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src/share/classes/com/sun/tools/javac/code/Types.java@1df20330f6bd
src/share/classes/com/sun/tools/javac/code/Types.java
Wed, 06 Feb 2013 14:03:39 +0000
- author
- mcimadamore
- date
- Wed, 06 Feb 2013 14:03:39 +0000
- changeset 1550
- 1df20330f6bd
- parent 1521
- 71f35e4b93a5
- child 1563
- bc456436c613
- permissions
- -rw-r--r--
8007463: Cleanup inference related classes
Summary: Make Infer.InferenceContext an inner class; adjust bound replacement logic in Type.UndetVar
Reviewed-by: jjg
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 return isSameTypes(ts, ss, false);
980 }
981 public boolean isSameTypes(List<Type> ts, List<Type> ss, boolean strict) {
982 while (ts.tail != null && ss.tail != null
983 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
984 isSameType(ts.head, ss.head, strict)) {
985 ts = ts.tail;
986 ss = ss.tail;
987 }
988 return ts.tail == null && ss.tail == null;
989 /*inlined: ts.isEmpty() && ss.isEmpty();*/
990 }
992 /**
993 * Is t the same type as s?
994 */
995 public boolean isSameType(Type t, Type s) {
996 return isSameType(t, s, false);
997 }
998 public boolean isSameType(Type t, Type s, boolean strict) {
999 return strict ?
1000 isSameTypeStrict.visit(t, s) :
1001 isSameTypeLoose.visit(t, s);
1002 }
1003 // where
1004 abstract class SameTypeVisitor extends TypeRelation {
1006 public Boolean visitType(Type t, Type s) {
1007 if (t == s)
1008 return true;
1010 if (s.isPartial())
1011 return visit(s, t);
1013 switch (t.tag) {
1014 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1015 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
1016 return t.tag == s.tag;
1017 case TYPEVAR: {
1018 if (s.tag == TYPEVAR) {
1019 //type-substitution does not preserve type-var types
1020 //check that type var symbols and bounds are indeed the same
1021 return sameTypeVars((TypeVar)t, (TypeVar)s);
1022 }
1023 else {
1024 //special case for s == ? super X, where upper(s) = u
1025 //check that u == t, where u has been set by Type.withTypeVar
1026 return s.isSuperBound() &&
1027 !s.isExtendsBound() &&
1028 visit(t, upperBound(s));
1029 }
1030 }
1031 default:
1032 throw new AssertionError("isSameType " + t.tag);
1033 }
1034 }
1036 abstract boolean sameTypeVars(TypeVar tv1, TypeVar tv2);
1038 @Override
1039 public Boolean visitWildcardType(WildcardType t, Type s) {
1040 if (s.isPartial())
1041 return visit(s, t);
1042 else
1043 return false;
1044 }
1046 @Override
1047 public Boolean visitClassType(ClassType t, Type s) {
1048 if (t == s)
1049 return true;
1051 if (s.isPartial())
1052 return visit(s, t);
1054 if (s.isSuperBound() && !s.isExtendsBound())
1055 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
1057 if (t.isCompound() && s.isCompound()) {
1058 if (!visit(supertype(t), supertype(s)))
1059 return false;
1061 HashSet<UniqueType> set = new HashSet<UniqueType>();
1062 for (Type x : interfaces(t))
1063 set.add(new UniqueType(x, Types.this));
1064 for (Type x : interfaces(s)) {
1065 if (!set.remove(new UniqueType(x, Types.this)))
1066 return false;
1067 }
1068 return (set.isEmpty());
1069 }
1070 return t.tsym == s.tsym
1071 && visit(t.getEnclosingType(), s.getEnclosingType())
1072 && containsTypes(t.getTypeArguments(), s.getTypeArguments());
1073 }
1075 abstract protected boolean containsTypes(List<Type> ts1, List<Type> ts2);
1077 @Override
1078 public Boolean visitArrayType(ArrayType t, Type s) {
1079 if (t == s)
1080 return true;
1082 if (s.isPartial())
1083 return visit(s, t);
1085 return s.hasTag(ARRAY)
1086 && containsTypeEquivalent(t.elemtype, elemtype(s));
1087 }
1089 @Override
1090 public Boolean visitMethodType(MethodType t, Type s) {
1091 // isSameType for methods does not take thrown
1092 // exceptions into account!
1093 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
1094 }
1096 @Override
1097 public Boolean visitPackageType(PackageType t, Type s) {
1098 return t == s;
1099 }
1101 @Override
1102 public Boolean visitForAll(ForAll t, Type s) {
1103 if (s.tag != FORALL)
1104 return false;
1106 ForAll forAll = (ForAll)s;
1107 return hasSameBounds(t, forAll)
1108 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1109 }
1111 @Override
1112 public Boolean visitUndetVar(UndetVar t, Type s) {
1113 if (s.tag == WILDCARD)
1114 // FIXME, this might be leftovers from before capture conversion
1115 return false;
1117 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
1118 return true;
1120 t.addBound(InferenceBound.EQ, s, Types.this);
1122 return true;
1123 }
1125 @Override
1126 public Boolean visitErrorType(ErrorType t, Type s) {
1127 return true;
1128 }
1129 }
1131 /**
1132 * Standard type-equality relation - type variables are considered
1133 * equals if they share the same type symbol.
1134 */
1135 TypeRelation isSameTypeLoose = new SameTypeVisitor() {
1136 @Override
1137 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
1138 return tv1.tsym == tv2.tsym && visit(tv1.getUpperBound(), tv2.getUpperBound());
1139 }
1140 @Override
1141 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
1142 return containsTypeEquivalent(ts1, ts2);
1143 }
1144 };
1146 /**
1147 * Strict type-equality relation - type variables are considered
1148 * equals if they share the same object identity.
1149 */
1150 TypeRelation isSameTypeStrict = new SameTypeVisitor() {
1151 @Override
1152 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
1153 return tv1 == tv2;
1154 }
1155 @Override
1156 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
1157 return isSameTypes(ts1, ts2, true);
1158 }
1159 };
1160 // </editor-fold>
1162 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1163 public boolean containedBy(Type t, Type s) {
1164 switch (t.tag) {
1165 case UNDETVAR:
1166 if (s.tag == WILDCARD) {
1167 UndetVar undetvar = (UndetVar)t;
1168 WildcardType wt = (WildcardType)s;
1169 switch(wt.kind) {
1170 case UNBOUND: //similar to ? extends Object
1171 case EXTENDS: {
1172 Type bound = upperBound(s);
1173 undetvar.addBound(InferenceBound.UPPER, bound, this);
1174 break;
1175 }
1176 case SUPER: {
1177 Type bound = lowerBound(s);
1178 undetvar.addBound(InferenceBound.LOWER, bound, this);
1179 break;
1180 }
1181 }
1182 return true;
1183 } else {
1184 return isSameType(t, s);
1185 }
1186 case ERROR:
1187 return true;
1188 default:
1189 return containsType(s, t);
1190 }
1191 }
1193 boolean containsType(List<Type> ts, List<Type> ss) {
1194 while (ts.nonEmpty() && ss.nonEmpty()
1195 && containsType(ts.head, ss.head)) {
1196 ts = ts.tail;
1197 ss = ss.tail;
1198 }
1199 return ts.isEmpty() && ss.isEmpty();
1200 }
1202 /**
1203 * Check if t contains s.
1204 *
1205 * <p>T contains S if:
1206 *
1207 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1208 *
1209 * <p>This relation is only used by ClassType.isSubtype(), that
1210 * is,
1211 *
1212 * <p>{@code C<S> <: C<T> if T contains S.}
1213 *
1214 * <p>Because of F-bounds, this relation can lead to infinite
1215 * recursion. Thus we must somehow break that recursion. Notice
1216 * that containsType() is only called from ClassType.isSubtype().
1217 * Since the arguments have already been checked against their
1218 * bounds, we know:
1219 *
1220 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1221 *
1222 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1223 *
1224 * @param t a type
1225 * @param s a type
1226 */
1227 public boolean containsType(Type t, Type s) {
1228 return containsType.visit(t, s);
1229 }
1230 // where
1231 private TypeRelation containsType = new TypeRelation() {
1233 private Type U(Type t) {
1234 while (t.tag == WILDCARD) {
1235 WildcardType w = (WildcardType)t;
1236 if (w.isSuperBound())
1237 return w.bound == null ? syms.objectType : w.bound.bound;
1238 else
1239 t = w.type;
1240 }
1241 return t;
1242 }
1244 private Type L(Type t) {
1245 while (t.tag == WILDCARD) {
1246 WildcardType w = (WildcardType)t;
1247 if (w.isExtendsBound())
1248 return syms.botType;
1249 else
1250 t = w.type;
1251 }
1252 return t;
1253 }
1255 public Boolean visitType(Type t, Type s) {
1256 if (s.isPartial())
1257 return containedBy(s, t);
1258 else
1259 return isSameType(t, s);
1260 }
1262 // void debugContainsType(WildcardType t, Type s) {
1263 // System.err.println();
1264 // System.err.format(" does %s contain %s?%n", t, s);
1265 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1266 // upperBound(s), s, t, U(t),
1267 // t.isSuperBound()
1268 // || isSubtypeNoCapture(upperBound(s), U(t)));
1269 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1270 // L(t), t, s, lowerBound(s),
1271 // t.isExtendsBound()
1272 // || isSubtypeNoCapture(L(t), lowerBound(s)));
1273 // System.err.println();
1274 // }
1276 @Override
1277 public Boolean visitWildcardType(WildcardType t, Type s) {
1278 if (s.isPartial())
1279 return containedBy(s, t);
1280 else {
1281 // debugContainsType(t, s);
1282 return isSameWildcard(t, s)
1283 || isCaptureOf(s, t)
1284 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
1285 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
1286 }
1287 }
1289 @Override
1290 public Boolean visitUndetVar(UndetVar t, Type s) {
1291 if (s.tag != WILDCARD)
1292 return isSameType(t, s);
1293 else
1294 return false;
1295 }
1297 @Override
1298 public Boolean visitErrorType(ErrorType t, Type s) {
1299 return true;
1300 }
1301 };
1303 public boolean isCaptureOf(Type s, WildcardType t) {
1304 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
1305 return false;
1306 return isSameWildcard(t, ((CapturedType)s).wildcard);
1307 }
1309 public boolean isSameWildcard(WildcardType t, Type s) {
1310 if (s.tag != WILDCARD)
1311 return false;
1312 WildcardType w = (WildcardType)s;
1313 return w.kind == t.kind && w.type == t.type;
1314 }
1316 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1317 while (ts.nonEmpty() && ss.nonEmpty()
1318 && containsTypeEquivalent(ts.head, ss.head)) {
1319 ts = ts.tail;
1320 ss = ss.tail;
1321 }
1322 return ts.isEmpty() && ss.isEmpty();
1323 }
1324 // </editor-fold>
1326 // <editor-fold defaultstate="collapsed" desc="isCastable">
1327 public boolean isCastable(Type t, Type s) {
1328 return isCastable(t, s, noWarnings);
1329 }
1331 /**
1332 * Is t is castable to s?<br>
1333 * s is assumed to be an erased type.<br>
1334 * (not defined for Method and ForAll types).
1335 */
1336 public boolean isCastable(Type t, Type s, Warner warn) {
1337 if (t == s)
1338 return true;
1340 if (t.isPrimitive() != s.isPrimitive())
1341 return allowBoxing && (
1342 isConvertible(t, s, warn)
1343 || (allowObjectToPrimitiveCast &&
1344 s.isPrimitive() &&
1345 isSubtype(boxedClass(s).type, t)));
1346 if (warn != warnStack.head) {
1347 try {
1348 warnStack = warnStack.prepend(warn);
1349 checkUnsafeVarargsConversion(t, s, warn);
1350 return isCastable.visit(t,s);
1351 } finally {
1352 warnStack = warnStack.tail;
1353 }
1354 } else {
1355 return isCastable.visit(t,s);
1356 }
1357 }
1358 // where
1359 private TypeRelation isCastable = new TypeRelation() {
1361 public Boolean visitType(Type t, Type s) {
1362 if (s.tag == ERROR)
1363 return true;
1365 switch (t.tag) {
1366 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1367 case DOUBLE:
1368 return s.isNumeric();
1369 case BOOLEAN:
1370 return s.tag == BOOLEAN;
1371 case VOID:
1372 return false;
1373 case BOT:
1374 return isSubtype(t, s);
1375 default:
1376 throw new AssertionError();
1377 }
1378 }
1380 @Override
1381 public Boolean visitWildcardType(WildcardType t, Type s) {
1382 return isCastable(upperBound(t), s, warnStack.head);
1383 }
1385 @Override
1386 public Boolean visitClassType(ClassType t, Type s) {
1387 if (s.tag == ERROR || s.tag == BOT)
1388 return true;
1390 if (s.tag == TYPEVAR) {
1391 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1392 warnStack.head.warn(LintCategory.UNCHECKED);
1393 return true;
1394 } else {
1395 return false;
1396 }
1397 }
1399 if (t.isCompound()) {
1400 Warner oldWarner = warnStack.head;
1401 warnStack.head = noWarnings;
1402 if (!visit(supertype(t), s))
1403 return false;
1404 for (Type intf : interfaces(t)) {
1405 if (!visit(intf, s))
1406 return false;
1407 }
1408 if (warnStack.head.hasLint(LintCategory.UNCHECKED))
1409 oldWarner.warn(LintCategory.UNCHECKED);
1410 return true;
1411 }
1413 if (s.isCompound()) {
1414 // call recursively to reuse the above code
1415 return visitClassType((ClassType)s, t);
1416 }
1418 if (s.tag == CLASS || s.tag == ARRAY) {
1419 boolean upcast;
1420 if ((upcast = isSubtype(erasure(t), erasure(s)))
1421 || isSubtype(erasure(s), erasure(t))) {
1422 if (!upcast && s.tag == ARRAY) {
1423 if (!isReifiable(s))
1424 warnStack.head.warn(LintCategory.UNCHECKED);
1425 return true;
1426 } else if (s.isRaw()) {
1427 return true;
1428 } else if (t.isRaw()) {
1429 if (!isUnbounded(s))
1430 warnStack.head.warn(LintCategory.UNCHECKED);
1431 return true;
1432 }
1433 // Assume |a| <: |b|
1434 final Type a = upcast ? t : s;
1435 final Type b = upcast ? s : t;
1436 final boolean HIGH = true;
1437 final boolean LOW = false;
1438 final boolean DONT_REWRITE_TYPEVARS = false;
1439 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1440 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1441 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1442 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1443 Type lowSub = asSub(bLow, aLow.tsym);
1444 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1445 if (highSub == null) {
1446 final boolean REWRITE_TYPEVARS = true;
1447 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1448 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1449 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1450 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1451 lowSub = asSub(bLow, aLow.tsym);
1452 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1453 }
1454 if (highSub != null) {
1455 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1456 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1457 }
1458 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1459 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1460 && !disjointTypes(aLow.allparams(), highSub.allparams())
1461 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1462 if (upcast ? giveWarning(a, b) :
1463 giveWarning(b, a))
1464 warnStack.head.warn(LintCategory.UNCHECKED);
1465 return true;
1466 }
1467 }
1468 if (isReifiable(s))
1469 return isSubtypeUnchecked(a, b);
1470 else
1471 return isSubtypeUnchecked(a, b, warnStack.head);
1472 }
1474 // Sidecast
1475 if (s.tag == CLASS) {
1476 if ((s.tsym.flags() & INTERFACE) != 0) {
1477 return ((t.tsym.flags() & FINAL) == 0)
1478 ? sideCast(t, s, warnStack.head)
1479 : sideCastFinal(t, s, warnStack.head);
1480 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1481 return ((s.tsym.flags() & FINAL) == 0)
1482 ? sideCast(t, s, warnStack.head)
1483 : sideCastFinal(t, s, warnStack.head);
1484 } else {
1485 // unrelated class types
1486 return false;
1487 }
1488 }
1489 }
1490 return false;
1491 }
1493 @Override
1494 public Boolean visitArrayType(ArrayType t, Type s) {
1495 switch (s.tag) {
1496 case ERROR:
1497 case BOT:
1498 return true;
1499 case TYPEVAR:
1500 if (isCastable(s, t, noWarnings)) {
1501 warnStack.head.warn(LintCategory.UNCHECKED);
1502 return true;
1503 } else {
1504 return false;
1505 }
1506 case CLASS:
1507 return isSubtype(t, s);
1508 case ARRAY:
1509 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1510 return elemtype(t).tag == elemtype(s).tag;
1511 } else {
1512 return visit(elemtype(t), elemtype(s));
1513 }
1514 default:
1515 return false;
1516 }
1517 }
1519 @Override
1520 public Boolean visitTypeVar(TypeVar t, Type s) {
1521 switch (s.tag) {
1522 case ERROR:
1523 case BOT:
1524 return true;
1525 case TYPEVAR:
1526 if (isSubtype(t, s)) {
1527 return true;
1528 } else if (isCastable(t.bound, s, noWarnings)) {
1529 warnStack.head.warn(LintCategory.UNCHECKED);
1530 return true;
1531 } else {
1532 return false;
1533 }
1534 default:
1535 return isCastable(t.bound, s, warnStack.head);
1536 }
1537 }
1539 @Override
1540 public Boolean visitErrorType(ErrorType t, Type s) {
1541 return true;
1542 }
1543 };
1544 // </editor-fold>
1546 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1547 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1548 while (ts.tail != null && ss.tail != null) {
1549 if (disjointType(ts.head, ss.head)) return true;
1550 ts = ts.tail;
1551 ss = ss.tail;
1552 }
1553 return false;
1554 }
1556 /**
1557 * Two types or wildcards are considered disjoint if it can be
1558 * proven that no type can be contained in both. It is
1559 * conservative in that it is allowed to say that two types are
1560 * not disjoint, even though they actually are.
1561 *
1562 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1563 * {@code X} and {@code Y} are not disjoint.
1564 */
1565 public boolean disjointType(Type t, Type s) {
1566 return disjointType.visit(t, s);
1567 }
1568 // where
1569 private TypeRelation disjointType = new TypeRelation() {
1571 private Set<TypePair> cache = new HashSet<TypePair>();
1573 public Boolean visitType(Type t, Type s) {
1574 if (s.tag == WILDCARD)
1575 return visit(s, t);
1576 else
1577 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1578 }
1580 private boolean isCastableRecursive(Type t, Type s) {
1581 TypePair pair = new TypePair(t, s);
1582 if (cache.add(pair)) {
1583 try {
1584 return Types.this.isCastable(t, s);
1585 } finally {
1586 cache.remove(pair);
1587 }
1588 } else {
1589 return true;
1590 }
1591 }
1593 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1594 TypePair pair = new TypePair(t, s);
1595 if (cache.add(pair)) {
1596 try {
1597 return Types.this.notSoftSubtype(t, s);
1598 } finally {
1599 cache.remove(pair);
1600 }
1601 } else {
1602 return false;
1603 }
1604 }
1606 @Override
1607 public Boolean visitWildcardType(WildcardType t, Type s) {
1608 if (t.isUnbound())
1609 return false;
1611 if (s.tag != WILDCARD) {
1612 if (t.isExtendsBound())
1613 return notSoftSubtypeRecursive(s, t.type);
1614 else // isSuperBound()
1615 return notSoftSubtypeRecursive(t.type, s);
1616 }
1618 if (s.isUnbound())
1619 return false;
1621 if (t.isExtendsBound()) {
1622 if (s.isExtendsBound())
1623 return !isCastableRecursive(t.type, upperBound(s));
1624 else if (s.isSuperBound())
1625 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1626 } else if (t.isSuperBound()) {
1627 if (s.isExtendsBound())
1628 return notSoftSubtypeRecursive(t.type, upperBound(s));
1629 }
1630 return false;
1631 }
1632 };
1633 // </editor-fold>
1635 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1636 /**
1637 * Returns the lower bounds of the formals of a method.
1638 */
1639 public List<Type> lowerBoundArgtypes(Type t) {
1640 return lowerBounds(t.getParameterTypes());
1641 }
1642 public List<Type> lowerBounds(List<Type> ts) {
1643 return map(ts, lowerBoundMapping);
1644 }
1645 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1646 public Type apply(Type t) {
1647 return lowerBound(t);
1648 }
1649 };
1650 // </editor-fold>
1652 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1653 /**
1654 * This relation answers the question: is impossible that
1655 * something of type `t' can be a subtype of `s'? This is
1656 * different from the question "is `t' not a subtype of `s'?"
1657 * when type variables are involved: Integer is not a subtype of T
1658 * where {@code <T extends Number>} but it is not true that Integer cannot
1659 * possibly be a subtype of T.
1660 */
1661 public boolean notSoftSubtype(Type t, Type s) {
1662 if (t == s) return false;
1663 if (t.tag == TYPEVAR) {
1664 TypeVar tv = (TypeVar) t;
1665 return !isCastable(tv.bound,
1666 relaxBound(s),
1667 noWarnings);
1668 }
1669 if (s.tag != WILDCARD)
1670 s = upperBound(s);
1672 return !isSubtype(t, relaxBound(s));
1673 }
1675 private Type relaxBound(Type t) {
1676 if (t.tag == TYPEVAR) {
1677 while (t.tag == TYPEVAR)
1678 t = t.getUpperBound();
1679 t = rewriteQuantifiers(t, true, true);
1680 }
1681 return t;
1682 }
1683 // </editor-fold>
1685 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1686 public boolean isReifiable(Type t) {
1687 return isReifiable.visit(t);
1688 }
1689 // where
1690 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1692 public Boolean visitType(Type t, Void ignored) {
1693 return true;
1694 }
1696 @Override
1697 public Boolean visitClassType(ClassType t, Void ignored) {
1698 if (t.isCompound())
1699 return false;
1700 else {
1701 if (!t.isParameterized())
1702 return true;
1704 for (Type param : t.allparams()) {
1705 if (!param.isUnbound())
1706 return false;
1707 }
1708 return true;
1709 }
1710 }
1712 @Override
1713 public Boolean visitArrayType(ArrayType t, Void ignored) {
1714 return visit(t.elemtype);
1715 }
1717 @Override
1718 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1719 return false;
1720 }
1721 };
1722 // </editor-fold>
1724 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1725 public boolean isArray(Type t) {
1726 while (t.tag == WILDCARD)
1727 t = upperBound(t);
1728 return t.tag == ARRAY;
1729 }
1731 /**
1732 * The element type of an array.
1733 */
1734 public Type elemtype(Type t) {
1735 switch (t.tag) {
1736 case WILDCARD:
1737 return elemtype(upperBound(t));
1738 case ARRAY:
1739 t = t.unannotatedType();
1740 return ((ArrayType)t).elemtype;
1741 case FORALL:
1742 return elemtype(((ForAll)t).qtype);
1743 case ERROR:
1744 return t;
1745 default:
1746 return null;
1747 }
1748 }
1750 public Type elemtypeOrType(Type t) {
1751 Type elemtype = elemtype(t);
1752 return elemtype != null ?
1753 elemtype :
1754 t;
1755 }
1757 /**
1758 * Mapping to take element type of an arraytype
1759 */
1760 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1761 public Type apply(Type t) { return elemtype(t); }
1762 };
1764 /**
1765 * The number of dimensions of an array type.
1766 */
1767 public int dimensions(Type t) {
1768 int result = 0;
1769 while (t.tag == ARRAY) {
1770 result++;
1771 t = elemtype(t);
1772 }
1773 return result;
1774 }
1776 /**
1777 * Returns an ArrayType with the component type t
1778 *
1779 * @param t The component type of the ArrayType
1780 * @return the ArrayType for the given component
1781 */
1782 public ArrayType makeArrayType(Type t) {
1783 if (t.tag == VOID ||
1784 t.tag == PACKAGE) {
1785 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
1786 }
1787 return new ArrayType(t, syms.arrayClass);
1788 }
1789 // </editor-fold>
1791 // <editor-fold defaultstate="collapsed" desc="asSuper">
1792 /**
1793 * Return the (most specific) base type of t that starts with the
1794 * given symbol. If none exists, return null.
1795 *
1796 * @param t a type
1797 * @param sym a symbol
1798 */
1799 public Type asSuper(Type t, Symbol sym) {
1800 return asSuper.visit(t, sym);
1801 }
1802 // where
1803 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1805 public Type visitType(Type t, Symbol sym) {
1806 return null;
1807 }
1809 @Override
1810 public Type visitClassType(ClassType t, Symbol sym) {
1811 if (t.tsym == sym)
1812 return t;
1814 Type st = supertype(t);
1815 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1816 Type x = asSuper(st, sym);
1817 if (x != null)
1818 return x;
1819 }
1820 if ((sym.flags() & INTERFACE) != 0) {
1821 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1822 Type x = asSuper(l.head, sym);
1823 if (x != null)
1824 return x;
1825 }
1826 }
1827 return null;
1828 }
1830 @Override
1831 public Type visitArrayType(ArrayType t, Symbol sym) {
1832 return isSubtype(t, sym.type) ? sym.type : null;
1833 }
1835 @Override
1836 public Type visitTypeVar(TypeVar t, Symbol sym) {
1837 if (t.tsym == sym)
1838 return t;
1839 else
1840 return asSuper(t.bound, sym);
1841 }
1843 @Override
1844 public Type visitErrorType(ErrorType t, Symbol sym) {
1845 return t;
1846 }
1847 };
1849 /**
1850 * Return the base type of t or any of its outer types that starts
1851 * with the given symbol. If none exists, return null.
1852 *
1853 * @param t a type
1854 * @param sym a symbol
1855 */
1856 public Type asOuterSuper(Type t, Symbol sym) {
1857 switch (t.tag) {
1858 case CLASS:
1859 do {
1860 Type s = asSuper(t, sym);
1861 if (s != null) return s;
1862 t = t.getEnclosingType();
1863 } while (t.tag == CLASS);
1864 return null;
1865 case ARRAY:
1866 return isSubtype(t, sym.type) ? sym.type : null;
1867 case TYPEVAR:
1868 return asSuper(t, sym);
1869 case ERROR:
1870 return t;
1871 default:
1872 return null;
1873 }
1874 }
1876 /**
1877 * Return the base type of t or any of its enclosing types that
1878 * starts with the given symbol. If none exists, return null.
1879 *
1880 * @param t a type
1881 * @param sym a symbol
1882 */
1883 public Type asEnclosingSuper(Type t, Symbol sym) {
1884 switch (t.tag) {
1885 case CLASS:
1886 do {
1887 Type s = asSuper(t, sym);
1888 if (s != null) return s;
1889 Type outer = t.getEnclosingType();
1890 t = (outer.tag == CLASS) ? outer :
1891 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1892 Type.noType;
1893 } while (t.tag == CLASS);
1894 return null;
1895 case ARRAY:
1896 return isSubtype(t, sym.type) ? sym.type : null;
1897 case TYPEVAR:
1898 return asSuper(t, sym);
1899 case ERROR:
1900 return t;
1901 default:
1902 return null;
1903 }
1904 }
1905 // </editor-fold>
1907 // <editor-fold defaultstate="collapsed" desc="memberType">
1908 /**
1909 * The type of given symbol, seen as a member of t.
1910 *
1911 * @param t a type
1912 * @param sym a symbol
1913 */
1914 public Type memberType(Type t, Symbol sym) {
1915 return (sym.flags() & STATIC) != 0
1916 ? sym.type
1917 : memberType.visit(t, sym);
1918 }
1919 // where
1920 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1922 public Type visitType(Type t, Symbol sym) {
1923 return sym.type;
1924 }
1926 @Override
1927 public Type visitWildcardType(WildcardType t, Symbol sym) {
1928 return memberType(upperBound(t), sym);
1929 }
1931 @Override
1932 public Type visitClassType(ClassType t, Symbol sym) {
1933 Symbol owner = sym.owner;
1934 long flags = sym.flags();
1935 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1936 Type base = asOuterSuper(t, owner);
1937 //if t is an intersection type T = CT & I1 & I2 ... & In
1938 //its supertypes CT, I1, ... In might contain wildcards
1939 //so we need to go through capture conversion
1940 base = t.isCompound() ? capture(base) : base;
1941 if (base != null) {
1942 List<Type> ownerParams = owner.type.allparams();
1943 List<Type> baseParams = base.allparams();
1944 if (ownerParams.nonEmpty()) {
1945 if (baseParams.isEmpty()) {
1946 // then base is a raw type
1947 return erasure(sym.type);
1948 } else {
1949 return subst(sym.type, ownerParams, baseParams);
1950 }
1951 }
1952 }
1953 }
1954 return sym.type;
1955 }
1957 @Override
1958 public Type visitTypeVar(TypeVar t, Symbol sym) {
1959 return memberType(t.bound, sym);
1960 }
1962 @Override
1963 public Type visitErrorType(ErrorType t, Symbol sym) {
1964 return t;
1965 }
1966 };
1967 // </editor-fold>
1969 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1970 public boolean isAssignable(Type t, Type s) {
1971 return isAssignable(t, s, noWarnings);
1972 }
1974 /**
1975 * Is t assignable to s?<br>
1976 * Equivalent to subtype except for constant values and raw
1977 * types.<br>
1978 * (not defined for Method and ForAll types)
1979 */
1980 public boolean isAssignable(Type t, Type s, Warner warn) {
1981 if (t.tag == ERROR)
1982 return true;
1983 if (t.tag.isSubRangeOf(INT) && t.constValue() != null) {
1984 int value = ((Number)t.constValue()).intValue();
1985 switch (s.tag) {
1986 case BYTE:
1987 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1988 return true;
1989 break;
1990 case CHAR:
1991 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1992 return true;
1993 break;
1994 case SHORT:
1995 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1996 return true;
1997 break;
1998 case INT:
1999 return true;
2000 case CLASS:
2001 switch (unboxedType(s).tag) {
2002 case BYTE:
2003 case CHAR:
2004 case SHORT:
2005 return isAssignable(t, unboxedType(s), warn);
2006 }
2007 break;
2008 }
2009 }
2010 return isConvertible(t, s, warn);
2011 }
2012 // </editor-fold>
2014 // <editor-fold defaultstate="collapsed" desc="erasure">
2015 /**
2016 * The erasure of t {@code |t|} -- the type that results when all
2017 * type parameters in t are deleted.
2018 */
2019 public Type erasure(Type t) {
2020 return eraseNotNeeded(t)? t : erasure(t, false);
2021 }
2022 //where
2023 private boolean eraseNotNeeded(Type t) {
2024 // We don't want to erase primitive types and String type as that
2025 // operation is idempotent. Also, erasing these could result in loss
2026 // of information such as constant values attached to such types.
2027 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2028 }
2030 private Type erasure(Type t, boolean recurse) {
2031 if (t.isPrimitive())
2032 return t; /* fast special case */
2033 else
2034 return erasure.visit(t, recurse);
2035 }
2036 // where
2037 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
2038 public Type visitType(Type t, Boolean recurse) {
2039 if (t.isPrimitive())
2040 return t; /*fast special case*/
2041 else
2042 return t.map(recurse ? erasureRecFun : erasureFun);
2043 }
2045 @Override
2046 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2047 return erasure(upperBound(t), recurse);
2048 }
2050 @Override
2051 public Type visitClassType(ClassType t, Boolean recurse) {
2052 Type erased = t.tsym.erasure(Types.this);
2053 if (recurse) {
2054 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
2055 }
2056 return erased;
2057 }
2059 @Override
2060 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2061 return erasure(t.bound, recurse);
2062 }
2064 @Override
2065 public Type visitErrorType(ErrorType t, Boolean recurse) {
2066 return t;
2067 }
2069 @Override
2070 public Type visitAnnotatedType(AnnotatedType t, Boolean recurse) {
2071 return new AnnotatedType(t.typeAnnotations, erasure(t.underlyingType, recurse));
2072 }
2073 };
2075 private Mapping erasureFun = new Mapping ("erasure") {
2076 public Type apply(Type t) { return erasure(t); }
2077 };
2079 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
2080 public Type apply(Type t) { return erasureRecursive(t); }
2081 };
2083 public List<Type> erasure(List<Type> ts) {
2084 return Type.map(ts, erasureFun);
2085 }
2087 public Type erasureRecursive(Type t) {
2088 return erasure(t, true);
2089 }
2091 public List<Type> erasureRecursive(List<Type> ts) {
2092 return Type.map(ts, erasureRecFun);
2093 }
2094 // </editor-fold>
2096 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
2097 /**
2098 * Make a compound type from non-empty list of types
2099 *
2100 * @param bounds the types from which the compound type is formed
2101 * @param supertype is objectType if all bounds are interfaces,
2102 * null otherwise.
2103 */
2104 public Type makeCompoundType(List<Type> bounds) {
2105 return makeCompoundType(bounds, bounds.head.tsym.isInterface());
2106 }
2107 public Type makeCompoundType(List<Type> bounds, boolean allInterfaces) {
2108 Assert.check(bounds.nonEmpty());
2109 Type firstExplicitBound = bounds.head;
2110 if (allInterfaces) {
2111 bounds = bounds.prepend(syms.objectType);
2112 }
2113 ClassSymbol bc =
2114 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2115 Type.moreInfo
2116 ? names.fromString(bounds.toString())
2117 : names.empty,
2118 null,
2119 syms.noSymbol);
2120 bc.type = new IntersectionClassType(bounds, bc, allInterfaces);
2121 bc.erasure_field = (bounds.head.tag == TYPEVAR) ?
2122 syms.objectType : // error condition, recover
2123 erasure(firstExplicitBound);
2124 bc.members_field = new Scope(bc);
2125 return bc.type;
2126 }
2128 /**
2129 * A convenience wrapper for {@link #makeCompoundType(List)}; the
2130 * arguments are converted to a list and passed to the other
2131 * method. Note that this might cause a symbol completion.
2132 * Hence, this version of makeCompoundType may not be called
2133 * during a classfile read.
2134 */
2135 public Type makeCompoundType(Type bound1, Type bound2) {
2136 return makeCompoundType(List.of(bound1, bound2));
2137 }
2138 // </editor-fold>
2140 // <editor-fold defaultstate="collapsed" desc="supertype">
2141 public Type supertype(Type t) {
2142 return supertype.visit(t);
2143 }
2144 // where
2145 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2147 public Type visitType(Type t, Void ignored) {
2148 // A note on wildcards: there is no good way to
2149 // determine a supertype for a super bounded wildcard.
2150 return null;
2151 }
2153 @Override
2154 public Type visitClassType(ClassType t, Void ignored) {
2155 if (t.supertype_field == null) {
2156 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2157 // An interface has no superclass; its supertype is Object.
2158 if (t.isInterface())
2159 supertype = ((ClassType)t.tsym.type).supertype_field;
2160 if (t.supertype_field == null) {
2161 List<Type> actuals = classBound(t).allparams();
2162 List<Type> formals = t.tsym.type.allparams();
2163 if (t.hasErasedSupertypes()) {
2164 t.supertype_field = erasureRecursive(supertype);
2165 } else if (formals.nonEmpty()) {
2166 t.supertype_field = subst(supertype, formals, actuals);
2167 }
2168 else {
2169 t.supertype_field = supertype;
2170 }
2171 }
2172 }
2173 return t.supertype_field;
2174 }
2176 /**
2177 * The supertype is always a class type. If the type
2178 * variable's bounds start with a class type, this is also
2179 * the supertype. Otherwise, the supertype is
2180 * java.lang.Object.
2181 */
2182 @Override
2183 public Type visitTypeVar(TypeVar t, Void ignored) {
2184 if (t.bound.tag == TYPEVAR ||
2185 (!t.bound.isCompound() && !t.bound.isInterface())) {
2186 return t.bound;
2187 } else {
2188 return supertype(t.bound);
2189 }
2190 }
2192 @Override
2193 public Type visitArrayType(ArrayType t, Void ignored) {
2194 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2195 return arraySuperType();
2196 else
2197 return new ArrayType(supertype(t.elemtype), t.tsym);
2198 }
2200 @Override
2201 public Type visitErrorType(ErrorType t, Void ignored) {
2202 return t;
2203 }
2204 };
2205 // </editor-fold>
2207 // <editor-fold defaultstate="collapsed" desc="interfaces">
2208 /**
2209 * Return the interfaces implemented by this class.
2210 */
2211 public List<Type> interfaces(Type t) {
2212 return interfaces.visit(t);
2213 }
2214 // where
2215 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2217 public List<Type> visitType(Type t, Void ignored) {
2218 return List.nil();
2219 }
2221 @Override
2222 public List<Type> visitClassType(ClassType t, Void ignored) {
2223 if (t.interfaces_field == null) {
2224 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2225 if (t.interfaces_field == null) {
2226 // If t.interfaces_field is null, then t must
2227 // be a parameterized type (not to be confused
2228 // with a generic type declaration).
2229 // Terminology:
2230 // Parameterized type: List<String>
2231 // Generic type declaration: class List<E> { ... }
2232 // So t corresponds to List<String> and
2233 // t.tsym.type corresponds to List<E>.
2234 // The reason t must be parameterized type is
2235 // that completion will happen as a side
2236 // effect of calling
2237 // ClassSymbol.getInterfaces. Since
2238 // t.interfaces_field is null after
2239 // completion, we can assume that t is not the
2240 // type of a class/interface declaration.
2241 Assert.check(t != t.tsym.type, t);
2242 List<Type> actuals = t.allparams();
2243 List<Type> formals = t.tsym.type.allparams();
2244 if (t.hasErasedSupertypes()) {
2245 t.interfaces_field = erasureRecursive(interfaces);
2246 } else if (formals.nonEmpty()) {
2247 t.interfaces_field =
2248 upperBounds(subst(interfaces, formals, actuals));
2249 }
2250 else {
2251 t.interfaces_field = interfaces;
2252 }
2253 }
2254 }
2255 return t.interfaces_field;
2256 }
2258 @Override
2259 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2260 if (t.bound.isCompound())
2261 return interfaces(t.bound);
2263 if (t.bound.isInterface())
2264 return List.of(t.bound);
2266 return List.nil();
2267 }
2268 };
2270 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2271 for (Type i2 : interfaces(origin.type)) {
2272 if (isym == i2.tsym) return true;
2273 }
2274 return false;
2275 }
2276 // </editor-fold>
2278 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2279 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
2281 public boolean isDerivedRaw(Type t) {
2282 Boolean result = isDerivedRawCache.get(t);
2283 if (result == null) {
2284 result = isDerivedRawInternal(t);
2285 isDerivedRawCache.put(t, result);
2286 }
2287 return result;
2288 }
2290 public boolean isDerivedRawInternal(Type t) {
2291 if (t.isErroneous())
2292 return false;
2293 return
2294 t.isRaw() ||
2295 supertype(t) != null && isDerivedRaw(supertype(t)) ||
2296 isDerivedRaw(interfaces(t));
2297 }
2299 public boolean isDerivedRaw(List<Type> ts) {
2300 List<Type> l = ts;
2301 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2302 return l.nonEmpty();
2303 }
2304 // </editor-fold>
2306 // <editor-fold defaultstate="collapsed" desc="setBounds">
2307 /**
2308 * Set the bounds field of the given type variable to reflect a
2309 * (possibly multiple) list of bounds.
2310 * @param t a type variable
2311 * @param bounds the bounds, must be nonempty
2312 * @param supertype is objectType if all bounds are interfaces,
2313 * null otherwise.
2314 */
2315 public void setBounds(TypeVar t, List<Type> bounds) {
2316 setBounds(t, bounds, bounds.head.tsym.isInterface());
2317 }
2319 /**
2320 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
2321 * third parameter is computed directly, as follows: if all
2322 * all bounds are interface types, the computed supertype is Object,
2323 * otherwise the supertype is simply left null (in this case, the supertype
2324 * is assumed to be the head of the bound list passed as second argument).
2325 * Note that this check might cause a symbol completion. Hence, this version of
2326 * setBounds may not be called during a classfile read.
2327 */
2328 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2329 t.bound = bounds.tail.isEmpty() ?
2330 bounds.head :
2331 makeCompoundType(bounds, allInterfaces);
2332 t.rank_field = -1;
2333 }
2334 // </editor-fold>
2336 // <editor-fold defaultstate="collapsed" desc="getBounds">
2337 /**
2338 * Return list of bounds of the given type variable.
2339 */
2340 public List<Type> getBounds(TypeVar t) {
2341 if (t.bound.hasTag(NONE))
2342 return List.nil();
2343 else if (t.bound.isErroneous() || !t.bound.isCompound())
2344 return List.of(t.bound);
2345 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2346 return interfaces(t).prepend(supertype(t));
2347 else
2348 // No superclass was given in bounds.
2349 // In this case, supertype is Object, erasure is first interface.
2350 return interfaces(t);
2351 }
2352 // </editor-fold>
2354 // <editor-fold defaultstate="collapsed" desc="classBound">
2355 /**
2356 * If the given type is a (possibly selected) type variable,
2357 * return the bounding class of this type, otherwise return the
2358 * type itself.
2359 */
2360 public Type classBound(Type t) {
2361 return classBound.visit(t);
2362 }
2363 // where
2364 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2366 public Type visitType(Type t, Void ignored) {
2367 return t;
2368 }
2370 @Override
2371 public Type visitClassType(ClassType t, Void ignored) {
2372 Type outer1 = classBound(t.getEnclosingType());
2373 if (outer1 != t.getEnclosingType())
2374 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
2375 else
2376 return t;
2377 }
2379 @Override
2380 public Type visitTypeVar(TypeVar t, Void ignored) {
2381 return classBound(supertype(t));
2382 }
2384 @Override
2385 public Type visitErrorType(ErrorType t, Void ignored) {
2386 return t;
2387 }
2388 };
2389 // </editor-fold>
2391 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
2392 /**
2393 * Returns true iff the first signature is a <em>sub
2394 * signature</em> of the other. This is <b>not</b> an equivalence
2395 * relation.
2396 *
2397 * @jls section 8.4.2.
2398 * @see #overrideEquivalent(Type t, Type s)
2399 * @param t first signature (possibly raw).
2400 * @param s second signature (could be subjected to erasure).
2401 * @return true if t is a sub signature of s.
2402 */
2403 public boolean isSubSignature(Type t, Type s) {
2404 return isSubSignature(t, s, true);
2405 }
2407 public boolean isSubSignature(Type t, Type s, boolean strict) {
2408 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2409 }
2411 /**
2412 * Returns true iff these signatures are related by <em>override
2413 * equivalence</em>. This is the natural extension of
2414 * isSubSignature to an equivalence relation.
2415 *
2416 * @jls section 8.4.2.
2417 * @see #isSubSignature(Type t, Type s)
2418 * @param t a signature (possible raw, could be subjected to
2419 * erasure).
2420 * @param s a signature (possible raw, could be subjected to
2421 * erasure).
2422 * @return true if either argument is a sub signature of the other.
2423 */
2424 public boolean overrideEquivalent(Type t, Type s) {
2425 return hasSameArgs(t, s) ||
2426 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2427 }
2429 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2430 for (Scope.Entry e = syms.objectType.tsym.members().lookup(msym.name) ; e.scope != null ; e = e.next()) {
2431 if (msym.overrides(e.sym, origin, Types.this, true)) {
2432 return true;
2433 }
2434 }
2435 return false;
2436 }
2438 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2439 class ImplementationCache {
2441 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
2442 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
2444 class Entry {
2445 final MethodSymbol cachedImpl;
2446 final Filter<Symbol> implFilter;
2447 final boolean checkResult;
2448 final int prevMark;
2450 public Entry(MethodSymbol cachedImpl,
2451 Filter<Symbol> scopeFilter,
2452 boolean checkResult,
2453 int prevMark) {
2454 this.cachedImpl = cachedImpl;
2455 this.implFilter = scopeFilter;
2456 this.checkResult = checkResult;
2457 this.prevMark = prevMark;
2458 }
2460 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
2461 return this.implFilter == scopeFilter &&
2462 this.checkResult == checkResult &&
2463 this.prevMark == mark;
2464 }
2465 }
2467 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2468 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2469 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2470 if (cache == null) {
2471 cache = new HashMap<TypeSymbol, Entry>();
2472 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2473 }
2474 Entry e = cache.get(origin);
2475 CompoundScope members = membersClosure(origin.type, true);
2476 if (e == null ||
2477 !e.matches(implFilter, checkResult, members.getMark())) {
2478 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2479 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2480 return impl;
2481 }
2482 else {
2483 return e.cachedImpl;
2484 }
2485 }
2487 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2488 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = supertype(t)) {
2489 while (t.tag == TYPEVAR)
2490 t = t.getUpperBound();
2491 TypeSymbol c = t.tsym;
2492 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2493 e.scope != null;
2494 e = e.next(implFilter)) {
2495 if (e.sym != null &&
2496 e.sym.overrides(ms, origin, Types.this, checkResult))
2497 return (MethodSymbol)e.sym;
2498 }
2499 }
2500 return null;
2501 }
2502 }
2504 private ImplementationCache implCache = new ImplementationCache();
2506 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2507 return implCache.get(ms, origin, checkResult, implFilter);
2508 }
2509 // </editor-fold>
2511 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2512 class MembersClosureCache extends SimpleVisitor<CompoundScope, Boolean> {
2514 private WeakHashMap<TypeSymbol, Entry> _map =
2515 new WeakHashMap<TypeSymbol, Entry>();
2517 class Entry {
2518 final boolean skipInterfaces;
2519 final CompoundScope compoundScope;
2521 public Entry(boolean skipInterfaces, CompoundScope compoundScope) {
2522 this.skipInterfaces = skipInterfaces;
2523 this.compoundScope = compoundScope;
2524 }
2526 boolean matches(boolean skipInterfaces) {
2527 return this.skipInterfaces == skipInterfaces;
2528 }
2529 }
2531 List<TypeSymbol> seenTypes = List.nil();
2533 /** members closure visitor methods **/
2535 public CompoundScope visitType(Type t, Boolean skipInterface) {
2536 return null;
2537 }
2539 @Override
2540 public CompoundScope visitClassType(ClassType t, Boolean skipInterface) {
2541 if (seenTypes.contains(t.tsym)) {
2542 //this is possible when an interface is implemented in multiple
2543 //superclasses, or when a classs hierarchy is circular - in such
2544 //cases we don't need to recurse (empty scope is returned)
2545 return new CompoundScope(t.tsym);
2546 }
2547 try {
2548 seenTypes = seenTypes.prepend(t.tsym);
2549 ClassSymbol csym = (ClassSymbol)t.tsym;
2550 Entry e = _map.get(csym);
2551 if (e == null || !e.matches(skipInterface)) {
2552 CompoundScope membersClosure = new CompoundScope(csym);
2553 if (!skipInterface) {
2554 for (Type i : interfaces(t)) {
2555 membersClosure.addSubScope(visit(i, skipInterface));
2556 }
2557 }
2558 membersClosure.addSubScope(visit(supertype(t), skipInterface));
2559 membersClosure.addSubScope(csym.members());
2560 e = new Entry(skipInterface, membersClosure);
2561 _map.put(csym, e);
2562 }
2563 return e.compoundScope;
2564 }
2565 finally {
2566 seenTypes = seenTypes.tail;
2567 }
2568 }
2570 @Override
2571 public CompoundScope visitTypeVar(TypeVar t, Boolean skipInterface) {
2572 return visit(t.getUpperBound(), skipInterface);
2573 }
2574 }
2576 private MembersClosureCache membersCache = new MembersClosureCache();
2578 public CompoundScope membersClosure(Type site, boolean skipInterface) {
2579 return membersCache.visit(site, skipInterface);
2580 }
2581 // </editor-fold>
2584 //where
2585 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
2586 Filter<Symbol> filter = new MethodFilter(ms, site);
2587 List<MethodSymbol> candidates = List.nil();
2588 for (Symbol s : membersClosure(site, false).getElements(filter)) {
2589 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
2590 return List.of((MethodSymbol)s);
2591 } else if (!candidates.contains(s)) {
2592 candidates = candidates.prepend((MethodSymbol)s);
2593 }
2594 }
2595 return prune(candidates, ownerComparator);
2596 }
2598 public List<MethodSymbol> prune(List<MethodSymbol> methods, Comparator<MethodSymbol> cmp) {
2599 ListBuffer<MethodSymbol> methodsMin = ListBuffer.lb();
2600 for (MethodSymbol m1 : methods) {
2601 boolean isMin_m1 = true;
2602 for (MethodSymbol m2 : methods) {
2603 if (m1 == m2) continue;
2604 if (cmp.compare(m2, m1) < 0) {
2605 isMin_m1 = false;
2606 break;
2607 }
2608 }
2609 if (isMin_m1)
2610 methodsMin.append(m1);
2611 }
2612 return methodsMin.toList();
2613 }
2615 Comparator<MethodSymbol> ownerComparator = new Comparator<MethodSymbol>() {
2616 public int compare(MethodSymbol s1, MethodSymbol s2) {
2617 return s1.owner.isSubClass(s2.owner, Types.this) ? -1 : 1;
2618 }
2619 };
2620 // where
2621 private class MethodFilter implements Filter<Symbol> {
2623 Symbol msym;
2624 Type site;
2626 MethodFilter(Symbol msym, Type site) {
2627 this.msym = msym;
2628 this.site = site;
2629 }
2631 public boolean accepts(Symbol s) {
2632 return s.kind == Kinds.MTH &&
2633 s.name == msym.name &&
2634 s.isInheritedIn(site.tsym, Types.this) &&
2635 overrideEquivalent(memberType(site, s), memberType(site, msym));
2636 }
2637 };
2638 // </editor-fold>
2640 /**
2641 * Does t have the same arguments as s? It is assumed that both
2642 * types are (possibly polymorphic) method types. Monomorphic
2643 * method types "have the same arguments", if their argument lists
2644 * are equal. Polymorphic method types "have the same arguments",
2645 * if they have the same arguments after renaming all type
2646 * variables of one to corresponding type variables in the other,
2647 * where correspondence is by position in the type parameter list.
2648 */
2649 public boolean hasSameArgs(Type t, Type s) {
2650 return hasSameArgs(t, s, true);
2651 }
2653 public boolean hasSameArgs(Type t, Type s, boolean strict) {
2654 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
2655 }
2657 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
2658 return hasSameArgs.visit(t, s);
2659 }
2660 // where
2661 private class HasSameArgs extends TypeRelation {
2663 boolean strict;
2665 public HasSameArgs(boolean strict) {
2666 this.strict = strict;
2667 }
2669 public Boolean visitType(Type t, Type s) {
2670 throw new AssertionError();
2671 }
2673 @Override
2674 public Boolean visitMethodType(MethodType t, Type s) {
2675 return s.tag == METHOD
2676 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2677 }
2679 @Override
2680 public Boolean visitForAll(ForAll t, Type s) {
2681 if (s.tag != FORALL)
2682 return strict ? false : visitMethodType(t.asMethodType(), s);
2684 ForAll forAll = (ForAll)s;
2685 return hasSameBounds(t, forAll)
2686 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2687 }
2689 @Override
2690 public Boolean visitErrorType(ErrorType t, Type s) {
2691 return false;
2692 }
2693 };
2695 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
2696 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
2698 // </editor-fold>
2700 // <editor-fold defaultstate="collapsed" desc="subst">
2701 public List<Type> subst(List<Type> ts,
2702 List<Type> from,
2703 List<Type> to) {
2704 return new Subst(from, to).subst(ts);
2705 }
2707 /**
2708 * Substitute all occurrences of a type in `from' with the
2709 * corresponding type in `to' in 't'. Match lists `from' and `to'
2710 * from the right: If lists have different length, discard leading
2711 * elements of the longer list.
2712 */
2713 public Type subst(Type t, List<Type> from, List<Type> to) {
2714 return new Subst(from, to).subst(t);
2715 }
2717 private class Subst extends UnaryVisitor<Type> {
2718 List<Type> from;
2719 List<Type> to;
2721 public Subst(List<Type> from, List<Type> to) {
2722 int fromLength = from.length();
2723 int toLength = to.length();
2724 while (fromLength > toLength) {
2725 fromLength--;
2726 from = from.tail;
2727 }
2728 while (fromLength < toLength) {
2729 toLength--;
2730 to = to.tail;
2731 }
2732 this.from = from;
2733 this.to = to;
2734 }
2736 Type subst(Type t) {
2737 if (from.tail == null)
2738 return t;
2739 else
2740 return visit(t);
2741 }
2743 List<Type> subst(List<Type> ts) {
2744 if (from.tail == null)
2745 return ts;
2746 boolean wild = false;
2747 if (ts.nonEmpty() && from.nonEmpty()) {
2748 Type head1 = subst(ts.head);
2749 List<Type> tail1 = subst(ts.tail);
2750 if (head1 != ts.head || tail1 != ts.tail)
2751 return tail1.prepend(head1);
2752 }
2753 return ts;
2754 }
2756 public Type visitType(Type t, Void ignored) {
2757 return t;
2758 }
2760 @Override
2761 public Type visitMethodType(MethodType t, Void ignored) {
2762 List<Type> argtypes = subst(t.argtypes);
2763 Type restype = subst(t.restype);
2764 List<Type> thrown = subst(t.thrown);
2765 if (argtypes == t.argtypes &&
2766 restype == t.restype &&
2767 thrown == t.thrown)
2768 return t;
2769 else
2770 return new MethodType(argtypes, restype, thrown, t.tsym);
2771 }
2773 @Override
2774 public Type visitTypeVar(TypeVar t, Void ignored) {
2775 for (List<Type> from = this.from, to = this.to;
2776 from.nonEmpty();
2777 from = from.tail, to = to.tail) {
2778 if (t == from.head) {
2779 return to.head.withTypeVar(t);
2780 }
2781 }
2782 return t;
2783 }
2785 @Override
2786 public Type visitClassType(ClassType t, Void ignored) {
2787 if (!t.isCompound()) {
2788 List<Type> typarams = t.getTypeArguments();
2789 List<Type> typarams1 = subst(typarams);
2790 Type outer = t.getEnclosingType();
2791 Type outer1 = subst(outer);
2792 if (typarams1 == typarams && outer1 == outer)
2793 return t;
2794 else
2795 return new ClassType(outer1, typarams1, t.tsym);
2796 } else {
2797 Type st = subst(supertype(t));
2798 List<Type> is = upperBounds(subst(interfaces(t)));
2799 if (st == supertype(t) && is == interfaces(t))
2800 return t;
2801 else
2802 return makeCompoundType(is.prepend(st));
2803 }
2804 }
2806 @Override
2807 public Type visitWildcardType(WildcardType t, Void ignored) {
2808 Type bound = t.type;
2809 if (t.kind != BoundKind.UNBOUND)
2810 bound = subst(bound);
2811 if (bound == t.type) {
2812 return t;
2813 } else {
2814 if (t.isExtendsBound() && bound.isExtendsBound())
2815 bound = upperBound(bound);
2816 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2817 }
2818 }
2820 @Override
2821 public Type visitArrayType(ArrayType t, Void ignored) {
2822 Type elemtype = subst(t.elemtype);
2823 if (elemtype == t.elemtype)
2824 return t;
2825 else
2826 return new ArrayType(upperBound(elemtype), t.tsym);
2827 }
2829 @Override
2830 public Type visitForAll(ForAll t, Void ignored) {
2831 if (Type.containsAny(to, t.tvars)) {
2832 //perform alpha-renaming of free-variables in 't'
2833 //if 'to' types contain variables that are free in 't'
2834 List<Type> freevars = newInstances(t.tvars);
2835 t = new ForAll(freevars,
2836 Types.this.subst(t.qtype, t.tvars, freevars));
2837 }
2838 List<Type> tvars1 = substBounds(t.tvars, from, to);
2839 Type qtype1 = subst(t.qtype);
2840 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2841 return t;
2842 } else if (tvars1 == t.tvars) {
2843 return new ForAll(tvars1, qtype1);
2844 } else {
2845 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2846 }
2847 }
2849 @Override
2850 public Type visitErrorType(ErrorType t, Void ignored) {
2851 return t;
2852 }
2853 }
2855 public List<Type> substBounds(List<Type> tvars,
2856 List<Type> from,
2857 List<Type> to) {
2858 if (tvars.isEmpty())
2859 return tvars;
2860 ListBuffer<Type> newBoundsBuf = lb();
2861 boolean changed = false;
2862 // calculate new bounds
2863 for (Type t : tvars) {
2864 TypeVar tv = (TypeVar) t;
2865 Type bound = subst(tv.bound, from, to);
2866 if (bound != tv.bound)
2867 changed = true;
2868 newBoundsBuf.append(bound);
2869 }
2870 if (!changed)
2871 return tvars;
2872 ListBuffer<Type> newTvars = lb();
2873 // create new type variables without bounds
2874 for (Type t : tvars) {
2875 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2876 }
2877 // the new bounds should use the new type variables in place
2878 // of the old
2879 List<Type> newBounds = newBoundsBuf.toList();
2880 from = tvars;
2881 to = newTvars.toList();
2882 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2883 newBounds.head = subst(newBounds.head, from, to);
2884 }
2885 newBounds = newBoundsBuf.toList();
2886 // set the bounds of new type variables to the new bounds
2887 for (Type t : newTvars.toList()) {
2888 TypeVar tv = (TypeVar) t;
2889 tv.bound = newBounds.head;
2890 newBounds = newBounds.tail;
2891 }
2892 return newTvars.toList();
2893 }
2895 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2896 Type bound1 = subst(t.bound, from, to);
2897 if (bound1 == t.bound)
2898 return t;
2899 else {
2900 // create new type variable without bounds
2901 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2902 // the new bound should use the new type variable in place
2903 // of the old
2904 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2905 return tv;
2906 }
2907 }
2908 // </editor-fold>
2910 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2911 /**
2912 * Does t have the same bounds for quantified variables as s?
2913 */
2914 boolean hasSameBounds(ForAll t, ForAll s) {
2915 List<Type> l1 = t.tvars;
2916 List<Type> l2 = s.tvars;
2917 while (l1.nonEmpty() && l2.nonEmpty() &&
2918 isSameType(l1.head.getUpperBound(),
2919 subst(l2.head.getUpperBound(),
2920 s.tvars,
2921 t.tvars))) {
2922 l1 = l1.tail;
2923 l2 = l2.tail;
2924 }
2925 return l1.isEmpty() && l2.isEmpty();
2926 }
2927 // </editor-fold>
2929 // <editor-fold defaultstate="collapsed" desc="newInstances">
2930 /** Create new vector of type variables from list of variables
2931 * changing all recursive bounds from old to new list.
2932 */
2933 public List<Type> newInstances(List<Type> tvars) {
2934 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2935 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2936 TypeVar tv = (TypeVar) l.head;
2937 tv.bound = subst(tv.bound, tvars, tvars1);
2938 }
2939 return tvars1;
2940 }
2941 private static final Mapping newInstanceFun = new Mapping("newInstanceFun") {
2942 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2943 };
2944 // </editor-fold>
2946 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
2947 return original.accept(methodWithParameters, newParams);
2948 }
2949 // where
2950 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
2951 public Type visitType(Type t, List<Type> newParams) {
2952 throw new IllegalArgumentException("Not a method type: " + t);
2953 }
2954 public Type visitMethodType(MethodType t, List<Type> newParams) {
2955 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
2956 }
2957 public Type visitForAll(ForAll t, List<Type> newParams) {
2958 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
2959 }
2960 };
2962 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
2963 return original.accept(methodWithThrown, newThrown);
2964 }
2965 // where
2966 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
2967 public Type visitType(Type t, List<Type> newThrown) {
2968 throw new IllegalArgumentException("Not a method type: " + t);
2969 }
2970 public Type visitMethodType(MethodType t, List<Type> newThrown) {
2971 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
2972 }
2973 public Type visitForAll(ForAll t, List<Type> newThrown) {
2974 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
2975 }
2976 };
2978 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
2979 return original.accept(methodWithReturn, newReturn);
2980 }
2981 // where
2982 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
2983 public Type visitType(Type t, Type newReturn) {
2984 throw new IllegalArgumentException("Not a method type: " + t);
2985 }
2986 public Type visitMethodType(MethodType t, Type newReturn) {
2987 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym);
2988 }
2989 public Type visitForAll(ForAll t, Type newReturn) {
2990 return new ForAll(t.tvars, t.qtype.accept(this, newReturn));
2991 }
2992 };
2994 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2995 public Type createErrorType(Type originalType) {
2996 return new ErrorType(originalType, syms.errSymbol);
2997 }
2999 public Type createErrorType(ClassSymbol c, Type originalType) {
3000 return new ErrorType(c, originalType);
3001 }
3003 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3004 return new ErrorType(name, container, originalType);
3005 }
3006 // </editor-fold>
3008 // <editor-fold defaultstate="collapsed" desc="rank">
3009 /**
3010 * The rank of a class is the length of the longest path between
3011 * the class and java.lang.Object in the class inheritance
3012 * graph. Undefined for all but reference types.
3013 */
3014 public int rank(Type t) {
3015 t = t.unannotatedType();
3016 switch(t.tag) {
3017 case CLASS: {
3018 ClassType cls = (ClassType)t;
3019 if (cls.rank_field < 0) {
3020 Name fullname = cls.tsym.getQualifiedName();
3021 if (fullname == names.java_lang_Object)
3022 cls.rank_field = 0;
3023 else {
3024 int r = rank(supertype(cls));
3025 for (List<Type> l = interfaces(cls);
3026 l.nonEmpty();
3027 l = l.tail) {
3028 if (rank(l.head) > r)
3029 r = rank(l.head);
3030 }
3031 cls.rank_field = r + 1;
3032 }
3033 }
3034 return cls.rank_field;
3035 }
3036 case TYPEVAR: {
3037 TypeVar tvar = (TypeVar)t;
3038 if (tvar.rank_field < 0) {
3039 int r = rank(supertype(tvar));
3040 for (List<Type> l = interfaces(tvar);
3041 l.nonEmpty();
3042 l = l.tail) {
3043 if (rank(l.head) > r) r = rank(l.head);
3044 }
3045 tvar.rank_field = r + 1;
3046 }
3047 return tvar.rank_field;
3048 }
3049 case ERROR:
3050 return 0;
3051 default:
3052 throw new AssertionError();
3053 }
3054 }
3055 // </editor-fold>
3057 /**
3058 * Helper method for generating a string representation of a given type
3059 * accordingly to a given locale
3060 */
3061 public String toString(Type t, Locale locale) {
3062 return Printer.createStandardPrinter(messages).visit(t, locale);
3063 }
3065 /**
3066 * Helper method for generating a string representation of a given type
3067 * accordingly to a given locale
3068 */
3069 public String toString(Symbol t, Locale locale) {
3070 return Printer.createStandardPrinter(messages).visit(t, locale);
3071 }
3073 // <editor-fold defaultstate="collapsed" desc="toString">
3074 /**
3075 * This toString is slightly more descriptive than the one on Type.
3076 *
3077 * @deprecated Types.toString(Type t, Locale l) provides better support
3078 * for localization
3079 */
3080 @Deprecated
3081 public String toString(Type t) {
3082 if (t.tag == FORALL) {
3083 ForAll forAll = (ForAll)t;
3084 return typaramsString(forAll.tvars) + forAll.qtype;
3085 }
3086 return "" + t;
3087 }
3088 // where
3089 private String typaramsString(List<Type> tvars) {
3090 StringBuilder s = new StringBuilder();
3091 s.append('<');
3092 boolean first = true;
3093 for (Type t : tvars) {
3094 if (!first) s.append(", ");
3095 first = false;
3096 appendTyparamString(((TypeVar)t), s);
3097 }
3098 s.append('>');
3099 return s.toString();
3100 }
3101 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3102 buf.append(t);
3103 if (t.bound == null ||
3104 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
3105 return;
3106 buf.append(" extends "); // Java syntax; no need for i18n
3107 Type bound = t.bound;
3108 if (!bound.isCompound()) {
3109 buf.append(bound);
3110 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3111 buf.append(supertype(t));
3112 for (Type intf : interfaces(t)) {
3113 buf.append('&');
3114 buf.append(intf);
3115 }
3116 } else {
3117 // No superclass was given in bounds.
3118 // In this case, supertype is Object, erasure is first interface.
3119 boolean first = true;
3120 for (Type intf : interfaces(t)) {
3121 if (!first) buf.append('&');
3122 first = false;
3123 buf.append(intf);
3124 }
3125 }
3126 }
3127 // </editor-fold>
3129 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3130 /**
3131 * A cache for closures.
3132 *
3133 * <p>A closure is a list of all the supertypes and interfaces of
3134 * a class or interface type, ordered by ClassSymbol.precedes
3135 * (that is, subclasses come first, arbitrary but fixed
3136 * otherwise).
3137 */
3138 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
3140 /**
3141 * Returns the closure of a class or interface type.
3142 */
3143 public List<Type> closure(Type t) {
3144 List<Type> cl = closureCache.get(t);
3145 if (cl == null) {
3146 Type st = supertype(t);
3147 if (!t.isCompound()) {
3148 if (st.tag == CLASS) {
3149 cl = insert(closure(st), t);
3150 } else if (st.tag == TYPEVAR) {
3151 cl = closure(st).prepend(t);
3152 } else {
3153 cl = List.of(t);
3154 }
3155 } else {
3156 cl = closure(supertype(t));
3157 }
3158 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3159 cl = union(cl, closure(l.head));
3160 closureCache.put(t, cl);
3161 }
3162 return cl;
3163 }
3165 /**
3166 * Insert a type in a closure
3167 */
3168 public List<Type> insert(List<Type> cl, Type t) {
3169 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
3170 return cl.prepend(t);
3171 } else if (cl.head.tsym.precedes(t.tsym, this)) {
3172 return insert(cl.tail, t).prepend(cl.head);
3173 } else {
3174 return cl;
3175 }
3176 }
3178 /**
3179 * Form the union of two closures
3180 */
3181 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3182 if (cl1.isEmpty()) {
3183 return cl2;
3184 } else if (cl2.isEmpty()) {
3185 return cl1;
3186 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
3187 return union(cl1.tail, cl2).prepend(cl1.head);
3188 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3189 return union(cl1, cl2.tail).prepend(cl2.head);
3190 } else {
3191 return union(cl1.tail, cl2.tail).prepend(cl1.head);
3192 }
3193 }
3195 /**
3196 * Intersect two closures
3197 */
3198 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3199 if (cl1 == cl2)
3200 return cl1;
3201 if (cl1.isEmpty() || cl2.isEmpty())
3202 return List.nil();
3203 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3204 return intersect(cl1.tail, cl2);
3205 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3206 return intersect(cl1, cl2.tail);
3207 if (isSameType(cl1.head, cl2.head))
3208 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3209 if (cl1.head.tsym == cl2.head.tsym &&
3210 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
3211 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3212 Type merge = merge(cl1.head,cl2.head);
3213 return intersect(cl1.tail, cl2.tail).prepend(merge);
3214 }
3215 if (cl1.head.isRaw() || cl2.head.isRaw())
3216 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3217 }
3218 return intersect(cl1.tail, cl2.tail);
3219 }
3220 // where
3221 class TypePair {
3222 final Type t1;
3223 final Type t2;
3224 TypePair(Type t1, Type t2) {
3225 this.t1 = t1;
3226 this.t2 = t2;
3227 }
3228 @Override
3229 public int hashCode() {
3230 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3231 }
3232 @Override
3233 public boolean equals(Object obj) {
3234 if (!(obj instanceof TypePair))
3235 return false;
3236 TypePair typePair = (TypePair)obj;
3237 return isSameType(t1, typePair.t1)
3238 && isSameType(t2, typePair.t2);
3239 }
3240 }
3241 Set<TypePair> mergeCache = new HashSet<TypePair>();
3242 private Type merge(Type c1, Type c2) {
3243 ClassType class1 = (ClassType) c1;
3244 List<Type> act1 = class1.getTypeArguments();
3245 ClassType class2 = (ClassType) c2;
3246 List<Type> act2 = class2.getTypeArguments();
3247 ListBuffer<Type> merged = new ListBuffer<Type>();
3248 List<Type> typarams = class1.tsym.type.getTypeArguments();
3250 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3251 if (containsType(act1.head, act2.head)) {
3252 merged.append(act1.head);
3253 } else if (containsType(act2.head, act1.head)) {
3254 merged.append(act2.head);
3255 } else {
3256 TypePair pair = new TypePair(c1, c2);
3257 Type m;
3258 if (mergeCache.add(pair)) {
3259 m = new WildcardType(lub(upperBound(act1.head),
3260 upperBound(act2.head)),
3261 BoundKind.EXTENDS,
3262 syms.boundClass);
3263 mergeCache.remove(pair);
3264 } else {
3265 m = new WildcardType(syms.objectType,
3266 BoundKind.UNBOUND,
3267 syms.boundClass);
3268 }
3269 merged.append(m.withTypeVar(typarams.head));
3270 }
3271 act1 = act1.tail;
3272 act2 = act2.tail;
3273 typarams = typarams.tail;
3274 }
3275 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3276 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
3277 }
3279 /**
3280 * Return the minimum type of a closure, a compound type if no
3281 * unique minimum exists.
3282 */
3283 private Type compoundMin(List<Type> cl) {
3284 if (cl.isEmpty()) return syms.objectType;
3285 List<Type> compound = closureMin(cl);
3286 if (compound.isEmpty())
3287 return null;
3288 else if (compound.tail.isEmpty())
3289 return compound.head;
3290 else
3291 return makeCompoundType(compound);
3292 }
3294 /**
3295 * Return the minimum types of a closure, suitable for computing
3296 * compoundMin or glb.
3297 */
3298 private List<Type> closureMin(List<Type> cl) {
3299 ListBuffer<Type> classes = lb();
3300 ListBuffer<Type> interfaces = lb();
3301 while (!cl.isEmpty()) {
3302 Type current = cl.head;
3303 if (current.isInterface())
3304 interfaces.append(current);
3305 else
3306 classes.append(current);
3307 ListBuffer<Type> candidates = lb();
3308 for (Type t : cl.tail) {
3309 if (!isSubtypeNoCapture(current, t))
3310 candidates.append(t);
3311 }
3312 cl = candidates.toList();
3313 }
3314 return classes.appendList(interfaces).toList();
3315 }
3317 /**
3318 * Return the least upper bound of pair of types. if the lub does
3319 * not exist return null.
3320 */
3321 public Type lub(Type t1, Type t2) {
3322 return lub(List.of(t1, t2));
3323 }
3325 /**
3326 * Return the least upper bound (lub) of set of types. If the lub
3327 * does not exist return the type of null (bottom).
3328 */
3329 public Type lub(List<Type> ts) {
3330 final int ARRAY_BOUND = 1;
3331 final int CLASS_BOUND = 2;
3332 int boundkind = 0;
3333 for (Type t : ts) {
3334 switch (t.tag) {
3335 case CLASS:
3336 boundkind |= CLASS_BOUND;
3337 break;
3338 case ARRAY:
3339 boundkind |= ARRAY_BOUND;
3340 break;
3341 case TYPEVAR:
3342 do {
3343 t = t.getUpperBound();
3344 } while (t.tag == TYPEVAR);
3345 if (t.tag == ARRAY) {
3346 boundkind |= ARRAY_BOUND;
3347 } else {
3348 boundkind |= CLASS_BOUND;
3349 }
3350 break;
3351 default:
3352 if (t.isPrimitive())
3353 return syms.errType;
3354 }
3355 }
3356 switch (boundkind) {
3357 case 0:
3358 return syms.botType;
3360 case ARRAY_BOUND:
3361 // calculate lub(A[], B[])
3362 List<Type> elements = Type.map(ts, elemTypeFun);
3363 for (Type t : elements) {
3364 if (t.isPrimitive()) {
3365 // if a primitive type is found, then return
3366 // arraySuperType unless all the types are the
3367 // same
3368 Type first = ts.head;
3369 for (Type s : ts.tail) {
3370 if (!isSameType(first, s)) {
3371 // lub(int[], B[]) is Cloneable & Serializable
3372 return arraySuperType();
3373 }
3374 }
3375 // all the array types are the same, return one
3376 // lub(int[], int[]) is int[]
3377 return first;
3378 }
3379 }
3380 // lub(A[], B[]) is lub(A, B)[]
3381 return new ArrayType(lub(elements), syms.arrayClass);
3383 case CLASS_BOUND:
3384 // calculate lub(A, B)
3385 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
3386 ts = ts.tail;
3387 Assert.check(!ts.isEmpty());
3388 //step 1 - compute erased candidate set (EC)
3389 List<Type> cl = erasedSupertypes(ts.head);
3390 for (Type t : ts.tail) {
3391 if (t.tag == CLASS || t.tag == TYPEVAR)
3392 cl = intersect(cl, erasedSupertypes(t));
3393 }
3394 //step 2 - compute minimal erased candidate set (MEC)
3395 List<Type> mec = closureMin(cl);
3396 //step 3 - for each element G in MEC, compute lci(Inv(G))
3397 List<Type> candidates = List.nil();
3398 for (Type erasedSupertype : mec) {
3399 List<Type> lci = List.of(asSuper(ts.head, erasedSupertype.tsym));
3400 for (Type t : ts) {
3401 lci = intersect(lci, List.of(asSuper(t, erasedSupertype.tsym)));
3402 }
3403 candidates = candidates.appendList(lci);
3404 }
3405 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
3406 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
3407 return compoundMin(candidates);
3409 default:
3410 // calculate lub(A, B[])
3411 List<Type> classes = List.of(arraySuperType());
3412 for (Type t : ts) {
3413 if (t.tag != ARRAY) // Filter out any arrays
3414 classes = classes.prepend(t);
3415 }
3416 // lub(A, B[]) is lub(A, arraySuperType)
3417 return lub(classes);
3418 }
3419 }
3420 // where
3421 List<Type> erasedSupertypes(Type t) {
3422 ListBuffer<Type> buf = lb();
3423 for (Type sup : closure(t)) {
3424 if (sup.tag == TYPEVAR) {
3425 buf.append(sup);
3426 } else {
3427 buf.append(erasure(sup));
3428 }
3429 }
3430 return buf.toList();
3431 }
3433 private Type arraySuperType = null;
3434 private Type arraySuperType() {
3435 // initialized lazily to avoid problems during compiler startup
3436 if (arraySuperType == null) {
3437 synchronized (this) {
3438 if (arraySuperType == null) {
3439 // JLS 10.8: all arrays implement Cloneable and Serializable.
3440 arraySuperType = makeCompoundType(List.of(syms.serializableType,
3441 syms.cloneableType), true);
3442 }
3443 }
3444 }
3445 return arraySuperType;
3446 }
3447 // </editor-fold>
3449 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
3450 public Type glb(List<Type> ts) {
3451 Type t1 = ts.head;
3452 for (Type t2 : ts.tail) {
3453 if (t1.isErroneous())
3454 return t1;
3455 t1 = glb(t1, t2);
3456 }
3457 return t1;
3458 }
3459 //where
3460 public Type glb(Type t, Type s) {
3461 if (s == null)
3462 return t;
3463 else if (t.isPrimitive() || s.isPrimitive())
3464 return syms.errType;
3465 else if (isSubtypeNoCapture(t, s))
3466 return t;
3467 else if (isSubtypeNoCapture(s, t))
3468 return s;
3470 List<Type> closure = union(closure(t), closure(s));
3471 List<Type> bounds = closureMin(closure);
3473 if (bounds.isEmpty()) { // length == 0
3474 return syms.objectType;
3475 } else if (bounds.tail.isEmpty()) { // length == 1
3476 return bounds.head;
3477 } else { // length > 1
3478 int classCount = 0;
3479 for (Type bound : bounds)
3480 if (!bound.isInterface())
3481 classCount++;
3482 if (classCount > 1)
3483 return createErrorType(t);
3484 }
3485 return makeCompoundType(bounds);
3486 }
3487 // </editor-fold>
3489 // <editor-fold defaultstate="collapsed" desc="hashCode">
3490 /**
3491 * Compute a hash code on a type.
3492 */
3493 public int hashCode(Type t) {
3494 return hashCode.visit(t);
3495 }
3496 // where
3497 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
3499 public Integer visitType(Type t, Void ignored) {
3500 return t.tag.ordinal();
3501 }
3503 @Override
3504 public Integer visitClassType(ClassType t, Void ignored) {
3505 int result = visit(t.getEnclosingType());
3506 result *= 127;
3507 result += t.tsym.flatName().hashCode();
3508 for (Type s : t.getTypeArguments()) {
3509 result *= 127;
3510 result += visit(s);
3511 }
3512 return result;
3513 }
3515 @Override
3516 public Integer visitMethodType(MethodType t, Void ignored) {
3517 int h = METHOD.ordinal();
3518 for (List<Type> thisargs = t.argtypes;
3519 thisargs.tail != null;
3520 thisargs = thisargs.tail)
3521 h = (h << 5) + visit(thisargs.head);
3522 return (h << 5) + visit(t.restype);
3523 }
3525 @Override
3526 public Integer visitWildcardType(WildcardType t, Void ignored) {
3527 int result = t.kind.hashCode();
3528 if (t.type != null) {
3529 result *= 127;
3530 result += visit(t.type);
3531 }
3532 return result;
3533 }
3535 @Override
3536 public Integer visitArrayType(ArrayType t, Void ignored) {
3537 return visit(t.elemtype) + 12;
3538 }
3540 @Override
3541 public Integer visitTypeVar(TypeVar t, Void ignored) {
3542 return System.identityHashCode(t.tsym);
3543 }
3545 @Override
3546 public Integer visitUndetVar(UndetVar t, Void ignored) {
3547 return System.identityHashCode(t);
3548 }
3550 @Override
3551 public Integer visitErrorType(ErrorType t, Void ignored) {
3552 return 0;
3553 }
3554 };
3555 // </editor-fold>
3557 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
3558 /**
3559 * Does t have a result that is a subtype of the result type of s,
3560 * suitable for covariant returns? It is assumed that both types
3561 * are (possibly polymorphic) method types. Monomorphic method
3562 * types are handled in the obvious way. Polymorphic method types
3563 * require renaming all type variables of one to corresponding
3564 * type variables in the other, where correspondence is by
3565 * position in the type parameter list. */
3566 public boolean resultSubtype(Type t, Type s, Warner warner) {
3567 List<Type> tvars = t.getTypeArguments();
3568 List<Type> svars = s.getTypeArguments();
3569 Type tres = t.getReturnType();
3570 Type sres = subst(s.getReturnType(), svars, tvars);
3571 return covariantReturnType(tres, sres, warner);
3572 }
3574 /**
3575 * Return-Type-Substitutable.
3576 * @jls section 8.4.5
3577 */
3578 public boolean returnTypeSubstitutable(Type r1, Type r2) {
3579 if (hasSameArgs(r1, r2))
3580 return resultSubtype(r1, r2, noWarnings);
3581 else
3582 return covariantReturnType(r1.getReturnType(),
3583 erasure(r2.getReturnType()),
3584 noWarnings);
3585 }
3587 public boolean returnTypeSubstitutable(Type r1,
3588 Type r2, Type r2res,
3589 Warner warner) {
3590 if (isSameType(r1.getReturnType(), r2res))
3591 return true;
3592 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
3593 return false;
3595 if (hasSameArgs(r1, r2))
3596 return covariantReturnType(r1.getReturnType(), r2res, warner);
3597 if (!allowCovariantReturns)
3598 return false;
3599 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
3600 return true;
3601 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
3602 return false;
3603 warner.warn(LintCategory.UNCHECKED);
3604 return true;
3605 }
3607 /**
3608 * Is t an appropriate return type in an overrider for a
3609 * method that returns s?
3610 */
3611 public boolean covariantReturnType(Type t, Type s, Warner warner) {
3612 return
3613 isSameType(t, s) ||
3614 allowCovariantReturns &&
3615 !t.isPrimitive() &&
3616 !s.isPrimitive() &&
3617 isAssignable(t, s, warner);
3618 }
3619 // </editor-fold>
3621 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
3622 /**
3623 * Return the class that boxes the given primitive.
3624 */
3625 public ClassSymbol boxedClass(Type t) {
3626 return reader.enterClass(syms.boxedName[t.tag.ordinal()]);
3627 }
3629 /**
3630 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
3631 */
3632 public Type boxedTypeOrType(Type t) {
3633 return t.isPrimitive() ?
3634 boxedClass(t).type :
3635 t;
3636 }
3638 /**
3639 * Return the primitive type corresponding to a boxed type.
3640 */
3641 public Type unboxedType(Type t) {
3642 if (allowBoxing) {
3643 for (int i=0; i<syms.boxedName.length; i++) {
3644 Name box = syms.boxedName[i];
3645 if (box != null &&
3646 asSuper(t, reader.enterClass(box)) != null)
3647 return syms.typeOfTag[i];
3648 }
3649 }
3650 return Type.noType;
3651 }
3653 /**
3654 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
3655 */
3656 public Type unboxedTypeOrType(Type t) {
3657 Type unboxedType = unboxedType(t);
3658 return unboxedType.tag == NONE ? t : unboxedType;
3659 }
3660 // </editor-fold>
3662 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3663 /*
3664 * JLS 5.1.10 Capture Conversion:
3665 *
3666 * Let G name a generic type declaration with n formal type
3667 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3668 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3669 * where, for 1 <= i <= n:
3670 *
3671 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3672 * Si is a fresh type variable whose upper bound is
3673 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3674 * type.
3675 *
3676 * + If Ti is a wildcard type argument of the form ? extends Bi,
3677 * then Si is a fresh type variable whose upper bound is
3678 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3679 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3680 * a compile-time error if for any two classes (not interfaces)
3681 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3682 *
3683 * + If Ti is a wildcard type argument of the form ? super Bi,
3684 * then Si is a fresh type variable whose upper bound is
3685 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3686 *
3687 * + Otherwise, Si = Ti.
3688 *
3689 * Capture conversion on any type other than a parameterized type
3690 * (4.5) acts as an identity conversion (5.1.1). Capture
3691 * conversions never require a special action at run time and
3692 * therefore never throw an exception at run time.
3693 *
3694 * Capture conversion is not applied recursively.
3695 */
3696 /**
3697 * Capture conversion as specified by the JLS.
3698 */
3700 public List<Type> capture(List<Type> ts) {
3701 List<Type> buf = List.nil();
3702 for (Type t : ts) {
3703 buf = buf.prepend(capture(t));
3704 }
3705 return buf.reverse();
3706 }
3707 public Type capture(Type t) {
3708 if (t.tag != CLASS)
3709 return t;
3710 if (t.getEnclosingType() != Type.noType) {
3711 Type capturedEncl = capture(t.getEnclosingType());
3712 if (capturedEncl != t.getEnclosingType()) {
3713 Type type1 = memberType(capturedEncl, t.tsym);
3714 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3715 }
3716 }
3717 t = t.unannotatedType();
3718 ClassType cls = (ClassType)t;
3719 if (cls.isRaw() || !cls.isParameterized())
3720 return cls;
3722 ClassType G = (ClassType)cls.asElement().asType();
3723 List<Type> A = G.getTypeArguments();
3724 List<Type> T = cls.getTypeArguments();
3725 List<Type> S = freshTypeVariables(T);
3727 List<Type> currentA = A;
3728 List<Type> currentT = T;
3729 List<Type> currentS = S;
3730 boolean captured = false;
3731 while (!currentA.isEmpty() &&
3732 !currentT.isEmpty() &&
3733 !currentS.isEmpty()) {
3734 if (currentS.head != currentT.head) {
3735 captured = true;
3736 WildcardType Ti = (WildcardType)currentT.head;
3737 Type Ui = currentA.head.getUpperBound();
3738 CapturedType Si = (CapturedType)currentS.head;
3739 if (Ui == null)
3740 Ui = syms.objectType;
3741 switch (Ti.kind) {
3742 case UNBOUND:
3743 Si.bound = subst(Ui, A, S);
3744 Si.lower = syms.botType;
3745 break;
3746 case EXTENDS:
3747 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3748 Si.lower = syms.botType;
3749 break;
3750 case SUPER:
3751 Si.bound = subst(Ui, A, S);
3752 Si.lower = Ti.getSuperBound();
3753 break;
3754 }
3755 if (Si.bound == Si.lower)
3756 currentS.head = Si.bound;
3757 }
3758 currentA = currentA.tail;
3759 currentT = currentT.tail;
3760 currentS = currentS.tail;
3761 }
3762 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3763 return erasure(t); // some "rare" type involved
3765 if (captured)
3766 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3767 else
3768 return t;
3769 }
3770 // where
3771 public List<Type> freshTypeVariables(List<Type> types) {
3772 ListBuffer<Type> result = lb();
3773 for (Type t : types) {
3774 if (t.tag == WILDCARD) {
3775 Type bound = ((WildcardType)t).getExtendsBound();
3776 if (bound == null)
3777 bound = syms.objectType;
3778 result.append(new CapturedType(capturedName,
3779 syms.noSymbol,
3780 bound,
3781 syms.botType,
3782 (WildcardType)t));
3783 } else {
3784 result.append(t);
3785 }
3786 }
3787 return result.toList();
3788 }
3789 // </editor-fold>
3791 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3792 private List<Type> upperBounds(List<Type> ss) {
3793 if (ss.isEmpty()) return ss;
3794 Type head = upperBound(ss.head);
3795 List<Type> tail = upperBounds(ss.tail);
3796 if (head != ss.head || tail != ss.tail)
3797 return tail.prepend(head);
3798 else
3799 return ss;
3800 }
3802 private boolean sideCast(Type from, Type to, Warner warn) {
3803 // We are casting from type $from$ to type $to$, which are
3804 // non-final unrelated types. This method
3805 // tries to reject a cast by transferring type parameters
3806 // from $to$ to $from$ by common superinterfaces.
3807 boolean reverse = false;
3808 Type target = to;
3809 if ((to.tsym.flags() & INTERFACE) == 0) {
3810 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3811 reverse = true;
3812 to = from;
3813 from = target;
3814 }
3815 List<Type> commonSupers = superClosure(to, erasure(from));
3816 boolean giveWarning = commonSupers.isEmpty();
3817 // The arguments to the supers could be unified here to
3818 // get a more accurate analysis
3819 while (commonSupers.nonEmpty()) {
3820 Type t1 = asSuper(from, commonSupers.head.tsym);
3821 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3822 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3823 return false;
3824 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3825 commonSupers = commonSupers.tail;
3826 }
3827 if (giveWarning && !isReifiable(reverse ? from : to))
3828 warn.warn(LintCategory.UNCHECKED);
3829 if (!allowCovariantReturns)
3830 // reject if there is a common method signature with
3831 // incompatible return types.
3832 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3833 return true;
3834 }
3836 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3837 // We are casting from type $from$ to type $to$, which are
3838 // unrelated types one of which is final and the other of
3839 // which is an interface. This method
3840 // tries to reject a cast by transferring type parameters
3841 // from the final class to the interface.
3842 boolean reverse = false;
3843 Type target = to;
3844 if ((to.tsym.flags() & INTERFACE) == 0) {
3845 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3846 reverse = true;
3847 to = from;
3848 from = target;
3849 }
3850 Assert.check((from.tsym.flags() & FINAL) != 0);
3851 Type t1 = asSuper(from, to.tsym);
3852 if (t1 == null) return false;
3853 Type t2 = to;
3854 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3855 return false;
3856 if (!allowCovariantReturns)
3857 // reject if there is a common method signature with
3858 // incompatible return types.
3859 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3860 if (!isReifiable(target) &&
3861 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3862 warn.warn(LintCategory.UNCHECKED);
3863 return true;
3864 }
3866 private boolean giveWarning(Type from, Type to) {
3867 Type subFrom = asSub(from, to.tsym);
3868 return to.isParameterized() &&
3869 (!(isUnbounded(to) ||
3870 isSubtype(from, to) ||
3871 ((subFrom != null) && containsType(to.allparams(), subFrom.allparams()))));
3872 }
3874 private List<Type> superClosure(Type t, Type s) {
3875 List<Type> cl = List.nil();
3876 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3877 if (isSubtype(s, erasure(l.head))) {
3878 cl = insert(cl, l.head);
3879 } else {
3880 cl = union(cl, superClosure(l.head, s));
3881 }
3882 }
3883 return cl;
3884 }
3886 private boolean containsTypeEquivalent(Type t, Type s) {
3887 return
3888 isSameType(t, s) || // shortcut
3889 containsType(t, s) && containsType(s, t);
3890 }
3892 // <editor-fold defaultstate="collapsed" desc="adapt">
3893 /**
3894 * Adapt a type by computing a substitution which maps a source
3895 * type to a target type.
3896 *
3897 * @param source the source type
3898 * @param target the target type
3899 * @param from the type variables of the computed substitution
3900 * @param to the types of the computed substitution.
3901 */
3902 public void adapt(Type source,
3903 Type target,
3904 ListBuffer<Type> from,
3905 ListBuffer<Type> to) throws AdaptFailure {
3906 new Adapter(from, to).adapt(source, target);
3907 }
3909 class Adapter extends SimpleVisitor<Void, Type> {
3911 ListBuffer<Type> from;
3912 ListBuffer<Type> to;
3913 Map<Symbol,Type> mapping;
3915 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3916 this.from = from;
3917 this.to = to;
3918 mapping = new HashMap<Symbol,Type>();
3919 }
3921 public void adapt(Type source, Type target) throws AdaptFailure {
3922 visit(source, target);
3923 List<Type> fromList = from.toList();
3924 List<Type> toList = to.toList();
3925 while (!fromList.isEmpty()) {
3926 Type val = mapping.get(fromList.head.tsym);
3927 if (toList.head != val)
3928 toList.head = val;
3929 fromList = fromList.tail;
3930 toList = toList.tail;
3931 }
3932 }
3934 @Override
3935 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3936 if (target.tag == CLASS)
3937 adaptRecursive(source.allparams(), target.allparams());
3938 return null;
3939 }
3941 @Override
3942 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3943 if (target.tag == ARRAY)
3944 adaptRecursive(elemtype(source), elemtype(target));
3945 return null;
3946 }
3948 @Override
3949 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3950 if (source.isExtendsBound())
3951 adaptRecursive(upperBound(source), upperBound(target));
3952 else if (source.isSuperBound())
3953 adaptRecursive(lowerBound(source), lowerBound(target));
3954 return null;
3955 }
3957 @Override
3958 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3959 // Check to see if there is
3960 // already a mapping for $source$, in which case
3961 // the old mapping will be merged with the new
3962 Type val = mapping.get(source.tsym);
3963 if (val != null) {
3964 if (val.isSuperBound() && target.isSuperBound()) {
3965 val = isSubtype(lowerBound(val), lowerBound(target))
3966 ? target : val;
3967 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3968 val = isSubtype(upperBound(val), upperBound(target))
3969 ? val : target;
3970 } else if (!isSameType(val, target)) {
3971 throw new AdaptFailure();
3972 }
3973 } else {
3974 val = target;
3975 from.append(source);
3976 to.append(target);
3977 }
3978 mapping.put(source.tsym, val);
3979 return null;
3980 }
3982 @Override
3983 public Void visitType(Type source, Type target) {
3984 return null;
3985 }
3987 private Set<TypePair> cache = new HashSet<TypePair>();
3989 private void adaptRecursive(Type source, Type target) {
3990 TypePair pair = new TypePair(source, target);
3991 if (cache.add(pair)) {
3992 try {
3993 visit(source, target);
3994 } finally {
3995 cache.remove(pair);
3996 }
3997 }
3998 }
4000 private void adaptRecursive(List<Type> source, List<Type> target) {
4001 if (source.length() == target.length()) {
4002 while (source.nonEmpty()) {
4003 adaptRecursive(source.head, target.head);
4004 source = source.tail;
4005 target = target.tail;
4006 }
4007 }
4008 }
4009 }
4011 public static class AdaptFailure extends RuntimeException {
4012 static final long serialVersionUID = -7490231548272701566L;
4013 }
4015 private void adaptSelf(Type t,
4016 ListBuffer<Type> from,
4017 ListBuffer<Type> to) {
4018 try {
4019 //if (t.tsym.type != t)
4020 adapt(t.tsym.type, t, from, to);
4021 } catch (AdaptFailure ex) {
4022 // Adapt should never fail calculating a mapping from
4023 // t.tsym.type to t as there can be no merge problem.
4024 throw new AssertionError(ex);
4025 }
4026 }
4027 // </editor-fold>
4029 /**
4030 * Rewrite all type variables (universal quantifiers) in the given
4031 * type to wildcards (existential quantifiers). This is used to
4032 * determine if a cast is allowed. For example, if high is true
4033 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4034 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4035 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4036 * List<Integer>} with a warning.
4037 * @param t a type
4038 * @param high if true return an upper bound; otherwise a lower
4039 * bound
4040 * @param rewriteTypeVars only rewrite captured wildcards if false;
4041 * otherwise rewrite all type variables
4042 * @return the type rewritten with wildcards (existential
4043 * quantifiers) only
4044 */
4045 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4046 return new Rewriter(high, rewriteTypeVars).visit(t);
4047 }
4049 class Rewriter extends UnaryVisitor<Type> {
4051 boolean high;
4052 boolean rewriteTypeVars;
4054 Rewriter(boolean high, boolean rewriteTypeVars) {
4055 this.high = high;
4056 this.rewriteTypeVars = rewriteTypeVars;
4057 }
4059 @Override
4060 public Type visitClassType(ClassType t, Void s) {
4061 ListBuffer<Type> rewritten = new ListBuffer<Type>();
4062 boolean changed = false;
4063 for (Type arg : t.allparams()) {
4064 Type bound = visit(arg);
4065 if (arg != bound) {
4066 changed = true;
4067 }
4068 rewritten.append(bound);
4069 }
4070 if (changed)
4071 return subst(t.tsym.type,
4072 t.tsym.type.allparams(),
4073 rewritten.toList());
4074 else
4075 return t;
4076 }
4078 public Type visitType(Type t, Void s) {
4079 return high ? upperBound(t) : lowerBound(t);
4080 }
4082 @Override
4083 public Type visitCapturedType(CapturedType t, Void s) {
4084 Type w_bound = t.wildcard.type;
4085 Type bound = w_bound.contains(t) ?
4086 erasure(w_bound) :
4087 visit(w_bound);
4088 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4089 }
4091 @Override
4092 public Type visitTypeVar(TypeVar t, Void s) {
4093 if (rewriteTypeVars) {
4094 Type bound = t.bound.contains(t) ?
4095 erasure(t.bound) :
4096 visit(t.bound);
4097 return rewriteAsWildcardType(bound, t, EXTENDS);
4098 } else {
4099 return t;
4100 }
4101 }
4103 @Override
4104 public Type visitWildcardType(WildcardType t, Void s) {
4105 Type bound2 = visit(t.type);
4106 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4107 }
4109 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4110 switch (bk) {
4111 case EXTENDS: return high ?
4112 makeExtendsWildcard(B(bound), formal) :
4113 makeExtendsWildcard(syms.objectType, formal);
4114 case SUPER: return high ?
4115 makeSuperWildcard(syms.botType, formal) :
4116 makeSuperWildcard(B(bound), formal);
4117 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4118 default:
4119 Assert.error("Invalid bound kind " + bk);
4120 return null;
4121 }
4122 }
4124 Type B(Type t) {
4125 while (t.tag == WILDCARD) {
4126 WildcardType w = (WildcardType)t;
4127 t = high ?
4128 w.getExtendsBound() :
4129 w.getSuperBound();
4130 if (t == null) {
4131 t = high ? syms.objectType : syms.botType;
4132 }
4133 }
4134 return t;
4135 }
4136 }
4139 /**
4140 * Create a wildcard with the given upper (extends) bound; create
4141 * an unbounded wildcard if bound is Object.
4142 *
4143 * @param bound the upper bound
4144 * @param formal the formal type parameter that will be
4145 * substituted by the wildcard
4146 */
4147 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4148 if (bound == syms.objectType) {
4149 return new WildcardType(syms.objectType,
4150 BoundKind.UNBOUND,
4151 syms.boundClass,
4152 formal);
4153 } else {
4154 return new WildcardType(bound,
4155 BoundKind.EXTENDS,
4156 syms.boundClass,
4157 formal);
4158 }
4159 }
4161 /**
4162 * Create a wildcard with the given lower (super) bound; create an
4163 * unbounded wildcard if bound is bottom (type of {@code null}).
4164 *
4165 * @param bound the lower bound
4166 * @param formal the formal type parameter that will be
4167 * substituted by the wildcard
4168 */
4169 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4170 if (bound.tag == BOT) {
4171 return new WildcardType(syms.objectType,
4172 BoundKind.UNBOUND,
4173 syms.boundClass,
4174 formal);
4175 } else {
4176 return new WildcardType(bound,
4177 BoundKind.SUPER,
4178 syms.boundClass,
4179 formal);
4180 }
4181 }
4183 /**
4184 * A wrapper for a type that allows use in sets.
4185 */
4186 public static class UniqueType {
4187 public final Type type;
4188 final Types types;
4190 public UniqueType(Type type, Types types) {
4191 this.type = type;
4192 this.types = types;
4193 }
4195 public int hashCode() {
4196 return types.hashCode(type);
4197 }
4199 public boolean equals(Object obj) {
4200 return (obj instanceof UniqueType) &&
4201 types.isSameType(type, ((UniqueType)obj).type);
4202 }
4204 public String toString() {
4205 return type.toString();
4206 }
4208 }
4209 // </editor-fold>
4211 // <editor-fold defaultstate="collapsed" desc="Visitors">
4212 /**
4213 * A default visitor for types. All visitor methods except
4214 * visitType are implemented by delegating to visitType. Concrete
4215 * subclasses must provide an implementation of visitType and can
4216 * override other methods as needed.
4217 *
4218 * @param <R> the return type of the operation implemented by this
4219 * visitor; use Void if no return type is needed.
4220 * @param <S> the type of the second argument (the first being the
4221 * type itself) of the operation implemented by this visitor; use
4222 * Void if a second argument is not needed.
4223 */
4224 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4225 final public R visit(Type t, S s) { return t.accept(this, s); }
4226 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4227 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4228 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4229 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4230 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4231 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4232 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4233 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4234 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4235 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4236 // Pretend annotations don't exist
4237 public R visitAnnotatedType(AnnotatedType t, S s) { return visit(t.underlyingType, s); }
4238 }
4240 /**
4241 * A default visitor for symbols. All visitor methods except
4242 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4243 * subclasses must provide an implementation of visitSymbol and can
4244 * override other methods as needed.
4245 *
4246 * @param <R> the return type of the operation implemented by this
4247 * visitor; use Void if no return type is needed.
4248 * @param <S> the type of the second argument (the first being the
4249 * symbol itself) of the operation implemented by this visitor; use
4250 * Void if a second argument is not needed.
4251 */
4252 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4253 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
4254 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4255 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4256 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4257 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4258 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4259 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4260 }
4262 /**
4263 * A <em>simple</em> visitor for types. This visitor is simple as
4264 * captured wildcards, for-all types (generic methods), and
4265 * undetermined type variables (part of inference) are hidden.
4266 * Captured wildcards are hidden by treating them as type
4267 * variables and the rest are hidden by visiting their qtypes.
4268 *
4269 * @param <R> the return type of the operation implemented by this
4270 * visitor; use Void if no return type is needed.
4271 * @param <S> the type of the second argument (the first being the
4272 * type itself) of the operation implemented by this visitor; use
4273 * Void if a second argument is not needed.
4274 */
4275 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4276 @Override
4277 public R visitCapturedType(CapturedType t, S s) {
4278 return visitTypeVar(t, s);
4279 }
4280 @Override
4281 public R visitForAll(ForAll t, S s) {
4282 return visit(t.qtype, s);
4283 }
4284 @Override
4285 public R visitUndetVar(UndetVar t, S s) {
4286 return visit(t.qtype, s);
4287 }
4288 }
4290 /**
4291 * A plain relation on types. That is a 2-ary function on the
4292 * form Type × Type → Boolean.
4293 * <!-- In plain text: Type x Type -> Boolean -->
4294 */
4295 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4297 /**
4298 * A convenience visitor for implementing operations that only
4299 * require one argument (the type itself), that is, unary
4300 * operations.
4301 *
4302 * @param <R> the return type of the operation implemented by this
4303 * visitor; use Void if no return type is needed.
4304 */
4305 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4306 final public R visit(Type t) { return t.accept(this, null); }
4307 }
4309 /**
4310 * A visitor for implementing a mapping from types to types. The
4311 * default behavior of this class is to implement the identity
4312 * mapping (mapping a type to itself). This can be overridden in
4313 * subclasses.
4314 *
4315 * @param <S> the type of the second argument (the first being the
4316 * type itself) of this mapping; use Void if a second argument is
4317 * not needed.
4318 */
4319 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4320 final public Type visit(Type t) { return t.accept(this, null); }
4321 public Type visitType(Type t, S s) { return t; }
4322 }
4323 // </editor-fold>
4326 // <editor-fold defaultstate="collapsed" desc="Annotation support">
4328 public RetentionPolicy getRetention(Attribute.Compound a) {
4329 return getRetention(a.type.tsym);
4330 }
4332 public RetentionPolicy getRetention(Symbol sym) {
4333 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
4334 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
4335 if (c != null) {
4336 Attribute value = c.member(names.value);
4337 if (value != null && value instanceof Attribute.Enum) {
4338 Name levelName = ((Attribute.Enum)value).value.name;
4339 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
4340 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
4341 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
4342 else ;// /* fail soft */ throw new AssertionError(levelName);
4343 }
4344 }
4345 return vis;
4346 }
4347 // </editor-fold>
4348 }
