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src/share/classes/com/sun/tools/javac/code/Types.java@71f35e4b93a5
src/share/classes/com/sun/tools/javac/code/Types.java
Wed, 23 Jan 2013 13:27:24 -0800
- author
- jjg
- date
- Wed, 23 Jan 2013 13:27:24 -0800
- changeset 1521
- 71f35e4b93a5
- parent 1510
- 7873d37f5b37
- child 1550
- 1df20330f6bd
- permissions
- -rw-r--r--
8006775: JSR 308: Compiler changes in JDK8
Reviewed-by: jjg
Contributed-by: mernst@cs.washington.edu, wmdietl@cs.washington.edu, mpapi@csail.mit.edu, mahmood@notnoop.com
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 */
26 package com.sun.tools.javac.code;
28 import java.lang.ref.SoftReference;
29 import java.util.Comparator;
30 import java.util.HashSet;
31 import java.util.HashMap;
32 import java.util.Locale;
33 import java.util.Map;
34 import java.util.Set;
35 import java.util.WeakHashMap;
37 import javax.lang.model.type.TypeKind;
39 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
40 import com.sun.tools.javac.code.Lint.LintCategory;
41 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
42 import com.sun.tools.javac.comp.Check;
43 import com.sun.tools.javac.jvm.ClassReader;
44 import com.sun.tools.javac.util.*;
45 import static com.sun.tools.javac.code.BoundKind.*;
46 import static com.sun.tools.javac.code.Flags.*;
47 import static com.sun.tools.javac.code.Scope.*;
48 import static com.sun.tools.javac.code.Symbol.*;
49 import static com.sun.tools.javac.code.Type.*;
50 import static com.sun.tools.javac.code.TypeTag.*;
51 import static com.sun.tools.javac.util.ListBuffer.lb;
53 /**
54 * Utility class containing various operations on types.
55 *
56 * <p>Unless other names are more illustrative, the following naming
57 * conventions should be observed in this file:
58 *
59 * <dl>
60 * <dt>t</dt>
61 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
62 * <dt>s</dt>
63 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
64 * <dt>ts</dt>
65 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
66 * <dt>ss</dt>
67 * <dd>A second list of types should be named ss.</dd>
68 * </dl>
69 *
70 * <p><b>This is NOT part of any supported API.
71 * If you write code that depends on this, you do so at your own risk.
72 * This code and its internal interfaces are subject to change or
73 * deletion without notice.</b>
74 */
75 public class Types {
76 protected static final Context.Key<Types> typesKey =
77 new Context.Key<Types>();
79 final Symtab syms;
80 final JavacMessages messages;
81 final Names names;
82 final boolean allowBoxing;
83 final boolean allowCovariantReturns;
84 final boolean allowObjectToPrimitiveCast;
85 final boolean allowDefaultMethods;
86 final ClassReader reader;
87 final Check chk;
88 JCDiagnostic.Factory diags;
89 List<Warner> warnStack = List.nil();
90 final Name capturedName;
91 private final FunctionDescriptorLookupError functionDescriptorLookupError;
93 public final Warner noWarnings;
95 // <editor-fold defaultstate="collapsed" desc="Instantiating">
96 public static Types instance(Context context) {
97 Types instance = context.get(typesKey);
98 if (instance == null)
99 instance = new Types(context);
100 return instance;
101 }
103 protected Types(Context context) {
104 context.put(typesKey, this);
105 syms = Symtab.instance(context);
106 names = Names.instance(context);
107 Source source = Source.instance(context);
108 allowBoxing = source.allowBoxing();
109 allowCovariantReturns = source.allowCovariantReturns();
110 allowObjectToPrimitiveCast = source.allowObjectToPrimitiveCast();
111 allowDefaultMethods = source.allowDefaultMethods();
112 reader = ClassReader.instance(context);
113 chk = Check.instance(context);
114 capturedName = names.fromString("<captured wildcard>");
115 messages = JavacMessages.instance(context);
116 diags = JCDiagnostic.Factory.instance(context);
117 functionDescriptorLookupError = new FunctionDescriptorLookupError();
118 noWarnings = new Warner(null);
119 }
120 // </editor-fold>
122 // <editor-fold defaultstate="collapsed" desc="upperBound">
123 /**
124 * The "rvalue conversion".<br>
125 * The upper bound of most types is the type
126 * itself. Wildcards, on the other hand have upper
127 * and lower bounds.
128 * @param t a type
129 * @return the upper bound of the given type
130 */
131 public Type upperBound(Type t) {
132 return upperBound.visit(t);
133 }
134 // where
135 private final MapVisitor<Void> upperBound = new MapVisitor<Void>() {
137 @Override
138 public Type visitWildcardType(WildcardType t, Void ignored) {
139 if (t.isSuperBound())
140 return t.bound == null ? syms.objectType : t.bound.bound;
141 else
142 return visit(t.type);
143 }
145 @Override
146 public Type visitCapturedType(CapturedType t, Void ignored) {
147 return visit(t.bound);
148 }
149 };
150 // </editor-fold>
152 // <editor-fold defaultstate="collapsed" desc="lowerBound">
153 /**
154 * The "lvalue conversion".<br>
155 * The lower bound of most types is the type
156 * itself. Wildcards, on the other hand have upper
157 * and lower bounds.
158 * @param t a type
159 * @return the lower bound of the given type
160 */
161 public Type lowerBound(Type t) {
162 return lowerBound.visit(t);
163 }
164 // where
165 private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() {
167 @Override
168 public Type visitWildcardType(WildcardType t, Void ignored) {
169 return t.isExtendsBound() ? syms.botType : visit(t.type);
170 }
172 @Override
173 public Type visitCapturedType(CapturedType t, Void ignored) {
174 return visit(t.getLowerBound());
175 }
176 };
177 // </editor-fold>
179 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
180 /**
181 * Checks that all the arguments to a class are unbounded
182 * wildcards or something else that doesn't make any restrictions
183 * on the arguments. If a class isUnbounded, a raw super- or
184 * subclass can be cast to it without a warning.
185 * @param t a type
186 * @return true iff the given type is unbounded or raw
187 */
188 public boolean isUnbounded(Type t) {
189 return isUnbounded.visit(t);
190 }
191 // where
192 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
194 public Boolean visitType(Type t, Void ignored) {
195 return true;
196 }
198 @Override
199 public Boolean visitClassType(ClassType t, Void ignored) {
200 List<Type> parms = t.tsym.type.allparams();
201 List<Type> args = t.allparams();
202 while (parms.nonEmpty()) {
203 WildcardType unb = new WildcardType(syms.objectType,
204 BoundKind.UNBOUND,
205 syms.boundClass,
206 (TypeVar)parms.head);
207 if (!containsType(args.head, unb))
208 return false;
209 parms = parms.tail;
210 args = args.tail;
211 }
212 return true;
213 }
214 };
215 // </editor-fold>
217 // <editor-fold defaultstate="collapsed" desc="asSub">
218 /**
219 * Return the least specific subtype of t that starts with symbol
220 * sym. If none exists, return null. The least specific subtype
221 * is determined as follows:
222 *
223 * <p>If there is exactly one parameterized instance of sym that is a
224 * subtype of t, that parameterized instance is returned.<br>
225 * Otherwise, if the plain type or raw type `sym' is a subtype of
226 * type t, the type `sym' itself is returned. Otherwise, null is
227 * returned.
228 */
229 public Type asSub(Type t, Symbol sym) {
230 return asSub.visit(t, sym);
231 }
232 // where
233 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
235 public Type visitType(Type t, Symbol sym) {
236 return null;
237 }
239 @Override
240 public Type visitClassType(ClassType t, Symbol sym) {
241 if (t.tsym == sym)
242 return t;
243 Type base = asSuper(sym.type, t.tsym);
244 if (base == null)
245 return null;
246 ListBuffer<Type> from = new ListBuffer<Type>();
247 ListBuffer<Type> to = new ListBuffer<Type>();
248 try {
249 adapt(base, t, from, to);
250 } catch (AdaptFailure ex) {
251 return null;
252 }
253 Type res = subst(sym.type, from.toList(), to.toList());
254 if (!isSubtype(res, t))
255 return null;
256 ListBuffer<Type> openVars = new ListBuffer<Type>();
257 for (List<Type> l = sym.type.allparams();
258 l.nonEmpty(); l = l.tail)
259 if (res.contains(l.head) && !t.contains(l.head))
260 openVars.append(l.head);
261 if (openVars.nonEmpty()) {
262 if (t.isRaw()) {
263 // The subtype of a raw type is raw
264 res = erasure(res);
265 } else {
266 // Unbound type arguments default to ?
267 List<Type> opens = openVars.toList();
268 ListBuffer<Type> qs = new ListBuffer<Type>();
269 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
270 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head));
271 }
272 res = subst(res, opens, qs.toList());
273 }
274 }
275 return res;
276 }
278 @Override
279 public Type visitErrorType(ErrorType t, Symbol sym) {
280 return t;
281 }
282 };
283 // </editor-fold>
285 // <editor-fold defaultstate="collapsed" desc="isConvertible">
286 /**
287 * Is t a subtype of or convertible via boxing/unboxing
288 * conversion to s?
289 */
290 public boolean isConvertible(Type t, Type s, Warner warn) {
291 if (t.tag == ERROR)
292 return true;
293 boolean tPrimitive = t.isPrimitive();
294 boolean sPrimitive = s.isPrimitive();
295 if (tPrimitive == sPrimitive) {
296 return isSubtypeUnchecked(t, s, warn);
297 }
298 if (!allowBoxing) return false;
299 return tPrimitive
300 ? isSubtype(boxedClass(t).type, s)
301 : isSubtype(unboxedType(t), s);
302 }
304 /**
305 * Is t a subtype of or convertiable via boxing/unboxing
306 * convertions to s?
307 */
308 public boolean isConvertible(Type t, Type s) {
309 return isConvertible(t, s, noWarnings);
310 }
311 // </editor-fold>
313 // <editor-fold defaultstate="collapsed" desc="findSam">
315 /**
316 * Exception used to report a function descriptor lookup failure. The exception
317 * wraps a diagnostic that can be used to generate more details error
318 * messages.
319 */
320 public static class FunctionDescriptorLookupError extends RuntimeException {
321 private static final long serialVersionUID = 0;
323 JCDiagnostic diagnostic;
325 FunctionDescriptorLookupError() {
326 this.diagnostic = null;
327 }
329 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
330 this.diagnostic = diag;
331 return this;
332 }
334 public JCDiagnostic getDiagnostic() {
335 return diagnostic;
336 }
337 }
339 /**
340 * A cache that keeps track of function descriptors associated with given
341 * functional interfaces.
342 */
343 class DescriptorCache {
345 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<TypeSymbol, Entry>();
347 class FunctionDescriptor {
348 Symbol descSym;
350 FunctionDescriptor(Symbol descSym) {
351 this.descSym = descSym;
352 }
354 public Symbol getSymbol() {
355 return descSym;
356 }
358 public Type getType(Type site) {
359 if (capture(site) != site) {
360 Type formalInterface = site.tsym.type;
361 ListBuffer<Type> typeargs = ListBuffer.lb();
362 List<Type> actualTypeargs = site.getTypeArguments();
363 //simply replace the wildcards with its bound
364 for (Type t : formalInterface.getTypeArguments()) {
365 if (actualTypeargs.head.hasTag(WILDCARD)) {
366 WildcardType wt = (WildcardType)actualTypeargs.head;
367 typeargs.append(wt.type);
368 } else {
369 typeargs.append(actualTypeargs.head);
370 }
371 actualTypeargs = actualTypeargs.tail;
372 }
373 site = subst(formalInterface, formalInterface.getTypeArguments(), typeargs.toList());
374 if (!chk.checkValidGenericType(site)) {
375 //if the inferred functional interface type is not well-formed,
376 //or if it's not a subtype of the original target, issue an error
377 throw failure(diags.fragment("no.suitable.functional.intf.inst", site));
378 }
379 }
380 return memberType(site, descSym);
381 }
382 }
384 class Entry {
385 final FunctionDescriptor cachedDescRes;
386 final int prevMark;
388 public Entry(FunctionDescriptor cachedDescRes,
389 int prevMark) {
390 this.cachedDescRes = cachedDescRes;
391 this.prevMark = prevMark;
392 }
394 boolean matches(int mark) {
395 return this.prevMark == mark;
396 }
397 }
399 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
400 Entry e = _map.get(origin);
401 CompoundScope members = membersClosure(origin.type, false);
402 if (e == null ||
403 !e.matches(members.getMark())) {
404 FunctionDescriptor descRes = findDescriptorInternal(origin, members);
405 _map.put(origin, new Entry(descRes, members.getMark()));
406 return descRes;
407 }
408 else {
409 return e.cachedDescRes;
410 }
411 }
413 /**
414 * Compute the function descriptor associated with a given functional interface
415 */
416 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin, CompoundScope membersCache) throws FunctionDescriptorLookupError {
417 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0) {
418 //t must be an interface
419 throw failure("not.a.functional.intf", origin);
420 }
422 final ListBuffer<Symbol> abstracts = ListBuffer.lb();
423 for (Symbol sym : membersCache.getElements(new DescriptorFilter(origin))) {
424 Type mtype = memberType(origin.type, sym);
425 if (abstracts.isEmpty() ||
426 (sym.name == abstracts.first().name &&
427 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
428 abstracts.append(sym);
429 } else {
430 //the target method(s) should be the only abstract members of t
431 throw failure("not.a.functional.intf.1", origin,
432 diags.fragment("incompatible.abstracts", Kinds.kindName(origin), origin));
433 }
434 }
435 if (abstracts.isEmpty()) {
436 //t must define a suitable non-generic method
437 throw failure("not.a.functional.intf.1", origin,
438 diags.fragment("no.abstracts", Kinds.kindName(origin), origin));
439 } else if (abstracts.size() == 1) {
440 return new FunctionDescriptor(abstracts.first());
441 } else { // size > 1
442 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
443 if (descRes == null) {
444 //we can get here if the functional interface is ill-formed
445 ListBuffer<JCDiagnostic> descriptors = ListBuffer.lb();
446 for (Symbol desc : abstracts) {
447 String key = desc.type.getThrownTypes().nonEmpty() ?
448 "descriptor.throws" : "descriptor";
449 descriptors.append(diags.fragment(key, desc.name,
450 desc.type.getParameterTypes(),
451 desc.type.getReturnType(),
452 desc.type.getThrownTypes()));
453 }
454 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
455 new JCDiagnostic.MultilineDiagnostic(diags.fragment("incompatible.descs.in.functional.intf",
456 Kinds.kindName(origin), origin), descriptors.toList());
457 throw failure(incompatibleDescriptors);
458 }
459 return descRes;
460 }
461 }
463 /**
464 * Compute a synthetic type for the target descriptor given a list
465 * of override-equivalent methods in the functional interface type.
466 * The resulting method type is a method type that is override-equivalent
467 * and return-type substitutable with each method in the original list.
468 */
469 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
470 //pick argument types - simply take the signature that is a
471 //subsignature of all other signatures in the list (as per JLS 8.4.2)
472 List<Symbol> mostSpecific = List.nil();
473 outer: for (Symbol msym1 : methodSyms) {
474 Type mt1 = memberType(origin.type, msym1);
475 for (Symbol msym2 : methodSyms) {
476 Type mt2 = memberType(origin.type, msym2);
477 if (!isSubSignature(mt1, mt2)) {
478 continue outer;
479 }
480 }
481 mostSpecific = mostSpecific.prepend(msym1);
482 }
483 if (mostSpecific.isEmpty()) {
484 return null;
485 }
488 //pick return types - this is done in two phases: (i) first, the most
489 //specific return type is chosen using strict subtyping; if this fails,
490 //a second attempt is made using return type substitutability (see JLS 8.4.5)
491 boolean phase2 = false;
492 Symbol bestSoFar = null;
493 while (bestSoFar == null) {
494 outer: for (Symbol msym1 : mostSpecific) {
495 Type mt1 = memberType(origin.type, msym1);
496 for (Symbol msym2 : methodSyms) {
497 Type mt2 = memberType(origin.type, msym2);
498 if (phase2 ?
499 !returnTypeSubstitutable(mt1, mt2) :
500 !isSubtypeInternal(mt1.getReturnType(), mt2.getReturnType())) {
501 continue outer;
502 }
503 }
504 bestSoFar = msym1;
505 }
506 if (phase2) {
507 break;
508 } else {
509 phase2 = true;
510 }
511 }
512 if (bestSoFar == null) return null;
514 //merge thrown types - form the intersection of all the thrown types in
515 //all the signatures in the list
516 List<Type> thrown = null;
517 for (Symbol msym1 : methodSyms) {
518 Type mt1 = memberType(origin.type, msym1);
519 thrown = (thrown == null) ?
520 mt1.getThrownTypes() :
521 chk.intersect(mt1.getThrownTypes(), thrown);
522 }
524 final List<Type> thrown1 = thrown;
525 return new FunctionDescriptor(bestSoFar) {
526 @Override
527 public Type getType(Type origin) {
528 Type mt = memberType(origin, getSymbol());
529 return new MethodType(mt.getParameterTypes(), mt.getReturnType(), thrown1, syms.methodClass);
530 }
531 };
532 }
534 boolean isSubtypeInternal(Type s, Type t) {
535 return (s.isPrimitive() && t.isPrimitive()) ?
536 isSameType(t, s) :
537 isSubtype(s, t);
538 }
540 FunctionDescriptorLookupError failure(String msg, Object... args) {
541 return failure(diags.fragment(msg, args));
542 }
544 FunctionDescriptorLookupError failure(JCDiagnostic diag) {
545 return functionDescriptorLookupError.setMessage(diag);
546 }
547 }
549 private DescriptorCache descCache = new DescriptorCache();
551 /**
552 * Find the method descriptor associated to this class symbol - if the
553 * symbol 'origin' is not a functional interface, an exception is thrown.
554 */
555 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
556 return descCache.get(origin).getSymbol();
557 }
559 /**
560 * Find the type of the method descriptor associated to this class symbol -
561 * if the symbol 'origin' is not a functional interface, an exception is thrown.
562 */
563 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
564 return descCache.get(origin.tsym).getType(origin);
565 }
567 /**
568 * Is given type a functional interface?
569 */
570 public boolean isFunctionalInterface(TypeSymbol tsym) {
571 try {
572 findDescriptorSymbol(tsym);
573 return true;
574 } catch (FunctionDescriptorLookupError ex) {
575 return false;
576 }
577 }
579 public boolean isFunctionalInterface(Type site) {
580 try {
581 findDescriptorType(site);
582 return true;
583 } catch (FunctionDescriptorLookupError ex) {
584 return false;
585 }
586 }
587 // </editor-fold>
589 /**
590 * Scope filter used to skip methods that should be ignored (such as methods
591 * overridden by j.l.Object) during function interface conversion/marker interface checks
592 */
593 class DescriptorFilter implements Filter<Symbol> {
595 TypeSymbol origin;
597 DescriptorFilter(TypeSymbol origin) {
598 this.origin = origin;
599 }
601 @Override
602 public boolean accepts(Symbol sym) {
603 return sym.kind == Kinds.MTH &&
604 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
605 !overridesObjectMethod(origin, sym) &&
606 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
607 }
608 };
610 // <editor-fold defaultstate="collapsed" desc="isMarker">
612 /**
613 * A cache that keeps track of marker interfaces
614 */
615 class MarkerCache {
617 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<TypeSymbol, Entry>();
619 class Entry {
620 final boolean isMarkerIntf;
621 final int prevMark;
623 public Entry(boolean isMarkerIntf,
624 int prevMark) {
625 this.isMarkerIntf = isMarkerIntf;
626 this.prevMark = prevMark;
627 }
629 boolean matches(int mark) {
630 return this.prevMark == mark;
631 }
632 }
634 boolean get(TypeSymbol origin) throws FunctionDescriptorLookupError {
635 Entry e = _map.get(origin);
636 CompoundScope members = membersClosure(origin.type, false);
637 if (e == null ||
638 !e.matches(members.getMark())) {
639 boolean isMarkerIntf = isMarkerInterfaceInternal(origin, members);
640 _map.put(origin, new Entry(isMarkerIntf, members.getMark()));
641 return isMarkerIntf;
642 }
643 else {
644 return e.isMarkerIntf;
645 }
646 }
648 /**
649 * Is given symbol a marker interface
650 */
651 public boolean isMarkerInterfaceInternal(TypeSymbol origin, CompoundScope membersCache) throws FunctionDescriptorLookupError {
652 return !origin.isInterface() ?
653 false :
654 !membersCache.getElements(new DescriptorFilter(origin)).iterator().hasNext();
655 }
656 }
658 private MarkerCache markerCache = new MarkerCache();
660 /**
661 * Is given type a marker interface?
662 */
663 public boolean isMarkerInterface(Type site) {
664 return markerCache.get(site.tsym);
665 }
666 // </editor-fold>
668 // <editor-fold defaultstate="collapsed" desc="isSubtype">
669 /**
670 * Is t an unchecked subtype of s?
671 */
672 public boolean isSubtypeUnchecked(Type t, Type s) {
673 return isSubtypeUnchecked(t, s, noWarnings);
674 }
675 /**
676 * Is t an unchecked subtype of s?
677 */
678 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
679 boolean result = isSubtypeUncheckedInternal(t, s, warn);
680 if (result) {
681 checkUnsafeVarargsConversion(t, s, warn);
682 }
683 return result;
684 }
685 //where
686 private boolean isSubtypeUncheckedInternal(Type t, Type s, Warner warn) {
687 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
688 t = t.unannotatedType();
689 s = s.unannotatedType();
690 if (((ArrayType)t).elemtype.isPrimitive()) {
691 return isSameType(elemtype(t), elemtype(s));
692 } else {
693 return isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
694 }
695 } else if (isSubtype(t, s)) {
696 return true;
697 }
698 else if (t.tag == TYPEVAR) {
699 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
700 }
701 else if (!s.isRaw()) {
702 Type t2 = asSuper(t, s.tsym);
703 if (t2 != null && t2.isRaw()) {
704 if (isReifiable(s))
705 warn.silentWarn(LintCategory.UNCHECKED);
706 else
707 warn.warn(LintCategory.UNCHECKED);
708 return true;
709 }
710 }
711 return false;
712 }
714 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
715 if (t.tag != ARRAY || isReifiable(t))
716 return;
717 t = t.unannotatedType();
718 s = s.unannotatedType();
719 ArrayType from = (ArrayType)t;
720 boolean shouldWarn = false;
721 switch (s.tag) {
722 case ARRAY:
723 ArrayType to = (ArrayType)s;
724 shouldWarn = from.isVarargs() &&
725 !to.isVarargs() &&
726 !isReifiable(from);
727 break;
728 case CLASS:
729 shouldWarn = from.isVarargs();
730 break;
731 }
732 if (shouldWarn) {
733 warn.warn(LintCategory.VARARGS);
734 }
735 }
737 /**
738 * Is t a subtype of s?<br>
739 * (not defined for Method and ForAll types)
740 */
741 final public boolean isSubtype(Type t, Type s) {
742 return isSubtype(t, s, true);
743 }
744 final public boolean isSubtypeNoCapture(Type t, Type s) {
745 return isSubtype(t, s, false);
746 }
747 public boolean isSubtype(Type t, Type s, boolean capture) {
748 if (t == s)
749 return true;
751 t = t.unannotatedType();
752 s = s.unannotatedType();
754 if (t == s)
755 return true;
757 if (s.isPartial())
758 return isSuperType(s, t);
760 if (s.isCompound()) {
761 for (Type s2 : interfaces(s).prepend(supertype(s))) {
762 if (!isSubtype(t, s2, capture))
763 return false;
764 }
765 return true;
766 }
768 Type lower = lowerBound(s);
769 if (s != lower)
770 return isSubtype(capture ? capture(t) : t, lower, false);
772 return isSubtype.visit(capture ? capture(t) : t, s);
773 }
774 // where
775 private TypeRelation isSubtype = new TypeRelation()
776 {
777 public Boolean visitType(Type t, Type s) {
778 switch (t.tag) {
779 case BYTE:
780 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
781 case CHAR:
782 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
783 case SHORT: case INT: case LONG:
784 case FLOAT: case DOUBLE:
785 return t.getTag().isSubRangeOf(s.getTag());
786 case BOOLEAN: case VOID:
787 return t.hasTag(s.getTag());
788 case TYPEVAR:
789 return isSubtypeNoCapture(t.getUpperBound(), s);
790 case BOT:
791 return
792 s.hasTag(BOT) || s.hasTag(CLASS) ||
793 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
794 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
795 case NONE:
796 return false;
797 default:
798 throw new AssertionError("isSubtype " + t.tag);
799 }
800 }
802 private Set<TypePair> cache = new HashSet<TypePair>();
804 private boolean containsTypeRecursive(Type t, Type s) {
805 TypePair pair = new TypePair(t, s);
806 if (cache.add(pair)) {
807 try {
808 return containsType(t.getTypeArguments(),
809 s.getTypeArguments());
810 } finally {
811 cache.remove(pair);
812 }
813 } else {
814 return containsType(t.getTypeArguments(),
815 rewriteSupers(s).getTypeArguments());
816 }
817 }
819 private Type rewriteSupers(Type t) {
820 if (!t.isParameterized())
821 return t;
822 ListBuffer<Type> from = lb();
823 ListBuffer<Type> to = lb();
824 adaptSelf(t, from, to);
825 if (from.isEmpty())
826 return t;
827 ListBuffer<Type> rewrite = lb();
828 boolean changed = false;
829 for (Type orig : to.toList()) {
830 Type s = rewriteSupers(orig);
831 if (s.isSuperBound() && !s.isExtendsBound()) {
832 s = new WildcardType(syms.objectType,
833 BoundKind.UNBOUND,
834 syms.boundClass);
835 changed = true;
836 } else if (s != orig) {
837 s = new WildcardType(upperBound(s),
838 BoundKind.EXTENDS,
839 syms.boundClass);
840 changed = true;
841 }
842 rewrite.append(s);
843 }
844 if (changed)
845 return subst(t.tsym.type, from.toList(), rewrite.toList());
846 else
847 return t;
848 }
850 @Override
851 public Boolean visitClassType(ClassType t, Type s) {
852 Type sup = asSuper(t, s.tsym);
853 return sup != null
854 && sup.tsym == s.tsym
855 // You're not allowed to write
856 // Vector<Object> vec = new Vector<String>();
857 // But with wildcards you can write
858 // Vector<? extends Object> vec = new Vector<String>();
859 // which means that subtype checking must be done
860 // here instead of same-type checking (via containsType).
861 && (!s.isParameterized() || containsTypeRecursive(s, sup))
862 && isSubtypeNoCapture(sup.getEnclosingType(),
863 s.getEnclosingType());
864 }
866 @Override
867 public Boolean visitArrayType(ArrayType t, Type s) {
868 if (s.tag == ARRAY) {
869 if (t.elemtype.isPrimitive())
870 return isSameType(t.elemtype, elemtype(s));
871 else
872 return isSubtypeNoCapture(t.elemtype, elemtype(s));
873 }
875 if (s.tag == CLASS) {
876 Name sname = s.tsym.getQualifiedName();
877 return sname == names.java_lang_Object
878 || sname == names.java_lang_Cloneable
879 || sname == names.java_io_Serializable;
880 }
882 return false;
883 }
885 @Override
886 public Boolean visitUndetVar(UndetVar t, Type s) {
887 //todo: test against origin needed? or replace with substitution?
888 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN) {
889 return true;
890 } else if (s.tag == BOT) {
891 //if 's' is 'null' there's no instantiated type U for which
892 //U <: s (but 'null' itself, which is not a valid type)
893 return false;
894 }
896 t.addBound(InferenceBound.UPPER, s, Types.this);
897 return true;
898 }
900 @Override
901 public Boolean visitErrorType(ErrorType t, Type s) {
902 return true;
903 }
904 };
906 /**
907 * Is t a subtype of every type in given list `ts'?<br>
908 * (not defined for Method and ForAll types)<br>
909 * Allows unchecked conversions.
910 */
911 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
912 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
913 if (!isSubtypeUnchecked(t, l.head, warn))
914 return false;
915 return true;
916 }
918 /**
919 * Are corresponding elements of ts subtypes of ss? If lists are
920 * of different length, return false.
921 */
922 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
923 while (ts.tail != null && ss.tail != null
924 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
925 isSubtype(ts.head, ss.head)) {
926 ts = ts.tail;
927 ss = ss.tail;
928 }
929 return ts.tail == null && ss.tail == null;
930 /*inlined: ts.isEmpty() && ss.isEmpty();*/
931 }
933 /**
934 * Are corresponding elements of ts subtypes of ss, allowing
935 * unchecked conversions? If lists are of different length,
936 * return false.
937 **/
938 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
939 while (ts.tail != null && ss.tail != null
940 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
941 isSubtypeUnchecked(ts.head, ss.head, warn)) {
942 ts = ts.tail;
943 ss = ss.tail;
944 }
945 return ts.tail == null && ss.tail == null;
946 /*inlined: ts.isEmpty() && ss.isEmpty();*/
947 }
948 // </editor-fold>
950 // <editor-fold defaultstate="collapsed" desc="isSuperType">
951 /**
952 * Is t a supertype of s?
953 */
954 public boolean isSuperType(Type t, Type s) {
955 switch (t.tag) {
956 case ERROR:
957 return true;
958 case UNDETVAR: {
959 UndetVar undet = (UndetVar)t;
960 if (t == s ||
961 undet.qtype == s ||
962 s.tag == ERROR ||
963 s.tag == BOT) return true;
964 undet.addBound(InferenceBound.LOWER, s, this);
965 return true;
966 }
967 default:
968 return isSubtype(s, t);
969 }
970 }
971 // </editor-fold>
973 // <editor-fold defaultstate="collapsed" desc="isSameType">
974 /**
975 * Are corresponding elements of the lists the same type? If
976 * lists are of different length, return false.
977 */
978 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
979 while (ts.tail != null && ss.tail != null
980 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
981 isSameType(ts.head, ss.head)) {
982 ts = ts.tail;
983 ss = ss.tail;
984 }
985 return ts.tail == null && ss.tail == null;
986 /*inlined: ts.isEmpty() && ss.isEmpty();*/
987 }
989 /**
990 * Is t the same type as s?
991 */
992 public boolean isSameType(Type t, Type s) {
993 return isSameType.visit(t, s);
994 }
995 // where
996 private TypeRelation isSameType = new TypeRelation() {
998 public Boolean visitType(Type t, Type s) {
999 if (t == s)
1000 return true;
1002 if (s.isPartial())
1003 return visit(s, t);
1005 switch (t.tag) {
1006 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1007 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
1008 return t.tag == s.tag;
1009 case TYPEVAR: {
1010 if (s.tag == TYPEVAR) {
1011 //type-substitution does not preserve type-var types
1012 //check that type var symbols and bounds are indeed the same
1013 return t.tsym == s.tsym &&
1014 visit(t.getUpperBound(), s.getUpperBound());
1015 }
1016 else {
1017 //special case for s == ? super X, where upper(s) = u
1018 //check that u == t, where u has been set by Type.withTypeVar
1019 return s.isSuperBound() &&
1020 !s.isExtendsBound() &&
1021 visit(t, upperBound(s));
1022 }
1023 }
1024 default:
1025 throw new AssertionError("isSameType " + t.tag);
1026 }
1027 }
1029 @Override
1030 public Boolean visitWildcardType(WildcardType t, Type s) {
1031 if (s.isPartial())
1032 return visit(s, t);
1033 else
1034 return false;
1035 }
1037 @Override
1038 public Boolean visitClassType(ClassType t, Type s) {
1039 if (t == s)
1040 return true;
1042 if (s.isPartial())
1043 return visit(s, t);
1045 if (s.isSuperBound() && !s.isExtendsBound())
1046 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
1048 if (t.isCompound() && s.isCompound()) {
1049 if (!visit(supertype(t), supertype(s)))
1050 return false;
1052 HashSet<UniqueType> set = new HashSet<UniqueType>();
1053 for (Type x : interfaces(t))
1054 set.add(new UniqueType(x, Types.this));
1055 for (Type x : interfaces(s)) {
1056 if (!set.remove(new UniqueType(x, Types.this)))
1057 return false;
1058 }
1059 return (set.isEmpty());
1060 }
1061 return t.tsym == s.tsym
1062 && visit(t.getEnclosingType(), s.getEnclosingType())
1063 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
1064 }
1066 @Override
1067 public Boolean visitArrayType(ArrayType t, Type s) {
1068 if (t == s)
1069 return true;
1071 if (s.isPartial())
1072 return visit(s, t);
1074 return s.hasTag(ARRAY)
1075 && containsTypeEquivalent(t.elemtype, elemtype(s));
1076 }
1078 @Override
1079 public Boolean visitMethodType(MethodType t, Type s) {
1080 // isSameType for methods does not take thrown
1081 // exceptions into account!
1082 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
1083 }
1085 @Override
1086 public Boolean visitPackageType(PackageType t, Type s) {
1087 return t == s;
1088 }
1090 @Override
1091 public Boolean visitForAll(ForAll t, Type s) {
1092 if (s.tag != FORALL)
1093 return false;
1095 ForAll forAll = (ForAll)s;
1096 return hasSameBounds(t, forAll)
1097 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1098 }
1100 @Override
1101 public Boolean visitUndetVar(UndetVar t, Type s) {
1102 if (s.tag == WILDCARD)
1103 // FIXME, this might be leftovers from before capture conversion
1104 return false;
1106 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
1107 return true;
1109 t.addBound(InferenceBound.EQ, s, Types.this);
1111 return true;
1112 }
1114 @Override
1115 public Boolean visitErrorType(ErrorType t, Type s) {
1116 return true;
1117 }
1118 };
1119 // </editor-fold>
1121 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1122 public boolean containedBy(Type t, Type s) {
1123 switch (t.tag) {
1124 case UNDETVAR:
1125 if (s.tag == WILDCARD) {
1126 UndetVar undetvar = (UndetVar)t;
1127 WildcardType wt = (WildcardType)s;
1128 switch(wt.kind) {
1129 case UNBOUND: //similar to ? extends Object
1130 case EXTENDS: {
1131 Type bound = upperBound(s);
1132 undetvar.addBound(InferenceBound.UPPER, bound, this);
1133 break;
1134 }
1135 case SUPER: {
1136 Type bound = lowerBound(s);
1137 undetvar.addBound(InferenceBound.LOWER, bound, this);
1138 break;
1139 }
1140 }
1141 return true;
1142 } else {
1143 return isSameType(t, s);
1144 }
1145 case ERROR:
1146 return true;
1147 default:
1148 return containsType(s, t);
1149 }
1150 }
1152 boolean containsType(List<Type> ts, List<Type> ss) {
1153 while (ts.nonEmpty() && ss.nonEmpty()
1154 && containsType(ts.head, ss.head)) {
1155 ts = ts.tail;
1156 ss = ss.tail;
1157 }
1158 return ts.isEmpty() && ss.isEmpty();
1159 }
1161 /**
1162 * Check if t contains s.
1163 *
1164 * <p>T contains S if:
1165 *
1166 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1167 *
1168 * <p>This relation is only used by ClassType.isSubtype(), that
1169 * is,
1170 *
1171 * <p>{@code C<S> <: C<T> if T contains S.}
1172 *
1173 * <p>Because of F-bounds, this relation can lead to infinite
1174 * recursion. Thus we must somehow break that recursion. Notice
1175 * that containsType() is only called from ClassType.isSubtype().
1176 * Since the arguments have already been checked against their
1177 * bounds, we know:
1178 *
1179 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1180 *
1181 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1182 *
1183 * @param t a type
1184 * @param s a type
1185 */
1186 public boolean containsType(Type t, Type s) {
1187 return containsType.visit(t, s);
1188 }
1189 // where
1190 private TypeRelation containsType = new TypeRelation() {
1192 private Type U(Type t) {
1193 while (t.tag == WILDCARD) {
1194 WildcardType w = (WildcardType)t;
1195 if (w.isSuperBound())
1196 return w.bound == null ? syms.objectType : w.bound.bound;
1197 else
1198 t = w.type;
1199 }
1200 return t;
1201 }
1203 private Type L(Type t) {
1204 while (t.tag == WILDCARD) {
1205 WildcardType w = (WildcardType)t;
1206 if (w.isExtendsBound())
1207 return syms.botType;
1208 else
1209 t = w.type;
1210 }
1211 return t;
1212 }
1214 public Boolean visitType(Type t, Type s) {
1215 if (s.isPartial())
1216 return containedBy(s, t);
1217 else
1218 return isSameType(t, s);
1219 }
1221 // void debugContainsType(WildcardType t, Type s) {
1222 // System.err.println();
1223 // System.err.format(" does %s contain %s?%n", t, s);
1224 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1225 // upperBound(s), s, t, U(t),
1226 // t.isSuperBound()
1227 // || isSubtypeNoCapture(upperBound(s), U(t)));
1228 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1229 // L(t), t, s, lowerBound(s),
1230 // t.isExtendsBound()
1231 // || isSubtypeNoCapture(L(t), lowerBound(s)));
1232 // System.err.println();
1233 // }
1235 @Override
1236 public Boolean visitWildcardType(WildcardType t, Type s) {
1237 if (s.isPartial())
1238 return containedBy(s, t);
1239 else {
1240 // debugContainsType(t, s);
1241 return isSameWildcard(t, s)
1242 || isCaptureOf(s, t)
1243 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
1244 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
1245 }
1246 }
1248 @Override
1249 public Boolean visitUndetVar(UndetVar t, Type s) {
1250 if (s.tag != WILDCARD)
1251 return isSameType(t, s);
1252 else
1253 return false;
1254 }
1256 @Override
1257 public Boolean visitErrorType(ErrorType t, Type s) {
1258 return true;
1259 }
1260 };
1262 public boolean isCaptureOf(Type s, WildcardType t) {
1263 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
1264 return false;
1265 return isSameWildcard(t, ((CapturedType)s).wildcard);
1266 }
1268 public boolean isSameWildcard(WildcardType t, Type s) {
1269 if (s.tag != WILDCARD)
1270 return false;
1271 WildcardType w = (WildcardType)s;
1272 return w.kind == t.kind && w.type == t.type;
1273 }
1275 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1276 while (ts.nonEmpty() && ss.nonEmpty()
1277 && containsTypeEquivalent(ts.head, ss.head)) {
1278 ts = ts.tail;
1279 ss = ss.tail;
1280 }
1281 return ts.isEmpty() && ss.isEmpty();
1282 }
1283 // </editor-fold>
1285 // <editor-fold defaultstate="collapsed" desc="isCastable">
1286 public boolean isCastable(Type t, Type s) {
1287 return isCastable(t, s, noWarnings);
1288 }
1290 /**
1291 * Is t is castable to s?<br>
1292 * s is assumed to be an erased type.<br>
1293 * (not defined for Method and ForAll types).
1294 */
1295 public boolean isCastable(Type t, Type s, Warner warn) {
1296 if (t == s)
1297 return true;
1299 if (t.isPrimitive() != s.isPrimitive())
1300 return allowBoxing && (
1301 isConvertible(t, s, warn)
1302 || (allowObjectToPrimitiveCast &&
1303 s.isPrimitive() &&
1304 isSubtype(boxedClass(s).type, t)));
1305 if (warn != warnStack.head) {
1306 try {
1307 warnStack = warnStack.prepend(warn);
1308 checkUnsafeVarargsConversion(t, s, warn);
1309 return isCastable.visit(t,s);
1310 } finally {
1311 warnStack = warnStack.tail;
1312 }
1313 } else {
1314 return isCastable.visit(t,s);
1315 }
1316 }
1317 // where
1318 private TypeRelation isCastable = new TypeRelation() {
1320 public Boolean visitType(Type t, Type s) {
1321 if (s.tag == ERROR)
1322 return true;
1324 switch (t.tag) {
1325 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1326 case DOUBLE:
1327 return s.isNumeric();
1328 case BOOLEAN:
1329 return s.tag == BOOLEAN;
1330 case VOID:
1331 return false;
1332 case BOT:
1333 return isSubtype(t, s);
1334 default:
1335 throw new AssertionError();
1336 }
1337 }
1339 @Override
1340 public Boolean visitWildcardType(WildcardType t, Type s) {
1341 return isCastable(upperBound(t), s, warnStack.head);
1342 }
1344 @Override
1345 public Boolean visitClassType(ClassType t, Type s) {
1346 if (s.tag == ERROR || s.tag == BOT)
1347 return true;
1349 if (s.tag == TYPEVAR) {
1350 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1351 warnStack.head.warn(LintCategory.UNCHECKED);
1352 return true;
1353 } else {
1354 return false;
1355 }
1356 }
1358 if (t.isCompound()) {
1359 Warner oldWarner = warnStack.head;
1360 warnStack.head = noWarnings;
1361 if (!visit(supertype(t), s))
1362 return false;
1363 for (Type intf : interfaces(t)) {
1364 if (!visit(intf, s))
1365 return false;
1366 }
1367 if (warnStack.head.hasLint(LintCategory.UNCHECKED))
1368 oldWarner.warn(LintCategory.UNCHECKED);
1369 return true;
1370 }
1372 if (s.isCompound()) {
1373 // call recursively to reuse the above code
1374 return visitClassType((ClassType)s, t);
1375 }
1377 if (s.tag == CLASS || s.tag == ARRAY) {
1378 boolean upcast;
1379 if ((upcast = isSubtype(erasure(t), erasure(s)))
1380 || isSubtype(erasure(s), erasure(t))) {
1381 if (!upcast && s.tag == ARRAY) {
1382 if (!isReifiable(s))
1383 warnStack.head.warn(LintCategory.UNCHECKED);
1384 return true;
1385 } else if (s.isRaw()) {
1386 return true;
1387 } else if (t.isRaw()) {
1388 if (!isUnbounded(s))
1389 warnStack.head.warn(LintCategory.UNCHECKED);
1390 return true;
1391 }
1392 // Assume |a| <: |b|
1393 final Type a = upcast ? t : s;
1394 final Type b = upcast ? s : t;
1395 final boolean HIGH = true;
1396 final boolean LOW = false;
1397 final boolean DONT_REWRITE_TYPEVARS = false;
1398 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1399 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1400 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1401 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1402 Type lowSub = asSub(bLow, aLow.tsym);
1403 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1404 if (highSub == null) {
1405 final boolean REWRITE_TYPEVARS = true;
1406 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1407 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1408 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1409 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1410 lowSub = asSub(bLow, aLow.tsym);
1411 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1412 }
1413 if (highSub != null) {
1414 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1415 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1416 }
1417 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1418 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1419 && !disjointTypes(aLow.allparams(), highSub.allparams())
1420 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1421 if (upcast ? giveWarning(a, b) :
1422 giveWarning(b, a))
1423 warnStack.head.warn(LintCategory.UNCHECKED);
1424 return true;
1425 }
1426 }
1427 if (isReifiable(s))
1428 return isSubtypeUnchecked(a, b);
1429 else
1430 return isSubtypeUnchecked(a, b, warnStack.head);
1431 }
1433 // Sidecast
1434 if (s.tag == CLASS) {
1435 if ((s.tsym.flags() & INTERFACE) != 0) {
1436 return ((t.tsym.flags() & FINAL) == 0)
1437 ? sideCast(t, s, warnStack.head)
1438 : sideCastFinal(t, s, warnStack.head);
1439 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1440 return ((s.tsym.flags() & FINAL) == 0)
1441 ? sideCast(t, s, warnStack.head)
1442 : sideCastFinal(t, s, warnStack.head);
1443 } else {
1444 // unrelated class types
1445 return false;
1446 }
1447 }
1448 }
1449 return false;
1450 }
1452 @Override
1453 public Boolean visitArrayType(ArrayType t, Type s) {
1454 switch (s.tag) {
1455 case ERROR:
1456 case BOT:
1457 return true;
1458 case TYPEVAR:
1459 if (isCastable(s, t, noWarnings)) {
1460 warnStack.head.warn(LintCategory.UNCHECKED);
1461 return true;
1462 } else {
1463 return false;
1464 }
1465 case CLASS:
1466 return isSubtype(t, s);
1467 case ARRAY:
1468 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1469 return elemtype(t).tag == elemtype(s).tag;
1470 } else {
1471 return visit(elemtype(t), elemtype(s));
1472 }
1473 default:
1474 return false;
1475 }
1476 }
1478 @Override
1479 public Boolean visitTypeVar(TypeVar t, Type s) {
1480 switch (s.tag) {
1481 case ERROR:
1482 case BOT:
1483 return true;
1484 case TYPEVAR:
1485 if (isSubtype(t, s)) {
1486 return true;
1487 } else if (isCastable(t.bound, s, noWarnings)) {
1488 warnStack.head.warn(LintCategory.UNCHECKED);
1489 return true;
1490 } else {
1491 return false;
1492 }
1493 default:
1494 return isCastable(t.bound, s, warnStack.head);
1495 }
1496 }
1498 @Override
1499 public Boolean visitErrorType(ErrorType t, Type s) {
1500 return true;
1501 }
1502 };
1503 // </editor-fold>
1505 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1506 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1507 while (ts.tail != null && ss.tail != null) {
1508 if (disjointType(ts.head, ss.head)) return true;
1509 ts = ts.tail;
1510 ss = ss.tail;
1511 }
1512 return false;
1513 }
1515 /**
1516 * Two types or wildcards are considered disjoint if it can be
1517 * proven that no type can be contained in both. It is
1518 * conservative in that it is allowed to say that two types are
1519 * not disjoint, even though they actually are.
1520 *
1521 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1522 * {@code X} and {@code Y} are not disjoint.
1523 */
1524 public boolean disjointType(Type t, Type s) {
1525 return disjointType.visit(t, s);
1526 }
1527 // where
1528 private TypeRelation disjointType = new TypeRelation() {
1530 private Set<TypePair> cache = new HashSet<TypePair>();
1532 public Boolean visitType(Type t, Type s) {
1533 if (s.tag == WILDCARD)
1534 return visit(s, t);
1535 else
1536 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1537 }
1539 private boolean isCastableRecursive(Type t, Type s) {
1540 TypePair pair = new TypePair(t, s);
1541 if (cache.add(pair)) {
1542 try {
1543 return Types.this.isCastable(t, s);
1544 } finally {
1545 cache.remove(pair);
1546 }
1547 } else {
1548 return true;
1549 }
1550 }
1552 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1553 TypePair pair = new TypePair(t, s);
1554 if (cache.add(pair)) {
1555 try {
1556 return Types.this.notSoftSubtype(t, s);
1557 } finally {
1558 cache.remove(pair);
1559 }
1560 } else {
1561 return false;
1562 }
1563 }
1565 @Override
1566 public Boolean visitWildcardType(WildcardType t, Type s) {
1567 if (t.isUnbound())
1568 return false;
1570 if (s.tag != WILDCARD) {
1571 if (t.isExtendsBound())
1572 return notSoftSubtypeRecursive(s, t.type);
1573 else // isSuperBound()
1574 return notSoftSubtypeRecursive(t.type, s);
1575 }
1577 if (s.isUnbound())
1578 return false;
1580 if (t.isExtendsBound()) {
1581 if (s.isExtendsBound())
1582 return !isCastableRecursive(t.type, upperBound(s));
1583 else if (s.isSuperBound())
1584 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1585 } else if (t.isSuperBound()) {
1586 if (s.isExtendsBound())
1587 return notSoftSubtypeRecursive(t.type, upperBound(s));
1588 }
1589 return false;
1590 }
1591 };
1592 // </editor-fold>
1594 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1595 /**
1596 * Returns the lower bounds of the formals of a method.
1597 */
1598 public List<Type> lowerBoundArgtypes(Type t) {
1599 return lowerBounds(t.getParameterTypes());
1600 }
1601 public List<Type> lowerBounds(List<Type> ts) {
1602 return map(ts, lowerBoundMapping);
1603 }
1604 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1605 public Type apply(Type t) {
1606 return lowerBound(t);
1607 }
1608 };
1609 // </editor-fold>
1611 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1612 /**
1613 * This relation answers the question: is impossible that
1614 * something of type `t' can be a subtype of `s'? This is
1615 * different from the question "is `t' not a subtype of `s'?"
1616 * when type variables are involved: Integer is not a subtype of T
1617 * where {@code <T extends Number>} but it is not true that Integer cannot
1618 * possibly be a subtype of T.
1619 */
1620 public boolean notSoftSubtype(Type t, Type s) {
1621 if (t == s) return false;
1622 if (t.tag == TYPEVAR) {
1623 TypeVar tv = (TypeVar) t;
1624 return !isCastable(tv.bound,
1625 relaxBound(s),
1626 noWarnings);
1627 }
1628 if (s.tag != WILDCARD)
1629 s = upperBound(s);
1631 return !isSubtype(t, relaxBound(s));
1632 }
1634 private Type relaxBound(Type t) {
1635 if (t.tag == TYPEVAR) {
1636 while (t.tag == TYPEVAR)
1637 t = t.getUpperBound();
1638 t = rewriteQuantifiers(t, true, true);
1639 }
1640 return t;
1641 }
1642 // </editor-fold>
1644 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1645 public boolean isReifiable(Type t) {
1646 return isReifiable.visit(t);
1647 }
1648 // where
1649 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1651 public Boolean visitType(Type t, Void ignored) {
1652 return true;
1653 }
1655 @Override
1656 public Boolean visitClassType(ClassType t, Void ignored) {
1657 if (t.isCompound())
1658 return false;
1659 else {
1660 if (!t.isParameterized())
1661 return true;
1663 for (Type param : t.allparams()) {
1664 if (!param.isUnbound())
1665 return false;
1666 }
1667 return true;
1668 }
1669 }
1671 @Override
1672 public Boolean visitArrayType(ArrayType t, Void ignored) {
1673 return visit(t.elemtype);
1674 }
1676 @Override
1677 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1678 return false;
1679 }
1680 };
1681 // </editor-fold>
1683 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1684 public boolean isArray(Type t) {
1685 while (t.tag == WILDCARD)
1686 t = upperBound(t);
1687 return t.tag == ARRAY;
1688 }
1690 /**
1691 * The element type of an array.
1692 */
1693 public Type elemtype(Type t) {
1694 switch (t.tag) {
1695 case WILDCARD:
1696 return elemtype(upperBound(t));
1697 case ARRAY:
1698 t = t.unannotatedType();
1699 return ((ArrayType)t).elemtype;
1700 case FORALL:
1701 return elemtype(((ForAll)t).qtype);
1702 case ERROR:
1703 return t;
1704 default:
1705 return null;
1706 }
1707 }
1709 public Type elemtypeOrType(Type t) {
1710 Type elemtype = elemtype(t);
1711 return elemtype != null ?
1712 elemtype :
1713 t;
1714 }
1716 /**
1717 * Mapping to take element type of an arraytype
1718 */
1719 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1720 public Type apply(Type t) { return elemtype(t); }
1721 };
1723 /**
1724 * The number of dimensions of an array type.
1725 */
1726 public int dimensions(Type t) {
1727 int result = 0;
1728 while (t.tag == ARRAY) {
1729 result++;
1730 t = elemtype(t);
1731 }
1732 return result;
1733 }
1735 /**
1736 * Returns an ArrayType with the component type t
1737 *
1738 * @param t The component type of the ArrayType
1739 * @return the ArrayType for the given component
1740 */
1741 public ArrayType makeArrayType(Type t) {
1742 if (t.tag == VOID ||
1743 t.tag == PACKAGE) {
1744 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
1745 }
1746 return new ArrayType(t, syms.arrayClass);
1747 }
1748 // </editor-fold>
1750 // <editor-fold defaultstate="collapsed" desc="asSuper">
1751 /**
1752 * Return the (most specific) base type of t that starts with the
1753 * given symbol. If none exists, return null.
1754 *
1755 * @param t a type
1756 * @param sym a symbol
1757 */
1758 public Type asSuper(Type t, Symbol sym) {
1759 return asSuper.visit(t, sym);
1760 }
1761 // where
1762 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1764 public Type visitType(Type t, Symbol sym) {
1765 return null;
1766 }
1768 @Override
1769 public Type visitClassType(ClassType t, Symbol sym) {
1770 if (t.tsym == sym)
1771 return t;
1773 Type st = supertype(t);
1774 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1775 Type x = asSuper(st, sym);
1776 if (x != null)
1777 return x;
1778 }
1779 if ((sym.flags() & INTERFACE) != 0) {
1780 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1781 Type x = asSuper(l.head, sym);
1782 if (x != null)
1783 return x;
1784 }
1785 }
1786 return null;
1787 }
1789 @Override
1790 public Type visitArrayType(ArrayType t, Symbol sym) {
1791 return isSubtype(t, sym.type) ? sym.type : null;
1792 }
1794 @Override
1795 public Type visitTypeVar(TypeVar t, Symbol sym) {
1796 if (t.tsym == sym)
1797 return t;
1798 else
1799 return asSuper(t.bound, sym);
1800 }
1802 @Override
1803 public Type visitErrorType(ErrorType t, Symbol sym) {
1804 return t;
1805 }
1806 };
1808 /**
1809 * Return the base type of t or any of its outer types that starts
1810 * with the given symbol. If none exists, return null.
1811 *
1812 * @param t a type
1813 * @param sym a symbol
1814 */
1815 public Type asOuterSuper(Type t, Symbol sym) {
1816 switch (t.tag) {
1817 case CLASS:
1818 do {
1819 Type s = asSuper(t, sym);
1820 if (s != null) return s;
1821 t = t.getEnclosingType();
1822 } while (t.tag == CLASS);
1823 return null;
1824 case ARRAY:
1825 return isSubtype(t, sym.type) ? sym.type : null;
1826 case TYPEVAR:
1827 return asSuper(t, sym);
1828 case ERROR:
1829 return t;
1830 default:
1831 return null;
1832 }
1833 }
1835 /**
1836 * Return the base type of t or any of its enclosing types that
1837 * starts with the given symbol. If none exists, return null.
1838 *
1839 * @param t a type
1840 * @param sym a symbol
1841 */
1842 public Type asEnclosingSuper(Type t, Symbol sym) {
1843 switch (t.tag) {
1844 case CLASS:
1845 do {
1846 Type s = asSuper(t, sym);
1847 if (s != null) return s;
1848 Type outer = t.getEnclosingType();
1849 t = (outer.tag == CLASS) ? outer :
1850 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1851 Type.noType;
1852 } while (t.tag == CLASS);
1853 return null;
1854 case ARRAY:
1855 return isSubtype(t, sym.type) ? sym.type : null;
1856 case TYPEVAR:
1857 return asSuper(t, sym);
1858 case ERROR:
1859 return t;
1860 default:
1861 return null;
1862 }
1863 }
1864 // </editor-fold>
1866 // <editor-fold defaultstate="collapsed" desc="memberType">
1867 /**
1868 * The type of given symbol, seen as a member of t.
1869 *
1870 * @param t a type
1871 * @param sym a symbol
1872 */
1873 public Type memberType(Type t, Symbol sym) {
1874 return (sym.flags() & STATIC) != 0
1875 ? sym.type
1876 : memberType.visit(t, sym);
1877 }
1878 // where
1879 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1881 public Type visitType(Type t, Symbol sym) {
1882 return sym.type;
1883 }
1885 @Override
1886 public Type visitWildcardType(WildcardType t, Symbol sym) {
1887 return memberType(upperBound(t), sym);
1888 }
1890 @Override
1891 public Type visitClassType(ClassType t, Symbol sym) {
1892 Symbol owner = sym.owner;
1893 long flags = sym.flags();
1894 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1895 Type base = asOuterSuper(t, owner);
1896 //if t is an intersection type T = CT & I1 & I2 ... & In
1897 //its supertypes CT, I1, ... In might contain wildcards
1898 //so we need to go through capture conversion
1899 base = t.isCompound() ? capture(base) : base;
1900 if (base != null) {
1901 List<Type> ownerParams = owner.type.allparams();
1902 List<Type> baseParams = base.allparams();
1903 if (ownerParams.nonEmpty()) {
1904 if (baseParams.isEmpty()) {
1905 // then base is a raw type
1906 return erasure(sym.type);
1907 } else {
1908 return subst(sym.type, ownerParams, baseParams);
1909 }
1910 }
1911 }
1912 }
1913 return sym.type;
1914 }
1916 @Override
1917 public Type visitTypeVar(TypeVar t, Symbol sym) {
1918 return memberType(t.bound, sym);
1919 }
1921 @Override
1922 public Type visitErrorType(ErrorType t, Symbol sym) {
1923 return t;
1924 }
1925 };
1926 // </editor-fold>
1928 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1929 public boolean isAssignable(Type t, Type s) {
1930 return isAssignable(t, s, noWarnings);
1931 }
1933 /**
1934 * Is t assignable to s?<br>
1935 * Equivalent to subtype except for constant values and raw
1936 * types.<br>
1937 * (not defined for Method and ForAll types)
1938 */
1939 public boolean isAssignable(Type t, Type s, Warner warn) {
1940 if (t.tag == ERROR)
1941 return true;
1942 if (t.tag.isSubRangeOf(INT) && t.constValue() != null) {
1943 int value = ((Number)t.constValue()).intValue();
1944 switch (s.tag) {
1945 case BYTE:
1946 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1947 return true;
1948 break;
1949 case CHAR:
1950 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1951 return true;
1952 break;
1953 case SHORT:
1954 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1955 return true;
1956 break;
1957 case INT:
1958 return true;
1959 case CLASS:
1960 switch (unboxedType(s).tag) {
1961 case BYTE:
1962 case CHAR:
1963 case SHORT:
1964 return isAssignable(t, unboxedType(s), warn);
1965 }
1966 break;
1967 }
1968 }
1969 return isConvertible(t, s, warn);
1970 }
1971 // </editor-fold>
1973 // <editor-fold defaultstate="collapsed" desc="erasure">
1974 /**
1975 * The erasure of t {@code |t|} -- the type that results when all
1976 * type parameters in t are deleted.
1977 */
1978 public Type erasure(Type t) {
1979 return eraseNotNeeded(t)? t : erasure(t, false);
1980 }
1981 //where
1982 private boolean eraseNotNeeded(Type t) {
1983 // We don't want to erase primitive types and String type as that
1984 // operation is idempotent. Also, erasing these could result in loss
1985 // of information such as constant values attached to such types.
1986 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
1987 }
1989 private Type erasure(Type t, boolean recurse) {
1990 if (t.isPrimitive())
1991 return t; /* fast special case */
1992 else
1993 return erasure.visit(t, recurse);
1994 }
1995 // where
1996 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
1997 public Type visitType(Type t, Boolean recurse) {
1998 if (t.isPrimitive())
1999 return t; /*fast special case*/
2000 else
2001 return t.map(recurse ? erasureRecFun : erasureFun);
2002 }
2004 @Override
2005 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2006 return erasure(upperBound(t), recurse);
2007 }
2009 @Override
2010 public Type visitClassType(ClassType t, Boolean recurse) {
2011 Type erased = t.tsym.erasure(Types.this);
2012 if (recurse) {
2013 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
2014 }
2015 return erased;
2016 }
2018 @Override
2019 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2020 return erasure(t.bound, recurse);
2021 }
2023 @Override
2024 public Type visitErrorType(ErrorType t, Boolean recurse) {
2025 return t;
2026 }
2028 @Override
2029 public Type visitAnnotatedType(AnnotatedType t, Boolean recurse) {
2030 return new AnnotatedType(t.typeAnnotations, erasure(t.underlyingType, recurse));
2031 }
2032 };
2034 private Mapping erasureFun = new Mapping ("erasure") {
2035 public Type apply(Type t) { return erasure(t); }
2036 };
2038 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
2039 public Type apply(Type t) { return erasureRecursive(t); }
2040 };
2042 public List<Type> erasure(List<Type> ts) {
2043 return Type.map(ts, erasureFun);
2044 }
2046 public Type erasureRecursive(Type t) {
2047 return erasure(t, true);
2048 }
2050 public List<Type> erasureRecursive(List<Type> ts) {
2051 return Type.map(ts, erasureRecFun);
2052 }
2053 // </editor-fold>
2055 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
2056 /**
2057 * Make a compound type from non-empty list of types
2058 *
2059 * @param bounds the types from which the compound type is formed
2060 * @param supertype is objectType if all bounds are interfaces,
2061 * null otherwise.
2062 */
2063 public Type makeCompoundType(List<Type> bounds) {
2064 return makeCompoundType(bounds, bounds.head.tsym.isInterface());
2065 }
2066 public Type makeCompoundType(List<Type> bounds, boolean allInterfaces) {
2067 Assert.check(bounds.nonEmpty());
2068 Type firstExplicitBound = bounds.head;
2069 if (allInterfaces) {
2070 bounds = bounds.prepend(syms.objectType);
2071 }
2072 ClassSymbol bc =
2073 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2074 Type.moreInfo
2075 ? names.fromString(bounds.toString())
2076 : names.empty,
2077 null,
2078 syms.noSymbol);
2079 bc.type = new IntersectionClassType(bounds, bc, allInterfaces);
2080 bc.erasure_field = (bounds.head.tag == TYPEVAR) ?
2081 syms.objectType : // error condition, recover
2082 erasure(firstExplicitBound);
2083 bc.members_field = new Scope(bc);
2084 return bc.type;
2085 }
2087 /**
2088 * A convenience wrapper for {@link #makeCompoundType(List)}; the
2089 * arguments are converted to a list and passed to the other
2090 * method. Note that this might cause a symbol completion.
2091 * Hence, this version of makeCompoundType may not be called
2092 * during a classfile read.
2093 */
2094 public Type makeCompoundType(Type bound1, Type bound2) {
2095 return makeCompoundType(List.of(bound1, bound2));
2096 }
2097 // </editor-fold>
2099 // <editor-fold defaultstate="collapsed" desc="supertype">
2100 public Type supertype(Type t) {
2101 return supertype.visit(t);
2102 }
2103 // where
2104 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2106 public Type visitType(Type t, Void ignored) {
2107 // A note on wildcards: there is no good way to
2108 // determine a supertype for a super bounded wildcard.
2109 return null;
2110 }
2112 @Override
2113 public Type visitClassType(ClassType t, Void ignored) {
2114 if (t.supertype_field == null) {
2115 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2116 // An interface has no superclass; its supertype is Object.
2117 if (t.isInterface())
2118 supertype = ((ClassType)t.tsym.type).supertype_field;
2119 if (t.supertype_field == null) {
2120 List<Type> actuals = classBound(t).allparams();
2121 List<Type> formals = t.tsym.type.allparams();
2122 if (t.hasErasedSupertypes()) {
2123 t.supertype_field = erasureRecursive(supertype);
2124 } else if (formals.nonEmpty()) {
2125 t.supertype_field = subst(supertype, formals, actuals);
2126 }
2127 else {
2128 t.supertype_field = supertype;
2129 }
2130 }
2131 }
2132 return t.supertype_field;
2133 }
2135 /**
2136 * The supertype is always a class type. If the type
2137 * variable's bounds start with a class type, this is also
2138 * the supertype. Otherwise, the supertype is
2139 * java.lang.Object.
2140 */
2141 @Override
2142 public Type visitTypeVar(TypeVar t, Void ignored) {
2143 if (t.bound.tag == TYPEVAR ||
2144 (!t.bound.isCompound() && !t.bound.isInterface())) {
2145 return t.bound;
2146 } else {
2147 return supertype(t.bound);
2148 }
2149 }
2151 @Override
2152 public Type visitArrayType(ArrayType t, Void ignored) {
2153 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2154 return arraySuperType();
2155 else
2156 return new ArrayType(supertype(t.elemtype), t.tsym);
2157 }
2159 @Override
2160 public Type visitErrorType(ErrorType t, Void ignored) {
2161 return t;
2162 }
2163 };
2164 // </editor-fold>
2166 // <editor-fold defaultstate="collapsed" desc="interfaces">
2167 /**
2168 * Return the interfaces implemented by this class.
2169 */
2170 public List<Type> interfaces(Type t) {
2171 return interfaces.visit(t);
2172 }
2173 // where
2174 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2176 public List<Type> visitType(Type t, Void ignored) {
2177 return List.nil();
2178 }
2180 @Override
2181 public List<Type> visitClassType(ClassType t, Void ignored) {
2182 if (t.interfaces_field == null) {
2183 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2184 if (t.interfaces_field == null) {
2185 // If t.interfaces_field is null, then t must
2186 // be a parameterized type (not to be confused
2187 // with a generic type declaration).
2188 // Terminology:
2189 // Parameterized type: List<String>
2190 // Generic type declaration: class List<E> { ... }
2191 // So t corresponds to List<String> and
2192 // t.tsym.type corresponds to List<E>.
2193 // The reason t must be parameterized type is
2194 // that completion will happen as a side
2195 // effect of calling
2196 // ClassSymbol.getInterfaces. Since
2197 // t.interfaces_field is null after
2198 // completion, we can assume that t is not the
2199 // type of a class/interface declaration.
2200 Assert.check(t != t.tsym.type, t);
2201 List<Type> actuals = t.allparams();
2202 List<Type> formals = t.tsym.type.allparams();
2203 if (t.hasErasedSupertypes()) {
2204 t.interfaces_field = erasureRecursive(interfaces);
2205 } else if (formals.nonEmpty()) {
2206 t.interfaces_field =
2207 upperBounds(subst(interfaces, formals, actuals));
2208 }
2209 else {
2210 t.interfaces_field = interfaces;
2211 }
2212 }
2213 }
2214 return t.interfaces_field;
2215 }
2217 @Override
2218 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2219 if (t.bound.isCompound())
2220 return interfaces(t.bound);
2222 if (t.bound.isInterface())
2223 return List.of(t.bound);
2225 return List.nil();
2226 }
2227 };
2229 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2230 for (Type i2 : interfaces(origin.type)) {
2231 if (isym == i2.tsym) return true;
2232 }
2233 return false;
2234 }
2235 // </editor-fold>
2237 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2238 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
2240 public boolean isDerivedRaw(Type t) {
2241 Boolean result = isDerivedRawCache.get(t);
2242 if (result == null) {
2243 result = isDerivedRawInternal(t);
2244 isDerivedRawCache.put(t, result);
2245 }
2246 return result;
2247 }
2249 public boolean isDerivedRawInternal(Type t) {
2250 if (t.isErroneous())
2251 return false;
2252 return
2253 t.isRaw() ||
2254 supertype(t) != null && isDerivedRaw(supertype(t)) ||
2255 isDerivedRaw(interfaces(t));
2256 }
2258 public boolean isDerivedRaw(List<Type> ts) {
2259 List<Type> l = ts;
2260 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2261 return l.nonEmpty();
2262 }
2263 // </editor-fold>
2265 // <editor-fold defaultstate="collapsed" desc="setBounds">
2266 /**
2267 * Set the bounds field of the given type variable to reflect a
2268 * (possibly multiple) list of bounds.
2269 * @param t a type variable
2270 * @param bounds the bounds, must be nonempty
2271 * @param supertype is objectType if all bounds are interfaces,
2272 * null otherwise.
2273 */
2274 public void setBounds(TypeVar t, List<Type> bounds) {
2275 setBounds(t, bounds, bounds.head.tsym.isInterface());
2276 }
2278 /**
2279 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
2280 * third parameter is computed directly, as follows: if all
2281 * all bounds are interface types, the computed supertype is Object,
2282 * otherwise the supertype is simply left null (in this case, the supertype
2283 * is assumed to be the head of the bound list passed as second argument).
2284 * Note that this check might cause a symbol completion. Hence, this version of
2285 * setBounds may not be called during a classfile read.
2286 */
2287 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2288 t.bound = bounds.tail.isEmpty() ?
2289 bounds.head :
2290 makeCompoundType(bounds, allInterfaces);
2291 t.rank_field = -1;
2292 }
2293 // </editor-fold>
2295 // <editor-fold defaultstate="collapsed" desc="getBounds">
2296 /**
2297 * Return list of bounds of the given type variable.
2298 */
2299 public List<Type> getBounds(TypeVar t) {
2300 if (t.bound.hasTag(NONE))
2301 return List.nil();
2302 else if (t.bound.isErroneous() || !t.bound.isCompound())
2303 return List.of(t.bound);
2304 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2305 return interfaces(t).prepend(supertype(t));
2306 else
2307 // No superclass was given in bounds.
2308 // In this case, supertype is Object, erasure is first interface.
2309 return interfaces(t);
2310 }
2311 // </editor-fold>
2313 // <editor-fold defaultstate="collapsed" desc="classBound">
2314 /**
2315 * If the given type is a (possibly selected) type variable,
2316 * return the bounding class of this type, otherwise return the
2317 * type itself.
2318 */
2319 public Type classBound(Type t) {
2320 return classBound.visit(t);
2321 }
2322 // where
2323 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2325 public Type visitType(Type t, Void ignored) {
2326 return t;
2327 }
2329 @Override
2330 public Type visitClassType(ClassType t, Void ignored) {
2331 Type outer1 = classBound(t.getEnclosingType());
2332 if (outer1 != t.getEnclosingType())
2333 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
2334 else
2335 return t;
2336 }
2338 @Override
2339 public Type visitTypeVar(TypeVar t, Void ignored) {
2340 return classBound(supertype(t));
2341 }
2343 @Override
2344 public Type visitErrorType(ErrorType t, Void ignored) {
2345 return t;
2346 }
2347 };
2348 // </editor-fold>
2350 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
2351 /**
2352 * Returns true iff the first signature is a <em>sub
2353 * signature</em> of the other. This is <b>not</b> an equivalence
2354 * relation.
2355 *
2356 * @jls section 8.4.2.
2357 * @see #overrideEquivalent(Type t, Type s)
2358 * @param t first signature (possibly raw).
2359 * @param s second signature (could be subjected to erasure).
2360 * @return true if t is a sub signature of s.
2361 */
2362 public boolean isSubSignature(Type t, Type s) {
2363 return isSubSignature(t, s, true);
2364 }
2366 public boolean isSubSignature(Type t, Type s, boolean strict) {
2367 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2368 }
2370 /**
2371 * Returns true iff these signatures are related by <em>override
2372 * equivalence</em>. This is the natural extension of
2373 * isSubSignature to an equivalence relation.
2374 *
2375 * @jls section 8.4.2.
2376 * @see #isSubSignature(Type t, Type s)
2377 * @param t a signature (possible raw, could be subjected to
2378 * erasure).
2379 * @param s a signature (possible raw, could be subjected to
2380 * erasure).
2381 * @return true if either argument is a sub signature of the other.
2382 */
2383 public boolean overrideEquivalent(Type t, Type s) {
2384 return hasSameArgs(t, s) ||
2385 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2386 }
2388 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2389 for (Scope.Entry e = syms.objectType.tsym.members().lookup(msym.name) ; e.scope != null ; e = e.next()) {
2390 if (msym.overrides(e.sym, origin, Types.this, true)) {
2391 return true;
2392 }
2393 }
2394 return false;
2395 }
2397 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2398 class ImplementationCache {
2400 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
2401 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
2403 class Entry {
2404 final MethodSymbol cachedImpl;
2405 final Filter<Symbol> implFilter;
2406 final boolean checkResult;
2407 final int prevMark;
2409 public Entry(MethodSymbol cachedImpl,
2410 Filter<Symbol> scopeFilter,
2411 boolean checkResult,
2412 int prevMark) {
2413 this.cachedImpl = cachedImpl;
2414 this.implFilter = scopeFilter;
2415 this.checkResult = checkResult;
2416 this.prevMark = prevMark;
2417 }
2419 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
2420 return this.implFilter == scopeFilter &&
2421 this.checkResult == checkResult &&
2422 this.prevMark == mark;
2423 }
2424 }
2426 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2427 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2428 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2429 if (cache == null) {
2430 cache = new HashMap<TypeSymbol, Entry>();
2431 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2432 }
2433 Entry e = cache.get(origin);
2434 CompoundScope members = membersClosure(origin.type, true);
2435 if (e == null ||
2436 !e.matches(implFilter, checkResult, members.getMark())) {
2437 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2438 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2439 return impl;
2440 }
2441 else {
2442 return e.cachedImpl;
2443 }
2444 }
2446 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2447 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = supertype(t)) {
2448 while (t.tag == TYPEVAR)
2449 t = t.getUpperBound();
2450 TypeSymbol c = t.tsym;
2451 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2452 e.scope != null;
2453 e = e.next(implFilter)) {
2454 if (e.sym != null &&
2455 e.sym.overrides(ms, origin, Types.this, checkResult))
2456 return (MethodSymbol)e.sym;
2457 }
2458 }
2459 return null;
2460 }
2461 }
2463 private ImplementationCache implCache = new ImplementationCache();
2465 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2466 return implCache.get(ms, origin, checkResult, implFilter);
2467 }
2468 // </editor-fold>
2470 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2471 class MembersClosureCache extends SimpleVisitor<CompoundScope, Boolean> {
2473 private WeakHashMap<TypeSymbol, Entry> _map =
2474 new WeakHashMap<TypeSymbol, Entry>();
2476 class Entry {
2477 final boolean skipInterfaces;
2478 final CompoundScope compoundScope;
2480 public Entry(boolean skipInterfaces, CompoundScope compoundScope) {
2481 this.skipInterfaces = skipInterfaces;
2482 this.compoundScope = compoundScope;
2483 }
2485 boolean matches(boolean skipInterfaces) {
2486 return this.skipInterfaces == skipInterfaces;
2487 }
2488 }
2490 List<TypeSymbol> seenTypes = List.nil();
2492 /** members closure visitor methods **/
2494 public CompoundScope visitType(Type t, Boolean skipInterface) {
2495 return null;
2496 }
2498 @Override
2499 public CompoundScope visitClassType(ClassType t, Boolean skipInterface) {
2500 if (seenTypes.contains(t.tsym)) {
2501 //this is possible when an interface is implemented in multiple
2502 //superclasses, or when a classs hierarchy is circular - in such
2503 //cases we don't need to recurse (empty scope is returned)
2504 return new CompoundScope(t.tsym);
2505 }
2506 try {
2507 seenTypes = seenTypes.prepend(t.tsym);
2508 ClassSymbol csym = (ClassSymbol)t.tsym;
2509 Entry e = _map.get(csym);
2510 if (e == null || !e.matches(skipInterface)) {
2511 CompoundScope membersClosure = new CompoundScope(csym);
2512 if (!skipInterface) {
2513 for (Type i : interfaces(t)) {
2514 membersClosure.addSubScope(visit(i, skipInterface));
2515 }
2516 }
2517 membersClosure.addSubScope(visit(supertype(t), skipInterface));
2518 membersClosure.addSubScope(csym.members());
2519 e = new Entry(skipInterface, membersClosure);
2520 _map.put(csym, e);
2521 }
2522 return e.compoundScope;
2523 }
2524 finally {
2525 seenTypes = seenTypes.tail;
2526 }
2527 }
2529 @Override
2530 public CompoundScope visitTypeVar(TypeVar t, Boolean skipInterface) {
2531 return visit(t.getUpperBound(), skipInterface);
2532 }
2533 }
2535 private MembersClosureCache membersCache = new MembersClosureCache();
2537 public CompoundScope membersClosure(Type site, boolean skipInterface) {
2538 return membersCache.visit(site, skipInterface);
2539 }
2540 // </editor-fold>
2543 //where
2544 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
2545 Filter<Symbol> filter = new MethodFilter(ms, site);
2546 List<MethodSymbol> candidates = List.nil();
2547 for (Symbol s : membersClosure(site, false).getElements(filter)) {
2548 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
2549 return List.of((MethodSymbol)s);
2550 } else if (!candidates.contains(s)) {
2551 candidates = candidates.prepend((MethodSymbol)s);
2552 }
2553 }
2554 return prune(candidates, ownerComparator);
2555 }
2557 public List<MethodSymbol> prune(List<MethodSymbol> methods, Comparator<MethodSymbol> cmp) {
2558 ListBuffer<MethodSymbol> methodsMin = ListBuffer.lb();
2559 for (MethodSymbol m1 : methods) {
2560 boolean isMin_m1 = true;
2561 for (MethodSymbol m2 : methods) {
2562 if (m1 == m2) continue;
2563 if (cmp.compare(m2, m1) < 0) {
2564 isMin_m1 = false;
2565 break;
2566 }
2567 }
2568 if (isMin_m1)
2569 methodsMin.append(m1);
2570 }
2571 return methodsMin.toList();
2572 }
2574 Comparator<MethodSymbol> ownerComparator = new Comparator<MethodSymbol>() {
2575 public int compare(MethodSymbol s1, MethodSymbol s2) {
2576 return s1.owner.isSubClass(s2.owner, Types.this) ? -1 : 1;
2577 }
2578 };
2579 // where
2580 private class MethodFilter implements Filter<Symbol> {
2582 Symbol msym;
2583 Type site;
2585 MethodFilter(Symbol msym, Type site) {
2586 this.msym = msym;
2587 this.site = site;
2588 }
2590 public boolean accepts(Symbol s) {
2591 return s.kind == Kinds.MTH &&
2592 s.name == msym.name &&
2593 s.isInheritedIn(site.tsym, Types.this) &&
2594 overrideEquivalent(memberType(site, s), memberType(site, msym));
2595 }
2596 };
2597 // </editor-fold>
2599 /**
2600 * Does t have the same arguments as s? It is assumed that both
2601 * types are (possibly polymorphic) method types. Monomorphic
2602 * method types "have the same arguments", if their argument lists
2603 * are equal. Polymorphic method types "have the same arguments",
2604 * if they have the same arguments after renaming all type
2605 * variables of one to corresponding type variables in the other,
2606 * where correspondence is by position in the type parameter list.
2607 */
2608 public boolean hasSameArgs(Type t, Type s) {
2609 return hasSameArgs(t, s, true);
2610 }
2612 public boolean hasSameArgs(Type t, Type s, boolean strict) {
2613 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
2614 }
2616 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
2617 return hasSameArgs.visit(t, s);
2618 }
2619 // where
2620 private class HasSameArgs extends TypeRelation {
2622 boolean strict;
2624 public HasSameArgs(boolean strict) {
2625 this.strict = strict;
2626 }
2628 public Boolean visitType(Type t, Type s) {
2629 throw new AssertionError();
2630 }
2632 @Override
2633 public Boolean visitMethodType(MethodType t, Type s) {
2634 return s.tag == METHOD
2635 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2636 }
2638 @Override
2639 public Boolean visitForAll(ForAll t, Type s) {
2640 if (s.tag != FORALL)
2641 return strict ? false : visitMethodType(t.asMethodType(), s);
2643 ForAll forAll = (ForAll)s;
2644 return hasSameBounds(t, forAll)
2645 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2646 }
2648 @Override
2649 public Boolean visitErrorType(ErrorType t, Type s) {
2650 return false;
2651 }
2652 };
2654 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
2655 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
2657 // </editor-fold>
2659 // <editor-fold defaultstate="collapsed" desc="subst">
2660 public List<Type> subst(List<Type> ts,
2661 List<Type> from,
2662 List<Type> to) {
2663 return new Subst(from, to).subst(ts);
2664 }
2666 /**
2667 * Substitute all occurrences of a type in `from' with the
2668 * corresponding type in `to' in 't'. Match lists `from' and `to'
2669 * from the right: If lists have different length, discard leading
2670 * elements of the longer list.
2671 */
2672 public Type subst(Type t, List<Type> from, List<Type> to) {
2673 return new Subst(from, to).subst(t);
2674 }
2676 private class Subst extends UnaryVisitor<Type> {
2677 List<Type> from;
2678 List<Type> to;
2680 public Subst(List<Type> from, List<Type> to) {
2681 int fromLength = from.length();
2682 int toLength = to.length();
2683 while (fromLength > toLength) {
2684 fromLength--;
2685 from = from.tail;
2686 }
2687 while (fromLength < toLength) {
2688 toLength--;
2689 to = to.tail;
2690 }
2691 this.from = from;
2692 this.to = to;
2693 }
2695 Type subst(Type t) {
2696 if (from.tail == null)
2697 return t;
2698 else
2699 return visit(t);
2700 }
2702 List<Type> subst(List<Type> ts) {
2703 if (from.tail == null)
2704 return ts;
2705 boolean wild = false;
2706 if (ts.nonEmpty() && from.nonEmpty()) {
2707 Type head1 = subst(ts.head);
2708 List<Type> tail1 = subst(ts.tail);
2709 if (head1 != ts.head || tail1 != ts.tail)
2710 return tail1.prepend(head1);
2711 }
2712 return ts;
2713 }
2715 public Type visitType(Type t, Void ignored) {
2716 return t;
2717 }
2719 @Override
2720 public Type visitMethodType(MethodType t, Void ignored) {
2721 List<Type> argtypes = subst(t.argtypes);
2722 Type restype = subst(t.restype);
2723 List<Type> thrown = subst(t.thrown);
2724 if (argtypes == t.argtypes &&
2725 restype == t.restype &&
2726 thrown == t.thrown)
2727 return t;
2728 else
2729 return new MethodType(argtypes, restype, thrown, t.tsym);
2730 }
2732 @Override
2733 public Type visitTypeVar(TypeVar t, Void ignored) {
2734 for (List<Type> from = this.from, to = this.to;
2735 from.nonEmpty();
2736 from = from.tail, to = to.tail) {
2737 if (t == from.head) {
2738 return to.head.withTypeVar(t);
2739 }
2740 }
2741 return t;
2742 }
2744 @Override
2745 public Type visitClassType(ClassType t, Void ignored) {
2746 if (!t.isCompound()) {
2747 List<Type> typarams = t.getTypeArguments();
2748 List<Type> typarams1 = subst(typarams);
2749 Type outer = t.getEnclosingType();
2750 Type outer1 = subst(outer);
2751 if (typarams1 == typarams && outer1 == outer)
2752 return t;
2753 else
2754 return new ClassType(outer1, typarams1, t.tsym);
2755 } else {
2756 Type st = subst(supertype(t));
2757 List<Type> is = upperBounds(subst(interfaces(t)));
2758 if (st == supertype(t) && is == interfaces(t))
2759 return t;
2760 else
2761 return makeCompoundType(is.prepend(st));
2762 }
2763 }
2765 @Override
2766 public Type visitWildcardType(WildcardType t, Void ignored) {
2767 Type bound = t.type;
2768 if (t.kind != BoundKind.UNBOUND)
2769 bound = subst(bound);
2770 if (bound == t.type) {
2771 return t;
2772 } else {
2773 if (t.isExtendsBound() && bound.isExtendsBound())
2774 bound = upperBound(bound);
2775 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2776 }
2777 }
2779 @Override
2780 public Type visitArrayType(ArrayType t, Void ignored) {
2781 Type elemtype = subst(t.elemtype);
2782 if (elemtype == t.elemtype)
2783 return t;
2784 else
2785 return new ArrayType(upperBound(elemtype), t.tsym);
2786 }
2788 @Override
2789 public Type visitForAll(ForAll t, Void ignored) {
2790 if (Type.containsAny(to, t.tvars)) {
2791 //perform alpha-renaming of free-variables in 't'
2792 //if 'to' types contain variables that are free in 't'
2793 List<Type> freevars = newInstances(t.tvars);
2794 t = new ForAll(freevars,
2795 Types.this.subst(t.qtype, t.tvars, freevars));
2796 }
2797 List<Type> tvars1 = substBounds(t.tvars, from, to);
2798 Type qtype1 = subst(t.qtype);
2799 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2800 return t;
2801 } else if (tvars1 == t.tvars) {
2802 return new ForAll(tvars1, qtype1);
2803 } else {
2804 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2805 }
2806 }
2808 @Override
2809 public Type visitErrorType(ErrorType t, Void ignored) {
2810 return t;
2811 }
2812 }
2814 public List<Type> substBounds(List<Type> tvars,
2815 List<Type> from,
2816 List<Type> to) {
2817 if (tvars.isEmpty())
2818 return tvars;
2819 ListBuffer<Type> newBoundsBuf = lb();
2820 boolean changed = false;
2821 // calculate new bounds
2822 for (Type t : tvars) {
2823 TypeVar tv = (TypeVar) t;
2824 Type bound = subst(tv.bound, from, to);
2825 if (bound != tv.bound)
2826 changed = true;
2827 newBoundsBuf.append(bound);
2828 }
2829 if (!changed)
2830 return tvars;
2831 ListBuffer<Type> newTvars = lb();
2832 // create new type variables without bounds
2833 for (Type t : tvars) {
2834 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2835 }
2836 // the new bounds should use the new type variables in place
2837 // of the old
2838 List<Type> newBounds = newBoundsBuf.toList();
2839 from = tvars;
2840 to = newTvars.toList();
2841 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2842 newBounds.head = subst(newBounds.head, from, to);
2843 }
2844 newBounds = newBoundsBuf.toList();
2845 // set the bounds of new type variables to the new bounds
2846 for (Type t : newTvars.toList()) {
2847 TypeVar tv = (TypeVar) t;
2848 tv.bound = newBounds.head;
2849 newBounds = newBounds.tail;
2850 }
2851 return newTvars.toList();
2852 }
2854 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2855 Type bound1 = subst(t.bound, from, to);
2856 if (bound1 == t.bound)
2857 return t;
2858 else {
2859 // create new type variable without bounds
2860 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2861 // the new bound should use the new type variable in place
2862 // of the old
2863 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2864 return tv;
2865 }
2866 }
2867 // </editor-fold>
2869 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2870 /**
2871 * Does t have the same bounds for quantified variables as s?
2872 */
2873 boolean hasSameBounds(ForAll t, ForAll s) {
2874 List<Type> l1 = t.tvars;
2875 List<Type> l2 = s.tvars;
2876 while (l1.nonEmpty() && l2.nonEmpty() &&
2877 isSameType(l1.head.getUpperBound(),
2878 subst(l2.head.getUpperBound(),
2879 s.tvars,
2880 t.tvars))) {
2881 l1 = l1.tail;
2882 l2 = l2.tail;
2883 }
2884 return l1.isEmpty() && l2.isEmpty();
2885 }
2886 // </editor-fold>
2888 // <editor-fold defaultstate="collapsed" desc="newInstances">
2889 /** Create new vector of type variables from list of variables
2890 * changing all recursive bounds from old to new list.
2891 */
2892 public List<Type> newInstances(List<Type> tvars) {
2893 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2894 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2895 TypeVar tv = (TypeVar) l.head;
2896 tv.bound = subst(tv.bound, tvars, tvars1);
2897 }
2898 return tvars1;
2899 }
2900 private static final Mapping newInstanceFun = new Mapping("newInstanceFun") {
2901 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2902 };
2903 // </editor-fold>
2905 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
2906 return original.accept(methodWithParameters, newParams);
2907 }
2908 // where
2909 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
2910 public Type visitType(Type t, List<Type> newParams) {
2911 throw new IllegalArgumentException("Not a method type: " + t);
2912 }
2913 public Type visitMethodType(MethodType t, List<Type> newParams) {
2914 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
2915 }
2916 public Type visitForAll(ForAll t, List<Type> newParams) {
2917 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
2918 }
2919 };
2921 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
2922 return original.accept(methodWithThrown, newThrown);
2923 }
2924 // where
2925 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
2926 public Type visitType(Type t, List<Type> newThrown) {
2927 throw new IllegalArgumentException("Not a method type: " + t);
2928 }
2929 public Type visitMethodType(MethodType t, List<Type> newThrown) {
2930 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
2931 }
2932 public Type visitForAll(ForAll t, List<Type> newThrown) {
2933 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
2934 }
2935 };
2937 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
2938 return original.accept(methodWithReturn, newReturn);
2939 }
2940 // where
2941 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
2942 public Type visitType(Type t, Type newReturn) {
2943 throw new IllegalArgumentException("Not a method type: " + t);
2944 }
2945 public Type visitMethodType(MethodType t, Type newReturn) {
2946 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym);
2947 }
2948 public Type visitForAll(ForAll t, Type newReturn) {
2949 return new ForAll(t.tvars, t.qtype.accept(this, newReturn));
2950 }
2951 };
2953 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2954 public Type createErrorType(Type originalType) {
2955 return new ErrorType(originalType, syms.errSymbol);
2956 }
2958 public Type createErrorType(ClassSymbol c, Type originalType) {
2959 return new ErrorType(c, originalType);
2960 }
2962 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
2963 return new ErrorType(name, container, originalType);
2964 }
2965 // </editor-fold>
2967 // <editor-fold defaultstate="collapsed" desc="rank">
2968 /**
2969 * The rank of a class is the length of the longest path between
2970 * the class and java.lang.Object in the class inheritance
2971 * graph. Undefined for all but reference types.
2972 */
2973 public int rank(Type t) {
2974 t = t.unannotatedType();
2975 switch(t.tag) {
2976 case CLASS: {
2977 ClassType cls = (ClassType)t;
2978 if (cls.rank_field < 0) {
2979 Name fullname = cls.tsym.getQualifiedName();
2980 if (fullname == names.java_lang_Object)
2981 cls.rank_field = 0;
2982 else {
2983 int r = rank(supertype(cls));
2984 for (List<Type> l = interfaces(cls);
2985 l.nonEmpty();
2986 l = l.tail) {
2987 if (rank(l.head) > r)
2988 r = rank(l.head);
2989 }
2990 cls.rank_field = r + 1;
2991 }
2992 }
2993 return cls.rank_field;
2994 }
2995 case TYPEVAR: {
2996 TypeVar tvar = (TypeVar)t;
2997 if (tvar.rank_field < 0) {
2998 int r = rank(supertype(tvar));
2999 for (List<Type> l = interfaces(tvar);
3000 l.nonEmpty();
3001 l = l.tail) {
3002 if (rank(l.head) > r) r = rank(l.head);
3003 }
3004 tvar.rank_field = r + 1;
3005 }
3006 return tvar.rank_field;
3007 }
3008 case ERROR:
3009 return 0;
3010 default:
3011 throw new AssertionError();
3012 }
3013 }
3014 // </editor-fold>
3016 /**
3017 * Helper method for generating a string representation of a given type
3018 * accordingly to a given locale
3019 */
3020 public String toString(Type t, Locale locale) {
3021 return Printer.createStandardPrinter(messages).visit(t, locale);
3022 }
3024 /**
3025 * Helper method for generating a string representation of a given type
3026 * accordingly to a given locale
3027 */
3028 public String toString(Symbol t, Locale locale) {
3029 return Printer.createStandardPrinter(messages).visit(t, locale);
3030 }
3032 // <editor-fold defaultstate="collapsed" desc="toString">
3033 /**
3034 * This toString is slightly more descriptive than the one on Type.
3035 *
3036 * @deprecated Types.toString(Type t, Locale l) provides better support
3037 * for localization
3038 */
3039 @Deprecated
3040 public String toString(Type t) {
3041 if (t.tag == FORALL) {
3042 ForAll forAll = (ForAll)t;
3043 return typaramsString(forAll.tvars) + forAll.qtype;
3044 }
3045 return "" + t;
3046 }
3047 // where
3048 private String typaramsString(List<Type> tvars) {
3049 StringBuilder s = new StringBuilder();
3050 s.append('<');
3051 boolean first = true;
3052 for (Type t : tvars) {
3053 if (!first) s.append(", ");
3054 first = false;
3055 appendTyparamString(((TypeVar)t), s);
3056 }
3057 s.append('>');
3058 return s.toString();
3059 }
3060 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3061 buf.append(t);
3062 if (t.bound == null ||
3063 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
3064 return;
3065 buf.append(" extends "); // Java syntax; no need for i18n
3066 Type bound = t.bound;
3067 if (!bound.isCompound()) {
3068 buf.append(bound);
3069 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3070 buf.append(supertype(t));
3071 for (Type intf : interfaces(t)) {
3072 buf.append('&');
3073 buf.append(intf);
3074 }
3075 } else {
3076 // No superclass was given in bounds.
3077 // In this case, supertype is Object, erasure is first interface.
3078 boolean first = true;
3079 for (Type intf : interfaces(t)) {
3080 if (!first) buf.append('&');
3081 first = false;
3082 buf.append(intf);
3083 }
3084 }
3085 }
3086 // </editor-fold>
3088 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3089 /**
3090 * A cache for closures.
3091 *
3092 * <p>A closure is a list of all the supertypes and interfaces of
3093 * a class or interface type, ordered by ClassSymbol.precedes
3094 * (that is, subclasses come first, arbitrary but fixed
3095 * otherwise).
3096 */
3097 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
3099 /**
3100 * Returns the closure of a class or interface type.
3101 */
3102 public List<Type> closure(Type t) {
3103 List<Type> cl = closureCache.get(t);
3104 if (cl == null) {
3105 Type st = supertype(t);
3106 if (!t.isCompound()) {
3107 if (st.tag == CLASS) {
3108 cl = insert(closure(st), t);
3109 } else if (st.tag == TYPEVAR) {
3110 cl = closure(st).prepend(t);
3111 } else {
3112 cl = List.of(t);
3113 }
3114 } else {
3115 cl = closure(supertype(t));
3116 }
3117 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3118 cl = union(cl, closure(l.head));
3119 closureCache.put(t, cl);
3120 }
3121 return cl;
3122 }
3124 /**
3125 * Insert a type in a closure
3126 */
3127 public List<Type> insert(List<Type> cl, Type t) {
3128 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
3129 return cl.prepend(t);
3130 } else if (cl.head.tsym.precedes(t.tsym, this)) {
3131 return insert(cl.tail, t).prepend(cl.head);
3132 } else {
3133 return cl;
3134 }
3135 }
3137 /**
3138 * Form the union of two closures
3139 */
3140 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3141 if (cl1.isEmpty()) {
3142 return cl2;
3143 } else if (cl2.isEmpty()) {
3144 return cl1;
3145 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
3146 return union(cl1.tail, cl2).prepend(cl1.head);
3147 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3148 return union(cl1, cl2.tail).prepend(cl2.head);
3149 } else {
3150 return union(cl1.tail, cl2.tail).prepend(cl1.head);
3151 }
3152 }
3154 /**
3155 * Intersect two closures
3156 */
3157 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3158 if (cl1 == cl2)
3159 return cl1;
3160 if (cl1.isEmpty() || cl2.isEmpty())
3161 return List.nil();
3162 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3163 return intersect(cl1.tail, cl2);
3164 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3165 return intersect(cl1, cl2.tail);
3166 if (isSameType(cl1.head, cl2.head))
3167 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3168 if (cl1.head.tsym == cl2.head.tsym &&
3169 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
3170 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3171 Type merge = merge(cl1.head,cl2.head);
3172 return intersect(cl1.tail, cl2.tail).prepend(merge);
3173 }
3174 if (cl1.head.isRaw() || cl2.head.isRaw())
3175 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3176 }
3177 return intersect(cl1.tail, cl2.tail);
3178 }
3179 // where
3180 class TypePair {
3181 final Type t1;
3182 final Type t2;
3183 TypePair(Type t1, Type t2) {
3184 this.t1 = t1;
3185 this.t2 = t2;
3186 }
3187 @Override
3188 public int hashCode() {
3189 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3190 }
3191 @Override
3192 public boolean equals(Object obj) {
3193 if (!(obj instanceof TypePair))
3194 return false;
3195 TypePair typePair = (TypePair)obj;
3196 return isSameType(t1, typePair.t1)
3197 && isSameType(t2, typePair.t2);
3198 }
3199 }
3200 Set<TypePair> mergeCache = new HashSet<TypePair>();
3201 private Type merge(Type c1, Type c2) {
3202 ClassType class1 = (ClassType) c1;
3203 List<Type> act1 = class1.getTypeArguments();
3204 ClassType class2 = (ClassType) c2;
3205 List<Type> act2 = class2.getTypeArguments();
3206 ListBuffer<Type> merged = new ListBuffer<Type>();
3207 List<Type> typarams = class1.tsym.type.getTypeArguments();
3209 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3210 if (containsType(act1.head, act2.head)) {
3211 merged.append(act1.head);
3212 } else if (containsType(act2.head, act1.head)) {
3213 merged.append(act2.head);
3214 } else {
3215 TypePair pair = new TypePair(c1, c2);
3216 Type m;
3217 if (mergeCache.add(pair)) {
3218 m = new WildcardType(lub(upperBound(act1.head),
3219 upperBound(act2.head)),
3220 BoundKind.EXTENDS,
3221 syms.boundClass);
3222 mergeCache.remove(pair);
3223 } else {
3224 m = new WildcardType(syms.objectType,
3225 BoundKind.UNBOUND,
3226 syms.boundClass);
3227 }
3228 merged.append(m.withTypeVar(typarams.head));
3229 }
3230 act1 = act1.tail;
3231 act2 = act2.tail;
3232 typarams = typarams.tail;
3233 }
3234 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3235 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
3236 }
3238 /**
3239 * Return the minimum type of a closure, a compound type if no
3240 * unique minimum exists.
3241 */
3242 private Type compoundMin(List<Type> cl) {
3243 if (cl.isEmpty()) return syms.objectType;
3244 List<Type> compound = closureMin(cl);
3245 if (compound.isEmpty())
3246 return null;
3247 else if (compound.tail.isEmpty())
3248 return compound.head;
3249 else
3250 return makeCompoundType(compound);
3251 }
3253 /**
3254 * Return the minimum types of a closure, suitable for computing
3255 * compoundMin or glb.
3256 */
3257 private List<Type> closureMin(List<Type> cl) {
3258 ListBuffer<Type> classes = lb();
3259 ListBuffer<Type> interfaces = lb();
3260 while (!cl.isEmpty()) {
3261 Type current = cl.head;
3262 if (current.isInterface())
3263 interfaces.append(current);
3264 else
3265 classes.append(current);
3266 ListBuffer<Type> candidates = lb();
3267 for (Type t : cl.tail) {
3268 if (!isSubtypeNoCapture(current, t))
3269 candidates.append(t);
3270 }
3271 cl = candidates.toList();
3272 }
3273 return classes.appendList(interfaces).toList();
3274 }
3276 /**
3277 * Return the least upper bound of pair of types. if the lub does
3278 * not exist return null.
3279 */
3280 public Type lub(Type t1, Type t2) {
3281 return lub(List.of(t1, t2));
3282 }
3284 /**
3285 * Return the least upper bound (lub) of set of types. If the lub
3286 * does not exist return the type of null (bottom).
3287 */
3288 public Type lub(List<Type> ts) {
3289 final int ARRAY_BOUND = 1;
3290 final int CLASS_BOUND = 2;
3291 int boundkind = 0;
3292 for (Type t : ts) {
3293 switch (t.tag) {
3294 case CLASS:
3295 boundkind |= CLASS_BOUND;
3296 break;
3297 case ARRAY:
3298 boundkind |= ARRAY_BOUND;
3299 break;
3300 case TYPEVAR:
3301 do {
3302 t = t.getUpperBound();
3303 } while (t.tag == TYPEVAR);
3304 if (t.tag == ARRAY) {
3305 boundkind |= ARRAY_BOUND;
3306 } else {
3307 boundkind |= CLASS_BOUND;
3308 }
3309 break;
3310 default:
3311 if (t.isPrimitive())
3312 return syms.errType;
3313 }
3314 }
3315 switch (boundkind) {
3316 case 0:
3317 return syms.botType;
3319 case ARRAY_BOUND:
3320 // calculate lub(A[], B[])
3321 List<Type> elements = Type.map(ts, elemTypeFun);
3322 for (Type t : elements) {
3323 if (t.isPrimitive()) {
3324 // if a primitive type is found, then return
3325 // arraySuperType unless all the types are the
3326 // same
3327 Type first = ts.head;
3328 for (Type s : ts.tail) {
3329 if (!isSameType(first, s)) {
3330 // lub(int[], B[]) is Cloneable & Serializable
3331 return arraySuperType();
3332 }
3333 }
3334 // all the array types are the same, return one
3335 // lub(int[], int[]) is int[]
3336 return first;
3337 }
3338 }
3339 // lub(A[], B[]) is lub(A, B)[]
3340 return new ArrayType(lub(elements), syms.arrayClass);
3342 case CLASS_BOUND:
3343 // calculate lub(A, B)
3344 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
3345 ts = ts.tail;
3346 Assert.check(!ts.isEmpty());
3347 //step 1 - compute erased candidate set (EC)
3348 List<Type> cl = erasedSupertypes(ts.head);
3349 for (Type t : ts.tail) {
3350 if (t.tag == CLASS || t.tag == TYPEVAR)
3351 cl = intersect(cl, erasedSupertypes(t));
3352 }
3353 //step 2 - compute minimal erased candidate set (MEC)
3354 List<Type> mec = closureMin(cl);
3355 //step 3 - for each element G in MEC, compute lci(Inv(G))
3356 List<Type> candidates = List.nil();
3357 for (Type erasedSupertype : mec) {
3358 List<Type> lci = List.of(asSuper(ts.head, erasedSupertype.tsym));
3359 for (Type t : ts) {
3360 lci = intersect(lci, List.of(asSuper(t, erasedSupertype.tsym)));
3361 }
3362 candidates = candidates.appendList(lci);
3363 }
3364 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
3365 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
3366 return compoundMin(candidates);
3368 default:
3369 // calculate lub(A, B[])
3370 List<Type> classes = List.of(arraySuperType());
3371 for (Type t : ts) {
3372 if (t.tag != ARRAY) // Filter out any arrays
3373 classes = classes.prepend(t);
3374 }
3375 // lub(A, B[]) is lub(A, arraySuperType)
3376 return lub(classes);
3377 }
3378 }
3379 // where
3380 List<Type> erasedSupertypes(Type t) {
3381 ListBuffer<Type> buf = lb();
3382 for (Type sup : closure(t)) {
3383 if (sup.tag == TYPEVAR) {
3384 buf.append(sup);
3385 } else {
3386 buf.append(erasure(sup));
3387 }
3388 }
3389 return buf.toList();
3390 }
3392 private Type arraySuperType = null;
3393 private Type arraySuperType() {
3394 // initialized lazily to avoid problems during compiler startup
3395 if (arraySuperType == null) {
3396 synchronized (this) {
3397 if (arraySuperType == null) {
3398 // JLS 10.8: all arrays implement Cloneable and Serializable.
3399 arraySuperType = makeCompoundType(List.of(syms.serializableType,
3400 syms.cloneableType), true);
3401 }
3402 }
3403 }
3404 return arraySuperType;
3405 }
3406 // </editor-fold>
3408 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
3409 public Type glb(List<Type> ts) {
3410 Type t1 = ts.head;
3411 for (Type t2 : ts.tail) {
3412 if (t1.isErroneous())
3413 return t1;
3414 t1 = glb(t1, t2);
3415 }
3416 return t1;
3417 }
3418 //where
3419 public Type glb(Type t, Type s) {
3420 if (s == null)
3421 return t;
3422 else if (t.isPrimitive() || s.isPrimitive())
3423 return syms.errType;
3424 else if (isSubtypeNoCapture(t, s))
3425 return t;
3426 else if (isSubtypeNoCapture(s, t))
3427 return s;
3429 List<Type> closure = union(closure(t), closure(s));
3430 List<Type> bounds = closureMin(closure);
3432 if (bounds.isEmpty()) { // length == 0
3433 return syms.objectType;
3434 } else if (bounds.tail.isEmpty()) { // length == 1
3435 return bounds.head;
3436 } else { // length > 1
3437 int classCount = 0;
3438 for (Type bound : bounds)
3439 if (!bound.isInterface())
3440 classCount++;
3441 if (classCount > 1)
3442 return createErrorType(t);
3443 }
3444 return makeCompoundType(bounds);
3445 }
3446 // </editor-fold>
3448 // <editor-fold defaultstate="collapsed" desc="hashCode">
3449 /**
3450 * Compute a hash code on a type.
3451 */
3452 public int hashCode(Type t) {
3453 return hashCode.visit(t);
3454 }
3455 // where
3456 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
3458 public Integer visitType(Type t, Void ignored) {
3459 return t.tag.ordinal();
3460 }
3462 @Override
3463 public Integer visitClassType(ClassType t, Void ignored) {
3464 int result = visit(t.getEnclosingType());
3465 result *= 127;
3466 result += t.tsym.flatName().hashCode();
3467 for (Type s : t.getTypeArguments()) {
3468 result *= 127;
3469 result += visit(s);
3470 }
3471 return result;
3472 }
3474 @Override
3475 public Integer visitMethodType(MethodType t, Void ignored) {
3476 int h = METHOD.ordinal();
3477 for (List<Type> thisargs = t.argtypes;
3478 thisargs.tail != null;
3479 thisargs = thisargs.tail)
3480 h = (h << 5) + visit(thisargs.head);
3481 return (h << 5) + visit(t.restype);
3482 }
3484 @Override
3485 public Integer visitWildcardType(WildcardType t, Void ignored) {
3486 int result = t.kind.hashCode();
3487 if (t.type != null) {
3488 result *= 127;
3489 result += visit(t.type);
3490 }
3491 return result;
3492 }
3494 @Override
3495 public Integer visitArrayType(ArrayType t, Void ignored) {
3496 return visit(t.elemtype) + 12;
3497 }
3499 @Override
3500 public Integer visitTypeVar(TypeVar t, Void ignored) {
3501 return System.identityHashCode(t.tsym);
3502 }
3504 @Override
3505 public Integer visitUndetVar(UndetVar t, Void ignored) {
3506 return System.identityHashCode(t);
3507 }
3509 @Override
3510 public Integer visitErrorType(ErrorType t, Void ignored) {
3511 return 0;
3512 }
3513 };
3514 // </editor-fold>
3516 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
3517 /**
3518 * Does t have a result that is a subtype of the result type of s,
3519 * suitable for covariant returns? It is assumed that both types
3520 * are (possibly polymorphic) method types. Monomorphic method
3521 * types are handled in the obvious way. Polymorphic method types
3522 * require renaming all type variables of one to corresponding
3523 * type variables in the other, where correspondence is by
3524 * position in the type parameter list. */
3525 public boolean resultSubtype(Type t, Type s, Warner warner) {
3526 List<Type> tvars = t.getTypeArguments();
3527 List<Type> svars = s.getTypeArguments();
3528 Type tres = t.getReturnType();
3529 Type sres = subst(s.getReturnType(), svars, tvars);
3530 return covariantReturnType(tres, sres, warner);
3531 }
3533 /**
3534 * Return-Type-Substitutable.
3535 * @jls section 8.4.5
3536 */
3537 public boolean returnTypeSubstitutable(Type r1, Type r2) {
3538 if (hasSameArgs(r1, r2))
3539 return resultSubtype(r1, r2, noWarnings);
3540 else
3541 return covariantReturnType(r1.getReturnType(),
3542 erasure(r2.getReturnType()),
3543 noWarnings);
3544 }
3546 public boolean returnTypeSubstitutable(Type r1,
3547 Type r2, Type r2res,
3548 Warner warner) {
3549 if (isSameType(r1.getReturnType(), r2res))
3550 return true;
3551 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
3552 return false;
3554 if (hasSameArgs(r1, r2))
3555 return covariantReturnType(r1.getReturnType(), r2res, warner);
3556 if (!allowCovariantReturns)
3557 return false;
3558 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
3559 return true;
3560 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
3561 return false;
3562 warner.warn(LintCategory.UNCHECKED);
3563 return true;
3564 }
3566 /**
3567 * Is t an appropriate return type in an overrider for a
3568 * method that returns s?
3569 */
3570 public boolean covariantReturnType(Type t, Type s, Warner warner) {
3571 return
3572 isSameType(t, s) ||
3573 allowCovariantReturns &&
3574 !t.isPrimitive() &&
3575 !s.isPrimitive() &&
3576 isAssignable(t, s, warner);
3577 }
3578 // </editor-fold>
3580 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
3581 /**
3582 * Return the class that boxes the given primitive.
3583 */
3584 public ClassSymbol boxedClass(Type t) {
3585 return reader.enterClass(syms.boxedName[t.tag.ordinal()]);
3586 }
3588 /**
3589 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
3590 */
3591 public Type boxedTypeOrType(Type t) {
3592 return t.isPrimitive() ?
3593 boxedClass(t).type :
3594 t;
3595 }
3597 /**
3598 * Return the primitive type corresponding to a boxed type.
3599 */
3600 public Type unboxedType(Type t) {
3601 if (allowBoxing) {
3602 for (int i=0; i<syms.boxedName.length; i++) {
3603 Name box = syms.boxedName[i];
3604 if (box != null &&
3605 asSuper(t, reader.enterClass(box)) != null)
3606 return syms.typeOfTag[i];
3607 }
3608 }
3609 return Type.noType;
3610 }
3612 /**
3613 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
3614 */
3615 public Type unboxedTypeOrType(Type t) {
3616 Type unboxedType = unboxedType(t);
3617 return unboxedType.tag == NONE ? t : unboxedType;
3618 }
3619 // </editor-fold>
3621 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3622 /*
3623 * JLS 5.1.10 Capture Conversion:
3624 *
3625 * Let G name a generic type declaration with n formal type
3626 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3627 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3628 * where, for 1 <= i <= n:
3629 *
3630 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3631 * Si is a fresh type variable whose upper bound is
3632 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3633 * type.
3634 *
3635 * + If Ti is a wildcard type argument of the form ? extends Bi,
3636 * then Si is a fresh type variable whose upper bound is
3637 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3638 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3639 * a compile-time error if for any two classes (not interfaces)
3640 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3641 *
3642 * + If Ti is a wildcard type argument of the form ? super Bi,
3643 * then Si is a fresh type variable whose upper bound is
3644 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3645 *
3646 * + Otherwise, Si = Ti.
3647 *
3648 * Capture conversion on any type other than a parameterized type
3649 * (4.5) acts as an identity conversion (5.1.1). Capture
3650 * conversions never require a special action at run time and
3651 * therefore never throw an exception at run time.
3652 *
3653 * Capture conversion is not applied recursively.
3654 */
3655 /**
3656 * Capture conversion as specified by the JLS.
3657 */
3659 public List<Type> capture(List<Type> ts) {
3660 List<Type> buf = List.nil();
3661 for (Type t : ts) {
3662 buf = buf.prepend(capture(t));
3663 }
3664 return buf.reverse();
3665 }
3666 public Type capture(Type t) {
3667 if (t.tag != CLASS)
3668 return t;
3669 if (t.getEnclosingType() != Type.noType) {
3670 Type capturedEncl = capture(t.getEnclosingType());
3671 if (capturedEncl != t.getEnclosingType()) {
3672 Type type1 = memberType(capturedEncl, t.tsym);
3673 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3674 }
3675 }
3676 t = t.unannotatedType();
3677 ClassType cls = (ClassType)t;
3678 if (cls.isRaw() || !cls.isParameterized())
3679 return cls;
3681 ClassType G = (ClassType)cls.asElement().asType();
3682 List<Type> A = G.getTypeArguments();
3683 List<Type> T = cls.getTypeArguments();
3684 List<Type> S = freshTypeVariables(T);
3686 List<Type> currentA = A;
3687 List<Type> currentT = T;
3688 List<Type> currentS = S;
3689 boolean captured = false;
3690 while (!currentA.isEmpty() &&
3691 !currentT.isEmpty() &&
3692 !currentS.isEmpty()) {
3693 if (currentS.head != currentT.head) {
3694 captured = true;
3695 WildcardType Ti = (WildcardType)currentT.head;
3696 Type Ui = currentA.head.getUpperBound();
3697 CapturedType Si = (CapturedType)currentS.head;
3698 if (Ui == null)
3699 Ui = syms.objectType;
3700 switch (Ti.kind) {
3701 case UNBOUND:
3702 Si.bound = subst(Ui, A, S);
3703 Si.lower = syms.botType;
3704 break;
3705 case EXTENDS:
3706 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3707 Si.lower = syms.botType;
3708 break;
3709 case SUPER:
3710 Si.bound = subst(Ui, A, S);
3711 Si.lower = Ti.getSuperBound();
3712 break;
3713 }
3714 if (Si.bound == Si.lower)
3715 currentS.head = Si.bound;
3716 }
3717 currentA = currentA.tail;
3718 currentT = currentT.tail;
3719 currentS = currentS.tail;
3720 }
3721 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3722 return erasure(t); // some "rare" type involved
3724 if (captured)
3725 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3726 else
3727 return t;
3728 }
3729 // where
3730 public List<Type> freshTypeVariables(List<Type> types) {
3731 ListBuffer<Type> result = lb();
3732 for (Type t : types) {
3733 if (t.tag == WILDCARD) {
3734 Type bound = ((WildcardType)t).getExtendsBound();
3735 if (bound == null)
3736 bound = syms.objectType;
3737 result.append(new CapturedType(capturedName,
3738 syms.noSymbol,
3739 bound,
3740 syms.botType,
3741 (WildcardType)t));
3742 } else {
3743 result.append(t);
3744 }
3745 }
3746 return result.toList();
3747 }
3748 // </editor-fold>
3750 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3751 private List<Type> upperBounds(List<Type> ss) {
3752 if (ss.isEmpty()) return ss;
3753 Type head = upperBound(ss.head);
3754 List<Type> tail = upperBounds(ss.tail);
3755 if (head != ss.head || tail != ss.tail)
3756 return tail.prepend(head);
3757 else
3758 return ss;
3759 }
3761 private boolean sideCast(Type from, Type to, Warner warn) {
3762 // We are casting from type $from$ to type $to$, which are
3763 // non-final unrelated types. This method
3764 // tries to reject a cast by transferring type parameters
3765 // from $to$ to $from$ by common superinterfaces.
3766 boolean reverse = false;
3767 Type target = to;
3768 if ((to.tsym.flags() & INTERFACE) == 0) {
3769 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3770 reverse = true;
3771 to = from;
3772 from = target;
3773 }
3774 List<Type> commonSupers = superClosure(to, erasure(from));
3775 boolean giveWarning = commonSupers.isEmpty();
3776 // The arguments to the supers could be unified here to
3777 // get a more accurate analysis
3778 while (commonSupers.nonEmpty()) {
3779 Type t1 = asSuper(from, commonSupers.head.tsym);
3780 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3781 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3782 return false;
3783 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3784 commonSupers = commonSupers.tail;
3785 }
3786 if (giveWarning && !isReifiable(reverse ? from : to))
3787 warn.warn(LintCategory.UNCHECKED);
3788 if (!allowCovariantReturns)
3789 // reject if there is a common method signature with
3790 // incompatible return types.
3791 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3792 return true;
3793 }
3795 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3796 // We are casting from type $from$ to type $to$, which are
3797 // unrelated types one of which is final and the other of
3798 // which is an interface. This method
3799 // tries to reject a cast by transferring type parameters
3800 // from the final class to the interface.
3801 boolean reverse = false;
3802 Type target = to;
3803 if ((to.tsym.flags() & INTERFACE) == 0) {
3804 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3805 reverse = true;
3806 to = from;
3807 from = target;
3808 }
3809 Assert.check((from.tsym.flags() & FINAL) != 0);
3810 Type t1 = asSuper(from, to.tsym);
3811 if (t1 == null) return false;
3812 Type t2 = to;
3813 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3814 return false;
3815 if (!allowCovariantReturns)
3816 // reject if there is a common method signature with
3817 // incompatible return types.
3818 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3819 if (!isReifiable(target) &&
3820 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3821 warn.warn(LintCategory.UNCHECKED);
3822 return true;
3823 }
3825 private boolean giveWarning(Type from, Type to) {
3826 Type subFrom = asSub(from, to.tsym);
3827 return to.isParameterized() &&
3828 (!(isUnbounded(to) ||
3829 isSubtype(from, to) ||
3830 ((subFrom != null) && containsType(to.allparams(), subFrom.allparams()))));
3831 }
3833 private List<Type> superClosure(Type t, Type s) {
3834 List<Type> cl = List.nil();
3835 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3836 if (isSubtype(s, erasure(l.head))) {
3837 cl = insert(cl, l.head);
3838 } else {
3839 cl = union(cl, superClosure(l.head, s));
3840 }
3841 }
3842 return cl;
3843 }
3845 private boolean containsTypeEquivalent(Type t, Type s) {
3846 return
3847 isSameType(t, s) || // shortcut
3848 containsType(t, s) && containsType(s, t);
3849 }
3851 // <editor-fold defaultstate="collapsed" desc="adapt">
3852 /**
3853 * Adapt a type by computing a substitution which maps a source
3854 * type to a target type.
3855 *
3856 * @param source the source type
3857 * @param target the target type
3858 * @param from the type variables of the computed substitution
3859 * @param to the types of the computed substitution.
3860 */
3861 public void adapt(Type source,
3862 Type target,
3863 ListBuffer<Type> from,
3864 ListBuffer<Type> to) throws AdaptFailure {
3865 new Adapter(from, to).adapt(source, target);
3866 }
3868 class Adapter extends SimpleVisitor<Void, Type> {
3870 ListBuffer<Type> from;
3871 ListBuffer<Type> to;
3872 Map<Symbol,Type> mapping;
3874 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3875 this.from = from;
3876 this.to = to;
3877 mapping = new HashMap<Symbol,Type>();
3878 }
3880 public void adapt(Type source, Type target) throws AdaptFailure {
3881 visit(source, target);
3882 List<Type> fromList = from.toList();
3883 List<Type> toList = to.toList();
3884 while (!fromList.isEmpty()) {
3885 Type val = mapping.get(fromList.head.tsym);
3886 if (toList.head != val)
3887 toList.head = val;
3888 fromList = fromList.tail;
3889 toList = toList.tail;
3890 }
3891 }
3893 @Override
3894 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3895 if (target.tag == CLASS)
3896 adaptRecursive(source.allparams(), target.allparams());
3897 return null;
3898 }
3900 @Override
3901 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3902 if (target.tag == ARRAY)
3903 adaptRecursive(elemtype(source), elemtype(target));
3904 return null;
3905 }
3907 @Override
3908 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3909 if (source.isExtendsBound())
3910 adaptRecursive(upperBound(source), upperBound(target));
3911 else if (source.isSuperBound())
3912 adaptRecursive(lowerBound(source), lowerBound(target));
3913 return null;
3914 }
3916 @Override
3917 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3918 // Check to see if there is
3919 // already a mapping for $source$, in which case
3920 // the old mapping will be merged with the new
3921 Type val = mapping.get(source.tsym);
3922 if (val != null) {
3923 if (val.isSuperBound() && target.isSuperBound()) {
3924 val = isSubtype(lowerBound(val), lowerBound(target))
3925 ? target : val;
3926 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3927 val = isSubtype(upperBound(val), upperBound(target))
3928 ? val : target;
3929 } else if (!isSameType(val, target)) {
3930 throw new AdaptFailure();
3931 }
3932 } else {
3933 val = target;
3934 from.append(source);
3935 to.append(target);
3936 }
3937 mapping.put(source.tsym, val);
3938 return null;
3939 }
3941 @Override
3942 public Void visitType(Type source, Type target) {
3943 return null;
3944 }
3946 private Set<TypePair> cache = new HashSet<TypePair>();
3948 private void adaptRecursive(Type source, Type target) {
3949 TypePair pair = new TypePair(source, target);
3950 if (cache.add(pair)) {
3951 try {
3952 visit(source, target);
3953 } finally {
3954 cache.remove(pair);
3955 }
3956 }
3957 }
3959 private void adaptRecursive(List<Type> source, List<Type> target) {
3960 if (source.length() == target.length()) {
3961 while (source.nonEmpty()) {
3962 adaptRecursive(source.head, target.head);
3963 source = source.tail;
3964 target = target.tail;
3965 }
3966 }
3967 }
3968 }
3970 public static class AdaptFailure extends RuntimeException {
3971 static final long serialVersionUID = -7490231548272701566L;
3972 }
3974 private void adaptSelf(Type t,
3975 ListBuffer<Type> from,
3976 ListBuffer<Type> to) {
3977 try {
3978 //if (t.tsym.type != t)
3979 adapt(t.tsym.type, t, from, to);
3980 } catch (AdaptFailure ex) {
3981 // Adapt should never fail calculating a mapping from
3982 // t.tsym.type to t as there can be no merge problem.
3983 throw new AssertionError(ex);
3984 }
3985 }
3986 // </editor-fold>
3988 /**
3989 * Rewrite all type variables (universal quantifiers) in the given
3990 * type to wildcards (existential quantifiers). This is used to
3991 * determine if a cast is allowed. For example, if high is true
3992 * and {@code T <: Number}, then {@code List<T>} is rewritten to
3993 * {@code List<? extends Number>}. Since {@code List<Integer> <:
3994 * List<? extends Number>} a {@code List<T>} can be cast to {@code
3995 * List<Integer>} with a warning.
3996 * @param t a type
3997 * @param high if true return an upper bound; otherwise a lower
3998 * bound
3999 * @param rewriteTypeVars only rewrite captured wildcards if false;
4000 * otherwise rewrite all type variables
4001 * @return the type rewritten with wildcards (existential
4002 * quantifiers) only
4003 */
4004 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4005 return new Rewriter(high, rewriteTypeVars).visit(t);
4006 }
4008 class Rewriter extends UnaryVisitor<Type> {
4010 boolean high;
4011 boolean rewriteTypeVars;
4013 Rewriter(boolean high, boolean rewriteTypeVars) {
4014 this.high = high;
4015 this.rewriteTypeVars = rewriteTypeVars;
4016 }
4018 @Override
4019 public Type visitClassType(ClassType t, Void s) {
4020 ListBuffer<Type> rewritten = new ListBuffer<Type>();
4021 boolean changed = false;
4022 for (Type arg : t.allparams()) {
4023 Type bound = visit(arg);
4024 if (arg != bound) {
4025 changed = true;
4026 }
4027 rewritten.append(bound);
4028 }
4029 if (changed)
4030 return subst(t.tsym.type,
4031 t.tsym.type.allparams(),
4032 rewritten.toList());
4033 else
4034 return t;
4035 }
4037 public Type visitType(Type t, Void s) {
4038 return high ? upperBound(t) : lowerBound(t);
4039 }
4041 @Override
4042 public Type visitCapturedType(CapturedType t, Void s) {
4043 Type w_bound = t.wildcard.type;
4044 Type bound = w_bound.contains(t) ?
4045 erasure(w_bound) :
4046 visit(w_bound);
4047 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4048 }
4050 @Override
4051 public Type visitTypeVar(TypeVar t, Void s) {
4052 if (rewriteTypeVars) {
4053 Type bound = t.bound.contains(t) ?
4054 erasure(t.bound) :
4055 visit(t.bound);
4056 return rewriteAsWildcardType(bound, t, EXTENDS);
4057 } else {
4058 return t;
4059 }
4060 }
4062 @Override
4063 public Type visitWildcardType(WildcardType t, Void s) {
4064 Type bound2 = visit(t.type);
4065 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4066 }
4068 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4069 switch (bk) {
4070 case EXTENDS: return high ?
4071 makeExtendsWildcard(B(bound), formal) :
4072 makeExtendsWildcard(syms.objectType, formal);
4073 case SUPER: return high ?
4074 makeSuperWildcard(syms.botType, formal) :
4075 makeSuperWildcard(B(bound), formal);
4076 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4077 default:
4078 Assert.error("Invalid bound kind " + bk);
4079 return null;
4080 }
4081 }
4083 Type B(Type t) {
4084 while (t.tag == WILDCARD) {
4085 WildcardType w = (WildcardType)t;
4086 t = high ?
4087 w.getExtendsBound() :
4088 w.getSuperBound();
4089 if (t == null) {
4090 t = high ? syms.objectType : syms.botType;
4091 }
4092 }
4093 return t;
4094 }
4095 }
4098 /**
4099 * Create a wildcard with the given upper (extends) bound; create
4100 * an unbounded wildcard if bound is Object.
4101 *
4102 * @param bound the upper bound
4103 * @param formal the formal type parameter that will be
4104 * substituted by the wildcard
4105 */
4106 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4107 if (bound == syms.objectType) {
4108 return new WildcardType(syms.objectType,
4109 BoundKind.UNBOUND,
4110 syms.boundClass,
4111 formal);
4112 } else {
4113 return new WildcardType(bound,
4114 BoundKind.EXTENDS,
4115 syms.boundClass,
4116 formal);
4117 }
4118 }
4120 /**
4121 * Create a wildcard with the given lower (super) bound; create an
4122 * unbounded wildcard if bound is bottom (type of {@code null}).
4123 *
4124 * @param bound the lower bound
4125 * @param formal the formal type parameter that will be
4126 * substituted by the wildcard
4127 */
4128 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4129 if (bound.tag == BOT) {
4130 return new WildcardType(syms.objectType,
4131 BoundKind.UNBOUND,
4132 syms.boundClass,
4133 formal);
4134 } else {
4135 return new WildcardType(bound,
4136 BoundKind.SUPER,
4137 syms.boundClass,
4138 formal);
4139 }
4140 }
4142 /**
4143 * A wrapper for a type that allows use in sets.
4144 */
4145 public static class UniqueType {
4146 public final Type type;
4147 final Types types;
4149 public UniqueType(Type type, Types types) {
4150 this.type = type;
4151 this.types = types;
4152 }
4154 public int hashCode() {
4155 return types.hashCode(type);
4156 }
4158 public boolean equals(Object obj) {
4159 return (obj instanceof UniqueType) &&
4160 types.isSameType(type, ((UniqueType)obj).type);
4161 }
4163 public String toString() {
4164 return type.toString();
4165 }
4167 }
4168 // </editor-fold>
4170 // <editor-fold defaultstate="collapsed" desc="Visitors">
4171 /**
4172 * A default visitor for types. All visitor methods except
4173 * visitType are implemented by delegating to visitType. Concrete
4174 * subclasses must provide an implementation of visitType and can
4175 * override other methods as needed.
4176 *
4177 * @param <R> the return type of the operation implemented by this
4178 * visitor; use Void if no return type is needed.
4179 * @param <S> the type of the second argument (the first being the
4180 * type itself) of the operation implemented by this visitor; use
4181 * Void if a second argument is not needed.
4182 */
4183 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4184 final public R visit(Type t, S s) { return t.accept(this, s); }
4185 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4186 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4187 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4188 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4189 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4190 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4191 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4192 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4193 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4194 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4195 // Pretend annotations don't exist
4196 public R visitAnnotatedType(AnnotatedType t, S s) { return visit(t.underlyingType, s); }
4197 }
4199 /**
4200 * A default visitor for symbols. All visitor methods except
4201 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4202 * subclasses must provide an implementation of visitSymbol and can
4203 * override other methods as needed.
4204 *
4205 * @param <R> the return type of the operation implemented by this
4206 * visitor; use Void if no return type is needed.
4207 * @param <S> the type of the second argument (the first being the
4208 * symbol itself) of the operation implemented by this visitor; use
4209 * Void if a second argument is not needed.
4210 */
4211 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4212 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
4213 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4214 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4215 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4216 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4217 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4218 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4219 }
4221 /**
4222 * A <em>simple</em> visitor for types. This visitor is simple as
4223 * captured wildcards, for-all types (generic methods), and
4224 * undetermined type variables (part of inference) are hidden.
4225 * Captured wildcards are hidden by treating them as type
4226 * variables and the rest are hidden by visiting their qtypes.
4227 *
4228 * @param <R> the return type of the operation implemented by this
4229 * visitor; use Void if no return type is needed.
4230 * @param <S> the type of the second argument (the first being the
4231 * type itself) of the operation implemented by this visitor; use
4232 * Void if a second argument is not needed.
4233 */
4234 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4235 @Override
4236 public R visitCapturedType(CapturedType t, S s) {
4237 return visitTypeVar(t, s);
4238 }
4239 @Override
4240 public R visitForAll(ForAll t, S s) {
4241 return visit(t.qtype, s);
4242 }
4243 @Override
4244 public R visitUndetVar(UndetVar t, S s) {
4245 return visit(t.qtype, s);
4246 }
4247 }
4249 /**
4250 * A plain relation on types. That is a 2-ary function on the
4251 * form Type × Type → Boolean.
4252 * <!-- In plain text: Type x Type -> Boolean -->
4253 */
4254 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4256 /**
4257 * A convenience visitor for implementing operations that only
4258 * require one argument (the type itself), that is, unary
4259 * operations.
4260 *
4261 * @param <R> the return type of the operation implemented by this
4262 * visitor; use Void if no return type is needed.
4263 */
4264 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4265 final public R visit(Type t) { return t.accept(this, null); }
4266 }
4268 /**
4269 * A visitor for implementing a mapping from types to types. The
4270 * default behavior of this class is to implement the identity
4271 * mapping (mapping a type to itself). This can be overridden in
4272 * subclasses.
4273 *
4274 * @param <S> the type of the second argument (the first being the
4275 * type itself) of this mapping; use Void if a second argument is
4276 * not needed.
4277 */
4278 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4279 final public Type visit(Type t) { return t.accept(this, null); }
4280 public Type visitType(Type t, S s) { return t; }
4281 }
4282 // </editor-fold>
4285 // <editor-fold defaultstate="collapsed" desc="Annotation support">
4287 public RetentionPolicy getRetention(Attribute.Compound a) {
4288 return getRetention(a.type.tsym);
4289 }
4291 public RetentionPolicy getRetention(Symbol sym) {
4292 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
4293 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
4294 if (c != null) {
4295 Attribute value = c.member(names.value);
4296 if (value != null && value instanceof Attribute.Enum) {
4297 Name levelName = ((Attribute.Enum)value).value.name;
4298 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
4299 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
4300 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
4301 else ;// /* fail soft */ throw new AssertionError(levelName);
4302 }
4303 }
4304 return vis;
4305 }
4306 // </editor-fold>
4307 }
