1255
1256 // void debugContainsType(WildcardType t, Type s) {
1257 // System.err.println();
1258 // System.err.format(" does %s contain %s?%n", t, s);
1259 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1260 // upperBound(s), s, t, U(t),
1261 // t.isSuperBound()
1262 // || isSubtypeNoCapture(upperBound(s), U(t)));
1263 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1264 // L(t), t, s, lowerBound(s),
1265 // t.isExtendsBound()
1266 // || isSubtypeNoCapture(L(t), lowerBound(s)));
1267 // System.err.println();
1268 // }
1269
1270 @Override
1271 public Boolean visitWildcardType(WildcardType t, Type s) {
1272 if (s.isPartial())
1273 return containedBy(s, t);
1274 else {
1275 // debugContainsType(t, s);
1276 return isSameWildcard(t, s)
1277 || isCaptureOf(s, t)
1278 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
1279 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
1280 }
1281 }
1282
1283 @Override
1284 public Boolean visitUndetVar(UndetVar t, Type s) {
1285 if (s.tag != WILDCARD)
1286 return isSameType(t, s);
1287 else
1288 return false;
1289 }
1290
1291 @Override
1292 public Boolean visitErrorType(ErrorType t, Type s) {
1293 return true;
1294 }
1295 };
1296
1297 public boolean isCaptureOf(Type s, WildcardType t) {
1298 if (s.tag != TYPEVAR || !((TypeVar)s.unannotatedType()).isCaptured())
1299 return false;
1300 return isSameWildcard(t, ((CapturedType)s.unannotatedType()).wildcard);
1301 }
1302
1303 public boolean isSameWildcard(WildcardType t, Type s) {
1304 if (s.tag != WILDCARD)
1305 return false;
1306 WildcardType w = (WildcardType)s.unannotatedType();
1307 return w.kind == t.kind && w.type == t.type;
1308 }
1309
1310 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1311 while (ts.nonEmpty() && ss.nonEmpty()
1312 && containsTypeEquivalent(ts.head, ss.head)) {
1313 ts = ts.tail;
1314 ss = ss.tail;
1315 }
1316 return ts.isEmpty() && ss.isEmpty();
1317 }
1318 // </editor-fold>
1319
1320 /**
1321 * Can t and s be compared for equality? Any primitive ==
1322 * primitive or primitive == object comparisons here are an error.
1323 * Unboxing and correct primitive == primitive comparisons are
1324 * already dealt with in Attr.visitBinary.
1325 *
1326 */
1327 public boolean isEqualityComparable(Type s, Type t, Warner warn) {
1328 if (t.isNumeric() && s.isNumeric())
1329 return true;
1330
1331 boolean tPrimitive = t.isPrimitive();
1332 boolean sPrimitive = s.isPrimitive();
1333 if (!tPrimitive && !sPrimitive) {
1334 return isCastable(s, t, warn) || isCastable(t, s, warn);
1335 } else {
1336 return false;
1337 }
1338 }
1339
1340 // <editor-fold defaultstate="collapsed" desc="isCastable">
1341 public boolean isCastable(Type t, Type s) {
1342 return isCastable(t, s, noWarnings);
1343 }
1344
1345 /**
1346 * Is t is castable to s?<br>
1347 * s is assumed to be an erased type.<br>
1348 * (not defined for Method and ForAll types).
1349 */
1350 public boolean isCastable(Type t, Type s, Warner warn) {
1351 if (t == s)
1352 return true;
1353
1354 if (t.isPrimitive() != s.isPrimitive())
1355 return allowBoxing && (
1356 isConvertible(t, s, warn)
1357 || (allowObjectToPrimitiveCast &&
1358 s.isPrimitive() &&
1359 isSubtype(boxedClass(s).type, t)));
1360 if (warn != warnStack.head) {
1361 try {
1362 warnStack = warnStack.prepend(warn);
1363 checkUnsafeVarargsConversion(t, s, warn);
1364 return isCastable.visit(t,s);
1365 } finally {
1366 warnStack = warnStack.tail;
1367 }
1368 } else {
1369 return isCastable.visit(t,s);
1370 }
1371 }
1372 // where
1373 private TypeRelation isCastable = new TypeRelation() {
1374
1375 public Boolean visitType(Type t, Type s) {
1376 if (s.tag == ERROR)
1377 return true;
1378
1379 switch (t.tag) {
1380 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1381 case DOUBLE:
1382 return s.isNumeric();
1383 case BOOLEAN:
1384 return s.tag == BOOLEAN;
1385 case VOID:
1386 return false;
1387 case BOT:
1388 return isSubtype(t, s);
1389 default:
1390 throw new AssertionError();
1391 }
1392 }
1393
1394 @Override
1395 public Boolean visitWildcardType(WildcardType t, Type s) {
1396 return isCastable(upperBound(t), s, warnStack.head);
1397 }
1398
1399 @Override
1400 public Boolean visitClassType(ClassType t, Type s) {
1401 if (s.tag == ERROR || s.tag == BOT)
1402 return true;
1403
1404 if (s.tag == TYPEVAR) {
1405 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1406 warnStack.head.warn(LintCategory.UNCHECKED);
1407 return true;
1408 } else {
1409 return false;
1410 }
1411 }
1412
1413 if (t.isCompound() || s.isCompound()) {
1414 return !t.isCompound() ?
1415 visitIntersectionType((IntersectionClassType)s.unannotatedType(), t, true) :
1416 visitIntersectionType((IntersectionClassType)t.unannotatedType(), s, false);
1417 }
1418
1419 if (s.tag == CLASS || s.tag == ARRAY) {
1420 boolean upcast;
1421 if ((upcast = isSubtype(erasure(t), erasure(s)))
1422 || isSubtype(erasure(s), erasure(t))) {
1423 if (!upcast && s.tag == ARRAY) {
1424 if (!isReifiable(s))
1425 warnStack.head.warn(LintCategory.UNCHECKED);
1426 return true;
1427 } else if (s.isRaw()) {
1428 return true;
1429 } else if (t.isRaw()) {
1430 if (!isUnbounded(s))
1431 warnStack.head.warn(LintCategory.UNCHECKED);
1432 return true;
1433 }
1434 // Assume |a| <: |b|
1435 final Type a = upcast ? t : s;
1436 final Type b = upcast ? s : t;
1437 final boolean HIGH = true;
1438 final boolean LOW = false;
1439 final boolean DONT_REWRITE_TYPEVARS = false;
1440 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1441 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1442 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1443 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1444 Type lowSub = asSub(bLow, aLow.tsym);
1445 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1446 if (highSub == null) {
1447 final boolean REWRITE_TYPEVARS = true;
1448 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1449 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1450 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1451 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1452 lowSub = asSub(bLow, aLow.tsym);
1453 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1454 }
1455 if (highSub != null) {
1456 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1457 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1458 }
1459 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1460 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1461 && !disjointTypes(aLow.allparams(), highSub.allparams())
1462 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1463 if (upcast ? giveWarning(a, b) :
1464 giveWarning(b, a))
1465 warnStack.head.warn(LintCategory.UNCHECKED);
1466 return true;
1467 }
1468 }
1469 if (isReifiable(s))
1470 return isSubtypeUnchecked(a, b);
1471 else
1472 return isSubtypeUnchecked(a, b, warnStack.head);
1473 }
1474
1475 // Sidecast
1476 if (s.tag == CLASS) {
1477 if ((s.tsym.flags() & INTERFACE) != 0) {
1478 return ((t.tsym.flags() & FINAL) == 0)
1479 ? sideCast(t, s, warnStack.head)
1480 : sideCastFinal(t, s, warnStack.head);
1481 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1482 return ((s.tsym.flags() & FINAL) == 0)
1483 ? sideCast(t, s, warnStack.head)
1484 : sideCastFinal(t, s, warnStack.head);
1485 } else {
1486 // unrelated class types
1487 return false;
1488 }
1489 }
1490 }
1491 return false;
1492 }
1493
1494 boolean visitIntersectionType(IntersectionClassType ict, Type s, boolean reverse) {
1495 Warner warn = noWarnings;
1496 for (Type c : ict.getComponents()) {
1497 warn.clear();
1498 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
1499 return false;
1500 }
1501 if (warn.hasLint(LintCategory.UNCHECKED))
1502 warnStack.head.warn(LintCategory.UNCHECKED);
1503 return true;
1504 }
1505
1506 @Override
1507 public Boolean visitArrayType(ArrayType t, Type s) {
1508 switch (s.tag) {
1509 case ERROR:
1510 case BOT:
1511 return true;
1512 case TYPEVAR:
1513 if (isCastable(s, t, noWarnings)) {
1514 warnStack.head.warn(LintCategory.UNCHECKED);
1515 return true;
1516 } else {
1517 return false;
1518 }
1519 case CLASS:
1520 return isSubtype(t, s);
1521 case ARRAY:
1522 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1523 return elemtype(t).tag == elemtype(s).tag;
1524 } else {
1525 return visit(elemtype(t), elemtype(s));
1526 }
1527 default:
1528 return false;
1529 }
1530 }
1531
1532 @Override
1533 public Boolean visitTypeVar(TypeVar t, Type s) {
1534 switch (s.tag) {
1535 case ERROR:
1536 case BOT:
1537 return true;
1538 case TYPEVAR:
1539 if (isSubtype(t, s)) {
1540 return true;
1541 } else if (isCastable(t.bound, s, noWarnings)) {
1542 warnStack.head.warn(LintCategory.UNCHECKED);
1543 return true;
1544 } else {
1545 return false;
1546 }
1547 default:
1548 return isCastable(t.bound, s, warnStack.head);
1549 }
1550 }
1551
1552 @Override
1553 public Boolean visitErrorType(ErrorType t, Type s) {
1554 return true;
1555 }
1556 };
1557 // </editor-fold>
1558
1559 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1560 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1561 while (ts.tail != null && ss.tail != null) {
1562 if (disjointType(ts.head, ss.head)) return true;
1563 ts = ts.tail;
1564 ss = ss.tail;
1565 }
1566 return false;
1567 }
1568
1569 /**
1570 * Two types or wildcards are considered disjoint if it can be
1571 * proven that no type can be contained in both. It is
1572 * conservative in that it is allowed to say that two types are
1573 * not disjoint, even though they actually are.
1574 *
1575 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1576 * {@code X} and {@code Y} are not disjoint.
1577 */
1578 public boolean disjointType(Type t, Type s) {
1579 return disjointType.visit(t, s);
1580 }
1581 // where
1582 private TypeRelation disjointType = new TypeRelation() {
1583
1584 private Set<TypePair> cache = new HashSet<TypePair>();
1585
1586 public Boolean visitType(Type t, Type s) {
1587 if (s.tag == WILDCARD)
1588 return visit(s, t);
1589 else
1590 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1591 }
1592
1593 private boolean isCastableRecursive(Type t, Type s) {
1594 TypePair pair = new TypePair(t, s);
1595 if (cache.add(pair)) {
1596 try {
1597 return Types.this.isCastable(t, s);
1598 } finally {
1599 cache.remove(pair);
1600 }
1601 } else {
1602 return true;
1603 }
1604 }
1605
1606 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1607 TypePair pair = new TypePair(t, s);
1608 if (cache.add(pair)) {
1609 try {
1610 return Types.this.notSoftSubtype(t, s);
1611 } finally {
1612 cache.remove(pair);
1613 }
1614 } else {
1615 return false;
1616 }
1617 }
1618
1619 @Override
1620 public Boolean visitWildcardType(WildcardType t, Type s) {
1621 if (t.isUnbound())
1622 return false;
1623
1624 if (s.tag != WILDCARD) {
1625 if (t.isExtendsBound())
1626 return notSoftSubtypeRecursive(s, t.type);
1627 else // isSuperBound()
1628 return notSoftSubtypeRecursive(t.type, s);
1629 }
1630
1631 if (s.isUnbound())
1632 return false;
1633
1634 if (t.isExtendsBound()) {
1635 if (s.isExtendsBound())
1636 return !isCastableRecursive(t.type, upperBound(s));
1637 else if (s.isSuperBound())
1638 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1639 } else if (t.isSuperBound()) {
1640 if (s.isExtendsBound())
1641 return notSoftSubtypeRecursive(t.type, upperBound(s));
1642 }
1643 return false;
1644 }
1645 };
1646 // </editor-fold>
1647
1648 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1649 /**
1650 * Returns the lower bounds of the formals of a method.
1651 */
1652 public List<Type> lowerBoundArgtypes(Type t) {
1653 return lowerBounds(t.getParameterTypes());
1654 }
1655 public List<Type> lowerBounds(List<Type> ts) {
1656 return map(ts, lowerBoundMapping);
1657 }
1658 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1659 public Type apply(Type t) {
1660 return lowerBound(t);
1661 }
1662 };
1663 // </editor-fold>
1664
1665 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1666 /**
1667 * This relation answers the question: is impossible that
1668 * something of type `t' can be a subtype of `s'? This is
1669 * different from the question "is `t' not a subtype of `s'?"
1670 * when type variables are involved: Integer is not a subtype of T
1671 * where {@code <T extends Number>} but it is not true that Integer cannot
1672 * possibly be a subtype of T.
1673 */
1674 public boolean notSoftSubtype(Type t, Type s) {
1675 if (t == s) return false;
1676 if (t.tag == TYPEVAR) {
1677 TypeVar tv = (TypeVar) t;
1678 return !isCastable(tv.bound,
1679 relaxBound(s),
1680 noWarnings);
1681 }
1682 if (s.tag != WILDCARD)
1683 s = upperBound(s);
1684
1685 return !isSubtype(t, relaxBound(s));
1686 }
1687
1688 private Type relaxBound(Type t) {
1689 if (t.tag == TYPEVAR) {
1690 while (t.tag == TYPEVAR)
1691 t = t.getUpperBound();
1692 t = rewriteQuantifiers(t, true, true);
1693 }
1694 return t;
1695 }
1696 // </editor-fold>
1697
1698 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1699 public boolean isReifiable(Type t) {
1700 return isReifiable.visit(t);
1701 }
1702 // where
1703 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1704
1705 public Boolean visitType(Type t, Void ignored) {
1706 return true;
1707 }
1708
1709 @Override
1710 public Boolean visitClassType(ClassType t, Void ignored) {
1711 if (t.isCompound())
1712 return false;
1713 else {
1714 if (!t.isParameterized())
1715 return true;
1716
1717 for (Type param : t.allparams()) {
1718 if (!param.isUnbound())
1719 return false;
1720 }
1721 return true;
1722 }
1723 }
1724
1725 @Override
1726 public Boolean visitArrayType(ArrayType t, Void ignored) {
1727 return visit(t.elemtype);
1728 }
1729
1730 @Override
1731 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1732 return false;
1733 }
1734 };
1735 // </editor-fold>
1736
1737 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1738 public boolean isArray(Type t) {
1739 while (t.tag == WILDCARD)
1740 t = upperBound(t);
1741 return t.tag == ARRAY;
1742 }
1743
1744 /**
1745 * The element type of an array.
1746 */
1747 public Type elemtype(Type t) {
1748 switch (t.tag) {
1749 case WILDCARD:
1750 return elemtype(upperBound(t));
1751 case ARRAY:
1752 t = t.unannotatedType();
1753 return ((ArrayType)t).elemtype;
1754 case FORALL:
1755 return elemtype(((ForAll)t).qtype);
1756 case ERROR:
1757 return t;
1758 default:
1759 return null;
1760 }
1761 }
1762
1763 public Type elemtypeOrType(Type t) {
1764 Type elemtype = elemtype(t);
1765 return elemtype != null ?
1766 elemtype :
1767 t;
1768 }
1769
1770 /**
1771 * Mapping to take element type of an arraytype
1772 */
1773 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1774 public Type apply(Type t) { return elemtype(t); }
1775 };
1776
1777 /**
1778 * The number of dimensions of an array type.
1779 */
1780 public int dimensions(Type t) {
1781 int result = 0;
1782 while (t.tag == ARRAY) {
1783 result++;
1784 t = elemtype(t);
1785 }
1786 return result;
1787 }
1788
1789 /**
1790 * Returns an ArrayType with the component type t
1791 *
1792 * @param t The component type of the ArrayType
1793 * @return the ArrayType for the given component
1794 */
1795 public ArrayType makeArrayType(Type t) {
1796 if (t.tag == VOID ||
1797 t.tag == PACKAGE) {
1798 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
1799 }
1800 return new ArrayType(t, syms.arrayClass);
1801 }
1802 // </editor-fold>
1803
1804 // <editor-fold defaultstate="collapsed" desc="asSuper">
1805 /**
1806 * Return the (most specific) base type of t that starts with the
1807 * given symbol. If none exists, return null.
1808 *
1809 * @param t a type
1810 * @param sym a symbol
1811 */
1812 public Type asSuper(Type t, Symbol sym) {
1813 return asSuper.visit(t, sym);
1814 }
1815 // where
1816 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1817
1818 public Type visitType(Type t, Symbol sym) {
1819 return null;
1820 }
1821
1822 @Override
1823 public Type visitClassType(ClassType t, Symbol sym) {
1824 if (t.tsym == sym)
1825 return t;
1826
1827 Type st = supertype(t);
1828 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1829 Type x = asSuper(st, sym);
1830 if (x != null)
1831 return x;
1832 }
1833 if ((sym.flags() & INTERFACE) != 0) {
1834 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1835 Type x = asSuper(l.head, sym);
1836 if (x != null)
1837 return x;
1838 }
1839 }
1840 return null;
1841 }
1842
1843 @Override
1844 public Type visitArrayType(ArrayType t, Symbol sym) {
1845 return isSubtype(t, sym.type) ? sym.type : null;
1846 }
1847
1848 @Override
1849 public Type visitTypeVar(TypeVar t, Symbol sym) {
1850 if (t.tsym == sym)
1851 return t;
1852 else
1853 return asSuper(t.bound, sym);
1854 }
1855
1856 @Override
1857 public Type visitErrorType(ErrorType t, Symbol sym) {
1858 return t;
1859 }
1860 };
1861
1862 /**
1863 * Return the base type of t or any of its outer types that starts
1864 * with the given symbol. If none exists, return null.
1865 *
1866 * @param t a type
1867 * @param sym a symbol
1868 */
1869 public Type asOuterSuper(Type t, Symbol sym) {
1870 switch (t.tag) {
1871 case CLASS:
1872 do {
1873 Type s = asSuper(t, sym);
1874 if (s != null) return s;
1875 t = t.getEnclosingType();
1876 } while (t.tag == CLASS);
1877 return null;
1878 case ARRAY:
1879 return isSubtype(t, sym.type) ? sym.type : null;
1880 case TYPEVAR:
1881 return asSuper(t, sym);
1882 case ERROR:
1883 return t;
1884 default:
1885 return null;
1886 }
1887 }
1888
1889 /**
1890 * Return the base type of t or any of its enclosing types that
1891 * starts with the given symbol. If none exists, return null.
1892 *
1893 * @param t a type
1894 * @param sym a symbol
1895 */
1896 public Type asEnclosingSuper(Type t, Symbol sym) {
1897 switch (t.tag) {
1898 case CLASS:
1899 do {
1900 Type s = asSuper(t, sym);
1901 if (s != null) return s;
1902 Type outer = t.getEnclosingType();
1903 t = (outer.tag == CLASS) ? outer :
1904 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1905 Type.noType;
1906 } while (t.tag == CLASS);
1907 return null;
1908 case ARRAY:
1909 return isSubtype(t, sym.type) ? sym.type : null;
1910 case TYPEVAR:
1911 return asSuper(t, sym);
1912 case ERROR:
1913 return t;
1914 default:
1915 return null;
1916 }
1917 }
1918 // </editor-fold>
1919
1920 // <editor-fold defaultstate="collapsed" desc="memberType">
1921 /**
1922 * The type of given symbol, seen as a member of t.
1923 *
1924 * @param t a type
1925 * @param sym a symbol
1926 */
1927 public Type memberType(Type t, Symbol sym) {
1928 return (sym.flags() & STATIC) != 0
1929 ? sym.type
1930 : memberType.visit(t, sym);
1931 }
1932 // where
1933 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1934
1935 public Type visitType(Type t, Symbol sym) {
1936 return sym.type;
1937 }
1938
1939 @Override
1940 public Type visitWildcardType(WildcardType t, Symbol sym) {
1941 return memberType(upperBound(t), sym);
1942 }
1943
1944 @Override
1945 public Type visitClassType(ClassType t, Symbol sym) {
1946 Symbol owner = sym.owner;
1947 long flags = sym.flags();
1948 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1949 Type base = asOuterSuper(t, owner);
1950 //if t is an intersection type T = CT & I1 & I2 ... & In
1951 //its supertypes CT, I1, ... In might contain wildcards
1952 //so we need to go through capture conversion
1953 base = t.isCompound() ? capture(base) : base;
1954 if (base != null) {
1955 List<Type> ownerParams = owner.type.allparams();
1956 List<Type> baseParams = base.allparams();
1957 if (ownerParams.nonEmpty()) {
1958 if (baseParams.isEmpty()) {
1959 // then base is a raw type
1960 return erasure(sym.type);
1961 } else {
1962 return subst(sym.type, ownerParams, baseParams);
1963 }
1964 }
1965 }
1966 }
1967 return sym.type;
1968 }
1969
1970 @Override
1971 public Type visitTypeVar(TypeVar t, Symbol sym) {
1972 return memberType(t.bound, sym);
1973 }
1974
1975 @Override
1976 public Type visitErrorType(ErrorType t, Symbol sym) {
1977 return t;
1978 }
1979 };
1980 // </editor-fold>
1981
1982 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1983 public boolean isAssignable(Type t, Type s) {
1984 return isAssignable(t, s, noWarnings);
1985 }
1986
1987 /**
1988 * Is t assignable to s?<br>
1989 * Equivalent to subtype except for constant values and raw
1990 * types.<br>
1991 * (not defined for Method and ForAll types)
1992 */
1993 public boolean isAssignable(Type t, Type s, Warner warn) {
1994 if (t.tag == ERROR)
1995 return true;
1996 if (t.tag.isSubRangeOf(INT) && t.constValue() != null) {
1997 int value = ((Number)t.constValue()).intValue();
1998 switch (s.tag) {
1999 case BYTE:
2000 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
2001 return true;
2002 break;
2003 case CHAR:
2004 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
2005 return true;
2006 break;
2007 case SHORT:
2008 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
2009 return true;
2010 break;
2011 case INT:
2012 return true;
2013 case CLASS:
2014 switch (unboxedType(s).tag) {
2015 case BYTE:
2016 case CHAR:
2017 case SHORT:
2018 return isAssignable(t, unboxedType(s), warn);
2019 }
2020 break;
2021 }
2022 }
2023 return isConvertible(t, s, warn);
2024 }
2025 // </editor-fold>
2026
2027 // <editor-fold defaultstate="collapsed" desc="erasure">
2028 /**
2029 * The erasure of t {@code |t|} -- the type that results when all
2030 * type parameters in t are deleted.
2031 */
2032 public Type erasure(Type t) {
2033 return eraseNotNeeded(t)? t : erasure(t, false);
2034 }
2035 //where
2036 private boolean eraseNotNeeded(Type t) {
2037 // We don't want to erase primitive types and String type as that
2038 // operation is idempotent. Also, erasing these could result in loss
2039 // of information such as constant values attached to such types.
2040 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2041 }
2042
2043 private Type erasure(Type t, boolean recurse) {
2044 if (t.isPrimitive())
2045 return t; /* fast special case */
2046 else
2047 return erasure.visit(t, recurse);
2048 }
2049 // where
2050 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
2051 public Type visitType(Type t, Boolean recurse) {
2052 if (t.isPrimitive())
2053 return t; /*fast special case*/
2054 else
2055 return t.map(recurse ? erasureRecFun : erasureFun);
2056 }
2057
2058 @Override
2059 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2060 return erasure(upperBound(t), recurse);
2061 }
2062
2063 @Override
2064 public Type visitClassType(ClassType t, Boolean recurse) {
2065 Type erased = t.tsym.erasure(Types.this);
2066 if (recurse) {
2067 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
2068 }
2069 return erased;
2070 }
2071
2072 @Override
2073 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2074 return erasure(t.bound, recurse);
2075 }
2076
2077 @Override
2078 public Type visitErrorType(ErrorType t, Boolean recurse) {
2079 return t;
2080 }
2081
2082 @Override
2083 public Type visitAnnotatedType(AnnotatedType t, Boolean recurse) {
2084 Type erased = erasure(t.underlyingType, recurse);
2085 if (erased.isAnnotated()) {
2086 // This can only happen when the underlying type is a
2087 // type variable and the upper bound of it is annotated.
2088 // The annotation on the type variable overrides the one
2089 // on the bound.
2090 erased = ((AnnotatedType)erased).underlyingType;
2091 }
2092 return new AnnotatedType(t.typeAnnotations, erased);
2093 }
2094 };
2095
2096 private Mapping erasureFun = new Mapping ("erasure") {
2097 public Type apply(Type t) { return erasure(t); }
2098 };
2099
2100 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
2101 public Type apply(Type t) { return erasureRecursive(t); }
2102 };
2103
2104 public List<Type> erasure(List<Type> ts) {
2105 return Type.map(ts, erasureFun);
2106 }
2107
2108 public Type erasureRecursive(Type t) {
2109 return erasure(t, true);
2110 }
2111
2112 public List<Type> erasureRecursive(List<Type> ts) {
2113 return Type.map(ts, erasureRecFun);
2114 }
2115 // </editor-fold>
2116
2117 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
2118 /**
2119 * Make a compound type from non-empty list of types
2120 *
2121 * @param bounds the types from which the compound type is formed
2122 * @param supertype is objectType if all bounds are interfaces,
2123 * null otherwise.
2124 */
2125 public Type makeCompoundType(List<Type> bounds) {
2126 return makeCompoundType(bounds, bounds.head.tsym.isInterface());
2127 }
2128 public Type makeCompoundType(List<Type> bounds, boolean allInterfaces) {
2129 Assert.check(bounds.nonEmpty());
2130 Type firstExplicitBound = bounds.head;
2131 if (allInterfaces) {
2132 bounds = bounds.prepend(syms.objectType);
2133 }
2134 ClassSymbol bc =
2135 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2136 Type.moreInfo
2137 ? names.fromString(bounds.toString())
2138 : names.empty,
2139 null,
2140 syms.noSymbol);
2141 bc.type = new IntersectionClassType(bounds, bc, allInterfaces);
2142 bc.erasure_field = (bounds.head.tag == TYPEVAR) ?
2143 syms.objectType : // error condition, recover
2144 erasure(firstExplicitBound);
2145 bc.members_field = new Scope(bc);
2146 return bc.type;
2147 }
2148
2149 /**
2150 * A convenience wrapper for {@link #makeCompoundType(List)}; the
2151 * arguments are converted to a list and passed to the other
2152 * method. Note that this might cause a symbol completion.
2153 * Hence, this version of makeCompoundType may not be called
2154 * during a classfile read.
2155 */
2156 public Type makeCompoundType(Type bound1, Type bound2) {
2157 return makeCompoundType(List.of(bound1, bound2));
2158 }
2159 // </editor-fold>
2160
2161 // <editor-fold defaultstate="collapsed" desc="supertype">
2162 public Type supertype(Type t) {
2163 return supertype.visit(t);
2164 }
2165 // where
2166 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2167
2168 public Type visitType(Type t, Void ignored) {
2169 // A note on wildcards: there is no good way to
2170 // determine a supertype for a super bounded wildcard.
2171 return null;
2172 }
2173
2174 @Override
2175 public Type visitClassType(ClassType t, Void ignored) {
2176 if (t.supertype_field == null) {
2177 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2178 // An interface has no superclass; its supertype is Object.
2179 if (t.isInterface())
2180 supertype = ((ClassType)t.tsym.type).supertype_field;
2181 if (t.supertype_field == null) {
2182 List<Type> actuals = classBound(t).allparams();
2183 List<Type> formals = t.tsym.type.allparams();
2184 if (t.hasErasedSupertypes()) {
2185 t.supertype_field = erasureRecursive(supertype);
2186 } else if (formals.nonEmpty()) {
2187 t.supertype_field = subst(supertype, formals, actuals);
2188 }
2189 else {
2190 t.supertype_field = supertype;
2191 }
2192 }
2193 }
2194 return t.supertype_field;
2195 }
2196
2197 /**
2198 * The supertype is always a class type. If the type
2199 * variable's bounds start with a class type, this is also
2200 * the supertype. Otherwise, the supertype is
2201 * java.lang.Object.
2202 */
2203 @Override
2204 public Type visitTypeVar(TypeVar t, Void ignored) {
2205 if (t.bound.tag == TYPEVAR ||
2206 (!t.bound.isCompound() && !t.bound.isInterface())) {
2207 return t.bound;
2208 } else {
2209 return supertype(t.bound);
2210 }
2211 }
2212
2213 @Override
2214 public Type visitArrayType(ArrayType t, Void ignored) {
2215 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2216 return arraySuperType();
2217 else
2218 return new ArrayType(supertype(t.elemtype), t.tsym);
2219 }
2220
2221 @Override
2222 public Type visitErrorType(ErrorType t, Void ignored) {
2223 return t;
2224 }
2225 };
2226 // </editor-fold>
2227
2228 // <editor-fold defaultstate="collapsed" desc="interfaces">
2229 /**
2230 * Return the interfaces implemented by this class.
2231 */
2232 public List<Type> interfaces(Type t) {
2233 return interfaces.visit(t);
2234 }
2235 // where
2236 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2237
2238 public List<Type> visitType(Type t, Void ignored) {
2239 return List.nil();
2240 }
2241
2242 @Override
2243 public List<Type> visitClassType(ClassType t, Void ignored) {
2244 if (t.interfaces_field == null) {
2245 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2246 if (t.interfaces_field == null) {
2247 // If t.interfaces_field is null, then t must
2248 // be a parameterized type (not to be confused
2249 // with a generic type declaration).
2250 // Terminology:
2251 // Parameterized type: List<String>
2252 // Generic type declaration: class List<E> { ... }
2253 // So t corresponds to List<String> and
2254 // t.tsym.type corresponds to List<E>.
2255 // The reason t must be parameterized type is
2256 // that completion will happen as a side
2257 // effect of calling
2258 // ClassSymbol.getInterfaces. Since
2259 // t.interfaces_field is null after
2260 // completion, we can assume that t is not the
2261 // type of a class/interface declaration.
2262 Assert.check(t != t.tsym.type, t);
2263 List<Type> actuals = t.allparams();
2264 List<Type> formals = t.tsym.type.allparams();
2265 if (t.hasErasedSupertypes()) {
2266 t.interfaces_field = erasureRecursive(interfaces);
2267 } else if (formals.nonEmpty()) {
2268 t.interfaces_field =
2269 upperBounds(subst(interfaces, formals, actuals));
2270 }
2271 else {
2272 t.interfaces_field = interfaces;
2273 }
2274 }
2275 }
2276 return t.interfaces_field;
2277 }
2278
2279 @Override
2280 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2281 if (t.bound.isCompound())
2282 return interfaces(t.bound);
2283
2284 if (t.bound.isInterface())
2285 return List.of(t.bound);
2286
2287 return List.nil();
2288 }
2289 };
2290
2291 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2292 for (Type i2 : interfaces(origin.type)) {
2293 if (isym == i2.tsym) return true;
2294 }
2295 return false;
2296 }
2297 // </editor-fold>
2298
2299 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2300 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
2301
2302 public boolean isDerivedRaw(Type t) {
2303 Boolean result = isDerivedRawCache.get(t);
2304 if (result == null) {
2305 result = isDerivedRawInternal(t);
2306 isDerivedRawCache.put(t, result);
2307 }
2308 return result;
2309 }
2310
2311 public boolean isDerivedRawInternal(Type t) {
2312 if (t.isErroneous())
2313 return false;
2314 return
2315 t.isRaw() ||
2316 supertype(t) != null && isDerivedRaw(supertype(t)) ||
2317 isDerivedRaw(interfaces(t));
2318 }
2319
2320 public boolean isDerivedRaw(List<Type> ts) {
2321 List<Type> l = ts;
2322 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2323 return l.nonEmpty();
2324 }
2325 // </editor-fold>
2326
2327 // <editor-fold defaultstate="collapsed" desc="setBounds">
2328 /**
2329 * Set the bounds field of the given type variable to reflect a
2330 * (possibly multiple) list of bounds.
2331 * @param t a type variable
2332 * @param bounds the bounds, must be nonempty
2333 * @param supertype is objectType if all bounds are interfaces,
2334 * null otherwise.
2335 */
2336 public void setBounds(TypeVar t, List<Type> bounds) {
2337 setBounds(t, bounds, bounds.head.tsym.isInterface());
2338 }
2339
2340 /**
2341 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
2342 * third parameter is computed directly, as follows: if all
2343 * all bounds are interface types, the computed supertype is Object,
2344 * otherwise the supertype is simply left null (in this case, the supertype
2345 * is assumed to be the head of the bound list passed as second argument).
2346 * Note that this check might cause a symbol completion. Hence, this version of
2347 * setBounds may not be called during a classfile read.
2348 */
2349 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2350 t.bound = bounds.tail.isEmpty() ?
2351 bounds.head :
2352 makeCompoundType(bounds, allInterfaces);
2353 t.rank_field = -1;
2354 }
2355 // </editor-fold>
2356
2357 // <editor-fold defaultstate="collapsed" desc="getBounds">
2358 /**
2359 * Return list of bounds of the given type variable.
2360 */
2361 public List<Type> getBounds(TypeVar t) {
2362 if (t.bound.hasTag(NONE))
2363 return List.nil();
2364 else if (t.bound.isErroneous() || !t.bound.isCompound())
2365 return List.of(t.bound);
2366 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2367 return interfaces(t).prepend(supertype(t));
2368 else
2369 // No superclass was given in bounds.
2370 // In this case, supertype is Object, erasure is first interface.
2371 return interfaces(t);
2372 }
2373 // </editor-fold>
2374
2375 // <editor-fold defaultstate="collapsed" desc="classBound">
2376 /**
2377 * If the given type is a (possibly selected) type variable,
2378 * return the bounding class of this type, otherwise return the
2379 * type itself.
2380 */
2381 public Type classBound(Type t) {
2382 return classBound.visit(t);
2383 }
2384 // where
2385 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2386
2387 public Type visitType(Type t, Void ignored) {
2388 return t;
2389 }
2390
2391 @Override
2392 public Type visitClassType(ClassType t, Void ignored) {
2393 Type outer1 = classBound(t.getEnclosingType());
2394 if (outer1 != t.getEnclosingType())
2395 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
2396 else
2397 return t;
2398 }
2399
2400 @Override
2401 public Type visitTypeVar(TypeVar t, Void ignored) {
2402 return classBound(supertype(t));
2403 }
2404
2405 @Override
2406 public Type visitErrorType(ErrorType t, Void ignored) {
2407 return t;
2408 }
2409 };
2410 // </editor-fold>
2411
2412 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
2413 /**
2414 * Returns true iff the first signature is a <em>sub
2415 * signature</em> of the other. This is <b>not</b> an equivalence
2416 * relation.
2417 *
2418 * @jls section 8.4.2.
2419 * @see #overrideEquivalent(Type t, Type s)
2420 * @param t first signature (possibly raw).
2421 * @param s second signature (could be subjected to erasure).
2422 * @return true if t is a sub signature of s.
2423 */
2424 public boolean isSubSignature(Type t, Type s) {
2425 return isSubSignature(t, s, true);
2426 }
2427
2428 public boolean isSubSignature(Type t, Type s, boolean strict) {
2429 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2430 }
2431
2432 /**
2433 * Returns true iff these signatures are related by <em>override
2434 * equivalence</em>. This is the natural extension of
2435 * isSubSignature to an equivalence relation.
2436 *
2437 * @jls section 8.4.2.
2438 * @see #isSubSignature(Type t, Type s)
2439 * @param t a signature (possible raw, could be subjected to
2440 * erasure).
2441 * @param s a signature (possible raw, could be subjected to
2442 * erasure).
2443 * @return true if either argument is a sub signature of the other.
2444 */
2445 public boolean overrideEquivalent(Type t, Type s) {
2446 return hasSameArgs(t, s) ||
2447 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2448 }
2449
2450 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2451 for (Scope.Entry e = syms.objectType.tsym.members().lookup(msym.name) ; e.scope != null ; e = e.next()) {
2452 if (msym.overrides(e.sym, origin, Types.this, true)) {
2453 return true;
2454 }
2455 }
2456 return false;
2457 }
2458
2459 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2460 class ImplementationCache {
2461
2462 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
2463 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
2464
2465 class Entry {
2466 final MethodSymbol cachedImpl;
2467 final Filter<Symbol> implFilter;
2468 final boolean checkResult;
2469 final int prevMark;
2470
2471 public Entry(MethodSymbol cachedImpl,
2472 Filter<Symbol> scopeFilter,
2473 boolean checkResult,
2474 int prevMark) {
2475 this.cachedImpl = cachedImpl;
2476 this.implFilter = scopeFilter;
2477 this.checkResult = checkResult;
2478 this.prevMark = prevMark;
2479 }
2480
2481 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
2482 return this.implFilter == scopeFilter &&
2483 this.checkResult == checkResult &&
2484 this.prevMark == mark;
2485 }
2486 }
2487
2488 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2489 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2490 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2491 if (cache == null) {
2492 cache = new HashMap<TypeSymbol, Entry>();
2493 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2494 }
2495 Entry e = cache.get(origin);
2496 CompoundScope members = membersClosure(origin.type, true);
2497 if (e == null ||
2498 !e.matches(implFilter, checkResult, members.getMark())) {
2499 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2500 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2501 return impl;
2502 }
2503 else {
2504 return e.cachedImpl;
2505 }
2506 }
2507
2508 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2509 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = supertype(t)) {
2510 while (t.tag == TYPEVAR)
2511 t = t.getUpperBound();
2512 TypeSymbol c = t.tsym;
2513 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2514 e.scope != null;
2515 e = e.next(implFilter)) {
2516 if (e.sym != null &&
2517 e.sym.overrides(ms, origin, Types.this, checkResult))
2518 return (MethodSymbol)e.sym;
2519 }
2520 }
2521 return null;
2522 }
2523 }
2524
2525 private ImplementationCache implCache = new ImplementationCache();
2526
2527 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2528 return implCache.get(ms, origin, checkResult, implFilter);
2529 }
2530 // </editor-fold>
2531
2532 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2533 class MembersClosureCache extends SimpleVisitor<CompoundScope, Boolean> {
2534
2535 private WeakHashMap<TypeSymbol, Entry> _map =
2536 new WeakHashMap<TypeSymbol, Entry>();
2537
2538 class Entry {
2539 final boolean skipInterfaces;
2540 final CompoundScope compoundScope;
2541
2542 public Entry(boolean skipInterfaces, CompoundScope compoundScope) {
2543 this.skipInterfaces = skipInterfaces;
2544 this.compoundScope = compoundScope;
2545 }
2546
2547 boolean matches(boolean skipInterfaces) {
2548 return this.skipInterfaces == skipInterfaces;
2549 }
2550 }
2551
2552 List<TypeSymbol> seenTypes = List.nil();
2553
2554 /** members closure visitor methods **/
2555
2556 public CompoundScope visitType(Type t, Boolean skipInterface) {
2557 return null;
2558 }
2559
2560 @Override
2561 public CompoundScope visitClassType(ClassType t, Boolean skipInterface) {
2562 if (seenTypes.contains(t.tsym)) {
2563 //this is possible when an interface is implemented in multiple
2564 //superclasses, or when a classs hierarchy is circular - in such
2565 //cases we don't need to recurse (empty scope is returned)
2566 return new CompoundScope(t.tsym);
2567 }
2568 try {
2569 seenTypes = seenTypes.prepend(t.tsym);
2570 ClassSymbol csym = (ClassSymbol)t.tsym;
2571 Entry e = _map.get(csym);
2572 if (e == null || !e.matches(skipInterface)) {
2573 CompoundScope membersClosure = new CompoundScope(csym);
2574 if (!skipInterface) {
2575 for (Type i : interfaces(t)) {
2576 membersClosure.addSubScope(visit(i, skipInterface));
2577 }
2578 }
2579 membersClosure.addSubScope(visit(supertype(t), skipInterface));
2580 membersClosure.addSubScope(csym.members());
2581 e = new Entry(skipInterface, membersClosure);
2582 _map.put(csym, e);
2583 }
2584 return e.compoundScope;
2585 }
2586 finally {
2587 seenTypes = seenTypes.tail;
2588 }
2589 }
2590
2591 @Override
2592 public CompoundScope visitTypeVar(TypeVar t, Boolean skipInterface) {
2593 return visit(t.getUpperBound(), skipInterface);
2594 }
2595 }
2596
2597 private MembersClosureCache membersCache = new MembersClosureCache();
2598
2599 public CompoundScope membersClosure(Type site, boolean skipInterface) {
2600 return membersCache.visit(site, skipInterface);
2601 }
2602 // </editor-fold>
2603
2604
2605 //where
2606 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
2607 Filter<Symbol> filter = new MethodFilter(ms, site);
2608 List<MethodSymbol> candidates = List.nil();
2609 for (Symbol s : membersClosure(site, false).getElements(filter)) {
2610 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
2611 return List.of((MethodSymbol)s);
2612 } else if (!candidates.contains(s)) {
2613 candidates = candidates.prepend((MethodSymbol)s);
2614 }
2615 }
2616 return prune(candidates);
2617 }
2618
2619 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
2620 ListBuffer<MethodSymbol> methodsMin = ListBuffer.lb();
2621 for (MethodSymbol m1 : methods) {
2622 boolean isMin_m1 = true;
2623 for (MethodSymbol m2 : methods) {
2624 if (m1 == m2) continue;
2625 if (m2.owner != m1.owner &&
2626 asSuper(m2.owner.type, m1.owner) != null) {
2627 isMin_m1 = false;
2628 break;
2629 }
2630 }
2631 if (isMin_m1)
2632 methodsMin.append(m1);
2633 }
2634 return methodsMin.toList();
2635 }
2636 // where
2637 private class MethodFilter implements Filter<Symbol> {
2638
2639 Symbol msym;
2640 Type site;
2641
2642 MethodFilter(Symbol msym, Type site) {
2643 this.msym = msym;
2644 this.site = site;
2645 }
2646
2647 public boolean accepts(Symbol s) {
2648 return s.kind == Kinds.MTH &&
2649 s.name == msym.name &&
2650 s.isInheritedIn(site.tsym, Types.this) &&
2651 overrideEquivalent(memberType(site, s), memberType(site, msym));
2652 }
2653 };
2654 // </editor-fold>
2655
2656 /**
2657 * Does t have the same arguments as s? It is assumed that both
2658 * types are (possibly polymorphic) method types. Monomorphic
2659 * method types "have the same arguments", if their argument lists
2660 * are equal. Polymorphic method types "have the same arguments",
2661 * if they have the same arguments after renaming all type
2662 * variables of one to corresponding type variables in the other,
2663 * where correspondence is by position in the type parameter list.
2664 */
2665 public boolean hasSameArgs(Type t, Type s) {
2666 return hasSameArgs(t, s, true);
2667 }
2668
2669 public boolean hasSameArgs(Type t, Type s, boolean strict) {
2670 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
2671 }
2672
2673 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
2674 return hasSameArgs.visit(t, s);
2675 }
2676 // where
2677 private class HasSameArgs extends TypeRelation {
2678
2679 boolean strict;
2680
2681 public HasSameArgs(boolean strict) {
2682 this.strict = strict;
2683 }
2684
2685 public Boolean visitType(Type t, Type s) {
2686 throw new AssertionError();
2687 }
2688
2689 @Override
2690 public Boolean visitMethodType(MethodType t, Type s) {
2691 return s.tag == METHOD
2692 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2693 }
2694
2695 @Override
2696 public Boolean visitForAll(ForAll t, Type s) {
2697 if (s.tag != FORALL)
2698 return strict ? false : visitMethodType(t.asMethodType(), s);
2699
2700 ForAll forAll = (ForAll)s;
2701 return hasSameBounds(t, forAll)
2702 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2703 }
2704
2705 @Override
2706 public Boolean visitErrorType(ErrorType t, Type s) {
2707 return false;
2708 }
2709 };
2710
2711 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
2712 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
2713
2714 // </editor-fold>
2715
2716 // <editor-fold defaultstate="collapsed" desc="subst">
2717 public List<Type> subst(List<Type> ts,
2718 List<Type> from,
2719 List<Type> to) {
2720 return new Subst(from, to).subst(ts);
2721 }
2722
2723 /**
2724 * Substitute all occurrences of a type in `from' with the
2725 * corresponding type in `to' in 't'. Match lists `from' and `to'
2726 * from the right: If lists have different length, discard leading
2727 * elements of the longer list.
2728 */
2729 public Type subst(Type t, List<Type> from, List<Type> to) {
2730 return new Subst(from, to).subst(t);
2731 }
2732
2733 private class Subst extends UnaryVisitor<Type> {
2734 List<Type> from;
2735 List<Type> to;
2736
2737 public Subst(List<Type> from, List<Type> to) {
2738 int fromLength = from.length();
2739 int toLength = to.length();
2740 while (fromLength > toLength) {
2741 fromLength--;
2742 from = from.tail;
2743 }
2744 while (fromLength < toLength) {
2745 toLength--;
2746 to = to.tail;
2747 }
2748 this.from = from;
2749 this.to = to;
2750 }
2751
2752 Type subst(Type t) {
2753 if (from.tail == null)
2754 return t;
2755 else
2756 return visit(t);
2757 }
2758
2759 List<Type> subst(List<Type> ts) {
2760 if (from.tail == null)
2761 return ts;
2762 boolean wild = false;
2763 if (ts.nonEmpty() && from.nonEmpty()) {
2764 Type head1 = subst(ts.head);
2765 List<Type> tail1 = subst(ts.tail);
2766 if (head1 != ts.head || tail1 != ts.tail)
2767 return tail1.prepend(head1);
2768 }
2769 return ts;
2770 }
2771
2772 public Type visitType(Type t, Void ignored) {
2773 return t;
2774 }
2775
2776 @Override
2777 public Type visitMethodType(MethodType t, Void ignored) {
2778 List<Type> argtypes = subst(t.argtypes);
2779 Type restype = subst(t.restype);
2780 List<Type> thrown = subst(t.thrown);
2781 if (argtypes == t.argtypes &&
2782 restype == t.restype &&
2783 thrown == t.thrown)
2784 return t;
2785 else
2786 return new MethodType(argtypes, restype, thrown, t.tsym);
2787 }
2788
2789 @Override
2790 public Type visitTypeVar(TypeVar t, Void ignored) {
2791 for (List<Type> from = this.from, to = this.to;
2792 from.nonEmpty();
2793 from = from.tail, to = to.tail) {
2794 if (t == from.head) {
2795 return to.head.withTypeVar(t);
2796 }
2797 }
2798 return t;
2799 }
2800
2801 @Override
2802 public Type visitClassType(ClassType t, Void ignored) {
2803 if (!t.isCompound()) {
2804 List<Type> typarams = t.getTypeArguments();
2805 List<Type> typarams1 = subst(typarams);
2806 Type outer = t.getEnclosingType();
2807 Type outer1 = subst(outer);
2808 if (typarams1 == typarams && outer1 == outer)
2809 return t;
2810 else
2811 return new ClassType(outer1, typarams1, t.tsym);
2812 } else {
2813 Type st = subst(supertype(t));
2814 List<Type> is = upperBounds(subst(interfaces(t)));
2815 if (st == supertype(t) && is == interfaces(t))
2816 return t;
2817 else
2818 return makeCompoundType(is.prepend(st));
2819 }
2820 }
2821
2822 @Override
2823 public Type visitWildcardType(WildcardType t, Void ignored) {
2824 Type bound = t.type;
2825 if (t.kind != BoundKind.UNBOUND)
2826 bound = subst(bound);
2827 if (bound == t.type) {
2828 return t;
2829 } else {
2830 if (t.isExtendsBound() && bound.isExtendsBound())
2831 bound = upperBound(bound);
2832 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2833 }
2834 }
2835
2836 @Override
2837 public Type visitArrayType(ArrayType t, Void ignored) {
2838 Type elemtype = subst(t.elemtype);
2839 if (elemtype == t.elemtype)
2840 return t;
2841 else
2842 return new ArrayType(upperBound(elemtype), t.tsym);
2843 }
2844
2845 @Override
2846 public Type visitForAll(ForAll t, Void ignored) {
2847 if (Type.containsAny(to, t.tvars)) {
2848 //perform alpha-renaming of free-variables in 't'
2849 //if 'to' types contain variables that are free in 't'
2850 List<Type> freevars = newInstances(t.tvars);
2851 t = new ForAll(freevars,
2852 Types.this.subst(t.qtype, t.tvars, freevars));
2853 }
2854 List<Type> tvars1 = substBounds(t.tvars, from, to);
2855 Type qtype1 = subst(t.qtype);
2856 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2857 return t;
2858 } else if (tvars1 == t.tvars) {
2859 return new ForAll(tvars1, qtype1);
2860 } else {
2861 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2862 }
2863 }
2864
2865 @Override
2866 public Type visitErrorType(ErrorType t, Void ignored) {
2867 return t;
2868 }
2869 }
2870
2871 public List<Type> substBounds(List<Type> tvars,
2872 List<Type> from,
2873 List<Type> to) {
2874 if (tvars.isEmpty())
2875 return tvars;
2876 ListBuffer<Type> newBoundsBuf = lb();
2877 boolean changed = false;
2878 // calculate new bounds
2879 for (Type t : tvars) {
2880 TypeVar tv = (TypeVar) t;
2881 Type bound = subst(tv.bound, from, to);
2882 if (bound != tv.bound)
2883 changed = true;
2884 newBoundsBuf.append(bound);
2885 }
2886 if (!changed)
2887 return tvars;
2888 ListBuffer<Type> newTvars = lb();
2889 // create new type variables without bounds
2890 for (Type t : tvars) {
2891 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2892 }
2893 // the new bounds should use the new type variables in place
2894 // of the old
2895 List<Type> newBounds = newBoundsBuf.toList();
2896 from = tvars;
2897 to = newTvars.toList();
2898 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2899 newBounds.head = subst(newBounds.head, from, to);
2900 }
2901 newBounds = newBoundsBuf.toList();
2902 // set the bounds of new type variables to the new bounds
2903 for (Type t : newTvars.toList()) {
2904 TypeVar tv = (TypeVar) t;
2905 tv.bound = newBounds.head;
2906 newBounds = newBounds.tail;
2907 }
2908 return newTvars.toList();
2909 }
2910
2911 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2912 Type bound1 = subst(t.bound, from, to);
2913 if (bound1 == t.bound)
2914 return t;
2915 else {
2916 // create new type variable without bounds
2917 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2918 // the new bound should use the new type variable in place
2919 // of the old
2920 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2921 return tv;
2922 }
2923 }
2924 // </editor-fold>
2925
2926 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2927 /**
2928 * Does t have the same bounds for quantified variables as s?
2929 */
2930 boolean hasSameBounds(ForAll t, ForAll s) {
2931 List<Type> l1 = t.tvars;
2932 List<Type> l2 = s.tvars;
2933 while (l1.nonEmpty() && l2.nonEmpty() &&
2934 isSameType(l1.head.getUpperBound(),
2935 subst(l2.head.getUpperBound(),
2936 s.tvars,
2937 t.tvars))) {
2938 l1 = l1.tail;
2939 l2 = l2.tail;
2940 }
2941 return l1.isEmpty() && l2.isEmpty();
2942 }
2943 // </editor-fold>
2944
2945 // <editor-fold defaultstate="collapsed" desc="newInstances">
2946 /** Create new vector of type variables from list of variables
2947 * changing all recursive bounds from old to new list.
2948 */
2949 public List<Type> newInstances(List<Type> tvars) {
2950 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2951 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2952 TypeVar tv = (TypeVar) l.head;
2953 tv.bound = subst(tv.bound, tvars, tvars1);
2954 }
2955 return tvars1;
2956 }
2957 private static final Mapping newInstanceFun = new Mapping("newInstanceFun") {
2958 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2959 };
2960 // </editor-fold>
2961
2962 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
2963 return original.accept(methodWithParameters, newParams);
2964 }
2965 // where
2966 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
2967 public Type visitType(Type t, List<Type> newParams) {
2968 throw new IllegalArgumentException("Not a method type: " + t);
2969 }
2970 public Type visitMethodType(MethodType t, List<Type> newParams) {
2971 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
2972 }
2973 public Type visitForAll(ForAll t, List<Type> newParams) {
2974 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
2975 }
2976 };
2977
2978 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
2979 return original.accept(methodWithThrown, newThrown);
2980 }
2981 // where
2982 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
2983 public Type visitType(Type t, List<Type> newThrown) {
2984 throw new IllegalArgumentException("Not a method type: " + t);
2985 }
2986 public Type visitMethodType(MethodType t, List<Type> newThrown) {
2987 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
2988 }
2989 public Type visitForAll(ForAll t, List<Type> newThrown) {
2990 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
2991 }
2992 };
2993
2994 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
2995 return original.accept(methodWithReturn, newReturn);
2996 }
2997 // where
2998 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
2999 public Type visitType(Type t, Type newReturn) {
3000 throw new IllegalArgumentException("Not a method type: " + t);
3001 }
3002 public Type visitMethodType(MethodType t, Type newReturn) {
3003 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym);
3004 }
3005 public Type visitForAll(ForAll t, Type newReturn) {
3006 return new ForAll(t.tvars, t.qtype.accept(this, newReturn));
3007 }
3008 };
3009
3010 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3011 public Type createErrorType(Type originalType) {
3012 return new ErrorType(originalType, syms.errSymbol);
3013 }
3014
3015 public Type createErrorType(ClassSymbol c, Type originalType) {
3016 return new ErrorType(c, originalType);
3017 }
3018
3019 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3020 return new ErrorType(name, container, originalType);
3021 }
3022 // </editor-fold>
3023
3024 // <editor-fold defaultstate="collapsed" desc="rank">
3025 /**
3026 * The rank of a class is the length of the longest path between
3027 * the class and java.lang.Object in the class inheritance
3028 * graph. Undefined for all but reference types.
3029 */
3030 public int rank(Type t) {
3031 t = t.unannotatedType();
3032 switch(t.tag) {
3033 case CLASS: {
3034 ClassType cls = (ClassType)t;
3035 if (cls.rank_field < 0) {
3036 Name fullname = cls.tsym.getQualifiedName();
3037 if (fullname == names.java_lang_Object)
3038 cls.rank_field = 0;
3039 else {
3040 int r = rank(supertype(cls));
3041 for (List<Type> l = interfaces(cls);
3042 l.nonEmpty();
3043 l = l.tail) {
3044 if (rank(l.head) > r)
3045 r = rank(l.head);
3046 }
3047 cls.rank_field = r + 1;
3048 }
3049 }
3050 return cls.rank_field;
3051 }
3052 case TYPEVAR: {
3053 TypeVar tvar = (TypeVar)t;
3054 if (tvar.rank_field < 0) {
3055 int r = rank(supertype(tvar));
3056 for (List<Type> l = interfaces(tvar);
3057 l.nonEmpty();
3058 l = l.tail) {
3059 if (rank(l.head) > r) r = rank(l.head);
3060 }
3061 tvar.rank_field = r + 1;
3062 }
3063 return tvar.rank_field;
3064 }
3065 case ERROR:
3066 return 0;
3067 default:
3068 throw new AssertionError();
3069 }
3070 }
3071 // </editor-fold>
3072
3073 /**
3074 * Helper method for generating a string representation of a given type
3075 * accordingly to a given locale
3076 */
3077 public String toString(Type t, Locale locale) {
3078 return Printer.createStandardPrinter(messages).visit(t, locale);
3079 }
3080
3081 /**
3082 * Helper method for generating a string representation of a given type
3083 * accordingly to a given locale
3084 */
3085 public String toString(Symbol t, Locale locale) {
3086 return Printer.createStandardPrinter(messages).visit(t, locale);
3087 }
3088
3089 // <editor-fold defaultstate="collapsed" desc="toString">
3090 /**
3091 * This toString is slightly more descriptive than the one on Type.
3092 *
3093 * @deprecated Types.toString(Type t, Locale l) provides better support
3094 * for localization
3095 */
3096 @Deprecated
3097 public String toString(Type t) {
3098 if (t.tag == FORALL) {
3099 ForAll forAll = (ForAll)t;
3100 return typaramsString(forAll.tvars) + forAll.qtype;
3101 }
3102 return "" + t;
3103 }
3104 // where
3105 private String typaramsString(List<Type> tvars) {
3106 StringBuilder s = new StringBuilder();
3107 s.append('<');
3108 boolean first = true;
3109 for (Type t : tvars) {
3110 if (!first) s.append(", ");
3111 first = false;
3112 appendTyparamString(((TypeVar)t.unannotatedType()), s);
3113 }
3114 s.append('>');
3115 return s.toString();
3116 }
3117 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3118 buf.append(t);
3119 if (t.bound == null ||
3120 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
3121 return;
3122 buf.append(" extends "); // Java syntax; no need for i18n
3123 Type bound = t.bound;
3124 if (!bound.isCompound()) {
3125 buf.append(bound);
3126 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3127 buf.append(supertype(t));
3128 for (Type intf : interfaces(t)) {
3129 buf.append('&');
3130 buf.append(intf);
3131 }
3132 } else {
3133 // No superclass was given in bounds.
3134 // In this case, supertype is Object, erasure is first interface.
3135 boolean first = true;
3136 for (Type intf : interfaces(t)) {
3137 if (!first) buf.append('&');
3138 first = false;
3139 buf.append(intf);
3140 }
3141 }
3142 }
3143 // </editor-fold>
3144
3145 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3146 /**
3147 * A cache for closures.
3148 *
3149 * <p>A closure is a list of all the supertypes and interfaces of
3150 * a class or interface type, ordered by ClassSymbol.precedes
3151 * (that is, subclasses come first, arbitrary but fixed
3152 * otherwise).
3153 */
3154 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
3155
3156 /**
3157 * Returns the closure of a class or interface type.
3158 */
3159 public List<Type> closure(Type t) {
3160 List<Type> cl = closureCache.get(t);
3161 if (cl == null) {
3162 Type st = supertype(t);
3163 if (!t.isCompound()) {
3164 if (st.tag == CLASS) {
3165 cl = insert(closure(st), t);
3166 } else if (st.tag == TYPEVAR) {
3167 cl = closure(st).prepend(t);
3168 } else {
3169 cl = List.of(t);
3170 }
3171 } else {
3172 cl = closure(supertype(t));
3173 }
3174 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3175 cl = union(cl, closure(l.head));
3176 closureCache.put(t, cl);
3177 }
3178 return cl;
3179 }
3180
3181 /**
3182 * Insert a type in a closure
3183 */
3184 public List<Type> insert(List<Type> cl, Type t) {
3185 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
3186 return cl.prepend(t);
3187 } else if (cl.head.tsym.precedes(t.tsym, this)) {
3188 return insert(cl.tail, t).prepend(cl.head);
3189 } else {
3190 return cl;
3191 }
3192 }
3193
3194 /**
3195 * Form the union of two closures
3196 */
3197 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3198 if (cl1.isEmpty()) {
3199 return cl2;
3200 } else if (cl2.isEmpty()) {
3201 return cl1;
3202 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
3203 return union(cl1.tail, cl2).prepend(cl1.head);
3204 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3205 return union(cl1, cl2.tail).prepend(cl2.head);
3206 } else {
3207 return union(cl1.tail, cl2.tail).prepend(cl1.head);
3208 }
3209 }
3210
3211 /**
3212 * Intersect two closures
3213 */
3214 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3215 if (cl1 == cl2)
3216 return cl1;
3217 if (cl1.isEmpty() || cl2.isEmpty())
3218 return List.nil();
3219 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3220 return intersect(cl1.tail, cl2);
3221 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3222 return intersect(cl1, cl2.tail);
3223 if (isSameType(cl1.head, cl2.head))
3224 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3225 if (cl1.head.tsym == cl2.head.tsym &&
3226 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
3227 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3228 Type merge = merge(cl1.head,cl2.head);
3229 return intersect(cl1.tail, cl2.tail).prepend(merge);
3230 }
3231 if (cl1.head.isRaw() || cl2.head.isRaw())
3232 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3233 }
3234 return intersect(cl1.tail, cl2.tail);
3235 }
3236 // where
3237 class TypePair {
3238 final Type t1;
3239 final Type t2;
3240 TypePair(Type t1, Type t2) {
3241 this.t1 = t1;
3242 this.t2 = t2;
3243 }
3244 @Override
3245 public int hashCode() {
3246 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3247 }
3248 @Override
3249 public boolean equals(Object obj) {
3250 if (!(obj instanceof TypePair))
3251 return false;
3252 TypePair typePair = (TypePair)obj;
3253 return isSameType(t1, typePair.t1)
3254 && isSameType(t2, typePair.t2);
3255 }
3256 }
3257 Set<TypePair> mergeCache = new HashSet<TypePair>();
3258 private Type merge(Type c1, Type c2) {
3259 ClassType class1 = (ClassType) c1;
3260 List<Type> act1 = class1.getTypeArguments();
3261 ClassType class2 = (ClassType) c2;
3262 List<Type> act2 = class2.getTypeArguments();
3263 ListBuffer<Type> merged = new ListBuffer<Type>();
3264 List<Type> typarams = class1.tsym.type.getTypeArguments();
3265
3266 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3267 if (containsType(act1.head, act2.head)) {
3268 merged.append(act1.head);
3269 } else if (containsType(act2.head, act1.head)) {
3270 merged.append(act2.head);
3271 } else {
3272 TypePair pair = new TypePair(c1, c2);
3273 Type m;
3274 if (mergeCache.add(pair)) {
3275 m = new WildcardType(lub(upperBound(act1.head),
3276 upperBound(act2.head)),
3277 BoundKind.EXTENDS,
3278 syms.boundClass);
3279 mergeCache.remove(pair);
3280 } else {
3281 m = new WildcardType(syms.objectType,
3282 BoundKind.UNBOUND,
3283 syms.boundClass);
3284 }
3285 merged.append(m.withTypeVar(typarams.head));
3286 }
3287 act1 = act1.tail;
3288 act2 = act2.tail;
3289 typarams = typarams.tail;
3290 }
3291 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3292 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
3293 }
3294
3295 /**
3296 * Return the minimum type of a closure, a compound type if no
3297 * unique minimum exists.
3298 */
3299 private Type compoundMin(List<Type> cl) {
3300 if (cl.isEmpty()) return syms.objectType;
3301 List<Type> compound = closureMin(cl);
3302 if (compound.isEmpty())
3303 return null;
3304 else if (compound.tail.isEmpty())
3305 return compound.head;
3306 else
3307 return makeCompoundType(compound);
3308 }
3309
3310 /**
3311 * Return the minimum types of a closure, suitable for computing
3312 * compoundMin or glb.
3313 */
3314 private List<Type> closureMin(List<Type> cl) {
3315 ListBuffer<Type> classes = lb();
3316 ListBuffer<Type> interfaces = lb();
3317 while (!cl.isEmpty()) {
3318 Type current = cl.head;
3319 if (current.isInterface())
3320 interfaces.append(current);
3321 else
3322 classes.append(current);
3323 ListBuffer<Type> candidates = lb();
3324 for (Type t : cl.tail) {
3325 if (!isSubtypeNoCapture(current, t))
3326 candidates.append(t);
3327 }
3328 cl = candidates.toList();
3329 }
3330 return classes.appendList(interfaces).toList();
3331 }
3332
3333 /**
3334 * Return the least upper bound of pair of types. if the lub does
3335 * not exist return null.
3336 */
3337 public Type lub(Type t1, Type t2) {
3338 return lub(List.of(t1, t2));
3339 }
3340
3341 /**
3342 * Return the least upper bound (lub) of set of types. If the lub
3343 * does not exist return the type of null (bottom).
3344 */
3345 public Type lub(List<Type> ts) {
3346 final int ARRAY_BOUND = 1;
3347 final int CLASS_BOUND = 2;
3348 int boundkind = 0;
3349 for (Type t : ts) {
3350 switch (t.tag) {
3351 case CLASS:
3352 boundkind |= CLASS_BOUND;
3353 break;
3354 case ARRAY:
3355 boundkind |= ARRAY_BOUND;
3356 break;
3357 case TYPEVAR:
3358 do {
3359 t = t.getUpperBound();
3360 } while (t.tag == TYPEVAR);
3361 if (t.tag == ARRAY) {
3362 boundkind |= ARRAY_BOUND;
3363 } else {
3364 boundkind |= CLASS_BOUND;
3365 }
3366 break;
3367 default:
3368 if (t.isPrimitive())
3369 return syms.errType;
3370 }
3371 }
3372 switch (boundkind) {
3373 case 0:
3374 return syms.botType;
3375
3376 case ARRAY_BOUND:
3377 // calculate lub(A[], B[])
3378 List<Type> elements = Type.map(ts, elemTypeFun);
3379 for (Type t : elements) {
3380 if (t.isPrimitive()) {
3381 // if a primitive type is found, then return
3382 // arraySuperType unless all the types are the
3383 // same
3384 Type first = ts.head;
3385 for (Type s : ts.tail) {
3386 if (!isSameType(first, s)) {
3387 // lub(int[], B[]) is Cloneable & Serializable
3388 return arraySuperType();
3389 }
3390 }
3391 // all the array types are the same, return one
3392 // lub(int[], int[]) is int[]
3393 return first;
3394 }
3395 }
3396 // lub(A[], B[]) is lub(A, B)[]
3397 return new ArrayType(lub(elements), syms.arrayClass);
3398
3399 case CLASS_BOUND:
3400 // calculate lub(A, B)
3401 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
3402 ts = ts.tail;
3403 Assert.check(!ts.isEmpty());
3404 //step 1 - compute erased candidate set (EC)
3405 List<Type> cl = erasedSupertypes(ts.head);
3406 for (Type t : ts.tail) {
3407 if (t.tag == CLASS || t.tag == TYPEVAR)
3408 cl = intersect(cl, erasedSupertypes(t));
3409 }
3410 //step 2 - compute minimal erased candidate set (MEC)
3411 List<Type> mec = closureMin(cl);
3412 //step 3 - for each element G in MEC, compute lci(Inv(G))
3413 List<Type> candidates = List.nil();
3414 for (Type erasedSupertype : mec) {
3415 List<Type> lci = List.of(asSuper(ts.head, erasedSupertype.tsym));
3416 for (Type t : ts) {
3417 lci = intersect(lci, List.of(asSuper(t, erasedSupertype.tsym)));
3418 }
3419 candidates = candidates.appendList(lci);
3420 }
3421 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
3422 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
3423 return compoundMin(candidates);
3424
3425 default:
3426 // calculate lub(A, B[])
3427 List<Type> classes = List.of(arraySuperType());
3428 for (Type t : ts) {
3429 if (t.tag != ARRAY) // Filter out any arrays
3430 classes = classes.prepend(t);
3431 }
3432 // lub(A, B[]) is lub(A, arraySuperType)
3433 return lub(classes);
3434 }
3435 }
3436 // where
3437 List<Type> erasedSupertypes(Type t) {
3438 ListBuffer<Type> buf = lb();
3439 for (Type sup : closure(t)) {
3440 if (sup.tag == TYPEVAR) {
3441 buf.append(sup);
3442 } else {
3443 buf.append(erasure(sup));
3444 }
3445 }
3446 return buf.toList();
3447 }
3448
3449 private Type arraySuperType = null;
3450 private Type arraySuperType() {
3451 // initialized lazily to avoid problems during compiler startup
3452 if (arraySuperType == null) {
3453 synchronized (this) {
3454 if (arraySuperType == null) {
3455 // JLS 10.8: all arrays implement Cloneable and Serializable.
3456 arraySuperType = makeCompoundType(List.of(syms.serializableType,
3457 syms.cloneableType), true);
3458 }
3459 }
3460 }
3461 return arraySuperType;
3462 }
3463 // </editor-fold>
3464
3465 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
3466 public Type glb(List<Type> ts) {
3467 Type t1 = ts.head;
3468 for (Type t2 : ts.tail) {
3469 if (t1.isErroneous())
3470 return t1;
3471 t1 = glb(t1, t2);
3472 }
3473 return t1;
3474 }
3475 //where
3476 public Type glb(Type t, Type s) {
3477 if (s == null)
3478 return t;
3479 else if (t.isPrimitive() || s.isPrimitive())
3480 return syms.errType;
3481 else if (isSubtypeNoCapture(t, s))
3482 return t;
3483 else if (isSubtypeNoCapture(s, t))
3484 return s;
3485
3486 List<Type> closure = union(closure(t), closure(s));
3487 List<Type> bounds = closureMin(closure);
3488
3489 if (bounds.isEmpty()) { // length == 0
3490 return syms.objectType;
3491 } else if (bounds.tail.isEmpty()) { // length == 1
3492 return bounds.head;
3493 } else { // length > 1
3494 int classCount = 0;
3495 for (Type bound : bounds)
3496 if (!bound.isInterface())
3497 classCount++;
3498 if (classCount > 1)
3499 return createErrorType(t);
3500 }
3501 return makeCompoundType(bounds);
3502 }
3503 // </editor-fold>
3504
3505 // <editor-fold defaultstate="collapsed" desc="hashCode">
3506 /**
3507 * Compute a hash code on a type.
3508 */
3509 public int hashCode(Type t) {
3510 return hashCode.visit(t);
3511 }
3512 // where
3513 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
3514
3515 public Integer visitType(Type t, Void ignored) {
3516 return t.tag.ordinal();
3517 }
3518
3519 @Override
3520 public Integer visitClassType(ClassType t, Void ignored) {
3521 int result = visit(t.getEnclosingType());
3522 result *= 127;
3523 result += t.tsym.flatName().hashCode();
3524 for (Type s : t.getTypeArguments()) {
3525 result *= 127;
3526 result += visit(s);
3527 }
3528 return result;
3529 }
3530
3531 @Override
3532 public Integer visitMethodType(MethodType t, Void ignored) {
3533 int h = METHOD.ordinal();
3534 for (List<Type> thisargs = t.argtypes;
3535 thisargs.tail != null;
3536 thisargs = thisargs.tail)
3537 h = (h << 5) + visit(thisargs.head);
3538 return (h << 5) + visit(t.restype);
3539 }
3540
3541 @Override
3542 public Integer visitWildcardType(WildcardType t, Void ignored) {
3543 int result = t.kind.hashCode();
3544 if (t.type != null) {
3545 result *= 127;
3546 result += visit(t.type);
3547 }
3548 return result;
3549 }
3550
3551 @Override
3552 public Integer visitArrayType(ArrayType t, Void ignored) {
3553 return visit(t.elemtype) + 12;
3554 }
3555
3556 @Override
3557 public Integer visitTypeVar(TypeVar t, Void ignored) {
3558 return System.identityHashCode(t.tsym);
3559 }
3560
3561 @Override
3562 public Integer visitUndetVar(UndetVar t, Void ignored) {
3563 return System.identityHashCode(t);
3564 }
3565
3566 @Override
3567 public Integer visitErrorType(ErrorType t, Void ignored) {
3568 return 0;
3569 }
3570 };
3571 // </editor-fold>
3572
3573 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
3574 /**
3575 * Does t have a result that is a subtype of the result type of s,
3576 * suitable for covariant returns? It is assumed that both types
3577 * are (possibly polymorphic) method types. Monomorphic method
3578 * types are handled in the obvious way. Polymorphic method types
3579 * require renaming all type variables of one to corresponding
3580 * type variables in the other, where correspondence is by
3581 * position in the type parameter list. */
3582 public boolean resultSubtype(Type t, Type s, Warner warner) {
3583 List<Type> tvars = t.getTypeArguments();
3584 List<Type> svars = s.getTypeArguments();
3585 Type tres = t.getReturnType();
3586 Type sres = subst(s.getReturnType(), svars, tvars);
3587 return covariantReturnType(tres, sres, warner);
3588 }
3589
3590 /**
3591 * Return-Type-Substitutable.
3592 * @jls section 8.4.5
3593 */
3594 public boolean returnTypeSubstitutable(Type r1, Type r2) {
3595 if (hasSameArgs(r1, r2))
3596 return resultSubtype(r1, r2, noWarnings);
3597 else
3598 return covariantReturnType(r1.getReturnType(),
3599 erasure(r2.getReturnType()),
3600 noWarnings);
3601 }
3602
3603 public boolean returnTypeSubstitutable(Type r1,
3604 Type r2, Type r2res,
3605 Warner warner) {
3606 if (isSameType(r1.getReturnType(), r2res))
3607 return true;
3608 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
3609 return false;
3610
3611 if (hasSameArgs(r1, r2))
3612 return covariantReturnType(r1.getReturnType(), r2res, warner);
3613 if (!allowCovariantReturns)
3614 return false;
3615 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
3616 return true;
3617 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
3618 return false;
3619 warner.warn(LintCategory.UNCHECKED);
3620 return true;
3621 }
3622
3623 /**
3624 * Is t an appropriate return type in an overrider for a
3625 * method that returns s?
3626 */
3627 public boolean covariantReturnType(Type t, Type s, Warner warner) {
3628 return
3629 isSameType(t, s) ||
3630 allowCovariantReturns &&
3631 !t.isPrimitive() &&
3632 !s.isPrimitive() &&
3633 isAssignable(t, s, warner);
3634 }
3635 // </editor-fold>
3636
3637 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
3638 /**
3639 * Return the class that boxes the given primitive.
3640 */
3641 public ClassSymbol boxedClass(Type t) {
3642 return reader.enterClass(syms.boxedName[t.tag.ordinal()]);
3643 }
3644
3645 /**
3646 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
3647 */
3648 public Type boxedTypeOrType(Type t) {
3649 return t.isPrimitive() ?
3650 boxedClass(t).type :
3651 t;
3652 }
3653
3654 /**
3655 * Return the primitive type corresponding to a boxed type.
3656 */
3657 public Type unboxedType(Type t) {
3658 if (allowBoxing) {
3659 for (int i=0; i<syms.boxedName.length; i++) {
3660 Name box = syms.boxedName[i];
3661 if (box != null &&
3662 asSuper(t, reader.enterClass(box)) != null)
3663 return syms.typeOfTag[i];
3664 }
3665 }
3666 return Type.noType;
3667 }
3668
3669 /**
3670 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
3671 */
3672 public Type unboxedTypeOrType(Type t) {
3673 Type unboxedType = unboxedType(t);
3674 return unboxedType.tag == NONE ? t : unboxedType;
3675 }
3676 // </editor-fold>
3677
3678 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3679 /*
3680 * JLS 5.1.10 Capture Conversion:
3681 *
3682 * Let G name a generic type declaration with n formal type
3683 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3684 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3685 * where, for 1 <= i <= n:
3686 *
3687 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3688 * Si is a fresh type variable whose upper bound is
3689 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3690 * type.
3691 *
3692 * + If Ti is a wildcard type argument of the form ? extends Bi,
3693 * then Si is a fresh type variable whose upper bound is
3694 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3695 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3696 * a compile-time error if for any two classes (not interfaces)
3697 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3698 *
3699 * + If Ti is a wildcard type argument of the form ? super Bi,
3700 * then Si is a fresh type variable whose upper bound is
3701 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3702 *
3703 * + Otherwise, Si = Ti.
3704 *
3705 * Capture conversion on any type other than a parameterized type
3706 * (4.5) acts as an identity conversion (5.1.1). Capture
3707 * conversions never require a special action at run time and
3708 * therefore never throw an exception at run time.
3709 *
3710 * Capture conversion is not applied recursively.
3711 */
3712 /**
3713 * Capture conversion as specified by the JLS.
3714 */
3715
3716 public List<Type> capture(List<Type> ts) {
3717 List<Type> buf = List.nil();
3718 for (Type t : ts) {
3719 buf = buf.prepend(capture(t));
3720 }
3721 return buf.reverse();
3722 }
3723 public Type capture(Type t) {
3724 if (t.tag != CLASS)
3725 return t;
3726 if (t.getEnclosingType() != Type.noType) {
3727 Type capturedEncl = capture(t.getEnclosingType());
3728 if (capturedEncl != t.getEnclosingType()) {
3729 Type type1 = memberType(capturedEncl, t.tsym);
3730 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3731 }
3732 }
3733 t = t.unannotatedType();
3734 ClassType cls = (ClassType)t;
3735 if (cls.isRaw() || !cls.isParameterized())
3736 return cls;
3737
3738 ClassType G = (ClassType)cls.asElement().asType();
3739 List<Type> A = G.getTypeArguments();
3740 List<Type> T = cls.getTypeArguments();
3741 List<Type> S = freshTypeVariables(T);
3742
3743 List<Type> currentA = A;
3744 List<Type> currentT = T;
3745 List<Type> currentS = S;
3746 boolean captured = false;
3747 while (!currentA.isEmpty() &&
3748 !currentT.isEmpty() &&
3749 !currentS.isEmpty()) {
3750 if (currentS.head != currentT.head) {
3751 captured = true;
3752 WildcardType Ti = (WildcardType)currentT.head.unannotatedType();
3753 Type Ui = currentA.head.getUpperBound();
3754 CapturedType Si = (CapturedType)currentS.head.unannotatedType();
3755 if (Ui == null)
3756 Ui = syms.objectType;
3757 switch (Ti.kind) {
3758 case UNBOUND:
3759 Si.bound = subst(Ui, A, S);
3760 Si.lower = syms.botType;
3761 break;
3762 case EXTENDS:
3763 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3764 Si.lower = syms.botType;
3765 break;
3766 case SUPER:
3767 Si.bound = subst(Ui, A, S);
3768 Si.lower = Ti.getSuperBound();
3769 break;
3770 }
3771 if (Si.bound == Si.lower)
3772 currentS.head = Si.bound;
3773 }
3774 currentA = currentA.tail;
3775 currentT = currentT.tail;
3776 currentS = currentS.tail;
3777 }
3778 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3779 return erasure(t); // some "rare" type involved
3780
3781 if (captured)
3782 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3783 else
3784 return t;
3785 }
3786 // where
3787 public List<Type> freshTypeVariables(List<Type> types) {
3788 ListBuffer<Type> result = lb();
3789 for (Type t : types) {
3790 if (t.tag == WILDCARD) {
3791 t = t.unannotatedType();
3792 Type bound = ((WildcardType)t).getExtendsBound();
3793 if (bound == null)
3794 bound = syms.objectType;
3795 result.append(new CapturedType(capturedName,
3796 syms.noSymbol,
3797 bound,
3798 syms.botType,
3799 (WildcardType)t));
3800 } else {
3801 result.append(t);
3802 }
3803 }
3804 return result.toList();
3805 }
3806 // </editor-fold>
3807
3808 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3809 private List<Type> upperBounds(List<Type> ss) {
3810 if (ss.isEmpty()) return ss;
3811 Type head = upperBound(ss.head);
3812 List<Type> tail = upperBounds(ss.tail);
3813 if (head != ss.head || tail != ss.tail)
3814 return tail.prepend(head);
3815 else
3816 return ss;
3817 }
3818
3819 private boolean sideCast(Type from, Type to, Warner warn) {
3820 // We are casting from type $from$ to type $to$, which are
3821 // non-final unrelated types. This method
3822 // tries to reject a cast by transferring type parameters
3823 // from $to$ to $from$ by common superinterfaces.
3824 boolean reverse = false;
3825 Type target = to;
3826 if ((to.tsym.flags() & INTERFACE) == 0) {
3827 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3828 reverse = true;
3829 to = from;
3830 from = target;
3831 }
3832 List<Type> commonSupers = superClosure(to, erasure(from));
3833 boolean giveWarning = commonSupers.isEmpty();
3834 // The arguments to the supers could be unified here to
3835 // get a more accurate analysis
3836 while (commonSupers.nonEmpty()) {
3837 Type t1 = asSuper(from, commonSupers.head.tsym);
3838 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3839 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3840 return false;
3841 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3842 commonSupers = commonSupers.tail;
3843 }
3844 if (giveWarning && !isReifiable(reverse ? from : to))
3845 warn.warn(LintCategory.UNCHECKED);
3846 if (!allowCovariantReturns)
3847 // reject if there is a common method signature with
3848 // incompatible return types.
3849 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3850 return true;
3851 }
3852
3853 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3854 // We are casting from type $from$ to type $to$, which are
3855 // unrelated types one of which is final and the other of
3856 // which is an interface. This method
3857 // tries to reject a cast by transferring type parameters
3858 // from the final class to the interface.
3859 boolean reverse = false;
3860 Type target = to;
3861 if ((to.tsym.flags() & INTERFACE) == 0) {
3862 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3863 reverse = true;
3864 to = from;
3865 from = target;
3866 }
3867 Assert.check((from.tsym.flags() & FINAL) != 0);
3868 Type t1 = asSuper(from, to.tsym);
3869 if (t1 == null) return false;
3870 Type t2 = to;
3871 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3872 return false;
3873 if (!allowCovariantReturns)
3874 // reject if there is a common method signature with
3875 // incompatible return types.
3876 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3877 if (!isReifiable(target) &&
3878 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3879 warn.warn(LintCategory.UNCHECKED);
3880 return true;
3881 }
3882
3883 private boolean giveWarning(Type from, Type to) {
3884 List<Type> bounds = to.isCompound() ?
3885 ((IntersectionClassType)to.unannotatedType()).getComponents() : List.of(to);
3886 for (Type b : bounds) {
3887 Type subFrom = asSub(from, b.tsym);
3888 if (b.isParameterized() &&
3889 (!(isUnbounded(b) ||
3890 isSubtype(from, b) ||
3891 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
3892 return true;
3893 }
3894 }
3895 return false;
3896 }
3897
3898 private List<Type> superClosure(Type t, Type s) {
3899 List<Type> cl = List.nil();
3900 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3901 if (isSubtype(s, erasure(l.head))) {
3902 cl = insert(cl, l.head);
3903 } else {
3904 cl = union(cl, superClosure(l.head, s));
3905 }
3906 }
3907 return cl;
3908 }
3909
3910 private boolean containsTypeEquivalent(Type t, Type s) {
3911 return
3912 isSameType(t, s) || // shortcut
3913 containsType(t, s) && containsType(s, t);
3914 }
3915
3916 // <editor-fold defaultstate="collapsed" desc="adapt">
3917 /**
3918 * Adapt a type by computing a substitution which maps a source
3919 * type to a target type.
3920 *
3921 * @param source the source type
3922 * @param target the target type
3923 * @param from the type variables of the computed substitution
3924 * @param to the types of the computed substitution.
3925 */
3926 public void adapt(Type source,
3927 Type target,
3928 ListBuffer<Type> from,
3929 ListBuffer<Type> to) throws AdaptFailure {
3930 new Adapter(from, to).adapt(source, target);
3931 }
3932
3933 class Adapter extends SimpleVisitor<Void, Type> {
3934
3935 ListBuffer<Type> from;
3936 ListBuffer<Type> to;
3937 Map<Symbol,Type> mapping;
3938
3939 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3940 this.from = from;
3941 this.to = to;
3942 mapping = new HashMap<Symbol,Type>();
3943 }
3944
3945 public void adapt(Type source, Type target) throws AdaptFailure {
3946 visit(source, target);
3947 List<Type> fromList = from.toList();
3948 List<Type> toList = to.toList();
3949 while (!fromList.isEmpty()) {
3950 Type val = mapping.get(fromList.head.tsym);
3951 if (toList.head != val)
3952 toList.head = val;
3953 fromList = fromList.tail;
3954 toList = toList.tail;
3955 }
3956 }
3957
3958 @Override
3959 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3960 if (target.tag == CLASS)
3961 adaptRecursive(source.allparams(), target.allparams());
3962 return null;
3963 }
3964
3965 @Override
3966 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3967 if (target.tag == ARRAY)
3968 adaptRecursive(elemtype(source), elemtype(target));
3969 return null;
3970 }
3971
3972 @Override
3973 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3974 if (source.isExtendsBound())
3975 adaptRecursive(upperBound(source), upperBound(target));
3976 else if (source.isSuperBound())
3977 adaptRecursive(lowerBound(source), lowerBound(target));
3978 return null;
3979 }
3980
3981 @Override
3982 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3983 // Check to see if there is
3984 // already a mapping for $source$, in which case
3985 // the old mapping will be merged with the new
3986 Type val = mapping.get(source.tsym);
3987 if (val != null) {
3988 if (val.isSuperBound() && target.isSuperBound()) {
3989 val = isSubtype(lowerBound(val), lowerBound(target))
3990 ? target : val;
3991 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3992 val = isSubtype(upperBound(val), upperBound(target))
3993 ? val : target;
3994 } else if (!isSameType(val, target)) {
3995 throw new AdaptFailure();
3996 }
3997 } else {
3998 val = target;
3999 from.append(source);
4000 to.append(target);
4001 }
4002 mapping.put(source.tsym, val);
4003 return null;
4004 }
4005
4006 @Override
4007 public Void visitType(Type source, Type target) {
4008 return null;
4009 }
4010
4011 private Set<TypePair> cache = new HashSet<TypePair>();
4012
4013 private void adaptRecursive(Type source, Type target) {
4014 TypePair pair = new TypePair(source, target);
4015 if (cache.add(pair)) {
4016 try {
4017 visit(source, target);
4018 } finally {
4019 cache.remove(pair);
4020 }
4021 }
4022 }
4023
4024 private void adaptRecursive(List<Type> source, List<Type> target) {
4025 if (source.length() == target.length()) {
4026 while (source.nonEmpty()) {
4027 adaptRecursive(source.head, target.head);
4028 source = source.tail;
4029 target = target.tail;
4030 }
4031 }
4032 }
4033 }
4034
4035 public static class AdaptFailure extends RuntimeException {
4036 static final long serialVersionUID = -7490231548272701566L;
4037 }
4038
4039 private void adaptSelf(Type t,
4040 ListBuffer<Type> from,
4041 ListBuffer<Type> to) {
4042 try {
4043 //if (t.tsym.type != t)
4044 adapt(t.tsym.type, t, from, to);
4045 } catch (AdaptFailure ex) {
4046 // Adapt should never fail calculating a mapping from
4047 // t.tsym.type to t as there can be no merge problem.
4048 throw new AssertionError(ex);
4049 }
4050 }
4051 // </editor-fold>
4052
4053 /**
4054 * Rewrite all type variables (universal quantifiers) in the given
4055 * type to wildcards (existential quantifiers). This is used to
4056 * determine if a cast is allowed. For example, if high is true
4057 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4058 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4059 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4060 * List<Integer>} with a warning.
4061 * @param t a type
4062 * @param high if true return an upper bound; otherwise a lower
4063 * bound
4064 * @param rewriteTypeVars only rewrite captured wildcards if false;
4065 * otherwise rewrite all type variables
4066 * @return the type rewritten with wildcards (existential
4067 * quantifiers) only
4068 */
4069 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4070 return new Rewriter(high, rewriteTypeVars).visit(t);
4071 }
4072
4073 class Rewriter extends UnaryVisitor<Type> {
4074
4075 boolean high;
4076 boolean rewriteTypeVars;
4077
4078 Rewriter(boolean high, boolean rewriteTypeVars) {
4079 this.high = high;
4080 this.rewriteTypeVars = rewriteTypeVars;
4081 }
4082
4083 @Override
4084 public Type visitClassType(ClassType t, Void s) {
4085 ListBuffer<Type> rewritten = new ListBuffer<Type>();
4086 boolean changed = false;
4087 for (Type arg : t.allparams()) {
4088 Type bound = visit(arg);
4089 if (arg != bound) {
4090 changed = true;
4091 }
4092 rewritten.append(bound);
4093 }
4094 if (changed)
4095 return subst(t.tsym.type,
4096 t.tsym.type.allparams(),
4097 rewritten.toList());
4098 else
4099 return t;
4100 }
4101
4102 public Type visitType(Type t, Void s) {
4103 return high ? upperBound(t) : lowerBound(t);
4104 }
4105
4106 @Override
4107 public Type visitCapturedType(CapturedType t, Void s) {
4108 Type w_bound = t.wildcard.type;
4109 Type bound = w_bound.contains(t) ?
4110 erasure(w_bound) :
4111 visit(w_bound);
4112 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4113 }
4114
4115 @Override
4116 public Type visitTypeVar(TypeVar t, Void s) {
4117 if (rewriteTypeVars) {
4118 Type bound = t.bound.contains(t) ?
4119 erasure(t.bound) :
4120 visit(t.bound);
4121 return rewriteAsWildcardType(bound, t, EXTENDS);
4122 } else {
4123 return t;
4124 }
4125 }
4126
4127 @Override
4128 public Type visitWildcardType(WildcardType t, Void s) {
4129 Type bound2 = visit(t.type);
4130 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4131 }
4132
4133 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4134 switch (bk) {
4135 case EXTENDS: return high ?
4136 makeExtendsWildcard(B(bound), formal) :
4137 makeExtendsWildcard(syms.objectType, formal);
4138 case SUPER: return high ?
4139 makeSuperWildcard(syms.botType, formal) :
4140 makeSuperWildcard(B(bound), formal);
4141 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4142 default:
4143 Assert.error("Invalid bound kind " + bk);
4144 return null;
4145 }
4146 }
4147
4148 Type B(Type t) {
4149 while (t.tag == WILDCARD) {
4150 WildcardType w = (WildcardType)t.unannotatedType();
4151 t = high ?
4152 w.getExtendsBound() :
4153 w.getSuperBound();
4154 if (t == null) {
4155 t = high ? syms.objectType : syms.botType;
4156 }
4157 }
4158 return t;
4159 }
4160 }
4161
4162
4163 /**
4164 * Create a wildcard with the given upper (extends) bound; create
4165 * an unbounded wildcard if bound is Object.
4166 *
4167 * @param bound the upper bound
4168 * @param formal the formal type parameter that will be
4169 * substituted by the wildcard
4170 */
4171 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4172 if (bound == syms.objectType) {
4173 return new WildcardType(syms.objectType,
4174 BoundKind.UNBOUND,
4175 syms.boundClass,
4176 formal);
4177 } else {
4178 return new WildcardType(bound,
4179 BoundKind.EXTENDS,
4180 syms.boundClass,
4181 formal);
4182 }
4183 }
4184
4185 /**
4186 * Create a wildcard with the given lower (super) bound; create an
4187 * unbounded wildcard if bound is bottom (type of {@code null}).
4188 *
4189 * @param bound the lower bound
4190 * @param formal the formal type parameter that will be
4191 * substituted by the wildcard
4192 */
4193 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4194 if (bound.tag == BOT) {
4195 return new WildcardType(syms.objectType,
4196 BoundKind.UNBOUND,
4197 syms.boundClass,
4198 formal);
4199 } else {
4200 return new WildcardType(bound,
4201 BoundKind.SUPER,
4202 syms.boundClass,
4203 formal);
4204 }
4205 }
4206
4207 /**
4208 * A wrapper for a type that allows use in sets.
4209 */
4210 public static class UniqueType {
4211 public final Type type;
4212 final Types types;
4213
4214 public UniqueType(Type type, Types types) {
4215 this.type = type;
4216 this.types = types;
4217 }
4218
4219 public int hashCode() {
4220 return types.hashCode(type);
4221 }
4222
4223 public boolean equals(Object obj) {
4224 return (obj instanceof UniqueType) &&
4225 types.isSameAnnotatedType(type, ((UniqueType)obj).type);
4226 }
4227
4228 public String toString() {
4229 return type.toString();
4230 }
4231
4232 }
4233 // </editor-fold>
4234
4235 // <editor-fold defaultstate="collapsed" desc="Visitors">
4236 /**
4237 * A default visitor for types. All visitor methods except
4238 * visitType are implemented by delegating to visitType. Concrete
4239 * subclasses must provide an implementation of visitType and can
4240 * override other methods as needed.
4241 *
4242 * @param <R> the return type of the operation implemented by this
4243 * visitor; use Void if no return type is needed.
4244 * @param <S> the type of the second argument (the first being the
4245 * type itself) of the operation implemented by this visitor; use
4246 * Void if a second argument is not needed.
4247 */
4248 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4249 final public R visit(Type t, S s) { return t.accept(this, s); }
4250 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4251 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4252 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4253 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4254 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4255 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4256 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4257 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4258 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4259 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4260 // Pretend annotations don't exist
4261 public R visitAnnotatedType(AnnotatedType t, S s) { return visit(t.underlyingType, s); }
4262 }
4263
4264 /**
4265 * A default visitor for symbols. All visitor methods except
4266 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4267 * subclasses must provide an implementation of visitSymbol and can
4268 * override other methods as needed.
4269 *
4270 * @param <R> the return type of the operation implemented by this
4271 * visitor; use Void if no return type is needed.
4272 * @param <S> the type of the second argument (the first being the
4273 * symbol itself) of the operation implemented by this visitor; use
4274 * Void if a second argument is not needed.
4275 */
4276 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4277 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
4278 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4279 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4280 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4281 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4282 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4283 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4284 }
4285
4286 /**
4287 * A <em>simple</em> visitor for types. This visitor is simple as
4288 * captured wildcards, for-all types (generic methods), and
4289 * undetermined type variables (part of inference) are hidden.
4290 * Captured wildcards are hidden by treating them as type
4291 * variables and the rest are hidden by visiting their qtypes.
4292 *
4293 * @param <R> the return type of the operation implemented by this
4294 * visitor; use Void if no return type is needed.
4295 * @param <S> the type of the second argument (the first being the
4296 * type itself) of the operation implemented by this visitor; use
4297 * Void if a second argument is not needed.
4298 */
4299 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4300 @Override
4301 public R visitCapturedType(CapturedType t, S s) {
4302 return visitTypeVar(t, s);
4303 }
4304 @Override
4305 public R visitForAll(ForAll t, S s) {
4306 return visit(t.qtype, s);
4307 }
4308 @Override
4309 public R visitUndetVar(UndetVar t, S s) {
4310 return visit(t.qtype, s);
4311 }
4312 }
4313
4314 /**
4315 * A plain relation on types. That is a 2-ary function on the
4316 * form Type × Type → Boolean.
4317 * <!-- In plain text: Type x Type -> Boolean -->
4318 */
4319 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4320
4321 /**
4322 * A convenience visitor for implementing operations that only
4323 * require one argument (the type itself), that is, unary
4324 * operations.
4325 *
4326 * @param <R> the return type of the operation implemented by this
4327 * visitor; use Void if no return type is needed.
4328 */
4329 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4330 final public R visit(Type t) { return t.accept(this, null); }
4331 }
4332
4333 /**
4334 * A visitor for implementing a mapping from types to types. The
4335 * default behavior of this class is to implement the identity
4336 * mapping (mapping a type to itself). This can be overridden in
4337 * subclasses.
4338 *
4339 * @param <S> the type of the second argument (the first being the
4340 * type itself) of this mapping; use Void if a second argument is
4341 * not needed.
4342 */
4343 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4344 final public Type visit(Type t) { return t.accept(this, null); }
4345 public Type visitType(Type t, S s) { return t; }
4346 }
4347 // </editor-fold>
4348
4349
4350 // <editor-fold defaultstate="collapsed" desc="Annotation support">
4351
4352 public RetentionPolicy getRetention(Attribute.Compound a) {
4353 return getRetention(a.type.tsym);
4354 }
4355
4356 public RetentionPolicy getRetention(Symbol sym) {
4357 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
4358 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
4359 if (c != null) {
4360 Attribute value = c.member(names.value);
4361 if (value != null && value instanceof Attribute.Enum) {
4362 Name levelName = ((Attribute.Enum)value).value.name;
4363 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
4364 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
4365 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
4366 else ;// /* fail soft */ throw new AssertionError(levelName);
4367 }
4368 }
4369 return vis;
4370 }
4371 // </editor-fold>
4372
4373 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
4374
4375 public static abstract class SignatureGenerator {
4376
4377 private final Types types;
4378
4379 protected abstract void append(char ch);
4380 protected abstract void append(byte[] ba);
4381 protected abstract void append(Name name);
4382 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
4383
4384 protected SignatureGenerator(Types types) {
4385 this.types = types;
4386 }
4387
4388 /**
4389 * Assemble signature of given type in string buffer.
4390 */
4391 public void assembleSig(Type type) {
4392 type = type.unannotatedType();
4393 switch (type.getTag()) {
4394 case BYTE:
4395 append('B');
4396 break;
4397 case SHORT:
4398 append('S');
4399 break;
4400 case CHAR:
4401 append('C');
4402 break;
4403 case INT:
4404 append('I');
4405 break;
4406 case LONG:
4407 append('J');
4408 break;
4409 case FLOAT:
4410 append('F');
4411 break;
4412 case DOUBLE:
4413 append('D');
4414 break;
4415 case BOOLEAN:
4416 append('Z');
4417 break;
4418 case VOID:
4419 append('V');
4420 break;
4421 case CLASS:
4422 append('L');
4423 assembleClassSig(type);
4424 append(';');
4425 break;
4426 case ARRAY:
4427 ArrayType at = (ArrayType) type;
4428 append('[');
4429 assembleSig(at.elemtype);
4430 break;
4431 case METHOD:
4432 MethodType mt = (MethodType) type;
4433 append('(');
4434 assembleSig(mt.argtypes);
4435 append(')');
4436 assembleSig(mt.restype);
4437 if (hasTypeVar(mt.thrown)) {
4438 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
4439 append('^');
4440 assembleSig(l.head);
4441 }
4442 }
4443 break;
4444 case WILDCARD: {
4445 Type.WildcardType ta = (Type.WildcardType) type;
4446 switch (ta.kind) {
4447 case SUPER:
4448 append('-');
4449 assembleSig(ta.type);
4450 break;
4451 case EXTENDS:
4452 append('+');
4453 assembleSig(ta.type);
4454 break;
4455 case UNBOUND:
4456 append('*');
4457 break;
4458 default:
4459 throw new AssertionError(ta.kind);
4460 }
4461 break;
4462 }
4463 case TYPEVAR:
4464 append('T');
4465 append(type.tsym.name);
4466 append(';');
4467 break;
4468 case FORALL:
4469 Type.ForAll ft = (Type.ForAll) type;
4470 assembleParamsSig(ft.tvars);
4471 assembleSig(ft.qtype);
4472 break;
4473 default:
4474 throw new AssertionError("typeSig " + type.getTag());
4475 }
4476 }
4477
4478 public boolean hasTypeVar(List<Type> l) {
4479 while (l.nonEmpty()) {
4480 if (l.head.hasTag(TypeTag.TYPEVAR)) {
4481 return true;
4482 }
4483 l = l.tail;
4484 }
4485 return false;
4486 }
4487
4488 public void assembleClassSig(Type type) {
4489 type = type.unannotatedType();
4490 ClassType ct = (ClassType) type;
4491 ClassSymbol c = (ClassSymbol) ct.tsym;
4492 classReference(c);
4493 Type outer = ct.getEnclosingType();
4494 if (outer.allparams().nonEmpty()) {
4495 boolean rawOuter =
4496 c.owner.kind == Kinds.MTH || // either a local class
4497 c.name == types.names.empty; // or anonymous
4498 assembleClassSig(rawOuter
4499 ? types.erasure(outer)
4500 : outer);
4501 append('.');
4502 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
4503 append(rawOuter
4504 ? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength())
4505 : c.name);
4506 } else {
4507 append(externalize(c.flatname));
4508 }
4509 if (ct.getTypeArguments().nonEmpty()) {
4510 append('<');
4511 assembleSig(ct.getTypeArguments());
4512 append('>');
4513 }
4514 }
4515
4516 public void assembleParamsSig(List<Type> typarams) {
4517 append('<');
4518 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
4519 Type.TypeVar tvar = (Type.TypeVar) ts.head;
4520 append(tvar.tsym.name);
4521 List<Type> bounds = types.getBounds(tvar);
4522 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
4523 append(':');
4524 }
4525 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
4526 append(':');
4527 assembleSig(l.head);
4528 }
4529 }
4530 append('>');
4531 }
4532
4533 private void assembleSig(List<Type> types) {
4534 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
4535 assembleSig(ts.head);
4536 }
4537 }
4538 }
4539 // </editor-fold>
4540 }