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src/share/classes/com/sun/tools/javac/code/Types.java@94e67bed460d
src/share/classes/com/sun/tools/javac/code/Types.java
Fri, 22 Feb 2013 18:19:51 +0000
- author
- mcimadamore
- date
- Fri, 22 Feb 2013 18:19:51 +0000
- changeset 1605
- 94e67bed460d
- parent 1600
- 3fef0cae83b3
- child 1644
- 40adaf938847
- permissions
- -rw-r--r--
8008708: Regression: separate compilation causes crash in wildcards inference logic
Summary: Invalid use of WildcardType.bound in Types.removeWildcards
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.jvm.ClassFile.externalize;
52 import static com.sun.tools.javac.util.ListBuffer.lb;
54 /**
55 * Utility class containing various operations on types.
56 *
57 * <p>Unless other names are more illustrative, the following naming
58 * conventions should be observed in this file:
59 *
60 * <dl>
61 * <dt>t</dt>
62 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
63 * <dt>s</dt>
64 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
65 * <dt>ts</dt>
66 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
67 * <dt>ss</dt>
68 * <dd>A second list of types should be named ss.</dd>
69 * </dl>
70 *
71 * <p><b>This is NOT part of any supported API.
72 * If you write code that depends on this, you do so at your own risk.
73 * This code and its internal interfaces are subject to change or
74 * deletion without notice.</b>
75 */
76 public class Types {
77 protected static final Context.Key<Types> typesKey =
78 new Context.Key<Types>();
80 final Symtab syms;
81 final JavacMessages messages;
82 final Names names;
83 final boolean allowBoxing;
84 final boolean allowCovariantReturns;
85 final boolean allowObjectToPrimitiveCast;
86 final boolean allowDefaultMethods;
87 final ClassReader reader;
88 final Check chk;
89 JCDiagnostic.Factory diags;
90 List<Warner> warnStack = List.nil();
91 final Name capturedName;
92 private final FunctionDescriptorLookupError functionDescriptorLookupError;
94 public final Warner noWarnings;
96 // <editor-fold defaultstate="collapsed" desc="Instantiating">
97 public static Types instance(Context context) {
98 Types instance = context.get(typesKey);
99 if (instance == null)
100 instance = new Types(context);
101 return instance;
102 }
104 protected Types(Context context) {
105 context.put(typesKey, this);
106 syms = Symtab.instance(context);
107 names = Names.instance(context);
108 Source source = Source.instance(context);
109 allowBoxing = source.allowBoxing();
110 allowCovariantReturns = source.allowCovariantReturns();
111 allowObjectToPrimitiveCast = source.allowObjectToPrimitiveCast();
112 allowDefaultMethods = source.allowDefaultMethods();
113 reader = ClassReader.instance(context);
114 chk = Check.instance(context);
115 capturedName = names.fromString("<captured wildcard>");
116 messages = JavacMessages.instance(context);
117 diags = JCDiagnostic.Factory.instance(context);
118 functionDescriptorLookupError = new FunctionDescriptorLookupError();
119 noWarnings = new Warner(null);
120 }
121 // </editor-fold>
123 // <editor-fold defaultstate="collapsed" desc="upperBound">
124 /**
125 * The "rvalue conversion".<br>
126 * The upper bound of most types is the type
127 * itself. Wildcards, on the other hand have upper
128 * and lower bounds.
129 * @param t a type
130 * @return the upper bound of the given type
131 */
132 public Type upperBound(Type t) {
133 return upperBound.visit(t);
134 }
135 // where
136 private final MapVisitor<Void> upperBound = new MapVisitor<Void>() {
138 @Override
139 public Type visitWildcardType(WildcardType t, Void ignored) {
140 if (t.isSuperBound())
141 return t.bound == null ? syms.objectType : t.bound.bound;
142 else
143 return visit(t.type);
144 }
146 @Override
147 public Type visitCapturedType(CapturedType t, Void ignored) {
148 return visit(t.bound);
149 }
150 };
151 // </editor-fold>
153 // <editor-fold defaultstate="collapsed" desc="lowerBound">
154 /**
155 * The "lvalue conversion".<br>
156 * The lower bound of most types is the type
157 * itself. Wildcards, on the other hand have upper
158 * and lower bounds.
159 * @param t a type
160 * @return the lower bound of the given type
161 */
162 public Type lowerBound(Type t) {
163 return lowerBound.visit(t);
164 }
165 // where
166 private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() {
168 @Override
169 public Type visitWildcardType(WildcardType t, Void ignored) {
170 return t.isExtendsBound() ? syms.botType : visit(t.type);
171 }
173 @Override
174 public Type visitCapturedType(CapturedType t, Void ignored) {
175 return visit(t.getLowerBound());
176 }
177 };
178 // </editor-fold>
180 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
181 /**
182 * Checks that all the arguments to a class are unbounded
183 * wildcards or something else that doesn't make any restrictions
184 * on the arguments. If a class isUnbounded, a raw super- or
185 * subclass can be cast to it without a warning.
186 * @param t a type
187 * @return true iff the given type is unbounded or raw
188 */
189 public boolean isUnbounded(Type t) {
190 return isUnbounded.visit(t);
191 }
192 // where
193 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
195 public Boolean visitType(Type t, Void ignored) {
196 return true;
197 }
199 @Override
200 public Boolean visitClassType(ClassType t, Void ignored) {
201 List<Type> parms = t.tsym.type.allparams();
202 List<Type> args = t.allparams();
203 while (parms.nonEmpty()) {
204 WildcardType unb = new WildcardType(syms.objectType,
205 BoundKind.UNBOUND,
206 syms.boundClass,
207 (TypeVar)parms.head);
208 if (!containsType(args.head, unb))
209 return false;
210 parms = parms.tail;
211 args = args.tail;
212 }
213 return true;
214 }
215 };
216 // </editor-fold>
218 // <editor-fold defaultstate="collapsed" desc="asSub">
219 /**
220 * Return the least specific subtype of t that starts with symbol
221 * sym. If none exists, return null. The least specific subtype
222 * is determined as follows:
223 *
224 * <p>If there is exactly one parameterized instance of sym that is a
225 * subtype of t, that parameterized instance is returned.<br>
226 * Otherwise, if the plain type or raw type `sym' is a subtype of
227 * type t, the type `sym' itself is returned. Otherwise, null is
228 * returned.
229 */
230 public Type asSub(Type t, Symbol sym) {
231 return asSub.visit(t, sym);
232 }
233 // where
234 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
236 public Type visitType(Type t, Symbol sym) {
237 return null;
238 }
240 @Override
241 public Type visitClassType(ClassType t, Symbol sym) {
242 if (t.tsym == sym)
243 return t;
244 Type base = asSuper(sym.type, t.tsym);
245 if (base == null)
246 return null;
247 ListBuffer<Type> from = new ListBuffer<Type>();
248 ListBuffer<Type> to = new ListBuffer<Type>();
249 try {
250 adapt(base, t, from, to);
251 } catch (AdaptFailure ex) {
252 return null;
253 }
254 Type res = subst(sym.type, from.toList(), to.toList());
255 if (!isSubtype(res, t))
256 return null;
257 ListBuffer<Type> openVars = new ListBuffer<Type>();
258 for (List<Type> l = sym.type.allparams();
259 l.nonEmpty(); l = l.tail)
260 if (res.contains(l.head) && !t.contains(l.head))
261 openVars.append(l.head);
262 if (openVars.nonEmpty()) {
263 if (t.isRaw()) {
264 // The subtype of a raw type is raw
265 res = erasure(res);
266 } else {
267 // Unbound type arguments default to ?
268 List<Type> opens = openVars.toList();
269 ListBuffer<Type> qs = new ListBuffer<Type>();
270 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
271 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head));
272 }
273 res = subst(res, opens, qs.toList());
274 }
275 }
276 return res;
277 }
279 @Override
280 public Type visitErrorType(ErrorType t, Symbol sym) {
281 return t;
282 }
283 };
284 // </editor-fold>
286 // <editor-fold defaultstate="collapsed" desc="isConvertible">
287 /**
288 * Is t a subtype of or convertible via boxing/unboxing
289 * conversion to s?
290 */
291 public boolean isConvertible(Type t, Type s, Warner warn) {
292 if (t.tag == ERROR)
293 return true;
294 boolean tPrimitive = t.isPrimitive();
295 boolean sPrimitive = s.isPrimitive();
296 if (tPrimitive == sPrimitive) {
297 return isSubtypeUnchecked(t, s, warn);
298 }
299 if (!allowBoxing) return false;
300 return tPrimitive
301 ? isSubtype(boxedClass(t).type, s)
302 : isSubtype(unboxedType(t), s);
303 }
305 /**
306 * Is t a subtype of or convertiable via boxing/unboxing
307 * convertions to s?
308 */
309 public boolean isConvertible(Type t, Type s) {
310 return isConvertible(t, s, noWarnings);
311 }
312 // </editor-fold>
314 // <editor-fold defaultstate="collapsed" desc="findSam">
316 /**
317 * Exception used to report a function descriptor lookup failure. The exception
318 * wraps a diagnostic that can be used to generate more details error
319 * messages.
320 */
321 public static class FunctionDescriptorLookupError extends RuntimeException {
322 private static final long serialVersionUID = 0;
324 JCDiagnostic diagnostic;
326 FunctionDescriptorLookupError() {
327 this.diagnostic = null;
328 }
330 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
331 this.diagnostic = diag;
332 return this;
333 }
335 public JCDiagnostic getDiagnostic() {
336 return diagnostic;
337 }
338 }
340 /**
341 * A cache that keeps track of function descriptors associated with given
342 * functional interfaces.
343 */
344 class DescriptorCache {
346 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<TypeSymbol, Entry>();
348 class FunctionDescriptor {
349 Symbol descSym;
351 FunctionDescriptor(Symbol descSym) {
352 this.descSym = descSym;
353 }
355 public Symbol getSymbol() {
356 return descSym;
357 }
359 public Type getType(Type site) {
360 site = removeWildcards(site);
361 if (!chk.checkValidGenericType(site)) {
362 //if the inferred functional interface type is not well-formed,
363 //or if it's not a subtype of the original target, issue an error
364 throw failure(diags.fragment("no.suitable.functional.intf.inst", site));
365 }
366 return memberType(site, descSym);
367 }
368 }
370 class Entry {
371 final FunctionDescriptor cachedDescRes;
372 final int prevMark;
374 public Entry(FunctionDescriptor cachedDescRes,
375 int prevMark) {
376 this.cachedDescRes = cachedDescRes;
377 this.prevMark = prevMark;
378 }
380 boolean matches(int mark) {
381 return this.prevMark == mark;
382 }
383 }
385 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
386 Entry e = _map.get(origin);
387 CompoundScope members = membersClosure(origin.type, false);
388 if (e == null ||
389 !e.matches(members.getMark())) {
390 FunctionDescriptor descRes = findDescriptorInternal(origin, members);
391 _map.put(origin, new Entry(descRes, members.getMark()));
392 return descRes;
393 }
394 else {
395 return e.cachedDescRes;
396 }
397 }
399 /**
400 * Compute the function descriptor associated with a given functional interface
401 */
402 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin, CompoundScope membersCache) throws FunctionDescriptorLookupError {
403 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0) {
404 //t must be an interface
405 throw failure("not.a.functional.intf", origin);
406 }
408 final ListBuffer<Symbol> abstracts = ListBuffer.lb();
409 for (Symbol sym : membersCache.getElements(new DescriptorFilter(origin))) {
410 Type mtype = memberType(origin.type, sym);
411 if (abstracts.isEmpty() ||
412 (sym.name == abstracts.first().name &&
413 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
414 abstracts.append(sym);
415 } else {
416 //the target method(s) should be the only abstract members of t
417 throw failure("not.a.functional.intf.1", origin,
418 diags.fragment("incompatible.abstracts", Kinds.kindName(origin), origin));
419 }
420 }
421 if (abstracts.isEmpty()) {
422 //t must define a suitable non-generic method
423 throw failure("not.a.functional.intf.1", origin,
424 diags.fragment("no.abstracts", Kinds.kindName(origin), origin));
425 } else if (abstracts.size() == 1) {
426 return new FunctionDescriptor(abstracts.first());
427 } else { // size > 1
428 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
429 if (descRes == null) {
430 //we can get here if the functional interface is ill-formed
431 ListBuffer<JCDiagnostic> descriptors = ListBuffer.lb();
432 for (Symbol desc : abstracts) {
433 String key = desc.type.getThrownTypes().nonEmpty() ?
434 "descriptor.throws" : "descriptor";
435 descriptors.append(diags.fragment(key, desc.name,
436 desc.type.getParameterTypes(),
437 desc.type.getReturnType(),
438 desc.type.getThrownTypes()));
439 }
440 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
441 new JCDiagnostic.MultilineDiagnostic(diags.fragment("incompatible.descs.in.functional.intf",
442 Kinds.kindName(origin), origin), descriptors.toList());
443 throw failure(incompatibleDescriptors);
444 }
445 return descRes;
446 }
447 }
449 /**
450 * Compute a synthetic type for the target descriptor given a list
451 * of override-equivalent methods in the functional interface type.
452 * The resulting method type is a method type that is override-equivalent
453 * and return-type substitutable with each method in the original list.
454 */
455 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
456 //pick argument types - simply take the signature that is a
457 //subsignature of all other signatures in the list (as per JLS 8.4.2)
458 List<Symbol> mostSpecific = List.nil();
459 outer: for (Symbol msym1 : methodSyms) {
460 Type mt1 = memberType(origin.type, msym1);
461 for (Symbol msym2 : methodSyms) {
462 Type mt2 = memberType(origin.type, msym2);
463 if (!isSubSignature(mt1, mt2)) {
464 continue outer;
465 }
466 }
467 mostSpecific = mostSpecific.prepend(msym1);
468 }
469 if (mostSpecific.isEmpty()) {
470 return null;
471 }
474 //pick return types - this is done in two phases: (i) first, the most
475 //specific return type is chosen using strict subtyping; if this fails,
476 //a second attempt is made using return type substitutability (see JLS 8.4.5)
477 boolean phase2 = false;
478 Symbol bestSoFar = null;
479 while (bestSoFar == null) {
480 outer: for (Symbol msym1 : mostSpecific) {
481 Type mt1 = memberType(origin.type, msym1);
482 for (Symbol msym2 : methodSyms) {
483 Type mt2 = memberType(origin.type, msym2);
484 if (phase2 ?
485 !returnTypeSubstitutable(mt1, mt2) :
486 !isSubtypeInternal(mt1.getReturnType(), mt2.getReturnType())) {
487 continue outer;
488 }
489 }
490 bestSoFar = msym1;
491 }
492 if (phase2) {
493 break;
494 } else {
495 phase2 = true;
496 }
497 }
498 if (bestSoFar == null) return null;
500 //merge thrown types - form the intersection of all the thrown types in
501 //all the signatures in the list
502 List<Type> thrown = null;
503 for (Symbol msym1 : methodSyms) {
504 Type mt1 = memberType(origin.type, msym1);
505 thrown = (thrown == null) ?
506 mt1.getThrownTypes() :
507 chk.intersect(mt1.getThrownTypes(), thrown);
508 }
510 final List<Type> thrown1 = thrown;
511 return new FunctionDescriptor(bestSoFar) {
512 @Override
513 public Type getType(Type origin) {
514 Type mt = memberType(origin, getSymbol());
515 return createMethodTypeWithThrown(mt, thrown1);
516 }
517 };
518 }
520 boolean isSubtypeInternal(Type s, Type t) {
521 return (s.isPrimitive() && t.isPrimitive()) ?
522 isSameType(t, s) :
523 isSubtype(s, t);
524 }
526 FunctionDescriptorLookupError failure(String msg, Object... args) {
527 return failure(diags.fragment(msg, args));
528 }
530 FunctionDescriptorLookupError failure(JCDiagnostic diag) {
531 return functionDescriptorLookupError.setMessage(diag);
532 }
533 }
535 private DescriptorCache descCache = new DescriptorCache();
537 /**
538 * Find the method descriptor associated to this class symbol - if the
539 * symbol 'origin' is not a functional interface, an exception is thrown.
540 */
541 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
542 return descCache.get(origin).getSymbol();
543 }
545 /**
546 * Find the type of the method descriptor associated to this class symbol -
547 * if the symbol 'origin' is not a functional interface, an exception is thrown.
548 */
549 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
550 return descCache.get(origin.tsym).getType(origin);
551 }
553 /**
554 * Is given type a functional interface?
555 */
556 public boolean isFunctionalInterface(TypeSymbol tsym) {
557 try {
558 findDescriptorSymbol(tsym);
559 return true;
560 } catch (FunctionDescriptorLookupError ex) {
561 return false;
562 }
563 }
565 public boolean isFunctionalInterface(Type site) {
566 try {
567 findDescriptorType(site);
568 return true;
569 } catch (FunctionDescriptorLookupError ex) {
570 return false;
571 }
572 }
574 public Type removeWildcards(Type site) {
575 Type capturedSite = capture(site);
576 if (capturedSite != site) {
577 Type formalInterface = site.tsym.type;
578 ListBuffer<Type> typeargs = ListBuffer.lb();
579 List<Type> actualTypeargs = site.getTypeArguments();
580 List<Type> capturedTypeargs = capturedSite.getTypeArguments();
581 //simply replace the wildcards with its bound
582 for (Type t : formalInterface.getTypeArguments()) {
583 if (actualTypeargs.head.hasTag(WILDCARD)) {
584 WildcardType wt = (WildcardType)actualTypeargs.head;
585 Type bound;
586 switch (wt.kind) {
587 case EXTENDS:
588 case UNBOUND:
589 CapturedType capVar = (CapturedType)capturedTypeargs.head;
590 //use declared bound if it doesn't depend on formal type-args
591 bound = capVar.bound.containsAny(capturedSite.getTypeArguments()) ?
592 syms.objectType : capVar.bound;
593 break;
594 default:
595 bound = wt.type;
596 }
597 typeargs.append(bound);
598 } else {
599 typeargs.append(actualTypeargs.head);
600 }
601 actualTypeargs = actualTypeargs.tail;
602 capturedTypeargs = capturedTypeargs.tail;
603 }
604 return subst(formalInterface, formalInterface.getTypeArguments(), typeargs.toList());
605 } else {
606 return site;
607 }
608 }
609 // </editor-fold>
611 /**
612 * Scope filter used to skip methods that should be ignored (such as methods
613 * overridden by j.l.Object) during function interface conversion/marker interface checks
614 */
615 class DescriptorFilter implements Filter<Symbol> {
617 TypeSymbol origin;
619 DescriptorFilter(TypeSymbol origin) {
620 this.origin = origin;
621 }
623 @Override
624 public boolean accepts(Symbol sym) {
625 return sym.kind == Kinds.MTH &&
626 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
627 !overridesObjectMethod(origin, sym) &&
628 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
629 }
630 };
632 // <editor-fold defaultstate="collapsed" desc="isMarker">
634 /**
635 * A cache that keeps track of marker interfaces
636 */
637 class MarkerCache {
639 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<TypeSymbol, Entry>();
641 class Entry {
642 final boolean isMarkerIntf;
643 final int prevMark;
645 public Entry(boolean isMarkerIntf,
646 int prevMark) {
647 this.isMarkerIntf = isMarkerIntf;
648 this.prevMark = prevMark;
649 }
651 boolean matches(int mark) {
652 return this.prevMark == mark;
653 }
654 }
656 boolean get(TypeSymbol origin) throws FunctionDescriptorLookupError {
657 Entry e = _map.get(origin);
658 CompoundScope members = membersClosure(origin.type, false);
659 if (e == null ||
660 !e.matches(members.getMark())) {
661 boolean isMarkerIntf = isMarkerInterfaceInternal(origin, members);
662 _map.put(origin, new Entry(isMarkerIntf, members.getMark()));
663 return isMarkerIntf;
664 }
665 else {
666 return e.isMarkerIntf;
667 }
668 }
670 /**
671 * Is given symbol a marker interface
672 */
673 public boolean isMarkerInterfaceInternal(TypeSymbol origin, CompoundScope membersCache) throws FunctionDescriptorLookupError {
674 return !origin.isInterface() ?
675 false :
676 !membersCache.getElements(new DescriptorFilter(origin)).iterator().hasNext();
677 }
678 }
680 private MarkerCache markerCache = new MarkerCache();
682 /**
683 * Is given type a marker interface?
684 */
685 public boolean isMarkerInterface(Type site) {
686 return markerCache.get(site.tsym);
687 }
688 // </editor-fold>
690 // <editor-fold defaultstate="collapsed" desc="isSubtype">
691 /**
692 * Is t an unchecked subtype of s?
693 */
694 public boolean isSubtypeUnchecked(Type t, Type s) {
695 return isSubtypeUnchecked(t, s, noWarnings);
696 }
697 /**
698 * Is t an unchecked subtype of s?
699 */
700 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
701 boolean result = isSubtypeUncheckedInternal(t, s, warn);
702 if (result) {
703 checkUnsafeVarargsConversion(t, s, warn);
704 }
705 return result;
706 }
707 //where
708 private boolean isSubtypeUncheckedInternal(Type t, Type s, Warner warn) {
709 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
710 t = t.unannotatedType();
711 s = s.unannotatedType();
712 if (((ArrayType)t).elemtype.isPrimitive()) {
713 return isSameType(elemtype(t), elemtype(s));
714 } else {
715 return isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
716 }
717 } else if (isSubtype(t, s)) {
718 return true;
719 }
720 else if (t.tag == TYPEVAR) {
721 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
722 }
723 else if (!s.isRaw()) {
724 Type t2 = asSuper(t, s.tsym);
725 if (t2 != null && t2.isRaw()) {
726 if (isReifiable(s))
727 warn.silentWarn(LintCategory.UNCHECKED);
728 else
729 warn.warn(LintCategory.UNCHECKED);
730 return true;
731 }
732 }
733 return false;
734 }
736 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
737 if (t.tag != ARRAY || isReifiable(t))
738 return;
739 t = t.unannotatedType();
740 s = s.unannotatedType();
741 ArrayType from = (ArrayType)t;
742 boolean shouldWarn = false;
743 switch (s.tag) {
744 case ARRAY:
745 ArrayType to = (ArrayType)s;
746 shouldWarn = from.isVarargs() &&
747 !to.isVarargs() &&
748 !isReifiable(from);
749 break;
750 case CLASS:
751 shouldWarn = from.isVarargs();
752 break;
753 }
754 if (shouldWarn) {
755 warn.warn(LintCategory.VARARGS);
756 }
757 }
759 /**
760 * Is t a subtype of s?<br>
761 * (not defined for Method and ForAll types)
762 */
763 final public boolean isSubtype(Type t, Type s) {
764 return isSubtype(t, s, true);
765 }
766 final public boolean isSubtypeNoCapture(Type t, Type s) {
767 return isSubtype(t, s, false);
768 }
769 public boolean isSubtype(Type t, Type s, boolean capture) {
770 if (t == s)
771 return true;
773 t = t.unannotatedType();
774 s = s.unannotatedType();
776 if (t == s)
777 return true;
779 if (s.isPartial())
780 return isSuperType(s, t);
782 if (s.isCompound()) {
783 for (Type s2 : interfaces(s).prepend(supertype(s))) {
784 if (!isSubtype(t, s2, capture))
785 return false;
786 }
787 return true;
788 }
790 Type lower = lowerBound(s);
791 if (s != lower)
792 return isSubtype(capture ? capture(t) : t, lower, false);
794 return isSubtype.visit(capture ? capture(t) : t, s);
795 }
796 // where
797 private TypeRelation isSubtype = new TypeRelation()
798 {
799 public Boolean visitType(Type t, Type s) {
800 switch (t.tag) {
801 case BYTE:
802 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
803 case CHAR:
804 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
805 case SHORT: case INT: case LONG:
806 case FLOAT: case DOUBLE:
807 return t.getTag().isSubRangeOf(s.getTag());
808 case BOOLEAN: case VOID:
809 return t.hasTag(s.getTag());
810 case TYPEVAR:
811 return isSubtypeNoCapture(t.getUpperBound(), s);
812 case BOT:
813 return
814 s.hasTag(BOT) || s.hasTag(CLASS) ||
815 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
816 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
817 case NONE:
818 return false;
819 default:
820 throw new AssertionError("isSubtype " + t.tag);
821 }
822 }
824 private Set<TypePair> cache = new HashSet<TypePair>();
826 private boolean containsTypeRecursive(Type t, Type s) {
827 TypePair pair = new TypePair(t, s);
828 if (cache.add(pair)) {
829 try {
830 return containsType(t.getTypeArguments(),
831 s.getTypeArguments());
832 } finally {
833 cache.remove(pair);
834 }
835 } else {
836 return containsType(t.getTypeArguments(),
837 rewriteSupers(s).getTypeArguments());
838 }
839 }
841 private Type rewriteSupers(Type t) {
842 if (!t.isParameterized())
843 return t;
844 ListBuffer<Type> from = lb();
845 ListBuffer<Type> to = lb();
846 adaptSelf(t, from, to);
847 if (from.isEmpty())
848 return t;
849 ListBuffer<Type> rewrite = lb();
850 boolean changed = false;
851 for (Type orig : to.toList()) {
852 Type s = rewriteSupers(orig);
853 if (s.isSuperBound() && !s.isExtendsBound()) {
854 s = new WildcardType(syms.objectType,
855 BoundKind.UNBOUND,
856 syms.boundClass);
857 changed = true;
858 } else if (s != orig) {
859 s = new WildcardType(upperBound(s),
860 BoundKind.EXTENDS,
861 syms.boundClass);
862 changed = true;
863 }
864 rewrite.append(s);
865 }
866 if (changed)
867 return subst(t.tsym.type, from.toList(), rewrite.toList());
868 else
869 return t;
870 }
872 @Override
873 public Boolean visitClassType(ClassType t, Type s) {
874 Type sup = asSuper(t, s.tsym);
875 return sup != null
876 && sup.tsym == s.tsym
877 // You're not allowed to write
878 // Vector<Object> vec = new Vector<String>();
879 // But with wildcards you can write
880 // Vector<? extends Object> vec = new Vector<String>();
881 // which means that subtype checking must be done
882 // here instead of same-type checking (via containsType).
883 && (!s.isParameterized() || containsTypeRecursive(s, sup))
884 && isSubtypeNoCapture(sup.getEnclosingType(),
885 s.getEnclosingType());
886 }
888 @Override
889 public Boolean visitArrayType(ArrayType t, Type s) {
890 if (s.tag == ARRAY) {
891 if (t.elemtype.isPrimitive())
892 return isSameType(t.elemtype, elemtype(s));
893 else
894 return isSubtypeNoCapture(t.elemtype, elemtype(s));
895 }
897 if (s.tag == CLASS) {
898 Name sname = s.tsym.getQualifiedName();
899 return sname == names.java_lang_Object
900 || sname == names.java_lang_Cloneable
901 || sname == names.java_io_Serializable;
902 }
904 return false;
905 }
907 @Override
908 public Boolean visitUndetVar(UndetVar t, Type s) {
909 //todo: test against origin needed? or replace with substitution?
910 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN) {
911 return true;
912 } else if (s.tag == BOT) {
913 //if 's' is 'null' there's no instantiated type U for which
914 //U <: s (but 'null' itself, which is not a valid type)
915 return false;
916 }
918 t.addBound(InferenceBound.UPPER, s, Types.this);
919 return true;
920 }
922 @Override
923 public Boolean visitErrorType(ErrorType t, Type s) {
924 return true;
925 }
926 };
928 /**
929 * Is t a subtype of every type in given list `ts'?<br>
930 * (not defined for Method and ForAll types)<br>
931 * Allows unchecked conversions.
932 */
933 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
934 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
935 if (!isSubtypeUnchecked(t, l.head, warn))
936 return false;
937 return true;
938 }
940 /**
941 * Are corresponding elements of ts subtypes of ss? If lists are
942 * of different length, return false.
943 */
944 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
945 while (ts.tail != null && ss.tail != null
946 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
947 isSubtype(ts.head, ss.head)) {
948 ts = ts.tail;
949 ss = ss.tail;
950 }
951 return ts.tail == null && ss.tail == null;
952 /*inlined: ts.isEmpty() && ss.isEmpty();*/
953 }
955 /**
956 * Are corresponding elements of ts subtypes of ss, allowing
957 * unchecked conversions? If lists are of different length,
958 * return false.
959 **/
960 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
961 while (ts.tail != null && ss.tail != null
962 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
963 isSubtypeUnchecked(ts.head, ss.head, warn)) {
964 ts = ts.tail;
965 ss = ss.tail;
966 }
967 return ts.tail == null && ss.tail == null;
968 /*inlined: ts.isEmpty() && ss.isEmpty();*/
969 }
970 // </editor-fold>
972 // <editor-fold defaultstate="collapsed" desc="isSuperType">
973 /**
974 * Is t a supertype of s?
975 */
976 public boolean isSuperType(Type t, Type s) {
977 switch (t.tag) {
978 case ERROR:
979 return true;
980 case UNDETVAR: {
981 UndetVar undet = (UndetVar)t;
982 if (t == s ||
983 undet.qtype == s ||
984 s.tag == ERROR ||
985 s.tag == BOT) return true;
986 undet.addBound(InferenceBound.LOWER, s, this);
987 return true;
988 }
989 default:
990 return isSubtype(s, t);
991 }
992 }
993 // </editor-fold>
995 // <editor-fold defaultstate="collapsed" desc="isSameType">
996 /**
997 * Are corresponding elements of the lists the same type? If
998 * lists are of different length, return false.
999 */
1000 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
1001 return isSameTypes(ts, ss, false);
1002 }
1003 public boolean isSameTypes(List<Type> ts, List<Type> ss, boolean strict) {
1004 while (ts.tail != null && ss.tail != null
1005 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
1006 isSameType(ts.head, ss.head, strict)) {
1007 ts = ts.tail;
1008 ss = ss.tail;
1009 }
1010 return ts.tail == null && ss.tail == null;
1011 /*inlined: ts.isEmpty() && ss.isEmpty();*/
1012 }
1014 /**
1015 * Is t the same type as s?
1016 */
1017 public boolean isSameType(Type t, Type s) {
1018 return isSameType(t, s, false);
1019 }
1020 public boolean isSameType(Type t, Type s, boolean strict) {
1021 return strict ?
1022 isSameTypeStrict.visit(t, s) :
1023 isSameTypeLoose.visit(t, s);
1024 }
1025 // where
1026 abstract class SameTypeVisitor extends TypeRelation {
1028 public Boolean visitType(Type t, Type s) {
1029 if (t == s)
1030 return true;
1032 if (s.isPartial())
1033 return visit(s, t);
1035 switch (t.tag) {
1036 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1037 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
1038 return t.tag == s.tag;
1039 case TYPEVAR: {
1040 if (s.tag == TYPEVAR) {
1041 //type-substitution does not preserve type-var types
1042 //check that type var symbols and bounds are indeed the same
1043 return sameTypeVars((TypeVar)t, (TypeVar)s);
1044 }
1045 else {
1046 //special case for s == ? super X, where upper(s) = u
1047 //check that u == t, where u has been set by Type.withTypeVar
1048 return s.isSuperBound() &&
1049 !s.isExtendsBound() &&
1050 visit(t, upperBound(s));
1051 }
1052 }
1053 default:
1054 throw new AssertionError("isSameType " + t.tag);
1055 }
1056 }
1058 abstract boolean sameTypeVars(TypeVar tv1, TypeVar tv2);
1060 @Override
1061 public Boolean visitWildcardType(WildcardType t, Type s) {
1062 if (s.isPartial())
1063 return visit(s, t);
1064 else
1065 return false;
1066 }
1068 @Override
1069 public Boolean visitClassType(ClassType t, Type s) {
1070 if (t == s)
1071 return true;
1073 if (s.isPartial())
1074 return visit(s, t);
1076 if (s.isSuperBound() && !s.isExtendsBound())
1077 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
1079 if (t.isCompound() && s.isCompound()) {
1080 if (!visit(supertype(t), supertype(s)))
1081 return false;
1083 HashSet<UniqueType> set = new HashSet<UniqueType>();
1084 for (Type x : interfaces(t))
1085 set.add(new UniqueType(x, Types.this));
1086 for (Type x : interfaces(s)) {
1087 if (!set.remove(new UniqueType(x, Types.this)))
1088 return false;
1089 }
1090 return (set.isEmpty());
1091 }
1092 return t.tsym == s.tsym
1093 && visit(t.getEnclosingType(), s.getEnclosingType())
1094 && containsTypes(t.getTypeArguments(), s.getTypeArguments());
1095 }
1097 abstract protected boolean containsTypes(List<Type> ts1, List<Type> ts2);
1099 @Override
1100 public Boolean visitArrayType(ArrayType t, Type s) {
1101 if (t == s)
1102 return true;
1104 if (s.isPartial())
1105 return visit(s, t);
1107 return s.hasTag(ARRAY)
1108 && containsTypeEquivalent(t.elemtype, elemtype(s));
1109 }
1111 @Override
1112 public Boolean visitMethodType(MethodType t, Type s) {
1113 // isSameType for methods does not take thrown
1114 // exceptions into account!
1115 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
1116 }
1118 @Override
1119 public Boolean visitPackageType(PackageType t, Type s) {
1120 return t == s;
1121 }
1123 @Override
1124 public Boolean visitForAll(ForAll t, Type s) {
1125 if (s.tag != FORALL)
1126 return false;
1128 ForAll forAll = (ForAll)s;
1129 return hasSameBounds(t, forAll)
1130 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1131 }
1133 @Override
1134 public Boolean visitUndetVar(UndetVar t, Type s) {
1135 if (s.tag == WILDCARD)
1136 // FIXME, this might be leftovers from before capture conversion
1137 return false;
1139 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
1140 return true;
1142 t.addBound(InferenceBound.EQ, s, Types.this);
1144 return true;
1145 }
1147 @Override
1148 public Boolean visitErrorType(ErrorType t, Type s) {
1149 return true;
1150 }
1151 }
1153 /**
1154 * Standard type-equality relation - type variables are considered
1155 * equals if they share the same type symbol.
1156 */
1157 TypeRelation isSameTypeLoose = new SameTypeVisitor() {
1158 @Override
1159 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
1160 return tv1.tsym == tv2.tsym && visit(tv1.getUpperBound(), tv2.getUpperBound());
1161 }
1162 @Override
1163 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
1164 return containsTypeEquivalent(ts1, ts2);
1165 }
1166 };
1168 /**
1169 * Strict type-equality relation - type variables are considered
1170 * equals if they share the same object identity.
1171 */
1172 TypeRelation isSameTypeStrict = new SameTypeVisitor() {
1173 @Override
1174 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
1175 return tv1 == tv2;
1176 }
1177 @Override
1178 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
1179 return isSameTypes(ts1, ts2, true);
1180 }
1181 };
1182 // </editor-fold>
1184 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1185 public boolean containedBy(Type t, Type s) {
1186 switch (t.tag) {
1187 case UNDETVAR:
1188 if (s.tag == WILDCARD) {
1189 UndetVar undetvar = (UndetVar)t;
1190 WildcardType wt = (WildcardType)s;
1191 switch(wt.kind) {
1192 case UNBOUND: //similar to ? extends Object
1193 case EXTENDS: {
1194 Type bound = upperBound(s);
1195 undetvar.addBound(InferenceBound.UPPER, bound, this);
1196 break;
1197 }
1198 case SUPER: {
1199 Type bound = lowerBound(s);
1200 undetvar.addBound(InferenceBound.LOWER, bound, this);
1201 break;
1202 }
1203 }
1204 return true;
1205 } else {
1206 return isSameType(t, s);
1207 }
1208 case ERROR:
1209 return true;
1210 default:
1211 return containsType(s, t);
1212 }
1213 }
1215 boolean containsType(List<Type> ts, List<Type> ss) {
1216 while (ts.nonEmpty() && ss.nonEmpty()
1217 && containsType(ts.head, ss.head)) {
1218 ts = ts.tail;
1219 ss = ss.tail;
1220 }
1221 return ts.isEmpty() && ss.isEmpty();
1222 }
1224 /**
1225 * Check if t contains s.
1226 *
1227 * <p>T contains S if:
1228 *
1229 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1230 *
1231 * <p>This relation is only used by ClassType.isSubtype(), that
1232 * is,
1233 *
1234 * <p>{@code C<S> <: C<T> if T contains S.}
1235 *
1236 * <p>Because of F-bounds, this relation can lead to infinite
1237 * recursion. Thus we must somehow break that recursion. Notice
1238 * that containsType() is only called from ClassType.isSubtype().
1239 * Since the arguments have already been checked against their
1240 * bounds, we know:
1241 *
1242 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1243 *
1244 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1245 *
1246 * @param t a type
1247 * @param s a type
1248 */
1249 public boolean containsType(Type t, Type s) {
1250 return containsType.visit(t, s);
1251 }
1252 // where
1253 private TypeRelation containsType = new TypeRelation() {
1255 private Type U(Type t) {
1256 while (t.tag == WILDCARD) {
1257 WildcardType w = (WildcardType)t;
1258 if (w.isSuperBound())
1259 return w.bound == null ? syms.objectType : w.bound.bound;
1260 else
1261 t = w.type;
1262 }
1263 return t;
1264 }
1266 private Type L(Type t) {
1267 while (t.tag == WILDCARD) {
1268 WildcardType w = (WildcardType)t;
1269 if (w.isExtendsBound())
1270 return syms.botType;
1271 else
1272 t = w.type;
1273 }
1274 return t;
1275 }
1277 public Boolean visitType(Type t, Type s) {
1278 if (s.isPartial())
1279 return containedBy(s, t);
1280 else
1281 return isSameType(t, s);
1282 }
1284 // void debugContainsType(WildcardType t, Type s) {
1285 // System.err.println();
1286 // System.err.format(" does %s contain %s?%n", t, s);
1287 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1288 // upperBound(s), s, t, U(t),
1289 // t.isSuperBound()
1290 // || isSubtypeNoCapture(upperBound(s), U(t)));
1291 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1292 // L(t), t, s, lowerBound(s),
1293 // t.isExtendsBound()
1294 // || isSubtypeNoCapture(L(t), lowerBound(s)));
1295 // System.err.println();
1296 // }
1298 @Override
1299 public Boolean visitWildcardType(WildcardType t, Type s) {
1300 if (s.isPartial())
1301 return containedBy(s, t);
1302 else {
1303 // debugContainsType(t, s);
1304 return isSameWildcard(t, s)
1305 || isCaptureOf(s, t)
1306 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
1307 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
1308 }
1309 }
1311 @Override
1312 public Boolean visitUndetVar(UndetVar t, Type s) {
1313 if (s.tag != WILDCARD)
1314 return isSameType(t, s);
1315 else
1316 return false;
1317 }
1319 @Override
1320 public Boolean visitErrorType(ErrorType t, Type s) {
1321 return true;
1322 }
1323 };
1325 public boolean isCaptureOf(Type s, WildcardType t) {
1326 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
1327 return false;
1328 return isSameWildcard(t, ((CapturedType)s).wildcard);
1329 }
1331 public boolean isSameWildcard(WildcardType t, Type s) {
1332 if (s.tag != WILDCARD)
1333 return false;
1334 WildcardType w = (WildcardType)s;
1335 return w.kind == t.kind && w.type == t.type;
1336 }
1338 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1339 while (ts.nonEmpty() && ss.nonEmpty()
1340 && containsTypeEquivalent(ts.head, ss.head)) {
1341 ts = ts.tail;
1342 ss = ss.tail;
1343 }
1344 return ts.isEmpty() && ss.isEmpty();
1345 }
1346 // </editor-fold>
1348 // <editor-fold defaultstate="collapsed" desc="isCastable">
1349 public boolean isCastable(Type t, Type s) {
1350 return isCastable(t, s, noWarnings);
1351 }
1353 /**
1354 * Is t is castable to s?<br>
1355 * s is assumed to be an erased type.<br>
1356 * (not defined for Method and ForAll types).
1357 */
1358 public boolean isCastable(Type t, Type s, Warner warn) {
1359 if (t == s)
1360 return true;
1362 if (t.isPrimitive() != s.isPrimitive())
1363 return allowBoxing && (
1364 isConvertible(t, s, warn)
1365 || (allowObjectToPrimitiveCast &&
1366 s.isPrimitive() &&
1367 isSubtype(boxedClass(s).type, t)));
1368 if (warn != warnStack.head) {
1369 try {
1370 warnStack = warnStack.prepend(warn);
1371 checkUnsafeVarargsConversion(t, s, warn);
1372 return isCastable.visit(t,s);
1373 } finally {
1374 warnStack = warnStack.tail;
1375 }
1376 } else {
1377 return isCastable.visit(t,s);
1378 }
1379 }
1380 // where
1381 private TypeRelation isCastable = new TypeRelation() {
1383 public Boolean visitType(Type t, Type s) {
1384 if (s.tag == ERROR)
1385 return true;
1387 switch (t.tag) {
1388 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1389 case DOUBLE:
1390 return s.isNumeric();
1391 case BOOLEAN:
1392 return s.tag == BOOLEAN;
1393 case VOID:
1394 return false;
1395 case BOT:
1396 return isSubtype(t, s);
1397 default:
1398 throw new AssertionError();
1399 }
1400 }
1402 @Override
1403 public Boolean visitWildcardType(WildcardType t, Type s) {
1404 return isCastable(upperBound(t), s, warnStack.head);
1405 }
1407 @Override
1408 public Boolean visitClassType(ClassType t, Type s) {
1409 if (s.tag == ERROR || s.tag == BOT)
1410 return true;
1412 if (s.tag == TYPEVAR) {
1413 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1414 warnStack.head.warn(LintCategory.UNCHECKED);
1415 return true;
1416 } else {
1417 return false;
1418 }
1419 }
1421 if (t.isCompound()) {
1422 Warner oldWarner = warnStack.head;
1423 warnStack.head = noWarnings;
1424 if (!visit(supertype(t), s))
1425 return false;
1426 for (Type intf : interfaces(t)) {
1427 if (!visit(intf, s))
1428 return false;
1429 }
1430 if (warnStack.head.hasLint(LintCategory.UNCHECKED))
1431 oldWarner.warn(LintCategory.UNCHECKED);
1432 return true;
1433 }
1435 if (s.isCompound()) {
1436 // call recursively to reuse the above code
1437 return visitClassType((ClassType)s, t);
1438 }
1440 if (s.tag == CLASS || s.tag == ARRAY) {
1441 boolean upcast;
1442 if ((upcast = isSubtype(erasure(t), erasure(s)))
1443 || isSubtype(erasure(s), erasure(t))) {
1444 if (!upcast && s.tag == ARRAY) {
1445 if (!isReifiable(s))
1446 warnStack.head.warn(LintCategory.UNCHECKED);
1447 return true;
1448 } else if (s.isRaw()) {
1449 return true;
1450 } else if (t.isRaw()) {
1451 if (!isUnbounded(s))
1452 warnStack.head.warn(LintCategory.UNCHECKED);
1453 return true;
1454 }
1455 // Assume |a| <: |b|
1456 final Type a = upcast ? t : s;
1457 final Type b = upcast ? s : t;
1458 final boolean HIGH = true;
1459 final boolean LOW = false;
1460 final boolean DONT_REWRITE_TYPEVARS = false;
1461 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1462 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1463 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1464 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1465 Type lowSub = asSub(bLow, aLow.tsym);
1466 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1467 if (highSub == null) {
1468 final boolean REWRITE_TYPEVARS = true;
1469 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1470 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1471 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1472 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1473 lowSub = asSub(bLow, aLow.tsym);
1474 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1475 }
1476 if (highSub != null) {
1477 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1478 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1479 }
1480 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1481 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1482 && !disjointTypes(aLow.allparams(), highSub.allparams())
1483 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1484 if (upcast ? giveWarning(a, b) :
1485 giveWarning(b, a))
1486 warnStack.head.warn(LintCategory.UNCHECKED);
1487 return true;
1488 }
1489 }
1490 if (isReifiable(s))
1491 return isSubtypeUnchecked(a, b);
1492 else
1493 return isSubtypeUnchecked(a, b, warnStack.head);
1494 }
1496 // Sidecast
1497 if (s.tag == CLASS) {
1498 if ((s.tsym.flags() & INTERFACE) != 0) {
1499 return ((t.tsym.flags() & FINAL) == 0)
1500 ? sideCast(t, s, warnStack.head)
1501 : sideCastFinal(t, s, warnStack.head);
1502 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1503 return ((s.tsym.flags() & FINAL) == 0)
1504 ? sideCast(t, s, warnStack.head)
1505 : sideCastFinal(t, s, warnStack.head);
1506 } else {
1507 // unrelated class types
1508 return false;
1509 }
1510 }
1511 }
1512 return false;
1513 }
1515 @Override
1516 public Boolean visitArrayType(ArrayType t, Type s) {
1517 switch (s.tag) {
1518 case ERROR:
1519 case BOT:
1520 return true;
1521 case TYPEVAR:
1522 if (isCastable(s, t, noWarnings)) {
1523 warnStack.head.warn(LintCategory.UNCHECKED);
1524 return true;
1525 } else {
1526 return false;
1527 }
1528 case CLASS:
1529 return isSubtype(t, s);
1530 case ARRAY:
1531 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1532 return elemtype(t).tag == elemtype(s).tag;
1533 } else {
1534 return visit(elemtype(t), elemtype(s));
1535 }
1536 default:
1537 return false;
1538 }
1539 }
1541 @Override
1542 public Boolean visitTypeVar(TypeVar t, Type s) {
1543 switch (s.tag) {
1544 case ERROR:
1545 case BOT:
1546 return true;
1547 case TYPEVAR:
1548 if (isSubtype(t, s)) {
1549 return true;
1550 } else if (isCastable(t.bound, s, noWarnings)) {
1551 warnStack.head.warn(LintCategory.UNCHECKED);
1552 return true;
1553 } else {
1554 return false;
1555 }
1556 default:
1557 return isCastable(t.bound, s, warnStack.head);
1558 }
1559 }
1561 @Override
1562 public Boolean visitErrorType(ErrorType t, Type s) {
1563 return true;
1564 }
1565 };
1566 // </editor-fold>
1568 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1569 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1570 while (ts.tail != null && ss.tail != null) {
1571 if (disjointType(ts.head, ss.head)) return true;
1572 ts = ts.tail;
1573 ss = ss.tail;
1574 }
1575 return false;
1576 }
1578 /**
1579 * Two types or wildcards are considered disjoint if it can be
1580 * proven that no type can be contained in both. It is
1581 * conservative in that it is allowed to say that two types are
1582 * not disjoint, even though they actually are.
1583 *
1584 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1585 * {@code X} and {@code Y} are not disjoint.
1586 */
1587 public boolean disjointType(Type t, Type s) {
1588 return disjointType.visit(t, s);
1589 }
1590 // where
1591 private TypeRelation disjointType = new TypeRelation() {
1593 private Set<TypePair> cache = new HashSet<TypePair>();
1595 public Boolean visitType(Type t, Type s) {
1596 if (s.tag == WILDCARD)
1597 return visit(s, t);
1598 else
1599 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1600 }
1602 private boolean isCastableRecursive(Type t, Type s) {
1603 TypePair pair = new TypePair(t, s);
1604 if (cache.add(pair)) {
1605 try {
1606 return Types.this.isCastable(t, s);
1607 } finally {
1608 cache.remove(pair);
1609 }
1610 } else {
1611 return true;
1612 }
1613 }
1615 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1616 TypePair pair = new TypePair(t, s);
1617 if (cache.add(pair)) {
1618 try {
1619 return Types.this.notSoftSubtype(t, s);
1620 } finally {
1621 cache.remove(pair);
1622 }
1623 } else {
1624 return false;
1625 }
1626 }
1628 @Override
1629 public Boolean visitWildcardType(WildcardType t, Type s) {
1630 if (t.isUnbound())
1631 return false;
1633 if (s.tag != WILDCARD) {
1634 if (t.isExtendsBound())
1635 return notSoftSubtypeRecursive(s, t.type);
1636 else // isSuperBound()
1637 return notSoftSubtypeRecursive(t.type, s);
1638 }
1640 if (s.isUnbound())
1641 return false;
1643 if (t.isExtendsBound()) {
1644 if (s.isExtendsBound())
1645 return !isCastableRecursive(t.type, upperBound(s));
1646 else if (s.isSuperBound())
1647 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1648 } else if (t.isSuperBound()) {
1649 if (s.isExtendsBound())
1650 return notSoftSubtypeRecursive(t.type, upperBound(s));
1651 }
1652 return false;
1653 }
1654 };
1655 // </editor-fold>
1657 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1658 /**
1659 * Returns the lower bounds of the formals of a method.
1660 */
1661 public List<Type> lowerBoundArgtypes(Type t) {
1662 return lowerBounds(t.getParameterTypes());
1663 }
1664 public List<Type> lowerBounds(List<Type> ts) {
1665 return map(ts, lowerBoundMapping);
1666 }
1667 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1668 public Type apply(Type t) {
1669 return lowerBound(t);
1670 }
1671 };
1672 // </editor-fold>
1674 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1675 /**
1676 * This relation answers the question: is impossible that
1677 * something of type `t' can be a subtype of `s'? This is
1678 * different from the question "is `t' not a subtype of `s'?"
1679 * when type variables are involved: Integer is not a subtype of T
1680 * where {@code <T extends Number>} but it is not true that Integer cannot
1681 * possibly be a subtype of T.
1682 */
1683 public boolean notSoftSubtype(Type t, Type s) {
1684 if (t == s) return false;
1685 if (t.tag == TYPEVAR) {
1686 TypeVar tv = (TypeVar) t;
1687 return !isCastable(tv.bound,
1688 relaxBound(s),
1689 noWarnings);
1690 }
1691 if (s.tag != WILDCARD)
1692 s = upperBound(s);
1694 return !isSubtype(t, relaxBound(s));
1695 }
1697 private Type relaxBound(Type t) {
1698 if (t.tag == TYPEVAR) {
1699 while (t.tag == TYPEVAR)
1700 t = t.getUpperBound();
1701 t = rewriteQuantifiers(t, true, true);
1702 }
1703 return t;
1704 }
1705 // </editor-fold>
1707 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1708 public boolean isReifiable(Type t) {
1709 return isReifiable.visit(t);
1710 }
1711 // where
1712 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1714 public Boolean visitType(Type t, Void ignored) {
1715 return true;
1716 }
1718 @Override
1719 public Boolean visitClassType(ClassType t, Void ignored) {
1720 if (t.isCompound())
1721 return false;
1722 else {
1723 if (!t.isParameterized())
1724 return true;
1726 for (Type param : t.allparams()) {
1727 if (!param.isUnbound())
1728 return false;
1729 }
1730 return true;
1731 }
1732 }
1734 @Override
1735 public Boolean visitArrayType(ArrayType t, Void ignored) {
1736 return visit(t.elemtype);
1737 }
1739 @Override
1740 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1741 return false;
1742 }
1743 };
1744 // </editor-fold>
1746 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1747 public boolean isArray(Type t) {
1748 while (t.tag == WILDCARD)
1749 t = upperBound(t);
1750 return t.tag == ARRAY;
1751 }
1753 /**
1754 * The element type of an array.
1755 */
1756 public Type elemtype(Type t) {
1757 switch (t.tag) {
1758 case WILDCARD:
1759 return elemtype(upperBound(t));
1760 case ARRAY:
1761 t = t.unannotatedType();
1762 return ((ArrayType)t).elemtype;
1763 case FORALL:
1764 return elemtype(((ForAll)t).qtype);
1765 case ERROR:
1766 return t;
1767 default:
1768 return null;
1769 }
1770 }
1772 public Type elemtypeOrType(Type t) {
1773 Type elemtype = elemtype(t);
1774 return elemtype != null ?
1775 elemtype :
1776 t;
1777 }
1779 /**
1780 * Mapping to take element type of an arraytype
1781 */
1782 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1783 public Type apply(Type t) { return elemtype(t); }
1784 };
1786 /**
1787 * The number of dimensions of an array type.
1788 */
1789 public int dimensions(Type t) {
1790 int result = 0;
1791 while (t.tag == ARRAY) {
1792 result++;
1793 t = elemtype(t);
1794 }
1795 return result;
1796 }
1798 /**
1799 * Returns an ArrayType with the component type t
1800 *
1801 * @param t The component type of the ArrayType
1802 * @return the ArrayType for the given component
1803 */
1804 public ArrayType makeArrayType(Type t) {
1805 if (t.tag == VOID ||
1806 t.tag == PACKAGE) {
1807 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
1808 }
1809 return new ArrayType(t, syms.arrayClass);
1810 }
1811 // </editor-fold>
1813 // <editor-fold defaultstate="collapsed" desc="asSuper">
1814 /**
1815 * Return the (most specific) base type of t that starts with the
1816 * given symbol. If none exists, return null.
1817 *
1818 * @param t a type
1819 * @param sym a symbol
1820 */
1821 public Type asSuper(Type t, Symbol sym) {
1822 return asSuper.visit(t, sym);
1823 }
1824 // where
1825 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1827 public Type visitType(Type t, Symbol sym) {
1828 return null;
1829 }
1831 @Override
1832 public Type visitClassType(ClassType t, Symbol sym) {
1833 if (t.tsym == sym)
1834 return t;
1836 Type st = supertype(t);
1837 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1838 Type x = asSuper(st, sym);
1839 if (x != null)
1840 return x;
1841 }
1842 if ((sym.flags() & INTERFACE) != 0) {
1843 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1844 Type x = asSuper(l.head, sym);
1845 if (x != null)
1846 return x;
1847 }
1848 }
1849 return null;
1850 }
1852 @Override
1853 public Type visitArrayType(ArrayType t, Symbol sym) {
1854 return isSubtype(t, sym.type) ? sym.type : null;
1855 }
1857 @Override
1858 public Type visitTypeVar(TypeVar t, Symbol sym) {
1859 if (t.tsym == sym)
1860 return t;
1861 else
1862 return asSuper(t.bound, sym);
1863 }
1865 @Override
1866 public Type visitErrorType(ErrorType t, Symbol sym) {
1867 return t;
1868 }
1869 };
1871 /**
1872 * Return the base type of t or any of its outer types that starts
1873 * with the given symbol. If none exists, return null.
1874 *
1875 * @param t a type
1876 * @param sym a symbol
1877 */
1878 public Type asOuterSuper(Type t, Symbol sym) {
1879 switch (t.tag) {
1880 case CLASS:
1881 do {
1882 Type s = asSuper(t, sym);
1883 if (s != null) return s;
1884 t = t.getEnclosingType();
1885 } while (t.tag == CLASS);
1886 return null;
1887 case ARRAY:
1888 return isSubtype(t, sym.type) ? sym.type : null;
1889 case TYPEVAR:
1890 return asSuper(t, sym);
1891 case ERROR:
1892 return t;
1893 default:
1894 return null;
1895 }
1896 }
1898 /**
1899 * Return the base type of t or any of its enclosing types that
1900 * starts with the given symbol. If none exists, return null.
1901 *
1902 * @param t a type
1903 * @param sym a symbol
1904 */
1905 public Type asEnclosingSuper(Type t, Symbol sym) {
1906 switch (t.tag) {
1907 case CLASS:
1908 do {
1909 Type s = asSuper(t, sym);
1910 if (s != null) return s;
1911 Type outer = t.getEnclosingType();
1912 t = (outer.tag == CLASS) ? outer :
1913 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1914 Type.noType;
1915 } while (t.tag == CLASS);
1916 return null;
1917 case ARRAY:
1918 return isSubtype(t, sym.type) ? sym.type : null;
1919 case TYPEVAR:
1920 return asSuper(t, sym);
1921 case ERROR:
1922 return t;
1923 default:
1924 return null;
1925 }
1926 }
1927 // </editor-fold>
1929 // <editor-fold defaultstate="collapsed" desc="memberType">
1930 /**
1931 * The type of given symbol, seen as a member of t.
1932 *
1933 * @param t a type
1934 * @param sym a symbol
1935 */
1936 public Type memberType(Type t, Symbol sym) {
1937 return (sym.flags() & STATIC) != 0
1938 ? sym.type
1939 : memberType.visit(t, sym);
1940 }
1941 // where
1942 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1944 public Type visitType(Type t, Symbol sym) {
1945 return sym.type;
1946 }
1948 @Override
1949 public Type visitWildcardType(WildcardType t, Symbol sym) {
1950 return memberType(upperBound(t), sym);
1951 }
1953 @Override
1954 public Type visitClassType(ClassType t, Symbol sym) {
1955 Symbol owner = sym.owner;
1956 long flags = sym.flags();
1957 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1958 Type base = asOuterSuper(t, owner);
1959 //if t is an intersection type T = CT & I1 & I2 ... & In
1960 //its supertypes CT, I1, ... In might contain wildcards
1961 //so we need to go through capture conversion
1962 base = t.isCompound() ? capture(base) : base;
1963 if (base != null) {
1964 List<Type> ownerParams = owner.type.allparams();
1965 List<Type> baseParams = base.allparams();
1966 if (ownerParams.nonEmpty()) {
1967 if (baseParams.isEmpty()) {
1968 // then base is a raw type
1969 return erasure(sym.type);
1970 } else {
1971 return subst(sym.type, ownerParams, baseParams);
1972 }
1973 }
1974 }
1975 }
1976 return sym.type;
1977 }
1979 @Override
1980 public Type visitTypeVar(TypeVar t, Symbol sym) {
1981 return memberType(t.bound, sym);
1982 }
1984 @Override
1985 public Type visitErrorType(ErrorType t, Symbol sym) {
1986 return t;
1987 }
1988 };
1989 // </editor-fold>
1991 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1992 public boolean isAssignable(Type t, Type s) {
1993 return isAssignable(t, s, noWarnings);
1994 }
1996 /**
1997 * Is t assignable to s?<br>
1998 * Equivalent to subtype except for constant values and raw
1999 * types.<br>
2000 * (not defined for Method and ForAll types)
2001 */
2002 public boolean isAssignable(Type t, Type s, Warner warn) {
2003 if (t.tag == ERROR)
2004 return true;
2005 if (t.tag.isSubRangeOf(INT) && t.constValue() != null) {
2006 int value = ((Number)t.constValue()).intValue();
2007 switch (s.tag) {
2008 case BYTE:
2009 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
2010 return true;
2011 break;
2012 case CHAR:
2013 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
2014 return true;
2015 break;
2016 case SHORT:
2017 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
2018 return true;
2019 break;
2020 case INT:
2021 return true;
2022 case CLASS:
2023 switch (unboxedType(s).tag) {
2024 case BYTE:
2025 case CHAR:
2026 case SHORT:
2027 return isAssignable(t, unboxedType(s), warn);
2028 }
2029 break;
2030 }
2031 }
2032 return isConvertible(t, s, warn);
2033 }
2034 // </editor-fold>
2036 // <editor-fold defaultstate="collapsed" desc="erasure">
2037 /**
2038 * The erasure of t {@code |t|} -- the type that results when all
2039 * type parameters in t are deleted.
2040 */
2041 public Type erasure(Type t) {
2042 return eraseNotNeeded(t)? t : erasure(t, false);
2043 }
2044 //where
2045 private boolean eraseNotNeeded(Type t) {
2046 // We don't want to erase primitive types and String type as that
2047 // operation is idempotent. Also, erasing these could result in loss
2048 // of information such as constant values attached to such types.
2049 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2050 }
2052 private Type erasure(Type t, boolean recurse) {
2053 if (t.isPrimitive())
2054 return t; /* fast special case */
2055 else
2056 return erasure.visit(t, recurse);
2057 }
2058 // where
2059 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
2060 public Type visitType(Type t, Boolean recurse) {
2061 if (t.isPrimitive())
2062 return t; /*fast special case*/
2063 else
2064 return t.map(recurse ? erasureRecFun : erasureFun);
2065 }
2067 @Override
2068 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2069 return erasure(upperBound(t), recurse);
2070 }
2072 @Override
2073 public Type visitClassType(ClassType t, Boolean recurse) {
2074 Type erased = t.tsym.erasure(Types.this);
2075 if (recurse) {
2076 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
2077 }
2078 return erased;
2079 }
2081 @Override
2082 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2083 return erasure(t.bound, recurse);
2084 }
2086 @Override
2087 public Type visitErrorType(ErrorType t, Boolean recurse) {
2088 return t;
2089 }
2091 @Override
2092 public Type visitAnnotatedType(AnnotatedType t, Boolean recurse) {
2093 Type erased = erasure(t.underlyingType, recurse);
2094 if (erased.getKind() == TypeKind.ANNOTATED) {
2095 // This can only happen when the underlying type is a
2096 // type variable and the upper bound of it is annotated.
2097 // The annotation on the type variable overrides the one
2098 // on the bound.
2099 erased = ((AnnotatedType)erased).underlyingType;
2100 }
2101 return new AnnotatedType(t.typeAnnotations, erased);
2102 }
2103 };
2105 private Mapping erasureFun = new Mapping ("erasure") {
2106 public Type apply(Type t) { return erasure(t); }
2107 };
2109 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
2110 public Type apply(Type t) { return erasureRecursive(t); }
2111 };
2113 public List<Type> erasure(List<Type> ts) {
2114 return Type.map(ts, erasureFun);
2115 }
2117 public Type erasureRecursive(Type t) {
2118 return erasure(t, true);
2119 }
2121 public List<Type> erasureRecursive(List<Type> ts) {
2122 return Type.map(ts, erasureRecFun);
2123 }
2124 // </editor-fold>
2126 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
2127 /**
2128 * Make a compound type from non-empty list of types
2129 *
2130 * @param bounds the types from which the compound type is formed
2131 * @param supertype is objectType if all bounds are interfaces,
2132 * null otherwise.
2133 */
2134 public Type makeCompoundType(List<Type> bounds) {
2135 return makeCompoundType(bounds, bounds.head.tsym.isInterface());
2136 }
2137 public Type makeCompoundType(List<Type> bounds, boolean allInterfaces) {
2138 Assert.check(bounds.nonEmpty());
2139 Type firstExplicitBound = bounds.head;
2140 if (allInterfaces) {
2141 bounds = bounds.prepend(syms.objectType);
2142 }
2143 ClassSymbol bc =
2144 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2145 Type.moreInfo
2146 ? names.fromString(bounds.toString())
2147 : names.empty,
2148 null,
2149 syms.noSymbol);
2150 bc.type = new IntersectionClassType(bounds, bc, allInterfaces);
2151 bc.erasure_field = (bounds.head.tag == TYPEVAR) ?
2152 syms.objectType : // error condition, recover
2153 erasure(firstExplicitBound);
2154 bc.members_field = new Scope(bc);
2155 return bc.type;
2156 }
2158 /**
2159 * A convenience wrapper for {@link #makeCompoundType(List)}; the
2160 * arguments are converted to a list and passed to the other
2161 * method. Note that this might cause a symbol completion.
2162 * Hence, this version of makeCompoundType may not be called
2163 * during a classfile read.
2164 */
2165 public Type makeCompoundType(Type bound1, Type bound2) {
2166 return makeCompoundType(List.of(bound1, bound2));
2167 }
2168 // </editor-fold>
2170 // <editor-fold defaultstate="collapsed" desc="supertype">
2171 public Type supertype(Type t) {
2172 return supertype.visit(t);
2173 }
2174 // where
2175 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2177 public Type visitType(Type t, Void ignored) {
2178 // A note on wildcards: there is no good way to
2179 // determine a supertype for a super bounded wildcard.
2180 return null;
2181 }
2183 @Override
2184 public Type visitClassType(ClassType t, Void ignored) {
2185 if (t.supertype_field == null) {
2186 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2187 // An interface has no superclass; its supertype is Object.
2188 if (t.isInterface())
2189 supertype = ((ClassType)t.tsym.type).supertype_field;
2190 if (t.supertype_field == null) {
2191 List<Type> actuals = classBound(t).allparams();
2192 List<Type> formals = t.tsym.type.allparams();
2193 if (t.hasErasedSupertypes()) {
2194 t.supertype_field = erasureRecursive(supertype);
2195 } else if (formals.nonEmpty()) {
2196 t.supertype_field = subst(supertype, formals, actuals);
2197 }
2198 else {
2199 t.supertype_field = supertype;
2200 }
2201 }
2202 }
2203 return t.supertype_field;
2204 }
2206 /**
2207 * The supertype is always a class type. If the type
2208 * variable's bounds start with a class type, this is also
2209 * the supertype. Otherwise, the supertype is
2210 * java.lang.Object.
2211 */
2212 @Override
2213 public Type visitTypeVar(TypeVar t, Void ignored) {
2214 if (t.bound.tag == TYPEVAR ||
2215 (!t.bound.isCompound() && !t.bound.isInterface())) {
2216 return t.bound;
2217 } else {
2218 return supertype(t.bound);
2219 }
2220 }
2222 @Override
2223 public Type visitArrayType(ArrayType t, Void ignored) {
2224 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2225 return arraySuperType();
2226 else
2227 return new ArrayType(supertype(t.elemtype), t.tsym);
2228 }
2230 @Override
2231 public Type visitErrorType(ErrorType t, Void ignored) {
2232 return t;
2233 }
2234 };
2235 // </editor-fold>
2237 // <editor-fold defaultstate="collapsed" desc="interfaces">
2238 /**
2239 * Return the interfaces implemented by this class.
2240 */
2241 public List<Type> interfaces(Type t) {
2242 return interfaces.visit(t);
2243 }
2244 // where
2245 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2247 public List<Type> visitType(Type t, Void ignored) {
2248 return List.nil();
2249 }
2251 @Override
2252 public List<Type> visitClassType(ClassType t, Void ignored) {
2253 if (t.interfaces_field == null) {
2254 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2255 if (t.interfaces_field == null) {
2256 // If t.interfaces_field is null, then t must
2257 // be a parameterized type (not to be confused
2258 // with a generic type declaration).
2259 // Terminology:
2260 // Parameterized type: List<String>
2261 // Generic type declaration: class List<E> { ... }
2262 // So t corresponds to List<String> and
2263 // t.tsym.type corresponds to List<E>.
2264 // The reason t must be parameterized type is
2265 // that completion will happen as a side
2266 // effect of calling
2267 // ClassSymbol.getInterfaces. Since
2268 // t.interfaces_field is null after
2269 // completion, we can assume that t is not the
2270 // type of a class/interface declaration.
2271 Assert.check(t != t.tsym.type, t);
2272 List<Type> actuals = t.allparams();
2273 List<Type> formals = t.tsym.type.allparams();
2274 if (t.hasErasedSupertypes()) {
2275 t.interfaces_field = erasureRecursive(interfaces);
2276 } else if (formals.nonEmpty()) {
2277 t.interfaces_field =
2278 upperBounds(subst(interfaces, formals, actuals));
2279 }
2280 else {
2281 t.interfaces_field = interfaces;
2282 }
2283 }
2284 }
2285 return t.interfaces_field;
2286 }
2288 @Override
2289 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2290 if (t.bound.isCompound())
2291 return interfaces(t.bound);
2293 if (t.bound.isInterface())
2294 return List.of(t.bound);
2296 return List.nil();
2297 }
2298 };
2300 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2301 for (Type i2 : interfaces(origin.type)) {
2302 if (isym == i2.tsym) return true;
2303 }
2304 return false;
2305 }
2306 // </editor-fold>
2308 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2309 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
2311 public boolean isDerivedRaw(Type t) {
2312 Boolean result = isDerivedRawCache.get(t);
2313 if (result == null) {
2314 result = isDerivedRawInternal(t);
2315 isDerivedRawCache.put(t, result);
2316 }
2317 return result;
2318 }
2320 public boolean isDerivedRawInternal(Type t) {
2321 if (t.isErroneous())
2322 return false;
2323 return
2324 t.isRaw() ||
2325 supertype(t) != null && isDerivedRaw(supertype(t)) ||
2326 isDerivedRaw(interfaces(t));
2327 }
2329 public boolean isDerivedRaw(List<Type> ts) {
2330 List<Type> l = ts;
2331 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2332 return l.nonEmpty();
2333 }
2334 // </editor-fold>
2336 // <editor-fold defaultstate="collapsed" desc="setBounds">
2337 /**
2338 * Set the bounds field of the given type variable to reflect a
2339 * (possibly multiple) list of bounds.
2340 * @param t a type variable
2341 * @param bounds the bounds, must be nonempty
2342 * @param supertype is objectType if all bounds are interfaces,
2343 * null otherwise.
2344 */
2345 public void setBounds(TypeVar t, List<Type> bounds) {
2346 setBounds(t, bounds, bounds.head.tsym.isInterface());
2347 }
2349 /**
2350 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
2351 * third parameter is computed directly, as follows: if all
2352 * all bounds are interface types, the computed supertype is Object,
2353 * otherwise the supertype is simply left null (in this case, the supertype
2354 * is assumed to be the head of the bound list passed as second argument).
2355 * Note that this check might cause a symbol completion. Hence, this version of
2356 * setBounds may not be called during a classfile read.
2357 */
2358 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2359 t.bound = bounds.tail.isEmpty() ?
2360 bounds.head :
2361 makeCompoundType(bounds, allInterfaces);
2362 t.rank_field = -1;
2363 }
2364 // </editor-fold>
2366 // <editor-fold defaultstate="collapsed" desc="getBounds">
2367 /**
2368 * Return list of bounds of the given type variable.
2369 */
2370 public List<Type> getBounds(TypeVar t) {
2371 if (t.bound.hasTag(NONE))
2372 return List.nil();
2373 else if (t.bound.isErroneous() || !t.bound.isCompound())
2374 return List.of(t.bound);
2375 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2376 return interfaces(t).prepend(supertype(t));
2377 else
2378 // No superclass was given in bounds.
2379 // In this case, supertype is Object, erasure is first interface.
2380 return interfaces(t);
2381 }
2382 // </editor-fold>
2384 // <editor-fold defaultstate="collapsed" desc="classBound">
2385 /**
2386 * If the given type is a (possibly selected) type variable,
2387 * return the bounding class of this type, otherwise return the
2388 * type itself.
2389 */
2390 public Type classBound(Type t) {
2391 return classBound.visit(t);
2392 }
2393 // where
2394 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2396 public Type visitType(Type t, Void ignored) {
2397 return t;
2398 }
2400 @Override
2401 public Type visitClassType(ClassType t, Void ignored) {
2402 Type outer1 = classBound(t.getEnclosingType());
2403 if (outer1 != t.getEnclosingType())
2404 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
2405 else
2406 return t;
2407 }
2409 @Override
2410 public Type visitTypeVar(TypeVar t, Void ignored) {
2411 return classBound(supertype(t));
2412 }
2414 @Override
2415 public Type visitErrorType(ErrorType t, Void ignored) {
2416 return t;
2417 }
2418 };
2419 // </editor-fold>
2421 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
2422 /**
2423 * Returns true iff the first signature is a <em>sub
2424 * signature</em> of the other. This is <b>not</b> an equivalence
2425 * relation.
2426 *
2427 * @jls section 8.4.2.
2428 * @see #overrideEquivalent(Type t, Type s)
2429 * @param t first signature (possibly raw).
2430 * @param s second signature (could be subjected to erasure).
2431 * @return true if t is a sub signature of s.
2432 */
2433 public boolean isSubSignature(Type t, Type s) {
2434 return isSubSignature(t, s, true);
2435 }
2437 public boolean isSubSignature(Type t, Type s, boolean strict) {
2438 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2439 }
2441 /**
2442 * Returns true iff these signatures are related by <em>override
2443 * equivalence</em>. This is the natural extension of
2444 * isSubSignature to an equivalence relation.
2445 *
2446 * @jls section 8.4.2.
2447 * @see #isSubSignature(Type t, Type s)
2448 * @param t a signature (possible raw, could be subjected to
2449 * erasure).
2450 * @param s a signature (possible raw, could be subjected to
2451 * erasure).
2452 * @return true if either argument is a sub signature of the other.
2453 */
2454 public boolean overrideEquivalent(Type t, Type s) {
2455 return hasSameArgs(t, s) ||
2456 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2457 }
2459 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2460 for (Scope.Entry e = syms.objectType.tsym.members().lookup(msym.name) ; e.scope != null ; e = e.next()) {
2461 if (msym.overrides(e.sym, origin, Types.this, true)) {
2462 return true;
2463 }
2464 }
2465 return false;
2466 }
2468 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2469 class ImplementationCache {
2471 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
2472 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
2474 class Entry {
2475 final MethodSymbol cachedImpl;
2476 final Filter<Symbol> implFilter;
2477 final boolean checkResult;
2478 final int prevMark;
2480 public Entry(MethodSymbol cachedImpl,
2481 Filter<Symbol> scopeFilter,
2482 boolean checkResult,
2483 int prevMark) {
2484 this.cachedImpl = cachedImpl;
2485 this.implFilter = scopeFilter;
2486 this.checkResult = checkResult;
2487 this.prevMark = prevMark;
2488 }
2490 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
2491 return this.implFilter == scopeFilter &&
2492 this.checkResult == checkResult &&
2493 this.prevMark == mark;
2494 }
2495 }
2497 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2498 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2499 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2500 if (cache == null) {
2501 cache = new HashMap<TypeSymbol, Entry>();
2502 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2503 }
2504 Entry e = cache.get(origin);
2505 CompoundScope members = membersClosure(origin.type, true);
2506 if (e == null ||
2507 !e.matches(implFilter, checkResult, members.getMark())) {
2508 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2509 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2510 return impl;
2511 }
2512 else {
2513 return e.cachedImpl;
2514 }
2515 }
2517 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2518 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = supertype(t)) {
2519 while (t.tag == TYPEVAR)
2520 t = t.getUpperBound();
2521 TypeSymbol c = t.tsym;
2522 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2523 e.scope != null;
2524 e = e.next(implFilter)) {
2525 if (e.sym != null &&
2526 e.sym.overrides(ms, origin, Types.this, checkResult))
2527 return (MethodSymbol)e.sym;
2528 }
2529 }
2530 return null;
2531 }
2532 }
2534 private ImplementationCache implCache = new ImplementationCache();
2536 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2537 return implCache.get(ms, origin, checkResult, implFilter);
2538 }
2539 // </editor-fold>
2541 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2542 class MembersClosureCache extends SimpleVisitor<CompoundScope, Boolean> {
2544 private WeakHashMap<TypeSymbol, Entry> _map =
2545 new WeakHashMap<TypeSymbol, Entry>();
2547 class Entry {
2548 final boolean skipInterfaces;
2549 final CompoundScope compoundScope;
2551 public Entry(boolean skipInterfaces, CompoundScope compoundScope) {
2552 this.skipInterfaces = skipInterfaces;
2553 this.compoundScope = compoundScope;
2554 }
2556 boolean matches(boolean skipInterfaces) {
2557 return this.skipInterfaces == skipInterfaces;
2558 }
2559 }
2561 List<TypeSymbol> seenTypes = List.nil();
2563 /** members closure visitor methods **/
2565 public CompoundScope visitType(Type t, Boolean skipInterface) {
2566 return null;
2567 }
2569 @Override
2570 public CompoundScope visitClassType(ClassType t, Boolean skipInterface) {
2571 if (seenTypes.contains(t.tsym)) {
2572 //this is possible when an interface is implemented in multiple
2573 //superclasses, or when a classs hierarchy is circular - in such
2574 //cases we don't need to recurse (empty scope is returned)
2575 return new CompoundScope(t.tsym);
2576 }
2577 try {
2578 seenTypes = seenTypes.prepend(t.tsym);
2579 ClassSymbol csym = (ClassSymbol)t.tsym;
2580 Entry e = _map.get(csym);
2581 if (e == null || !e.matches(skipInterface)) {
2582 CompoundScope membersClosure = new CompoundScope(csym);
2583 if (!skipInterface) {
2584 for (Type i : interfaces(t)) {
2585 membersClosure.addSubScope(visit(i, skipInterface));
2586 }
2587 }
2588 membersClosure.addSubScope(visit(supertype(t), skipInterface));
2589 membersClosure.addSubScope(csym.members());
2590 e = new Entry(skipInterface, membersClosure);
2591 _map.put(csym, e);
2592 }
2593 return e.compoundScope;
2594 }
2595 finally {
2596 seenTypes = seenTypes.tail;
2597 }
2598 }
2600 @Override
2601 public CompoundScope visitTypeVar(TypeVar t, Boolean skipInterface) {
2602 return visit(t.getUpperBound(), skipInterface);
2603 }
2604 }
2606 private MembersClosureCache membersCache = new MembersClosureCache();
2608 public CompoundScope membersClosure(Type site, boolean skipInterface) {
2609 return membersCache.visit(site, skipInterface);
2610 }
2611 // </editor-fold>
2614 //where
2615 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
2616 Filter<Symbol> filter = new MethodFilter(ms, site);
2617 List<MethodSymbol> candidates = List.nil();
2618 for (Symbol s : membersClosure(site, false).getElements(filter)) {
2619 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
2620 return List.of((MethodSymbol)s);
2621 } else if (!candidates.contains(s)) {
2622 candidates = candidates.prepend((MethodSymbol)s);
2623 }
2624 }
2625 return prune(candidates);
2626 }
2628 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
2629 ListBuffer<MethodSymbol> methodsMin = ListBuffer.lb();
2630 for (MethodSymbol m1 : methods) {
2631 boolean isMin_m1 = true;
2632 for (MethodSymbol m2 : methods) {
2633 if (m1 == m2) continue;
2634 if (m2.owner != m1.owner &&
2635 asSuper(m2.owner.type, m1.owner) != null) {
2636 isMin_m1 = false;
2637 break;
2638 }
2639 }
2640 if (isMin_m1)
2641 methodsMin.append(m1);
2642 }
2643 return methodsMin.toList();
2644 }
2645 // where
2646 private class MethodFilter implements Filter<Symbol> {
2648 Symbol msym;
2649 Type site;
2651 MethodFilter(Symbol msym, Type site) {
2652 this.msym = msym;
2653 this.site = site;
2654 }
2656 public boolean accepts(Symbol s) {
2657 return s.kind == Kinds.MTH &&
2658 s.name == msym.name &&
2659 s.isInheritedIn(site.tsym, Types.this) &&
2660 overrideEquivalent(memberType(site, s), memberType(site, msym));
2661 }
2662 };
2663 // </editor-fold>
2665 /**
2666 * Does t have the same arguments as s? It is assumed that both
2667 * types are (possibly polymorphic) method types. Monomorphic
2668 * method types "have the same arguments", if their argument lists
2669 * are equal. Polymorphic method types "have the same arguments",
2670 * if they have the same arguments after renaming all type
2671 * variables of one to corresponding type variables in the other,
2672 * where correspondence is by position in the type parameter list.
2673 */
2674 public boolean hasSameArgs(Type t, Type s) {
2675 return hasSameArgs(t, s, true);
2676 }
2678 public boolean hasSameArgs(Type t, Type s, boolean strict) {
2679 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
2680 }
2682 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
2683 return hasSameArgs.visit(t, s);
2684 }
2685 // where
2686 private class HasSameArgs extends TypeRelation {
2688 boolean strict;
2690 public HasSameArgs(boolean strict) {
2691 this.strict = strict;
2692 }
2694 public Boolean visitType(Type t, Type s) {
2695 throw new AssertionError();
2696 }
2698 @Override
2699 public Boolean visitMethodType(MethodType t, Type s) {
2700 return s.tag == METHOD
2701 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2702 }
2704 @Override
2705 public Boolean visitForAll(ForAll t, Type s) {
2706 if (s.tag != FORALL)
2707 return strict ? false : visitMethodType(t.asMethodType(), s);
2709 ForAll forAll = (ForAll)s;
2710 return hasSameBounds(t, forAll)
2711 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2712 }
2714 @Override
2715 public Boolean visitErrorType(ErrorType t, Type s) {
2716 return false;
2717 }
2718 };
2720 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
2721 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
2723 // </editor-fold>
2725 // <editor-fold defaultstate="collapsed" desc="subst">
2726 public List<Type> subst(List<Type> ts,
2727 List<Type> from,
2728 List<Type> to) {
2729 return new Subst(from, to).subst(ts);
2730 }
2732 /**
2733 * Substitute all occurrences of a type in `from' with the
2734 * corresponding type in `to' in 't'. Match lists `from' and `to'
2735 * from the right: If lists have different length, discard leading
2736 * elements of the longer list.
2737 */
2738 public Type subst(Type t, List<Type> from, List<Type> to) {
2739 return new Subst(from, to).subst(t);
2740 }
2742 private class Subst extends UnaryVisitor<Type> {
2743 List<Type> from;
2744 List<Type> to;
2746 public Subst(List<Type> from, List<Type> to) {
2747 int fromLength = from.length();
2748 int toLength = to.length();
2749 while (fromLength > toLength) {
2750 fromLength--;
2751 from = from.tail;
2752 }
2753 while (fromLength < toLength) {
2754 toLength--;
2755 to = to.tail;
2756 }
2757 this.from = from;
2758 this.to = to;
2759 }
2761 Type subst(Type t) {
2762 if (from.tail == null)
2763 return t;
2764 else
2765 return visit(t);
2766 }
2768 List<Type> subst(List<Type> ts) {
2769 if (from.tail == null)
2770 return ts;
2771 boolean wild = false;
2772 if (ts.nonEmpty() && from.nonEmpty()) {
2773 Type head1 = subst(ts.head);
2774 List<Type> tail1 = subst(ts.tail);
2775 if (head1 != ts.head || tail1 != ts.tail)
2776 return tail1.prepend(head1);
2777 }
2778 return ts;
2779 }
2781 public Type visitType(Type t, Void ignored) {
2782 return t;
2783 }
2785 @Override
2786 public Type visitMethodType(MethodType t, Void ignored) {
2787 List<Type> argtypes = subst(t.argtypes);
2788 Type restype = subst(t.restype);
2789 List<Type> thrown = subst(t.thrown);
2790 if (argtypes == t.argtypes &&
2791 restype == t.restype &&
2792 thrown == t.thrown)
2793 return t;
2794 else
2795 return new MethodType(argtypes, restype, thrown, t.tsym);
2796 }
2798 @Override
2799 public Type visitTypeVar(TypeVar t, Void ignored) {
2800 for (List<Type> from = this.from, to = this.to;
2801 from.nonEmpty();
2802 from = from.tail, to = to.tail) {
2803 if (t == from.head) {
2804 return to.head.withTypeVar(t);
2805 }
2806 }
2807 return t;
2808 }
2810 @Override
2811 public Type visitClassType(ClassType t, Void ignored) {
2812 if (!t.isCompound()) {
2813 List<Type> typarams = t.getTypeArguments();
2814 List<Type> typarams1 = subst(typarams);
2815 Type outer = t.getEnclosingType();
2816 Type outer1 = subst(outer);
2817 if (typarams1 == typarams && outer1 == outer)
2818 return t;
2819 else
2820 return new ClassType(outer1, typarams1, t.tsym);
2821 } else {
2822 Type st = subst(supertype(t));
2823 List<Type> is = upperBounds(subst(interfaces(t)));
2824 if (st == supertype(t) && is == interfaces(t))
2825 return t;
2826 else
2827 return makeCompoundType(is.prepend(st));
2828 }
2829 }
2831 @Override
2832 public Type visitWildcardType(WildcardType t, Void ignored) {
2833 Type bound = t.type;
2834 if (t.kind != BoundKind.UNBOUND)
2835 bound = subst(bound);
2836 if (bound == t.type) {
2837 return t;
2838 } else {
2839 if (t.isExtendsBound() && bound.isExtendsBound())
2840 bound = upperBound(bound);
2841 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2842 }
2843 }
2845 @Override
2846 public Type visitArrayType(ArrayType t, Void ignored) {
2847 Type elemtype = subst(t.elemtype);
2848 if (elemtype == t.elemtype)
2849 return t;
2850 else
2851 return new ArrayType(upperBound(elemtype), t.tsym);
2852 }
2854 @Override
2855 public Type visitForAll(ForAll t, Void ignored) {
2856 if (Type.containsAny(to, t.tvars)) {
2857 //perform alpha-renaming of free-variables in 't'
2858 //if 'to' types contain variables that are free in 't'
2859 List<Type> freevars = newInstances(t.tvars);
2860 t = new ForAll(freevars,
2861 Types.this.subst(t.qtype, t.tvars, freevars));
2862 }
2863 List<Type> tvars1 = substBounds(t.tvars, from, to);
2864 Type qtype1 = subst(t.qtype);
2865 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2866 return t;
2867 } else if (tvars1 == t.tvars) {
2868 return new ForAll(tvars1, qtype1);
2869 } else {
2870 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2871 }
2872 }
2874 @Override
2875 public Type visitErrorType(ErrorType t, Void ignored) {
2876 return t;
2877 }
2878 }
2880 public List<Type> substBounds(List<Type> tvars,
2881 List<Type> from,
2882 List<Type> to) {
2883 if (tvars.isEmpty())
2884 return tvars;
2885 ListBuffer<Type> newBoundsBuf = lb();
2886 boolean changed = false;
2887 // calculate new bounds
2888 for (Type t : tvars) {
2889 TypeVar tv = (TypeVar) t;
2890 Type bound = subst(tv.bound, from, to);
2891 if (bound != tv.bound)
2892 changed = true;
2893 newBoundsBuf.append(bound);
2894 }
2895 if (!changed)
2896 return tvars;
2897 ListBuffer<Type> newTvars = lb();
2898 // create new type variables without bounds
2899 for (Type t : tvars) {
2900 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2901 }
2902 // the new bounds should use the new type variables in place
2903 // of the old
2904 List<Type> newBounds = newBoundsBuf.toList();
2905 from = tvars;
2906 to = newTvars.toList();
2907 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2908 newBounds.head = subst(newBounds.head, from, to);
2909 }
2910 newBounds = newBoundsBuf.toList();
2911 // set the bounds of new type variables to the new bounds
2912 for (Type t : newTvars.toList()) {
2913 TypeVar tv = (TypeVar) t;
2914 tv.bound = newBounds.head;
2915 newBounds = newBounds.tail;
2916 }
2917 return newTvars.toList();
2918 }
2920 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2921 Type bound1 = subst(t.bound, from, to);
2922 if (bound1 == t.bound)
2923 return t;
2924 else {
2925 // create new type variable without bounds
2926 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2927 // the new bound should use the new type variable in place
2928 // of the old
2929 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2930 return tv;
2931 }
2932 }
2933 // </editor-fold>
2935 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2936 /**
2937 * Does t have the same bounds for quantified variables as s?
2938 */
2939 boolean hasSameBounds(ForAll t, ForAll s) {
2940 List<Type> l1 = t.tvars;
2941 List<Type> l2 = s.tvars;
2942 while (l1.nonEmpty() && l2.nonEmpty() &&
2943 isSameType(l1.head.getUpperBound(),
2944 subst(l2.head.getUpperBound(),
2945 s.tvars,
2946 t.tvars))) {
2947 l1 = l1.tail;
2948 l2 = l2.tail;
2949 }
2950 return l1.isEmpty() && l2.isEmpty();
2951 }
2952 // </editor-fold>
2954 // <editor-fold defaultstate="collapsed" desc="newInstances">
2955 /** Create new vector of type variables from list of variables
2956 * changing all recursive bounds from old to new list.
2957 */
2958 public List<Type> newInstances(List<Type> tvars) {
2959 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2960 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2961 TypeVar tv = (TypeVar) l.head;
2962 tv.bound = subst(tv.bound, tvars, tvars1);
2963 }
2964 return tvars1;
2965 }
2966 private static final Mapping newInstanceFun = new Mapping("newInstanceFun") {
2967 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2968 };
2969 // </editor-fold>
2971 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
2972 return original.accept(methodWithParameters, newParams);
2973 }
2974 // where
2975 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
2976 public Type visitType(Type t, List<Type> newParams) {
2977 throw new IllegalArgumentException("Not a method type: " + t);
2978 }
2979 public Type visitMethodType(MethodType t, List<Type> newParams) {
2980 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
2981 }
2982 public Type visitForAll(ForAll t, List<Type> newParams) {
2983 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
2984 }
2985 };
2987 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
2988 return original.accept(methodWithThrown, newThrown);
2989 }
2990 // where
2991 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
2992 public Type visitType(Type t, List<Type> newThrown) {
2993 throw new IllegalArgumentException("Not a method type: " + t);
2994 }
2995 public Type visitMethodType(MethodType t, List<Type> newThrown) {
2996 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
2997 }
2998 public Type visitForAll(ForAll t, List<Type> newThrown) {
2999 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
3000 }
3001 };
3003 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
3004 return original.accept(methodWithReturn, newReturn);
3005 }
3006 // where
3007 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
3008 public Type visitType(Type t, Type newReturn) {
3009 throw new IllegalArgumentException("Not a method type: " + t);
3010 }
3011 public Type visitMethodType(MethodType t, Type newReturn) {
3012 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym);
3013 }
3014 public Type visitForAll(ForAll t, Type newReturn) {
3015 return new ForAll(t.tvars, t.qtype.accept(this, newReturn));
3016 }
3017 };
3019 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3020 public Type createErrorType(Type originalType) {
3021 return new ErrorType(originalType, syms.errSymbol);
3022 }
3024 public Type createErrorType(ClassSymbol c, Type originalType) {
3025 return new ErrorType(c, originalType);
3026 }
3028 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3029 return new ErrorType(name, container, originalType);
3030 }
3031 // </editor-fold>
3033 // <editor-fold defaultstate="collapsed" desc="rank">
3034 /**
3035 * The rank of a class is the length of the longest path between
3036 * the class and java.lang.Object in the class inheritance
3037 * graph. Undefined for all but reference types.
3038 */
3039 public int rank(Type t) {
3040 t = t.unannotatedType();
3041 switch(t.tag) {
3042 case CLASS: {
3043 ClassType cls = (ClassType)t;
3044 if (cls.rank_field < 0) {
3045 Name fullname = cls.tsym.getQualifiedName();
3046 if (fullname == names.java_lang_Object)
3047 cls.rank_field = 0;
3048 else {
3049 int r = rank(supertype(cls));
3050 for (List<Type> l = interfaces(cls);
3051 l.nonEmpty();
3052 l = l.tail) {
3053 if (rank(l.head) > r)
3054 r = rank(l.head);
3055 }
3056 cls.rank_field = r + 1;
3057 }
3058 }
3059 return cls.rank_field;
3060 }
3061 case TYPEVAR: {
3062 TypeVar tvar = (TypeVar)t;
3063 if (tvar.rank_field < 0) {
3064 int r = rank(supertype(tvar));
3065 for (List<Type> l = interfaces(tvar);
3066 l.nonEmpty();
3067 l = l.tail) {
3068 if (rank(l.head) > r) r = rank(l.head);
3069 }
3070 tvar.rank_field = r + 1;
3071 }
3072 return tvar.rank_field;
3073 }
3074 case ERROR:
3075 return 0;
3076 default:
3077 throw new AssertionError();
3078 }
3079 }
3080 // </editor-fold>
3082 /**
3083 * Helper method for generating a string representation of a given type
3084 * accordingly to a given locale
3085 */
3086 public String toString(Type t, Locale locale) {
3087 return Printer.createStandardPrinter(messages).visit(t, locale);
3088 }
3090 /**
3091 * Helper method for generating a string representation of a given type
3092 * accordingly to a given locale
3093 */
3094 public String toString(Symbol t, Locale locale) {
3095 return Printer.createStandardPrinter(messages).visit(t, locale);
3096 }
3098 // <editor-fold defaultstate="collapsed" desc="toString">
3099 /**
3100 * This toString is slightly more descriptive than the one on Type.
3101 *
3102 * @deprecated Types.toString(Type t, Locale l) provides better support
3103 * for localization
3104 */
3105 @Deprecated
3106 public String toString(Type t) {
3107 if (t.tag == FORALL) {
3108 ForAll forAll = (ForAll)t;
3109 return typaramsString(forAll.tvars) + forAll.qtype;
3110 }
3111 return "" + t;
3112 }
3113 // where
3114 private String typaramsString(List<Type> tvars) {
3115 StringBuilder s = new StringBuilder();
3116 s.append('<');
3117 boolean first = true;
3118 for (Type t : tvars) {
3119 if (!first) s.append(", ");
3120 first = false;
3121 appendTyparamString(((TypeVar)t), s);
3122 }
3123 s.append('>');
3124 return s.toString();
3125 }
3126 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3127 buf.append(t);
3128 if (t.bound == null ||
3129 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
3130 return;
3131 buf.append(" extends "); // Java syntax; no need for i18n
3132 Type bound = t.bound;
3133 if (!bound.isCompound()) {
3134 buf.append(bound);
3135 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3136 buf.append(supertype(t));
3137 for (Type intf : interfaces(t)) {
3138 buf.append('&');
3139 buf.append(intf);
3140 }
3141 } else {
3142 // No superclass was given in bounds.
3143 // In this case, supertype is Object, erasure is first interface.
3144 boolean first = true;
3145 for (Type intf : interfaces(t)) {
3146 if (!first) buf.append('&');
3147 first = false;
3148 buf.append(intf);
3149 }
3150 }
3151 }
3152 // </editor-fold>
3154 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3155 /**
3156 * A cache for closures.
3157 *
3158 * <p>A closure is a list of all the supertypes and interfaces of
3159 * a class or interface type, ordered by ClassSymbol.precedes
3160 * (that is, subclasses come first, arbitrary but fixed
3161 * otherwise).
3162 */
3163 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
3165 /**
3166 * Returns the closure of a class or interface type.
3167 */
3168 public List<Type> closure(Type t) {
3169 List<Type> cl = closureCache.get(t);
3170 if (cl == null) {
3171 Type st = supertype(t);
3172 if (!t.isCompound()) {
3173 if (st.tag == CLASS) {
3174 cl = insert(closure(st), t);
3175 } else if (st.tag == TYPEVAR) {
3176 cl = closure(st).prepend(t);
3177 } else {
3178 cl = List.of(t);
3179 }
3180 } else {
3181 cl = closure(supertype(t));
3182 }
3183 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3184 cl = union(cl, closure(l.head));
3185 closureCache.put(t, cl);
3186 }
3187 return cl;
3188 }
3190 /**
3191 * Insert a type in a closure
3192 */
3193 public List<Type> insert(List<Type> cl, Type t) {
3194 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
3195 return cl.prepend(t);
3196 } else if (cl.head.tsym.precedes(t.tsym, this)) {
3197 return insert(cl.tail, t).prepend(cl.head);
3198 } else {
3199 return cl;
3200 }
3201 }
3203 /**
3204 * Form the union of two closures
3205 */
3206 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3207 if (cl1.isEmpty()) {
3208 return cl2;
3209 } else if (cl2.isEmpty()) {
3210 return cl1;
3211 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
3212 return union(cl1.tail, cl2).prepend(cl1.head);
3213 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3214 return union(cl1, cl2.tail).prepend(cl2.head);
3215 } else {
3216 return union(cl1.tail, cl2.tail).prepend(cl1.head);
3217 }
3218 }
3220 /**
3221 * Intersect two closures
3222 */
3223 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3224 if (cl1 == cl2)
3225 return cl1;
3226 if (cl1.isEmpty() || cl2.isEmpty())
3227 return List.nil();
3228 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3229 return intersect(cl1.tail, cl2);
3230 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3231 return intersect(cl1, cl2.tail);
3232 if (isSameType(cl1.head, cl2.head))
3233 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3234 if (cl1.head.tsym == cl2.head.tsym &&
3235 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
3236 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3237 Type merge = merge(cl1.head,cl2.head);
3238 return intersect(cl1.tail, cl2.tail).prepend(merge);
3239 }
3240 if (cl1.head.isRaw() || cl2.head.isRaw())
3241 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3242 }
3243 return intersect(cl1.tail, cl2.tail);
3244 }
3245 // where
3246 class TypePair {
3247 final Type t1;
3248 final Type t2;
3249 TypePair(Type t1, Type t2) {
3250 this.t1 = t1;
3251 this.t2 = t2;
3252 }
3253 @Override
3254 public int hashCode() {
3255 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3256 }
3257 @Override
3258 public boolean equals(Object obj) {
3259 if (!(obj instanceof TypePair))
3260 return false;
3261 TypePair typePair = (TypePair)obj;
3262 return isSameType(t1, typePair.t1)
3263 && isSameType(t2, typePair.t2);
3264 }
3265 }
3266 Set<TypePair> mergeCache = new HashSet<TypePair>();
3267 private Type merge(Type c1, Type c2) {
3268 ClassType class1 = (ClassType) c1;
3269 List<Type> act1 = class1.getTypeArguments();
3270 ClassType class2 = (ClassType) c2;
3271 List<Type> act2 = class2.getTypeArguments();
3272 ListBuffer<Type> merged = new ListBuffer<Type>();
3273 List<Type> typarams = class1.tsym.type.getTypeArguments();
3275 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3276 if (containsType(act1.head, act2.head)) {
3277 merged.append(act1.head);
3278 } else if (containsType(act2.head, act1.head)) {
3279 merged.append(act2.head);
3280 } else {
3281 TypePair pair = new TypePair(c1, c2);
3282 Type m;
3283 if (mergeCache.add(pair)) {
3284 m = new WildcardType(lub(upperBound(act1.head),
3285 upperBound(act2.head)),
3286 BoundKind.EXTENDS,
3287 syms.boundClass);
3288 mergeCache.remove(pair);
3289 } else {
3290 m = new WildcardType(syms.objectType,
3291 BoundKind.UNBOUND,
3292 syms.boundClass);
3293 }
3294 merged.append(m.withTypeVar(typarams.head));
3295 }
3296 act1 = act1.tail;
3297 act2 = act2.tail;
3298 typarams = typarams.tail;
3299 }
3300 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3301 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
3302 }
3304 /**
3305 * Return the minimum type of a closure, a compound type if no
3306 * unique minimum exists.
3307 */
3308 private Type compoundMin(List<Type> cl) {
3309 if (cl.isEmpty()) return syms.objectType;
3310 List<Type> compound = closureMin(cl);
3311 if (compound.isEmpty())
3312 return null;
3313 else if (compound.tail.isEmpty())
3314 return compound.head;
3315 else
3316 return makeCompoundType(compound);
3317 }
3319 /**
3320 * Return the minimum types of a closure, suitable for computing
3321 * compoundMin or glb.
3322 */
3323 private List<Type> closureMin(List<Type> cl) {
3324 ListBuffer<Type> classes = lb();
3325 ListBuffer<Type> interfaces = lb();
3326 while (!cl.isEmpty()) {
3327 Type current = cl.head;
3328 if (current.isInterface())
3329 interfaces.append(current);
3330 else
3331 classes.append(current);
3332 ListBuffer<Type> candidates = lb();
3333 for (Type t : cl.tail) {
3334 if (!isSubtypeNoCapture(current, t))
3335 candidates.append(t);
3336 }
3337 cl = candidates.toList();
3338 }
3339 return classes.appendList(interfaces).toList();
3340 }
3342 /**
3343 * Return the least upper bound of pair of types. if the lub does
3344 * not exist return null.
3345 */
3346 public Type lub(Type t1, Type t2) {
3347 return lub(List.of(t1, t2));
3348 }
3350 /**
3351 * Return the least upper bound (lub) of set of types. If the lub
3352 * does not exist return the type of null (bottom).
3353 */
3354 public Type lub(List<Type> ts) {
3355 final int ARRAY_BOUND = 1;
3356 final int CLASS_BOUND = 2;
3357 int boundkind = 0;
3358 for (Type t : ts) {
3359 switch (t.tag) {
3360 case CLASS:
3361 boundkind |= CLASS_BOUND;
3362 break;
3363 case ARRAY:
3364 boundkind |= ARRAY_BOUND;
3365 break;
3366 case TYPEVAR:
3367 do {
3368 t = t.getUpperBound();
3369 } while (t.tag == TYPEVAR);
3370 if (t.tag == ARRAY) {
3371 boundkind |= ARRAY_BOUND;
3372 } else {
3373 boundkind |= CLASS_BOUND;
3374 }
3375 break;
3376 default:
3377 if (t.isPrimitive())
3378 return syms.errType;
3379 }
3380 }
3381 switch (boundkind) {
3382 case 0:
3383 return syms.botType;
3385 case ARRAY_BOUND:
3386 // calculate lub(A[], B[])
3387 List<Type> elements = Type.map(ts, elemTypeFun);
3388 for (Type t : elements) {
3389 if (t.isPrimitive()) {
3390 // if a primitive type is found, then return
3391 // arraySuperType unless all the types are the
3392 // same
3393 Type first = ts.head;
3394 for (Type s : ts.tail) {
3395 if (!isSameType(first, s)) {
3396 // lub(int[], B[]) is Cloneable & Serializable
3397 return arraySuperType();
3398 }
3399 }
3400 // all the array types are the same, return one
3401 // lub(int[], int[]) is int[]
3402 return first;
3403 }
3404 }
3405 // lub(A[], B[]) is lub(A, B)[]
3406 return new ArrayType(lub(elements), syms.arrayClass);
3408 case CLASS_BOUND:
3409 // calculate lub(A, B)
3410 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
3411 ts = ts.tail;
3412 Assert.check(!ts.isEmpty());
3413 //step 1 - compute erased candidate set (EC)
3414 List<Type> cl = erasedSupertypes(ts.head);
3415 for (Type t : ts.tail) {
3416 if (t.tag == CLASS || t.tag == TYPEVAR)
3417 cl = intersect(cl, erasedSupertypes(t));
3418 }
3419 //step 2 - compute minimal erased candidate set (MEC)
3420 List<Type> mec = closureMin(cl);
3421 //step 3 - for each element G in MEC, compute lci(Inv(G))
3422 List<Type> candidates = List.nil();
3423 for (Type erasedSupertype : mec) {
3424 List<Type> lci = List.of(asSuper(ts.head, erasedSupertype.tsym));
3425 for (Type t : ts) {
3426 lci = intersect(lci, List.of(asSuper(t, erasedSupertype.tsym)));
3427 }
3428 candidates = candidates.appendList(lci);
3429 }
3430 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
3431 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
3432 return compoundMin(candidates);
3434 default:
3435 // calculate lub(A, B[])
3436 List<Type> classes = List.of(arraySuperType());
3437 for (Type t : ts) {
3438 if (t.tag != ARRAY) // Filter out any arrays
3439 classes = classes.prepend(t);
3440 }
3441 // lub(A, B[]) is lub(A, arraySuperType)
3442 return lub(classes);
3443 }
3444 }
3445 // where
3446 List<Type> erasedSupertypes(Type t) {
3447 ListBuffer<Type> buf = lb();
3448 for (Type sup : closure(t)) {
3449 if (sup.tag == TYPEVAR) {
3450 buf.append(sup);
3451 } else {
3452 buf.append(erasure(sup));
3453 }
3454 }
3455 return buf.toList();
3456 }
3458 private Type arraySuperType = null;
3459 private Type arraySuperType() {
3460 // initialized lazily to avoid problems during compiler startup
3461 if (arraySuperType == null) {
3462 synchronized (this) {
3463 if (arraySuperType == null) {
3464 // JLS 10.8: all arrays implement Cloneable and Serializable.
3465 arraySuperType = makeCompoundType(List.of(syms.serializableType,
3466 syms.cloneableType), true);
3467 }
3468 }
3469 }
3470 return arraySuperType;
3471 }
3472 // </editor-fold>
3474 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
3475 public Type glb(List<Type> ts) {
3476 Type t1 = ts.head;
3477 for (Type t2 : ts.tail) {
3478 if (t1.isErroneous())
3479 return t1;
3480 t1 = glb(t1, t2);
3481 }
3482 return t1;
3483 }
3484 //where
3485 public Type glb(Type t, Type s) {
3486 if (s == null)
3487 return t;
3488 else if (t.isPrimitive() || s.isPrimitive())
3489 return syms.errType;
3490 else if (isSubtypeNoCapture(t, s))
3491 return t;
3492 else if (isSubtypeNoCapture(s, t))
3493 return s;
3495 List<Type> closure = union(closure(t), closure(s));
3496 List<Type> bounds = closureMin(closure);
3498 if (bounds.isEmpty()) { // length == 0
3499 return syms.objectType;
3500 } else if (bounds.tail.isEmpty()) { // length == 1
3501 return bounds.head;
3502 } else { // length > 1
3503 int classCount = 0;
3504 for (Type bound : bounds)
3505 if (!bound.isInterface())
3506 classCount++;
3507 if (classCount > 1)
3508 return createErrorType(t);
3509 }
3510 return makeCompoundType(bounds);
3511 }
3512 // </editor-fold>
3514 // <editor-fold defaultstate="collapsed" desc="hashCode">
3515 /**
3516 * Compute a hash code on a type.
3517 */
3518 public int hashCode(Type t) {
3519 return hashCode.visit(t);
3520 }
3521 // where
3522 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
3524 public Integer visitType(Type t, Void ignored) {
3525 return t.tag.ordinal();
3526 }
3528 @Override
3529 public Integer visitClassType(ClassType t, Void ignored) {
3530 int result = visit(t.getEnclosingType());
3531 result *= 127;
3532 result += t.tsym.flatName().hashCode();
3533 for (Type s : t.getTypeArguments()) {
3534 result *= 127;
3535 result += visit(s);
3536 }
3537 return result;
3538 }
3540 @Override
3541 public Integer visitMethodType(MethodType t, Void ignored) {
3542 int h = METHOD.ordinal();
3543 for (List<Type> thisargs = t.argtypes;
3544 thisargs.tail != null;
3545 thisargs = thisargs.tail)
3546 h = (h << 5) + visit(thisargs.head);
3547 return (h << 5) + visit(t.restype);
3548 }
3550 @Override
3551 public Integer visitWildcardType(WildcardType t, Void ignored) {
3552 int result = t.kind.hashCode();
3553 if (t.type != null) {
3554 result *= 127;
3555 result += visit(t.type);
3556 }
3557 return result;
3558 }
3560 @Override
3561 public Integer visitArrayType(ArrayType t, Void ignored) {
3562 return visit(t.elemtype) + 12;
3563 }
3565 @Override
3566 public Integer visitTypeVar(TypeVar t, Void ignored) {
3567 return System.identityHashCode(t.tsym);
3568 }
3570 @Override
3571 public Integer visitUndetVar(UndetVar t, Void ignored) {
3572 return System.identityHashCode(t);
3573 }
3575 @Override
3576 public Integer visitErrorType(ErrorType t, Void ignored) {
3577 return 0;
3578 }
3579 };
3580 // </editor-fold>
3582 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
3583 /**
3584 * Does t have a result that is a subtype of the result type of s,
3585 * suitable for covariant returns? It is assumed that both types
3586 * are (possibly polymorphic) method types. Monomorphic method
3587 * types are handled in the obvious way. Polymorphic method types
3588 * require renaming all type variables of one to corresponding
3589 * type variables in the other, where correspondence is by
3590 * position in the type parameter list. */
3591 public boolean resultSubtype(Type t, Type s, Warner warner) {
3592 List<Type> tvars = t.getTypeArguments();
3593 List<Type> svars = s.getTypeArguments();
3594 Type tres = t.getReturnType();
3595 Type sres = subst(s.getReturnType(), svars, tvars);
3596 return covariantReturnType(tres, sres, warner);
3597 }
3599 /**
3600 * Return-Type-Substitutable.
3601 * @jls section 8.4.5
3602 */
3603 public boolean returnTypeSubstitutable(Type r1, Type r2) {
3604 if (hasSameArgs(r1, r2))
3605 return resultSubtype(r1, r2, noWarnings);
3606 else
3607 return covariantReturnType(r1.getReturnType(),
3608 erasure(r2.getReturnType()),
3609 noWarnings);
3610 }
3612 public boolean returnTypeSubstitutable(Type r1,
3613 Type r2, Type r2res,
3614 Warner warner) {
3615 if (isSameType(r1.getReturnType(), r2res))
3616 return true;
3617 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
3618 return false;
3620 if (hasSameArgs(r1, r2))
3621 return covariantReturnType(r1.getReturnType(), r2res, warner);
3622 if (!allowCovariantReturns)
3623 return false;
3624 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
3625 return true;
3626 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
3627 return false;
3628 warner.warn(LintCategory.UNCHECKED);
3629 return true;
3630 }
3632 /**
3633 * Is t an appropriate return type in an overrider for a
3634 * method that returns s?
3635 */
3636 public boolean covariantReturnType(Type t, Type s, Warner warner) {
3637 return
3638 isSameType(t, s) ||
3639 allowCovariantReturns &&
3640 !t.isPrimitive() &&
3641 !s.isPrimitive() &&
3642 isAssignable(t, s, warner);
3643 }
3644 // </editor-fold>
3646 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
3647 /**
3648 * Return the class that boxes the given primitive.
3649 */
3650 public ClassSymbol boxedClass(Type t) {
3651 return reader.enterClass(syms.boxedName[t.tag.ordinal()]);
3652 }
3654 /**
3655 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
3656 */
3657 public Type boxedTypeOrType(Type t) {
3658 return t.isPrimitive() ?
3659 boxedClass(t).type :
3660 t;
3661 }
3663 /**
3664 * Return the primitive type corresponding to a boxed type.
3665 */
3666 public Type unboxedType(Type t) {
3667 if (allowBoxing) {
3668 for (int i=0; i<syms.boxedName.length; i++) {
3669 Name box = syms.boxedName[i];
3670 if (box != null &&
3671 asSuper(t, reader.enterClass(box)) != null)
3672 return syms.typeOfTag[i];
3673 }
3674 }
3675 return Type.noType;
3676 }
3678 /**
3679 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
3680 */
3681 public Type unboxedTypeOrType(Type t) {
3682 Type unboxedType = unboxedType(t);
3683 return unboxedType.tag == NONE ? t : unboxedType;
3684 }
3685 // </editor-fold>
3687 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3688 /*
3689 * JLS 5.1.10 Capture Conversion:
3690 *
3691 * Let G name a generic type declaration with n formal type
3692 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3693 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3694 * where, for 1 <= i <= n:
3695 *
3696 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3697 * Si is a fresh type variable whose upper bound is
3698 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3699 * type.
3700 *
3701 * + If Ti is a wildcard type argument of the form ? extends Bi,
3702 * then Si is a fresh type variable whose upper bound is
3703 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3704 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3705 * a compile-time error if for any two classes (not interfaces)
3706 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3707 *
3708 * + If Ti is a wildcard type argument of the form ? super Bi,
3709 * then Si is a fresh type variable whose upper bound is
3710 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3711 *
3712 * + Otherwise, Si = Ti.
3713 *
3714 * Capture conversion on any type other than a parameterized type
3715 * (4.5) acts as an identity conversion (5.1.1). Capture
3716 * conversions never require a special action at run time and
3717 * therefore never throw an exception at run time.
3718 *
3719 * Capture conversion is not applied recursively.
3720 */
3721 /**
3722 * Capture conversion as specified by the JLS.
3723 */
3725 public List<Type> capture(List<Type> ts) {
3726 List<Type> buf = List.nil();
3727 for (Type t : ts) {
3728 buf = buf.prepend(capture(t));
3729 }
3730 return buf.reverse();
3731 }
3732 public Type capture(Type t) {
3733 if (t.tag != CLASS)
3734 return t;
3735 if (t.getEnclosingType() != Type.noType) {
3736 Type capturedEncl = capture(t.getEnclosingType());
3737 if (capturedEncl != t.getEnclosingType()) {
3738 Type type1 = memberType(capturedEncl, t.tsym);
3739 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3740 }
3741 }
3742 t = t.unannotatedType();
3743 ClassType cls = (ClassType)t;
3744 if (cls.isRaw() || !cls.isParameterized())
3745 return cls;
3747 ClassType G = (ClassType)cls.asElement().asType();
3748 List<Type> A = G.getTypeArguments();
3749 List<Type> T = cls.getTypeArguments();
3750 List<Type> S = freshTypeVariables(T);
3752 List<Type> currentA = A;
3753 List<Type> currentT = T;
3754 List<Type> currentS = S;
3755 boolean captured = false;
3756 while (!currentA.isEmpty() &&
3757 !currentT.isEmpty() &&
3758 !currentS.isEmpty()) {
3759 if (currentS.head != currentT.head) {
3760 captured = true;
3761 WildcardType Ti = (WildcardType)currentT.head;
3762 Type Ui = currentA.head.getUpperBound();
3763 CapturedType Si = (CapturedType)currentS.head;
3764 if (Ui == null)
3765 Ui = syms.objectType;
3766 switch (Ti.kind) {
3767 case UNBOUND:
3768 Si.bound = subst(Ui, A, S);
3769 Si.lower = syms.botType;
3770 break;
3771 case EXTENDS:
3772 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3773 Si.lower = syms.botType;
3774 break;
3775 case SUPER:
3776 Si.bound = subst(Ui, A, S);
3777 Si.lower = Ti.getSuperBound();
3778 break;
3779 }
3780 if (Si.bound == Si.lower)
3781 currentS.head = Si.bound;
3782 }
3783 currentA = currentA.tail;
3784 currentT = currentT.tail;
3785 currentS = currentS.tail;
3786 }
3787 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3788 return erasure(t); // some "rare" type involved
3790 if (captured)
3791 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3792 else
3793 return t;
3794 }
3795 // where
3796 public List<Type> freshTypeVariables(List<Type> types) {
3797 ListBuffer<Type> result = lb();
3798 for (Type t : types) {
3799 if (t.tag == WILDCARD) {
3800 Type bound = ((WildcardType)t).getExtendsBound();
3801 if (bound == null)
3802 bound = syms.objectType;
3803 result.append(new CapturedType(capturedName,
3804 syms.noSymbol,
3805 bound,
3806 syms.botType,
3807 (WildcardType)t));
3808 } else {
3809 result.append(t);
3810 }
3811 }
3812 return result.toList();
3813 }
3814 // </editor-fold>
3816 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3817 private List<Type> upperBounds(List<Type> ss) {
3818 if (ss.isEmpty()) return ss;
3819 Type head = upperBound(ss.head);
3820 List<Type> tail = upperBounds(ss.tail);
3821 if (head != ss.head || tail != ss.tail)
3822 return tail.prepend(head);
3823 else
3824 return ss;
3825 }
3827 private boolean sideCast(Type from, Type to, Warner warn) {
3828 // We are casting from type $from$ to type $to$, which are
3829 // non-final unrelated types. This method
3830 // tries to reject a cast by transferring type parameters
3831 // from $to$ to $from$ by common superinterfaces.
3832 boolean reverse = false;
3833 Type target = to;
3834 if ((to.tsym.flags() & INTERFACE) == 0) {
3835 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3836 reverse = true;
3837 to = from;
3838 from = target;
3839 }
3840 List<Type> commonSupers = superClosure(to, erasure(from));
3841 boolean giveWarning = commonSupers.isEmpty();
3842 // The arguments to the supers could be unified here to
3843 // get a more accurate analysis
3844 while (commonSupers.nonEmpty()) {
3845 Type t1 = asSuper(from, commonSupers.head.tsym);
3846 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3847 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3848 return false;
3849 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3850 commonSupers = commonSupers.tail;
3851 }
3852 if (giveWarning && !isReifiable(reverse ? from : to))
3853 warn.warn(LintCategory.UNCHECKED);
3854 if (!allowCovariantReturns)
3855 // reject if there is a common method signature with
3856 // incompatible return types.
3857 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3858 return true;
3859 }
3861 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3862 // We are casting from type $from$ to type $to$, which are
3863 // unrelated types one of which is final and the other of
3864 // which is an interface. This method
3865 // tries to reject a cast by transferring type parameters
3866 // from the final class to the interface.
3867 boolean reverse = false;
3868 Type target = to;
3869 if ((to.tsym.flags() & INTERFACE) == 0) {
3870 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3871 reverse = true;
3872 to = from;
3873 from = target;
3874 }
3875 Assert.check((from.tsym.flags() & FINAL) != 0);
3876 Type t1 = asSuper(from, to.tsym);
3877 if (t1 == null) return false;
3878 Type t2 = to;
3879 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3880 return false;
3881 if (!allowCovariantReturns)
3882 // reject if there is a common method signature with
3883 // incompatible return types.
3884 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3885 if (!isReifiable(target) &&
3886 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3887 warn.warn(LintCategory.UNCHECKED);
3888 return true;
3889 }
3891 private boolean giveWarning(Type from, Type to) {
3892 Type subFrom = asSub(from, to.tsym);
3893 return to.isParameterized() &&
3894 (!(isUnbounded(to) ||
3895 isSubtype(from, to) ||
3896 ((subFrom != null) && containsType(to.allparams(), subFrom.allparams()))));
3897 }
3899 private List<Type> superClosure(Type t, Type s) {
3900 List<Type> cl = List.nil();
3901 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3902 if (isSubtype(s, erasure(l.head))) {
3903 cl = insert(cl, l.head);
3904 } else {
3905 cl = union(cl, superClosure(l.head, s));
3906 }
3907 }
3908 return cl;
3909 }
3911 private boolean containsTypeEquivalent(Type t, Type s) {
3912 return
3913 isSameType(t, s) || // shortcut
3914 containsType(t, s) && containsType(s, t);
3915 }
3917 // <editor-fold defaultstate="collapsed" desc="adapt">
3918 /**
3919 * Adapt a type by computing a substitution which maps a source
3920 * type to a target type.
3921 *
3922 * @param source the source type
3923 * @param target the target type
3924 * @param from the type variables of the computed substitution
3925 * @param to the types of the computed substitution.
3926 */
3927 public void adapt(Type source,
3928 Type target,
3929 ListBuffer<Type> from,
3930 ListBuffer<Type> to) throws AdaptFailure {
3931 new Adapter(from, to).adapt(source, target);
3932 }
3934 class Adapter extends SimpleVisitor<Void, Type> {
3936 ListBuffer<Type> from;
3937 ListBuffer<Type> to;
3938 Map<Symbol,Type> mapping;
3940 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3941 this.from = from;
3942 this.to = to;
3943 mapping = new HashMap<Symbol,Type>();
3944 }
3946 public void adapt(Type source, Type target) throws AdaptFailure {
3947 visit(source, target);
3948 List<Type> fromList = from.toList();
3949 List<Type> toList = to.toList();
3950 while (!fromList.isEmpty()) {
3951 Type val = mapping.get(fromList.head.tsym);
3952 if (toList.head != val)
3953 toList.head = val;
3954 fromList = fromList.tail;
3955 toList = toList.tail;
3956 }
3957 }
3959 @Override
3960 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3961 if (target.tag == CLASS)
3962 adaptRecursive(source.allparams(), target.allparams());
3963 return null;
3964 }
3966 @Override
3967 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3968 if (target.tag == ARRAY)
3969 adaptRecursive(elemtype(source), elemtype(target));
3970 return null;
3971 }
3973 @Override
3974 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3975 if (source.isExtendsBound())
3976 adaptRecursive(upperBound(source), upperBound(target));
3977 else if (source.isSuperBound())
3978 adaptRecursive(lowerBound(source), lowerBound(target));
3979 return null;
3980 }
3982 @Override
3983 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3984 // Check to see if there is
3985 // already a mapping for $source$, in which case
3986 // the old mapping will be merged with the new
3987 Type val = mapping.get(source.tsym);
3988 if (val != null) {
3989 if (val.isSuperBound() && target.isSuperBound()) {
3990 val = isSubtype(lowerBound(val), lowerBound(target))
3991 ? target : val;
3992 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3993 val = isSubtype(upperBound(val), upperBound(target))
3994 ? val : target;
3995 } else if (!isSameType(val, target)) {
3996 throw new AdaptFailure();
3997 }
3998 } else {
3999 val = target;
4000 from.append(source);
4001 to.append(target);
4002 }
4003 mapping.put(source.tsym, val);
4004 return null;
4005 }
4007 @Override
4008 public Void visitType(Type source, Type target) {
4009 return null;
4010 }
4012 private Set<TypePair> cache = new HashSet<TypePair>();
4014 private void adaptRecursive(Type source, Type target) {
4015 TypePair pair = new TypePair(source, target);
4016 if (cache.add(pair)) {
4017 try {
4018 visit(source, target);
4019 } finally {
4020 cache.remove(pair);
4021 }
4022 }
4023 }
4025 private void adaptRecursive(List<Type> source, List<Type> target) {
4026 if (source.length() == target.length()) {
4027 while (source.nonEmpty()) {
4028 adaptRecursive(source.head, target.head);
4029 source = source.tail;
4030 target = target.tail;
4031 }
4032 }
4033 }
4034 }
4036 public static class AdaptFailure extends RuntimeException {
4037 static final long serialVersionUID = -7490231548272701566L;
4038 }
4040 private void adaptSelf(Type t,
4041 ListBuffer<Type> from,
4042 ListBuffer<Type> to) {
4043 try {
4044 //if (t.tsym.type != t)
4045 adapt(t.tsym.type, t, from, to);
4046 } catch (AdaptFailure ex) {
4047 // Adapt should never fail calculating a mapping from
4048 // t.tsym.type to t as there can be no merge problem.
4049 throw new AssertionError(ex);
4050 }
4051 }
4052 // </editor-fold>
4054 /**
4055 * Rewrite all type variables (universal quantifiers) in the given
4056 * type to wildcards (existential quantifiers). This is used to
4057 * determine if a cast is allowed. For example, if high is true
4058 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4059 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4060 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4061 * List<Integer>} with a warning.
4062 * @param t a type
4063 * @param high if true return an upper bound; otherwise a lower
4064 * bound
4065 * @param rewriteTypeVars only rewrite captured wildcards if false;
4066 * otherwise rewrite all type variables
4067 * @return the type rewritten with wildcards (existential
4068 * quantifiers) only
4069 */
4070 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4071 return new Rewriter(high, rewriteTypeVars).visit(t);
4072 }
4074 class Rewriter extends UnaryVisitor<Type> {
4076 boolean high;
4077 boolean rewriteTypeVars;
4079 Rewriter(boolean high, boolean rewriteTypeVars) {
4080 this.high = high;
4081 this.rewriteTypeVars = rewriteTypeVars;
4082 }
4084 @Override
4085 public Type visitClassType(ClassType t, Void s) {
4086 ListBuffer<Type> rewritten = new ListBuffer<Type>();
4087 boolean changed = false;
4088 for (Type arg : t.allparams()) {
4089 Type bound = visit(arg);
4090 if (arg != bound) {
4091 changed = true;
4092 }
4093 rewritten.append(bound);
4094 }
4095 if (changed)
4096 return subst(t.tsym.type,
4097 t.tsym.type.allparams(),
4098 rewritten.toList());
4099 else
4100 return t;
4101 }
4103 public Type visitType(Type t, Void s) {
4104 return high ? upperBound(t) : lowerBound(t);
4105 }
4107 @Override
4108 public Type visitCapturedType(CapturedType t, Void s) {
4109 Type w_bound = t.wildcard.type;
4110 Type bound = w_bound.contains(t) ?
4111 erasure(w_bound) :
4112 visit(w_bound);
4113 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4114 }
4116 @Override
4117 public Type visitTypeVar(TypeVar t, Void s) {
4118 if (rewriteTypeVars) {
4119 Type bound = t.bound.contains(t) ?
4120 erasure(t.bound) :
4121 visit(t.bound);
4122 return rewriteAsWildcardType(bound, t, EXTENDS);
4123 } else {
4124 return t;
4125 }
4126 }
4128 @Override
4129 public Type visitWildcardType(WildcardType t, Void s) {
4130 Type bound2 = visit(t.type);
4131 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4132 }
4134 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4135 switch (bk) {
4136 case EXTENDS: return high ?
4137 makeExtendsWildcard(B(bound), formal) :
4138 makeExtendsWildcard(syms.objectType, formal);
4139 case SUPER: return high ?
4140 makeSuperWildcard(syms.botType, formal) :
4141 makeSuperWildcard(B(bound), formal);
4142 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4143 default:
4144 Assert.error("Invalid bound kind " + bk);
4145 return null;
4146 }
4147 }
4149 Type B(Type t) {
4150 while (t.tag == WILDCARD) {
4151 WildcardType w = (WildcardType)t;
4152 t = high ?
4153 w.getExtendsBound() :
4154 w.getSuperBound();
4155 if (t == null) {
4156 t = high ? syms.objectType : syms.botType;
4157 }
4158 }
4159 return t;
4160 }
4161 }
4164 /**
4165 * Create a wildcard with the given upper (extends) bound; create
4166 * an unbounded wildcard if bound is Object.
4167 *
4168 * @param bound the upper bound
4169 * @param formal the formal type parameter that will be
4170 * substituted by the wildcard
4171 */
4172 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4173 if (bound == syms.objectType) {
4174 return new WildcardType(syms.objectType,
4175 BoundKind.UNBOUND,
4176 syms.boundClass,
4177 formal);
4178 } else {
4179 return new WildcardType(bound,
4180 BoundKind.EXTENDS,
4181 syms.boundClass,
4182 formal);
4183 }
4184 }
4186 /**
4187 * Create a wildcard with the given lower (super) bound; create an
4188 * unbounded wildcard if bound is bottom (type of {@code null}).
4189 *
4190 * @param bound the lower bound
4191 * @param formal the formal type parameter that will be
4192 * substituted by the wildcard
4193 */
4194 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4195 if (bound.tag == BOT) {
4196 return new WildcardType(syms.objectType,
4197 BoundKind.UNBOUND,
4198 syms.boundClass,
4199 formal);
4200 } else {
4201 return new WildcardType(bound,
4202 BoundKind.SUPER,
4203 syms.boundClass,
4204 formal);
4205 }
4206 }
4208 /**
4209 * A wrapper for a type that allows use in sets.
4210 */
4211 public static class UniqueType {
4212 public final Type type;
4213 final Types types;
4215 public UniqueType(Type type, Types types) {
4216 this.type = type;
4217 this.types = types;
4218 }
4220 public int hashCode() {
4221 return types.hashCode(type);
4222 }
4224 public boolean equals(Object obj) {
4225 return (obj instanceof UniqueType) &&
4226 types.isSameType(type, ((UniqueType)obj).type);
4227 }
4229 public String toString() {
4230 return type.toString();
4231 }
4233 }
4234 // </editor-fold>
4236 // <editor-fold defaultstate="collapsed" desc="Visitors">
4237 /**
4238 * A default visitor for types. All visitor methods except
4239 * visitType are implemented by delegating to visitType. Concrete
4240 * subclasses must provide an implementation of visitType and can
4241 * override other methods as needed.
4242 *
4243 * @param <R> the return type of the operation implemented by this
4244 * visitor; use Void if no return type is needed.
4245 * @param <S> the type of the second argument (the first being the
4246 * type itself) of the operation implemented by this visitor; use
4247 * Void if a second argument is not needed.
4248 */
4249 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4250 final public R visit(Type t, S s) { return t.accept(this, s); }
4251 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4252 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4253 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4254 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4255 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4256 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4257 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4258 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4259 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4260 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4261 // Pretend annotations don't exist
4262 public R visitAnnotatedType(AnnotatedType t, S s) { return visit(t.underlyingType, s); }
4263 }
4265 /**
4266 * A default visitor for symbols. All visitor methods except
4267 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4268 * subclasses must provide an implementation of visitSymbol and can
4269 * override other methods as needed.
4270 *
4271 * @param <R> the return type of the operation implemented by this
4272 * visitor; use Void if no return type is needed.
4273 * @param <S> the type of the second argument (the first being the
4274 * symbol itself) of the operation implemented by this visitor; use
4275 * Void if a second argument is not needed.
4276 */
4277 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4278 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
4279 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4280 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4281 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4282 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4283 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4284 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4285 }
4287 /**
4288 * A <em>simple</em> visitor for types. This visitor is simple as
4289 * captured wildcards, for-all types (generic methods), and
4290 * undetermined type variables (part of inference) are hidden.
4291 * Captured wildcards are hidden by treating them as type
4292 * variables and the rest are hidden by visiting their qtypes.
4293 *
4294 * @param <R> the return type of the operation implemented by this
4295 * visitor; use Void if no return type is needed.
4296 * @param <S> the type of the second argument (the first being the
4297 * type itself) of the operation implemented by this visitor; use
4298 * Void if a second argument is not needed.
4299 */
4300 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4301 @Override
4302 public R visitCapturedType(CapturedType t, S s) {
4303 return visitTypeVar(t, s);
4304 }
4305 @Override
4306 public R visitForAll(ForAll t, S s) {
4307 return visit(t.qtype, s);
4308 }
4309 @Override
4310 public R visitUndetVar(UndetVar t, S s) {
4311 return visit(t.qtype, s);
4312 }
4313 }
4315 /**
4316 * A plain relation on types. That is a 2-ary function on the
4317 * form Type × Type → Boolean.
4318 * <!-- In plain text: Type x Type -> Boolean -->
4319 */
4320 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4322 /**
4323 * A convenience visitor for implementing operations that only
4324 * require one argument (the type itself), that is, unary
4325 * operations.
4326 *
4327 * @param <R> the return type of the operation implemented by this
4328 * visitor; use Void if no return type is needed.
4329 */
4330 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4331 final public R visit(Type t) { return t.accept(this, null); }
4332 }
4334 /**
4335 * A visitor for implementing a mapping from types to types. The
4336 * default behavior of this class is to implement the identity
4337 * mapping (mapping a type to itself). This can be overridden in
4338 * subclasses.
4339 *
4340 * @param <S> the type of the second argument (the first being the
4341 * type itself) of this mapping; use Void if a second argument is
4342 * not needed.
4343 */
4344 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4345 final public Type visit(Type t) { return t.accept(this, null); }
4346 public Type visitType(Type t, S s) { return t; }
4347 }
4348 // </editor-fold>
4351 // <editor-fold defaultstate="collapsed" desc="Annotation support">
4353 public RetentionPolicy getRetention(Attribute.Compound a) {
4354 return getRetention(a.type.tsym);
4355 }
4357 public RetentionPolicy getRetention(Symbol sym) {
4358 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
4359 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
4360 if (c != null) {
4361 Attribute value = c.member(names.value);
4362 if (value != null && value instanceof Attribute.Enum) {
4363 Name levelName = ((Attribute.Enum)value).value.name;
4364 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
4365 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
4366 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
4367 else ;// /* fail soft */ throw new AssertionError(levelName);
4368 }
4369 }
4370 return vis;
4371 }
4372 // </editor-fold>
4374 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
4376 public static abstract class SignatureGenerator {
4378 private final Types types;
4380 protected abstract void append(char ch);
4381 protected abstract void append(byte[] ba);
4382 protected abstract void append(Name name);
4383 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
4385 protected SignatureGenerator(Types types) {
4386 this.types = types;
4387 }
4389 /**
4390 * Assemble signature of given type in string buffer.
4391 */
4392 public void assembleSig(Type type) {
4393 type = type.unannotatedType();
4394 switch (type.getTag()) {
4395 case BYTE:
4396 append('B');
4397 break;
4398 case SHORT:
4399 append('S');
4400 break;
4401 case CHAR:
4402 append('C');
4403 break;
4404 case INT:
4405 append('I');
4406 break;
4407 case LONG:
4408 append('J');
4409 break;
4410 case FLOAT:
4411 append('F');
4412 break;
4413 case DOUBLE:
4414 append('D');
4415 break;
4416 case BOOLEAN:
4417 append('Z');
4418 break;
4419 case VOID:
4420 append('V');
4421 break;
4422 case CLASS:
4423 append('L');
4424 assembleClassSig(type);
4425 append(';');
4426 break;
4427 case ARRAY:
4428 ArrayType at = (ArrayType) type;
4429 append('[');
4430 assembleSig(at.elemtype);
4431 break;
4432 case METHOD:
4433 MethodType mt = (MethodType) type;
4434 append('(');
4435 assembleSig(mt.argtypes);
4436 append(')');
4437 assembleSig(mt.restype);
4438 if (hasTypeVar(mt.thrown)) {
4439 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
4440 append('^');
4441 assembleSig(l.head);
4442 }
4443 }
4444 break;
4445 case WILDCARD: {
4446 Type.WildcardType ta = (Type.WildcardType) type;
4447 switch (ta.kind) {
4448 case SUPER:
4449 append('-');
4450 assembleSig(ta.type);
4451 break;
4452 case EXTENDS:
4453 append('+');
4454 assembleSig(ta.type);
4455 break;
4456 case UNBOUND:
4457 append('*');
4458 break;
4459 default:
4460 throw new AssertionError(ta.kind);
4461 }
4462 break;
4463 }
4464 case TYPEVAR:
4465 append('T');
4466 append(type.tsym.name);
4467 append(';');
4468 break;
4469 case FORALL:
4470 Type.ForAll ft = (Type.ForAll) type;
4471 assembleParamsSig(ft.tvars);
4472 assembleSig(ft.qtype);
4473 break;
4474 default:
4475 throw new AssertionError("typeSig " + type.getTag());
4476 }
4477 }
4479 public boolean hasTypeVar(List<Type> l) {
4480 while (l.nonEmpty()) {
4481 if (l.head.hasTag(TypeTag.TYPEVAR)) {
4482 return true;
4483 }
4484 l = l.tail;
4485 }
4486 return false;
4487 }
4489 public void assembleClassSig(Type type) {
4490 type = type.unannotatedType();
4491 ClassType ct = (ClassType) type;
4492 ClassSymbol c = (ClassSymbol) ct.tsym;
4493 classReference(c);
4494 Type outer = ct.getEnclosingType();
4495 if (outer.allparams().nonEmpty()) {
4496 boolean rawOuter =
4497 c.owner.kind == Kinds.MTH || // either a local class
4498 c.name == types.names.empty; // or anonymous
4499 assembleClassSig(rawOuter
4500 ? types.erasure(outer)
4501 : outer);
4502 append('.');
4503 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
4504 append(rawOuter
4505 ? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength())
4506 : c.name);
4507 } else {
4508 append(externalize(c.flatname));
4509 }
4510 if (ct.getTypeArguments().nonEmpty()) {
4511 append('<');
4512 assembleSig(ct.getTypeArguments());
4513 append('>');
4514 }
4515 }
4517 public void assembleParamsSig(List<Type> typarams) {
4518 append('<');
4519 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
4520 Type.TypeVar tvar = (Type.TypeVar) ts.head;
4521 append(tvar.tsym.name);
4522 List<Type> bounds = types.getBounds(tvar);
4523 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
4524 append(':');
4525 }
4526 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
4527 append(':');
4528 assembleSig(l.head);
4529 }
4530 }
4531 append('>');
4532 }
4534 private void assembleSig(List<Type> types) {
4535 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
4536 assembleSig(ts.head);
4537 }
4538 }
4539 }
4540 // </editor-fold>
4541 }
