Mercurial > jdk8-mips64-public > langtools / file revision
src/share/classes/com/sun/tools/javac/code/Types.java@f1f605f85850
src/share/classes/com/sun/tools/javac/code/Types.java
Fri, 15 Feb 2013 18:40:38 -0800
- author
- rfield
- date
- Fri, 15 Feb 2013 18:40:38 -0800
- changeset 1587
- f1f605f85850
- parent 1582
- 3cd997b9fd84
- child 1598
- 7ac9242d2ca6
- permissions
- -rw-r--r--
8004969: Generate $deserializeLambda$ method
8006763: super in method reference used in anonymous class - ClassFormatError is produced
8005632: Inner classes within lambdas cause build failures
8005653: Lambdas containing inner classes referencing external type variables do not correctly parameterize the inner classes
Reviewed-by: mcimadamore
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 new MethodType(mt.getParameterTypes(), mt.getReturnType(), thrown1, syms.methodClass);
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 if (capture(site) != site) {
576 Type formalInterface = site.tsym.type;
577 ListBuffer<Type> typeargs = ListBuffer.lb();
578 List<Type> actualTypeargs = site.getTypeArguments();
579 //simply replace the wildcards with its bound
580 for (Type t : formalInterface.getTypeArguments()) {
581 if (actualTypeargs.head.hasTag(WILDCARD)) {
582 WildcardType wt = (WildcardType)actualTypeargs.head;
583 typeargs.append(wt.type);
584 } else {
585 typeargs.append(actualTypeargs.head);
586 }
587 actualTypeargs = actualTypeargs.tail;
588 }
589 return subst(formalInterface, formalInterface.getTypeArguments(), typeargs.toList());
590 } else {
591 return site;
592 }
593 }
594 // </editor-fold>
596 /**
597 * Scope filter used to skip methods that should be ignored (such as methods
598 * overridden by j.l.Object) during function interface conversion/marker interface checks
599 */
600 class DescriptorFilter implements Filter<Symbol> {
602 TypeSymbol origin;
604 DescriptorFilter(TypeSymbol origin) {
605 this.origin = origin;
606 }
608 @Override
609 public boolean accepts(Symbol sym) {
610 return sym.kind == Kinds.MTH &&
611 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
612 !overridesObjectMethod(origin, sym) &&
613 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
614 }
615 };
617 // <editor-fold defaultstate="collapsed" desc="isMarker">
619 /**
620 * A cache that keeps track of marker interfaces
621 */
622 class MarkerCache {
624 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<TypeSymbol, Entry>();
626 class Entry {
627 final boolean isMarkerIntf;
628 final int prevMark;
630 public Entry(boolean isMarkerIntf,
631 int prevMark) {
632 this.isMarkerIntf = isMarkerIntf;
633 this.prevMark = prevMark;
634 }
636 boolean matches(int mark) {
637 return this.prevMark == mark;
638 }
639 }
641 boolean get(TypeSymbol origin) throws FunctionDescriptorLookupError {
642 Entry e = _map.get(origin);
643 CompoundScope members = membersClosure(origin.type, false);
644 if (e == null ||
645 !e.matches(members.getMark())) {
646 boolean isMarkerIntf = isMarkerInterfaceInternal(origin, members);
647 _map.put(origin, new Entry(isMarkerIntf, members.getMark()));
648 return isMarkerIntf;
649 }
650 else {
651 return e.isMarkerIntf;
652 }
653 }
655 /**
656 * Is given symbol a marker interface
657 */
658 public boolean isMarkerInterfaceInternal(TypeSymbol origin, CompoundScope membersCache) throws FunctionDescriptorLookupError {
659 return !origin.isInterface() ?
660 false :
661 !membersCache.getElements(new DescriptorFilter(origin)).iterator().hasNext();
662 }
663 }
665 private MarkerCache markerCache = new MarkerCache();
667 /**
668 * Is given type a marker interface?
669 */
670 public boolean isMarkerInterface(Type site) {
671 return markerCache.get(site.tsym);
672 }
673 // </editor-fold>
675 // <editor-fold defaultstate="collapsed" desc="isSubtype">
676 /**
677 * Is t an unchecked subtype of s?
678 */
679 public boolean isSubtypeUnchecked(Type t, Type s) {
680 return isSubtypeUnchecked(t, s, noWarnings);
681 }
682 /**
683 * Is t an unchecked subtype of s?
684 */
685 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
686 boolean result = isSubtypeUncheckedInternal(t, s, warn);
687 if (result) {
688 checkUnsafeVarargsConversion(t, s, warn);
689 }
690 return result;
691 }
692 //where
693 private boolean isSubtypeUncheckedInternal(Type t, Type s, Warner warn) {
694 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
695 t = t.unannotatedType();
696 s = s.unannotatedType();
697 if (((ArrayType)t).elemtype.isPrimitive()) {
698 return isSameType(elemtype(t), elemtype(s));
699 } else {
700 return isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
701 }
702 } else if (isSubtype(t, s)) {
703 return true;
704 }
705 else if (t.tag == TYPEVAR) {
706 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
707 }
708 else if (!s.isRaw()) {
709 Type t2 = asSuper(t, s.tsym);
710 if (t2 != null && t2.isRaw()) {
711 if (isReifiable(s))
712 warn.silentWarn(LintCategory.UNCHECKED);
713 else
714 warn.warn(LintCategory.UNCHECKED);
715 return true;
716 }
717 }
718 return false;
719 }
721 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
722 if (t.tag != ARRAY || isReifiable(t))
723 return;
724 t = t.unannotatedType();
725 s = s.unannotatedType();
726 ArrayType from = (ArrayType)t;
727 boolean shouldWarn = false;
728 switch (s.tag) {
729 case ARRAY:
730 ArrayType to = (ArrayType)s;
731 shouldWarn = from.isVarargs() &&
732 !to.isVarargs() &&
733 !isReifiable(from);
734 break;
735 case CLASS:
736 shouldWarn = from.isVarargs();
737 break;
738 }
739 if (shouldWarn) {
740 warn.warn(LintCategory.VARARGS);
741 }
742 }
744 /**
745 * Is t a subtype of s?<br>
746 * (not defined for Method and ForAll types)
747 */
748 final public boolean isSubtype(Type t, Type s) {
749 return isSubtype(t, s, true);
750 }
751 final public boolean isSubtypeNoCapture(Type t, Type s) {
752 return isSubtype(t, s, false);
753 }
754 public boolean isSubtype(Type t, Type s, boolean capture) {
755 if (t == s)
756 return true;
758 t = t.unannotatedType();
759 s = s.unannotatedType();
761 if (t == s)
762 return true;
764 if (s.isPartial())
765 return isSuperType(s, t);
767 if (s.isCompound()) {
768 for (Type s2 : interfaces(s).prepend(supertype(s))) {
769 if (!isSubtype(t, s2, capture))
770 return false;
771 }
772 return true;
773 }
775 Type lower = lowerBound(s);
776 if (s != lower)
777 return isSubtype(capture ? capture(t) : t, lower, false);
779 return isSubtype.visit(capture ? capture(t) : t, s);
780 }
781 // where
782 private TypeRelation isSubtype = new TypeRelation()
783 {
784 public Boolean visitType(Type t, Type s) {
785 switch (t.tag) {
786 case BYTE:
787 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
788 case CHAR:
789 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
790 case SHORT: case INT: case LONG:
791 case FLOAT: case DOUBLE:
792 return t.getTag().isSubRangeOf(s.getTag());
793 case BOOLEAN: case VOID:
794 return t.hasTag(s.getTag());
795 case TYPEVAR:
796 return isSubtypeNoCapture(t.getUpperBound(), s);
797 case BOT:
798 return
799 s.hasTag(BOT) || s.hasTag(CLASS) ||
800 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
801 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
802 case NONE:
803 return false;
804 default:
805 throw new AssertionError("isSubtype " + t.tag);
806 }
807 }
809 private Set<TypePair> cache = new HashSet<TypePair>();
811 private boolean containsTypeRecursive(Type t, Type s) {
812 TypePair pair = new TypePair(t, s);
813 if (cache.add(pair)) {
814 try {
815 return containsType(t.getTypeArguments(),
816 s.getTypeArguments());
817 } finally {
818 cache.remove(pair);
819 }
820 } else {
821 return containsType(t.getTypeArguments(),
822 rewriteSupers(s).getTypeArguments());
823 }
824 }
826 private Type rewriteSupers(Type t) {
827 if (!t.isParameterized())
828 return t;
829 ListBuffer<Type> from = lb();
830 ListBuffer<Type> to = lb();
831 adaptSelf(t, from, to);
832 if (from.isEmpty())
833 return t;
834 ListBuffer<Type> rewrite = lb();
835 boolean changed = false;
836 for (Type orig : to.toList()) {
837 Type s = rewriteSupers(orig);
838 if (s.isSuperBound() && !s.isExtendsBound()) {
839 s = new WildcardType(syms.objectType,
840 BoundKind.UNBOUND,
841 syms.boundClass);
842 changed = true;
843 } else if (s != orig) {
844 s = new WildcardType(upperBound(s),
845 BoundKind.EXTENDS,
846 syms.boundClass);
847 changed = true;
848 }
849 rewrite.append(s);
850 }
851 if (changed)
852 return subst(t.tsym.type, from.toList(), rewrite.toList());
853 else
854 return t;
855 }
857 @Override
858 public Boolean visitClassType(ClassType t, Type s) {
859 Type sup = asSuper(t, s.tsym);
860 return sup != null
861 && sup.tsym == s.tsym
862 // You're not allowed to write
863 // Vector<Object> vec = new Vector<String>();
864 // But with wildcards you can write
865 // Vector<? extends Object> vec = new Vector<String>();
866 // which means that subtype checking must be done
867 // here instead of same-type checking (via containsType).
868 && (!s.isParameterized() || containsTypeRecursive(s, sup))
869 && isSubtypeNoCapture(sup.getEnclosingType(),
870 s.getEnclosingType());
871 }
873 @Override
874 public Boolean visitArrayType(ArrayType t, Type s) {
875 if (s.tag == ARRAY) {
876 if (t.elemtype.isPrimitive())
877 return isSameType(t.elemtype, elemtype(s));
878 else
879 return isSubtypeNoCapture(t.elemtype, elemtype(s));
880 }
882 if (s.tag == CLASS) {
883 Name sname = s.tsym.getQualifiedName();
884 return sname == names.java_lang_Object
885 || sname == names.java_lang_Cloneable
886 || sname == names.java_io_Serializable;
887 }
889 return false;
890 }
892 @Override
893 public Boolean visitUndetVar(UndetVar t, Type s) {
894 //todo: test against origin needed? or replace with substitution?
895 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN) {
896 return true;
897 } else if (s.tag == BOT) {
898 //if 's' is 'null' there's no instantiated type U for which
899 //U <: s (but 'null' itself, which is not a valid type)
900 return false;
901 }
903 t.addBound(InferenceBound.UPPER, s, Types.this);
904 return true;
905 }
907 @Override
908 public Boolean visitErrorType(ErrorType t, Type s) {
909 return true;
910 }
911 };
913 /**
914 * Is t a subtype of every type in given list `ts'?<br>
915 * (not defined for Method and ForAll types)<br>
916 * Allows unchecked conversions.
917 */
918 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
919 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
920 if (!isSubtypeUnchecked(t, l.head, warn))
921 return false;
922 return true;
923 }
925 /**
926 * Are corresponding elements of ts subtypes of ss? If lists are
927 * of different length, return false.
928 */
929 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
930 while (ts.tail != null && ss.tail != null
931 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
932 isSubtype(ts.head, ss.head)) {
933 ts = ts.tail;
934 ss = ss.tail;
935 }
936 return ts.tail == null && ss.tail == null;
937 /*inlined: ts.isEmpty() && ss.isEmpty();*/
938 }
940 /**
941 * Are corresponding elements of ts subtypes of ss, allowing
942 * unchecked conversions? If lists are of different length,
943 * return false.
944 **/
945 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
946 while (ts.tail != null && ss.tail != null
947 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
948 isSubtypeUnchecked(ts.head, ss.head, warn)) {
949 ts = ts.tail;
950 ss = ss.tail;
951 }
952 return ts.tail == null && ss.tail == null;
953 /*inlined: ts.isEmpty() && ss.isEmpty();*/
954 }
955 // </editor-fold>
957 // <editor-fold defaultstate="collapsed" desc="isSuperType">
958 /**
959 * Is t a supertype of s?
960 */
961 public boolean isSuperType(Type t, Type s) {
962 switch (t.tag) {
963 case ERROR:
964 return true;
965 case UNDETVAR: {
966 UndetVar undet = (UndetVar)t;
967 if (t == s ||
968 undet.qtype == s ||
969 s.tag == ERROR ||
970 s.tag == BOT) return true;
971 undet.addBound(InferenceBound.LOWER, s, this);
972 return true;
973 }
974 default:
975 return isSubtype(s, t);
976 }
977 }
978 // </editor-fold>
980 // <editor-fold defaultstate="collapsed" desc="isSameType">
981 /**
982 * Are corresponding elements of the lists the same type? If
983 * lists are of different length, return false.
984 */
985 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
986 return isSameTypes(ts, ss, false);
987 }
988 public boolean isSameTypes(List<Type> ts, List<Type> ss, boolean strict) {
989 while (ts.tail != null && ss.tail != null
990 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
991 isSameType(ts.head, ss.head, strict)) {
992 ts = ts.tail;
993 ss = ss.tail;
994 }
995 return ts.tail == null && ss.tail == null;
996 /*inlined: ts.isEmpty() && ss.isEmpty();*/
997 }
999 /**
1000 * Is t the same type as s?
1001 */
1002 public boolean isSameType(Type t, Type s) {
1003 return isSameType(t, s, false);
1004 }
1005 public boolean isSameType(Type t, Type s, boolean strict) {
1006 return strict ?
1007 isSameTypeStrict.visit(t, s) :
1008 isSameTypeLoose.visit(t, s);
1009 }
1010 // where
1011 abstract class SameTypeVisitor extends TypeRelation {
1013 public Boolean visitType(Type t, Type s) {
1014 if (t == s)
1015 return true;
1017 if (s.isPartial())
1018 return visit(s, t);
1020 switch (t.tag) {
1021 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1022 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
1023 return t.tag == s.tag;
1024 case TYPEVAR: {
1025 if (s.tag == TYPEVAR) {
1026 //type-substitution does not preserve type-var types
1027 //check that type var symbols and bounds are indeed the same
1028 return sameTypeVars((TypeVar)t, (TypeVar)s);
1029 }
1030 else {
1031 //special case for s == ? super X, where upper(s) = u
1032 //check that u == t, where u has been set by Type.withTypeVar
1033 return s.isSuperBound() &&
1034 !s.isExtendsBound() &&
1035 visit(t, upperBound(s));
1036 }
1037 }
1038 default:
1039 throw new AssertionError("isSameType " + t.tag);
1040 }
1041 }
1043 abstract boolean sameTypeVars(TypeVar tv1, TypeVar tv2);
1045 @Override
1046 public Boolean visitWildcardType(WildcardType t, Type s) {
1047 if (s.isPartial())
1048 return visit(s, t);
1049 else
1050 return false;
1051 }
1053 @Override
1054 public Boolean visitClassType(ClassType t, Type s) {
1055 if (t == s)
1056 return true;
1058 if (s.isPartial())
1059 return visit(s, t);
1061 if (s.isSuperBound() && !s.isExtendsBound())
1062 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
1064 if (t.isCompound() && s.isCompound()) {
1065 if (!visit(supertype(t), supertype(s)))
1066 return false;
1068 HashSet<UniqueType> set = new HashSet<UniqueType>();
1069 for (Type x : interfaces(t))
1070 set.add(new UniqueType(x, Types.this));
1071 for (Type x : interfaces(s)) {
1072 if (!set.remove(new UniqueType(x, Types.this)))
1073 return false;
1074 }
1075 return (set.isEmpty());
1076 }
1077 return t.tsym == s.tsym
1078 && visit(t.getEnclosingType(), s.getEnclosingType())
1079 && containsTypes(t.getTypeArguments(), s.getTypeArguments());
1080 }
1082 abstract protected boolean containsTypes(List<Type> ts1, List<Type> ts2);
1084 @Override
1085 public Boolean visitArrayType(ArrayType t, Type s) {
1086 if (t == s)
1087 return true;
1089 if (s.isPartial())
1090 return visit(s, t);
1092 return s.hasTag(ARRAY)
1093 && containsTypeEquivalent(t.elemtype, elemtype(s));
1094 }
1096 @Override
1097 public Boolean visitMethodType(MethodType t, Type s) {
1098 // isSameType for methods does not take thrown
1099 // exceptions into account!
1100 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
1101 }
1103 @Override
1104 public Boolean visitPackageType(PackageType t, Type s) {
1105 return t == s;
1106 }
1108 @Override
1109 public Boolean visitForAll(ForAll t, Type s) {
1110 if (s.tag != FORALL)
1111 return false;
1113 ForAll forAll = (ForAll)s;
1114 return hasSameBounds(t, forAll)
1115 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1116 }
1118 @Override
1119 public Boolean visitUndetVar(UndetVar t, Type s) {
1120 if (s.tag == WILDCARD)
1121 // FIXME, this might be leftovers from before capture conversion
1122 return false;
1124 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
1125 return true;
1127 t.addBound(InferenceBound.EQ, s, Types.this);
1129 return true;
1130 }
1132 @Override
1133 public Boolean visitErrorType(ErrorType t, Type s) {
1134 return true;
1135 }
1136 }
1138 /**
1139 * Standard type-equality relation - type variables are considered
1140 * equals if they share the same type symbol.
1141 */
1142 TypeRelation isSameTypeLoose = new SameTypeVisitor() {
1143 @Override
1144 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
1145 return tv1.tsym == tv2.tsym && visit(tv1.getUpperBound(), tv2.getUpperBound());
1146 }
1147 @Override
1148 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
1149 return containsTypeEquivalent(ts1, ts2);
1150 }
1151 };
1153 /**
1154 * Strict type-equality relation - type variables are considered
1155 * equals if they share the same object identity.
1156 */
1157 TypeRelation isSameTypeStrict = new SameTypeVisitor() {
1158 @Override
1159 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
1160 return tv1 == tv2;
1161 }
1162 @Override
1163 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
1164 return isSameTypes(ts1, ts2, true);
1165 }
1166 };
1167 // </editor-fold>
1169 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1170 public boolean containedBy(Type t, Type s) {
1171 switch (t.tag) {
1172 case UNDETVAR:
1173 if (s.tag == WILDCARD) {
1174 UndetVar undetvar = (UndetVar)t;
1175 WildcardType wt = (WildcardType)s;
1176 switch(wt.kind) {
1177 case UNBOUND: //similar to ? extends Object
1178 case EXTENDS: {
1179 Type bound = upperBound(s);
1180 undetvar.addBound(InferenceBound.UPPER, bound, this);
1181 break;
1182 }
1183 case SUPER: {
1184 Type bound = lowerBound(s);
1185 undetvar.addBound(InferenceBound.LOWER, bound, this);
1186 break;
1187 }
1188 }
1189 return true;
1190 } else {
1191 return isSameType(t, s);
1192 }
1193 case ERROR:
1194 return true;
1195 default:
1196 return containsType(s, t);
1197 }
1198 }
1200 boolean containsType(List<Type> ts, List<Type> ss) {
1201 while (ts.nonEmpty() && ss.nonEmpty()
1202 && containsType(ts.head, ss.head)) {
1203 ts = ts.tail;
1204 ss = ss.tail;
1205 }
1206 return ts.isEmpty() && ss.isEmpty();
1207 }
1209 /**
1210 * Check if t contains s.
1211 *
1212 * <p>T contains S if:
1213 *
1214 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1215 *
1216 * <p>This relation is only used by ClassType.isSubtype(), that
1217 * is,
1218 *
1219 * <p>{@code C<S> <: C<T> if T contains S.}
1220 *
1221 * <p>Because of F-bounds, this relation can lead to infinite
1222 * recursion. Thus we must somehow break that recursion. Notice
1223 * that containsType() is only called from ClassType.isSubtype().
1224 * Since the arguments have already been checked against their
1225 * bounds, we know:
1226 *
1227 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1228 *
1229 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1230 *
1231 * @param t a type
1232 * @param s a type
1233 */
1234 public boolean containsType(Type t, Type s) {
1235 return containsType.visit(t, s);
1236 }
1237 // where
1238 private TypeRelation containsType = new TypeRelation() {
1240 private Type U(Type t) {
1241 while (t.tag == WILDCARD) {
1242 WildcardType w = (WildcardType)t;
1243 if (w.isSuperBound())
1244 return w.bound == null ? syms.objectType : w.bound.bound;
1245 else
1246 t = w.type;
1247 }
1248 return t;
1249 }
1251 private Type L(Type t) {
1252 while (t.tag == WILDCARD) {
1253 WildcardType w = (WildcardType)t;
1254 if (w.isExtendsBound())
1255 return syms.botType;
1256 else
1257 t = w.type;
1258 }
1259 return t;
1260 }
1262 public Boolean visitType(Type t, Type s) {
1263 if (s.isPartial())
1264 return containedBy(s, t);
1265 else
1266 return isSameType(t, s);
1267 }
1269 // void debugContainsType(WildcardType t, Type s) {
1270 // System.err.println();
1271 // System.err.format(" does %s contain %s?%n", t, s);
1272 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1273 // upperBound(s), s, t, U(t),
1274 // t.isSuperBound()
1275 // || isSubtypeNoCapture(upperBound(s), U(t)));
1276 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1277 // L(t), t, s, lowerBound(s),
1278 // t.isExtendsBound()
1279 // || isSubtypeNoCapture(L(t), lowerBound(s)));
1280 // System.err.println();
1281 // }
1283 @Override
1284 public Boolean visitWildcardType(WildcardType t, Type s) {
1285 if (s.isPartial())
1286 return containedBy(s, t);
1287 else {
1288 // debugContainsType(t, s);
1289 return isSameWildcard(t, s)
1290 || isCaptureOf(s, t)
1291 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
1292 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
1293 }
1294 }
1296 @Override
1297 public Boolean visitUndetVar(UndetVar t, Type s) {
1298 if (s.tag != WILDCARD)
1299 return isSameType(t, s);
1300 else
1301 return false;
1302 }
1304 @Override
1305 public Boolean visitErrorType(ErrorType t, Type s) {
1306 return true;
1307 }
1308 };
1310 public boolean isCaptureOf(Type s, WildcardType t) {
1311 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
1312 return false;
1313 return isSameWildcard(t, ((CapturedType)s).wildcard);
1314 }
1316 public boolean isSameWildcard(WildcardType t, Type s) {
1317 if (s.tag != WILDCARD)
1318 return false;
1319 WildcardType w = (WildcardType)s;
1320 return w.kind == t.kind && w.type == t.type;
1321 }
1323 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1324 while (ts.nonEmpty() && ss.nonEmpty()
1325 && containsTypeEquivalent(ts.head, ss.head)) {
1326 ts = ts.tail;
1327 ss = ss.tail;
1328 }
1329 return ts.isEmpty() && ss.isEmpty();
1330 }
1331 // </editor-fold>
1333 // <editor-fold defaultstate="collapsed" desc="isCastable">
1334 public boolean isCastable(Type t, Type s) {
1335 return isCastable(t, s, noWarnings);
1336 }
1338 /**
1339 * Is t is castable to s?<br>
1340 * s is assumed to be an erased type.<br>
1341 * (not defined for Method and ForAll types).
1342 */
1343 public boolean isCastable(Type t, Type s, Warner warn) {
1344 if (t == s)
1345 return true;
1347 if (t.isPrimitive() != s.isPrimitive())
1348 return allowBoxing && (
1349 isConvertible(t, s, warn)
1350 || (allowObjectToPrimitiveCast &&
1351 s.isPrimitive() &&
1352 isSubtype(boxedClass(s).type, t)));
1353 if (warn != warnStack.head) {
1354 try {
1355 warnStack = warnStack.prepend(warn);
1356 checkUnsafeVarargsConversion(t, s, warn);
1357 return isCastable.visit(t,s);
1358 } finally {
1359 warnStack = warnStack.tail;
1360 }
1361 } else {
1362 return isCastable.visit(t,s);
1363 }
1364 }
1365 // where
1366 private TypeRelation isCastable = new TypeRelation() {
1368 public Boolean visitType(Type t, Type s) {
1369 if (s.tag == ERROR)
1370 return true;
1372 switch (t.tag) {
1373 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1374 case DOUBLE:
1375 return s.isNumeric();
1376 case BOOLEAN:
1377 return s.tag == BOOLEAN;
1378 case VOID:
1379 return false;
1380 case BOT:
1381 return isSubtype(t, s);
1382 default:
1383 throw new AssertionError();
1384 }
1385 }
1387 @Override
1388 public Boolean visitWildcardType(WildcardType t, Type s) {
1389 return isCastable(upperBound(t), s, warnStack.head);
1390 }
1392 @Override
1393 public Boolean visitClassType(ClassType t, Type s) {
1394 if (s.tag == ERROR || s.tag == BOT)
1395 return true;
1397 if (s.tag == TYPEVAR) {
1398 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1399 warnStack.head.warn(LintCategory.UNCHECKED);
1400 return true;
1401 } else {
1402 return false;
1403 }
1404 }
1406 if (t.isCompound()) {
1407 Warner oldWarner = warnStack.head;
1408 warnStack.head = noWarnings;
1409 if (!visit(supertype(t), s))
1410 return false;
1411 for (Type intf : interfaces(t)) {
1412 if (!visit(intf, s))
1413 return false;
1414 }
1415 if (warnStack.head.hasLint(LintCategory.UNCHECKED))
1416 oldWarner.warn(LintCategory.UNCHECKED);
1417 return true;
1418 }
1420 if (s.isCompound()) {
1421 // call recursively to reuse the above code
1422 return visitClassType((ClassType)s, t);
1423 }
1425 if (s.tag == CLASS || s.tag == ARRAY) {
1426 boolean upcast;
1427 if ((upcast = isSubtype(erasure(t), erasure(s)))
1428 || isSubtype(erasure(s), erasure(t))) {
1429 if (!upcast && s.tag == ARRAY) {
1430 if (!isReifiable(s))
1431 warnStack.head.warn(LintCategory.UNCHECKED);
1432 return true;
1433 } else if (s.isRaw()) {
1434 return true;
1435 } else if (t.isRaw()) {
1436 if (!isUnbounded(s))
1437 warnStack.head.warn(LintCategory.UNCHECKED);
1438 return true;
1439 }
1440 // Assume |a| <: |b|
1441 final Type a = upcast ? t : s;
1442 final Type b = upcast ? s : t;
1443 final boolean HIGH = true;
1444 final boolean LOW = false;
1445 final boolean DONT_REWRITE_TYPEVARS = false;
1446 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1447 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1448 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1449 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1450 Type lowSub = asSub(bLow, aLow.tsym);
1451 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1452 if (highSub == null) {
1453 final boolean REWRITE_TYPEVARS = true;
1454 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1455 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1456 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1457 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1458 lowSub = asSub(bLow, aLow.tsym);
1459 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1460 }
1461 if (highSub != null) {
1462 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1463 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1464 }
1465 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1466 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1467 && !disjointTypes(aLow.allparams(), highSub.allparams())
1468 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1469 if (upcast ? giveWarning(a, b) :
1470 giveWarning(b, a))
1471 warnStack.head.warn(LintCategory.UNCHECKED);
1472 return true;
1473 }
1474 }
1475 if (isReifiable(s))
1476 return isSubtypeUnchecked(a, b);
1477 else
1478 return isSubtypeUnchecked(a, b, warnStack.head);
1479 }
1481 // Sidecast
1482 if (s.tag == CLASS) {
1483 if ((s.tsym.flags() & INTERFACE) != 0) {
1484 return ((t.tsym.flags() & FINAL) == 0)
1485 ? sideCast(t, s, warnStack.head)
1486 : sideCastFinal(t, s, warnStack.head);
1487 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1488 return ((s.tsym.flags() & FINAL) == 0)
1489 ? sideCast(t, s, warnStack.head)
1490 : sideCastFinal(t, s, warnStack.head);
1491 } else {
1492 // unrelated class types
1493 return false;
1494 }
1495 }
1496 }
1497 return false;
1498 }
1500 @Override
1501 public Boolean visitArrayType(ArrayType t, Type s) {
1502 switch (s.tag) {
1503 case ERROR:
1504 case BOT:
1505 return true;
1506 case TYPEVAR:
1507 if (isCastable(s, t, noWarnings)) {
1508 warnStack.head.warn(LintCategory.UNCHECKED);
1509 return true;
1510 } else {
1511 return false;
1512 }
1513 case CLASS:
1514 return isSubtype(t, s);
1515 case ARRAY:
1516 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1517 return elemtype(t).tag == elemtype(s).tag;
1518 } else {
1519 return visit(elemtype(t), elemtype(s));
1520 }
1521 default:
1522 return false;
1523 }
1524 }
1526 @Override
1527 public Boolean visitTypeVar(TypeVar t, Type s) {
1528 switch (s.tag) {
1529 case ERROR:
1530 case BOT:
1531 return true;
1532 case TYPEVAR:
1533 if (isSubtype(t, s)) {
1534 return true;
1535 } else if (isCastable(t.bound, s, noWarnings)) {
1536 warnStack.head.warn(LintCategory.UNCHECKED);
1537 return true;
1538 } else {
1539 return false;
1540 }
1541 default:
1542 return isCastable(t.bound, s, warnStack.head);
1543 }
1544 }
1546 @Override
1547 public Boolean visitErrorType(ErrorType t, Type s) {
1548 return true;
1549 }
1550 };
1551 // </editor-fold>
1553 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1554 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1555 while (ts.tail != null && ss.tail != null) {
1556 if (disjointType(ts.head, ss.head)) return true;
1557 ts = ts.tail;
1558 ss = ss.tail;
1559 }
1560 return false;
1561 }
1563 /**
1564 * Two types or wildcards are considered disjoint if it can be
1565 * proven that no type can be contained in both. It is
1566 * conservative in that it is allowed to say that two types are
1567 * not disjoint, even though they actually are.
1568 *
1569 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1570 * {@code X} and {@code Y} are not disjoint.
1571 */
1572 public boolean disjointType(Type t, Type s) {
1573 return disjointType.visit(t, s);
1574 }
1575 // where
1576 private TypeRelation disjointType = new TypeRelation() {
1578 private Set<TypePair> cache = new HashSet<TypePair>();
1580 public Boolean visitType(Type t, Type s) {
1581 if (s.tag == WILDCARD)
1582 return visit(s, t);
1583 else
1584 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1585 }
1587 private boolean isCastableRecursive(Type t, Type s) {
1588 TypePair pair = new TypePair(t, s);
1589 if (cache.add(pair)) {
1590 try {
1591 return Types.this.isCastable(t, s);
1592 } finally {
1593 cache.remove(pair);
1594 }
1595 } else {
1596 return true;
1597 }
1598 }
1600 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1601 TypePair pair = new TypePair(t, s);
1602 if (cache.add(pair)) {
1603 try {
1604 return Types.this.notSoftSubtype(t, s);
1605 } finally {
1606 cache.remove(pair);
1607 }
1608 } else {
1609 return false;
1610 }
1611 }
1613 @Override
1614 public Boolean visitWildcardType(WildcardType t, Type s) {
1615 if (t.isUnbound())
1616 return false;
1618 if (s.tag != WILDCARD) {
1619 if (t.isExtendsBound())
1620 return notSoftSubtypeRecursive(s, t.type);
1621 else // isSuperBound()
1622 return notSoftSubtypeRecursive(t.type, s);
1623 }
1625 if (s.isUnbound())
1626 return false;
1628 if (t.isExtendsBound()) {
1629 if (s.isExtendsBound())
1630 return !isCastableRecursive(t.type, upperBound(s));
1631 else if (s.isSuperBound())
1632 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1633 } else if (t.isSuperBound()) {
1634 if (s.isExtendsBound())
1635 return notSoftSubtypeRecursive(t.type, upperBound(s));
1636 }
1637 return false;
1638 }
1639 };
1640 // </editor-fold>
1642 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1643 /**
1644 * Returns the lower bounds of the formals of a method.
1645 */
1646 public List<Type> lowerBoundArgtypes(Type t) {
1647 return lowerBounds(t.getParameterTypes());
1648 }
1649 public List<Type> lowerBounds(List<Type> ts) {
1650 return map(ts, lowerBoundMapping);
1651 }
1652 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1653 public Type apply(Type t) {
1654 return lowerBound(t);
1655 }
1656 };
1657 // </editor-fold>
1659 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1660 /**
1661 * This relation answers the question: is impossible that
1662 * something of type `t' can be a subtype of `s'? This is
1663 * different from the question "is `t' not a subtype of `s'?"
1664 * when type variables are involved: Integer is not a subtype of T
1665 * where {@code <T extends Number>} but it is not true that Integer cannot
1666 * possibly be a subtype of T.
1667 */
1668 public boolean notSoftSubtype(Type t, Type s) {
1669 if (t == s) return false;
1670 if (t.tag == TYPEVAR) {
1671 TypeVar tv = (TypeVar) t;
1672 return !isCastable(tv.bound,
1673 relaxBound(s),
1674 noWarnings);
1675 }
1676 if (s.tag != WILDCARD)
1677 s = upperBound(s);
1679 return !isSubtype(t, relaxBound(s));
1680 }
1682 private Type relaxBound(Type t) {
1683 if (t.tag == TYPEVAR) {
1684 while (t.tag == TYPEVAR)
1685 t = t.getUpperBound();
1686 t = rewriteQuantifiers(t, true, true);
1687 }
1688 return t;
1689 }
1690 // </editor-fold>
1692 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1693 public boolean isReifiable(Type t) {
1694 return isReifiable.visit(t);
1695 }
1696 // where
1697 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1699 public Boolean visitType(Type t, Void ignored) {
1700 return true;
1701 }
1703 @Override
1704 public Boolean visitClassType(ClassType t, Void ignored) {
1705 if (t.isCompound())
1706 return false;
1707 else {
1708 if (!t.isParameterized())
1709 return true;
1711 for (Type param : t.allparams()) {
1712 if (!param.isUnbound())
1713 return false;
1714 }
1715 return true;
1716 }
1717 }
1719 @Override
1720 public Boolean visitArrayType(ArrayType t, Void ignored) {
1721 return visit(t.elemtype);
1722 }
1724 @Override
1725 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1726 return false;
1727 }
1728 };
1729 // </editor-fold>
1731 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1732 public boolean isArray(Type t) {
1733 while (t.tag == WILDCARD)
1734 t = upperBound(t);
1735 return t.tag == ARRAY;
1736 }
1738 /**
1739 * The element type of an array.
1740 */
1741 public Type elemtype(Type t) {
1742 switch (t.tag) {
1743 case WILDCARD:
1744 return elemtype(upperBound(t));
1745 case ARRAY:
1746 t = t.unannotatedType();
1747 return ((ArrayType)t).elemtype;
1748 case FORALL:
1749 return elemtype(((ForAll)t).qtype);
1750 case ERROR:
1751 return t;
1752 default:
1753 return null;
1754 }
1755 }
1757 public Type elemtypeOrType(Type t) {
1758 Type elemtype = elemtype(t);
1759 return elemtype != null ?
1760 elemtype :
1761 t;
1762 }
1764 /**
1765 * Mapping to take element type of an arraytype
1766 */
1767 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1768 public Type apply(Type t) { return elemtype(t); }
1769 };
1771 /**
1772 * The number of dimensions of an array type.
1773 */
1774 public int dimensions(Type t) {
1775 int result = 0;
1776 while (t.tag == ARRAY) {
1777 result++;
1778 t = elemtype(t);
1779 }
1780 return result;
1781 }
1783 /**
1784 * Returns an ArrayType with the component type t
1785 *
1786 * @param t The component type of the ArrayType
1787 * @return the ArrayType for the given component
1788 */
1789 public ArrayType makeArrayType(Type t) {
1790 if (t.tag == VOID ||
1791 t.tag == PACKAGE) {
1792 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
1793 }
1794 return new ArrayType(t, syms.arrayClass);
1795 }
1796 // </editor-fold>
1798 // <editor-fold defaultstate="collapsed" desc="asSuper">
1799 /**
1800 * Return the (most specific) base type of t that starts with the
1801 * given symbol. If none exists, return null.
1802 *
1803 * @param t a type
1804 * @param sym a symbol
1805 */
1806 public Type asSuper(Type t, Symbol sym) {
1807 return asSuper.visit(t, sym);
1808 }
1809 // where
1810 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1812 public Type visitType(Type t, Symbol sym) {
1813 return null;
1814 }
1816 @Override
1817 public Type visitClassType(ClassType t, Symbol sym) {
1818 if (t.tsym == sym)
1819 return t;
1821 Type st = supertype(t);
1822 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1823 Type x = asSuper(st, sym);
1824 if (x != null)
1825 return x;
1826 }
1827 if ((sym.flags() & INTERFACE) != 0) {
1828 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1829 Type x = asSuper(l.head, sym);
1830 if (x != null)
1831 return x;
1832 }
1833 }
1834 return null;
1835 }
1837 @Override
1838 public Type visitArrayType(ArrayType t, Symbol sym) {
1839 return isSubtype(t, sym.type) ? sym.type : null;
1840 }
1842 @Override
1843 public Type visitTypeVar(TypeVar t, Symbol sym) {
1844 if (t.tsym == sym)
1845 return t;
1846 else
1847 return asSuper(t.bound, sym);
1848 }
1850 @Override
1851 public Type visitErrorType(ErrorType t, Symbol sym) {
1852 return t;
1853 }
1854 };
1856 /**
1857 * Return the base type of t or any of its outer types that starts
1858 * with the given symbol. If none exists, return null.
1859 *
1860 * @param t a type
1861 * @param sym a symbol
1862 */
1863 public Type asOuterSuper(Type t, Symbol sym) {
1864 switch (t.tag) {
1865 case CLASS:
1866 do {
1867 Type s = asSuper(t, sym);
1868 if (s != null) return s;
1869 t = t.getEnclosingType();
1870 } while (t.tag == CLASS);
1871 return null;
1872 case ARRAY:
1873 return isSubtype(t, sym.type) ? sym.type : null;
1874 case TYPEVAR:
1875 return asSuper(t, sym);
1876 case ERROR:
1877 return t;
1878 default:
1879 return null;
1880 }
1881 }
1883 /**
1884 * Return the base type of t or any of its enclosing types that
1885 * starts with the given symbol. If none exists, return null.
1886 *
1887 * @param t a type
1888 * @param sym a symbol
1889 */
1890 public Type asEnclosingSuper(Type t, Symbol sym) {
1891 switch (t.tag) {
1892 case CLASS:
1893 do {
1894 Type s = asSuper(t, sym);
1895 if (s != null) return s;
1896 Type outer = t.getEnclosingType();
1897 t = (outer.tag == CLASS) ? outer :
1898 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1899 Type.noType;
1900 } while (t.tag == CLASS);
1901 return null;
1902 case ARRAY:
1903 return isSubtype(t, sym.type) ? sym.type : null;
1904 case TYPEVAR:
1905 return asSuper(t, sym);
1906 case ERROR:
1907 return t;
1908 default:
1909 return null;
1910 }
1911 }
1912 // </editor-fold>
1914 // <editor-fold defaultstate="collapsed" desc="memberType">
1915 /**
1916 * The type of given symbol, seen as a member of t.
1917 *
1918 * @param t a type
1919 * @param sym a symbol
1920 */
1921 public Type memberType(Type t, Symbol sym) {
1922 return (sym.flags() & STATIC) != 0
1923 ? sym.type
1924 : memberType.visit(t, sym);
1925 }
1926 // where
1927 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1929 public Type visitType(Type t, Symbol sym) {
1930 return sym.type;
1931 }
1933 @Override
1934 public Type visitWildcardType(WildcardType t, Symbol sym) {
1935 return memberType(upperBound(t), sym);
1936 }
1938 @Override
1939 public Type visitClassType(ClassType t, Symbol sym) {
1940 Symbol owner = sym.owner;
1941 long flags = sym.flags();
1942 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1943 Type base = asOuterSuper(t, owner);
1944 //if t is an intersection type T = CT & I1 & I2 ... & In
1945 //its supertypes CT, I1, ... In might contain wildcards
1946 //so we need to go through capture conversion
1947 base = t.isCompound() ? capture(base) : base;
1948 if (base != null) {
1949 List<Type> ownerParams = owner.type.allparams();
1950 List<Type> baseParams = base.allparams();
1951 if (ownerParams.nonEmpty()) {
1952 if (baseParams.isEmpty()) {
1953 // then base is a raw type
1954 return erasure(sym.type);
1955 } else {
1956 return subst(sym.type, ownerParams, baseParams);
1957 }
1958 }
1959 }
1960 }
1961 return sym.type;
1962 }
1964 @Override
1965 public Type visitTypeVar(TypeVar t, Symbol sym) {
1966 return memberType(t.bound, sym);
1967 }
1969 @Override
1970 public Type visitErrorType(ErrorType t, Symbol sym) {
1971 return t;
1972 }
1973 };
1974 // </editor-fold>
1976 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1977 public boolean isAssignable(Type t, Type s) {
1978 return isAssignable(t, s, noWarnings);
1979 }
1981 /**
1982 * Is t assignable to s?<br>
1983 * Equivalent to subtype except for constant values and raw
1984 * types.<br>
1985 * (not defined for Method and ForAll types)
1986 */
1987 public boolean isAssignable(Type t, Type s, Warner warn) {
1988 if (t.tag == ERROR)
1989 return true;
1990 if (t.tag.isSubRangeOf(INT) && t.constValue() != null) {
1991 int value = ((Number)t.constValue()).intValue();
1992 switch (s.tag) {
1993 case BYTE:
1994 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1995 return true;
1996 break;
1997 case CHAR:
1998 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1999 return true;
2000 break;
2001 case SHORT:
2002 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
2003 return true;
2004 break;
2005 case INT:
2006 return true;
2007 case CLASS:
2008 switch (unboxedType(s).tag) {
2009 case BYTE:
2010 case CHAR:
2011 case SHORT:
2012 return isAssignable(t, unboxedType(s), warn);
2013 }
2014 break;
2015 }
2016 }
2017 return isConvertible(t, s, warn);
2018 }
2019 // </editor-fold>
2021 // <editor-fold defaultstate="collapsed" desc="erasure">
2022 /**
2023 * The erasure of t {@code |t|} -- the type that results when all
2024 * type parameters in t are deleted.
2025 */
2026 public Type erasure(Type t) {
2027 return eraseNotNeeded(t)? t : erasure(t, false);
2028 }
2029 //where
2030 private boolean eraseNotNeeded(Type t) {
2031 // We don't want to erase primitive types and String type as that
2032 // operation is idempotent. Also, erasing these could result in loss
2033 // of information such as constant values attached to such types.
2034 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
2035 }
2037 private Type erasure(Type t, boolean recurse) {
2038 if (t.isPrimitive())
2039 return t; /* fast special case */
2040 else
2041 return erasure.visit(t, recurse);
2042 }
2043 // where
2044 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
2045 public Type visitType(Type t, Boolean recurse) {
2046 if (t.isPrimitive())
2047 return t; /*fast special case*/
2048 else
2049 return t.map(recurse ? erasureRecFun : erasureFun);
2050 }
2052 @Override
2053 public Type visitWildcardType(WildcardType t, Boolean recurse) {
2054 return erasure(upperBound(t), recurse);
2055 }
2057 @Override
2058 public Type visitClassType(ClassType t, Boolean recurse) {
2059 Type erased = t.tsym.erasure(Types.this);
2060 if (recurse) {
2061 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
2062 }
2063 return erased;
2064 }
2066 @Override
2067 public Type visitTypeVar(TypeVar t, Boolean recurse) {
2068 return erasure(t.bound, recurse);
2069 }
2071 @Override
2072 public Type visitErrorType(ErrorType t, Boolean recurse) {
2073 return t;
2074 }
2076 @Override
2077 public Type visitAnnotatedType(AnnotatedType t, Boolean recurse) {
2078 Type erased = erasure(t.underlyingType, recurse);
2079 if (erased.getKind() == TypeKind.ANNOTATED) {
2080 // This can only happen when the underlying type is a
2081 // type variable and the upper bound of it is annotated.
2082 // The annotation on the type variable overrides the one
2083 // on the bound.
2084 erased = ((AnnotatedType)erased).underlyingType;
2085 }
2086 return new AnnotatedType(t.typeAnnotations, erased);
2087 }
2088 };
2090 private Mapping erasureFun = new Mapping ("erasure") {
2091 public Type apply(Type t) { return erasure(t); }
2092 };
2094 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
2095 public Type apply(Type t) { return erasureRecursive(t); }
2096 };
2098 public List<Type> erasure(List<Type> ts) {
2099 return Type.map(ts, erasureFun);
2100 }
2102 public Type erasureRecursive(Type t) {
2103 return erasure(t, true);
2104 }
2106 public List<Type> erasureRecursive(List<Type> ts) {
2107 return Type.map(ts, erasureRecFun);
2108 }
2109 // </editor-fold>
2111 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
2112 /**
2113 * Make a compound type from non-empty list of types
2114 *
2115 * @param bounds the types from which the compound type is formed
2116 * @param supertype is objectType if all bounds are interfaces,
2117 * null otherwise.
2118 */
2119 public Type makeCompoundType(List<Type> bounds) {
2120 return makeCompoundType(bounds, bounds.head.tsym.isInterface());
2121 }
2122 public Type makeCompoundType(List<Type> bounds, boolean allInterfaces) {
2123 Assert.check(bounds.nonEmpty());
2124 Type firstExplicitBound = bounds.head;
2125 if (allInterfaces) {
2126 bounds = bounds.prepend(syms.objectType);
2127 }
2128 ClassSymbol bc =
2129 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
2130 Type.moreInfo
2131 ? names.fromString(bounds.toString())
2132 : names.empty,
2133 null,
2134 syms.noSymbol);
2135 bc.type = new IntersectionClassType(bounds, bc, allInterfaces);
2136 bc.erasure_field = (bounds.head.tag == TYPEVAR) ?
2137 syms.objectType : // error condition, recover
2138 erasure(firstExplicitBound);
2139 bc.members_field = new Scope(bc);
2140 return bc.type;
2141 }
2143 /**
2144 * A convenience wrapper for {@link #makeCompoundType(List)}; the
2145 * arguments are converted to a list and passed to the other
2146 * method. Note that this might cause a symbol completion.
2147 * Hence, this version of makeCompoundType may not be called
2148 * during a classfile read.
2149 */
2150 public Type makeCompoundType(Type bound1, Type bound2) {
2151 return makeCompoundType(List.of(bound1, bound2));
2152 }
2153 // </editor-fold>
2155 // <editor-fold defaultstate="collapsed" desc="supertype">
2156 public Type supertype(Type t) {
2157 return supertype.visit(t);
2158 }
2159 // where
2160 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2162 public Type visitType(Type t, Void ignored) {
2163 // A note on wildcards: there is no good way to
2164 // determine a supertype for a super bounded wildcard.
2165 return null;
2166 }
2168 @Override
2169 public Type visitClassType(ClassType t, Void ignored) {
2170 if (t.supertype_field == null) {
2171 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2172 // An interface has no superclass; its supertype is Object.
2173 if (t.isInterface())
2174 supertype = ((ClassType)t.tsym.type).supertype_field;
2175 if (t.supertype_field == null) {
2176 List<Type> actuals = classBound(t).allparams();
2177 List<Type> formals = t.tsym.type.allparams();
2178 if (t.hasErasedSupertypes()) {
2179 t.supertype_field = erasureRecursive(supertype);
2180 } else if (formals.nonEmpty()) {
2181 t.supertype_field = subst(supertype, formals, actuals);
2182 }
2183 else {
2184 t.supertype_field = supertype;
2185 }
2186 }
2187 }
2188 return t.supertype_field;
2189 }
2191 /**
2192 * The supertype is always a class type. If the type
2193 * variable's bounds start with a class type, this is also
2194 * the supertype. Otherwise, the supertype is
2195 * java.lang.Object.
2196 */
2197 @Override
2198 public Type visitTypeVar(TypeVar t, Void ignored) {
2199 if (t.bound.tag == TYPEVAR ||
2200 (!t.bound.isCompound() && !t.bound.isInterface())) {
2201 return t.bound;
2202 } else {
2203 return supertype(t.bound);
2204 }
2205 }
2207 @Override
2208 public Type visitArrayType(ArrayType t, Void ignored) {
2209 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2210 return arraySuperType();
2211 else
2212 return new ArrayType(supertype(t.elemtype), t.tsym);
2213 }
2215 @Override
2216 public Type visitErrorType(ErrorType t, Void ignored) {
2217 return t;
2218 }
2219 };
2220 // </editor-fold>
2222 // <editor-fold defaultstate="collapsed" desc="interfaces">
2223 /**
2224 * Return the interfaces implemented by this class.
2225 */
2226 public List<Type> interfaces(Type t) {
2227 return interfaces.visit(t);
2228 }
2229 // where
2230 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2232 public List<Type> visitType(Type t, Void ignored) {
2233 return List.nil();
2234 }
2236 @Override
2237 public List<Type> visitClassType(ClassType t, Void ignored) {
2238 if (t.interfaces_field == null) {
2239 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2240 if (t.interfaces_field == null) {
2241 // If t.interfaces_field is null, then t must
2242 // be a parameterized type (not to be confused
2243 // with a generic type declaration).
2244 // Terminology:
2245 // Parameterized type: List<String>
2246 // Generic type declaration: class List<E> { ... }
2247 // So t corresponds to List<String> and
2248 // t.tsym.type corresponds to List<E>.
2249 // The reason t must be parameterized type is
2250 // that completion will happen as a side
2251 // effect of calling
2252 // ClassSymbol.getInterfaces. Since
2253 // t.interfaces_field is null after
2254 // completion, we can assume that t is not the
2255 // type of a class/interface declaration.
2256 Assert.check(t != t.tsym.type, t);
2257 List<Type> actuals = t.allparams();
2258 List<Type> formals = t.tsym.type.allparams();
2259 if (t.hasErasedSupertypes()) {
2260 t.interfaces_field = erasureRecursive(interfaces);
2261 } else if (formals.nonEmpty()) {
2262 t.interfaces_field =
2263 upperBounds(subst(interfaces, formals, actuals));
2264 }
2265 else {
2266 t.interfaces_field = interfaces;
2267 }
2268 }
2269 }
2270 return t.interfaces_field;
2271 }
2273 @Override
2274 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2275 if (t.bound.isCompound())
2276 return interfaces(t.bound);
2278 if (t.bound.isInterface())
2279 return List.of(t.bound);
2281 return List.nil();
2282 }
2283 };
2285 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2286 for (Type i2 : interfaces(origin.type)) {
2287 if (isym == i2.tsym) return true;
2288 }
2289 return false;
2290 }
2291 // </editor-fold>
2293 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2294 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
2296 public boolean isDerivedRaw(Type t) {
2297 Boolean result = isDerivedRawCache.get(t);
2298 if (result == null) {
2299 result = isDerivedRawInternal(t);
2300 isDerivedRawCache.put(t, result);
2301 }
2302 return result;
2303 }
2305 public boolean isDerivedRawInternal(Type t) {
2306 if (t.isErroneous())
2307 return false;
2308 return
2309 t.isRaw() ||
2310 supertype(t) != null && isDerivedRaw(supertype(t)) ||
2311 isDerivedRaw(interfaces(t));
2312 }
2314 public boolean isDerivedRaw(List<Type> ts) {
2315 List<Type> l = ts;
2316 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2317 return l.nonEmpty();
2318 }
2319 // </editor-fold>
2321 // <editor-fold defaultstate="collapsed" desc="setBounds">
2322 /**
2323 * Set the bounds field of the given type variable to reflect a
2324 * (possibly multiple) list of bounds.
2325 * @param t a type variable
2326 * @param bounds the bounds, must be nonempty
2327 * @param supertype is objectType if all bounds are interfaces,
2328 * null otherwise.
2329 */
2330 public void setBounds(TypeVar t, List<Type> bounds) {
2331 setBounds(t, bounds, bounds.head.tsym.isInterface());
2332 }
2334 /**
2335 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
2336 * third parameter is computed directly, as follows: if all
2337 * all bounds are interface types, the computed supertype is Object,
2338 * otherwise the supertype is simply left null (in this case, the supertype
2339 * is assumed to be the head of the bound list passed as second argument).
2340 * Note that this check might cause a symbol completion. Hence, this version of
2341 * setBounds may not be called during a classfile read.
2342 */
2343 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
2344 t.bound = bounds.tail.isEmpty() ?
2345 bounds.head :
2346 makeCompoundType(bounds, allInterfaces);
2347 t.rank_field = -1;
2348 }
2349 // </editor-fold>
2351 // <editor-fold defaultstate="collapsed" desc="getBounds">
2352 /**
2353 * Return list of bounds of the given type variable.
2354 */
2355 public List<Type> getBounds(TypeVar t) {
2356 if (t.bound.hasTag(NONE))
2357 return List.nil();
2358 else if (t.bound.isErroneous() || !t.bound.isCompound())
2359 return List.of(t.bound);
2360 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2361 return interfaces(t).prepend(supertype(t));
2362 else
2363 // No superclass was given in bounds.
2364 // In this case, supertype is Object, erasure is first interface.
2365 return interfaces(t);
2366 }
2367 // </editor-fold>
2369 // <editor-fold defaultstate="collapsed" desc="classBound">
2370 /**
2371 * If the given type is a (possibly selected) type variable,
2372 * return the bounding class of this type, otherwise return the
2373 * type itself.
2374 */
2375 public Type classBound(Type t) {
2376 return classBound.visit(t);
2377 }
2378 // where
2379 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2381 public Type visitType(Type t, Void ignored) {
2382 return t;
2383 }
2385 @Override
2386 public Type visitClassType(ClassType t, Void ignored) {
2387 Type outer1 = classBound(t.getEnclosingType());
2388 if (outer1 != t.getEnclosingType())
2389 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
2390 else
2391 return t;
2392 }
2394 @Override
2395 public Type visitTypeVar(TypeVar t, Void ignored) {
2396 return classBound(supertype(t));
2397 }
2399 @Override
2400 public Type visitErrorType(ErrorType t, Void ignored) {
2401 return t;
2402 }
2403 };
2404 // </editor-fold>
2406 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
2407 /**
2408 * Returns true iff the first signature is a <em>sub
2409 * signature</em> of the other. This is <b>not</b> an equivalence
2410 * relation.
2411 *
2412 * @jls section 8.4.2.
2413 * @see #overrideEquivalent(Type t, Type s)
2414 * @param t first signature (possibly raw).
2415 * @param s second signature (could be subjected to erasure).
2416 * @return true if t is a sub signature of s.
2417 */
2418 public boolean isSubSignature(Type t, Type s) {
2419 return isSubSignature(t, s, true);
2420 }
2422 public boolean isSubSignature(Type t, Type s, boolean strict) {
2423 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2424 }
2426 /**
2427 * Returns true iff these signatures are related by <em>override
2428 * equivalence</em>. This is the natural extension of
2429 * isSubSignature to an equivalence relation.
2430 *
2431 * @jls section 8.4.2.
2432 * @see #isSubSignature(Type t, Type s)
2433 * @param t a signature (possible raw, could be subjected to
2434 * erasure).
2435 * @param s a signature (possible raw, could be subjected to
2436 * erasure).
2437 * @return true if either argument is a sub signature of the other.
2438 */
2439 public boolean overrideEquivalent(Type t, Type s) {
2440 return hasSameArgs(t, s) ||
2441 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2442 }
2444 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2445 for (Scope.Entry e = syms.objectType.tsym.members().lookup(msym.name) ; e.scope != null ; e = e.next()) {
2446 if (msym.overrides(e.sym, origin, Types.this, true)) {
2447 return true;
2448 }
2449 }
2450 return false;
2451 }
2453 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2454 class ImplementationCache {
2456 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
2457 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
2459 class Entry {
2460 final MethodSymbol cachedImpl;
2461 final Filter<Symbol> implFilter;
2462 final boolean checkResult;
2463 final int prevMark;
2465 public Entry(MethodSymbol cachedImpl,
2466 Filter<Symbol> scopeFilter,
2467 boolean checkResult,
2468 int prevMark) {
2469 this.cachedImpl = cachedImpl;
2470 this.implFilter = scopeFilter;
2471 this.checkResult = checkResult;
2472 this.prevMark = prevMark;
2473 }
2475 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
2476 return this.implFilter == scopeFilter &&
2477 this.checkResult == checkResult &&
2478 this.prevMark == mark;
2479 }
2480 }
2482 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2483 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2484 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2485 if (cache == null) {
2486 cache = new HashMap<TypeSymbol, Entry>();
2487 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2488 }
2489 Entry e = cache.get(origin);
2490 CompoundScope members = membersClosure(origin.type, true);
2491 if (e == null ||
2492 !e.matches(implFilter, checkResult, members.getMark())) {
2493 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2494 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2495 return impl;
2496 }
2497 else {
2498 return e.cachedImpl;
2499 }
2500 }
2502 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2503 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = supertype(t)) {
2504 while (t.tag == TYPEVAR)
2505 t = t.getUpperBound();
2506 TypeSymbol c = t.tsym;
2507 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2508 e.scope != null;
2509 e = e.next(implFilter)) {
2510 if (e.sym != null &&
2511 e.sym.overrides(ms, origin, Types.this, checkResult))
2512 return (MethodSymbol)e.sym;
2513 }
2514 }
2515 return null;
2516 }
2517 }
2519 private ImplementationCache implCache = new ImplementationCache();
2521 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2522 return implCache.get(ms, origin, checkResult, implFilter);
2523 }
2524 // </editor-fold>
2526 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2527 class MembersClosureCache extends SimpleVisitor<CompoundScope, Boolean> {
2529 private WeakHashMap<TypeSymbol, Entry> _map =
2530 new WeakHashMap<TypeSymbol, Entry>();
2532 class Entry {
2533 final boolean skipInterfaces;
2534 final CompoundScope compoundScope;
2536 public Entry(boolean skipInterfaces, CompoundScope compoundScope) {
2537 this.skipInterfaces = skipInterfaces;
2538 this.compoundScope = compoundScope;
2539 }
2541 boolean matches(boolean skipInterfaces) {
2542 return this.skipInterfaces == skipInterfaces;
2543 }
2544 }
2546 List<TypeSymbol> seenTypes = List.nil();
2548 /** members closure visitor methods **/
2550 public CompoundScope visitType(Type t, Boolean skipInterface) {
2551 return null;
2552 }
2554 @Override
2555 public CompoundScope visitClassType(ClassType t, Boolean skipInterface) {
2556 if (seenTypes.contains(t.tsym)) {
2557 //this is possible when an interface is implemented in multiple
2558 //superclasses, or when a classs hierarchy is circular - in such
2559 //cases we don't need to recurse (empty scope is returned)
2560 return new CompoundScope(t.tsym);
2561 }
2562 try {
2563 seenTypes = seenTypes.prepend(t.tsym);
2564 ClassSymbol csym = (ClassSymbol)t.tsym;
2565 Entry e = _map.get(csym);
2566 if (e == null || !e.matches(skipInterface)) {
2567 CompoundScope membersClosure = new CompoundScope(csym);
2568 if (!skipInterface) {
2569 for (Type i : interfaces(t)) {
2570 membersClosure.addSubScope(visit(i, skipInterface));
2571 }
2572 }
2573 membersClosure.addSubScope(visit(supertype(t), skipInterface));
2574 membersClosure.addSubScope(csym.members());
2575 e = new Entry(skipInterface, membersClosure);
2576 _map.put(csym, e);
2577 }
2578 return e.compoundScope;
2579 }
2580 finally {
2581 seenTypes = seenTypes.tail;
2582 }
2583 }
2585 @Override
2586 public CompoundScope visitTypeVar(TypeVar t, Boolean skipInterface) {
2587 return visit(t.getUpperBound(), skipInterface);
2588 }
2589 }
2591 private MembersClosureCache membersCache = new MembersClosureCache();
2593 public CompoundScope membersClosure(Type site, boolean skipInterface) {
2594 return membersCache.visit(site, skipInterface);
2595 }
2596 // </editor-fold>
2599 //where
2600 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
2601 Filter<Symbol> filter = new MethodFilter(ms, site);
2602 List<MethodSymbol> candidates = List.nil();
2603 for (Symbol s : membersClosure(site, false).getElements(filter)) {
2604 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
2605 return List.of((MethodSymbol)s);
2606 } else if (!candidates.contains(s)) {
2607 candidates = candidates.prepend((MethodSymbol)s);
2608 }
2609 }
2610 return prune(candidates);
2611 }
2613 public List<MethodSymbol> prune(List<MethodSymbol> methods) {
2614 ListBuffer<MethodSymbol> methodsMin = ListBuffer.lb();
2615 for (MethodSymbol m1 : methods) {
2616 boolean isMin_m1 = true;
2617 for (MethodSymbol m2 : methods) {
2618 if (m1 == m2) continue;
2619 if (m2.owner != m1.owner &&
2620 asSuper(m2.owner.type, m1.owner) != null) {
2621 isMin_m1 = false;
2622 break;
2623 }
2624 }
2625 if (isMin_m1)
2626 methodsMin.append(m1);
2627 }
2628 return methodsMin.toList();
2629 }
2630 // where
2631 private class MethodFilter implements Filter<Symbol> {
2633 Symbol msym;
2634 Type site;
2636 MethodFilter(Symbol msym, Type site) {
2637 this.msym = msym;
2638 this.site = site;
2639 }
2641 public boolean accepts(Symbol s) {
2642 return s.kind == Kinds.MTH &&
2643 s.name == msym.name &&
2644 s.isInheritedIn(site.tsym, Types.this) &&
2645 overrideEquivalent(memberType(site, s), memberType(site, msym));
2646 }
2647 };
2648 // </editor-fold>
2650 /**
2651 * Does t have the same arguments as s? It is assumed that both
2652 * types are (possibly polymorphic) method types. Monomorphic
2653 * method types "have the same arguments", if their argument lists
2654 * are equal. Polymorphic method types "have the same arguments",
2655 * if they have the same arguments after renaming all type
2656 * variables of one to corresponding type variables in the other,
2657 * where correspondence is by position in the type parameter list.
2658 */
2659 public boolean hasSameArgs(Type t, Type s) {
2660 return hasSameArgs(t, s, true);
2661 }
2663 public boolean hasSameArgs(Type t, Type s, boolean strict) {
2664 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
2665 }
2667 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
2668 return hasSameArgs.visit(t, s);
2669 }
2670 // where
2671 private class HasSameArgs extends TypeRelation {
2673 boolean strict;
2675 public HasSameArgs(boolean strict) {
2676 this.strict = strict;
2677 }
2679 public Boolean visitType(Type t, Type s) {
2680 throw new AssertionError();
2681 }
2683 @Override
2684 public Boolean visitMethodType(MethodType t, Type s) {
2685 return s.tag == METHOD
2686 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2687 }
2689 @Override
2690 public Boolean visitForAll(ForAll t, Type s) {
2691 if (s.tag != FORALL)
2692 return strict ? false : visitMethodType(t.asMethodType(), s);
2694 ForAll forAll = (ForAll)s;
2695 return hasSameBounds(t, forAll)
2696 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2697 }
2699 @Override
2700 public Boolean visitErrorType(ErrorType t, Type s) {
2701 return false;
2702 }
2703 };
2705 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
2706 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
2708 // </editor-fold>
2710 // <editor-fold defaultstate="collapsed" desc="subst">
2711 public List<Type> subst(List<Type> ts,
2712 List<Type> from,
2713 List<Type> to) {
2714 return new Subst(from, to).subst(ts);
2715 }
2717 /**
2718 * Substitute all occurrences of a type in `from' with the
2719 * corresponding type in `to' in 't'. Match lists `from' and `to'
2720 * from the right: If lists have different length, discard leading
2721 * elements of the longer list.
2722 */
2723 public Type subst(Type t, List<Type> from, List<Type> to) {
2724 return new Subst(from, to).subst(t);
2725 }
2727 private class Subst extends UnaryVisitor<Type> {
2728 List<Type> from;
2729 List<Type> to;
2731 public Subst(List<Type> from, List<Type> to) {
2732 int fromLength = from.length();
2733 int toLength = to.length();
2734 while (fromLength > toLength) {
2735 fromLength--;
2736 from = from.tail;
2737 }
2738 while (fromLength < toLength) {
2739 toLength--;
2740 to = to.tail;
2741 }
2742 this.from = from;
2743 this.to = to;
2744 }
2746 Type subst(Type t) {
2747 if (from.tail == null)
2748 return t;
2749 else
2750 return visit(t);
2751 }
2753 List<Type> subst(List<Type> ts) {
2754 if (from.tail == null)
2755 return ts;
2756 boolean wild = false;
2757 if (ts.nonEmpty() && from.nonEmpty()) {
2758 Type head1 = subst(ts.head);
2759 List<Type> tail1 = subst(ts.tail);
2760 if (head1 != ts.head || tail1 != ts.tail)
2761 return tail1.prepend(head1);
2762 }
2763 return ts;
2764 }
2766 public Type visitType(Type t, Void ignored) {
2767 return t;
2768 }
2770 @Override
2771 public Type visitMethodType(MethodType t, Void ignored) {
2772 List<Type> argtypes = subst(t.argtypes);
2773 Type restype = subst(t.restype);
2774 List<Type> thrown = subst(t.thrown);
2775 if (argtypes == t.argtypes &&
2776 restype == t.restype &&
2777 thrown == t.thrown)
2778 return t;
2779 else
2780 return new MethodType(argtypes, restype, thrown, t.tsym);
2781 }
2783 @Override
2784 public Type visitTypeVar(TypeVar t, Void ignored) {
2785 for (List<Type> from = this.from, to = this.to;
2786 from.nonEmpty();
2787 from = from.tail, to = to.tail) {
2788 if (t == from.head) {
2789 return to.head.withTypeVar(t);
2790 }
2791 }
2792 return t;
2793 }
2795 @Override
2796 public Type visitClassType(ClassType t, Void ignored) {
2797 if (!t.isCompound()) {
2798 List<Type> typarams = t.getTypeArguments();
2799 List<Type> typarams1 = subst(typarams);
2800 Type outer = t.getEnclosingType();
2801 Type outer1 = subst(outer);
2802 if (typarams1 == typarams && outer1 == outer)
2803 return t;
2804 else
2805 return new ClassType(outer1, typarams1, t.tsym);
2806 } else {
2807 Type st = subst(supertype(t));
2808 List<Type> is = upperBounds(subst(interfaces(t)));
2809 if (st == supertype(t) && is == interfaces(t))
2810 return t;
2811 else
2812 return makeCompoundType(is.prepend(st));
2813 }
2814 }
2816 @Override
2817 public Type visitWildcardType(WildcardType t, Void ignored) {
2818 Type bound = t.type;
2819 if (t.kind != BoundKind.UNBOUND)
2820 bound = subst(bound);
2821 if (bound == t.type) {
2822 return t;
2823 } else {
2824 if (t.isExtendsBound() && bound.isExtendsBound())
2825 bound = upperBound(bound);
2826 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2827 }
2828 }
2830 @Override
2831 public Type visitArrayType(ArrayType t, Void ignored) {
2832 Type elemtype = subst(t.elemtype);
2833 if (elemtype == t.elemtype)
2834 return t;
2835 else
2836 return new ArrayType(upperBound(elemtype), t.tsym);
2837 }
2839 @Override
2840 public Type visitForAll(ForAll t, Void ignored) {
2841 if (Type.containsAny(to, t.tvars)) {
2842 //perform alpha-renaming of free-variables in 't'
2843 //if 'to' types contain variables that are free in 't'
2844 List<Type> freevars = newInstances(t.tvars);
2845 t = new ForAll(freevars,
2846 Types.this.subst(t.qtype, t.tvars, freevars));
2847 }
2848 List<Type> tvars1 = substBounds(t.tvars, from, to);
2849 Type qtype1 = subst(t.qtype);
2850 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2851 return t;
2852 } else if (tvars1 == t.tvars) {
2853 return new ForAll(tvars1, qtype1);
2854 } else {
2855 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2856 }
2857 }
2859 @Override
2860 public Type visitErrorType(ErrorType t, Void ignored) {
2861 return t;
2862 }
2863 }
2865 public List<Type> substBounds(List<Type> tvars,
2866 List<Type> from,
2867 List<Type> to) {
2868 if (tvars.isEmpty())
2869 return tvars;
2870 ListBuffer<Type> newBoundsBuf = lb();
2871 boolean changed = false;
2872 // calculate new bounds
2873 for (Type t : tvars) {
2874 TypeVar tv = (TypeVar) t;
2875 Type bound = subst(tv.bound, from, to);
2876 if (bound != tv.bound)
2877 changed = true;
2878 newBoundsBuf.append(bound);
2879 }
2880 if (!changed)
2881 return tvars;
2882 ListBuffer<Type> newTvars = lb();
2883 // create new type variables without bounds
2884 for (Type t : tvars) {
2885 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2886 }
2887 // the new bounds should use the new type variables in place
2888 // of the old
2889 List<Type> newBounds = newBoundsBuf.toList();
2890 from = tvars;
2891 to = newTvars.toList();
2892 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2893 newBounds.head = subst(newBounds.head, from, to);
2894 }
2895 newBounds = newBoundsBuf.toList();
2896 // set the bounds of new type variables to the new bounds
2897 for (Type t : newTvars.toList()) {
2898 TypeVar tv = (TypeVar) t;
2899 tv.bound = newBounds.head;
2900 newBounds = newBounds.tail;
2901 }
2902 return newTvars.toList();
2903 }
2905 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2906 Type bound1 = subst(t.bound, from, to);
2907 if (bound1 == t.bound)
2908 return t;
2909 else {
2910 // create new type variable without bounds
2911 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2912 // the new bound should use the new type variable in place
2913 // of the old
2914 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2915 return tv;
2916 }
2917 }
2918 // </editor-fold>
2920 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2921 /**
2922 * Does t have the same bounds for quantified variables as s?
2923 */
2924 boolean hasSameBounds(ForAll t, ForAll s) {
2925 List<Type> l1 = t.tvars;
2926 List<Type> l2 = s.tvars;
2927 while (l1.nonEmpty() && l2.nonEmpty() &&
2928 isSameType(l1.head.getUpperBound(),
2929 subst(l2.head.getUpperBound(),
2930 s.tvars,
2931 t.tvars))) {
2932 l1 = l1.tail;
2933 l2 = l2.tail;
2934 }
2935 return l1.isEmpty() && l2.isEmpty();
2936 }
2937 // </editor-fold>
2939 // <editor-fold defaultstate="collapsed" desc="newInstances">
2940 /** Create new vector of type variables from list of variables
2941 * changing all recursive bounds from old to new list.
2942 */
2943 public List<Type> newInstances(List<Type> tvars) {
2944 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2945 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2946 TypeVar tv = (TypeVar) l.head;
2947 tv.bound = subst(tv.bound, tvars, tvars1);
2948 }
2949 return tvars1;
2950 }
2951 private static final Mapping newInstanceFun = new Mapping("newInstanceFun") {
2952 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2953 };
2954 // </editor-fold>
2956 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
2957 return original.accept(methodWithParameters, newParams);
2958 }
2959 // where
2960 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
2961 public Type visitType(Type t, List<Type> newParams) {
2962 throw new IllegalArgumentException("Not a method type: " + t);
2963 }
2964 public Type visitMethodType(MethodType t, List<Type> newParams) {
2965 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
2966 }
2967 public Type visitForAll(ForAll t, List<Type> newParams) {
2968 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
2969 }
2970 };
2972 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
2973 return original.accept(methodWithThrown, newThrown);
2974 }
2975 // where
2976 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
2977 public Type visitType(Type t, List<Type> newThrown) {
2978 throw new IllegalArgumentException("Not a method type: " + t);
2979 }
2980 public Type visitMethodType(MethodType t, List<Type> newThrown) {
2981 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
2982 }
2983 public Type visitForAll(ForAll t, List<Type> newThrown) {
2984 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
2985 }
2986 };
2988 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
2989 return original.accept(methodWithReturn, newReturn);
2990 }
2991 // where
2992 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
2993 public Type visitType(Type t, Type newReturn) {
2994 throw new IllegalArgumentException("Not a method type: " + t);
2995 }
2996 public Type visitMethodType(MethodType t, Type newReturn) {
2997 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym);
2998 }
2999 public Type visitForAll(ForAll t, Type newReturn) {
3000 return new ForAll(t.tvars, t.qtype.accept(this, newReturn));
3001 }
3002 };
3004 // <editor-fold defaultstate="collapsed" desc="createErrorType">
3005 public Type createErrorType(Type originalType) {
3006 return new ErrorType(originalType, syms.errSymbol);
3007 }
3009 public Type createErrorType(ClassSymbol c, Type originalType) {
3010 return new ErrorType(c, originalType);
3011 }
3013 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
3014 return new ErrorType(name, container, originalType);
3015 }
3016 // </editor-fold>
3018 // <editor-fold defaultstate="collapsed" desc="rank">
3019 /**
3020 * The rank of a class is the length of the longest path between
3021 * the class and java.lang.Object in the class inheritance
3022 * graph. Undefined for all but reference types.
3023 */
3024 public int rank(Type t) {
3025 t = t.unannotatedType();
3026 switch(t.tag) {
3027 case CLASS: {
3028 ClassType cls = (ClassType)t;
3029 if (cls.rank_field < 0) {
3030 Name fullname = cls.tsym.getQualifiedName();
3031 if (fullname == names.java_lang_Object)
3032 cls.rank_field = 0;
3033 else {
3034 int r = rank(supertype(cls));
3035 for (List<Type> l = interfaces(cls);
3036 l.nonEmpty();
3037 l = l.tail) {
3038 if (rank(l.head) > r)
3039 r = rank(l.head);
3040 }
3041 cls.rank_field = r + 1;
3042 }
3043 }
3044 return cls.rank_field;
3045 }
3046 case TYPEVAR: {
3047 TypeVar tvar = (TypeVar)t;
3048 if (tvar.rank_field < 0) {
3049 int r = rank(supertype(tvar));
3050 for (List<Type> l = interfaces(tvar);
3051 l.nonEmpty();
3052 l = l.tail) {
3053 if (rank(l.head) > r) r = rank(l.head);
3054 }
3055 tvar.rank_field = r + 1;
3056 }
3057 return tvar.rank_field;
3058 }
3059 case ERROR:
3060 return 0;
3061 default:
3062 throw new AssertionError();
3063 }
3064 }
3065 // </editor-fold>
3067 /**
3068 * Helper method for generating a string representation of a given type
3069 * accordingly to a given locale
3070 */
3071 public String toString(Type t, Locale locale) {
3072 return Printer.createStandardPrinter(messages).visit(t, locale);
3073 }
3075 /**
3076 * Helper method for generating a string representation of a given type
3077 * accordingly to a given locale
3078 */
3079 public String toString(Symbol t, Locale locale) {
3080 return Printer.createStandardPrinter(messages).visit(t, locale);
3081 }
3083 // <editor-fold defaultstate="collapsed" desc="toString">
3084 /**
3085 * This toString is slightly more descriptive than the one on Type.
3086 *
3087 * @deprecated Types.toString(Type t, Locale l) provides better support
3088 * for localization
3089 */
3090 @Deprecated
3091 public String toString(Type t) {
3092 if (t.tag == FORALL) {
3093 ForAll forAll = (ForAll)t;
3094 return typaramsString(forAll.tvars) + forAll.qtype;
3095 }
3096 return "" + t;
3097 }
3098 // where
3099 private String typaramsString(List<Type> tvars) {
3100 StringBuilder s = new StringBuilder();
3101 s.append('<');
3102 boolean first = true;
3103 for (Type t : tvars) {
3104 if (!first) s.append(", ");
3105 first = false;
3106 appendTyparamString(((TypeVar)t), s);
3107 }
3108 s.append('>');
3109 return s.toString();
3110 }
3111 private void appendTyparamString(TypeVar t, StringBuilder buf) {
3112 buf.append(t);
3113 if (t.bound == null ||
3114 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
3115 return;
3116 buf.append(" extends "); // Java syntax; no need for i18n
3117 Type bound = t.bound;
3118 if (!bound.isCompound()) {
3119 buf.append(bound);
3120 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3121 buf.append(supertype(t));
3122 for (Type intf : interfaces(t)) {
3123 buf.append('&');
3124 buf.append(intf);
3125 }
3126 } else {
3127 // No superclass was given in bounds.
3128 // In this case, supertype is Object, erasure is first interface.
3129 boolean first = true;
3130 for (Type intf : interfaces(t)) {
3131 if (!first) buf.append('&');
3132 first = false;
3133 buf.append(intf);
3134 }
3135 }
3136 }
3137 // </editor-fold>
3139 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3140 /**
3141 * A cache for closures.
3142 *
3143 * <p>A closure is a list of all the supertypes and interfaces of
3144 * a class or interface type, ordered by ClassSymbol.precedes
3145 * (that is, subclasses come first, arbitrary but fixed
3146 * otherwise).
3147 */
3148 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
3150 /**
3151 * Returns the closure of a class or interface type.
3152 */
3153 public List<Type> closure(Type t) {
3154 List<Type> cl = closureCache.get(t);
3155 if (cl == null) {
3156 Type st = supertype(t);
3157 if (!t.isCompound()) {
3158 if (st.tag == CLASS) {
3159 cl = insert(closure(st), t);
3160 } else if (st.tag == TYPEVAR) {
3161 cl = closure(st).prepend(t);
3162 } else {
3163 cl = List.of(t);
3164 }
3165 } else {
3166 cl = closure(supertype(t));
3167 }
3168 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3169 cl = union(cl, closure(l.head));
3170 closureCache.put(t, cl);
3171 }
3172 return cl;
3173 }
3175 /**
3176 * Insert a type in a closure
3177 */
3178 public List<Type> insert(List<Type> cl, Type t) {
3179 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
3180 return cl.prepend(t);
3181 } else if (cl.head.tsym.precedes(t.tsym, this)) {
3182 return insert(cl.tail, t).prepend(cl.head);
3183 } else {
3184 return cl;
3185 }
3186 }
3188 /**
3189 * Form the union of two closures
3190 */
3191 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3192 if (cl1.isEmpty()) {
3193 return cl2;
3194 } else if (cl2.isEmpty()) {
3195 return cl1;
3196 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
3197 return union(cl1.tail, cl2).prepend(cl1.head);
3198 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3199 return union(cl1, cl2.tail).prepend(cl2.head);
3200 } else {
3201 return union(cl1.tail, cl2.tail).prepend(cl1.head);
3202 }
3203 }
3205 /**
3206 * Intersect two closures
3207 */
3208 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3209 if (cl1 == cl2)
3210 return cl1;
3211 if (cl1.isEmpty() || cl2.isEmpty())
3212 return List.nil();
3213 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3214 return intersect(cl1.tail, cl2);
3215 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3216 return intersect(cl1, cl2.tail);
3217 if (isSameType(cl1.head, cl2.head))
3218 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3219 if (cl1.head.tsym == cl2.head.tsym &&
3220 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
3221 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3222 Type merge = merge(cl1.head,cl2.head);
3223 return intersect(cl1.tail, cl2.tail).prepend(merge);
3224 }
3225 if (cl1.head.isRaw() || cl2.head.isRaw())
3226 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3227 }
3228 return intersect(cl1.tail, cl2.tail);
3229 }
3230 // where
3231 class TypePair {
3232 final Type t1;
3233 final Type t2;
3234 TypePair(Type t1, Type t2) {
3235 this.t1 = t1;
3236 this.t2 = t2;
3237 }
3238 @Override
3239 public int hashCode() {
3240 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
3241 }
3242 @Override
3243 public boolean equals(Object obj) {
3244 if (!(obj instanceof TypePair))
3245 return false;
3246 TypePair typePair = (TypePair)obj;
3247 return isSameType(t1, typePair.t1)
3248 && isSameType(t2, typePair.t2);
3249 }
3250 }
3251 Set<TypePair> mergeCache = new HashSet<TypePair>();
3252 private Type merge(Type c1, Type c2) {
3253 ClassType class1 = (ClassType) c1;
3254 List<Type> act1 = class1.getTypeArguments();
3255 ClassType class2 = (ClassType) c2;
3256 List<Type> act2 = class2.getTypeArguments();
3257 ListBuffer<Type> merged = new ListBuffer<Type>();
3258 List<Type> typarams = class1.tsym.type.getTypeArguments();
3260 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3261 if (containsType(act1.head, act2.head)) {
3262 merged.append(act1.head);
3263 } else if (containsType(act2.head, act1.head)) {
3264 merged.append(act2.head);
3265 } else {
3266 TypePair pair = new TypePair(c1, c2);
3267 Type m;
3268 if (mergeCache.add(pair)) {
3269 m = new WildcardType(lub(upperBound(act1.head),
3270 upperBound(act2.head)),
3271 BoundKind.EXTENDS,
3272 syms.boundClass);
3273 mergeCache.remove(pair);
3274 } else {
3275 m = new WildcardType(syms.objectType,
3276 BoundKind.UNBOUND,
3277 syms.boundClass);
3278 }
3279 merged.append(m.withTypeVar(typarams.head));
3280 }
3281 act1 = act1.tail;
3282 act2 = act2.tail;
3283 typarams = typarams.tail;
3284 }
3285 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3286 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
3287 }
3289 /**
3290 * Return the minimum type of a closure, a compound type if no
3291 * unique minimum exists.
3292 */
3293 private Type compoundMin(List<Type> cl) {
3294 if (cl.isEmpty()) return syms.objectType;
3295 List<Type> compound = closureMin(cl);
3296 if (compound.isEmpty())
3297 return null;
3298 else if (compound.tail.isEmpty())
3299 return compound.head;
3300 else
3301 return makeCompoundType(compound);
3302 }
3304 /**
3305 * Return the minimum types of a closure, suitable for computing
3306 * compoundMin or glb.
3307 */
3308 private List<Type> closureMin(List<Type> cl) {
3309 ListBuffer<Type> classes = lb();
3310 ListBuffer<Type> interfaces = lb();
3311 while (!cl.isEmpty()) {
3312 Type current = cl.head;
3313 if (current.isInterface())
3314 interfaces.append(current);
3315 else
3316 classes.append(current);
3317 ListBuffer<Type> candidates = lb();
3318 for (Type t : cl.tail) {
3319 if (!isSubtypeNoCapture(current, t))
3320 candidates.append(t);
3321 }
3322 cl = candidates.toList();
3323 }
3324 return classes.appendList(interfaces).toList();
3325 }
3327 /**
3328 * Return the least upper bound of pair of types. if the lub does
3329 * not exist return null.
3330 */
3331 public Type lub(Type t1, Type t2) {
3332 return lub(List.of(t1, t2));
3333 }
3335 /**
3336 * Return the least upper bound (lub) of set of types. If the lub
3337 * does not exist return the type of null (bottom).
3338 */
3339 public Type lub(List<Type> ts) {
3340 final int ARRAY_BOUND = 1;
3341 final int CLASS_BOUND = 2;
3342 int boundkind = 0;
3343 for (Type t : ts) {
3344 switch (t.tag) {
3345 case CLASS:
3346 boundkind |= CLASS_BOUND;
3347 break;
3348 case ARRAY:
3349 boundkind |= ARRAY_BOUND;
3350 break;
3351 case TYPEVAR:
3352 do {
3353 t = t.getUpperBound();
3354 } while (t.tag == TYPEVAR);
3355 if (t.tag == ARRAY) {
3356 boundkind |= ARRAY_BOUND;
3357 } else {
3358 boundkind |= CLASS_BOUND;
3359 }
3360 break;
3361 default:
3362 if (t.isPrimitive())
3363 return syms.errType;
3364 }
3365 }
3366 switch (boundkind) {
3367 case 0:
3368 return syms.botType;
3370 case ARRAY_BOUND:
3371 // calculate lub(A[], B[])
3372 List<Type> elements = Type.map(ts, elemTypeFun);
3373 for (Type t : elements) {
3374 if (t.isPrimitive()) {
3375 // if a primitive type is found, then return
3376 // arraySuperType unless all the types are the
3377 // same
3378 Type first = ts.head;
3379 for (Type s : ts.tail) {
3380 if (!isSameType(first, s)) {
3381 // lub(int[], B[]) is Cloneable & Serializable
3382 return arraySuperType();
3383 }
3384 }
3385 // all the array types are the same, return one
3386 // lub(int[], int[]) is int[]
3387 return first;
3388 }
3389 }
3390 // lub(A[], B[]) is lub(A, B)[]
3391 return new ArrayType(lub(elements), syms.arrayClass);
3393 case CLASS_BOUND:
3394 // calculate lub(A, B)
3395 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
3396 ts = ts.tail;
3397 Assert.check(!ts.isEmpty());
3398 //step 1 - compute erased candidate set (EC)
3399 List<Type> cl = erasedSupertypes(ts.head);
3400 for (Type t : ts.tail) {
3401 if (t.tag == CLASS || t.tag == TYPEVAR)
3402 cl = intersect(cl, erasedSupertypes(t));
3403 }
3404 //step 2 - compute minimal erased candidate set (MEC)
3405 List<Type> mec = closureMin(cl);
3406 //step 3 - for each element G in MEC, compute lci(Inv(G))
3407 List<Type> candidates = List.nil();
3408 for (Type erasedSupertype : mec) {
3409 List<Type> lci = List.of(asSuper(ts.head, erasedSupertype.tsym));
3410 for (Type t : ts) {
3411 lci = intersect(lci, List.of(asSuper(t, erasedSupertype.tsym)));
3412 }
3413 candidates = candidates.appendList(lci);
3414 }
3415 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
3416 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
3417 return compoundMin(candidates);
3419 default:
3420 // calculate lub(A, B[])
3421 List<Type> classes = List.of(arraySuperType());
3422 for (Type t : ts) {
3423 if (t.tag != ARRAY) // Filter out any arrays
3424 classes = classes.prepend(t);
3425 }
3426 // lub(A, B[]) is lub(A, arraySuperType)
3427 return lub(classes);
3428 }
3429 }
3430 // where
3431 List<Type> erasedSupertypes(Type t) {
3432 ListBuffer<Type> buf = lb();
3433 for (Type sup : closure(t)) {
3434 if (sup.tag == TYPEVAR) {
3435 buf.append(sup);
3436 } else {
3437 buf.append(erasure(sup));
3438 }
3439 }
3440 return buf.toList();
3441 }
3443 private Type arraySuperType = null;
3444 private Type arraySuperType() {
3445 // initialized lazily to avoid problems during compiler startup
3446 if (arraySuperType == null) {
3447 synchronized (this) {
3448 if (arraySuperType == null) {
3449 // JLS 10.8: all arrays implement Cloneable and Serializable.
3450 arraySuperType = makeCompoundType(List.of(syms.serializableType,
3451 syms.cloneableType), true);
3452 }
3453 }
3454 }
3455 return arraySuperType;
3456 }
3457 // </editor-fold>
3459 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
3460 public Type glb(List<Type> ts) {
3461 Type t1 = ts.head;
3462 for (Type t2 : ts.tail) {
3463 if (t1.isErroneous())
3464 return t1;
3465 t1 = glb(t1, t2);
3466 }
3467 return t1;
3468 }
3469 //where
3470 public Type glb(Type t, Type s) {
3471 if (s == null)
3472 return t;
3473 else if (t.isPrimitive() || s.isPrimitive())
3474 return syms.errType;
3475 else if (isSubtypeNoCapture(t, s))
3476 return t;
3477 else if (isSubtypeNoCapture(s, t))
3478 return s;
3480 List<Type> closure = union(closure(t), closure(s));
3481 List<Type> bounds = closureMin(closure);
3483 if (bounds.isEmpty()) { // length == 0
3484 return syms.objectType;
3485 } else if (bounds.tail.isEmpty()) { // length == 1
3486 return bounds.head;
3487 } else { // length > 1
3488 int classCount = 0;
3489 for (Type bound : bounds)
3490 if (!bound.isInterface())
3491 classCount++;
3492 if (classCount > 1)
3493 return createErrorType(t);
3494 }
3495 return makeCompoundType(bounds);
3496 }
3497 // </editor-fold>
3499 // <editor-fold defaultstate="collapsed" desc="hashCode">
3500 /**
3501 * Compute a hash code on a type.
3502 */
3503 public int hashCode(Type t) {
3504 return hashCode.visit(t);
3505 }
3506 // where
3507 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
3509 public Integer visitType(Type t, Void ignored) {
3510 return t.tag.ordinal();
3511 }
3513 @Override
3514 public Integer visitClassType(ClassType t, Void ignored) {
3515 int result = visit(t.getEnclosingType());
3516 result *= 127;
3517 result += t.tsym.flatName().hashCode();
3518 for (Type s : t.getTypeArguments()) {
3519 result *= 127;
3520 result += visit(s);
3521 }
3522 return result;
3523 }
3525 @Override
3526 public Integer visitMethodType(MethodType t, Void ignored) {
3527 int h = METHOD.ordinal();
3528 for (List<Type> thisargs = t.argtypes;
3529 thisargs.tail != null;
3530 thisargs = thisargs.tail)
3531 h = (h << 5) + visit(thisargs.head);
3532 return (h << 5) + visit(t.restype);
3533 }
3535 @Override
3536 public Integer visitWildcardType(WildcardType t, Void ignored) {
3537 int result = t.kind.hashCode();
3538 if (t.type != null) {
3539 result *= 127;
3540 result += visit(t.type);
3541 }
3542 return result;
3543 }
3545 @Override
3546 public Integer visitArrayType(ArrayType t, Void ignored) {
3547 return visit(t.elemtype) + 12;
3548 }
3550 @Override
3551 public Integer visitTypeVar(TypeVar t, Void ignored) {
3552 return System.identityHashCode(t.tsym);
3553 }
3555 @Override
3556 public Integer visitUndetVar(UndetVar t, Void ignored) {
3557 return System.identityHashCode(t);
3558 }
3560 @Override
3561 public Integer visitErrorType(ErrorType t, Void ignored) {
3562 return 0;
3563 }
3564 };
3565 // </editor-fold>
3567 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
3568 /**
3569 * Does t have a result that is a subtype of the result type of s,
3570 * suitable for covariant returns? It is assumed that both types
3571 * are (possibly polymorphic) method types. Monomorphic method
3572 * types are handled in the obvious way. Polymorphic method types
3573 * require renaming all type variables of one to corresponding
3574 * type variables in the other, where correspondence is by
3575 * position in the type parameter list. */
3576 public boolean resultSubtype(Type t, Type s, Warner warner) {
3577 List<Type> tvars = t.getTypeArguments();
3578 List<Type> svars = s.getTypeArguments();
3579 Type tres = t.getReturnType();
3580 Type sres = subst(s.getReturnType(), svars, tvars);
3581 return covariantReturnType(tres, sres, warner);
3582 }
3584 /**
3585 * Return-Type-Substitutable.
3586 * @jls section 8.4.5
3587 */
3588 public boolean returnTypeSubstitutable(Type r1, Type r2) {
3589 if (hasSameArgs(r1, r2))
3590 return resultSubtype(r1, r2, noWarnings);
3591 else
3592 return covariantReturnType(r1.getReturnType(),
3593 erasure(r2.getReturnType()),
3594 noWarnings);
3595 }
3597 public boolean returnTypeSubstitutable(Type r1,
3598 Type r2, Type r2res,
3599 Warner warner) {
3600 if (isSameType(r1.getReturnType(), r2res))
3601 return true;
3602 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
3603 return false;
3605 if (hasSameArgs(r1, r2))
3606 return covariantReturnType(r1.getReturnType(), r2res, warner);
3607 if (!allowCovariantReturns)
3608 return false;
3609 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
3610 return true;
3611 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
3612 return false;
3613 warner.warn(LintCategory.UNCHECKED);
3614 return true;
3615 }
3617 /**
3618 * Is t an appropriate return type in an overrider for a
3619 * method that returns s?
3620 */
3621 public boolean covariantReturnType(Type t, Type s, Warner warner) {
3622 return
3623 isSameType(t, s) ||
3624 allowCovariantReturns &&
3625 !t.isPrimitive() &&
3626 !s.isPrimitive() &&
3627 isAssignable(t, s, warner);
3628 }
3629 // </editor-fold>
3631 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
3632 /**
3633 * Return the class that boxes the given primitive.
3634 */
3635 public ClassSymbol boxedClass(Type t) {
3636 return reader.enterClass(syms.boxedName[t.tag.ordinal()]);
3637 }
3639 /**
3640 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
3641 */
3642 public Type boxedTypeOrType(Type t) {
3643 return t.isPrimitive() ?
3644 boxedClass(t).type :
3645 t;
3646 }
3648 /**
3649 * Return the primitive type corresponding to a boxed type.
3650 */
3651 public Type unboxedType(Type t) {
3652 if (allowBoxing) {
3653 for (int i=0; i<syms.boxedName.length; i++) {
3654 Name box = syms.boxedName[i];
3655 if (box != null &&
3656 asSuper(t, reader.enterClass(box)) != null)
3657 return syms.typeOfTag[i];
3658 }
3659 }
3660 return Type.noType;
3661 }
3663 /**
3664 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
3665 */
3666 public Type unboxedTypeOrType(Type t) {
3667 Type unboxedType = unboxedType(t);
3668 return unboxedType.tag == NONE ? t : unboxedType;
3669 }
3670 // </editor-fold>
3672 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3673 /*
3674 * JLS 5.1.10 Capture Conversion:
3675 *
3676 * Let G name a generic type declaration with n formal type
3677 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3678 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3679 * where, for 1 <= i <= n:
3680 *
3681 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3682 * Si is a fresh type variable whose upper bound is
3683 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3684 * type.
3685 *
3686 * + If Ti is a wildcard type argument of the form ? extends Bi,
3687 * then Si is a fresh type variable whose upper bound is
3688 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3689 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3690 * a compile-time error if for any two classes (not interfaces)
3691 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3692 *
3693 * + If Ti is a wildcard type argument of the form ? super Bi,
3694 * then Si is a fresh type variable whose upper bound is
3695 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3696 *
3697 * + Otherwise, Si = Ti.
3698 *
3699 * Capture conversion on any type other than a parameterized type
3700 * (4.5) acts as an identity conversion (5.1.1). Capture
3701 * conversions never require a special action at run time and
3702 * therefore never throw an exception at run time.
3703 *
3704 * Capture conversion is not applied recursively.
3705 */
3706 /**
3707 * Capture conversion as specified by the JLS.
3708 */
3710 public List<Type> capture(List<Type> ts) {
3711 List<Type> buf = List.nil();
3712 for (Type t : ts) {
3713 buf = buf.prepend(capture(t));
3714 }
3715 return buf.reverse();
3716 }
3717 public Type capture(Type t) {
3718 if (t.tag != CLASS)
3719 return t;
3720 if (t.getEnclosingType() != Type.noType) {
3721 Type capturedEncl = capture(t.getEnclosingType());
3722 if (capturedEncl != t.getEnclosingType()) {
3723 Type type1 = memberType(capturedEncl, t.tsym);
3724 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3725 }
3726 }
3727 t = t.unannotatedType();
3728 ClassType cls = (ClassType)t;
3729 if (cls.isRaw() || !cls.isParameterized())
3730 return cls;
3732 ClassType G = (ClassType)cls.asElement().asType();
3733 List<Type> A = G.getTypeArguments();
3734 List<Type> T = cls.getTypeArguments();
3735 List<Type> S = freshTypeVariables(T);
3737 List<Type> currentA = A;
3738 List<Type> currentT = T;
3739 List<Type> currentS = S;
3740 boolean captured = false;
3741 while (!currentA.isEmpty() &&
3742 !currentT.isEmpty() &&
3743 !currentS.isEmpty()) {
3744 if (currentS.head != currentT.head) {
3745 captured = true;
3746 WildcardType Ti = (WildcardType)currentT.head;
3747 Type Ui = currentA.head.getUpperBound();
3748 CapturedType Si = (CapturedType)currentS.head;
3749 if (Ui == null)
3750 Ui = syms.objectType;
3751 switch (Ti.kind) {
3752 case UNBOUND:
3753 Si.bound = subst(Ui, A, S);
3754 Si.lower = syms.botType;
3755 break;
3756 case EXTENDS:
3757 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3758 Si.lower = syms.botType;
3759 break;
3760 case SUPER:
3761 Si.bound = subst(Ui, A, S);
3762 Si.lower = Ti.getSuperBound();
3763 break;
3764 }
3765 if (Si.bound == Si.lower)
3766 currentS.head = Si.bound;
3767 }
3768 currentA = currentA.tail;
3769 currentT = currentT.tail;
3770 currentS = currentS.tail;
3771 }
3772 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3773 return erasure(t); // some "rare" type involved
3775 if (captured)
3776 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3777 else
3778 return t;
3779 }
3780 // where
3781 public List<Type> freshTypeVariables(List<Type> types) {
3782 ListBuffer<Type> result = lb();
3783 for (Type t : types) {
3784 if (t.tag == WILDCARD) {
3785 Type bound = ((WildcardType)t).getExtendsBound();
3786 if (bound == null)
3787 bound = syms.objectType;
3788 result.append(new CapturedType(capturedName,
3789 syms.noSymbol,
3790 bound,
3791 syms.botType,
3792 (WildcardType)t));
3793 } else {
3794 result.append(t);
3795 }
3796 }
3797 return result.toList();
3798 }
3799 // </editor-fold>
3801 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3802 private List<Type> upperBounds(List<Type> ss) {
3803 if (ss.isEmpty()) return ss;
3804 Type head = upperBound(ss.head);
3805 List<Type> tail = upperBounds(ss.tail);
3806 if (head != ss.head || tail != ss.tail)
3807 return tail.prepend(head);
3808 else
3809 return ss;
3810 }
3812 private boolean sideCast(Type from, Type to, Warner warn) {
3813 // We are casting from type $from$ to type $to$, which are
3814 // non-final unrelated types. This method
3815 // tries to reject a cast by transferring type parameters
3816 // from $to$ to $from$ by common superinterfaces.
3817 boolean reverse = false;
3818 Type target = to;
3819 if ((to.tsym.flags() & INTERFACE) == 0) {
3820 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3821 reverse = true;
3822 to = from;
3823 from = target;
3824 }
3825 List<Type> commonSupers = superClosure(to, erasure(from));
3826 boolean giveWarning = commonSupers.isEmpty();
3827 // The arguments to the supers could be unified here to
3828 // get a more accurate analysis
3829 while (commonSupers.nonEmpty()) {
3830 Type t1 = asSuper(from, commonSupers.head.tsym);
3831 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3832 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3833 return false;
3834 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3835 commonSupers = commonSupers.tail;
3836 }
3837 if (giveWarning && !isReifiable(reverse ? from : to))
3838 warn.warn(LintCategory.UNCHECKED);
3839 if (!allowCovariantReturns)
3840 // reject if there is a common method signature with
3841 // incompatible return types.
3842 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3843 return true;
3844 }
3846 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3847 // We are casting from type $from$ to type $to$, which are
3848 // unrelated types one of which is final and the other of
3849 // which is an interface. This method
3850 // tries to reject a cast by transferring type parameters
3851 // from the final class to the interface.
3852 boolean reverse = false;
3853 Type target = to;
3854 if ((to.tsym.flags() & INTERFACE) == 0) {
3855 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3856 reverse = true;
3857 to = from;
3858 from = target;
3859 }
3860 Assert.check((from.tsym.flags() & FINAL) != 0);
3861 Type t1 = asSuper(from, to.tsym);
3862 if (t1 == null) return false;
3863 Type t2 = to;
3864 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3865 return false;
3866 if (!allowCovariantReturns)
3867 // reject if there is a common method signature with
3868 // incompatible return types.
3869 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3870 if (!isReifiable(target) &&
3871 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3872 warn.warn(LintCategory.UNCHECKED);
3873 return true;
3874 }
3876 private boolean giveWarning(Type from, Type to) {
3877 Type subFrom = asSub(from, to.tsym);
3878 return to.isParameterized() &&
3879 (!(isUnbounded(to) ||
3880 isSubtype(from, to) ||
3881 ((subFrom != null) && containsType(to.allparams(), subFrom.allparams()))));
3882 }
3884 private List<Type> superClosure(Type t, Type s) {
3885 List<Type> cl = List.nil();
3886 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3887 if (isSubtype(s, erasure(l.head))) {
3888 cl = insert(cl, l.head);
3889 } else {
3890 cl = union(cl, superClosure(l.head, s));
3891 }
3892 }
3893 return cl;
3894 }
3896 private boolean containsTypeEquivalent(Type t, Type s) {
3897 return
3898 isSameType(t, s) || // shortcut
3899 containsType(t, s) && containsType(s, t);
3900 }
3902 // <editor-fold defaultstate="collapsed" desc="adapt">
3903 /**
3904 * Adapt a type by computing a substitution which maps a source
3905 * type to a target type.
3906 *
3907 * @param source the source type
3908 * @param target the target type
3909 * @param from the type variables of the computed substitution
3910 * @param to the types of the computed substitution.
3911 */
3912 public void adapt(Type source,
3913 Type target,
3914 ListBuffer<Type> from,
3915 ListBuffer<Type> to) throws AdaptFailure {
3916 new Adapter(from, to).adapt(source, target);
3917 }
3919 class Adapter extends SimpleVisitor<Void, Type> {
3921 ListBuffer<Type> from;
3922 ListBuffer<Type> to;
3923 Map<Symbol,Type> mapping;
3925 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3926 this.from = from;
3927 this.to = to;
3928 mapping = new HashMap<Symbol,Type>();
3929 }
3931 public void adapt(Type source, Type target) throws AdaptFailure {
3932 visit(source, target);
3933 List<Type> fromList = from.toList();
3934 List<Type> toList = to.toList();
3935 while (!fromList.isEmpty()) {
3936 Type val = mapping.get(fromList.head.tsym);
3937 if (toList.head != val)
3938 toList.head = val;
3939 fromList = fromList.tail;
3940 toList = toList.tail;
3941 }
3942 }
3944 @Override
3945 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3946 if (target.tag == CLASS)
3947 adaptRecursive(source.allparams(), target.allparams());
3948 return null;
3949 }
3951 @Override
3952 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3953 if (target.tag == ARRAY)
3954 adaptRecursive(elemtype(source), elemtype(target));
3955 return null;
3956 }
3958 @Override
3959 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3960 if (source.isExtendsBound())
3961 adaptRecursive(upperBound(source), upperBound(target));
3962 else if (source.isSuperBound())
3963 adaptRecursive(lowerBound(source), lowerBound(target));
3964 return null;
3965 }
3967 @Override
3968 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3969 // Check to see if there is
3970 // already a mapping for $source$, in which case
3971 // the old mapping will be merged with the new
3972 Type val = mapping.get(source.tsym);
3973 if (val != null) {
3974 if (val.isSuperBound() && target.isSuperBound()) {
3975 val = isSubtype(lowerBound(val), lowerBound(target))
3976 ? target : val;
3977 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3978 val = isSubtype(upperBound(val), upperBound(target))
3979 ? val : target;
3980 } else if (!isSameType(val, target)) {
3981 throw new AdaptFailure();
3982 }
3983 } else {
3984 val = target;
3985 from.append(source);
3986 to.append(target);
3987 }
3988 mapping.put(source.tsym, val);
3989 return null;
3990 }
3992 @Override
3993 public Void visitType(Type source, Type target) {
3994 return null;
3995 }
3997 private Set<TypePair> cache = new HashSet<TypePair>();
3999 private void adaptRecursive(Type source, Type target) {
4000 TypePair pair = new TypePair(source, target);
4001 if (cache.add(pair)) {
4002 try {
4003 visit(source, target);
4004 } finally {
4005 cache.remove(pair);
4006 }
4007 }
4008 }
4010 private void adaptRecursive(List<Type> source, List<Type> target) {
4011 if (source.length() == target.length()) {
4012 while (source.nonEmpty()) {
4013 adaptRecursive(source.head, target.head);
4014 source = source.tail;
4015 target = target.tail;
4016 }
4017 }
4018 }
4019 }
4021 public static class AdaptFailure extends RuntimeException {
4022 static final long serialVersionUID = -7490231548272701566L;
4023 }
4025 private void adaptSelf(Type t,
4026 ListBuffer<Type> from,
4027 ListBuffer<Type> to) {
4028 try {
4029 //if (t.tsym.type != t)
4030 adapt(t.tsym.type, t, from, to);
4031 } catch (AdaptFailure ex) {
4032 // Adapt should never fail calculating a mapping from
4033 // t.tsym.type to t as there can be no merge problem.
4034 throw new AssertionError(ex);
4035 }
4036 }
4037 // </editor-fold>
4039 /**
4040 * Rewrite all type variables (universal quantifiers) in the given
4041 * type to wildcards (existential quantifiers). This is used to
4042 * determine if a cast is allowed. For example, if high is true
4043 * and {@code T <: Number}, then {@code List<T>} is rewritten to
4044 * {@code List<? extends Number>}. Since {@code List<Integer> <:
4045 * List<? extends Number>} a {@code List<T>} can be cast to {@code
4046 * List<Integer>} with a warning.
4047 * @param t a type
4048 * @param high if true return an upper bound; otherwise a lower
4049 * bound
4050 * @param rewriteTypeVars only rewrite captured wildcards if false;
4051 * otherwise rewrite all type variables
4052 * @return the type rewritten with wildcards (existential
4053 * quantifiers) only
4054 */
4055 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
4056 return new Rewriter(high, rewriteTypeVars).visit(t);
4057 }
4059 class Rewriter extends UnaryVisitor<Type> {
4061 boolean high;
4062 boolean rewriteTypeVars;
4064 Rewriter(boolean high, boolean rewriteTypeVars) {
4065 this.high = high;
4066 this.rewriteTypeVars = rewriteTypeVars;
4067 }
4069 @Override
4070 public Type visitClassType(ClassType t, Void s) {
4071 ListBuffer<Type> rewritten = new ListBuffer<Type>();
4072 boolean changed = false;
4073 for (Type arg : t.allparams()) {
4074 Type bound = visit(arg);
4075 if (arg != bound) {
4076 changed = true;
4077 }
4078 rewritten.append(bound);
4079 }
4080 if (changed)
4081 return subst(t.tsym.type,
4082 t.tsym.type.allparams(),
4083 rewritten.toList());
4084 else
4085 return t;
4086 }
4088 public Type visitType(Type t, Void s) {
4089 return high ? upperBound(t) : lowerBound(t);
4090 }
4092 @Override
4093 public Type visitCapturedType(CapturedType t, Void s) {
4094 Type w_bound = t.wildcard.type;
4095 Type bound = w_bound.contains(t) ?
4096 erasure(w_bound) :
4097 visit(w_bound);
4098 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
4099 }
4101 @Override
4102 public Type visitTypeVar(TypeVar t, Void s) {
4103 if (rewriteTypeVars) {
4104 Type bound = t.bound.contains(t) ?
4105 erasure(t.bound) :
4106 visit(t.bound);
4107 return rewriteAsWildcardType(bound, t, EXTENDS);
4108 } else {
4109 return t;
4110 }
4111 }
4113 @Override
4114 public Type visitWildcardType(WildcardType t, Void s) {
4115 Type bound2 = visit(t.type);
4116 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
4117 }
4119 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
4120 switch (bk) {
4121 case EXTENDS: return high ?
4122 makeExtendsWildcard(B(bound), formal) :
4123 makeExtendsWildcard(syms.objectType, formal);
4124 case SUPER: return high ?
4125 makeSuperWildcard(syms.botType, formal) :
4126 makeSuperWildcard(B(bound), formal);
4127 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
4128 default:
4129 Assert.error("Invalid bound kind " + bk);
4130 return null;
4131 }
4132 }
4134 Type B(Type t) {
4135 while (t.tag == WILDCARD) {
4136 WildcardType w = (WildcardType)t;
4137 t = high ?
4138 w.getExtendsBound() :
4139 w.getSuperBound();
4140 if (t == null) {
4141 t = high ? syms.objectType : syms.botType;
4142 }
4143 }
4144 return t;
4145 }
4146 }
4149 /**
4150 * Create a wildcard with the given upper (extends) bound; create
4151 * an unbounded wildcard if bound is Object.
4152 *
4153 * @param bound the upper bound
4154 * @param formal the formal type parameter that will be
4155 * substituted by the wildcard
4156 */
4157 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4158 if (bound == syms.objectType) {
4159 return new WildcardType(syms.objectType,
4160 BoundKind.UNBOUND,
4161 syms.boundClass,
4162 formal);
4163 } else {
4164 return new WildcardType(bound,
4165 BoundKind.EXTENDS,
4166 syms.boundClass,
4167 formal);
4168 }
4169 }
4171 /**
4172 * Create a wildcard with the given lower (super) bound; create an
4173 * unbounded wildcard if bound is bottom (type of {@code null}).
4174 *
4175 * @param bound the lower bound
4176 * @param formal the formal type parameter that will be
4177 * substituted by the wildcard
4178 */
4179 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4180 if (bound.tag == BOT) {
4181 return new WildcardType(syms.objectType,
4182 BoundKind.UNBOUND,
4183 syms.boundClass,
4184 formal);
4185 } else {
4186 return new WildcardType(bound,
4187 BoundKind.SUPER,
4188 syms.boundClass,
4189 formal);
4190 }
4191 }
4193 /**
4194 * A wrapper for a type that allows use in sets.
4195 */
4196 public static class UniqueType {
4197 public final Type type;
4198 final Types types;
4200 public UniqueType(Type type, Types types) {
4201 this.type = type;
4202 this.types = types;
4203 }
4205 public int hashCode() {
4206 return types.hashCode(type);
4207 }
4209 public boolean equals(Object obj) {
4210 return (obj instanceof UniqueType) &&
4211 types.isSameType(type, ((UniqueType)obj).type);
4212 }
4214 public String toString() {
4215 return type.toString();
4216 }
4218 }
4219 // </editor-fold>
4221 // <editor-fold defaultstate="collapsed" desc="Visitors">
4222 /**
4223 * A default visitor for types. All visitor methods except
4224 * visitType are implemented by delegating to visitType. Concrete
4225 * subclasses must provide an implementation of visitType and can
4226 * override other methods as needed.
4227 *
4228 * @param <R> the return type of the operation implemented by this
4229 * visitor; use Void if no return type is needed.
4230 * @param <S> the type of the second argument (the first being the
4231 * type itself) of the operation implemented by this visitor; use
4232 * Void if a second argument is not needed.
4233 */
4234 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4235 final public R visit(Type t, S s) { return t.accept(this, s); }
4236 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4237 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4238 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4239 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4240 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4241 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4242 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4243 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4244 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4245 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4246 // Pretend annotations don't exist
4247 public R visitAnnotatedType(AnnotatedType t, S s) { return visit(t.underlyingType, s); }
4248 }
4250 /**
4251 * A default visitor for symbols. All visitor methods except
4252 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4253 * subclasses must provide an implementation of visitSymbol and can
4254 * override other methods as needed.
4255 *
4256 * @param <R> the return type of the operation implemented by this
4257 * visitor; use Void if no return type is needed.
4258 * @param <S> the type of the second argument (the first being the
4259 * symbol itself) of the operation implemented by this visitor; use
4260 * Void if a second argument is not needed.
4261 */
4262 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4263 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
4264 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4265 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4266 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4267 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4268 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4269 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4270 }
4272 /**
4273 * A <em>simple</em> visitor for types. This visitor is simple as
4274 * captured wildcards, for-all types (generic methods), and
4275 * undetermined type variables (part of inference) are hidden.
4276 * Captured wildcards are hidden by treating them as type
4277 * variables and the rest are hidden by visiting their qtypes.
4278 *
4279 * @param <R> the return type of the operation implemented by this
4280 * visitor; use Void if no return type is needed.
4281 * @param <S> the type of the second argument (the first being the
4282 * type itself) of the operation implemented by this visitor; use
4283 * Void if a second argument is not needed.
4284 */
4285 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4286 @Override
4287 public R visitCapturedType(CapturedType t, S s) {
4288 return visitTypeVar(t, s);
4289 }
4290 @Override
4291 public R visitForAll(ForAll t, S s) {
4292 return visit(t.qtype, s);
4293 }
4294 @Override
4295 public R visitUndetVar(UndetVar t, S s) {
4296 return visit(t.qtype, s);
4297 }
4298 }
4300 /**
4301 * A plain relation on types. That is a 2-ary function on the
4302 * form Type × Type → Boolean.
4303 * <!-- In plain text: Type x Type -> Boolean -->
4304 */
4305 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4307 /**
4308 * A convenience visitor for implementing operations that only
4309 * require one argument (the type itself), that is, unary
4310 * operations.
4311 *
4312 * @param <R> the return type of the operation implemented by this
4313 * visitor; use Void if no return type is needed.
4314 */
4315 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4316 final public R visit(Type t) { return t.accept(this, null); }
4317 }
4319 /**
4320 * A visitor for implementing a mapping from types to types. The
4321 * default behavior of this class is to implement the identity
4322 * mapping (mapping a type to itself). This can be overridden in
4323 * subclasses.
4324 *
4325 * @param <S> the type of the second argument (the first being the
4326 * type itself) of this mapping; use Void if a second argument is
4327 * not needed.
4328 */
4329 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4330 final public Type visit(Type t) { return t.accept(this, null); }
4331 public Type visitType(Type t, S s) { return t; }
4332 }
4333 // </editor-fold>
4336 // <editor-fold defaultstate="collapsed" desc="Annotation support">
4338 public RetentionPolicy getRetention(Attribute.Compound a) {
4339 return getRetention(a.type.tsym);
4340 }
4342 public RetentionPolicy getRetention(Symbol sym) {
4343 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
4344 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
4345 if (c != null) {
4346 Attribute value = c.member(names.value);
4347 if (value != null && value instanceof Attribute.Enum) {
4348 Name levelName = ((Attribute.Enum)value).value.name;
4349 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
4350 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
4351 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
4352 else ;// /* fail soft */ throw new AssertionError(levelName);
4353 }
4354 }
4355 return vis;
4356 }
4357 // </editor-fold>
4359 // <editor-fold defaultstate="collapsed" desc="Signature Generation">
4361 public static abstract class SignatureGenerator {
4363 private final Types types;
4365 protected abstract void append(char ch);
4366 protected abstract void append(byte[] ba);
4367 protected abstract void append(Name name);
4368 protected void classReference(ClassSymbol c) { /* by default: no-op */ }
4370 protected SignatureGenerator(Types types) {
4371 this.types = types;
4372 }
4374 /**
4375 * Assemble signature of given type in string buffer.
4376 */
4377 public void assembleSig(Type type) {
4378 type = type.unannotatedType();
4379 switch (type.getTag()) {
4380 case BYTE:
4381 append('B');
4382 break;
4383 case SHORT:
4384 append('S');
4385 break;
4386 case CHAR:
4387 append('C');
4388 break;
4389 case INT:
4390 append('I');
4391 break;
4392 case LONG:
4393 append('J');
4394 break;
4395 case FLOAT:
4396 append('F');
4397 break;
4398 case DOUBLE:
4399 append('D');
4400 break;
4401 case BOOLEAN:
4402 append('Z');
4403 break;
4404 case VOID:
4405 append('V');
4406 break;
4407 case CLASS:
4408 append('L');
4409 assembleClassSig(type);
4410 append(';');
4411 break;
4412 case ARRAY:
4413 ArrayType at = (ArrayType) type;
4414 append('[');
4415 assembleSig(at.elemtype);
4416 break;
4417 case METHOD:
4418 MethodType mt = (MethodType) type;
4419 append('(');
4420 assembleSig(mt.argtypes);
4421 append(')');
4422 assembleSig(mt.restype);
4423 if (hasTypeVar(mt.thrown)) {
4424 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
4425 append('^');
4426 assembleSig(l.head);
4427 }
4428 }
4429 break;
4430 case WILDCARD: {
4431 Type.WildcardType ta = (Type.WildcardType) type;
4432 switch (ta.kind) {
4433 case SUPER:
4434 append('-');
4435 assembleSig(ta.type);
4436 break;
4437 case EXTENDS:
4438 append('+');
4439 assembleSig(ta.type);
4440 break;
4441 case UNBOUND:
4442 append('*');
4443 break;
4444 default:
4445 throw new AssertionError(ta.kind);
4446 }
4447 break;
4448 }
4449 case TYPEVAR:
4450 append('T');
4451 append(type.tsym.name);
4452 append(';');
4453 break;
4454 case FORALL:
4455 Type.ForAll ft = (Type.ForAll) type;
4456 assembleParamsSig(ft.tvars);
4457 assembleSig(ft.qtype);
4458 break;
4459 default:
4460 throw new AssertionError("typeSig " + type.getTag());
4461 }
4462 }
4464 public boolean hasTypeVar(List<Type> l) {
4465 while (l.nonEmpty()) {
4466 if (l.head.hasTag(TypeTag.TYPEVAR)) {
4467 return true;
4468 }
4469 l = l.tail;
4470 }
4471 return false;
4472 }
4474 public void assembleClassSig(Type type) {
4475 type = type.unannotatedType();
4476 ClassType ct = (ClassType) type;
4477 ClassSymbol c = (ClassSymbol) ct.tsym;
4478 classReference(c);
4479 Type outer = ct.getEnclosingType();
4480 if (outer.allparams().nonEmpty()) {
4481 boolean rawOuter =
4482 c.owner.kind == Kinds.MTH || // either a local class
4483 c.name == types.names.empty; // or anonymous
4484 assembleClassSig(rawOuter
4485 ? types.erasure(outer)
4486 : outer);
4487 append('.');
4488 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
4489 append(rawOuter
4490 ? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength())
4491 : c.name);
4492 } else {
4493 append(externalize(c.flatname));
4494 }
4495 if (ct.getTypeArguments().nonEmpty()) {
4496 append('<');
4497 assembleSig(ct.getTypeArguments());
4498 append('>');
4499 }
4500 }
4502 public void assembleParamsSig(List<Type> typarams) {
4503 append('<');
4504 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
4505 Type.TypeVar tvar = (Type.TypeVar) ts.head;
4506 append(tvar.tsym.name);
4507 List<Type> bounds = types.getBounds(tvar);
4508 if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
4509 append(':');
4510 }
4511 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
4512 append(':');
4513 assembleSig(l.head);
4514 }
4515 }
4516 append('>');
4517 }
4519 private void assembleSig(List<Type> types) {
4520 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
4521 assembleSig(ts.head);
4522 }
4523 }
4524 }
4525 // </editor-fold>
4526 }
