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src/share/classes/com/sun/tools/javac/code/Types.java@4d68e2a05b50
src/share/classes/com/sun/tools/javac/code/Types.java
Tue, 27 Nov 2012 13:55:10 -0800
- author
- jjg
- date
- Tue, 27 Nov 2012 13:55:10 -0800
- changeset 1430
- 4d68e2a05b50
- parent 1415
- 01c9d4161882
- child 1434
- 34d1ebaf4645
- permissions
- -rw-r--r--
8004068: Fix build problems caused by on-demand imports
Reviewed-by: jjg
Contributed-by: eric.caspole@amd.com
1 /*
2 * Copyright (c) 2003, 2012, 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 com.sun.tools.javac.code.Attribute.RetentionPolicy;
38 import com.sun.tools.javac.code.Lint.LintCategory;
39 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
40 import com.sun.tools.javac.comp.Check;
41 import com.sun.tools.javac.jvm.ClassReader;
42 import com.sun.tools.javac.util.*;
43 import com.sun.tools.javac.util.List;
44 import static com.sun.tools.javac.code.BoundKind.*;
45 import static com.sun.tools.javac.code.Flags.*;
46 import static com.sun.tools.javac.code.Scope.*;
47 import static com.sun.tools.javac.code.Symbol.*;
48 import static com.sun.tools.javac.code.Type.*;
49 import static com.sun.tools.javac.code.TypeTag.*;
50 import static com.sun.tools.javac.util.ListBuffer.lb;
52 /**
53 * Utility class containing various operations on types.
54 *
55 * <p>Unless other names are more illustrative, the following naming
56 * conventions should be observed in this file:
57 *
58 * <dl>
59 * <dt>t</dt>
60 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
61 * <dt>s</dt>
62 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
63 * <dt>ts</dt>
64 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
65 * <dt>ss</dt>
66 * <dd>A second list of types should be named ss.</dd>
67 * </dl>
68 *
69 * <p><b>This is NOT part of any supported API.
70 * If you write code that depends on this, you do so at your own risk.
71 * This code and its internal interfaces are subject to change or
72 * deletion without notice.</b>
73 */
74 public class Types {
75 protected static final Context.Key<Types> typesKey =
76 new Context.Key<Types>();
78 final Symtab syms;
79 final JavacMessages messages;
80 final Names names;
81 final boolean allowBoxing;
82 final boolean allowCovariantReturns;
83 final boolean allowObjectToPrimitiveCast;
84 final boolean allowDefaultMethods;
85 final ClassReader reader;
86 final Check chk;
87 JCDiagnostic.Factory diags;
88 List<Warner> warnStack = List.nil();
89 final Name capturedName;
90 private final FunctionDescriptorLookupError functionDescriptorLookupError;
92 public final Warner noWarnings;
94 // <editor-fold defaultstate="collapsed" desc="Instantiating">
95 public static Types instance(Context context) {
96 Types instance = context.get(typesKey);
97 if (instance == null)
98 instance = new Types(context);
99 return instance;
100 }
102 protected Types(Context context) {
103 context.put(typesKey, this);
104 syms = Symtab.instance(context);
105 names = Names.instance(context);
106 Source source = Source.instance(context);
107 allowBoxing = source.allowBoxing();
108 allowCovariantReturns = source.allowCovariantReturns();
109 allowObjectToPrimitiveCast = source.allowObjectToPrimitiveCast();
110 allowDefaultMethods = source.allowDefaultMethods();
111 reader = ClassReader.instance(context);
112 chk = Check.instance(context);
113 capturedName = names.fromString("<captured wildcard>");
114 messages = JavacMessages.instance(context);
115 diags = JCDiagnostic.Factory.instance(context);
116 functionDescriptorLookupError = new FunctionDescriptorLookupError();
117 noWarnings = new Warner(null);
118 }
119 // </editor-fold>
121 // <editor-fold defaultstate="collapsed" desc="upperBound">
122 /**
123 * The "rvalue conversion".<br>
124 * The upper bound of most types is the type
125 * itself. Wildcards, on the other hand have upper
126 * and lower bounds.
127 * @param t a type
128 * @return the upper bound of the given type
129 */
130 public Type upperBound(Type t) {
131 return upperBound.visit(t);
132 }
133 // where
134 private final MapVisitor<Void> upperBound = new MapVisitor<Void>() {
136 @Override
137 public Type visitWildcardType(WildcardType t, Void ignored) {
138 if (t.isSuperBound())
139 return t.bound == null ? syms.objectType : t.bound.bound;
140 else
141 return visit(t.type);
142 }
144 @Override
145 public Type visitCapturedType(CapturedType t, Void ignored) {
146 return visit(t.bound);
147 }
148 };
149 // </editor-fold>
151 // <editor-fold defaultstate="collapsed" desc="lowerBound">
152 /**
153 * The "lvalue conversion".<br>
154 * The lower bound of most types is the type
155 * itself. Wildcards, on the other hand have upper
156 * and lower bounds.
157 * @param t a type
158 * @return the lower bound of the given type
159 */
160 public Type lowerBound(Type t) {
161 return lowerBound.visit(t);
162 }
163 // where
164 private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() {
166 @Override
167 public Type visitWildcardType(WildcardType t, Void ignored) {
168 return t.isExtendsBound() ? syms.botType : visit(t.type);
169 }
171 @Override
172 public Type visitCapturedType(CapturedType t, Void ignored) {
173 return visit(t.getLowerBound());
174 }
175 };
176 // </editor-fold>
178 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
179 /**
180 * Checks that all the arguments to a class are unbounded
181 * wildcards or something else that doesn't make any restrictions
182 * on the arguments. If a class isUnbounded, a raw super- or
183 * subclass can be cast to it without a warning.
184 * @param t a type
185 * @return true iff the given type is unbounded or raw
186 */
187 public boolean isUnbounded(Type t) {
188 return isUnbounded.visit(t);
189 }
190 // where
191 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
193 public Boolean visitType(Type t, Void ignored) {
194 return true;
195 }
197 @Override
198 public Boolean visitClassType(ClassType t, Void ignored) {
199 List<Type> parms = t.tsym.type.allparams();
200 List<Type> args = t.allparams();
201 while (parms.nonEmpty()) {
202 WildcardType unb = new WildcardType(syms.objectType,
203 BoundKind.UNBOUND,
204 syms.boundClass,
205 (TypeVar)parms.head);
206 if (!containsType(args.head, unb))
207 return false;
208 parms = parms.tail;
209 args = args.tail;
210 }
211 return true;
212 }
213 };
214 // </editor-fold>
216 // <editor-fold defaultstate="collapsed" desc="asSub">
217 /**
218 * Return the least specific subtype of t that starts with symbol
219 * sym. If none exists, return null. The least specific subtype
220 * is determined as follows:
221 *
222 * <p>If there is exactly one parameterized instance of sym that is a
223 * subtype of t, that parameterized instance is returned.<br>
224 * Otherwise, if the plain type or raw type `sym' is a subtype of
225 * type t, the type `sym' itself is returned. Otherwise, null is
226 * returned.
227 */
228 public Type asSub(Type t, Symbol sym) {
229 return asSub.visit(t, sym);
230 }
231 // where
232 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
234 public Type visitType(Type t, Symbol sym) {
235 return null;
236 }
238 @Override
239 public Type visitClassType(ClassType t, Symbol sym) {
240 if (t.tsym == sym)
241 return t;
242 Type base = asSuper(sym.type, t.tsym);
243 if (base == null)
244 return null;
245 ListBuffer<Type> from = new ListBuffer<Type>();
246 ListBuffer<Type> to = new ListBuffer<Type>();
247 try {
248 adapt(base, t, from, to);
249 } catch (AdaptFailure ex) {
250 return null;
251 }
252 Type res = subst(sym.type, from.toList(), to.toList());
253 if (!isSubtype(res, t))
254 return null;
255 ListBuffer<Type> openVars = new ListBuffer<Type>();
256 for (List<Type> l = sym.type.allparams();
257 l.nonEmpty(); l = l.tail)
258 if (res.contains(l.head) && !t.contains(l.head))
259 openVars.append(l.head);
260 if (openVars.nonEmpty()) {
261 if (t.isRaw()) {
262 // The subtype of a raw type is raw
263 res = erasure(res);
264 } else {
265 // Unbound type arguments default to ?
266 List<Type> opens = openVars.toList();
267 ListBuffer<Type> qs = new ListBuffer<Type>();
268 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
269 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head));
270 }
271 res = subst(res, opens, qs.toList());
272 }
273 }
274 return res;
275 }
277 @Override
278 public Type visitErrorType(ErrorType t, Symbol sym) {
279 return t;
280 }
281 };
282 // </editor-fold>
284 // <editor-fold defaultstate="collapsed" desc="isConvertible">
285 /**
286 * Is t a subtype of or convertible via boxing/unboxing
287 * conversion to s?
288 */
289 public boolean isConvertible(Type t, Type s, Warner warn) {
290 if (t.tag == ERROR)
291 return true;
292 boolean tPrimitive = t.isPrimitive();
293 boolean sPrimitive = s.isPrimitive();
294 if (tPrimitive == sPrimitive) {
295 return isSubtypeUnchecked(t, s, warn);
296 }
297 if (!allowBoxing) return false;
298 return tPrimitive
299 ? isSubtype(boxedClass(t).type, s)
300 : isSubtype(unboxedType(t), s);
301 }
303 /**
304 * Is t a subtype of or convertiable via boxing/unboxing
305 * convertions to s?
306 */
307 public boolean isConvertible(Type t, Type s) {
308 return isConvertible(t, s, noWarnings);
309 }
310 // </editor-fold>
312 // <editor-fold defaultstate="collapsed" desc="findSam">
314 /**
315 * Exception used to report a function descriptor lookup failure. The exception
316 * wraps a diagnostic that can be used to generate more details error
317 * messages.
318 */
319 public static class FunctionDescriptorLookupError extends RuntimeException {
320 private static final long serialVersionUID = 0;
322 JCDiagnostic diagnostic;
324 FunctionDescriptorLookupError() {
325 this.diagnostic = null;
326 }
328 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
329 this.diagnostic = diag;
330 return this;
331 }
333 public JCDiagnostic getDiagnostic() {
334 return diagnostic;
335 }
336 }
338 /**
339 * A cache that keeps track of function descriptors associated with given
340 * functional interfaces.
341 */
342 class DescriptorCache {
344 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<TypeSymbol, Entry>();
346 class FunctionDescriptor {
347 Symbol descSym;
349 FunctionDescriptor(Symbol descSym) {
350 this.descSym = descSym;
351 }
353 public Symbol getSymbol() {
354 return descSym;
355 }
357 public Type getType(Type origin) {
358 return memberType(origin, descSym);
359 }
360 }
362 class Entry {
363 final FunctionDescriptor cachedDescRes;
364 final int prevMark;
366 public Entry(FunctionDescriptor cachedDescRes,
367 int prevMark) {
368 this.cachedDescRes = cachedDescRes;
369 this.prevMark = prevMark;
370 }
372 boolean matches(int mark) {
373 return this.prevMark == mark;
374 }
375 }
377 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
378 Entry e = _map.get(origin);
379 CompoundScope members = membersClosure(origin.type, false);
380 if (e == null ||
381 !e.matches(members.getMark())) {
382 FunctionDescriptor descRes = findDescriptorInternal(origin, members);
383 _map.put(origin, new Entry(descRes, members.getMark()));
384 return descRes;
385 }
386 else {
387 return e.cachedDescRes;
388 }
389 }
391 /**
392 * Scope filter used to skip methods that should be ignored during
393 * function interface conversion (such as methods overridden by
394 * j.l.Object)
395 */
396 class DescriptorFilter implements Filter<Symbol> {
398 TypeSymbol origin;
400 DescriptorFilter(TypeSymbol origin) {
401 this.origin = origin;
402 }
404 @Override
405 public boolean accepts(Symbol sym) {
406 return sym.kind == Kinds.MTH &&
407 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
408 !overridesObjectMethod(origin, sym) &&
409 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
410 }
411 };
413 /**
414 * Compute the function descriptor associated with a given functional interface
415 */
416 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin, CompoundScope membersCache) throws FunctionDescriptorLookupError {
417 if (!origin.isInterface()) {
418 //t must be an interface
419 throw failure("not.a.functional.intf");
420 }
422 final ListBuffer<Symbol> abstracts = ListBuffer.lb();
423 for (Symbol sym : membersCache.getElements(new DescriptorFilter(origin))) {
424 Type mtype = memberType(origin.type, sym);
425 if (abstracts.isEmpty() ||
426 (sym.name == abstracts.first().name &&
427 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
428 abstracts.append(sym);
429 } else {
430 //the target method(s) should be the only abstract members of t
431 throw failure("not.a.functional.intf.1",
432 diags.fragment("incompatible.abstracts", Kinds.kindName(origin), origin));
433 }
434 }
435 if (abstracts.isEmpty()) {
436 //t must define a suitable non-generic method
437 throw failure("not.a.functional.intf.1",
438 diags.fragment("no.abstracts", Kinds.kindName(origin), origin));
439 } else if (abstracts.size() == 1) {
440 if (abstracts.first().type.tag == FORALL) {
441 throw failure("invalid.generic.desc.in.functional.intf",
442 abstracts.first(),
443 Kinds.kindName(origin),
444 origin);
445 } else {
446 return new FunctionDescriptor(abstracts.first());
447 }
448 } else { // size > 1
449 for (Symbol msym : abstracts) {
450 if (msym.type.tag == FORALL) {
451 throw failure("invalid.generic.desc.in.functional.intf",
452 abstracts.first(),
453 Kinds.kindName(origin),
454 origin);
455 }
456 }
457 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
458 if (descRes == null) {
459 //we can get here if the functional interface is ill-formed
460 ListBuffer<JCDiagnostic> descriptors = ListBuffer.lb();
461 for (Symbol desc : abstracts) {
462 String key = desc.type.getThrownTypes().nonEmpty() ?
463 "descriptor.throws" : "descriptor";
464 descriptors.append(diags.fragment(key, desc.name,
465 desc.type.getParameterTypes(),
466 desc.type.getReturnType(),
467 desc.type.getThrownTypes()));
468 }
469 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
470 new JCDiagnostic.MultilineDiagnostic(diags.fragment("incompatible.descs.in.functional.intf",
471 Kinds.kindName(origin), origin), descriptors.toList());
472 throw failure(incompatibleDescriptors);
473 }
474 return descRes;
475 }
476 }
478 /**
479 * Compute a synthetic type for the target descriptor given a list
480 * of override-equivalent methods in the functional interface type.
481 * The resulting method type is a method type that is override-equivalent
482 * and return-type substitutable with each method in the original list.
483 */
484 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
485 //pick argument types - simply take the signature that is a
486 //subsignature of all other signatures in the list (as per JLS 8.4.2)
487 List<Symbol> mostSpecific = List.nil();
488 outer: for (Symbol msym1 : methodSyms) {
489 Type mt1 = memberType(origin.type, msym1);
490 for (Symbol msym2 : methodSyms) {
491 Type mt2 = memberType(origin.type, msym2);
492 if (!isSubSignature(mt1, mt2)) {
493 continue outer;
494 }
495 }
496 mostSpecific = mostSpecific.prepend(msym1);
497 }
498 if (mostSpecific.isEmpty()) {
499 return null;
500 }
503 //pick return types - this is done in two phases: (i) first, the most
504 //specific return type is chosen using strict subtyping; if this fails,
505 //a second attempt is made using return type substitutability (see JLS 8.4.5)
506 boolean phase2 = false;
507 Symbol bestSoFar = null;
508 while (bestSoFar == null) {
509 outer: for (Symbol msym1 : mostSpecific) {
510 Type mt1 = memberType(origin.type, msym1);
511 for (Symbol msym2 : methodSyms) {
512 Type mt2 = memberType(origin.type, msym2);
513 if (phase2 ?
514 !returnTypeSubstitutable(mt1, mt2) :
515 !isSubtypeInternal(mt1.getReturnType(), mt2.getReturnType())) {
516 continue outer;
517 }
518 }
519 bestSoFar = msym1;
520 }
521 if (phase2) {
522 break;
523 } else {
524 phase2 = true;
525 }
526 }
527 if (bestSoFar == null) return null;
529 //merge thrown types - form the intersection of all the thrown types in
530 //all the signatures in the list
531 List<Type> thrown = null;
532 for (Symbol msym1 : methodSyms) {
533 Type mt1 = memberType(origin.type, msym1);
534 thrown = (thrown == null) ?
535 mt1.getThrownTypes() :
536 chk.intersect(mt1.getThrownTypes(), thrown);
537 }
539 final List<Type> thrown1 = thrown;
540 return new FunctionDescriptor(bestSoFar) {
541 @Override
542 public Type getType(Type origin) {
543 Type mt = memberType(origin, getSymbol());
544 return new MethodType(mt.getParameterTypes(), mt.getReturnType(), thrown1, syms.methodClass);
545 }
546 };
547 }
549 boolean isSubtypeInternal(Type s, Type t) {
550 return (s.isPrimitive() && t.isPrimitive()) ?
551 isSameType(t, s) :
552 isSubtype(s, t);
553 }
555 FunctionDescriptorLookupError failure(String msg, Object... args) {
556 return failure(diags.fragment(msg, args));
557 }
559 FunctionDescriptorLookupError failure(JCDiagnostic diag) {
560 return functionDescriptorLookupError.setMessage(diag);
561 }
562 }
564 private DescriptorCache descCache = new DescriptorCache();
566 /**
567 * Find the method descriptor associated to this class symbol - if the
568 * symbol 'origin' is not a functional interface, an exception is thrown.
569 */
570 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
571 return descCache.get(origin).getSymbol();
572 }
574 /**
575 * Find the type of the method descriptor associated to this class symbol -
576 * if the symbol 'origin' is not a functional interface, an exception is thrown.
577 */
578 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
579 return descCache.get(origin.tsym).getType(origin);
580 }
582 /**
583 * Is given type a functional interface?
584 */
585 public boolean isFunctionalInterface(TypeSymbol tsym) {
586 try {
587 findDescriptorSymbol(tsym);
588 return true;
589 } catch (FunctionDescriptorLookupError ex) {
590 return false;
591 }
592 }
593 // </editor-fold>
595 // <editor-fold defaultstate="collapsed" desc="isSubtype">
596 /**
597 * Is t an unchecked subtype of s?
598 */
599 public boolean isSubtypeUnchecked(Type t, Type s) {
600 return isSubtypeUnchecked(t, s, noWarnings);
601 }
602 /**
603 * Is t an unchecked subtype of s?
604 */
605 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
606 boolean result = isSubtypeUncheckedInternal(t, s, warn);
607 if (result) {
608 checkUnsafeVarargsConversion(t, s, warn);
609 }
610 return result;
611 }
612 //where
613 private boolean isSubtypeUncheckedInternal(Type t, Type s, Warner warn) {
614 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
615 if (((ArrayType)t).elemtype.isPrimitive()) {
616 return isSameType(elemtype(t), elemtype(s));
617 } else {
618 return isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
619 }
620 } else if (isSubtype(t, s)) {
621 return true;
622 }
623 else if (t.tag == TYPEVAR) {
624 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
625 }
626 else if (!s.isRaw()) {
627 Type t2 = asSuper(t, s.tsym);
628 if (t2 != null && t2.isRaw()) {
629 if (isReifiable(s))
630 warn.silentWarn(LintCategory.UNCHECKED);
631 else
632 warn.warn(LintCategory.UNCHECKED);
633 return true;
634 }
635 }
636 return false;
637 }
639 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
640 if (t.tag != ARRAY || isReifiable(t)) return;
641 ArrayType from = (ArrayType)t;
642 boolean shouldWarn = false;
643 switch (s.tag) {
644 case ARRAY:
645 ArrayType to = (ArrayType)s;
646 shouldWarn = from.isVarargs() &&
647 !to.isVarargs() &&
648 !isReifiable(from);
649 break;
650 case CLASS:
651 shouldWarn = from.isVarargs();
652 break;
653 }
654 if (shouldWarn) {
655 warn.warn(LintCategory.VARARGS);
656 }
657 }
659 /**
660 * Is t a subtype of s?<br>
661 * (not defined for Method and ForAll types)
662 */
663 final public boolean isSubtype(Type t, Type s) {
664 return isSubtype(t, s, true);
665 }
666 final public boolean isSubtypeNoCapture(Type t, Type s) {
667 return isSubtype(t, s, false);
668 }
669 public boolean isSubtype(Type t, Type s, boolean capture) {
670 if (t == s)
671 return true;
673 if (s.isPartial())
674 return isSuperType(s, t);
676 if (s.isCompound()) {
677 for (Type s2 : interfaces(s).prepend(supertype(s))) {
678 if (!isSubtype(t, s2, capture))
679 return false;
680 }
681 return true;
682 }
684 Type lower = lowerBound(s);
685 if (s != lower)
686 return isSubtype(capture ? capture(t) : t, lower, false);
688 return isSubtype.visit(capture ? capture(t) : t, s);
689 }
690 // where
691 private TypeRelation isSubtype = new TypeRelation()
692 {
693 public Boolean visitType(Type t, Type s) {
694 switch (t.tag) {
695 case BYTE:
696 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
697 case CHAR:
698 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
699 case SHORT: case INT: case LONG:
700 case FLOAT: case DOUBLE:
701 return t.getTag().isSubRangeOf(s.getTag());
702 case BOOLEAN: case VOID:
703 return t.hasTag(s.getTag());
704 case TYPEVAR:
705 return isSubtypeNoCapture(t.getUpperBound(), s);
706 case BOT:
707 return
708 s.hasTag(BOT) || s.hasTag(CLASS) ||
709 s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
710 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
711 case NONE:
712 return false;
713 default:
714 throw new AssertionError("isSubtype " + t.tag);
715 }
716 }
718 private Set<TypePair> cache = new HashSet<TypePair>();
720 private boolean containsTypeRecursive(Type t, Type s) {
721 TypePair pair = new TypePair(t, s);
722 if (cache.add(pair)) {
723 try {
724 return containsType(t.getTypeArguments(),
725 s.getTypeArguments());
726 } finally {
727 cache.remove(pair);
728 }
729 } else {
730 return containsType(t.getTypeArguments(),
731 rewriteSupers(s).getTypeArguments());
732 }
733 }
735 private Type rewriteSupers(Type t) {
736 if (!t.isParameterized())
737 return t;
738 ListBuffer<Type> from = lb();
739 ListBuffer<Type> to = lb();
740 adaptSelf(t, from, to);
741 if (from.isEmpty())
742 return t;
743 ListBuffer<Type> rewrite = lb();
744 boolean changed = false;
745 for (Type orig : to.toList()) {
746 Type s = rewriteSupers(orig);
747 if (s.isSuperBound() && !s.isExtendsBound()) {
748 s = new WildcardType(syms.objectType,
749 BoundKind.UNBOUND,
750 syms.boundClass);
751 changed = true;
752 } else if (s != orig) {
753 s = new WildcardType(upperBound(s),
754 BoundKind.EXTENDS,
755 syms.boundClass);
756 changed = true;
757 }
758 rewrite.append(s);
759 }
760 if (changed)
761 return subst(t.tsym.type, from.toList(), rewrite.toList());
762 else
763 return t;
764 }
766 @Override
767 public Boolean visitClassType(ClassType t, Type s) {
768 Type sup = asSuper(t, s.tsym);
769 return sup != null
770 && sup.tsym == s.tsym
771 // You're not allowed to write
772 // Vector<Object> vec = new Vector<String>();
773 // But with wildcards you can write
774 // Vector<? extends Object> vec = new Vector<String>();
775 // which means that subtype checking must be done
776 // here instead of same-type checking (via containsType).
777 && (!s.isParameterized() || containsTypeRecursive(s, sup))
778 && isSubtypeNoCapture(sup.getEnclosingType(),
779 s.getEnclosingType());
780 }
782 @Override
783 public Boolean visitArrayType(ArrayType t, Type s) {
784 if (s.tag == ARRAY) {
785 if (t.elemtype.isPrimitive())
786 return isSameType(t.elemtype, elemtype(s));
787 else
788 return isSubtypeNoCapture(t.elemtype, elemtype(s));
789 }
791 if (s.tag == CLASS) {
792 Name sname = s.tsym.getQualifiedName();
793 return sname == names.java_lang_Object
794 || sname == names.java_lang_Cloneable
795 || sname == names.java_io_Serializable;
796 }
798 return false;
799 }
801 @Override
802 public Boolean visitUndetVar(UndetVar t, Type s) {
803 //todo: test against origin needed? or replace with substitution?
804 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN) {
805 return true;
806 } else if (s.tag == BOT) {
807 //if 's' is 'null' there's no instantiated type U for which
808 //U <: s (but 'null' itself, which is not a valid type)
809 return false;
810 }
812 t.addBound(InferenceBound.UPPER, s, Types.this);
813 return true;
814 }
816 @Override
817 public Boolean visitErrorType(ErrorType t, Type s) {
818 return true;
819 }
820 };
822 /**
823 * Is t a subtype of every type in given list `ts'?<br>
824 * (not defined for Method and ForAll types)<br>
825 * Allows unchecked conversions.
826 */
827 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
828 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
829 if (!isSubtypeUnchecked(t, l.head, warn))
830 return false;
831 return true;
832 }
834 /**
835 * Are corresponding elements of ts subtypes of ss? If lists are
836 * of different length, return false.
837 */
838 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
839 while (ts.tail != null && ss.tail != null
840 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
841 isSubtype(ts.head, ss.head)) {
842 ts = ts.tail;
843 ss = ss.tail;
844 }
845 return ts.tail == null && ss.tail == null;
846 /*inlined: ts.isEmpty() && ss.isEmpty();*/
847 }
849 /**
850 * Are corresponding elements of ts subtypes of ss, allowing
851 * unchecked conversions? If lists are of different length,
852 * return false.
853 **/
854 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
855 while (ts.tail != null && ss.tail != null
856 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
857 isSubtypeUnchecked(ts.head, ss.head, warn)) {
858 ts = ts.tail;
859 ss = ss.tail;
860 }
861 return ts.tail == null && ss.tail == null;
862 /*inlined: ts.isEmpty() && ss.isEmpty();*/
863 }
864 // </editor-fold>
866 // <editor-fold defaultstate="collapsed" desc="isSuperType">
867 /**
868 * Is t a supertype of s?
869 */
870 public boolean isSuperType(Type t, Type s) {
871 switch (t.tag) {
872 case ERROR:
873 return true;
874 case UNDETVAR: {
875 UndetVar undet = (UndetVar)t;
876 if (t == s ||
877 undet.qtype == s ||
878 s.tag == ERROR ||
879 s.tag == BOT) return true;
880 undet.addBound(InferenceBound.LOWER, s, this);
881 return true;
882 }
883 default:
884 return isSubtype(s, t);
885 }
886 }
887 // </editor-fold>
889 // <editor-fold defaultstate="collapsed" desc="isSameType">
890 /**
891 * Are corresponding elements of the lists the same type? If
892 * lists are of different length, return false.
893 */
894 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
895 while (ts.tail != null && ss.tail != null
896 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
897 isSameType(ts.head, ss.head)) {
898 ts = ts.tail;
899 ss = ss.tail;
900 }
901 return ts.tail == null && ss.tail == null;
902 /*inlined: ts.isEmpty() && ss.isEmpty();*/
903 }
905 /**
906 * Is t the same type as s?
907 */
908 public boolean isSameType(Type t, Type s) {
909 return isSameType.visit(t, s);
910 }
911 // where
912 private TypeRelation isSameType = new TypeRelation() {
914 public Boolean visitType(Type t, Type s) {
915 if (t == s)
916 return true;
918 if (s.isPartial())
919 return visit(s, t);
921 switch (t.tag) {
922 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
923 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
924 return t.tag == s.tag;
925 case TYPEVAR: {
926 if (s.tag == TYPEVAR) {
927 //type-substitution does not preserve type-var types
928 //check that type var symbols and bounds are indeed the same
929 return t.tsym == s.tsym &&
930 visit(t.getUpperBound(), s.getUpperBound());
931 }
932 else {
933 //special case for s == ? super X, where upper(s) = u
934 //check that u == t, where u has been set by Type.withTypeVar
935 return s.isSuperBound() &&
936 !s.isExtendsBound() &&
937 visit(t, upperBound(s));
938 }
939 }
940 default:
941 throw new AssertionError("isSameType " + t.tag);
942 }
943 }
945 @Override
946 public Boolean visitWildcardType(WildcardType t, Type s) {
947 if (s.isPartial())
948 return visit(s, t);
949 else
950 return false;
951 }
953 @Override
954 public Boolean visitClassType(ClassType t, Type s) {
955 if (t == s)
956 return true;
958 if (s.isPartial())
959 return visit(s, t);
961 if (s.isSuperBound() && !s.isExtendsBound())
962 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
964 if (t.isCompound() && s.isCompound()) {
965 if (!visit(supertype(t), supertype(s)))
966 return false;
968 HashSet<SingletonType> set = new HashSet<SingletonType>();
969 for (Type x : interfaces(t))
970 set.add(new SingletonType(x));
971 for (Type x : interfaces(s)) {
972 if (!set.remove(new SingletonType(x)))
973 return false;
974 }
975 return (set.isEmpty());
976 }
977 return t.tsym == s.tsym
978 && visit(t.getEnclosingType(), s.getEnclosingType())
979 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
980 }
982 @Override
983 public Boolean visitArrayType(ArrayType t, Type s) {
984 if (t == s)
985 return true;
987 if (s.isPartial())
988 return visit(s, t);
990 return s.hasTag(ARRAY)
991 && containsTypeEquivalent(t.elemtype, elemtype(s));
992 }
994 @Override
995 public Boolean visitMethodType(MethodType t, Type s) {
996 // isSameType for methods does not take thrown
997 // exceptions into account!
998 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
999 }
1001 @Override
1002 public Boolean visitPackageType(PackageType t, Type s) {
1003 return t == s;
1004 }
1006 @Override
1007 public Boolean visitForAll(ForAll t, Type s) {
1008 if (s.tag != FORALL)
1009 return false;
1011 ForAll forAll = (ForAll)s;
1012 return hasSameBounds(t, forAll)
1013 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1014 }
1016 @Override
1017 public Boolean visitUndetVar(UndetVar t, Type s) {
1018 if (s.tag == WILDCARD)
1019 // FIXME, this might be leftovers from before capture conversion
1020 return false;
1022 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
1023 return true;
1025 t.addBound(InferenceBound.EQ, s, Types.this);
1027 return true;
1028 }
1030 @Override
1031 public Boolean visitErrorType(ErrorType t, Type s) {
1032 return true;
1033 }
1034 };
1035 // </editor-fold>
1037 // <editor-fold defaultstate="collapsed" desc="Contains Type">
1038 public boolean containedBy(Type t, Type s) {
1039 switch (t.tag) {
1040 case UNDETVAR:
1041 if (s.tag == WILDCARD) {
1042 UndetVar undetvar = (UndetVar)t;
1043 WildcardType wt = (WildcardType)s;
1044 switch(wt.kind) {
1045 case UNBOUND: //similar to ? extends Object
1046 case EXTENDS: {
1047 Type bound = upperBound(s);
1048 undetvar.addBound(InferenceBound.UPPER, bound, this);
1049 break;
1050 }
1051 case SUPER: {
1052 Type bound = lowerBound(s);
1053 undetvar.addBound(InferenceBound.LOWER, bound, this);
1054 break;
1055 }
1056 }
1057 return true;
1058 } else {
1059 return isSameType(t, s);
1060 }
1061 case ERROR:
1062 return true;
1063 default:
1064 return containsType(s, t);
1065 }
1066 }
1068 boolean containsType(List<Type> ts, List<Type> ss) {
1069 while (ts.nonEmpty() && ss.nonEmpty()
1070 && containsType(ts.head, ss.head)) {
1071 ts = ts.tail;
1072 ss = ss.tail;
1073 }
1074 return ts.isEmpty() && ss.isEmpty();
1075 }
1077 /**
1078 * Check if t contains s.
1079 *
1080 * <p>T contains S if:
1081 *
1082 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
1083 *
1084 * <p>This relation is only used by ClassType.isSubtype(), that
1085 * is,
1086 *
1087 * <p>{@code C<S> <: C<T> if T contains S.}
1088 *
1089 * <p>Because of F-bounds, this relation can lead to infinite
1090 * recursion. Thus we must somehow break that recursion. Notice
1091 * that containsType() is only called from ClassType.isSubtype().
1092 * Since the arguments have already been checked against their
1093 * bounds, we know:
1094 *
1095 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
1096 *
1097 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
1098 *
1099 * @param t a type
1100 * @param s a type
1101 */
1102 public boolean containsType(Type t, Type s) {
1103 return containsType.visit(t, s);
1104 }
1105 // where
1106 private TypeRelation containsType = new TypeRelation() {
1108 private Type U(Type t) {
1109 while (t.tag == WILDCARD) {
1110 WildcardType w = (WildcardType)t;
1111 if (w.isSuperBound())
1112 return w.bound == null ? syms.objectType : w.bound.bound;
1113 else
1114 t = w.type;
1115 }
1116 return t;
1117 }
1119 private Type L(Type t) {
1120 while (t.tag == WILDCARD) {
1121 WildcardType w = (WildcardType)t;
1122 if (w.isExtendsBound())
1123 return syms.botType;
1124 else
1125 t = w.type;
1126 }
1127 return t;
1128 }
1130 public Boolean visitType(Type t, Type s) {
1131 if (s.isPartial())
1132 return containedBy(s, t);
1133 else
1134 return isSameType(t, s);
1135 }
1137 // void debugContainsType(WildcardType t, Type s) {
1138 // System.err.println();
1139 // System.err.format(" does %s contain %s?%n", t, s);
1140 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
1141 // upperBound(s), s, t, U(t),
1142 // t.isSuperBound()
1143 // || isSubtypeNoCapture(upperBound(s), U(t)));
1144 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
1145 // L(t), t, s, lowerBound(s),
1146 // t.isExtendsBound()
1147 // || isSubtypeNoCapture(L(t), lowerBound(s)));
1148 // System.err.println();
1149 // }
1151 @Override
1152 public Boolean visitWildcardType(WildcardType t, Type s) {
1153 if (s.isPartial())
1154 return containedBy(s, t);
1155 else {
1156 // debugContainsType(t, s);
1157 return isSameWildcard(t, s)
1158 || isCaptureOf(s, t)
1159 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
1160 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
1161 }
1162 }
1164 @Override
1165 public Boolean visitUndetVar(UndetVar t, Type s) {
1166 if (s.tag != WILDCARD)
1167 return isSameType(t, s);
1168 else
1169 return false;
1170 }
1172 @Override
1173 public Boolean visitErrorType(ErrorType t, Type s) {
1174 return true;
1175 }
1176 };
1178 public boolean isCaptureOf(Type s, WildcardType t) {
1179 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
1180 return false;
1181 return isSameWildcard(t, ((CapturedType)s).wildcard);
1182 }
1184 public boolean isSameWildcard(WildcardType t, Type s) {
1185 if (s.tag != WILDCARD)
1186 return false;
1187 WildcardType w = (WildcardType)s;
1188 return w.kind == t.kind && w.type == t.type;
1189 }
1191 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
1192 while (ts.nonEmpty() && ss.nonEmpty()
1193 && containsTypeEquivalent(ts.head, ss.head)) {
1194 ts = ts.tail;
1195 ss = ss.tail;
1196 }
1197 return ts.isEmpty() && ss.isEmpty();
1198 }
1199 // </editor-fold>
1201 // <editor-fold defaultstate="collapsed" desc="isCastable">
1202 public boolean isCastable(Type t, Type s) {
1203 return isCastable(t, s, noWarnings);
1204 }
1206 /**
1207 * Is t is castable to s?<br>
1208 * s is assumed to be an erased type.<br>
1209 * (not defined for Method and ForAll types).
1210 */
1211 public boolean isCastable(Type t, Type s, Warner warn) {
1212 if (t == s)
1213 return true;
1215 if (t.isPrimitive() != s.isPrimitive())
1216 return allowBoxing && (
1217 isConvertible(t, s, warn)
1218 || (allowObjectToPrimitiveCast &&
1219 s.isPrimitive() &&
1220 isSubtype(boxedClass(s).type, t)));
1221 if (warn != warnStack.head) {
1222 try {
1223 warnStack = warnStack.prepend(warn);
1224 checkUnsafeVarargsConversion(t, s, warn);
1225 return isCastable.visit(t,s);
1226 } finally {
1227 warnStack = warnStack.tail;
1228 }
1229 } else {
1230 return isCastable.visit(t,s);
1231 }
1232 }
1233 // where
1234 private TypeRelation isCastable = new TypeRelation() {
1236 public Boolean visitType(Type t, Type s) {
1237 if (s.tag == ERROR)
1238 return true;
1240 switch (t.tag) {
1241 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
1242 case DOUBLE:
1243 return s.isNumeric();
1244 case BOOLEAN:
1245 return s.tag == BOOLEAN;
1246 case VOID:
1247 return false;
1248 case BOT:
1249 return isSubtype(t, s);
1250 default:
1251 throw new AssertionError();
1252 }
1253 }
1255 @Override
1256 public Boolean visitWildcardType(WildcardType t, Type s) {
1257 return isCastable(upperBound(t), s, warnStack.head);
1258 }
1260 @Override
1261 public Boolean visitClassType(ClassType t, Type s) {
1262 if (s.tag == ERROR || s.tag == BOT)
1263 return true;
1265 if (s.tag == TYPEVAR) {
1266 if (isCastable(t, s.getUpperBound(), noWarnings)) {
1267 warnStack.head.warn(LintCategory.UNCHECKED);
1268 return true;
1269 } else {
1270 return false;
1271 }
1272 }
1274 if (t.isCompound()) {
1275 Warner oldWarner = warnStack.head;
1276 warnStack.head = noWarnings;
1277 if (!visit(supertype(t), s))
1278 return false;
1279 for (Type intf : interfaces(t)) {
1280 if (!visit(intf, s))
1281 return false;
1282 }
1283 if (warnStack.head.hasLint(LintCategory.UNCHECKED))
1284 oldWarner.warn(LintCategory.UNCHECKED);
1285 return true;
1286 }
1288 if (s.isCompound()) {
1289 // call recursively to reuse the above code
1290 return visitClassType((ClassType)s, t);
1291 }
1293 if (s.tag == CLASS || s.tag == ARRAY) {
1294 boolean upcast;
1295 if ((upcast = isSubtype(erasure(t), erasure(s)))
1296 || isSubtype(erasure(s), erasure(t))) {
1297 if (!upcast && s.tag == ARRAY) {
1298 if (!isReifiable(s))
1299 warnStack.head.warn(LintCategory.UNCHECKED);
1300 return true;
1301 } else if (s.isRaw()) {
1302 return true;
1303 } else if (t.isRaw()) {
1304 if (!isUnbounded(s))
1305 warnStack.head.warn(LintCategory.UNCHECKED);
1306 return true;
1307 }
1308 // Assume |a| <: |b|
1309 final Type a = upcast ? t : s;
1310 final Type b = upcast ? s : t;
1311 final boolean HIGH = true;
1312 final boolean LOW = false;
1313 final boolean DONT_REWRITE_TYPEVARS = false;
1314 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1315 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1316 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1317 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1318 Type lowSub = asSub(bLow, aLow.tsym);
1319 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1320 if (highSub == null) {
1321 final boolean REWRITE_TYPEVARS = true;
1322 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1323 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1324 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1325 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1326 lowSub = asSub(bLow, aLow.tsym);
1327 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1328 }
1329 if (highSub != null) {
1330 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1331 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1332 }
1333 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1334 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1335 && !disjointTypes(aLow.allparams(), highSub.allparams())
1336 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1337 if (upcast ? giveWarning(a, b) :
1338 giveWarning(b, a))
1339 warnStack.head.warn(LintCategory.UNCHECKED);
1340 return true;
1341 }
1342 }
1343 if (isReifiable(s))
1344 return isSubtypeUnchecked(a, b);
1345 else
1346 return isSubtypeUnchecked(a, b, warnStack.head);
1347 }
1349 // Sidecast
1350 if (s.tag == CLASS) {
1351 if ((s.tsym.flags() & INTERFACE) != 0) {
1352 return ((t.tsym.flags() & FINAL) == 0)
1353 ? sideCast(t, s, warnStack.head)
1354 : sideCastFinal(t, s, warnStack.head);
1355 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1356 return ((s.tsym.flags() & FINAL) == 0)
1357 ? sideCast(t, s, warnStack.head)
1358 : sideCastFinal(t, s, warnStack.head);
1359 } else {
1360 // unrelated class types
1361 return false;
1362 }
1363 }
1364 }
1365 return false;
1366 }
1368 @Override
1369 public Boolean visitArrayType(ArrayType t, Type s) {
1370 switch (s.tag) {
1371 case ERROR:
1372 case BOT:
1373 return true;
1374 case TYPEVAR:
1375 if (isCastable(s, t, noWarnings)) {
1376 warnStack.head.warn(LintCategory.UNCHECKED);
1377 return true;
1378 } else {
1379 return false;
1380 }
1381 case CLASS:
1382 return isSubtype(t, s);
1383 case ARRAY:
1384 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
1385 return elemtype(t).tag == elemtype(s).tag;
1386 } else {
1387 return visit(elemtype(t), elemtype(s));
1388 }
1389 default:
1390 return false;
1391 }
1392 }
1394 @Override
1395 public Boolean visitTypeVar(TypeVar t, Type s) {
1396 switch (s.tag) {
1397 case ERROR:
1398 case BOT:
1399 return true;
1400 case TYPEVAR:
1401 if (isSubtype(t, s)) {
1402 return true;
1403 } else if (isCastable(t.bound, s, noWarnings)) {
1404 warnStack.head.warn(LintCategory.UNCHECKED);
1405 return true;
1406 } else {
1407 return false;
1408 }
1409 default:
1410 return isCastable(t.bound, s, warnStack.head);
1411 }
1412 }
1414 @Override
1415 public Boolean visitErrorType(ErrorType t, Type s) {
1416 return true;
1417 }
1418 };
1419 // </editor-fold>
1421 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1422 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1423 while (ts.tail != null && ss.tail != null) {
1424 if (disjointType(ts.head, ss.head)) return true;
1425 ts = ts.tail;
1426 ss = ss.tail;
1427 }
1428 return false;
1429 }
1431 /**
1432 * Two types or wildcards are considered disjoint if it can be
1433 * proven that no type can be contained in both. It is
1434 * conservative in that it is allowed to say that two types are
1435 * not disjoint, even though they actually are.
1436 *
1437 * The type {@code C<X>} is castable to {@code C<Y>} exactly if
1438 * {@code X} and {@code Y} are not disjoint.
1439 */
1440 public boolean disjointType(Type t, Type s) {
1441 return disjointType.visit(t, s);
1442 }
1443 // where
1444 private TypeRelation disjointType = new TypeRelation() {
1446 private Set<TypePair> cache = new HashSet<TypePair>();
1448 public Boolean visitType(Type t, Type s) {
1449 if (s.tag == WILDCARD)
1450 return visit(s, t);
1451 else
1452 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1453 }
1455 private boolean isCastableRecursive(Type t, Type s) {
1456 TypePair pair = new TypePair(t, s);
1457 if (cache.add(pair)) {
1458 try {
1459 return Types.this.isCastable(t, s);
1460 } finally {
1461 cache.remove(pair);
1462 }
1463 } else {
1464 return true;
1465 }
1466 }
1468 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1469 TypePair pair = new TypePair(t, s);
1470 if (cache.add(pair)) {
1471 try {
1472 return Types.this.notSoftSubtype(t, s);
1473 } finally {
1474 cache.remove(pair);
1475 }
1476 } else {
1477 return false;
1478 }
1479 }
1481 @Override
1482 public Boolean visitWildcardType(WildcardType t, Type s) {
1483 if (t.isUnbound())
1484 return false;
1486 if (s.tag != WILDCARD) {
1487 if (t.isExtendsBound())
1488 return notSoftSubtypeRecursive(s, t.type);
1489 else // isSuperBound()
1490 return notSoftSubtypeRecursive(t.type, s);
1491 }
1493 if (s.isUnbound())
1494 return false;
1496 if (t.isExtendsBound()) {
1497 if (s.isExtendsBound())
1498 return !isCastableRecursive(t.type, upperBound(s));
1499 else if (s.isSuperBound())
1500 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1501 } else if (t.isSuperBound()) {
1502 if (s.isExtendsBound())
1503 return notSoftSubtypeRecursive(t.type, upperBound(s));
1504 }
1505 return false;
1506 }
1507 };
1508 // </editor-fold>
1510 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1511 /**
1512 * Returns the lower bounds of the formals of a method.
1513 */
1514 public List<Type> lowerBoundArgtypes(Type t) {
1515 return lowerBounds(t.getParameterTypes());
1516 }
1517 public List<Type> lowerBounds(List<Type> ts) {
1518 return map(ts, lowerBoundMapping);
1519 }
1520 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1521 public Type apply(Type t) {
1522 return lowerBound(t);
1523 }
1524 };
1525 // </editor-fold>
1527 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1528 /**
1529 * This relation answers the question: is impossible that
1530 * something of type `t' can be a subtype of `s'? This is
1531 * different from the question "is `t' not a subtype of `s'?"
1532 * when type variables are involved: Integer is not a subtype of T
1533 * where {@code <T extends Number>} but it is not true that Integer cannot
1534 * possibly be a subtype of T.
1535 */
1536 public boolean notSoftSubtype(Type t, Type s) {
1537 if (t == s) return false;
1538 if (t.tag == TYPEVAR) {
1539 TypeVar tv = (TypeVar) t;
1540 return !isCastable(tv.bound,
1541 relaxBound(s),
1542 noWarnings);
1543 }
1544 if (s.tag != WILDCARD)
1545 s = upperBound(s);
1547 return !isSubtype(t, relaxBound(s));
1548 }
1550 private Type relaxBound(Type t) {
1551 if (t.tag == TYPEVAR) {
1552 while (t.tag == TYPEVAR)
1553 t = t.getUpperBound();
1554 t = rewriteQuantifiers(t, true, true);
1555 }
1556 return t;
1557 }
1558 // </editor-fold>
1560 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1561 public boolean isReifiable(Type t) {
1562 return isReifiable.visit(t);
1563 }
1564 // where
1565 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1567 public Boolean visitType(Type t, Void ignored) {
1568 return true;
1569 }
1571 @Override
1572 public Boolean visitClassType(ClassType t, Void ignored) {
1573 if (t.isCompound())
1574 return false;
1575 else {
1576 if (!t.isParameterized())
1577 return true;
1579 for (Type param : t.allparams()) {
1580 if (!param.isUnbound())
1581 return false;
1582 }
1583 return true;
1584 }
1585 }
1587 @Override
1588 public Boolean visitArrayType(ArrayType t, Void ignored) {
1589 return visit(t.elemtype);
1590 }
1592 @Override
1593 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1594 return false;
1595 }
1596 };
1597 // </editor-fold>
1599 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1600 public boolean isArray(Type t) {
1601 while (t.tag == WILDCARD)
1602 t = upperBound(t);
1603 return t.tag == ARRAY;
1604 }
1606 /**
1607 * The element type of an array.
1608 */
1609 public Type elemtype(Type t) {
1610 switch (t.tag) {
1611 case WILDCARD:
1612 return elemtype(upperBound(t));
1613 case ARRAY:
1614 return ((ArrayType)t).elemtype;
1615 case FORALL:
1616 return elemtype(((ForAll)t).qtype);
1617 case ERROR:
1618 return t;
1619 default:
1620 return null;
1621 }
1622 }
1624 public Type elemtypeOrType(Type t) {
1625 Type elemtype = elemtype(t);
1626 return elemtype != null ?
1627 elemtype :
1628 t;
1629 }
1631 /**
1632 * Mapping to take element type of an arraytype
1633 */
1634 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1635 public Type apply(Type t) { return elemtype(t); }
1636 };
1638 /**
1639 * The number of dimensions of an array type.
1640 */
1641 public int dimensions(Type t) {
1642 int result = 0;
1643 while (t.tag == ARRAY) {
1644 result++;
1645 t = elemtype(t);
1646 }
1647 return result;
1648 }
1650 /**
1651 * Returns an ArrayType with the component type t
1652 *
1653 * @param t The component type of the ArrayType
1654 * @return the ArrayType for the given component
1655 */
1656 public ArrayType makeArrayType(Type t) {
1657 if (t.tag == VOID ||
1658 t.tag == PACKAGE) {
1659 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
1660 }
1661 return new ArrayType(t, syms.arrayClass);
1662 }
1663 // </editor-fold>
1665 // <editor-fold defaultstate="collapsed" desc="asSuper">
1666 /**
1667 * Return the (most specific) base type of t that starts with the
1668 * given symbol. If none exists, return null.
1669 *
1670 * @param t a type
1671 * @param sym a symbol
1672 */
1673 public Type asSuper(Type t, Symbol sym) {
1674 return asSuper.visit(t, sym);
1675 }
1676 // where
1677 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1679 public Type visitType(Type t, Symbol sym) {
1680 return null;
1681 }
1683 @Override
1684 public Type visitClassType(ClassType t, Symbol sym) {
1685 if (t.tsym == sym)
1686 return t;
1688 Type st = supertype(t);
1689 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1690 Type x = asSuper(st, sym);
1691 if (x != null)
1692 return x;
1693 }
1694 if ((sym.flags() & INTERFACE) != 0) {
1695 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1696 Type x = asSuper(l.head, sym);
1697 if (x != null)
1698 return x;
1699 }
1700 }
1701 return null;
1702 }
1704 @Override
1705 public Type visitArrayType(ArrayType t, Symbol sym) {
1706 return isSubtype(t, sym.type) ? sym.type : null;
1707 }
1709 @Override
1710 public Type visitTypeVar(TypeVar t, Symbol sym) {
1711 if (t.tsym == sym)
1712 return t;
1713 else
1714 return asSuper(t.bound, sym);
1715 }
1717 @Override
1718 public Type visitErrorType(ErrorType t, Symbol sym) {
1719 return t;
1720 }
1721 };
1723 /**
1724 * Return the base type of t or any of its outer types that starts
1725 * with the given symbol. If none exists, return null.
1726 *
1727 * @param t a type
1728 * @param sym a symbol
1729 */
1730 public Type asOuterSuper(Type t, Symbol sym) {
1731 switch (t.tag) {
1732 case CLASS:
1733 do {
1734 Type s = asSuper(t, sym);
1735 if (s != null) return s;
1736 t = t.getEnclosingType();
1737 } while (t.tag == CLASS);
1738 return null;
1739 case ARRAY:
1740 return isSubtype(t, sym.type) ? sym.type : null;
1741 case TYPEVAR:
1742 return asSuper(t, sym);
1743 case ERROR:
1744 return t;
1745 default:
1746 return null;
1747 }
1748 }
1750 /**
1751 * Return the base type of t or any of its enclosing types that
1752 * starts with the given symbol. If none exists, return null.
1753 *
1754 * @param t a type
1755 * @param sym a symbol
1756 */
1757 public Type asEnclosingSuper(Type t, Symbol sym) {
1758 switch (t.tag) {
1759 case CLASS:
1760 do {
1761 Type s = asSuper(t, sym);
1762 if (s != null) return s;
1763 Type outer = t.getEnclosingType();
1764 t = (outer.tag == CLASS) ? outer :
1765 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1766 Type.noType;
1767 } while (t.tag == CLASS);
1768 return null;
1769 case ARRAY:
1770 return isSubtype(t, sym.type) ? sym.type : null;
1771 case TYPEVAR:
1772 return asSuper(t, sym);
1773 case ERROR:
1774 return t;
1775 default:
1776 return null;
1777 }
1778 }
1779 // </editor-fold>
1781 // <editor-fold defaultstate="collapsed" desc="memberType">
1782 /**
1783 * The type of given symbol, seen as a member of t.
1784 *
1785 * @param t a type
1786 * @param sym a symbol
1787 */
1788 public Type memberType(Type t, Symbol sym) {
1789 return (sym.flags() & STATIC) != 0
1790 ? sym.type
1791 : memberType.visit(t, sym);
1792 }
1793 // where
1794 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1796 public Type visitType(Type t, Symbol sym) {
1797 return sym.type;
1798 }
1800 @Override
1801 public Type visitWildcardType(WildcardType t, Symbol sym) {
1802 return memberType(upperBound(t), sym);
1803 }
1805 @Override
1806 public Type visitClassType(ClassType t, Symbol sym) {
1807 Symbol owner = sym.owner;
1808 long flags = sym.flags();
1809 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1810 Type base = asOuterSuper(t, owner);
1811 //if t is an intersection type T = CT & I1 & I2 ... & In
1812 //its supertypes CT, I1, ... In might contain wildcards
1813 //so we need to go through capture conversion
1814 base = t.isCompound() ? capture(base) : base;
1815 if (base != null) {
1816 List<Type> ownerParams = owner.type.allparams();
1817 List<Type> baseParams = base.allparams();
1818 if (ownerParams.nonEmpty()) {
1819 if (baseParams.isEmpty()) {
1820 // then base is a raw type
1821 return erasure(sym.type);
1822 } else {
1823 return subst(sym.type, ownerParams, baseParams);
1824 }
1825 }
1826 }
1827 }
1828 return sym.type;
1829 }
1831 @Override
1832 public Type visitTypeVar(TypeVar t, Symbol sym) {
1833 return memberType(t.bound, sym);
1834 }
1836 @Override
1837 public Type visitErrorType(ErrorType t, Symbol sym) {
1838 return t;
1839 }
1840 };
1841 // </editor-fold>
1843 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1844 public boolean isAssignable(Type t, Type s) {
1845 return isAssignable(t, s, noWarnings);
1846 }
1848 /**
1849 * Is t assignable to s?<br>
1850 * Equivalent to subtype except for constant values and raw
1851 * types.<br>
1852 * (not defined for Method and ForAll types)
1853 */
1854 public boolean isAssignable(Type t, Type s, Warner warn) {
1855 if (t.tag == ERROR)
1856 return true;
1857 if (t.tag.isSubRangeOf(INT) && t.constValue() != null) {
1858 int value = ((Number)t.constValue()).intValue();
1859 switch (s.tag) {
1860 case BYTE:
1861 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1862 return true;
1863 break;
1864 case CHAR:
1865 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1866 return true;
1867 break;
1868 case SHORT:
1869 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1870 return true;
1871 break;
1872 case INT:
1873 return true;
1874 case CLASS:
1875 switch (unboxedType(s).tag) {
1876 case BYTE:
1877 case CHAR:
1878 case SHORT:
1879 return isAssignable(t, unboxedType(s), warn);
1880 }
1881 break;
1882 }
1883 }
1884 return isConvertible(t, s, warn);
1885 }
1886 // </editor-fold>
1888 // <editor-fold defaultstate="collapsed" desc="erasure">
1889 /**
1890 * The erasure of t {@code |t|} -- the type that results when all
1891 * type parameters in t are deleted.
1892 */
1893 public Type erasure(Type t) {
1894 return eraseNotNeeded(t)? t : erasure(t, false);
1895 }
1896 //where
1897 private boolean eraseNotNeeded(Type t) {
1898 // We don't want to erase primitive types and String type as that
1899 // operation is idempotent. Also, erasing these could result in loss
1900 // of information such as constant values attached to such types.
1901 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
1902 }
1904 private Type erasure(Type t, boolean recurse) {
1905 if (t.isPrimitive())
1906 return t; /* fast special case */
1907 else
1908 return erasure.visit(t, recurse);
1909 }
1910 // where
1911 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
1912 public Type visitType(Type t, Boolean recurse) {
1913 if (t.isPrimitive())
1914 return t; /*fast special case*/
1915 else
1916 return t.map(recurse ? erasureRecFun : erasureFun);
1917 }
1919 @Override
1920 public Type visitWildcardType(WildcardType t, Boolean recurse) {
1921 return erasure(upperBound(t), recurse);
1922 }
1924 @Override
1925 public Type visitClassType(ClassType t, Boolean recurse) {
1926 Type erased = t.tsym.erasure(Types.this);
1927 if (recurse) {
1928 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
1929 }
1930 return erased;
1931 }
1933 @Override
1934 public Type visitTypeVar(TypeVar t, Boolean recurse) {
1935 return erasure(t.bound, recurse);
1936 }
1938 @Override
1939 public Type visitErrorType(ErrorType t, Boolean recurse) {
1940 return t;
1941 }
1942 };
1944 private Mapping erasureFun = new Mapping ("erasure") {
1945 public Type apply(Type t) { return erasure(t); }
1946 };
1948 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
1949 public Type apply(Type t) { return erasureRecursive(t); }
1950 };
1952 public List<Type> erasure(List<Type> ts) {
1953 return Type.map(ts, erasureFun);
1954 }
1956 public Type erasureRecursive(Type t) {
1957 return erasure(t, true);
1958 }
1960 public List<Type> erasureRecursive(List<Type> ts) {
1961 return Type.map(ts, erasureRecFun);
1962 }
1963 // </editor-fold>
1965 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
1966 /**
1967 * Make a compound type from non-empty list of types
1968 *
1969 * @param bounds the types from which the compound type is formed
1970 * @param supertype is objectType if all bounds are interfaces,
1971 * null otherwise.
1972 */
1973 public Type makeCompoundType(List<Type> bounds,
1974 Type supertype) {
1975 ClassSymbol bc =
1976 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
1977 Type.moreInfo
1978 ? names.fromString(bounds.toString())
1979 : names.empty,
1980 syms.noSymbol);
1981 if (bounds.head.tag == TYPEVAR)
1982 // error condition, recover
1983 bc.erasure_field = syms.objectType;
1984 else
1985 bc.erasure_field = erasure(bounds.head);
1986 bc.members_field = new Scope(bc);
1987 ClassType bt = (ClassType)bc.type;
1988 bt.allparams_field = List.nil();
1989 if (supertype != null) {
1990 bt.supertype_field = supertype;
1991 bt.interfaces_field = bounds;
1992 } else {
1993 bt.supertype_field = bounds.head;
1994 bt.interfaces_field = bounds.tail;
1995 }
1996 Assert.check(bt.supertype_field.tsym.completer != null
1997 || !bt.supertype_field.isInterface(),
1998 bt.supertype_field);
1999 return bt;
2000 }
2002 /**
2003 * Same as {@link #makeCompoundType(List,Type)}, except that the
2004 * second parameter is computed directly. Note that this might
2005 * cause a symbol completion. Hence, this version of
2006 * makeCompoundType may not be called during a classfile read.
2007 */
2008 public Type makeCompoundType(List<Type> bounds) {
2009 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
2010 supertype(bounds.head) : null;
2011 return makeCompoundType(bounds, supertype);
2012 }
2014 /**
2015 * A convenience wrapper for {@link #makeCompoundType(List)}; the
2016 * arguments are converted to a list and passed to the other
2017 * method. Note that this might cause a symbol completion.
2018 * Hence, this version of makeCompoundType may not be called
2019 * during a classfile read.
2020 */
2021 public Type makeCompoundType(Type bound1, Type bound2) {
2022 return makeCompoundType(List.of(bound1, bound2));
2023 }
2024 // </editor-fold>
2026 // <editor-fold defaultstate="collapsed" desc="supertype">
2027 public Type supertype(Type t) {
2028 return supertype.visit(t);
2029 }
2030 // where
2031 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
2033 public Type visitType(Type t, Void ignored) {
2034 // A note on wildcards: there is no good way to
2035 // determine a supertype for a super bounded wildcard.
2036 return null;
2037 }
2039 @Override
2040 public Type visitClassType(ClassType t, Void ignored) {
2041 if (t.supertype_field == null) {
2042 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
2043 // An interface has no superclass; its supertype is Object.
2044 if (t.isInterface())
2045 supertype = ((ClassType)t.tsym.type).supertype_field;
2046 if (t.supertype_field == null) {
2047 List<Type> actuals = classBound(t).allparams();
2048 List<Type> formals = t.tsym.type.allparams();
2049 if (t.hasErasedSupertypes()) {
2050 t.supertype_field = erasureRecursive(supertype);
2051 } else if (formals.nonEmpty()) {
2052 t.supertype_field = subst(supertype, formals, actuals);
2053 }
2054 else {
2055 t.supertype_field = supertype;
2056 }
2057 }
2058 }
2059 return t.supertype_field;
2060 }
2062 /**
2063 * The supertype is always a class type. If the type
2064 * variable's bounds start with a class type, this is also
2065 * the supertype. Otherwise, the supertype is
2066 * java.lang.Object.
2067 */
2068 @Override
2069 public Type visitTypeVar(TypeVar t, Void ignored) {
2070 if (t.bound.tag == TYPEVAR ||
2071 (!t.bound.isCompound() && !t.bound.isInterface())) {
2072 return t.bound;
2073 } else {
2074 return supertype(t.bound);
2075 }
2076 }
2078 @Override
2079 public Type visitArrayType(ArrayType t, Void ignored) {
2080 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
2081 return arraySuperType();
2082 else
2083 return new ArrayType(supertype(t.elemtype), t.tsym);
2084 }
2086 @Override
2087 public Type visitErrorType(ErrorType t, Void ignored) {
2088 return t;
2089 }
2090 };
2091 // </editor-fold>
2093 // <editor-fold defaultstate="collapsed" desc="interfaces">
2094 /**
2095 * Return the interfaces implemented by this class.
2096 */
2097 public List<Type> interfaces(Type t) {
2098 return interfaces.visit(t);
2099 }
2100 // where
2101 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
2103 public List<Type> visitType(Type t, Void ignored) {
2104 return List.nil();
2105 }
2107 @Override
2108 public List<Type> visitClassType(ClassType t, Void ignored) {
2109 if (t.interfaces_field == null) {
2110 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
2111 if (t.interfaces_field == null) {
2112 // If t.interfaces_field is null, then t must
2113 // be a parameterized type (not to be confused
2114 // with a generic type declaration).
2115 // Terminology:
2116 // Parameterized type: List<String>
2117 // Generic type declaration: class List<E> { ... }
2118 // So t corresponds to List<String> and
2119 // t.tsym.type corresponds to List<E>.
2120 // The reason t must be parameterized type is
2121 // that completion will happen as a side
2122 // effect of calling
2123 // ClassSymbol.getInterfaces. Since
2124 // t.interfaces_field is null after
2125 // completion, we can assume that t is not the
2126 // type of a class/interface declaration.
2127 Assert.check(t != t.tsym.type, t);
2128 List<Type> actuals = t.allparams();
2129 List<Type> formals = t.tsym.type.allparams();
2130 if (t.hasErasedSupertypes()) {
2131 t.interfaces_field = erasureRecursive(interfaces);
2132 } else if (formals.nonEmpty()) {
2133 t.interfaces_field =
2134 upperBounds(subst(interfaces, formals, actuals));
2135 }
2136 else {
2137 t.interfaces_field = interfaces;
2138 }
2139 }
2140 }
2141 return t.interfaces_field;
2142 }
2144 @Override
2145 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
2146 if (t.bound.isCompound())
2147 return interfaces(t.bound);
2149 if (t.bound.isInterface())
2150 return List.of(t.bound);
2152 return List.nil();
2153 }
2154 };
2156 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
2157 for (Type i2 : interfaces(origin.type)) {
2158 if (isym == i2.tsym) return true;
2159 }
2160 return false;
2161 }
2162 // </editor-fold>
2164 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
2165 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
2167 public boolean isDerivedRaw(Type t) {
2168 Boolean result = isDerivedRawCache.get(t);
2169 if (result == null) {
2170 result = isDerivedRawInternal(t);
2171 isDerivedRawCache.put(t, result);
2172 }
2173 return result;
2174 }
2176 public boolean isDerivedRawInternal(Type t) {
2177 if (t.isErroneous())
2178 return false;
2179 return
2180 t.isRaw() ||
2181 supertype(t) != null && isDerivedRaw(supertype(t)) ||
2182 isDerivedRaw(interfaces(t));
2183 }
2185 public boolean isDerivedRaw(List<Type> ts) {
2186 List<Type> l = ts;
2187 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
2188 return l.nonEmpty();
2189 }
2190 // </editor-fold>
2192 // <editor-fold defaultstate="collapsed" desc="setBounds">
2193 /**
2194 * Set the bounds field of the given type variable to reflect a
2195 * (possibly multiple) list of bounds.
2196 * @param t a type variable
2197 * @param bounds the bounds, must be nonempty
2198 * @param supertype is objectType if all bounds are interfaces,
2199 * null otherwise.
2200 */
2201 public void setBounds(TypeVar t, List<Type> bounds, Type supertype) {
2202 if (bounds.tail.isEmpty())
2203 t.bound = bounds.head;
2204 else
2205 t.bound = makeCompoundType(bounds, supertype);
2206 t.rank_field = -1;
2207 }
2209 /**
2210 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
2211 * third parameter is computed directly, as follows: if all
2212 * all bounds are interface types, the computed supertype is Object,
2213 * otherwise the supertype is simply left null (in this case, the supertype
2214 * is assumed to be the head of the bound list passed as second argument).
2215 * Note that this check might cause a symbol completion. Hence, this version of
2216 * setBounds may not be called during a classfile read.
2217 */
2218 public void setBounds(TypeVar t, List<Type> bounds) {
2219 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
2220 syms.objectType : null;
2221 setBounds(t, bounds, supertype);
2222 t.rank_field = -1;
2223 }
2224 // </editor-fold>
2226 // <editor-fold defaultstate="collapsed" desc="getBounds">
2227 /**
2228 * Return list of bounds of the given type variable.
2229 */
2230 public List<Type> getBounds(TypeVar t) {
2231 if (t.bound.hasTag(NONE))
2232 return List.nil();
2233 else if (t.bound.isErroneous() || !t.bound.isCompound())
2234 return List.of(t.bound);
2235 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
2236 return interfaces(t).prepend(supertype(t));
2237 else
2238 // No superclass was given in bounds.
2239 // In this case, supertype is Object, erasure is first interface.
2240 return interfaces(t);
2241 }
2242 // </editor-fold>
2244 // <editor-fold defaultstate="collapsed" desc="classBound">
2245 /**
2246 * If the given type is a (possibly selected) type variable,
2247 * return the bounding class of this type, otherwise return the
2248 * type itself.
2249 */
2250 public Type classBound(Type t) {
2251 return classBound.visit(t);
2252 }
2253 // where
2254 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
2256 public Type visitType(Type t, Void ignored) {
2257 return t;
2258 }
2260 @Override
2261 public Type visitClassType(ClassType t, Void ignored) {
2262 Type outer1 = classBound(t.getEnclosingType());
2263 if (outer1 != t.getEnclosingType())
2264 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
2265 else
2266 return t;
2267 }
2269 @Override
2270 public Type visitTypeVar(TypeVar t, Void ignored) {
2271 return classBound(supertype(t));
2272 }
2274 @Override
2275 public Type visitErrorType(ErrorType t, Void ignored) {
2276 return t;
2277 }
2278 };
2279 // </editor-fold>
2281 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
2282 /**
2283 * Returns true iff the first signature is a <em>sub
2284 * signature</em> of the other. This is <b>not</b> an equivalence
2285 * relation.
2286 *
2287 * @jls section 8.4.2.
2288 * @see #overrideEquivalent(Type t, Type s)
2289 * @param t first signature (possibly raw).
2290 * @param s second signature (could be subjected to erasure).
2291 * @return true if t is a sub signature of s.
2292 */
2293 public boolean isSubSignature(Type t, Type s) {
2294 return isSubSignature(t, s, true);
2295 }
2297 public boolean isSubSignature(Type t, Type s, boolean strict) {
2298 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2299 }
2301 /**
2302 * Returns true iff these signatures are related by <em>override
2303 * equivalence</em>. This is the natural extension of
2304 * isSubSignature to an equivalence relation.
2305 *
2306 * @jls section 8.4.2.
2307 * @see #isSubSignature(Type t, Type s)
2308 * @param t a signature (possible raw, could be subjected to
2309 * erasure).
2310 * @param s a signature (possible raw, could be subjected to
2311 * erasure).
2312 * @return true if either argument is a sub signature of the other.
2313 */
2314 public boolean overrideEquivalent(Type t, Type s) {
2315 return hasSameArgs(t, s) ||
2316 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2317 }
2319 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
2320 for (Scope.Entry e = syms.objectType.tsym.members().lookup(msym.name) ; e.scope != null ; e = e.next()) {
2321 if (msym.overrides(e.sym, origin, Types.this, true)) {
2322 return true;
2323 }
2324 }
2325 return false;
2326 }
2328 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2329 class ImplementationCache {
2331 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
2332 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
2334 class Entry {
2335 final MethodSymbol cachedImpl;
2336 final Filter<Symbol> implFilter;
2337 final boolean checkResult;
2338 final int prevMark;
2340 public Entry(MethodSymbol cachedImpl,
2341 Filter<Symbol> scopeFilter,
2342 boolean checkResult,
2343 int prevMark) {
2344 this.cachedImpl = cachedImpl;
2345 this.implFilter = scopeFilter;
2346 this.checkResult = checkResult;
2347 this.prevMark = prevMark;
2348 }
2350 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
2351 return this.implFilter == scopeFilter &&
2352 this.checkResult == checkResult &&
2353 this.prevMark == mark;
2354 }
2355 }
2357 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2358 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2359 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2360 if (cache == null) {
2361 cache = new HashMap<TypeSymbol, Entry>();
2362 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2363 }
2364 Entry e = cache.get(origin);
2365 CompoundScope members = membersClosure(origin.type, true);
2366 if (e == null ||
2367 !e.matches(implFilter, checkResult, members.getMark())) {
2368 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2369 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2370 return impl;
2371 }
2372 else {
2373 return e.cachedImpl;
2374 }
2375 }
2377 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2378 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = supertype(t)) {
2379 while (t.tag == TYPEVAR)
2380 t = t.getUpperBound();
2381 TypeSymbol c = t.tsym;
2382 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2383 e.scope != null;
2384 e = e.next(implFilter)) {
2385 if (e.sym != null &&
2386 e.sym.overrides(ms, origin, Types.this, checkResult))
2387 return (MethodSymbol)e.sym;
2388 }
2389 }
2390 return null;
2391 }
2392 }
2394 private ImplementationCache implCache = new ImplementationCache();
2396 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2397 return implCache.get(ms, origin, checkResult, implFilter);
2398 }
2399 // </editor-fold>
2401 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2402 class MembersClosureCache extends SimpleVisitor<CompoundScope, Boolean> {
2404 private WeakHashMap<TypeSymbol, Entry> _map =
2405 new WeakHashMap<TypeSymbol, Entry>();
2407 class Entry {
2408 final boolean skipInterfaces;
2409 final CompoundScope compoundScope;
2411 public Entry(boolean skipInterfaces, CompoundScope compoundScope) {
2412 this.skipInterfaces = skipInterfaces;
2413 this.compoundScope = compoundScope;
2414 }
2416 boolean matches(boolean skipInterfaces) {
2417 return this.skipInterfaces == skipInterfaces;
2418 }
2419 }
2421 List<TypeSymbol> seenTypes = List.nil();
2423 /** members closure visitor methods **/
2425 public CompoundScope visitType(Type t, Boolean skipInterface) {
2426 return null;
2427 }
2429 @Override
2430 public CompoundScope visitClassType(ClassType t, Boolean skipInterface) {
2431 if (seenTypes.contains(t.tsym)) {
2432 //this is possible when an interface is implemented in multiple
2433 //superclasses, or when a classs hierarchy is circular - in such
2434 //cases we don't need to recurse (empty scope is returned)
2435 return new CompoundScope(t.tsym);
2436 }
2437 try {
2438 seenTypes = seenTypes.prepend(t.tsym);
2439 ClassSymbol csym = (ClassSymbol)t.tsym;
2440 Entry e = _map.get(csym);
2441 if (e == null || !e.matches(skipInterface)) {
2442 CompoundScope membersClosure = new CompoundScope(csym);
2443 if (!skipInterface) {
2444 for (Type i : interfaces(t)) {
2445 membersClosure.addSubScope(visit(i, skipInterface));
2446 }
2447 }
2448 membersClosure.addSubScope(visit(supertype(t), skipInterface));
2449 membersClosure.addSubScope(csym.members());
2450 e = new Entry(skipInterface, membersClosure);
2451 _map.put(csym, e);
2452 }
2453 return e.compoundScope;
2454 }
2455 finally {
2456 seenTypes = seenTypes.tail;
2457 }
2458 }
2460 @Override
2461 public CompoundScope visitTypeVar(TypeVar t, Boolean skipInterface) {
2462 return visit(t.getUpperBound(), skipInterface);
2463 }
2464 }
2466 private MembersClosureCache membersCache = new MembersClosureCache();
2468 public CompoundScope membersClosure(Type site, boolean skipInterface) {
2469 return membersCache.visit(site, skipInterface);
2470 }
2471 // </editor-fold>
2474 //where
2475 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
2476 Filter<Symbol> filter = new MethodFilter(ms, site);
2477 List<MethodSymbol> candidates = List.nil();
2478 for (Symbol s : membersClosure(site, false).getElements(filter)) {
2479 if (!site.tsym.isInterface() && !s.owner.isInterface()) {
2480 return List.of((MethodSymbol)s);
2481 } else if (!candidates.contains(s)) {
2482 candidates = candidates.prepend((MethodSymbol)s);
2483 }
2484 }
2485 return prune(candidates, ownerComparator);
2486 }
2488 public List<MethodSymbol> prune(List<MethodSymbol> methods, Comparator<MethodSymbol> cmp) {
2489 ListBuffer<MethodSymbol> methodsMin = ListBuffer.lb();
2490 for (MethodSymbol m1 : methods) {
2491 boolean isMin_m1 = true;
2492 for (MethodSymbol m2 : methods) {
2493 if (m1 == m2) continue;
2494 if (cmp.compare(m2, m1) < 0) {
2495 isMin_m1 = false;
2496 break;
2497 }
2498 }
2499 if (isMin_m1)
2500 methodsMin.append(m1);
2501 }
2502 return methodsMin.toList();
2503 }
2505 Comparator<MethodSymbol> ownerComparator = new Comparator<MethodSymbol>() {
2506 public int compare(MethodSymbol s1, MethodSymbol s2) {
2507 return s1.owner.isSubClass(s2.owner, Types.this) ? -1 : 1;
2508 }
2509 };
2510 // where
2511 private class MethodFilter implements Filter<Symbol> {
2513 Symbol msym;
2514 Type site;
2516 MethodFilter(Symbol msym, Type site) {
2517 this.msym = msym;
2518 this.site = site;
2519 }
2521 public boolean accepts(Symbol s) {
2522 return s.kind == Kinds.MTH &&
2523 s.name == msym.name &&
2524 s.isInheritedIn(site.tsym, Types.this) &&
2525 overrideEquivalent(memberType(site, s), memberType(site, msym));
2526 }
2527 };
2528 // </editor-fold>
2530 /**
2531 * Does t have the same arguments as s? It is assumed that both
2532 * types are (possibly polymorphic) method types. Monomorphic
2533 * method types "have the same arguments", if their argument lists
2534 * are equal. Polymorphic method types "have the same arguments",
2535 * if they have the same arguments after renaming all type
2536 * variables of one to corresponding type variables in the other,
2537 * where correspondence is by position in the type parameter list.
2538 */
2539 public boolean hasSameArgs(Type t, Type s) {
2540 return hasSameArgs(t, s, true);
2541 }
2543 public boolean hasSameArgs(Type t, Type s, boolean strict) {
2544 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
2545 }
2547 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
2548 return hasSameArgs.visit(t, s);
2549 }
2550 // where
2551 private class HasSameArgs extends TypeRelation {
2553 boolean strict;
2555 public HasSameArgs(boolean strict) {
2556 this.strict = strict;
2557 }
2559 public Boolean visitType(Type t, Type s) {
2560 throw new AssertionError();
2561 }
2563 @Override
2564 public Boolean visitMethodType(MethodType t, Type s) {
2565 return s.tag == METHOD
2566 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2567 }
2569 @Override
2570 public Boolean visitForAll(ForAll t, Type s) {
2571 if (s.tag != FORALL)
2572 return strict ? false : visitMethodType(t.asMethodType(), s);
2574 ForAll forAll = (ForAll)s;
2575 return hasSameBounds(t, forAll)
2576 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2577 }
2579 @Override
2580 public Boolean visitErrorType(ErrorType t, Type s) {
2581 return false;
2582 }
2583 };
2585 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
2586 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
2588 // </editor-fold>
2590 // <editor-fold defaultstate="collapsed" desc="subst">
2591 public List<Type> subst(List<Type> ts,
2592 List<Type> from,
2593 List<Type> to) {
2594 return new Subst(from, to).subst(ts);
2595 }
2597 /**
2598 * Substitute all occurrences of a type in `from' with the
2599 * corresponding type in `to' in 't'. Match lists `from' and `to'
2600 * from the right: If lists have different length, discard leading
2601 * elements of the longer list.
2602 */
2603 public Type subst(Type t, List<Type> from, List<Type> to) {
2604 return new Subst(from, to).subst(t);
2605 }
2607 private class Subst extends UnaryVisitor<Type> {
2608 List<Type> from;
2609 List<Type> to;
2611 public Subst(List<Type> from, List<Type> to) {
2612 int fromLength = from.length();
2613 int toLength = to.length();
2614 while (fromLength > toLength) {
2615 fromLength--;
2616 from = from.tail;
2617 }
2618 while (fromLength < toLength) {
2619 toLength--;
2620 to = to.tail;
2621 }
2622 this.from = from;
2623 this.to = to;
2624 }
2626 Type subst(Type t) {
2627 if (from.tail == null)
2628 return t;
2629 else
2630 return visit(t);
2631 }
2633 List<Type> subst(List<Type> ts) {
2634 if (from.tail == null)
2635 return ts;
2636 boolean wild = false;
2637 if (ts.nonEmpty() && from.nonEmpty()) {
2638 Type head1 = subst(ts.head);
2639 List<Type> tail1 = subst(ts.tail);
2640 if (head1 != ts.head || tail1 != ts.tail)
2641 return tail1.prepend(head1);
2642 }
2643 return ts;
2644 }
2646 public Type visitType(Type t, Void ignored) {
2647 return t;
2648 }
2650 @Override
2651 public Type visitMethodType(MethodType t, Void ignored) {
2652 List<Type> argtypes = subst(t.argtypes);
2653 Type restype = subst(t.restype);
2654 List<Type> thrown = subst(t.thrown);
2655 if (argtypes == t.argtypes &&
2656 restype == t.restype &&
2657 thrown == t.thrown)
2658 return t;
2659 else
2660 return new MethodType(argtypes, restype, thrown, t.tsym);
2661 }
2663 @Override
2664 public Type visitTypeVar(TypeVar t, Void ignored) {
2665 for (List<Type> from = this.from, to = this.to;
2666 from.nonEmpty();
2667 from = from.tail, to = to.tail) {
2668 if (t == from.head) {
2669 return to.head.withTypeVar(t);
2670 }
2671 }
2672 return t;
2673 }
2675 @Override
2676 public Type visitClassType(ClassType t, Void ignored) {
2677 if (!t.isCompound()) {
2678 List<Type> typarams = t.getTypeArguments();
2679 List<Type> typarams1 = subst(typarams);
2680 Type outer = t.getEnclosingType();
2681 Type outer1 = subst(outer);
2682 if (typarams1 == typarams && outer1 == outer)
2683 return t;
2684 else
2685 return new ClassType(outer1, typarams1, t.tsym);
2686 } else {
2687 Type st = subst(supertype(t));
2688 List<Type> is = upperBounds(subst(interfaces(t)));
2689 if (st == supertype(t) && is == interfaces(t))
2690 return t;
2691 else
2692 return makeCompoundType(is.prepend(st));
2693 }
2694 }
2696 @Override
2697 public Type visitWildcardType(WildcardType t, Void ignored) {
2698 Type bound = t.type;
2699 if (t.kind != BoundKind.UNBOUND)
2700 bound = subst(bound);
2701 if (bound == t.type) {
2702 return t;
2703 } else {
2704 if (t.isExtendsBound() && bound.isExtendsBound())
2705 bound = upperBound(bound);
2706 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2707 }
2708 }
2710 @Override
2711 public Type visitArrayType(ArrayType t, Void ignored) {
2712 Type elemtype = subst(t.elemtype);
2713 if (elemtype == t.elemtype)
2714 return t;
2715 else
2716 return new ArrayType(upperBound(elemtype), t.tsym);
2717 }
2719 @Override
2720 public Type visitForAll(ForAll t, Void ignored) {
2721 if (Type.containsAny(to, t.tvars)) {
2722 //perform alpha-renaming of free-variables in 't'
2723 //if 'to' types contain variables that are free in 't'
2724 List<Type> freevars = newInstances(t.tvars);
2725 t = new ForAll(freevars,
2726 Types.this.subst(t.qtype, t.tvars, freevars));
2727 }
2728 List<Type> tvars1 = substBounds(t.tvars, from, to);
2729 Type qtype1 = subst(t.qtype);
2730 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2731 return t;
2732 } else if (tvars1 == t.tvars) {
2733 return new ForAll(tvars1, qtype1);
2734 } else {
2735 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2736 }
2737 }
2739 @Override
2740 public Type visitErrorType(ErrorType t, Void ignored) {
2741 return t;
2742 }
2743 }
2745 public List<Type> substBounds(List<Type> tvars,
2746 List<Type> from,
2747 List<Type> to) {
2748 if (tvars.isEmpty())
2749 return tvars;
2750 ListBuffer<Type> newBoundsBuf = lb();
2751 boolean changed = false;
2752 // calculate new bounds
2753 for (Type t : tvars) {
2754 TypeVar tv = (TypeVar) t;
2755 Type bound = subst(tv.bound, from, to);
2756 if (bound != tv.bound)
2757 changed = true;
2758 newBoundsBuf.append(bound);
2759 }
2760 if (!changed)
2761 return tvars;
2762 ListBuffer<Type> newTvars = lb();
2763 // create new type variables without bounds
2764 for (Type t : tvars) {
2765 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2766 }
2767 // the new bounds should use the new type variables in place
2768 // of the old
2769 List<Type> newBounds = newBoundsBuf.toList();
2770 from = tvars;
2771 to = newTvars.toList();
2772 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2773 newBounds.head = subst(newBounds.head, from, to);
2774 }
2775 newBounds = newBoundsBuf.toList();
2776 // set the bounds of new type variables to the new bounds
2777 for (Type t : newTvars.toList()) {
2778 TypeVar tv = (TypeVar) t;
2779 tv.bound = newBounds.head;
2780 newBounds = newBounds.tail;
2781 }
2782 return newTvars.toList();
2783 }
2785 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2786 Type bound1 = subst(t.bound, from, to);
2787 if (bound1 == t.bound)
2788 return t;
2789 else {
2790 // create new type variable without bounds
2791 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2792 // the new bound should use the new type variable in place
2793 // of the old
2794 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2795 return tv;
2796 }
2797 }
2798 // </editor-fold>
2800 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2801 /**
2802 * Does t have the same bounds for quantified variables as s?
2803 */
2804 boolean hasSameBounds(ForAll t, ForAll s) {
2805 List<Type> l1 = t.tvars;
2806 List<Type> l2 = s.tvars;
2807 while (l1.nonEmpty() && l2.nonEmpty() &&
2808 isSameType(l1.head.getUpperBound(),
2809 subst(l2.head.getUpperBound(),
2810 s.tvars,
2811 t.tvars))) {
2812 l1 = l1.tail;
2813 l2 = l2.tail;
2814 }
2815 return l1.isEmpty() && l2.isEmpty();
2816 }
2817 // </editor-fold>
2819 // <editor-fold defaultstate="collapsed" desc="newInstances">
2820 /** Create new vector of type variables from list of variables
2821 * changing all recursive bounds from old to new list.
2822 */
2823 public List<Type> newInstances(List<Type> tvars) {
2824 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2825 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2826 TypeVar tv = (TypeVar) l.head;
2827 tv.bound = subst(tv.bound, tvars, tvars1);
2828 }
2829 return tvars1;
2830 }
2831 static private Mapping newInstanceFun = new Mapping("newInstanceFun") {
2832 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2833 };
2834 // </editor-fold>
2836 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
2837 return original.accept(methodWithParameters, newParams);
2838 }
2839 // where
2840 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
2841 public Type visitType(Type t, List<Type> newParams) {
2842 throw new IllegalArgumentException("Not a method type: " + t);
2843 }
2844 public Type visitMethodType(MethodType t, List<Type> newParams) {
2845 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
2846 }
2847 public Type visitForAll(ForAll t, List<Type> newParams) {
2848 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
2849 }
2850 };
2852 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
2853 return original.accept(methodWithThrown, newThrown);
2854 }
2855 // where
2856 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
2857 public Type visitType(Type t, List<Type> newThrown) {
2858 throw new IllegalArgumentException("Not a method type: " + t);
2859 }
2860 public Type visitMethodType(MethodType t, List<Type> newThrown) {
2861 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
2862 }
2863 public Type visitForAll(ForAll t, List<Type> newThrown) {
2864 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
2865 }
2866 };
2868 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
2869 return original.accept(methodWithReturn, newReturn);
2870 }
2871 // where
2872 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
2873 public Type visitType(Type t, Type newReturn) {
2874 throw new IllegalArgumentException("Not a method type: " + t);
2875 }
2876 public Type visitMethodType(MethodType t, Type newReturn) {
2877 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym);
2878 }
2879 public Type visitForAll(ForAll t, Type newReturn) {
2880 return new ForAll(t.tvars, t.qtype.accept(this, newReturn));
2881 }
2882 };
2884 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2885 public Type createErrorType(Type originalType) {
2886 return new ErrorType(originalType, syms.errSymbol);
2887 }
2889 public Type createErrorType(ClassSymbol c, Type originalType) {
2890 return new ErrorType(c, originalType);
2891 }
2893 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
2894 return new ErrorType(name, container, originalType);
2895 }
2896 // </editor-fold>
2898 // <editor-fold defaultstate="collapsed" desc="rank">
2899 /**
2900 * The rank of a class is the length of the longest path between
2901 * the class and java.lang.Object in the class inheritance
2902 * graph. Undefined for all but reference types.
2903 */
2904 public int rank(Type t) {
2905 switch(t.tag) {
2906 case CLASS: {
2907 ClassType cls = (ClassType)t;
2908 if (cls.rank_field < 0) {
2909 Name fullname = cls.tsym.getQualifiedName();
2910 if (fullname == names.java_lang_Object)
2911 cls.rank_field = 0;
2912 else {
2913 int r = rank(supertype(cls));
2914 for (List<Type> l = interfaces(cls);
2915 l.nonEmpty();
2916 l = l.tail) {
2917 if (rank(l.head) > r)
2918 r = rank(l.head);
2919 }
2920 cls.rank_field = r + 1;
2921 }
2922 }
2923 return cls.rank_field;
2924 }
2925 case TYPEVAR: {
2926 TypeVar tvar = (TypeVar)t;
2927 if (tvar.rank_field < 0) {
2928 int r = rank(supertype(tvar));
2929 for (List<Type> l = interfaces(tvar);
2930 l.nonEmpty();
2931 l = l.tail) {
2932 if (rank(l.head) > r) r = rank(l.head);
2933 }
2934 tvar.rank_field = r + 1;
2935 }
2936 return tvar.rank_field;
2937 }
2938 case ERROR:
2939 return 0;
2940 default:
2941 throw new AssertionError();
2942 }
2943 }
2944 // </editor-fold>
2946 /**
2947 * Helper method for generating a string representation of a given type
2948 * accordingly to a given locale
2949 */
2950 public String toString(Type t, Locale locale) {
2951 return Printer.createStandardPrinter(messages).visit(t, locale);
2952 }
2954 /**
2955 * Helper method for generating a string representation of a given type
2956 * accordingly to a given locale
2957 */
2958 public String toString(Symbol t, Locale locale) {
2959 return Printer.createStandardPrinter(messages).visit(t, locale);
2960 }
2962 // <editor-fold defaultstate="collapsed" desc="toString">
2963 /**
2964 * This toString is slightly more descriptive than the one on Type.
2965 *
2966 * @deprecated Types.toString(Type t, Locale l) provides better support
2967 * for localization
2968 */
2969 @Deprecated
2970 public String toString(Type t) {
2971 if (t.tag == FORALL) {
2972 ForAll forAll = (ForAll)t;
2973 return typaramsString(forAll.tvars) + forAll.qtype;
2974 }
2975 return "" + t;
2976 }
2977 // where
2978 private String typaramsString(List<Type> tvars) {
2979 StringBuilder s = new StringBuilder();
2980 s.append('<');
2981 boolean first = true;
2982 for (Type t : tvars) {
2983 if (!first) s.append(", ");
2984 first = false;
2985 appendTyparamString(((TypeVar)t), s);
2986 }
2987 s.append('>');
2988 return s.toString();
2989 }
2990 private void appendTyparamString(TypeVar t, StringBuilder buf) {
2991 buf.append(t);
2992 if (t.bound == null ||
2993 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
2994 return;
2995 buf.append(" extends "); // Java syntax; no need for i18n
2996 Type bound = t.bound;
2997 if (!bound.isCompound()) {
2998 buf.append(bound);
2999 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
3000 buf.append(supertype(t));
3001 for (Type intf : interfaces(t)) {
3002 buf.append('&');
3003 buf.append(intf);
3004 }
3005 } else {
3006 // No superclass was given in bounds.
3007 // In this case, supertype is Object, erasure is first interface.
3008 boolean first = true;
3009 for (Type intf : interfaces(t)) {
3010 if (!first) buf.append('&');
3011 first = false;
3012 buf.append(intf);
3013 }
3014 }
3015 }
3016 // </editor-fold>
3018 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
3019 /**
3020 * A cache for closures.
3021 *
3022 * <p>A closure is a list of all the supertypes and interfaces of
3023 * a class or interface type, ordered by ClassSymbol.precedes
3024 * (that is, subclasses come first, arbitrary but fixed
3025 * otherwise).
3026 */
3027 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
3029 /**
3030 * Returns the closure of a class or interface type.
3031 */
3032 public List<Type> closure(Type t) {
3033 List<Type> cl = closureCache.get(t);
3034 if (cl == null) {
3035 Type st = supertype(t);
3036 if (!t.isCompound()) {
3037 if (st.tag == CLASS) {
3038 cl = insert(closure(st), t);
3039 } else if (st.tag == TYPEVAR) {
3040 cl = closure(st).prepend(t);
3041 } else {
3042 cl = List.of(t);
3043 }
3044 } else {
3045 cl = closure(supertype(t));
3046 }
3047 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
3048 cl = union(cl, closure(l.head));
3049 closureCache.put(t, cl);
3050 }
3051 return cl;
3052 }
3054 /**
3055 * Insert a type in a closure
3056 */
3057 public List<Type> insert(List<Type> cl, Type t) {
3058 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
3059 return cl.prepend(t);
3060 } else if (cl.head.tsym.precedes(t.tsym, this)) {
3061 return insert(cl.tail, t).prepend(cl.head);
3062 } else {
3063 return cl;
3064 }
3065 }
3067 /**
3068 * Form the union of two closures
3069 */
3070 public List<Type> union(List<Type> cl1, List<Type> cl2) {
3071 if (cl1.isEmpty()) {
3072 return cl2;
3073 } else if (cl2.isEmpty()) {
3074 return cl1;
3075 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
3076 return union(cl1.tail, cl2).prepend(cl1.head);
3077 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
3078 return union(cl1, cl2.tail).prepend(cl2.head);
3079 } else {
3080 return union(cl1.tail, cl2.tail).prepend(cl1.head);
3081 }
3082 }
3084 /**
3085 * Intersect two closures
3086 */
3087 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
3088 if (cl1 == cl2)
3089 return cl1;
3090 if (cl1.isEmpty() || cl2.isEmpty())
3091 return List.nil();
3092 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
3093 return intersect(cl1.tail, cl2);
3094 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
3095 return intersect(cl1, cl2.tail);
3096 if (isSameType(cl1.head, cl2.head))
3097 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
3098 if (cl1.head.tsym == cl2.head.tsym &&
3099 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
3100 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
3101 Type merge = merge(cl1.head,cl2.head);
3102 return intersect(cl1.tail, cl2.tail).prepend(merge);
3103 }
3104 if (cl1.head.isRaw() || cl2.head.isRaw())
3105 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
3106 }
3107 return intersect(cl1.tail, cl2.tail);
3108 }
3109 // where
3110 class TypePair {
3111 final Type t1;
3112 final Type t2;
3113 TypePair(Type t1, Type t2) {
3114 this.t1 = t1;
3115 this.t2 = t2;
3116 }
3117 @Override
3118 public int hashCode() {
3119 return 127 * Types.hashCode(t1) + Types.hashCode(t2);
3120 }
3121 @Override
3122 public boolean equals(Object obj) {
3123 if (!(obj instanceof TypePair))
3124 return false;
3125 TypePair typePair = (TypePair)obj;
3126 return isSameType(t1, typePair.t1)
3127 && isSameType(t2, typePair.t2);
3128 }
3129 }
3130 Set<TypePair> mergeCache = new HashSet<TypePair>();
3131 private Type merge(Type c1, Type c2) {
3132 ClassType class1 = (ClassType) c1;
3133 List<Type> act1 = class1.getTypeArguments();
3134 ClassType class2 = (ClassType) c2;
3135 List<Type> act2 = class2.getTypeArguments();
3136 ListBuffer<Type> merged = new ListBuffer<Type>();
3137 List<Type> typarams = class1.tsym.type.getTypeArguments();
3139 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
3140 if (containsType(act1.head, act2.head)) {
3141 merged.append(act1.head);
3142 } else if (containsType(act2.head, act1.head)) {
3143 merged.append(act2.head);
3144 } else {
3145 TypePair pair = new TypePair(c1, c2);
3146 Type m;
3147 if (mergeCache.add(pair)) {
3148 m = new WildcardType(lub(upperBound(act1.head),
3149 upperBound(act2.head)),
3150 BoundKind.EXTENDS,
3151 syms.boundClass);
3152 mergeCache.remove(pair);
3153 } else {
3154 m = new WildcardType(syms.objectType,
3155 BoundKind.UNBOUND,
3156 syms.boundClass);
3157 }
3158 merged.append(m.withTypeVar(typarams.head));
3159 }
3160 act1 = act1.tail;
3161 act2 = act2.tail;
3162 typarams = typarams.tail;
3163 }
3164 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
3165 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
3166 }
3168 /**
3169 * Return the minimum type of a closure, a compound type if no
3170 * unique minimum exists.
3171 */
3172 private Type compoundMin(List<Type> cl) {
3173 if (cl.isEmpty()) return syms.objectType;
3174 List<Type> compound = closureMin(cl);
3175 if (compound.isEmpty())
3176 return null;
3177 else if (compound.tail.isEmpty())
3178 return compound.head;
3179 else
3180 return makeCompoundType(compound);
3181 }
3183 /**
3184 * Return the minimum types of a closure, suitable for computing
3185 * compoundMin or glb.
3186 */
3187 private List<Type> closureMin(List<Type> cl) {
3188 ListBuffer<Type> classes = lb();
3189 ListBuffer<Type> interfaces = lb();
3190 while (!cl.isEmpty()) {
3191 Type current = cl.head;
3192 if (current.isInterface())
3193 interfaces.append(current);
3194 else
3195 classes.append(current);
3196 ListBuffer<Type> candidates = lb();
3197 for (Type t : cl.tail) {
3198 if (!isSubtypeNoCapture(current, t))
3199 candidates.append(t);
3200 }
3201 cl = candidates.toList();
3202 }
3203 return classes.appendList(interfaces).toList();
3204 }
3206 /**
3207 * Return the least upper bound of pair of types. if the lub does
3208 * not exist return null.
3209 */
3210 public Type lub(Type t1, Type t2) {
3211 return lub(List.of(t1, t2));
3212 }
3214 /**
3215 * Return the least upper bound (lub) of set of types. If the lub
3216 * does not exist return the type of null (bottom).
3217 */
3218 public Type lub(List<Type> ts) {
3219 final int ARRAY_BOUND = 1;
3220 final int CLASS_BOUND = 2;
3221 int boundkind = 0;
3222 for (Type t : ts) {
3223 switch (t.tag) {
3224 case CLASS:
3225 boundkind |= CLASS_BOUND;
3226 break;
3227 case ARRAY:
3228 boundkind |= ARRAY_BOUND;
3229 break;
3230 case TYPEVAR:
3231 do {
3232 t = t.getUpperBound();
3233 } while (t.tag == TYPEVAR);
3234 if (t.tag == ARRAY) {
3235 boundkind |= ARRAY_BOUND;
3236 } else {
3237 boundkind |= CLASS_BOUND;
3238 }
3239 break;
3240 default:
3241 if (t.isPrimitive())
3242 return syms.errType;
3243 }
3244 }
3245 switch (boundkind) {
3246 case 0:
3247 return syms.botType;
3249 case ARRAY_BOUND:
3250 // calculate lub(A[], B[])
3251 List<Type> elements = Type.map(ts, elemTypeFun);
3252 for (Type t : elements) {
3253 if (t.isPrimitive()) {
3254 // if a primitive type is found, then return
3255 // arraySuperType unless all the types are the
3256 // same
3257 Type first = ts.head;
3258 for (Type s : ts.tail) {
3259 if (!isSameType(first, s)) {
3260 // lub(int[], B[]) is Cloneable & Serializable
3261 return arraySuperType();
3262 }
3263 }
3264 // all the array types are the same, return one
3265 // lub(int[], int[]) is int[]
3266 return first;
3267 }
3268 }
3269 // lub(A[], B[]) is lub(A, B)[]
3270 return new ArrayType(lub(elements), syms.arrayClass);
3272 case CLASS_BOUND:
3273 // calculate lub(A, B)
3274 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
3275 ts = ts.tail;
3276 Assert.check(!ts.isEmpty());
3277 //step 1 - compute erased candidate set (EC)
3278 List<Type> cl = erasedSupertypes(ts.head);
3279 for (Type t : ts.tail) {
3280 if (t.tag == CLASS || t.tag == TYPEVAR)
3281 cl = intersect(cl, erasedSupertypes(t));
3282 }
3283 //step 2 - compute minimal erased candidate set (MEC)
3284 List<Type> mec = closureMin(cl);
3285 //step 3 - for each element G in MEC, compute lci(Inv(G))
3286 List<Type> candidates = List.nil();
3287 for (Type erasedSupertype : mec) {
3288 List<Type> lci = List.of(asSuper(ts.head, erasedSupertype.tsym));
3289 for (Type t : ts) {
3290 lci = intersect(lci, List.of(asSuper(t, erasedSupertype.tsym)));
3291 }
3292 candidates = candidates.appendList(lci);
3293 }
3294 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
3295 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
3296 return compoundMin(candidates);
3298 default:
3299 // calculate lub(A, B[])
3300 List<Type> classes = List.of(arraySuperType());
3301 for (Type t : ts) {
3302 if (t.tag != ARRAY) // Filter out any arrays
3303 classes = classes.prepend(t);
3304 }
3305 // lub(A, B[]) is lub(A, arraySuperType)
3306 return lub(classes);
3307 }
3308 }
3309 // where
3310 List<Type> erasedSupertypes(Type t) {
3311 ListBuffer<Type> buf = lb();
3312 for (Type sup : closure(t)) {
3313 if (sup.tag == TYPEVAR) {
3314 buf.append(sup);
3315 } else {
3316 buf.append(erasure(sup));
3317 }
3318 }
3319 return buf.toList();
3320 }
3322 private Type arraySuperType = null;
3323 private Type arraySuperType() {
3324 // initialized lazily to avoid problems during compiler startup
3325 if (arraySuperType == null) {
3326 synchronized (this) {
3327 if (arraySuperType == null) {
3328 // JLS 10.8: all arrays implement Cloneable and Serializable.
3329 arraySuperType = makeCompoundType(List.of(syms.serializableType,
3330 syms.cloneableType),
3331 syms.objectType);
3332 }
3333 }
3334 }
3335 return arraySuperType;
3336 }
3337 // </editor-fold>
3339 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
3340 public Type glb(List<Type> ts) {
3341 Type t1 = ts.head;
3342 for (Type t2 : ts.tail) {
3343 if (t1.isErroneous())
3344 return t1;
3345 t1 = glb(t1, t2);
3346 }
3347 return t1;
3348 }
3349 //where
3350 public Type glb(Type t, Type s) {
3351 if (s == null)
3352 return t;
3353 else if (t.isPrimitive() || s.isPrimitive())
3354 return syms.errType;
3355 else if (isSubtypeNoCapture(t, s))
3356 return t;
3357 else if (isSubtypeNoCapture(s, t))
3358 return s;
3360 List<Type> closure = union(closure(t), closure(s));
3361 List<Type> bounds = closureMin(closure);
3363 if (bounds.isEmpty()) { // length == 0
3364 return syms.objectType;
3365 } else if (bounds.tail.isEmpty()) { // length == 1
3366 return bounds.head;
3367 } else { // length > 1
3368 int classCount = 0;
3369 for (Type bound : bounds)
3370 if (!bound.isInterface())
3371 classCount++;
3372 if (classCount > 1)
3373 return createErrorType(t);
3374 }
3375 return makeCompoundType(bounds);
3376 }
3377 // </editor-fold>
3379 // <editor-fold defaultstate="collapsed" desc="hashCode">
3380 /**
3381 * Compute a hash code on a type.
3382 */
3383 public static int hashCode(Type t) {
3384 return hashCode.visit(t);
3385 }
3386 // where
3387 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
3389 public Integer visitType(Type t, Void ignored) {
3390 return t.tag.ordinal();
3391 }
3393 @Override
3394 public Integer visitClassType(ClassType t, Void ignored) {
3395 int result = visit(t.getEnclosingType());
3396 result *= 127;
3397 result += t.tsym.flatName().hashCode();
3398 for (Type s : t.getTypeArguments()) {
3399 result *= 127;
3400 result += visit(s);
3401 }
3402 return result;
3403 }
3405 @Override
3406 public Integer visitWildcardType(WildcardType t, Void ignored) {
3407 int result = t.kind.hashCode();
3408 if (t.type != null) {
3409 result *= 127;
3410 result += visit(t.type);
3411 }
3412 return result;
3413 }
3415 @Override
3416 public Integer visitArrayType(ArrayType t, Void ignored) {
3417 return visit(t.elemtype) + 12;
3418 }
3420 @Override
3421 public Integer visitTypeVar(TypeVar t, Void ignored) {
3422 return System.identityHashCode(t.tsym);
3423 }
3425 @Override
3426 public Integer visitUndetVar(UndetVar t, Void ignored) {
3427 return System.identityHashCode(t);
3428 }
3430 @Override
3431 public Integer visitErrorType(ErrorType t, Void ignored) {
3432 return 0;
3433 }
3434 };
3435 // </editor-fold>
3437 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
3438 /**
3439 * Does t have a result that is a subtype of the result type of s,
3440 * suitable for covariant returns? It is assumed that both types
3441 * are (possibly polymorphic) method types. Monomorphic method
3442 * types are handled in the obvious way. Polymorphic method types
3443 * require renaming all type variables of one to corresponding
3444 * type variables in the other, where correspondence is by
3445 * position in the type parameter list. */
3446 public boolean resultSubtype(Type t, Type s, Warner warner) {
3447 List<Type> tvars = t.getTypeArguments();
3448 List<Type> svars = s.getTypeArguments();
3449 Type tres = t.getReturnType();
3450 Type sres = subst(s.getReturnType(), svars, tvars);
3451 return covariantReturnType(tres, sres, warner);
3452 }
3454 /**
3455 * Return-Type-Substitutable.
3456 * @jls section 8.4.5
3457 */
3458 public boolean returnTypeSubstitutable(Type r1, Type r2) {
3459 if (hasSameArgs(r1, r2))
3460 return resultSubtype(r1, r2, noWarnings);
3461 else
3462 return covariantReturnType(r1.getReturnType(),
3463 erasure(r2.getReturnType()),
3464 noWarnings);
3465 }
3467 public boolean returnTypeSubstitutable(Type r1,
3468 Type r2, Type r2res,
3469 Warner warner) {
3470 if (isSameType(r1.getReturnType(), r2res))
3471 return true;
3472 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
3473 return false;
3475 if (hasSameArgs(r1, r2))
3476 return covariantReturnType(r1.getReturnType(), r2res, warner);
3477 if (!allowCovariantReturns)
3478 return false;
3479 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
3480 return true;
3481 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
3482 return false;
3483 warner.warn(LintCategory.UNCHECKED);
3484 return true;
3485 }
3487 /**
3488 * Is t an appropriate return type in an overrider for a
3489 * method that returns s?
3490 */
3491 public boolean covariantReturnType(Type t, Type s, Warner warner) {
3492 return
3493 isSameType(t, s) ||
3494 allowCovariantReturns &&
3495 !t.isPrimitive() &&
3496 !s.isPrimitive() &&
3497 isAssignable(t, s, warner);
3498 }
3499 // </editor-fold>
3501 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
3502 /**
3503 * Return the class that boxes the given primitive.
3504 */
3505 public ClassSymbol boxedClass(Type t) {
3506 return reader.enterClass(syms.boxedName[t.tag.ordinal()]);
3507 }
3509 /**
3510 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
3511 */
3512 public Type boxedTypeOrType(Type t) {
3513 return t.isPrimitive() ?
3514 boxedClass(t).type :
3515 t;
3516 }
3518 /**
3519 * Return the primitive type corresponding to a boxed type.
3520 */
3521 public Type unboxedType(Type t) {
3522 if (allowBoxing) {
3523 for (int i=0; i<syms.boxedName.length; i++) {
3524 Name box = syms.boxedName[i];
3525 if (box != null &&
3526 asSuper(t, reader.enterClass(box)) != null)
3527 return syms.typeOfTag[i];
3528 }
3529 }
3530 return Type.noType;
3531 }
3533 /**
3534 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
3535 */
3536 public Type unboxedTypeOrType(Type t) {
3537 Type unboxedType = unboxedType(t);
3538 return unboxedType.tag == NONE ? t : unboxedType;
3539 }
3540 // </editor-fold>
3542 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3543 /*
3544 * JLS 5.1.10 Capture Conversion:
3545 *
3546 * Let G name a generic type declaration with n formal type
3547 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3548 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3549 * where, for 1 <= i <= n:
3550 *
3551 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3552 * Si is a fresh type variable whose upper bound is
3553 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3554 * type.
3555 *
3556 * + If Ti is a wildcard type argument of the form ? extends Bi,
3557 * then Si is a fresh type variable whose upper bound is
3558 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3559 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3560 * a compile-time error if for any two classes (not interfaces)
3561 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3562 *
3563 * + If Ti is a wildcard type argument of the form ? super Bi,
3564 * then Si is a fresh type variable whose upper bound is
3565 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3566 *
3567 * + Otherwise, Si = Ti.
3568 *
3569 * Capture conversion on any type other than a parameterized type
3570 * (4.5) acts as an identity conversion (5.1.1). Capture
3571 * conversions never require a special action at run time and
3572 * therefore never throw an exception at run time.
3573 *
3574 * Capture conversion is not applied recursively.
3575 */
3576 /**
3577 * Capture conversion as specified by the JLS.
3578 */
3580 public List<Type> capture(List<Type> ts) {
3581 List<Type> buf = List.nil();
3582 for (Type t : ts) {
3583 buf = buf.prepend(capture(t));
3584 }
3585 return buf.reverse();
3586 }
3587 public Type capture(Type t) {
3588 if (t.tag != CLASS)
3589 return t;
3590 if (t.getEnclosingType() != Type.noType) {
3591 Type capturedEncl = capture(t.getEnclosingType());
3592 if (capturedEncl != t.getEnclosingType()) {
3593 Type type1 = memberType(capturedEncl, t.tsym);
3594 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3595 }
3596 }
3597 ClassType cls = (ClassType)t;
3598 if (cls.isRaw() || !cls.isParameterized())
3599 return cls;
3601 ClassType G = (ClassType)cls.asElement().asType();
3602 List<Type> A = G.getTypeArguments();
3603 List<Type> T = cls.getTypeArguments();
3604 List<Type> S = freshTypeVariables(T);
3606 List<Type> currentA = A;
3607 List<Type> currentT = T;
3608 List<Type> currentS = S;
3609 boolean captured = false;
3610 while (!currentA.isEmpty() &&
3611 !currentT.isEmpty() &&
3612 !currentS.isEmpty()) {
3613 if (currentS.head != currentT.head) {
3614 captured = true;
3615 WildcardType Ti = (WildcardType)currentT.head;
3616 Type Ui = currentA.head.getUpperBound();
3617 CapturedType Si = (CapturedType)currentS.head;
3618 if (Ui == null)
3619 Ui = syms.objectType;
3620 switch (Ti.kind) {
3621 case UNBOUND:
3622 Si.bound = subst(Ui, A, S);
3623 Si.lower = syms.botType;
3624 break;
3625 case EXTENDS:
3626 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3627 Si.lower = syms.botType;
3628 break;
3629 case SUPER:
3630 Si.bound = subst(Ui, A, S);
3631 Si.lower = Ti.getSuperBound();
3632 break;
3633 }
3634 if (Si.bound == Si.lower)
3635 currentS.head = Si.bound;
3636 }
3637 currentA = currentA.tail;
3638 currentT = currentT.tail;
3639 currentS = currentS.tail;
3640 }
3641 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3642 return erasure(t); // some "rare" type involved
3644 if (captured)
3645 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3646 else
3647 return t;
3648 }
3649 // where
3650 public List<Type> freshTypeVariables(List<Type> types) {
3651 ListBuffer<Type> result = lb();
3652 for (Type t : types) {
3653 if (t.tag == WILDCARD) {
3654 Type bound = ((WildcardType)t).getExtendsBound();
3655 if (bound == null)
3656 bound = syms.objectType;
3657 result.append(new CapturedType(capturedName,
3658 syms.noSymbol,
3659 bound,
3660 syms.botType,
3661 (WildcardType)t));
3662 } else {
3663 result.append(t);
3664 }
3665 }
3666 return result.toList();
3667 }
3668 // </editor-fold>
3670 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3671 private List<Type> upperBounds(List<Type> ss) {
3672 if (ss.isEmpty()) return ss;
3673 Type head = upperBound(ss.head);
3674 List<Type> tail = upperBounds(ss.tail);
3675 if (head != ss.head || tail != ss.tail)
3676 return tail.prepend(head);
3677 else
3678 return ss;
3679 }
3681 private boolean sideCast(Type from, Type to, Warner warn) {
3682 // We are casting from type $from$ to type $to$, which are
3683 // non-final unrelated types. This method
3684 // tries to reject a cast by transferring type parameters
3685 // from $to$ to $from$ by common superinterfaces.
3686 boolean reverse = false;
3687 Type target = to;
3688 if ((to.tsym.flags() & INTERFACE) == 0) {
3689 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3690 reverse = true;
3691 to = from;
3692 from = target;
3693 }
3694 List<Type> commonSupers = superClosure(to, erasure(from));
3695 boolean giveWarning = commonSupers.isEmpty();
3696 // The arguments to the supers could be unified here to
3697 // get a more accurate analysis
3698 while (commonSupers.nonEmpty()) {
3699 Type t1 = asSuper(from, commonSupers.head.tsym);
3700 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3701 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3702 return false;
3703 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3704 commonSupers = commonSupers.tail;
3705 }
3706 if (giveWarning && !isReifiable(reverse ? from : to))
3707 warn.warn(LintCategory.UNCHECKED);
3708 if (!allowCovariantReturns)
3709 // reject if there is a common method signature with
3710 // incompatible return types.
3711 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3712 return true;
3713 }
3715 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3716 // We are casting from type $from$ to type $to$, which are
3717 // unrelated types one of which is final and the other of
3718 // which is an interface. This method
3719 // tries to reject a cast by transferring type parameters
3720 // from the final class to the interface.
3721 boolean reverse = false;
3722 Type target = to;
3723 if ((to.tsym.flags() & INTERFACE) == 0) {
3724 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3725 reverse = true;
3726 to = from;
3727 from = target;
3728 }
3729 Assert.check((from.tsym.flags() & FINAL) != 0);
3730 Type t1 = asSuper(from, to.tsym);
3731 if (t1 == null) return false;
3732 Type t2 = to;
3733 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3734 return false;
3735 if (!allowCovariantReturns)
3736 // reject if there is a common method signature with
3737 // incompatible return types.
3738 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3739 if (!isReifiable(target) &&
3740 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3741 warn.warn(LintCategory.UNCHECKED);
3742 return true;
3743 }
3745 private boolean giveWarning(Type from, Type to) {
3746 Type subFrom = asSub(from, to.tsym);
3747 return to.isParameterized() &&
3748 (!(isUnbounded(to) ||
3749 isSubtype(from, to) ||
3750 ((subFrom != null) && containsType(to.allparams(), subFrom.allparams()))));
3751 }
3753 private List<Type> superClosure(Type t, Type s) {
3754 List<Type> cl = List.nil();
3755 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3756 if (isSubtype(s, erasure(l.head))) {
3757 cl = insert(cl, l.head);
3758 } else {
3759 cl = union(cl, superClosure(l.head, s));
3760 }
3761 }
3762 return cl;
3763 }
3765 private boolean containsTypeEquivalent(Type t, Type s) {
3766 return
3767 isSameType(t, s) || // shortcut
3768 containsType(t, s) && containsType(s, t);
3769 }
3771 // <editor-fold defaultstate="collapsed" desc="adapt">
3772 /**
3773 * Adapt a type by computing a substitution which maps a source
3774 * type to a target type.
3775 *
3776 * @param source the source type
3777 * @param target the target type
3778 * @param from the type variables of the computed substitution
3779 * @param to the types of the computed substitution.
3780 */
3781 public void adapt(Type source,
3782 Type target,
3783 ListBuffer<Type> from,
3784 ListBuffer<Type> to) throws AdaptFailure {
3785 new Adapter(from, to).adapt(source, target);
3786 }
3788 class Adapter extends SimpleVisitor<Void, Type> {
3790 ListBuffer<Type> from;
3791 ListBuffer<Type> to;
3792 Map<Symbol,Type> mapping;
3794 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3795 this.from = from;
3796 this.to = to;
3797 mapping = new HashMap<Symbol,Type>();
3798 }
3800 public void adapt(Type source, Type target) throws AdaptFailure {
3801 visit(source, target);
3802 List<Type> fromList = from.toList();
3803 List<Type> toList = to.toList();
3804 while (!fromList.isEmpty()) {
3805 Type val = mapping.get(fromList.head.tsym);
3806 if (toList.head != val)
3807 toList.head = val;
3808 fromList = fromList.tail;
3809 toList = toList.tail;
3810 }
3811 }
3813 @Override
3814 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3815 if (target.tag == CLASS)
3816 adaptRecursive(source.allparams(), target.allparams());
3817 return null;
3818 }
3820 @Override
3821 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3822 if (target.tag == ARRAY)
3823 adaptRecursive(elemtype(source), elemtype(target));
3824 return null;
3825 }
3827 @Override
3828 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3829 if (source.isExtendsBound())
3830 adaptRecursive(upperBound(source), upperBound(target));
3831 else if (source.isSuperBound())
3832 adaptRecursive(lowerBound(source), lowerBound(target));
3833 return null;
3834 }
3836 @Override
3837 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3838 // Check to see if there is
3839 // already a mapping for $source$, in which case
3840 // the old mapping will be merged with the new
3841 Type val = mapping.get(source.tsym);
3842 if (val != null) {
3843 if (val.isSuperBound() && target.isSuperBound()) {
3844 val = isSubtype(lowerBound(val), lowerBound(target))
3845 ? target : val;
3846 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3847 val = isSubtype(upperBound(val), upperBound(target))
3848 ? val : target;
3849 } else if (!isSameType(val, target)) {
3850 throw new AdaptFailure();
3851 }
3852 } else {
3853 val = target;
3854 from.append(source);
3855 to.append(target);
3856 }
3857 mapping.put(source.tsym, val);
3858 return null;
3859 }
3861 @Override
3862 public Void visitType(Type source, Type target) {
3863 return null;
3864 }
3866 private Set<TypePair> cache = new HashSet<TypePair>();
3868 private void adaptRecursive(Type source, Type target) {
3869 TypePair pair = new TypePair(source, target);
3870 if (cache.add(pair)) {
3871 try {
3872 visit(source, target);
3873 } finally {
3874 cache.remove(pair);
3875 }
3876 }
3877 }
3879 private void adaptRecursive(List<Type> source, List<Type> target) {
3880 if (source.length() == target.length()) {
3881 while (source.nonEmpty()) {
3882 adaptRecursive(source.head, target.head);
3883 source = source.tail;
3884 target = target.tail;
3885 }
3886 }
3887 }
3888 }
3890 public static class AdaptFailure extends RuntimeException {
3891 static final long serialVersionUID = -7490231548272701566L;
3892 }
3894 private void adaptSelf(Type t,
3895 ListBuffer<Type> from,
3896 ListBuffer<Type> to) {
3897 try {
3898 //if (t.tsym.type != t)
3899 adapt(t.tsym.type, t, from, to);
3900 } catch (AdaptFailure ex) {
3901 // Adapt should never fail calculating a mapping from
3902 // t.tsym.type to t as there can be no merge problem.
3903 throw new AssertionError(ex);
3904 }
3905 }
3906 // </editor-fold>
3908 /**
3909 * Rewrite all type variables (universal quantifiers) in the given
3910 * type to wildcards (existential quantifiers). This is used to
3911 * determine if a cast is allowed. For example, if high is true
3912 * and {@code T <: Number}, then {@code List<T>} is rewritten to
3913 * {@code List<? extends Number>}. Since {@code List<Integer> <:
3914 * List<? extends Number>} a {@code List<T>} can be cast to {@code
3915 * List<Integer>} with a warning.
3916 * @param t a type
3917 * @param high if true return an upper bound; otherwise a lower
3918 * bound
3919 * @param rewriteTypeVars only rewrite captured wildcards if false;
3920 * otherwise rewrite all type variables
3921 * @return the type rewritten with wildcards (existential
3922 * quantifiers) only
3923 */
3924 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
3925 return new Rewriter(high, rewriteTypeVars).visit(t);
3926 }
3928 class Rewriter extends UnaryVisitor<Type> {
3930 boolean high;
3931 boolean rewriteTypeVars;
3933 Rewriter(boolean high, boolean rewriteTypeVars) {
3934 this.high = high;
3935 this.rewriteTypeVars = rewriteTypeVars;
3936 }
3938 @Override
3939 public Type visitClassType(ClassType t, Void s) {
3940 ListBuffer<Type> rewritten = new ListBuffer<Type>();
3941 boolean changed = false;
3942 for (Type arg : t.allparams()) {
3943 Type bound = visit(arg);
3944 if (arg != bound) {
3945 changed = true;
3946 }
3947 rewritten.append(bound);
3948 }
3949 if (changed)
3950 return subst(t.tsym.type,
3951 t.tsym.type.allparams(),
3952 rewritten.toList());
3953 else
3954 return t;
3955 }
3957 public Type visitType(Type t, Void s) {
3958 return high ? upperBound(t) : lowerBound(t);
3959 }
3961 @Override
3962 public Type visitCapturedType(CapturedType t, Void s) {
3963 Type w_bound = t.wildcard.type;
3964 Type bound = w_bound.contains(t) ?
3965 erasure(w_bound) :
3966 visit(w_bound);
3967 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
3968 }
3970 @Override
3971 public Type visitTypeVar(TypeVar t, Void s) {
3972 if (rewriteTypeVars) {
3973 Type bound = t.bound.contains(t) ?
3974 erasure(t.bound) :
3975 visit(t.bound);
3976 return rewriteAsWildcardType(bound, t, EXTENDS);
3977 } else {
3978 return t;
3979 }
3980 }
3982 @Override
3983 public Type visitWildcardType(WildcardType t, Void s) {
3984 Type bound2 = visit(t.type);
3985 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
3986 }
3988 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
3989 switch (bk) {
3990 case EXTENDS: return high ?
3991 makeExtendsWildcard(B(bound), formal) :
3992 makeExtendsWildcard(syms.objectType, formal);
3993 case SUPER: return high ?
3994 makeSuperWildcard(syms.botType, formal) :
3995 makeSuperWildcard(B(bound), formal);
3996 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
3997 default:
3998 Assert.error("Invalid bound kind " + bk);
3999 return null;
4000 }
4001 }
4003 Type B(Type t) {
4004 while (t.tag == WILDCARD) {
4005 WildcardType w = (WildcardType)t;
4006 t = high ?
4007 w.getExtendsBound() :
4008 w.getSuperBound();
4009 if (t == null) {
4010 t = high ? syms.objectType : syms.botType;
4011 }
4012 }
4013 return t;
4014 }
4015 }
4018 /**
4019 * Create a wildcard with the given upper (extends) bound; create
4020 * an unbounded wildcard if bound is Object.
4021 *
4022 * @param bound the upper bound
4023 * @param formal the formal type parameter that will be
4024 * substituted by the wildcard
4025 */
4026 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
4027 if (bound == syms.objectType) {
4028 return new WildcardType(syms.objectType,
4029 BoundKind.UNBOUND,
4030 syms.boundClass,
4031 formal);
4032 } else {
4033 return new WildcardType(bound,
4034 BoundKind.EXTENDS,
4035 syms.boundClass,
4036 formal);
4037 }
4038 }
4040 /**
4041 * Create a wildcard with the given lower (super) bound; create an
4042 * unbounded wildcard if bound is bottom (type of {@code null}).
4043 *
4044 * @param bound the lower bound
4045 * @param formal the formal type parameter that will be
4046 * substituted by the wildcard
4047 */
4048 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
4049 if (bound.tag == BOT) {
4050 return new WildcardType(syms.objectType,
4051 BoundKind.UNBOUND,
4052 syms.boundClass,
4053 formal);
4054 } else {
4055 return new WildcardType(bound,
4056 BoundKind.SUPER,
4057 syms.boundClass,
4058 formal);
4059 }
4060 }
4062 /**
4063 * A wrapper for a type that allows use in sets.
4064 */
4065 class SingletonType {
4066 final Type t;
4067 SingletonType(Type t) {
4068 this.t = t;
4069 }
4070 public int hashCode() {
4071 return Types.hashCode(t);
4072 }
4073 public boolean equals(Object obj) {
4074 return (obj instanceof SingletonType) &&
4075 isSameType(t, ((SingletonType)obj).t);
4076 }
4077 public String toString() {
4078 return t.toString();
4079 }
4080 }
4081 // </editor-fold>
4083 // <editor-fold defaultstate="collapsed" desc="Visitors">
4084 /**
4085 * A default visitor for types. All visitor methods except
4086 * visitType are implemented by delegating to visitType. Concrete
4087 * subclasses must provide an implementation of visitType and can
4088 * override other methods as needed.
4089 *
4090 * @param <R> the return type of the operation implemented by this
4091 * visitor; use Void if no return type is needed.
4092 * @param <S> the type of the second argument (the first being the
4093 * type itself) of the operation implemented by this visitor; use
4094 * Void if a second argument is not needed.
4095 */
4096 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
4097 final public R visit(Type t, S s) { return t.accept(this, s); }
4098 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
4099 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
4100 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
4101 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
4102 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
4103 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
4104 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
4105 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
4106 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
4107 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
4108 }
4110 /**
4111 * A default visitor for symbols. All visitor methods except
4112 * visitSymbol are implemented by delegating to visitSymbol. Concrete
4113 * subclasses must provide an implementation of visitSymbol and can
4114 * override other methods as needed.
4115 *
4116 * @param <R> the return type of the operation implemented by this
4117 * visitor; use Void if no return type is needed.
4118 * @param <S> the type of the second argument (the first being the
4119 * symbol itself) of the operation implemented by this visitor; use
4120 * Void if a second argument is not needed.
4121 */
4122 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
4123 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
4124 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
4125 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
4126 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
4127 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
4128 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
4129 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
4130 }
4132 /**
4133 * A <em>simple</em> visitor for types. This visitor is simple as
4134 * captured wildcards, for-all types (generic methods), and
4135 * undetermined type variables (part of inference) are hidden.
4136 * Captured wildcards are hidden by treating them as type
4137 * variables and the rest are hidden by visiting their qtypes.
4138 *
4139 * @param <R> the return type of the operation implemented by this
4140 * visitor; use Void if no return type is needed.
4141 * @param <S> the type of the second argument (the first being the
4142 * type itself) of the operation implemented by this visitor; use
4143 * Void if a second argument is not needed.
4144 */
4145 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
4146 @Override
4147 public R visitCapturedType(CapturedType t, S s) {
4148 return visitTypeVar(t, s);
4149 }
4150 @Override
4151 public R visitForAll(ForAll t, S s) {
4152 return visit(t.qtype, s);
4153 }
4154 @Override
4155 public R visitUndetVar(UndetVar t, S s) {
4156 return visit(t.qtype, s);
4157 }
4158 }
4160 /**
4161 * A plain relation on types. That is a 2-ary function on the
4162 * form Type × Type → Boolean.
4163 * <!-- In plain text: Type x Type -> Boolean -->
4164 */
4165 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
4167 /**
4168 * A convenience visitor for implementing operations that only
4169 * require one argument (the type itself), that is, unary
4170 * operations.
4171 *
4172 * @param <R> the return type of the operation implemented by this
4173 * visitor; use Void if no return type is needed.
4174 */
4175 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
4176 final public R visit(Type t) { return t.accept(this, null); }
4177 }
4179 /**
4180 * A visitor for implementing a mapping from types to types. The
4181 * default behavior of this class is to implement the identity
4182 * mapping (mapping a type to itself). This can be overridden in
4183 * subclasses.
4184 *
4185 * @param <S> the type of the second argument (the first being the
4186 * type itself) of this mapping; use Void if a second argument is
4187 * not needed.
4188 */
4189 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
4190 final public Type visit(Type t) { return t.accept(this, null); }
4191 public Type visitType(Type t, S s) { return t; }
4192 }
4193 // </editor-fold>
4196 // <editor-fold defaultstate="collapsed" desc="Annotation support">
4198 public RetentionPolicy getRetention(Attribute.Compound a) {
4199 return getRetention(a.type.tsym);
4200 }
4202 public RetentionPolicy getRetention(Symbol sym) {
4203 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
4204 Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
4205 if (c != null) {
4206 Attribute value = c.member(names.value);
4207 if (value != null && value instanceof Attribute.Enum) {
4208 Name levelName = ((Attribute.Enum)value).value.name;
4209 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
4210 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
4211 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
4212 else ;// /* fail soft */ throw new AssertionError(levelName);
4213 }
4214 }
4215 return vis;
4216 }
4217 // </editor-fold>
4218 }
