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 // <editor-fold defaultstate="collapsed" desc="isCastable">
1321 public boolean isCastable(Type t, Type s) {
1322 return isCastable(t, s, noWarnings);
1323 }
1324
1325 /**
1326 * Is t is castable to s?<br>
1327 * s is assumed to be an erased type.<br>
1328 * (not defined for Method and ForAll types).
1329 */
1330 public boolean isCastable(Type t, Type s, Warner warn) {
1331 if (t == s)
1332 return true;
1333
1334 if (t.isPrimitive() != s.isPrimitive())
1335 return allowBoxing && (
1336 isConvertible(t, s, warn)
1337 || (allowObjectToPrimitiveCast &&
1338 s.isPrimitive() &&
1339 isSubtype(boxedClass(s).type, t)));
1340 if (warn != warnStack.head) {
1341 try {
1342 warnStack = warnStack.prepend(warn);
1343 checkUnsafeVarargsConversion(t, s, warn);
1344 return isCastable.visit(t,s);
1345 } finally {
1346 warnStack = warnStack.tail;
1347 }
1348 } else {
1349 return isCastable.visit(t,s);
1350 }
1351 }
1352 // where
1353 private TypeRelation isCastable = new TypeRelation() {
1354
1355 public Boolean visitType(Type t, Type s) {
1356 if (s.tag == ERROR)
1357 return true;
1358
1359 switch (t.tag) {
1360 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1361 case DOUBLE:
1362 return s.isNumeric();
1363 case BOOLEAN:
1364 return s.tag == BOOLEAN;
1365 case VOID:
1366 return false;
1367 case BOT:
1368 return isSubtype(t, s);
1369 default:
1370 throw new AssertionError();
1371 }
1372 }
1373
1374 @Override
1375 public Boolean visitWildcardType(WildcardType t, Type s) {
1376 return isCastable(upperBound(t), s, warnStack.head);
1377 }
1378
1379 @Override
1380 public Boolean visitClassType(ClassType t, Type s) {
1381 if (s.tag == ERROR || s.tag == BOT)
1382 return true;
1383
1384 if (s.tag == TYPEVAR) {
1385 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1386 warnStack.head.warn(LintCategory.UNCHECKED);
1387 return true;
1388 } else {
1389 return false;
1390 }
1391 }
1392
1393 if (t.isCompound() || s.isCompound()) {
1394 return !t.isCompound() ?
1395 visitIntersectionType((IntersectionClassType)s.unannotatedType(), t, true) :
1396 visitIntersectionType((IntersectionClassType)t.unannotatedType(), s, false);
1397 }
1398
1399 if (s.tag == CLASS || s.tag == ARRAY) {
1400 boolean upcast;
1401 if ((upcast = isSubtype(erasure(t), erasure(s)))
1402 || isSubtype(erasure(s), erasure(t))) {
1403 if (!upcast && s.tag == ARRAY) {
1404 if (!isReifiable(s))
1405 warnStack.head.warn(LintCategory.UNCHECKED);
1406 return true;
1407 } else if (s.isRaw()) {
1408 return true;
1409 } else if (t.isRaw()) {
1410 if (!isUnbounded(s))
1411 warnStack.head.warn(LintCategory.UNCHECKED);
1412 return true;
1413 }
1414 // Assume |a| <: |b|
1415 final Type a = upcast ? t : s;
1416 final Type b = upcast ? s : t;
1417 final boolean HIGH = true;
1418 final boolean LOW = false;
1419 final boolean DONT_REWRITE_TYPEVARS = false;
1420 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1421 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1422 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1423 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1424 Type lowSub = asSub(bLow, aLow.tsym);
1425 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1426 if (highSub == null) {
1427 final boolean REWRITE_TYPEVARS = true;
1428 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1429 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1430 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1431 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1432 lowSub = asSub(bLow, aLow.tsym);
1433 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1434 }
1435 if (highSub != null) {
1436 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1437 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1438 }
1439 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1440 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1441 && !disjointTypes(aLow.allparams(), highSub.allparams())
1442 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1443 if (upcast ? giveWarning(a, b) :
1444 giveWarning(b, a))
1445 warnStack.head.warn(LintCategory.UNCHECKED);
1446 return true;
1447 }
1448 }
1449 if (isReifiable(s))
1450 return isSubtypeUnchecked(a, b);
1451 else
1452 return isSubtypeUnchecked(a, b, warnStack.head);
1453 }
1454
1455 // Sidecast
1456 if (s.tag == CLASS) {
1457 if ((s.tsym.flags() & INTERFACE) != 0) {
1458 return ((t.tsym.flags() & FINAL) == 0)
1459 ? sideCast(t, s, warnStack.head)
1460 : sideCastFinal(t, s, warnStack.head);
1461 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1462 return ((s.tsym.flags() & FINAL) == 0)
1463 ? sideCast(t, s, warnStack.head)
1464 : sideCastFinal(t, s, warnStack.head);
1465 } else {
1466 // unrelated class types
1467 return false;
1468 }
1469 }
1470 }
1471 return false;
1472 }
1473
1474 boolean visitIntersectionType(IntersectionClassType ict, Type s, boolean reverse) {
1475 Warner warn = noWarnings;
1476 for (Type c : ict.getComponents()) {
1477 warn.clear();
1478 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
1479 return false;
1480 }
1481 if (warn.hasLint(LintCategory.UNCHECKED))
1482 warnStack.head.warn(LintCategory.UNCHECKED);
1483 return true;
1484 }
1485
1486 @Override
1487 public Boolean visitArrayType(ArrayType t, Type s) {
1488 switch (s.tag) {
1489 case ERROR:
1490 case BOT:
1491 return true;
1492 case TYPEVAR:
1493 if (isCastable(s, t, noWarnings)) {
1494 warnStack.head.warn(LintCategory.UNCHECKED);
1495 return true;
1496 } else {
1497 return false;
1498 }
1499 case CLASS:
1500 return isSubtype(t, s);
1501 case ARRAY:
1502 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1503 return elemtype(t).tag == elemtype(s).tag;
1504 } else {
1505 return visit(elemtype(t), elemtype(s));
1506 }
1507 default:
1508 return false;
1509 }
1510 }
1511
1512 @Override
1513 public Boolean visitTypeVar(TypeVar t, Type s) {
1514 switch (s.tag) {
1515 case ERROR:
1516 case BOT:
1517 return true;
1518 case TYPEVAR:
1519 if (isSubtype(t, s)) {
1520 return true;
1521 } else if (isCastable(t.bound, s, noWarnings)) {
1522 warnStack.head.warn(LintCategory.UNCHECKED);
1523 return true;
1524 } else {
1525 return false;
1526 }
1527 default:
1528 return isCastable(t.bound, s, warnStack.head);
1529 }
1530 }
1531
1532 @Override
1533 public Boolean visitErrorType(ErrorType t, Type s) {
1534 return true;
1535 }
1536 };
1537 // </editor-fold>
1538
1539 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1540 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1541 while (ts.tail != null && ss.tail != null) {
1542 if (disjointType(ts.head, ss.head)) return true;
1543 ts = ts.tail;
1544 ss = ss.tail;
1545 }
1546 return false;
1547 }
1548
1549 /**
1550 * Two types or wildcards are considered disjoint if it can be
1551 * proven that no type can be contained in both. It is
1552 * conservative in that it is allowed to say that two types are
1553 * not disjoint, even though they actually are.
1554 *
1555 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1556 * {@code X} and {@code Y} are not disjoint.
1557 */
1558 public boolean disjointType(Type t, Type s) {
1559 return disjointType.visit(t, s);
1560 }
1561 // where
1562 private TypeRelation disjointType = new TypeRelation() {
1563
1564 private Set<TypePair> cache = new HashSet<TypePair>();
1565
1566 public Boolean visitType(Type t, Type s) {
1567 if (s.tag == WILDCARD)
1568 return visit(s, t);
1569 else
1570 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1571 }
1572
1573 private boolean isCastableRecursive(Type t, Type s) {
1574 TypePair pair = new TypePair(t, s);
1575 if (cache.add(pair)) {
1576 try {
1577 return Types.this.isCastable(t, s);
1578 } finally {
1579 cache.remove(pair);
1580 }
1581 } else {
1582 return true;
1583 }
1584 }
1585
1586 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1587 TypePair pair = new TypePair(t, s);
1588 if (cache.add(pair)) {
1589 try {
1590 return Types.this.notSoftSubtype(t, s);
1591 } finally {
1592 cache.remove(pair);
1593 }
1594 } else {
1595 return false;
1596 }
1597 }
1598
1599 @Override
1600 public Boolean visitWildcardType(WildcardType t, Type s) {
1601 if (t.isUnbound())
1602 return false;
1603
1604 if (s.tag != WILDCARD) {
1605 if (t.isExtendsBound())
1606 return notSoftSubtypeRecursive(s, t.type);
1607 else // isSuperBound()
1608 return notSoftSubtypeRecursive(t.type, s);
1609 }
1610
1611 if (s.isUnbound())
1612 return false;
1613
1614 if (t.isExtendsBound()) {
1615 if (s.isExtendsBound())
1616 return !isCastableRecursive(t.type, upperBound(s));
1617 else if (s.isSuperBound())
1618 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1619 } else if (t.isSuperBound()) {
1620 if (s.isExtendsBound())
1621 return notSoftSubtypeRecursive(t.type, upperBound(s));
1622 }
1623 return false;
1624 }
1625 };
1626 // </editor-fold>
1627
1628 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1629 /**
1630 * Returns the lower bounds of the formals of a method.
1631 */
1632 public List<Type> lowerBoundArgtypes(Type t) {
1633 return lowerBounds(t.getParameterTypes());
1634 }
1635 public List<Type> lowerBounds(List<Type> ts) {
1636 return map(ts, lowerBoundMapping);
1637 }
1638 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1639 public Type apply(Type t) {
1640 return lowerBound(t);
1641 }
1642 };
1643 // </editor-fold>
1644
1645 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1646 /**
1647 * This relation answers the question: is impossible that
1648 * something of type `t' can be a subtype of `s'? This is
1649 * different from the question "is `t' not a subtype of `s'?"
1650 * when type variables are involved: Integer is not a subtype of T
1651 * where {@code <T extends Number>} but it is not true that Integer cannot
1652 * possibly be a subtype of T.
1653 */
1654 public boolean notSoftSubtype(Type t, Type s) {
1655 if (t == s) return false;
1656 if (t.tag == TYPEVAR) {
1657 TypeVar tv = (TypeVar) t;
1658 return !isCastable(tv.bound,
1659 relaxBound(s),
1660 noWarnings);
1661 }
1662 if (s.tag != WILDCARD)
1663 s = upperBound(s);
1664
1665 return !isSubtype(t, relaxBound(s));
1666 }
1667
1668 private Type relaxBound(Type t) {
1669 if (t.tag == TYPEVAR) {
1670 while (t.tag == TYPEVAR)
1671 t = t.getUpperBound();
1672 t = rewriteQuantifiers(t, true, true);
1673 }
1674 return t;
1675 }
1676 // </editor-fold>
1677
1678 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1679 public boolean isReifiable(Type t) {
1680 return isReifiable.visit(t);
1681 }
1682 // where
1683 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1684
1685 public Boolean visitType(Type t, Void ignored) {
1686 return true;
1687 }
1688
1689 @Override
1690 public Boolean visitClassType(ClassType t, Void ignored) {
1691 if (t.isCompound())
1692 return false;
1693 else {
1694 if (!t.isParameterized())
1695 return true;
1696
1697 for (Type param : t.allparams()) {
1698 if (!param.isUnbound())
1699 return false;
1700 }
1701 return true;
1702 }
1703 }
1704
1705 @Override
1706 public Boolean visitArrayType(ArrayType t, Void ignored) {
1707 return visit(t.elemtype);
1708 }
1709
1710 @Override
1711 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1712 return false;
1713 }
1714 };
1715 // </editor-fold>
1716
1717 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1718 public boolean isArray(Type t) {
1719 while (t.tag == WILDCARD)
1720 t = upperBound(t);
1721 return t.tag == ARRAY;
1722 }
1723
1724 /**
1725 * The element type of an array.
1726 */
1727 public Type elemtype(Type t) {
1728 switch (t.tag) {
1729 case WILDCARD:
1730 return elemtype(upperBound(t));
1731 case ARRAY:
1732 t = t.unannotatedType();
1733 return ((ArrayType)t).elemtype;
1734 case FORALL:
1735 return elemtype(((ForAll)t).qtype);
1736 case ERROR:
1737 return t;
1738 default:
1739 return null;
1740 }
1741 }
1742
1743 public Type elemtypeOrType(Type t) {
1744 Type elemtype = elemtype(t);
1745 return elemtype != null ?
1746 elemtype :
1747 t;
1748 }
1749
1750 /**
1751 * Mapping to take element type of an arraytype
1752 */
1753 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1754 public Type apply(Type t) { return elemtype(t); }
1755 };
1756
1757 /**
1758 * The number of dimensions of an array type.
1759 */
1760 public int dimensions(Type t) {
1761 int result = 0;
1762 while (t.tag == ARRAY) {
1763 result++;
1764 t = elemtype(t);
1765 }
1766 return result;
1767 }
1768
1769 /**
1770 * Returns an ArrayType with the component type t
1771 *
1772 * @param t The component type of the ArrayType
1773 * @return the ArrayType for the given component
1774 */
1775 public ArrayType makeArrayType(Type t) {
1776 if (t.tag == VOID ||
1777 t.tag == PACKAGE) {
1778 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
1779 }
1780 return new ArrayType(t, syms.arrayClass);
1781 }
1782 // </editor-fold>
1783
1784 // <editor-fold defaultstate="collapsed" desc="asSuper">
1785 /**
1786 * Return the (most specific) base type of t that starts with the
1787 * given symbol. If none exists, return null.
1788 *
1789 * @param t a type
1790 * @param sym a symbol
1791 */
1792 public Type asSuper(Type t, Symbol sym) {
1793 return asSuper.visit(t, sym);
1794 }
1795 // where
1796 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1797
1798 public Type visitType(Type t, Symbol sym) {
1799 return null;
1800 }
1801
1802 @Override
1803 public Type visitClassType(ClassType t, Symbol sym) {
1804 if (t.tsym == sym)
1805 return t;
1806
1807 Type st = supertype(t);
1808 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1809 Type x = asSuper(st, sym);
1810 if (x != null)
1811 return x;
1812 }
1813 if ((sym.flags() & INTERFACE) != 0) {
1814 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1815 Type x = asSuper(l.head, sym);
1816 if (x != null)
1817 return x;
1818 }
1819 }
1820 return null;
1821 }
1822
1823 @Override
1824 public Type visitArrayType(ArrayType t, Symbol sym) {
1825 return isSubtype(t, sym.type) ? sym.type : null;
1826 }
1827
1828 @Override
1829 public Type visitTypeVar(TypeVar t, Symbol sym) {
1830 if (t.tsym == sym)
1831 return t;
1832 else
1833 return asSuper(t.bound, sym);
1834 }
1835
1836 @Override
1837 public Type visitErrorType(ErrorType t, Symbol sym) {
1838 return t;
1839 }
1840 };
1841
1842 /**
1843 * Return the base type of t or any of its outer types that starts
1844 * with the given symbol. If none exists, return null.
1845 *
1846 * @param t a type
1847 * @param sym a symbol
1848 */
1849 public Type asOuterSuper(Type t, Symbol sym) {
1850 switch (t.tag) {
1851 case CLASS:
1852 do {
1853 Type s = asSuper(t, sym);
1854 if (s != null) return s;
1855 t = t.getEnclosingType();
1856 } while (t.tag == CLASS);
1857 return null;
1858 case ARRAY:
1859 return isSubtype(t, sym.type) ? sym.type : null;
1860 case TYPEVAR:
1861 return asSuper(t, sym);
1862 case ERROR:
1863 return t;
1864 default:
1865 return null;
1866 }
1867 }
1868
1869 /**
1870 * Return the base type of t or any of its enclosing types that
1871 * starts with the given symbol. If none exists, return null.
1872 *
1873 * @param t a type
1874 * @param sym a symbol
1875 */
1876 public Type asEnclosingSuper(Type t, Symbol sym) {
1877 switch (t.tag) {
1878 case CLASS:
1879 do {
1880 Type s = asSuper(t, sym);
1881 if (s != null) return s;
1882 Type outer = t.getEnclosingType();
1883 t = (outer.tag == CLASS) ? outer :
1884 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1885 Type.noType;
1886 } while (t.tag == CLASS);
1887 return null;
1888 case ARRAY:
1889 return isSubtype(t, sym.type) ? sym.type : null;
1890 case TYPEVAR:
1891 return asSuper(t, sym);
1892 case ERROR:
1893 return t;
1894 default:
1895 return null;
1896 }
1897 }
1898 // </editor-fold>
1899
1900 // <editor-fold defaultstate="collapsed" desc="memberType">
1901 /**
1902 * The type of given symbol, seen as a member of t.
1903 *
1904 * @param t a type
1905 * @param sym a symbol
1906 */
1907 public Type memberType(Type t, Symbol sym) {
1908 return (sym.flags() & STATIC) != 0
1909 ? sym.type
1910 : memberType.visit(t, sym);
1911 }
1912 // where
1913 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1914
1915 public Type visitType(Type t, Symbol sym) {
1916 return sym.type;
1917 }
1918
1919 @Override
1920 public Type visitWildcardType(WildcardType t, Symbol sym) {
1921 return memberType(upperBound(t), sym);
1922 }
1923
1924 @Override
1925 public Type visitClassType(ClassType t, Symbol sym) {
1926 Symbol owner = sym.owner;
1927 long flags = sym.flags();
1928 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1929 Type base = asOuterSuper(t, owner);
1930 //if t is an intersection type T = CT & I1 & I2 ... & In
1931 //its supertypes CT, I1, ... In might contain wildcards
1932 //so we need to go through capture conversion
1933 base = t.isCompound() ? capture(base) : base;
1934 if (base != null) {
1935 List<Type> ownerParams = owner.type.allparams();
1936 List<Type> baseParams = base.allparams();
1937 if (ownerParams.nonEmpty()) {
1938 if (baseParams.isEmpty()) {
1939 // then base is a raw type
1940 return erasure(sym.type);
1941 } else {
1942 return subst(sym.type, ownerParams, baseParams);
1943 }
1944 }
1945 }
1946 }
1947 return sym.type;
1948 }
1949
1950 @Override
1951 public Type visitTypeVar(TypeVar t, Symbol sym) {
1952 return memberType(t.bound, sym);
1953 }
1954
1955 @Override
1956 public Type visitErrorType(ErrorType t, Symbol sym) {
1957 return t;
1958 }
1959 };
1960 // </editor-fold>
1961
1962 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1963 public boolean isAssignable(Type t, Type s) {
1964 return isAssignable(t, s, noWarnings);
1965 }
1966
1967 /**
1968 * Is t assignable to s?<br>
1969 * Equivalent to subtype except for constant values and raw
1970 * types.<br>
1971 * (not defined for Method and ForAll types)
1972 */
1973 public boolean isAssignable(Type t, Type s, Warner warn) {
1974 if (t.tag == ERROR)
1975 return true;
1976 if (t.tag.isSubRangeOf(INT) && t.constValue() != null) {
1977 int value = ((Number)t.constValue()).intValue();
1978 switch (s.tag) {
1979 case BYTE:
1980 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1981 return true;
1982 break;
1983 case CHAR:
1984 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1985 return true;
1986 break;
1987 case SHORT:
1988 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1989 return true;
1990 break;
1991 case INT:
1992 return true;
1993 case CLASS:
1994 switch (unboxedType(s).tag) {
1995 case BYTE:
1996 case CHAR:
1997 case SHORT:
1998 return isAssignable(t, unboxedType(s), warn);
1999 }
2000 break;
2001 }
2002 }
2003 return isConvertible(t, s, warn);
2004 }
2005 // </editor-fold>
2006
2007 // <editor-fold defaultstate="collapsed" desc="erasure">
2008 /**
2009 * The erasure of t {@code |t|} -- the type that results when all
2010 * type parameters in t are deleted.
2011 */
2012 public Type erasure(Type t) {
2013 return eraseNotNeeded(t)? t : erasure(t, false);
2014 }
2015 //where
2016 private boolean eraseNotNeeded(Type t) {
2017 // We don't want to erase primitive types and String type as that
2018 // operation is idempotent. Also, erasing these could result in loss
2019 // of information such as constant values attached to such types.
2020 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2021 }
2022
2023 private Type erasure(Type t, boolean recurse) {
2024 if (t.isPrimitive())
2025 return t; /* fast special case */
2026 else
2027 return erasure.visit(t, recurse);
2028 }
2029 // where
2030 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
2031 public Type visitType(Type t, Boolean recurse) {
2032 if (t.isPrimitive())
2033 return t; /*fast special case*/
2034 else
2035 return t.map(recurse ? erasureRecFun : erasureFun);
2036 }
2037
2038 @Override
2039 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2040 return erasure(upperBound(t), recurse);
2041 }
2042
2043 @Override
2044 public Type visitClassType(ClassType t, Boolean recurse) {
2045 Type erased = t.tsym.erasure(Types.this);
2046 if (recurse) {
2047 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
2048 }
2049 return erased;
2050 }
2051
2052 @Override
2053 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2054 return erasure(t.bound, recurse);
2055 }
2056
2057 @Override
2058 public Type visitErrorType(ErrorType t, Boolean recurse) {
2059 return t;
2060 }
2061
2062 @Override
2063 public Type visitAnnotatedType(AnnotatedType t, Boolean recurse) {
2064 Type erased = erasure(t.underlyingType, recurse);
2065 if (erased.isAnnotated()) {
2066 // This can only happen when the underlying type is a
2067 // type variable and the upper bound of it is annotated.
2068 // The annotation on the type variable overrides the one
2069 // on the bound.
2070 erased = ((AnnotatedType)erased).underlyingType;
2071 }
2072 return new AnnotatedType(t.typeAnnotations, erased);
2073 }
2074 };
2075
2076 private Mapping erasureFun = new Mapping ("erasure") {
2077 public Type apply(Type t) { return erasure(t); }
2078 };
2079
2080 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
2081 public Type apply(Type t) { return erasureRecursive(t); }
2082 };
2083
2084 public List<Type> erasure(List<Type> ts) {
2085 return Type.map(ts, erasureFun);
2086 }
2087
2088 public Type erasureRecursive(Type t) {
2089 return erasure(t, true);
2090 }
2091
2092 public List<Type> erasureRecursive(List<Type> ts) {
2093 return Type.map(ts, erasureRecFun);
2094 }
2095 // </editor-fold>
2096
2097 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
2098 /**
2099 * Make a compound type from non-empty list of types
2100 *
2101 * @param bounds the types from which the compound type is formed
2102 * @param supertype is objectType if all bounds are interfaces,
2103 * null otherwise.
2104 */
2105 public Type makeCompoundType(List<Type> bounds) {
2106 return makeCompoundType(bounds, bounds.head.tsym.isInterface());
2107 }
2108 public Type makeCompoundType(List<Type> bounds, boolean allInterfaces) {
2109 Assert.check(bounds.nonEmpty());
2110 Type firstExplicitBound = bounds.head;
2111 if (allInterfaces) {
2112 bounds = bounds.prepend(syms.objectType);
2113 }
2114 ClassSymbol bc =
2115 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2116 Type.moreInfo
2117 ? names.fromString(bounds.toString())
2118 : names.empty,
2119 null,
2120 syms.noSymbol);
2121 bc.type = new IntersectionClassType(bounds, bc, allInterfaces);
2122 bc.erasure_field = (bounds.head.tag == TYPEVAR) ?
2123 syms.objectType : // error condition, recover
2124 erasure(firstExplicitBound);
2125 bc.members_field = new Scope(bc);
2126 return bc.type;
2127 }
2128
2129 /**
2130 * A convenience wrapper for {@link #makeCompoundType(List)}; the
2131 * arguments are converted to a list and passed to the other
2132 * method. Note that this might cause a symbol completion.
2133 * Hence, this version of makeCompoundType may not be called
2134 * during a classfile read.
2135 */
2136 public Type makeCompoundType(Type bound1, Type bound2) {
2137 return makeCompoundType(List.of(bound1, bound2));
2138 }
2139 // </editor-fold>
2140
2141 // <editor-fold defaultstate="collapsed" desc="supertype">
2142 public Type supertype(Type t) {
2143 return supertype.visit(t);
2144 }
2145 // where
2146 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2147
2148 public Type visitType(Type t, Void ignored) {
2149 // A note on wildcards: there is no good way to
2150 // determine a supertype for a super bounded wildcard.
2151 return null;
2152 }
2153
2154 @Override
2155 public Type visitClassType(ClassType t, Void ignored) {
2156 if (t.supertype_field == null) {
2157 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2158 // An interface has no superclass; its supertype is Object.
2159 if (t.isInterface())
2160 supertype = ((ClassType)t.tsym.type).supertype_field;
2161 if (t.supertype_field == null) {
2162 List<Type> actuals = classBound(t).allparams();
2163 List<Type> formals = t.tsym.type.allparams();
2164 if (t.hasErasedSupertypes()) {
2165 t.supertype_field = erasureRecursive(supertype);
2166 } else if (formals.nonEmpty()) {
2167 t.supertype_field = subst(supertype, formals, actuals);
2168 }
2169 else {
2170 t.supertype_field = supertype;
2171 }
2172 }
2173 }
2174 return t.supertype_field;
2175 }
2176
2177 /**
2178 * The supertype is always a class type. If the type
2179 * variable's bounds start with a class type, this is also
2180 * the supertype. Otherwise, the supertype is
2181 * java.lang.Object.
2182 */
2183 @Override
2184 public Type visitTypeVar(TypeVar t, Void ignored) {
2185 if (t.bound.tag == TYPEVAR ||
2186 (!t.bound.isCompound() && !t.bound.isInterface())) {
2187 return t.bound;
2188 } else {
2189 return supertype(t.bound);
2190 }
2191 }
2192
2193 @Override
2194 public Type visitArrayType(ArrayType t, Void ignored) {
2195 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2196 return arraySuperType();
2197 else
2198 return new ArrayType(supertype(t.elemtype), t.tsym);
2199 }
2200
2201 @Override
2202 public Type visitErrorType(ErrorType t, Void ignored) {
2203 return t;
2204 }
2205 };
2206 // </editor-fold>
2207
2208 // <editor-fold defaultstate="collapsed" desc="interfaces">
2209 /**
2210 * Return the interfaces implemented by this class.
2211 */
2212 public List<Type> interfaces(Type t) {
2213 return interfaces.visit(t);
2214 }
2215 // where
2216 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2217
2218 public List<Type> visitType(Type t, Void ignored) {
2219 return List.nil();
2220 }
2221
2222 @Override
2223 public List<Type> visitClassType(ClassType t, Void ignored) {
2224 if (t.interfaces_field == null) {
2225 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2226 if (t.interfaces_field == null) {
2227 // If t.interfaces_field is null, then t must
2228 // be a parameterized type (not to be confused
2229 // with a generic type declaration).
2230 // Terminology:
2231 // Parameterized type: List<String>
2232 // Generic type declaration: class List<E> { ... }
2233 // So t corresponds to List<String> and
2234 // t.tsym.type corresponds to List<E>.
2235 // The reason t must be parameterized type is
2236 // that completion will happen as a side
2237 // effect of calling
2238 // ClassSymbol.getInterfaces. Since
2239 // t.interfaces_field is null after
2240 // completion, we can assume that t is not the
2241 // type of a class/interface declaration.
2242 Assert.check(t != t.tsym.type, t);
2243 List<Type> actuals = t.allparams();
2244 List<Type> formals = t.tsym.type.allparams();
2245 if (t.hasErasedSupertypes()) {
2246 t.interfaces_field = erasureRecursive(interfaces);
2247 } else if (formals.nonEmpty()) {
2248 t.interfaces_field =
2249 upperBounds(subst(interfaces, formals, actuals));
2250 }
2251 else {
2252 t.interfaces_field = interfaces;
2253 }
2254 }
2255 }
2256 return t.interfaces_field;
2257 }
2258
2259 @Override
2260 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2261 if (t.bound.isCompound())
2262 return interfaces(t.bound);
2263
2264 if (t.bound.isInterface())
2265 return List.of(t.bound);
2266
2267 return List.nil();
2268 }
2269 };
2270
2271 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2272 for (Type i2 : interfaces(origin.type)) {
2273 if (isym == i2.tsym) return true;
2274 }
2275 return false;
2276 }
2277 // </editor-fold>
2278
2279 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2280 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
2281
2282 public boolean isDerivedRaw(Type t) {
2283 Boolean result = isDerivedRawCache.get(t);
2284 if (result == null) {
2285 result = isDerivedRawInternal(t);
2286 isDerivedRawCache.put(t, result);
2287 }
2288 return result;
2289 }
2290
2291 public boolean isDerivedRawInternal(Type t) {
2292 if (t.isErroneous())
2293 return false;
2294 return
2295 t.isRaw() ||
2296 supertype(t) != null && isDerivedRaw(supertype(t)) ||
2297 isDerivedRaw(interfaces(t));
2298 }
2299
2300 public boolean isDerivedRaw(List<Type> ts) {
2301 List<Type> l = ts;
2302 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2303 return l.nonEmpty();
2304 }
2305 // </editor-fold>
2306
2307 // <editor-fold defaultstate="collapsed" desc="setBounds">
2308 /**
2309 * Set the bounds field of the given type variable to reflect a
2310 * (possibly multiple) list of bounds.
2311 * @param t a type variable
2312 * @param bounds the bounds, must be nonempty
2313 * @param supertype is objectType if all bounds are interfaces,
2314 * null otherwise.
2315 */
2316 public void setBounds(TypeVar t, List<Type> bounds) {
2317 setBounds(t, bounds, bounds.head.tsym.isInterface());
2318 }
2319
2320 /**
2321 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
2322 * third parameter is computed directly, as follows: if all
2323 * all bounds are interface types, the computed supertype is Object,
2324 * otherwise the supertype is simply left null (in this case, the supertype
2325 * is assumed to be the head of the bound list passed as second argument).
2326 * Note that this check might cause a symbol completion. Hence, this version of
2327 * setBounds may not be called during a classfile read.
2328 */
2329 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2330 t.bound = bounds.tail.isEmpty() ?
2331 bounds.head :
2332 makeCompoundType(bounds, allInterfaces);
2333 t.rank_field = -1;
2334 }
2335 // </editor-fold>
2336
2337 // <editor-fold defaultstate="collapsed" desc="getBounds">
2338 /**
2339 * Return list of bounds of the given type variable.
2340 */
2341 public List<Type> getBounds(TypeVar t) {
2342 if (t.bound.hasTag(NONE))
2343 return List.nil();
2344 else if (t.bound.isErroneous() || !t.bound.isCompound())
2345 return List.of(t.bound);
2346 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2347 return interfaces(t).prepend(supertype(t));
2348 else
2349 // No superclass was given in bounds.
2350 // In this case, supertype is Object, erasure is first interface.
2351 return interfaces(t);
2352 }
2353 // </editor-fold>
2354
2355 // <editor-fold defaultstate="collapsed" desc="classBound">
2356 /**
2357 * If the given type is a (possibly selected) type variable,
2358 * return the bounding class of this type, otherwise return the
2359 * type itself.
2360 */
2361 public Type classBound(Type t) {
2362 return classBound.visit(t);
2363 }
2364 // where
2365 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2366
2367 public Type visitType(Type t, Void ignored) {
2368 return t;
2369 }
2370
2371 @Override
2372 public Type visitClassType(ClassType t, Void ignored) {
2373 Type outer1 = classBound(t.getEnclosingType());
2374 if (outer1 != t.getEnclosingType())
2375 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
2376 else
2377 return t;
2378 }
2379
2380 @Override
2381 public Type visitTypeVar(TypeVar t, Void ignored) {
2382 return classBound(supertype(t));
2383 }
2384
2385 @Override
2386 public Type visitErrorType(ErrorType t, Void ignored) {
2387 return t;
2388 }
2389 };
2390 // </editor-fold>
2391
2392 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
2393 /**
2394 * Returns true iff the first signature is a <em>sub
2395 * signature</em> of the other. This is <b>not</b> an equivalence
2396 * relation.
2397 *
2398 * @jls section 8.4.2.
2399 * @see #overrideEquivalent(Type t, Type s)
2400 * @param t first signature (possibly raw).
2401 * @param s second signature (could be subjected to erasure).
2402 * @return true if t is a sub signature of s.
2403 */
2404 public boolean isSubSignature(Type t, Type s) {
2405 return isSubSignature(t, s, true);
2406 }
2407
2408 public boolean isSubSignature(Type t, Type s, boolean strict) {
2409 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2410 }
2411
2412 /**
2413 * Returns true iff these signatures are related by <em>override
2414 * equivalence</em>. This is the natural extension of
2415 * isSubSignature to an equivalence relation.
2416 *
2417 * @jls section 8.4.2.
2418 * @see #isSubSignature(Type t, Type s)
2419 * @param t a signature (possible raw, could be subjected to
2420 * erasure).
2421 * @param s a signature (possible raw, could be subjected to
2422 * erasure).
2423 * @return true if either argument is a sub signature of the other.
2424 */
2425 public boolean overrideEquivalent(Type t, Type s) {
2426 return hasSameArgs(t, s) ||
2427 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2428 }
2429
2430 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2431 for (Scope.Entry e = syms.objectType.tsym.members().lookup(msym.name) ; e.scope != null ; e = e.next()) {
2432 if (msym.overrides(e.sym, origin, Types.this, true)) {
2433 return true;
2434 }
2435 }
2436 return false;
2437 }
2438
2439 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2440 class ImplementationCache {
2441
2442 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
2443 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
2444
2445 class Entry {
2446 final MethodSymbol cachedImpl;
2447 final Filter<Symbol> implFilter;
2448 final boolean checkResult;
2449 final int prevMark;
2450
2451 public Entry(MethodSymbol cachedImpl,
2452 Filter<Symbol> scopeFilter,
2453 boolean checkResult,
2454 int prevMark) {
2455 this.cachedImpl = cachedImpl;
2456 this.implFilter = scopeFilter;
2457 this.checkResult = checkResult;
2458 this.prevMark = prevMark;
2459 }
2460
2461 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
2462 return this.implFilter == scopeFilter &&
2463 this.checkResult == checkResult &&
2464 this.prevMark == mark;
2465 }
2466 }
2467
2468 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2469 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2470 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2471 if (cache == null) {
2472 cache = new HashMap<TypeSymbol, Entry>();
2473 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2474 }
2475 Entry e = cache.get(origin);
2476 CompoundScope members = membersClosure(origin.type, true);
2477 if (e == null ||
2478 !e.matches(implFilter, checkResult, members.getMark())) {
2479 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2480 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2481 return impl;
2482 }
2483 else {
2484 return e.cachedImpl;
2485 }
2486 }
2487
2488 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2489 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = supertype(t)) {
2490 while (t.tag == TYPEVAR)
2491 t = t.getUpperBound();
2492 TypeSymbol c = t.tsym;
2493 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2494 e.scope != null;
2495 e = e.next(implFilter)) {
2496 if (e.sym != null &&
2497 e.sym.overrides(ms, origin, Types.this, checkResult))
2498 return (MethodSymbol)e.sym;
2499 }
2500 }
2501 return null;
2502 }
2503 }
2504
2505 private ImplementationCache implCache = new ImplementationCache();
2506
2507 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2508 return implCache.get(ms, origin, checkResult, implFilter);
2509 }
2510 // </editor-fold>
2511
2512 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2513 class MembersClosureCache extends SimpleVisitor<CompoundScope, Boolean> {
2514
2515 private WeakHashMap<TypeSymbol, Entry> _map =
2516 new WeakHashMap<TypeSymbol, Entry>();
2517
2518 class Entry {
2519 final boolean skipInterfaces;
2520 final CompoundScope compoundScope;
2521
2522 public Entry(boolean skipInterfaces, CompoundScope compoundScope) {
2523 this.skipInterfaces = skipInterfaces;
2524 this.compoundScope = compoundScope;
2525 }
2526
2527 boolean matches(boolean skipInterfaces) {
2528 return this.skipInterfaces == skipInterfaces;
2529 }
2530 }
2531
2532 List<TypeSymbol> seenTypes = List.nil();
2533
2534 /** members closure visitor methods **/
2535
2536 public CompoundScope visitType(Type t, Boolean skipInterface) {
2537 return null;
2538 }
2539
2540 @Override
2541 public CompoundScope visitClassType(ClassType t, Boolean skipInterface) {
2542 if (seenTypes.contains(t.tsym)) {
2543 //this is possible when an interface is implemented in multiple
2544 //superclasses, or when a classs hierarchy is circular - in such
2545 //cases we don't need to recurse (empty scope is returned)
2546 return new CompoundScope(t.tsym);
2547 }
2548 try {
2549 seenTypes = seenTypes.prepend(t.tsym);
2550 ClassSymbol csym = (ClassSymbol)t.tsym;
2551 Entry e = _map.get(csym);
2552 if (e == null || !e.matches(skipInterface)) {
2553 CompoundScope membersClosure = new CompoundScope(csym);
2554 if (!skipInterface) {
2555 for (Type i : interfaces(t)) {
2556 membersClosure.addSubScope(visit(i, skipInterface));
2557 }
2558 }
2559 membersClosure.addSubScope(visit(supertype(t), skipInterface));
2560 membersClosure.addSubScope(csym.members());
2561 e = new Entry(skipInterface, membersClosure);
2562 _map.put(csym, e);
2563 }
2564 return e.compoundScope;
2565 }
2566 finally {
2567 seenTypes = seenTypes.tail;
2568 }
2569 }
2570
2571 @Override
2572 public CompoundScope visitTypeVar(TypeVar t, Boolean skipInterface) {
2573 return visit(t.getUpperBound(), skipInterface);
2574 }
2575 }
2576
2577 private MembersClosureCache membersCache = new MembersClosureCache();
2578
2579 public CompoundScope membersClosure(Type site, boolean skipInterface) {
2580 return membersCache.visit(site, skipInterface);
2581 }
2582 // </editor-fold>
2583
2584
2585 //where
2586 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
2587 Filter<Symbol> filter = new MethodFilter(ms, site);
2588 List<MethodSymbol> candidates = List.nil();
2589 for (Symbol s : membersClosure(site, false).getElements(filter)) {
2590 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
2591 return List.of((MethodSymbol)s);
2592 } else if (!candidates.contains(s)) {
2593 candidates = candidates.prepend((MethodSymbol)s);
2594 }
2595 }
2596 return prune(candidates);
2597 }
2598
2599 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
2600 ListBuffer<MethodSymbol> methodsMin = ListBuffer.lb();
2601 for (MethodSymbol m1 : methods) {
2602 boolean isMin_m1 = true;
2603 for (MethodSymbol m2 : methods) {
2604 if (m1 == m2) continue;
2605 if (m2.owner != m1.owner &&
2606 asSuper(m2.owner.type, m1.owner) != null) {
2607 isMin_m1 = false;
2608 break;
2609 }
2610 }
2611 if (isMin_m1)
2612 methodsMin.append(m1);
2613 }
2614 return methodsMin.toList();
2615 }
2616 // where
2617 private class MethodFilter implements Filter<Symbol> {
2618
2619 Symbol msym;
2620 Type site;
2621
2622 MethodFilter(Symbol msym, Type site) {
2623 this.msym = msym;
2624 this.site = site;
2625 }
2626
2627 public boolean accepts(Symbol s) {
2628 return s.kind == Kinds.MTH &&
2629 s.name == msym.name &&
2630 s.isInheritedIn(site.tsym, Types.this) &&
2631 overrideEquivalent(memberType(site, s), memberType(site, msym));
2632 }
2633 };
2634 // </editor-fold>
2635
2636 /**
2637 * Does t have the same arguments as s? It is assumed that both
2638 * types are (possibly polymorphic) method types. Monomorphic
2639 * method types "have the same arguments", if their argument lists
2640 * are equal. Polymorphic method types "have the same arguments",
2641 * if they have the same arguments after renaming all type
2642 * variables of one to corresponding type variables in the other,
2643 * where correspondence is by position in the type parameter list.
2644 */
2645 public boolean hasSameArgs(Type t, Type s) {
2646 return hasSameArgs(t, s, true);
2647 }
2648
2649 public boolean hasSameArgs(Type t, Type s, boolean strict) {
2650 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
2651 }
2652
2653 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
2654 return hasSameArgs.visit(t, s);
2655 }
2656 // where
2657 private class HasSameArgs extends TypeRelation {
2658
2659 boolean strict;
2660
2661 public HasSameArgs(boolean strict) {
2662 this.strict = strict;
2663 }
2664
2665 public Boolean visitType(Type t, Type s) {
2666 throw new AssertionError();
2667 }
2668
2669 @Override
2670 public Boolean visitMethodType(MethodType t, Type s) {
2671 return s.tag == METHOD
2672 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2673 }
2674
2675 @Override
2676 public Boolean visitForAll(ForAll t, Type s) {
2677 if (s.tag != FORALL)
2678 return strict ? false : visitMethodType(t.asMethodType(), s);
2679
2680 ForAll forAll = (ForAll)s;
2681 return hasSameBounds(t, forAll)
2682 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2683 }
2684
2685 @Override
2686 public Boolean visitErrorType(ErrorType t, Type s) {
2687 return false;
2688 }
2689 };
2690
2691 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
2692 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
2693
2694 // </editor-fold>
2695
2696 // <editor-fold defaultstate="collapsed" desc="subst">
2697 public List<Type> subst(List<Type> ts,
2698 List<Type> from,
2699 List<Type> to) {
2700 return new Subst(from, to).subst(ts);
2701 }
2702
2703 /**
2704 * Substitute all occurrences of a type in `from' with the
2705 * corresponding type in `to' in 't'. Match lists `from' and `to'
2706 * from the right: If lists have different length, discard leading
2707 * elements of the longer list.
2708 */
2709 public Type subst(Type t, List<Type> from, List<Type> to) {
2710 return new Subst(from, to).subst(t);
2711 }
2712
2713 private class Subst extends UnaryVisitor<Type> {
2714 List<Type> from;
2715 List<Type> to;
2716
2717 public Subst(List<Type> from, List<Type> to) {
2718 int fromLength = from.length();
2719 int toLength = to.length();
2720 while (fromLength > toLength) {
2721 fromLength--;
2722 from = from.tail;
2723 }
2724 while (fromLength < toLength) {
2725 toLength--;
2726 to = to.tail;
2727 }
2728 this.from = from;
2729 this.to = to;
2730 }
2731
2732 Type subst(Type t) {
2733 if (from.tail == null)
2734 return t;
2735 else
2736 return visit(t);
2737 }
2738
2739 List<Type> subst(List<Type> ts) {
2740 if (from.tail == null)
2741 return ts;
2742 boolean wild = false;
2743 if (ts.nonEmpty() && from.nonEmpty()) {
2744 Type head1 = subst(ts.head);
2745 List<Type> tail1 = subst(ts.tail);
2746 if (head1 != ts.head || tail1 != ts.tail)
2747 return tail1.prepend(head1);
2748 }
2749 return ts;
2750 }
2751
2752 public Type visitType(Type t, Void ignored) {
2753 return t;
2754 }
2755
2756 @Override
2757 public Type visitMethodType(MethodType t, Void ignored) {
2758 List<Type> argtypes = subst(t.argtypes);
2759 Type restype = subst(t.restype);
2760 List<Type> thrown = subst(t.thrown);
2761 if (argtypes == t.argtypes &&
2762 restype == t.restype &&
2763 thrown == t.thrown)
2764 return t;
2765 else
2766 return new MethodType(argtypes, restype, thrown, t.tsym);
2767 }
2768
2769 @Override
2770 public Type visitTypeVar(TypeVar t, Void ignored) {
2771 for (List<Type> from = this.from, to = this.to;
2772 from.nonEmpty();
2773 from = from.tail, to = to.tail) {
2774 if (t == from.head) {
2775 return to.head.withTypeVar(t);
2776 }
2777 }
2778 return t;
2779 }
2780
2781 @Override
2782 public Type visitClassType(ClassType t, Void ignored) {
2783 if (!t.isCompound()) {
2784 List<Type> typarams = t.getTypeArguments();
2785 List<Type> typarams1 = subst(typarams);
2786 Type outer = t.getEnclosingType();
2787 Type outer1 = subst(outer);
2788 if (typarams1 == typarams && outer1 == outer)
2789 return t;
2790 else
2791 return new ClassType(outer1, typarams1, t.tsym);
2792 } else {
2793 Type st = subst(supertype(t));
2794 List<Type> is = upperBounds(subst(interfaces(t)));
2795 if (st == supertype(t) && is == interfaces(t))
2796 return t;
2797 else
2798 return makeCompoundType(is.prepend(st));
2799 }
2800 }
2801
2802 @Override
2803 public Type visitWildcardType(WildcardType t, Void ignored) {
2804 Type bound = t.type;
2805 if (t.kind != BoundKind.UNBOUND)
2806 bound = subst(bound);
2807 if (bound == t.type) {
2808 return t;
2809 } else {
2810 if (t.isExtendsBound() && bound.isExtendsBound())
2811 bound = upperBound(bound);
2812 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2813 }
2814 }
2815
2816 @Override
2817 public Type visitArrayType(ArrayType t, Void ignored) {
2818 Type elemtype = subst(t.elemtype);
2819 if (elemtype == t.elemtype)
2820 return t;
2821 else
2822 return new ArrayType(upperBound(elemtype), t.tsym);
2823 }
2824
2825 @Override
2826 public Type visitForAll(ForAll t, Void ignored) {
2827 if (Type.containsAny(to, t.tvars)) {
2828 //perform alpha-renaming of free-variables in 't'
2829 //if 'to' types contain variables that are free in 't'
2830 List<Type> freevars = newInstances(t.tvars);
2831 t = new ForAll(freevars,
2832 Types.this.subst(t.qtype, t.tvars, freevars));
2833 }
2834 List<Type> tvars1 = substBounds(t.tvars, from, to);
2835 Type qtype1 = subst(t.qtype);
2836 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2837 return t;
2838 } else if (tvars1 == t.tvars) {
2839 return new ForAll(tvars1, qtype1);
2840 } else {
2841 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2842 }
2843 }
2844
2845 @Override
2846 public Type visitErrorType(ErrorType t, Void ignored) {
2847 return t;
2848 }
2849 }
2850
2851 public List<Type> substBounds(List<Type> tvars,
2852 List<Type> from,
2853 List<Type> to) {
2854 if (tvars.isEmpty())
2855 return tvars;
2856 ListBuffer<Type> newBoundsBuf = lb();
2857 boolean changed = false;
2858 // calculate new bounds
2859 for (Type t : tvars) {
2860 TypeVar tv = (TypeVar) t;
2861 Type bound = subst(tv.bound, from, to);
2862 if (bound != tv.bound)
2863 changed = true;
2864 newBoundsBuf.append(bound);
2865 }
2866 if (!changed)
2867 return tvars;
2868 ListBuffer<Type> newTvars = lb();
2869 // create new type variables without bounds
2870 for (Type t : tvars) {
2871 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2872 }
2873 // the new bounds should use the new type variables in place
2874 // of the old
2875 List<Type> newBounds = newBoundsBuf.toList();
2876 from = tvars;
2877 to = newTvars.toList();
2878 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2879 newBounds.head = subst(newBounds.head, from, to);
2880 }
2881 newBounds = newBoundsBuf.toList();
2882 // set the bounds of new type variables to the new bounds
2883 for (Type t : newTvars.toList()) {
2884 TypeVar tv = (TypeVar) t;
2885 tv.bound = newBounds.head;
2886 newBounds = newBounds.tail;
2887 }
2888 return newTvars.toList();
2889 }
2890
2891 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2892 Type bound1 = subst(t.bound, from, to);
2893 if (bound1 == t.bound)
2894 return t;
2895 else {
2896 // create new type variable without bounds
2897 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2898 // the new bound should use the new type variable in place
2899 // of the old
2900 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2901 return tv;
2902 }
2903 }
2904 // </editor-fold>
2905
2906 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2907 /**
2908 * Does t have the same bounds for quantified variables as s?
2909 */
2910 boolean hasSameBounds(ForAll t, ForAll s) {
2911 List<Type> l1 = t.tvars;
2912 List<Type> l2 = s.tvars;
2913 while (l1.nonEmpty() && l2.nonEmpty() &&
2914 isSameType(l1.head.getUpperBound(),
2915 subst(l2.head.getUpperBound(),
2916 s.tvars,
2917 t.tvars))) {
2918 l1 = l1.tail;
2919 l2 = l2.tail;
2920 }
2921 return l1.isEmpty() && l2.isEmpty();
2922 }
2923 // </editor-fold>
2924
2925 // <editor-fold defaultstate="collapsed" desc="newInstances">
2926 /** Create new vector of type variables from list of variables
2927 * changing all recursive bounds from old to new list.
2928 */
2929 public List<Type> newInstances(List<Type> tvars) {
2930 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2931 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2932 TypeVar tv = (TypeVar) l.head;
2933 tv.bound = subst(tv.bound, tvars, tvars1);
2934 }
2935 return tvars1;
2936 }
2937 private static final Mapping newInstanceFun = new Mapping("newInstanceFun") {
2938 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2939 };
2940 // </editor-fold>
2941
2942 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
2943 return original.accept(methodWithParameters, newParams);
2944 }
2945 // where
2946 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
2947 public Type visitType(Type t, List<Type> newParams) {
2948 throw new IllegalArgumentException("Not a method type: " + t);
2949 }
2950 public Type visitMethodType(MethodType t, List<Type> newParams) {
2951 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
2952 }
2953 public Type visitForAll(ForAll t, List<Type> newParams) {
2954 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
2955 }
2956 };
2957
2958 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
2959 return original.accept(methodWithThrown, newThrown);
2960 }
2961 // where
2962 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
2963 public Type visitType(Type t, List<Type> newThrown) {
2964 throw new IllegalArgumentException("Not a method type: " + t);
2965 }
2966 public Type visitMethodType(MethodType t, List<Type> newThrown) {
2967 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
2968 }
2969 public Type visitForAll(ForAll t, List<Type> newThrown) {
2970 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
2971 }
2972 };
2973
2974 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
2975 return original.accept(methodWithReturn, newReturn);
2976 }
2977 // where
2978 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
2979 public Type visitType(Type t, Type newReturn) {
2980 throw new IllegalArgumentException("Not a method type: " + t);
2981 }
2982 public Type visitMethodType(MethodType t, Type newReturn) {
2983 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym);
2984 }
2985 public Type visitForAll(ForAll t, Type newReturn) {
2986 return new ForAll(t.tvars, t.qtype.accept(this, newReturn));
2987 }
2988 };
2989
2990 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2991 public Type createErrorType(Type originalType) {
2992 return new ErrorType(originalType, syms.errSymbol);
2993 }
2994
2995 public Type createErrorType(ClassSymbol c, Type originalType) {
2996 return new ErrorType(c, originalType);
2997 }
2998
2999 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3000 return new ErrorType(name, container, originalType);
3001 }
3002 // </editor-fold>
3003
3004 // <editor-fold defaultstate="collapsed" desc="rank">
3005 /**
3006 * The rank of a class is the length of the longest path between
3007 * the class and java.lang.Object in the class inheritance
3008 * graph. Undefined for all but reference types.
3009 */
3010 public int rank(Type t) {
3011 t = t.unannotatedType();
3012 switch(t.tag) {
3013 case CLASS: {
3014 ClassType cls = (ClassType)t;
3015 if (cls.rank_field < 0) {
3016 Name fullname = cls.tsym.getQualifiedName();
3017 if (fullname == names.java_lang_Object)
3018 cls.rank_field = 0;
3019 else {
3020 int r = rank(supertype(cls));
3021 for (List<Type> l = interfaces(cls);
3022 l.nonEmpty();
3023 l = l.tail) {
3024 if (rank(l.head) > r)
3025 r = rank(l.head);
3026 }
3027 cls.rank_field = r + 1;
3028 }
3029 }
3030 return cls.rank_field;
3031 }
3032 case TYPEVAR: {
3033 TypeVar tvar = (TypeVar)t;
3034 if (tvar.rank_field < 0) {
3035 int r = rank(supertype(tvar));
3036 for (List<Type> l = interfaces(tvar);
3037 l.nonEmpty();
3038 l = l.tail) {
3039 if (rank(l.head) > r) r = rank(l.head);
3040 }
3041 tvar.rank_field = r + 1;
3042 }
3043 return tvar.rank_field;
3044 }
3045 case ERROR:
3046 return 0;
3047 default:
3048 throw new AssertionError();
3049 }
3050 }
3051 // </editor-fold>
3052
3053 /**
3054 * Helper method for generating a string representation of a given type
3055 * accordingly to a given locale
3056 */
3057 public String toString(Type t, Locale locale) {
3058 return Printer.createStandardPrinter(messages).visit(t, locale);
3059 }
3060
3061 /**
3062 * Helper method for generating a string representation of a given type
3063 * accordingly to a given locale
3064 */
3065 public String toString(Symbol t, Locale locale) {
3066 return Printer.createStandardPrinter(messages).visit(t, locale);
3067 }
3068
3069 // <editor-fold defaultstate="collapsed" desc="toString">
3070 /**
3071 * This toString is slightly more descriptive than the one on Type.
3072 *
3073 * @deprecated Types.toString(Type t, Locale l) provides better support
3074 * for localization
3075 */
3076 @Deprecated
3077 public String toString(Type t) {
3078 if (t.tag == FORALL) {
3079 ForAll forAll = (ForAll)t;
3080 return typaramsString(forAll.tvars) + forAll.qtype;
3081 }
3082 return "" + t;
3083 }
3084 // where
3085 private String typaramsString(List<Type> tvars) {
3086 StringBuilder s = new StringBuilder();
3087 s.append('<');
3088 boolean first = true;
3089 for (Type t : tvars) {
3090 if (!first) s.append(", ");
3091 first = false;
3092 appendTyparamString(((TypeVar)t.unannotatedType()), s);
3093 }
3094 s.append('>');
3095 return s.toString();
3096 }
3097 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3098 buf.append(t);
3099 if (t.bound == null ||
3100 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
3101 return;
3102 buf.append(" extends "); // Java syntax; no need for i18n
3103 Type bound = t.bound;
3104 if (!bound.isCompound()) {
3105 buf.append(bound);
3106 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3107 buf.append(supertype(t));
3108 for (Type intf : interfaces(t)) {
3109 buf.append('&');
3110 buf.append(intf);
3111 }
3112 } else {
3113 // No superclass was given in bounds.
3114 // In this case, supertype is Object, erasure is first interface.
3115 boolean first = true;
3116 for (Type intf : interfaces(t)) {
3117 if (!first) buf.append('&');
3118 first = false;
3119 buf.append(intf);
3120 }
3121 }
3122 }
3123 // </editor-fold>
3124
3125 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3126 /**
3127 * A cache for closures.
3128 *
3129 * <p>A closure is a list of all the supertypes and interfaces of
3130 * a class or interface type, ordered by ClassSymbol.precedes
3131 * (that is, subclasses come first, arbitrary but fixed
3132 * otherwise).
3133 */
3134 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
3135
3136 /**
3137 * Returns the closure of a class or interface type.
3138 */
3139 public List<Type> closure(Type t) {
3140 List<Type> cl = closureCache.get(t);
3141 if (cl == null) {
3142 Type st = supertype(t);
3143 if (!t.isCompound()) {
3144 if (st.tag == CLASS) {
3145 cl = insert(closure(st), t);
3146 } else if (st.tag == TYPEVAR) {
3147 cl = closure(st).prepend(t);
3148 } else {
3149 cl = List.of(t);
3150 }
3151 } else {
3152 cl = closure(supertype(t));
3153 }
3154 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3155 cl = union(cl, closure(l.head));
3156 closureCache.put(t, cl);
3157 }
3158 return cl;
3159 }
3160
3161 /**
3162 * Insert a type in a closure
3163 */
3164 public List<Type> insert(List<Type> cl, Type t) {
3165 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
3166 return cl.prepend(t);
3167 } else if (cl.head.tsym.precedes(t.tsym, this)) {
3168 return insert(cl.tail, t).prepend(cl.head);
3169 } else {
3170 return cl;
3171 }
3172 }
3173
3174 /**
3175 * Form the union of two closures
3176 */
3177 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3178 if (cl1.isEmpty()) {
3179 return cl2;
3180 } else if (cl2.isEmpty()) {
3181 return cl1;
3182 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
3183 return union(cl1.tail, cl2).prepend(cl1.head);
3184 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3185 return union(cl1, cl2.tail).prepend(cl2.head);
3186 } else {
3187 return union(cl1.tail, cl2.tail).prepend(cl1.head);
3188 }
3189 }
3190
3191 /**
3192 * Intersect two closures
3193 */
3194 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3195 if (cl1 == cl2)
3196 return cl1;
3197 if (cl1.isEmpty() || cl2.isEmpty())
3198 return List.nil();
3199 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3200 return intersect(cl1.tail, cl2);
3201 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3202 return intersect(cl1, cl2.tail);
3203 if (isSameType(cl1.head, cl2.head))
3204 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3205 if (cl1.head.tsym == cl2.head.tsym &&
3206 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
3207 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3208 Type merge = merge(cl1.head,cl2.head);
3209 return intersect(cl1.tail, cl2.tail).prepend(merge);
3210 }
3211 if (cl1.head.isRaw() || cl2.head.isRaw())
3212 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3213 }
3214 return intersect(cl1.tail, cl2.tail);
3215 }
3216 // where
3217 class TypePair {
3218 final Type t1;
3219 final Type t2;
3220 TypePair(Type t1, Type t2) {
3221 this.t1 = t1;
3222 this.t2 = t2;
3223 }
3224 @Override
3225 public int hashCode() {
3226 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3227 }
3228 @Override
3229 public boolean equals(Object obj) {
3230 if (!(obj instanceof TypePair))
3231 return false;
3232 TypePair typePair = (TypePair)obj;
3233 return isSameType(t1, typePair.t1)
3234 && isSameType(t2, typePair.t2);
3235 }
3236 }
3237 Set<TypePair> mergeCache = new HashSet<TypePair>();
3238 private Type merge(Type c1, Type c2) {
3239 ClassType class1 = (ClassType) c1;
3240 List<Type> act1 = class1.getTypeArguments();
3241 ClassType class2 = (ClassType) c2;
3242 List<Type> act2 = class2.getTypeArguments();
3243 ListBuffer<Type> merged = new ListBuffer<Type>();
3244 List<Type> typarams = class1.tsym.type.getTypeArguments();
3245
3246 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3247 if (containsType(act1.head, act2.head)) {
3248 merged.append(act1.head);
3249 } else if (containsType(act2.head, act1.head)) {
3250 merged.append(act2.head);
3251 } else {
3252 TypePair pair = new TypePair(c1, c2);
3253 Type m;
3254 if (mergeCache.add(pair)) {
3255 m = new WildcardType(lub(upperBound(act1.head),
3256 upperBound(act2.head)),
3257 BoundKind.EXTENDS,
3258 syms.boundClass);
3259 mergeCache.remove(pair);
3260 } else {
3261 m = new WildcardType(syms.objectType,
3262 BoundKind.UNBOUND,
3263 syms.boundClass);
3264 }
3265 merged.append(m.withTypeVar(typarams.head));
3266 }
3267 act1 = act1.tail;
3268 act2 = act2.tail;
3269 typarams = typarams.tail;
3270 }
3271 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3272 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
3273 }
3274
3275 /**
3276 * Return the minimum type of a closure, a compound type if no
3277 * unique minimum exists.
3278 */
3279 private Type compoundMin(List<Type> cl) {
3280 if (cl.isEmpty()) return syms.objectType;
3281 List<Type> compound = closureMin(cl);
3282 if (compound.isEmpty())
3283 return null;
3284 else if (compound.tail.isEmpty())
3285 return compound.head;
3286 else
3287 return makeCompoundType(compound);
3288 }
3289
3290 /**
3291 * Return the minimum types of a closure, suitable for computing
3292 * compoundMin or glb.
3293 */
3294 private List<Type> closureMin(List<Type> cl) {
3295 ListBuffer<Type> classes = lb();
3296 ListBuffer<Type> interfaces = lb();
3297 while (!cl.isEmpty()) {
3298 Type current = cl.head;
3299 if (current.isInterface())
3300 interfaces.append(current);
3301 else
3302 classes.append(current);
3303 ListBuffer<Type> candidates = lb();
3304 for (Type t : cl.tail) {
3305 if (!isSubtypeNoCapture(current, t))
3306 candidates.append(t);
3307 }
3308 cl = candidates.toList();
3309 }
3310 return classes.appendList(interfaces).toList();
3311 }
3312
3313 /**
3314 * Return the least upper bound of pair of types. if the lub does
3315 * not exist return null.
3316 */
3317 public Type lub(Type t1, Type t2) {
3318 return lub(List.of(t1, t2));
3319 }
3320
3321 /**
3322 * Return the least upper bound (lub) of set of types. If the lub
3323 * does not exist return the type of null (bottom).
3324 */
3325 public Type lub(List<Type> ts) {
3326 final int ARRAY_BOUND = 1;
3327 final int CLASS_BOUND = 2;
3328 int boundkind = 0;
3329 for (Type t : ts) {
3330 switch (t.tag) {
3331 case CLASS:
3332 boundkind |= CLASS_BOUND;
3333 break;
3334 case ARRAY:
3335 boundkind |= ARRAY_BOUND;
3336 break;
3337 case TYPEVAR:
3338 do {
3339 t = t.getUpperBound();
3340 } while (t.tag == TYPEVAR);
3341 if (t.tag == ARRAY) {
3342 boundkind |= ARRAY_BOUND;
3343 } else {
3344 boundkind |= CLASS_BOUND;
3345 }
3346 break;
3347 default:
3348 if (t.isPrimitive())
3349 return syms.errType;
3350 }
3351 }
3352 switch (boundkind) {
3353 case 0:
3354 return syms.botType;
3355
3356 case ARRAY_BOUND:
3357 // calculate lub(A[], B[])
3358 List<Type> elements = Type.map(ts, elemTypeFun);
3359 for (Type t : elements) {
3360 if (t.isPrimitive()) {
3361 // if a primitive type is found, then return
3362 // arraySuperType unless all the types are the
3363 // same
3364 Type first = ts.head;
3365 for (Type s : ts.tail) {
3366 if (!isSameType(first, s)) {
3367 // lub(int[], B[]) is Cloneable & Serializable
3368 return arraySuperType();
3369 }
3370 }
3371 // all the array types are the same, return one
3372 // lub(int[], int[]) is int[]
3373 return first;
3374 }
3375 }
3376 // lub(A[], B[]) is lub(A, B)[]
3377 return new ArrayType(lub(elements), syms.arrayClass);
3378
3379 case CLASS_BOUND:
3380 // calculate lub(A, B)
3381 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
3382 ts = ts.tail;
3383 Assert.check(!ts.isEmpty());
3384 //step 1 - compute erased candidate set (EC)
3385 List<Type> cl = erasedSupertypes(ts.head);
3386 for (Type t : ts.tail) {
3387 if (t.tag == CLASS || t.tag == TYPEVAR)
3388 cl = intersect(cl, erasedSupertypes(t));
3389 }
3390 //step 2 - compute minimal erased candidate set (MEC)
3391 List<Type> mec = closureMin(cl);
3392 //step 3 - for each element G in MEC, compute lci(Inv(G))
3393 List<Type> candidates = List.nil();
3394 for (Type erasedSupertype : mec) {
3395 List<Type> lci = List.of(asSuper(ts.head, erasedSupertype.tsym));
3396 for (Type t : ts) {
3397 lci = intersect(lci, List.of(asSuper(t, erasedSupertype.tsym)));
3398 }
3399 candidates = candidates.appendList(lci);
3400 }
3401 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
3402 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
3403 return compoundMin(candidates);
3404
3405 default:
3406 // calculate lub(A, B[])
3407 List<Type> classes = List.of(arraySuperType());
3408 for (Type t : ts) {
3409 if (t.tag != ARRAY) // Filter out any arrays
3410 classes = classes.prepend(t);
3411 }
3412 // lub(A, B[]) is lub(A, arraySuperType)
3413 return lub(classes);
3414 }
3415 }
3416 // where
3417 List<Type> erasedSupertypes(Type t) {
3418 ListBuffer<Type> buf = lb();
3419 for (Type sup : closure(t)) {
3420 if (sup.tag == TYPEVAR) {
3421 buf.append(sup);
3422 } else {
3423 buf.append(erasure(sup));
3424 }
3425 }
3426 return buf.toList();
3427 }
3428
3429 private Type arraySuperType = null;
3430 private Type arraySuperType() {
3431 // initialized lazily to avoid problems during compiler startup
3432 if (arraySuperType == null) {
3433 synchronized (this) {
3434 if (arraySuperType == null) {
3435 // JLS 10.8: all arrays implement Cloneable and Serializable.
3436 arraySuperType = makeCompoundType(List.of(syms.serializableType,
3437 syms.cloneableType), true);
3438 }
3439 }
3440 }
3441 return arraySuperType;
3442 }
3443 // </editor-fold>
3444
3445 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
3446 public Type glb(List<Type> ts) {
3447 Type t1 = ts.head;
3448 for (Type t2 : ts.tail) {
3449 if (t1.isErroneous())
3450 return t1;
3451 t1 = glb(t1, t2);
3452 }
3453 return t1;
3454 }
3455 //where
3456 public Type glb(Type t, Type s) {
3457 if (s == null)
3458 return t;
3459 else if (t.isPrimitive() || s.isPrimitive())
3460 return syms.errType;
3461 else if (isSubtypeNoCapture(t, s))
3462 return t;
3463 else if (isSubtypeNoCapture(s, t))
3464 return s;
3465
3466 List<Type> closure = union(closure(t), closure(s));
3467 List<Type> bounds = closureMin(closure);
3468
3469 if (bounds.isEmpty()) { // length == 0
3470 return syms.objectType;
3471 } else if (bounds.tail.isEmpty()) { // length == 1
3472 return bounds.head;
3473 } else { // length > 1
3474 int classCount = 0;
3475 for (Type bound : bounds)
3476 if (!bound.isInterface())
3477 classCount++;
3478 if (classCount > 1)
3479 return createErrorType(t);
3480 }
3481 return makeCompoundType(bounds);
3482 }
3483 // </editor-fold>
3484
3485 // <editor-fold defaultstate="collapsed" desc="hashCode">
3486 /**
3487 * Compute a hash code on a type.
3488 */
3489 public int hashCode(Type t) {
3490 return hashCode.visit(t);
3491 }
3492 // where
3493 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
3494
3495 public Integer visitType(Type t, Void ignored) {
3496 return t.tag.ordinal();
3497 }
3498
3499 @Override
3500 public Integer visitClassType(ClassType t, Void ignored) {
3501 int result = visit(t.getEnclosingType());
3502 result *= 127;
3503 result += t.tsym.flatName().hashCode();
3504 for (Type s : t.getTypeArguments()) {
3505 result *= 127;
3506 result += visit(s);
3507 }
3508 return result;
3509 }
3510
3511 @Override
3512 public Integer visitMethodType(MethodType t, Void ignored) {
3513 int h = METHOD.ordinal();
3514 for (List<Type> thisargs = t.argtypes;
3515 thisargs.tail != null;
3516 thisargs = thisargs.tail)
3517 h = (h << 5) + visit(thisargs.head);
3518 return (h << 5) + visit(t.restype);
3519 }
3520
3521 @Override
3522 public Integer visitWildcardType(WildcardType t, Void ignored) {
3523 int result = t.kind.hashCode();
3524 if (t.type != null) {
3525 result *= 127;
3526 result += visit(t.type);
3527 }
3528 return result;
3529 }
3530
3531 @Override
3532 public Integer visitArrayType(ArrayType t, Void ignored) {
3533 return visit(t.elemtype) + 12;
3534 }
3535
3536 @Override
3537 public Integer visitTypeVar(TypeVar t, Void ignored) {
3538 return System.identityHashCode(t.tsym);
3539 }
3540
3541 @Override
3542 public Integer visitUndetVar(UndetVar t, Void ignored) {
3543 return System.identityHashCode(t);
3544 }
3545
3546 @Override
3547 public Integer visitErrorType(ErrorType t, Void ignored) {
3548 return 0;
3549 }
3550 };
3551 // </editor-fold>
3552
3553 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
3554 /**
3555 * Does t have a result that is a subtype of the result type of s,
3556 * suitable for covariant returns? It is assumed that both types
3557 * are (possibly polymorphic) method types. Monomorphic method
3558 * types are handled in the obvious way. Polymorphic method types
3559 * require renaming all type variables of one to corresponding
3560 * type variables in the other, where correspondence is by
3561 * position in the type parameter list. */
3562 public boolean resultSubtype(Type t, Type s, Warner warner) {
3563 List<Type> tvars = t.getTypeArguments();
3564 List<Type> svars = s.getTypeArguments();
3565 Type tres = t.getReturnType();
3566 Type sres = subst(s.getReturnType(), svars, tvars);
3567 return covariantReturnType(tres, sres, warner);
3568 }
3569
3570 /**
3571 * Return-Type-Substitutable.
3572 * @jls section 8.4.5
3573 */
3574 public boolean returnTypeSubstitutable(Type r1, Type r2) {
3575 if (hasSameArgs(r1, r2))
3576 return resultSubtype(r1, r2, noWarnings);
3577 else
3578 return covariantReturnType(r1.getReturnType(),
3579 erasure(r2.getReturnType()),
3580 noWarnings);
3581 }
3582
3583 public boolean returnTypeSubstitutable(Type r1,
3584 Type r2, Type r2res,
3585 Warner warner) {
3586 if (isSameType(r1.getReturnType(), r2res))
3587 return true;
3588 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
3589 return false;
3590
3591 if (hasSameArgs(r1, r2))
3592 return covariantReturnType(r1.getReturnType(), r2res, warner);
3593 if (!allowCovariantReturns)
3594 return false;
3595 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
3596 return true;
3597 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
3598 return false;
3599 warner.warn(LintCategory.UNCHECKED);
3600 return true;
3601 }
3602
3603 /**
3604 * Is t an appropriate return type in an overrider for a
3605 * method that returns s?
3606 */
3607 public boolean covariantReturnType(Type t, Type s, Warner warner) {
3608 return
3609 isSameType(t, s) ||
3610 allowCovariantReturns &&
3611 !t.isPrimitive() &&
3612 !s.isPrimitive() &&
3613 isAssignable(t, s, warner);
3614 }
3615 // </editor-fold>
3616
3617 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
3618 /**
3619 * Return the class that boxes the given primitive.
3620 */
3621 public ClassSymbol boxedClass(Type t) {
3622 return reader.enterClass(syms.boxedName[t.tag.ordinal()]);
3623 }
3624
3625 /**
3626 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
3627 */
3628 public Type boxedTypeOrType(Type t) {
3629 return t.isPrimitive() ?
3630 boxedClass(t).type :
3631 t;
3632 }
3633
3634 /**
3635 * Return the primitive type corresponding to a boxed type.
3636 */
3637 public Type unboxedType(Type t) {
3638 if (allowBoxing) {
3639 for (int i=0; i<syms.boxedName.length; i++) {
3640 Name box = syms.boxedName[i];
3641 if (box != null &&
3642 asSuper(t, reader.enterClass(box)) != null)
3643 return syms.typeOfTag[i];
3644 }
3645 }
3646 return Type.noType;
3647 }
3648
3649 /**
3650 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
3651 */
3652 public Type unboxedTypeOrType(Type t) {
3653 Type unboxedType = unboxedType(t);
3654 return unboxedType.tag == NONE ? t : unboxedType;
3655 }
3656 // </editor-fold>
3657
3658 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3659 /*
3660 * JLS 5.1.10 Capture Conversion:
3661 *
3662 * Let G name a generic type declaration with n formal type
3663 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3664 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3665 * where, for 1 <= i <= n:
3666 *
3667 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3668 * Si is a fresh type variable whose upper bound is
3669 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3670 * type.
3671 *
3672 * + If Ti is a wildcard type argument of the form ? extends Bi,
3673 * then Si is a fresh type variable whose upper bound is
3674 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3675 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3676 * a compile-time error if for any two classes (not interfaces)
3677 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3678 *
3679 * + If Ti is a wildcard type argument of the form ? super Bi,
3680 * then Si is a fresh type variable whose upper bound is
3681 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3682 *
3683 * + Otherwise, Si = Ti.
3684 *
3685 * Capture conversion on any type other than a parameterized type
3686 * (4.5) acts as an identity conversion (5.1.1). Capture
3687 * conversions never require a special action at run time and
3688 * therefore never throw an exception at run time.
3689 *
3690 * Capture conversion is not applied recursively.
3691 */
3692 /**
3693 * Capture conversion as specified by the JLS.
3694 */
3695
3696 public List<Type> capture(List<Type> ts) {
3697 List<Type> buf = List.nil();
3698 for (Type t : ts) {
3699 buf = buf.prepend(capture(t));
3700 }
3701 return buf.reverse();
3702 }
3703 public Type capture(Type t) {
3704 if (t.tag != CLASS)
3705 return t;
3706 if (t.getEnclosingType() != Type.noType) {
3707 Type capturedEncl = capture(t.getEnclosingType());
3708 if (capturedEncl != t.getEnclosingType()) {
3709 Type type1 = memberType(capturedEncl, t.tsym);
3710 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3711 }
3712 }
3713 t = t.unannotatedType();
3714 ClassType cls = (ClassType)t;
3715 if (cls.isRaw() || !cls.isParameterized())
3716 return cls;
3717
3718 ClassType G = (ClassType)cls.asElement().asType();
3719 List<Type> A = G.getTypeArguments();
3720 List<Type> T = cls.getTypeArguments();
3721 List<Type> S = freshTypeVariables(T);
3722
3723 List<Type> currentA = A;
3724 List<Type> currentT = T;
3725 List<Type> currentS = S;
3726 boolean captured = false;
3727 while (!currentA.isEmpty() &&
3728 !currentT.isEmpty() &&
3729 !currentS.isEmpty()) {
3730 if (currentS.head != currentT.head) {
3731 captured = true;
3732 WildcardType Ti = (WildcardType)currentT.head.unannotatedType();
3733 Type Ui = currentA.head.getUpperBound();
3734 CapturedType Si = (CapturedType)currentS.head.unannotatedType();
3735 if (Ui == null)
3736 Ui = syms.objectType;
3737 switch (Ti.kind) {
3738 case UNBOUND:
3739 Si.bound = subst(Ui, A, S);
3740 Si.lower = syms.botType;
3741 break;
3742 case EXTENDS:
3743 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3744 Si.lower = syms.botType;
3745 break;
3746 case SUPER:
3747 Si.bound = subst(Ui, A, S);
3748 Si.lower = Ti.getSuperBound();
3749 break;
3750 }
3751 if (Si.bound == Si.lower)
3752 currentS.head = Si.bound;
3753 }
3754 currentA = currentA.tail;
3755 currentT = currentT.tail;
3756 currentS = currentS.tail;
3757 }
3758 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3759 return erasure(t); // some "rare" type involved
3760
3761 if (captured)
3762 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3763 else
3764 return t;
3765 }
3766 // where
3767 public List<Type> freshTypeVariables(List<Type> types) {
3768 ListBuffer<Type> result = lb();
3769 for (Type t : types) {
3770 if (t.tag == WILDCARD) {
3771 t = t.unannotatedType();
3772 Type bound = ((WildcardType)t).getExtendsBound();
3773 if (bound == null)
3774 bound = syms.objectType;
3775 result.append(new CapturedType(capturedName,
3776 syms.noSymbol,
3777 bound,
3778 syms.botType,
3779 (WildcardType)t));
3780 } else {
3781 result.append(t);
3782 }
3783 }
3784 return result.toList();
3785 }
3786 // </editor-fold>
3787
3788 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3789 private List<Type> upperBounds(List<Type> ss) {
3790 if (ss.isEmpty()) return ss;
3791 Type head = upperBound(ss.head);
3792 List<Type> tail = upperBounds(ss.tail);
3793 if (head != ss.head || tail != ss.tail)
3794 return tail.prepend(head);
3795 else
3796 return ss;
3797 }
3798
3799 private boolean sideCast(Type from, Type to, Warner warn) {
3800 // We are casting from type $from$ to type $to$, which are
3801 // non-final unrelated types. This method
3802 // tries to reject a cast by transferring type parameters
3803 // from $to$ to $from$ by common superinterfaces.
3804 boolean reverse = false;
3805 Type target = to;
3806 if ((to.tsym.flags() & INTERFACE) == 0) {
3807 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3808 reverse = true;
3809 to = from;
3810 from = target;
3811 }
3812 List<Type> commonSupers = superClosure(to, erasure(from));
3813 boolean giveWarning = commonSupers.isEmpty();
3814 // The arguments to the supers could be unified here to
3815 // get a more accurate analysis
3816 while (commonSupers.nonEmpty()) {
3817 Type t1 = asSuper(from, commonSupers.head.tsym);
3818 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3819 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3820 return false;
3821 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3822 commonSupers = commonSupers.tail;
3823 }
3824 if (giveWarning && !isReifiable(reverse ? from : to))
3825 warn.warn(LintCategory.UNCHECKED);
3826 if (!allowCovariantReturns)
3827 // reject if there is a common method signature with
3828 // incompatible return types.
3829 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3830 return true;
3831 }
3832
3833 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3834 // We are casting from type $from$ to type $to$, which are
3835 // unrelated types one of which is final and the other of
3836 // which is an interface. This method
3837 // tries to reject a cast by transferring type parameters
3838 // from the final class to the interface.
3839 boolean reverse = false;
3840 Type target = to;
3841 if ((to.tsym.flags() & INTERFACE) == 0) {
3842 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3843 reverse = true;
3844 to = from;
3845 from = target;
3846 }
3847 Assert.check((from.tsym.flags() & FINAL) != 0);
3848 Type t1 = asSuper(from, to.tsym);
3849 if (t1 == null) return false;
3850 Type t2 = to;
3851 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3852 return false;
3853 if (!allowCovariantReturns)
3854 // reject if there is a common method signature with
3855 // incompatible return types.
3856 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3857 if (!isReifiable(target) &&
3858 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3859 warn.warn(LintCategory.UNCHECKED);
3860 return true;
3861 }
3862
3863 private boolean giveWarning(Type from, Type to) {
3864 List<Type> bounds = to.isCompound() ?
3865 ((IntersectionClassType)to.unannotatedType()).getComponents() : List.of(to);
3866 for (Type b : bounds) {
3867 Type subFrom = asSub(from, b.tsym);
3868 if (b.isParameterized() &&
3869 (!(isUnbounded(b) ||
3870 isSubtype(from, b) ||
3871 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
3872 return true;
3873 }
3874 }
3875 return false;
3876 }
3877
3878 private List<Type> superClosure(Type t, Type s) {
3879 List<Type> cl = List.nil();
3880 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3881 if (isSubtype(s, erasure(l.head))) {
3882 cl = insert(cl, l.head);
3883 } else {
3884 cl = union(cl, superClosure(l.head, s));
3885 }
3886 }
3887 return cl;
3888 }
3889
3890 private boolean containsTypeEquivalent(Type t, Type s) {
3891 return
3892 isSameType(t, s) || // shortcut
3893 containsType(t, s) && containsType(s, t);
3894 }
3895
3896 // <editor-fold defaultstate="collapsed" desc="adapt">
3897 /**
3898 * Adapt a type by computing a substitution which maps a source
3899 * type to a target type.
3900 *
3901 * @param source the source type
3902 * @param target the target type
3903 * @param from the type variables of the computed substitution
3904 * @param to the types of the computed substitution.
3905 */
3906 public void adapt(Type source,
3907 Type target,
3908 ListBuffer<Type> from,
3909 ListBuffer<Type> to) throws AdaptFailure {
3910 new Adapter(from, to).adapt(source, target);
3911 }
3912
3913 class Adapter extends SimpleVisitor<Void, Type> {
3914
3915 ListBuffer<Type> from;
3916 ListBuffer<Type> to;
3917 Map<Symbol,Type> mapping;
3918
3919 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3920 this.from = from;
3921 this.to = to;
3922 mapping = new HashMap<Symbol,Type>();
3923 }
3924
3925 public void adapt(Type source, Type target) throws AdaptFailure {
3926 visit(source, target);
3927 List<Type> fromList = from.toList();
3928 List<Type> toList = to.toList();
3929 while (!fromList.isEmpty()) {
3930 Type val = mapping.get(fromList.head.tsym);
3931 if (toList.head != val)
3932 toList.head = val;
3933 fromList = fromList.tail;
3934 toList = toList.tail;
3935 }
3936 }
3937
3938 @Override
3939 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3940 if (target.tag == CLASS)
3941 adaptRecursive(source.allparams(), target.allparams());
3942 return null;
3943 }
3944
3945 @Override
3946 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3947 if (target.tag == ARRAY)
3948 adaptRecursive(elemtype(source), elemtype(target));
3949 return null;
3950 }
3951
3952 @Override
3953 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3954 if (source.isExtendsBound())
3955 adaptRecursive(upperBound(source), upperBound(target));
3956 else if (source.isSuperBound())
3957 adaptRecursive(lowerBound(source), lowerBound(target));
3958 return null;
3959 }
3960
3961 @Override
3962 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3963 // Check to see if there is
3964 // already a mapping for $source$, in which case
3965 // the old mapping will be merged with the new
3966 Type val = mapping.get(source.tsym);
3967 if (val != null) {
3968 if (val.isSuperBound() && target.isSuperBound()) {
3969 val = isSubtype(lowerBound(val), lowerBound(target))
3970 ? target : val;
3971 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3972 val = isSubtype(upperBound(val), upperBound(target))
3973 ? val : target;
3974 } else if (!isSameType(val, target)) {
3975 throw new AdaptFailure();
3976 }
3977 } else {
3978 val = target;
3979 from.append(source);
3980 to.append(target);
3981 }
3982 mapping.put(source.tsym, val);
3983 return null;
3984 }
3985
3986 @Override
3987 public Void visitType(Type source, Type target) {
3988 return null;
3989 }
3990
3991 private Set<TypePair> cache = new HashSet<TypePair>();
3992
3993 private void adaptRecursive(Type source, Type target) {
3994 TypePair pair = new TypePair(source, target);
3995 if (cache.add(pair)) {
3996 try {
3997 visit(source, target);
3998 } finally {
3999 cache.remove(pair);
4000 }
4001 }
4002 }
4003
4004 private void adaptRecursive(List<Type> source, List<Type> target) {
4005 if (source.length() == target.length()) {
4006 while (source.nonEmpty()) {
4007 adaptRecursive(source.head, target.head);
4008 source = source.tail;
4009 target = target.tail;
4010 }
4011 }
4012 }
4013 }
4014
4015 public static class AdaptFailure extends RuntimeException {
4016 static final long serialVersionUID = -7490231548272701566L;
4017 }
4018
4019 private void adaptSelf(Type t,
4020 ListBuffer<Type> from,
4021 ListBuffer<Type> to) {
4022 try {
4023 //if (t.tsym.type != t)
4024 adapt(t.tsym.type, t, from, to);
4025 } catch (AdaptFailure ex) {
4026 // Adapt should never fail calculating a mapping from
4027 // t.tsym.type to t as there can be no merge problem.
4028 throw new AssertionError(ex);
4029 }
4030 }
4031 // </editor-fold>
4032
4033 /**
4034 * Rewrite all type variables (universal quantifiers) in the given
4035 * type to wildcards (existential quantifiers). This is used to
4036 * determine if a cast is allowed. For example, if high is true
4037 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4038 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4039 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4040 * List<Integer>} with a warning.
4041 * @param t a type
4042 * @param high if true return an upper bound; otherwise a lower
4043 * bound
4044 * @param rewriteTypeVars only rewrite captured wildcards if false;
4045 * otherwise rewrite all type variables
4046 * @return the type rewritten with wildcards (existential
4047 * quantifiers) only
4048 */
4049 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4050 return new Rewriter(high, rewriteTypeVars).visit(t);
4051 }
4052
4053 class Rewriter extends UnaryVisitor<Type> {
4054
4055 boolean high;
4056 boolean rewriteTypeVars;
4057
4058 Rewriter(boolean high, boolean rewriteTypeVars) {
4059 this.high = high;
4060 this.rewriteTypeVars = rewriteTypeVars;
4061 }
4062
4063 @Override
4064 public Type visitClassType(ClassType t, Void s) {
4065 ListBuffer<Type> rewritten = new ListBuffer<Type>();
4066 boolean changed = false;
4067 for (Type arg : t.allparams()) {
4068 Type bound = visit(arg);
4069 if (arg != bound) {
4070 changed = true;
4071 }
4072 rewritten.append(bound);
4073 }
4074 if (changed)
4075 return subst(t.tsym.type,
4076 t.tsym.type.allparams(),
4077 rewritten.toList());
4078 else
4079 return t;
4080 }
4081
4082 public Type visitType(Type t, Void s) {
4083 return high ? upperBound(t) : lowerBound(t);
4084 }
4085
4086 @Override
4087 public Type visitCapturedType(CapturedType t, Void s) {
4088 Type w_bound = t.wildcard.type;
4089 Type bound = w_bound.contains(t) ?
4090 erasure(w_bound) :
4091 visit(w_bound);
4092 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4093 }
4094
4095 @Override
4096 public Type visitTypeVar(TypeVar t, Void s) {
4097 if (rewriteTypeVars) {
4098 Type bound = t.bound.contains(t) ?
4099 erasure(t.bound) :
4100 visit(t.bound);
4101 return rewriteAsWildcardType(bound, t, EXTENDS);
4102 } else {
4103 return t;
4104 }
4105 }
4106
4107 @Override
4108 public Type visitWildcardType(WildcardType t, Void s) {
4109 Type bound2 = visit(t.type);
4110 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4111 }
4112
4113 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4114 switch (bk) {
4115 case EXTENDS: return high ?
4116 makeExtendsWildcard(B(bound), formal) :
4117 makeExtendsWildcard(syms.objectType, formal);
4118 case SUPER: return high ?
4119 makeSuperWildcard(syms.botType, formal) :
4120 makeSuperWildcard(B(bound), formal);
4121 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4122 default:
4123 Assert.error("Invalid bound kind " + bk);
4124 return null;
4125 }
4126 }
4127
4128 Type B(Type t) {
4129 while (t.tag == WILDCARD) {
4130 WildcardType w = (WildcardType)t.unannotatedType();
4131 t = high ?
4132 w.getExtendsBound() :
4133 w.getSuperBound();
4134 if (t == null) {
4135 t = high ? syms.objectType : syms.botType;
4136 }
4137 }
4138 return t;
4139 }
4140 }
4141
4142
4143 /**
4144 * Create a wildcard with the given upper (extends) bound; create
4145 * an unbounded wildcard if bound is Object.
4146 *
4147 * @param bound the upper bound
4148 * @param formal the formal type parameter that will be
4149 * substituted by the wildcard
4150 */
4151 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4152 if (bound == syms.objectType) {
4153 return new WildcardType(syms.objectType,
4154 BoundKind.UNBOUND,
4155 syms.boundClass,
4156 formal);
4157 } else {
4158 return new WildcardType(bound,
4159 BoundKind.EXTENDS,
4160 syms.boundClass,
4161 formal);
4162 }
4163 }
4164
4165 /**
4166 * Create a wildcard with the given lower (super) bound; create an
4167 * unbounded wildcard if bound is bottom (type of {@code null}).
4168 *
4169 * @param bound the lower bound
4170 * @param formal the formal type parameter that will be
4171 * substituted by the wildcard
4172 */
4173 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4174 if (bound.tag == BOT) {
4175 return new WildcardType(syms.objectType,
4176 BoundKind.UNBOUND,
4177 syms.boundClass,
4178 formal);
4179 } else {
4180 return new WildcardType(bound,
4181 BoundKind.SUPER,
4182 syms.boundClass,
4183 formal);
4184 }
4185 }
4186
4187 /**
4188 * A wrapper for a type that allows use in sets.
4189 */
4190 public static class UniqueType {
4191 public final Type type;
4192 final Types types;
4193
4194 public UniqueType(Type type, Types types) {
4195 this.type = type;
4196 this.types = types;
4197 }
4198
4199 public int hashCode() {
4200 return types.hashCode(type);
4201 }
4202
4203 public boolean equals(Object obj) {
4204 return (obj instanceof UniqueType) &&
4205 types.isSameAnnotatedType(type, ((UniqueType)obj).type);
4206 }
4207
4208 public String toString() {
4209 return type.toString();
4210 }
4211
4212 }
4213 // </editor-fold>
4214
4215 // <editor-fold defaultstate="collapsed" desc="Visitors">
4216 /**
4217 * A default visitor for types. All visitor methods except
4218 * visitType are implemented by delegating to visitType. Concrete
4219 * subclasses must provide an implementation of visitType and can
4220 * override other methods as needed.
4221 *
4222 * @param <R> the return type of the operation implemented by this
4223 * visitor; use Void if no return type is needed.
4224 * @param <S> the type of the second argument (the first being the
4225 * type itself) of the operation implemented by this visitor; use
4226 * Void if a second argument is not needed.
4227 */
4228 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4229 final public R visit(Type t, S s) { return t.accept(this, s); }
4230 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4231 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4232 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4233 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4234 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4235 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4236 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4237 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4238 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4239 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4240 // Pretend annotations don't exist
4241 public R visitAnnotatedType(AnnotatedType t, S s) { return visit(t.underlyingType, s); }
4242 }
4243
4244 /**
4245 * A default visitor for symbols. All visitor methods except
4246 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4247 * subclasses must provide an implementation of visitSymbol and can
4248 * override other methods as needed.
4249 *
4250 * @param <R> the return type of the operation implemented by this
4251 * visitor; use Void if no return type is needed.
4252 * @param <S> the type of the second argument (the first being the
4253 * symbol itself) of the operation implemented by this visitor; use
4254 * Void if a second argument is not needed.
4255 */
4256 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4257 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
4258 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4259 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4260 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4261 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4262 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4263 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4264 }
4265
4266 /**
4267 * A <em>simple</em> visitor for types. This visitor is simple as
4268 * captured wildcards, for-all types (generic methods), and
4269 * undetermined type variables (part of inference) are hidden.
4270 * Captured wildcards are hidden by treating them as type
4271 * variables and the rest are hidden by visiting their qtypes.
4272 *
4273 * @param <R> the return type of the operation implemented by this
4274 * visitor; use Void if no return type is needed.
4275 * @param <S> the type of the second argument (the first being the
4276 * type itself) of the operation implemented by this visitor; use
4277 * Void if a second argument is not needed.
4278 */
4279 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4280 @Override
4281 public R visitCapturedType(CapturedType t, S s) {
4282 return visitTypeVar(t, s);
4283 }
4284 @Override
4285 public R visitForAll(ForAll t, S s) {
4286 return visit(t.qtype, s);
4287 }
4288 @Override
4289 public R visitUndetVar(UndetVar t, S s) {
4290 return visit(t.qtype, s);
4291 }
4292 }
4293
4294 /**
4295 * A plain relation on types. That is a 2-ary function on the
4296 * form Type × Type → Boolean.
4297 * <!-- In plain text: Type x Type -> Boolean -->
4298 */
4299 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4300
4301 /**
4302 * A convenience visitor for implementing operations that only
4303 * require one argument (the type itself), that is, unary
4304 * operations.
4305 *
4306 * @param <R> the return type of the operation implemented by this
4307 * visitor; use Void if no return type is needed.
4308 */
4309 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4310 final public R visit(Type t) { return t.accept(this, null); }
4311 }
4312
4313 /**
4314 * A visitor for implementing a mapping from types to types. The
4315 * default behavior of this class is to implement the identity
4316 * mapping (mapping a type to itself). This can be overridden in
4317 * subclasses.
4318 *
4319 * @param <S> the type of the second argument (the first being the
4320 * type itself) of this mapping; use Void if a second argument is
4321 * not needed.
4322 */
4323 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4324 final public Type visit(Type t) { return t.accept(this, null); }
4325 public Type visitType(Type t, S s) { return t; }
4326 }
4327 // </editor-fold>
4328
4329
4330 // <editor-fold defaultstate="collapsed" desc="Annotation support">
4331
4332 public RetentionPolicy getRetention(Attribute.Compound a) {
4333 return getRetention(a.type.tsym);
4334 }
4335
4336 public RetentionPolicy getRetention(Symbol sym) {
4337 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
4338 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
4339 if (c != null) {
4340 Attribute value = c.member(names.value);
4341 if (value != null && value instanceof Attribute.Enum) {
4342 Name levelName = ((Attribute.Enum)value).value.name;
4343 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
4344 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
4345 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
4346 else ;// /* fail soft */ throw new AssertionError(levelName);
4347 }
4348 }
4349 return vis;
4350 }
4351 // </editor-fold>
4352
4353 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
4354
4355 public static abstract class SignatureGenerator {
4356
4357 private final Types types;
4358
4359 protected abstract void append(char ch);
4360 protected abstract void append(byte[] ba);
4361 protected abstract void append(Name name);
4362 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
4363
4364 protected SignatureGenerator(Types types) {
4365 this.types = types;
4366 }
4367
4368 /**
4369 * Assemble signature of given type in string buffer.
4370 */
4371 public void assembleSig(Type type) {
4372 type = type.unannotatedType();
4373 switch (type.getTag()) {
4374 case BYTE:
4375 append('B');
4376 break;
4377 case SHORT:
4378 append('S');
4379 break;
4380 case CHAR:
4381 append('C');
4382 break;
4383 case INT:
4384 append('I');
4385 break;
4386 case LONG:
4387 append('J');
4388 break;
4389 case FLOAT:
4390 append('F');
4391 break;
4392 case DOUBLE:
4393 append('D');
4394 break;
4395 case BOOLEAN:
4396 append('Z');
4397 break;
4398 case VOID:
4399 append('V');
4400 break;
4401 case CLASS:
4402 append('L');
4403 assembleClassSig(type);
4404 append(';');
4405 break;
4406 case ARRAY:
4407 ArrayType at = (ArrayType) type;
4408 append('[');
4409 assembleSig(at.elemtype);
4410 break;
4411 case METHOD:
4412 MethodType mt = (MethodType) type;
4413 append('(');
4414 assembleSig(mt.argtypes);
4415 append(')');
4416 assembleSig(mt.restype);
4417 if (hasTypeVar(mt.thrown)) {
4418 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
4419 append('^');
4420 assembleSig(l.head);
4421 }
4422 }
4423 break;
4424 case WILDCARD: {
4425 Type.WildcardType ta = (Type.WildcardType) type;
4426 switch (ta.kind) {
4427 case SUPER:
4428 append('-');
4429 assembleSig(ta.type);
4430 break;
4431 case EXTENDS:
4432 append('+');
4433 assembleSig(ta.type);
4434 break;
4435 case UNBOUND:
4436 append('*');
4437 break;
4438 default:
4439 throw new AssertionError(ta.kind);
4440 }
4441 break;
4442 }
4443 case TYPEVAR:
4444 append('T');
4445 append(type.tsym.name);
4446 append(';');
4447 break;
4448 case FORALL:
4449 Type.ForAll ft = (Type.ForAll) type;
4450 assembleParamsSig(ft.tvars);
4451 assembleSig(ft.qtype);
4452 break;
4453 default:
4454 throw new AssertionError("typeSig " + type.getTag());
4455 }
4456 }
4457
4458 public boolean hasTypeVar(List<Type> l) {
4459 while (l.nonEmpty()) {
4460 if (l.head.hasTag(TypeTag.TYPEVAR)) {
4461 return true;
4462 }
4463 l = l.tail;
4464 }
4465 return false;
4466 }
4467
4468 public void assembleClassSig(Type type) {
4469 type = type.unannotatedType();
4470 ClassType ct = (ClassType) type;
4471 ClassSymbol c = (ClassSymbol) ct.tsym;
4472 classReference(c);
4473 Type outer = ct.getEnclosingType();
4474 if (outer.allparams().nonEmpty()) {
4475 boolean rawOuter =
4476 c.owner.kind == Kinds.MTH || // either a local class
4477 c.name == types.names.empty; // or anonymous
4478 assembleClassSig(rawOuter
4479 ? types.erasure(outer)
4480 : outer);
4481 append('.');
4482 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
4483 append(rawOuter
4484 ? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength())
4485 : c.name);
4486 } else {
4487 append(externalize(c.flatname));
4488 }
4489 if (ct.getTypeArguments().nonEmpty()) {
4490 append('<');
4491 assembleSig(ct.getTypeArguments());
4492 append('>');
4493 }
4494 }
4495
4496 public void assembleParamsSig(List<Type> typarams) {
4497 append('<');
4498 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
4499 Type.TypeVar tvar = (Type.TypeVar) ts.head;
4500 append(tvar.tsym.name);
4501 List<Type> bounds = types.getBounds(tvar);
4502 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
4503 append(':');
4504 }
4505 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
4506 append(':');
4507 assembleSig(l.head);
4508 }
4509 }
4510 append('>');
4511 }
4512
4513 private void assembleSig(List<Type> types) {
4514 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
4515 assembleSig(ts.head);
4516 }
4517 }
4518 }
4519 // </editor-fold>
4520 }