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src/share/classes/com/sun/tools/javac/code/Types.java@2ca5866a8dfb
src/share/classes/com/sun/tools/javac/code/Types.java
Fri, 10 Dec 2010 15:23:42 +0000
- author
- mcimadamore
- date
- Fri, 10 Dec 2010 15:23:42 +0000
- changeset 786
- 2ca5866a8dfb
- parent 780
- 1d625fbe6c22
- child 787
- b1c98bfd4709
- permissions
- -rw-r--r--
7005671: Regression: compiler accepts invalid cast from X[] to primitive array
Summary: regression in type conversion after 292 changes
Reviewed-by: jjg
1 /*
2 * Copyright (c) 2003, 2009, 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.*;
31 import com.sun.tools.javac.util.*;
32 import com.sun.tools.javac.util.List;
34 import com.sun.tools.javac.jvm.ClassReader;
35 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
36 import com.sun.tools.javac.comp.Check;
38 import static com.sun.tools.javac.code.Type.*;
39 import static com.sun.tools.javac.code.TypeTags.*;
40 import static com.sun.tools.javac.code.Symbol.*;
41 import static com.sun.tools.javac.code.Flags.*;
42 import static com.sun.tools.javac.code.BoundKind.*;
43 import static com.sun.tools.javac.util.ListBuffer.lb;
45 /**
46 * Utility class containing various operations on types.
47 *
48 * <p>Unless other names are more illustrative, the following naming
49 * conventions should be observed in this file:
50 *
51 * <dl>
52 * <dt>t</dt>
53 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
54 * <dt>s</dt>
55 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
56 * <dt>ts</dt>
57 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
58 * <dt>ss</dt>
59 * <dd>A second list of types should be named ss.</dd>
60 * </dl>
61 *
62 * <p><b>This is NOT part of any supported API.
63 * If you write code that depends on this, you do so at your own risk.
64 * This code and its internal interfaces are subject to change or
65 * deletion without notice.</b>
66 */
67 public class Types {
68 protected static final Context.Key<Types> typesKey =
69 new Context.Key<Types>();
71 final Symtab syms;
72 final Scope.ScopeCounter scopeCounter;
73 final JavacMessages messages;
74 final Names names;
75 final boolean allowBoxing;
76 final ClassReader reader;
77 final Source source;
78 final Check chk;
79 List<Warner> warnStack = List.nil();
80 final Name capturedName;
82 // <editor-fold defaultstate="collapsed" desc="Instantiating">
83 public static Types instance(Context context) {
84 Types instance = context.get(typesKey);
85 if (instance == null)
86 instance = new Types(context);
87 return instance;
88 }
90 protected Types(Context context) {
91 context.put(typesKey, this);
92 syms = Symtab.instance(context);
93 scopeCounter = Scope.ScopeCounter.instance(context);
94 names = Names.instance(context);
95 allowBoxing = Source.instance(context).allowBoxing();
96 reader = ClassReader.instance(context);
97 source = Source.instance(context);
98 chk = Check.instance(context);
99 capturedName = names.fromString("<captured wildcard>");
100 messages = JavacMessages.instance(context);
101 }
102 // </editor-fold>
104 // <editor-fold defaultstate="collapsed" desc="upperBound">
105 /**
106 * The "rvalue conversion".<br>
107 * The upper bound of most types is the type
108 * itself. Wildcards, on the other hand have upper
109 * and lower bounds.
110 * @param t a type
111 * @return the upper bound of the given type
112 */
113 public Type upperBound(Type t) {
114 return upperBound.visit(t);
115 }
116 // where
117 private final MapVisitor<Void> upperBound = new MapVisitor<Void>() {
119 @Override
120 public Type visitWildcardType(WildcardType t, Void ignored) {
121 if (t.isSuperBound())
122 return t.bound == null ? syms.objectType : t.bound.bound;
123 else
124 return visit(t.type);
125 }
127 @Override
128 public Type visitCapturedType(CapturedType t, Void ignored) {
129 return visit(t.bound);
130 }
131 };
132 // </editor-fold>
134 // <editor-fold defaultstate="collapsed" desc="lowerBound">
135 /**
136 * The "lvalue conversion".<br>
137 * The lower bound of most types is the type
138 * itself. Wildcards, on the other hand have upper
139 * and lower bounds.
140 * @param t a type
141 * @return the lower bound of the given type
142 */
143 public Type lowerBound(Type t) {
144 return lowerBound.visit(t);
145 }
146 // where
147 private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() {
149 @Override
150 public Type visitWildcardType(WildcardType t, Void ignored) {
151 return t.isExtendsBound() ? syms.botType : visit(t.type);
152 }
154 @Override
155 public Type visitCapturedType(CapturedType t, Void ignored) {
156 return visit(t.getLowerBound());
157 }
158 };
159 // </editor-fold>
161 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
162 /**
163 * Checks that all the arguments to a class are unbounded
164 * wildcards or something else that doesn't make any restrictions
165 * on the arguments. If a class isUnbounded, a raw super- or
166 * subclass can be cast to it without a warning.
167 * @param t a type
168 * @return true iff the given type is unbounded or raw
169 */
170 public boolean isUnbounded(Type t) {
171 return isUnbounded.visit(t);
172 }
173 // where
174 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
176 public Boolean visitType(Type t, Void ignored) {
177 return true;
178 }
180 @Override
181 public Boolean visitClassType(ClassType t, Void ignored) {
182 List<Type> parms = t.tsym.type.allparams();
183 List<Type> args = t.allparams();
184 while (parms.nonEmpty()) {
185 WildcardType unb = new WildcardType(syms.objectType,
186 BoundKind.UNBOUND,
187 syms.boundClass,
188 (TypeVar)parms.head);
189 if (!containsType(args.head, unb))
190 return false;
191 parms = parms.tail;
192 args = args.tail;
193 }
194 return true;
195 }
196 };
197 // </editor-fold>
199 // <editor-fold defaultstate="collapsed" desc="asSub">
200 /**
201 * Return the least specific subtype of t that starts with symbol
202 * sym. If none exists, return null. The least specific subtype
203 * is determined as follows:
204 *
205 * <p>If there is exactly one parameterized instance of sym that is a
206 * subtype of t, that parameterized instance is returned.<br>
207 * Otherwise, if the plain type or raw type `sym' is a subtype of
208 * type t, the type `sym' itself is returned. Otherwise, null is
209 * returned.
210 */
211 public Type asSub(Type t, Symbol sym) {
212 return asSub.visit(t, sym);
213 }
214 // where
215 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
217 public Type visitType(Type t, Symbol sym) {
218 return null;
219 }
221 @Override
222 public Type visitClassType(ClassType t, Symbol sym) {
223 if (t.tsym == sym)
224 return t;
225 Type base = asSuper(sym.type, t.tsym);
226 if (base == null)
227 return null;
228 ListBuffer<Type> from = new ListBuffer<Type>();
229 ListBuffer<Type> to = new ListBuffer<Type>();
230 try {
231 adapt(base, t, from, to);
232 } catch (AdaptFailure ex) {
233 return null;
234 }
235 Type res = subst(sym.type, from.toList(), to.toList());
236 if (!isSubtype(res, t))
237 return null;
238 ListBuffer<Type> openVars = new ListBuffer<Type>();
239 for (List<Type> l = sym.type.allparams();
240 l.nonEmpty(); l = l.tail)
241 if (res.contains(l.head) && !t.contains(l.head))
242 openVars.append(l.head);
243 if (openVars.nonEmpty()) {
244 if (t.isRaw()) {
245 // The subtype of a raw type is raw
246 res = erasure(res);
247 } else {
248 // Unbound type arguments default to ?
249 List<Type> opens = openVars.toList();
250 ListBuffer<Type> qs = new ListBuffer<Type>();
251 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
252 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head));
253 }
254 res = subst(res, opens, qs.toList());
255 }
256 }
257 return res;
258 }
260 @Override
261 public Type visitErrorType(ErrorType t, Symbol sym) {
262 return t;
263 }
264 };
265 // </editor-fold>
267 // <editor-fold defaultstate="collapsed" desc="isConvertible">
268 /**
269 * Is t a subtype of or convertiable via boxing/unboxing
270 * convertions to s?
271 */
272 public boolean isConvertible(Type t, Type s, Warner warn) {
273 boolean tPrimitive = t.isPrimitive();
274 boolean sPrimitive = s.isPrimitive();
275 if (tPrimitive == sPrimitive)
276 return isSubtypeUnchecked(t, s, warn);
277 if (!allowBoxing) return false;
278 return tPrimitive
279 ? isSubtype(boxedClass(t).type, s)
280 : isSubtype(unboxedType(t), s);
281 }
283 /**
284 * Is t a subtype of or convertiable via boxing/unboxing
285 * convertions to s?
286 */
287 public boolean isConvertible(Type t, Type s) {
288 return isConvertible(t, s, Warner.noWarnings);
289 }
290 // </editor-fold>
292 // <editor-fold defaultstate="collapsed" desc="isSubtype">
293 /**
294 * Is t an unchecked subtype of s?
295 */
296 public boolean isSubtypeUnchecked(Type t, Type s) {
297 return isSubtypeUnchecked(t, s, Warner.noWarnings);
298 }
299 /**
300 * Is t an unchecked subtype of s?
301 */
302 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
303 if (t.tag == ARRAY && s.tag == ARRAY) {
304 return (((ArrayType)t).elemtype.tag <= lastBaseTag)
305 ? isSameType(elemtype(t), elemtype(s))
306 : isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
307 } else if (isSubtype(t, s)) {
308 return true;
309 }
310 else if (t.tag == TYPEVAR) {
311 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
312 }
313 else if (s.tag == UNDETVAR) {
314 UndetVar uv = (UndetVar)s;
315 if (uv.inst != null)
316 return isSubtypeUnchecked(t, uv.inst, warn);
317 }
318 else if (!s.isRaw()) {
319 Type t2 = asSuper(t, s.tsym);
320 if (t2 != null && t2.isRaw()) {
321 if (isReifiable(s))
322 warn.silentUnchecked();
323 else
324 warn.warnUnchecked();
325 return true;
326 }
327 }
328 return false;
329 }
331 /**
332 * Is t a subtype of s?<br>
333 * (not defined for Method and ForAll types)
334 */
335 final public boolean isSubtype(Type t, Type s) {
336 return isSubtype(t, s, true);
337 }
338 final public boolean isSubtypeNoCapture(Type t, Type s) {
339 return isSubtype(t, s, false);
340 }
341 public boolean isSubtype(Type t, Type s, boolean capture) {
342 if (t == s)
343 return true;
345 if (s.tag >= firstPartialTag)
346 return isSuperType(s, t);
348 if (s.isCompound()) {
349 for (Type s2 : interfaces(s).prepend(supertype(s))) {
350 if (!isSubtype(t, s2, capture))
351 return false;
352 }
353 return true;
354 }
356 Type lower = lowerBound(s);
357 if (s != lower)
358 return isSubtype(capture ? capture(t) : t, lower, false);
360 return isSubtype.visit(capture ? capture(t) : t, s);
361 }
362 // where
363 private TypeRelation isSubtype = new TypeRelation()
364 {
365 public Boolean visitType(Type t, Type s) {
366 switch (t.tag) {
367 case BYTE: case CHAR:
368 return (t.tag == s.tag ||
369 t.tag + 2 <= s.tag && s.tag <= DOUBLE);
370 case SHORT: case INT: case LONG: case FLOAT: case DOUBLE:
371 return t.tag <= s.tag && s.tag <= DOUBLE;
372 case BOOLEAN: case VOID:
373 return t.tag == s.tag;
374 case TYPEVAR:
375 return isSubtypeNoCapture(t.getUpperBound(), s);
376 case BOT:
377 return
378 s.tag == BOT || s.tag == CLASS ||
379 s.tag == ARRAY || s.tag == TYPEVAR;
380 case NONE:
381 return false;
382 default:
383 throw new AssertionError("isSubtype " + t.tag);
384 }
385 }
387 private Set<TypePair> cache = new HashSet<TypePair>();
389 private boolean containsTypeRecursive(Type t, Type s) {
390 TypePair pair = new TypePair(t, s);
391 if (cache.add(pair)) {
392 try {
393 return containsType(t.getTypeArguments(),
394 s.getTypeArguments());
395 } finally {
396 cache.remove(pair);
397 }
398 } else {
399 return containsType(t.getTypeArguments(),
400 rewriteSupers(s).getTypeArguments());
401 }
402 }
404 private Type rewriteSupers(Type t) {
405 if (!t.isParameterized())
406 return t;
407 ListBuffer<Type> from = lb();
408 ListBuffer<Type> to = lb();
409 adaptSelf(t, from, to);
410 if (from.isEmpty())
411 return t;
412 ListBuffer<Type> rewrite = lb();
413 boolean changed = false;
414 for (Type orig : to.toList()) {
415 Type s = rewriteSupers(orig);
416 if (s.isSuperBound() && !s.isExtendsBound()) {
417 s = new WildcardType(syms.objectType,
418 BoundKind.UNBOUND,
419 syms.boundClass);
420 changed = true;
421 } else if (s != orig) {
422 s = new WildcardType(upperBound(s),
423 BoundKind.EXTENDS,
424 syms.boundClass);
425 changed = true;
426 }
427 rewrite.append(s);
428 }
429 if (changed)
430 return subst(t.tsym.type, from.toList(), rewrite.toList());
431 else
432 return t;
433 }
435 @Override
436 public Boolean visitClassType(ClassType t, Type s) {
437 Type sup = asSuper(t, s.tsym);
438 return sup != null
439 && sup.tsym == s.tsym
440 // You're not allowed to write
441 // Vector<Object> vec = new Vector<String>();
442 // But with wildcards you can write
443 // Vector<? extends Object> vec = new Vector<String>();
444 // which means that subtype checking must be done
445 // here instead of same-type checking (via containsType).
446 && (!s.isParameterized() || containsTypeRecursive(s, sup))
447 && isSubtypeNoCapture(sup.getEnclosingType(),
448 s.getEnclosingType());
449 }
451 @Override
452 public Boolean visitArrayType(ArrayType t, Type s) {
453 if (s.tag == ARRAY) {
454 if (t.elemtype.tag <= lastBaseTag)
455 return isSameType(t.elemtype, elemtype(s));
456 else
457 return isSubtypeNoCapture(t.elemtype, elemtype(s));
458 }
460 if (s.tag == CLASS) {
461 Name sname = s.tsym.getQualifiedName();
462 return sname == names.java_lang_Object
463 || sname == names.java_lang_Cloneable
464 || sname == names.java_io_Serializable;
465 }
467 return false;
468 }
470 @Override
471 public Boolean visitUndetVar(UndetVar t, Type s) {
472 //todo: test against origin needed? or replace with substitution?
473 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
474 return true;
476 if (t.inst != null)
477 return isSubtypeNoCapture(t.inst, s); // TODO: ", warn"?
479 t.hibounds = t.hibounds.prepend(s);
480 return true;
481 }
483 @Override
484 public Boolean visitErrorType(ErrorType t, Type s) {
485 return true;
486 }
487 };
489 /**
490 * Is t a subtype of every type in given list `ts'?<br>
491 * (not defined for Method and ForAll types)<br>
492 * Allows unchecked conversions.
493 */
494 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
495 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
496 if (!isSubtypeUnchecked(t, l.head, warn))
497 return false;
498 return true;
499 }
501 /**
502 * Are corresponding elements of ts subtypes of ss? If lists are
503 * of different length, return false.
504 */
505 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
506 while (ts.tail != null && ss.tail != null
507 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
508 isSubtype(ts.head, ss.head)) {
509 ts = ts.tail;
510 ss = ss.tail;
511 }
512 return ts.tail == null && ss.tail == null;
513 /*inlined: ts.isEmpty() && ss.isEmpty();*/
514 }
516 /**
517 * Are corresponding elements of ts subtypes of ss, allowing
518 * unchecked conversions? If lists are of different length,
519 * return false.
520 **/
521 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
522 while (ts.tail != null && ss.tail != null
523 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
524 isSubtypeUnchecked(ts.head, ss.head, warn)) {
525 ts = ts.tail;
526 ss = ss.tail;
527 }
528 return ts.tail == null && ss.tail == null;
529 /*inlined: ts.isEmpty() && ss.isEmpty();*/
530 }
531 // </editor-fold>
533 // <editor-fold defaultstate="collapsed" desc="isSuperType">
534 /**
535 * Is t a supertype of s?
536 */
537 public boolean isSuperType(Type t, Type s) {
538 switch (t.tag) {
539 case ERROR:
540 return true;
541 case UNDETVAR: {
542 UndetVar undet = (UndetVar)t;
543 if (t == s ||
544 undet.qtype == s ||
545 s.tag == ERROR ||
546 s.tag == BOT) return true;
547 if (undet.inst != null)
548 return isSubtype(s, undet.inst);
549 undet.lobounds = undet.lobounds.prepend(s);
550 return true;
551 }
552 default:
553 return isSubtype(s, t);
554 }
555 }
556 // </editor-fold>
558 // <editor-fold defaultstate="collapsed" desc="isSameType">
559 /**
560 * Are corresponding elements of the lists the same type? If
561 * lists are of different length, return false.
562 */
563 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
564 while (ts.tail != null && ss.tail != null
565 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
566 isSameType(ts.head, ss.head)) {
567 ts = ts.tail;
568 ss = ss.tail;
569 }
570 return ts.tail == null && ss.tail == null;
571 /*inlined: ts.isEmpty() && ss.isEmpty();*/
572 }
574 /**
575 * Is t the same type as s?
576 */
577 public boolean isSameType(Type t, Type s) {
578 return isSameType.visit(t, s);
579 }
580 // where
581 private TypeRelation isSameType = new TypeRelation() {
583 public Boolean visitType(Type t, Type s) {
584 if (t == s)
585 return true;
587 if (s.tag >= firstPartialTag)
588 return visit(s, t);
590 switch (t.tag) {
591 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
592 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
593 return t.tag == s.tag;
594 case TYPEVAR: {
595 if (s.tag == TYPEVAR) {
596 //type-substitution does not preserve type-var types
597 //check that type var symbols and bounds are indeed the same
598 return t.tsym == s.tsym &&
599 visit(t.getUpperBound(), s.getUpperBound());
600 }
601 else {
602 //special case for s == ? super X, where upper(s) = u
603 //check that u == t, where u has been set by Type.withTypeVar
604 return s.isSuperBound() &&
605 !s.isExtendsBound() &&
606 visit(t, upperBound(s));
607 }
608 }
609 default:
610 throw new AssertionError("isSameType " + t.tag);
611 }
612 }
614 @Override
615 public Boolean visitWildcardType(WildcardType t, Type s) {
616 if (s.tag >= firstPartialTag)
617 return visit(s, t);
618 else
619 return false;
620 }
622 @Override
623 public Boolean visitClassType(ClassType t, Type s) {
624 if (t == s)
625 return true;
627 if (s.tag >= firstPartialTag)
628 return visit(s, t);
630 if (s.isSuperBound() && !s.isExtendsBound())
631 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
633 if (t.isCompound() && s.isCompound()) {
634 if (!visit(supertype(t), supertype(s)))
635 return false;
637 HashSet<SingletonType> set = new HashSet<SingletonType>();
638 for (Type x : interfaces(t))
639 set.add(new SingletonType(x));
640 for (Type x : interfaces(s)) {
641 if (!set.remove(new SingletonType(x)))
642 return false;
643 }
644 return (set.size() == 0);
645 }
646 return t.tsym == s.tsym
647 && visit(t.getEnclosingType(), s.getEnclosingType())
648 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
649 }
651 @Override
652 public Boolean visitArrayType(ArrayType t, Type s) {
653 if (t == s)
654 return true;
656 if (s.tag >= firstPartialTag)
657 return visit(s, t);
659 return s.tag == ARRAY
660 && containsTypeEquivalent(t.elemtype, elemtype(s));
661 }
663 @Override
664 public Boolean visitMethodType(MethodType t, Type s) {
665 // isSameType for methods does not take thrown
666 // exceptions into account!
667 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
668 }
670 @Override
671 public Boolean visitPackageType(PackageType t, Type s) {
672 return t == s;
673 }
675 @Override
676 public Boolean visitForAll(ForAll t, Type s) {
677 if (s.tag != FORALL)
678 return false;
680 ForAll forAll = (ForAll)s;
681 return hasSameBounds(t, forAll)
682 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
683 }
685 @Override
686 public Boolean visitUndetVar(UndetVar t, Type s) {
687 if (s.tag == WILDCARD)
688 // FIXME, this might be leftovers from before capture conversion
689 return false;
691 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
692 return true;
694 if (t.inst != null)
695 return visit(t.inst, s);
697 t.inst = fromUnknownFun.apply(s);
698 for (List<Type> l = t.lobounds; l.nonEmpty(); l = l.tail) {
699 if (!isSubtype(l.head, t.inst))
700 return false;
701 }
702 for (List<Type> l = t.hibounds; l.nonEmpty(); l = l.tail) {
703 if (!isSubtype(t.inst, l.head))
704 return false;
705 }
706 return true;
707 }
709 @Override
710 public Boolean visitErrorType(ErrorType t, Type s) {
711 return true;
712 }
713 };
714 // </editor-fold>
716 // <editor-fold defaultstate="collapsed" desc="fromUnknownFun">
717 /**
718 * A mapping that turns all unknown types in this type to fresh
719 * unknown variables.
720 */
721 public Mapping fromUnknownFun = new Mapping("fromUnknownFun") {
722 public Type apply(Type t) {
723 if (t.tag == UNKNOWN) return new UndetVar(t);
724 else return t.map(this);
725 }
726 };
727 // </editor-fold>
729 // <editor-fold defaultstate="collapsed" desc="Contains Type">
730 public boolean containedBy(Type t, Type s) {
731 switch (t.tag) {
732 case UNDETVAR:
733 if (s.tag == WILDCARD) {
734 UndetVar undetvar = (UndetVar)t;
735 WildcardType wt = (WildcardType)s;
736 switch(wt.kind) {
737 case UNBOUND: //similar to ? extends Object
738 case EXTENDS: {
739 Type bound = upperBound(s);
740 // We should check the new upper bound against any of the
741 // undetvar's lower bounds.
742 for (Type t2 : undetvar.lobounds) {
743 if (!isSubtype(t2, bound))
744 return false;
745 }
746 undetvar.hibounds = undetvar.hibounds.prepend(bound);
747 break;
748 }
749 case SUPER: {
750 Type bound = lowerBound(s);
751 // We should check the new lower bound against any of the
752 // undetvar's lower bounds.
753 for (Type t2 : undetvar.hibounds) {
754 if (!isSubtype(bound, t2))
755 return false;
756 }
757 undetvar.lobounds = undetvar.lobounds.prepend(bound);
758 break;
759 }
760 }
761 return true;
762 } else {
763 return isSameType(t, s);
764 }
765 case ERROR:
766 return true;
767 default:
768 return containsType(s, t);
769 }
770 }
772 boolean containsType(List<Type> ts, List<Type> ss) {
773 while (ts.nonEmpty() && ss.nonEmpty()
774 && containsType(ts.head, ss.head)) {
775 ts = ts.tail;
776 ss = ss.tail;
777 }
778 return ts.isEmpty() && ss.isEmpty();
779 }
781 /**
782 * Check if t contains s.
783 *
784 * <p>T contains S if:
785 *
786 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
787 *
788 * <p>This relation is only used by ClassType.isSubtype(), that
789 * is,
790 *
791 * <p>{@code C<S> <: C<T> if T contains S.}
792 *
793 * <p>Because of F-bounds, this relation can lead to infinite
794 * recursion. Thus we must somehow break that recursion. Notice
795 * that containsType() is only called from ClassType.isSubtype().
796 * Since the arguments have already been checked against their
797 * bounds, we know:
798 *
799 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
800 *
801 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
802 *
803 * @param t a type
804 * @param s a type
805 */
806 public boolean containsType(Type t, Type s) {
807 return containsType.visit(t, s);
808 }
809 // where
810 private TypeRelation containsType = new TypeRelation() {
812 private Type U(Type t) {
813 while (t.tag == WILDCARD) {
814 WildcardType w = (WildcardType)t;
815 if (w.isSuperBound())
816 return w.bound == null ? syms.objectType : w.bound.bound;
817 else
818 t = w.type;
819 }
820 return t;
821 }
823 private Type L(Type t) {
824 while (t.tag == WILDCARD) {
825 WildcardType w = (WildcardType)t;
826 if (w.isExtendsBound())
827 return syms.botType;
828 else
829 t = w.type;
830 }
831 return t;
832 }
834 public Boolean visitType(Type t, Type s) {
835 if (s.tag >= firstPartialTag)
836 return containedBy(s, t);
837 else
838 return isSameType(t, s);
839 }
841 void debugContainsType(WildcardType t, Type s) {
842 System.err.println();
843 System.err.format(" does %s contain %s?%n", t, s);
844 System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
845 upperBound(s), s, t, U(t),
846 t.isSuperBound()
847 || isSubtypeNoCapture(upperBound(s), U(t)));
848 System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
849 L(t), t, s, lowerBound(s),
850 t.isExtendsBound()
851 || isSubtypeNoCapture(L(t), lowerBound(s)));
852 System.err.println();
853 }
855 @Override
856 public Boolean visitWildcardType(WildcardType t, Type s) {
857 if (s.tag >= firstPartialTag)
858 return containedBy(s, t);
859 else {
860 // debugContainsType(t, s);
861 return isSameWildcard(t, s)
862 || isCaptureOf(s, t)
863 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
864 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
865 }
866 }
868 @Override
869 public Boolean visitUndetVar(UndetVar t, Type s) {
870 if (s.tag != WILDCARD)
871 return isSameType(t, s);
872 else
873 return false;
874 }
876 @Override
877 public Boolean visitErrorType(ErrorType t, Type s) {
878 return true;
879 }
880 };
882 public boolean isCaptureOf(Type s, WildcardType t) {
883 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
884 return false;
885 return isSameWildcard(t, ((CapturedType)s).wildcard);
886 }
888 public boolean isSameWildcard(WildcardType t, Type s) {
889 if (s.tag != WILDCARD)
890 return false;
891 WildcardType w = (WildcardType)s;
892 return w.kind == t.kind && w.type == t.type;
893 }
895 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
896 while (ts.nonEmpty() && ss.nonEmpty()
897 && containsTypeEquivalent(ts.head, ss.head)) {
898 ts = ts.tail;
899 ss = ss.tail;
900 }
901 return ts.isEmpty() && ss.isEmpty();
902 }
903 // </editor-fold>
905 // <editor-fold defaultstate="collapsed" desc="isCastable">
906 public boolean isCastable(Type t, Type s) {
907 return isCastable(t, s, Warner.noWarnings);
908 }
910 /**
911 * Is t is castable to s?<br>
912 * s is assumed to be an erased type.<br>
913 * (not defined for Method and ForAll types).
914 */
915 public boolean isCastable(Type t, Type s, Warner warn) {
916 if (t == s)
917 return true;
919 if (t.isPrimitive() != s.isPrimitive())
920 return allowBoxing && (isConvertible(t, s, warn) || isConvertible(s, t, warn));
922 if (warn != warnStack.head) {
923 try {
924 warnStack = warnStack.prepend(warn);
925 return isCastable.visit(t,s);
926 } finally {
927 warnStack = warnStack.tail;
928 }
929 } else {
930 return isCastable.visit(t,s);
931 }
932 }
933 // where
934 private TypeRelation isCastable = new TypeRelation() {
936 public Boolean visitType(Type t, Type s) {
937 if (s.tag == ERROR)
938 return true;
940 switch (t.tag) {
941 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
942 case DOUBLE:
943 return s.tag <= DOUBLE;
944 case BOOLEAN:
945 return s.tag == BOOLEAN;
946 case VOID:
947 return false;
948 case BOT:
949 return isSubtype(t, s);
950 default:
951 throw new AssertionError();
952 }
953 }
955 @Override
956 public Boolean visitWildcardType(WildcardType t, Type s) {
957 return isCastable(upperBound(t), s, warnStack.head);
958 }
960 @Override
961 public Boolean visitClassType(ClassType t, Type s) {
962 if (s.tag == ERROR || s.tag == BOT)
963 return true;
965 if (s.tag == TYPEVAR) {
966 if (isCastable(t, s.getUpperBound(), Warner.noWarnings)) {
967 warnStack.head.warnUnchecked();
968 return true;
969 } else {
970 return false;
971 }
972 }
974 if (t.isCompound()) {
975 Warner oldWarner = warnStack.head;
976 warnStack.head = Warner.noWarnings;
977 if (!visit(supertype(t), s))
978 return false;
979 for (Type intf : interfaces(t)) {
980 if (!visit(intf, s))
981 return false;
982 }
983 if (warnStack.head.unchecked == true)
984 oldWarner.warnUnchecked();
985 return true;
986 }
988 if (s.isCompound()) {
989 // call recursively to reuse the above code
990 return visitClassType((ClassType)s, t);
991 }
993 if (s.tag == CLASS || s.tag == ARRAY) {
994 boolean upcast;
995 if ((upcast = isSubtype(erasure(t), erasure(s)))
996 || isSubtype(erasure(s), erasure(t))) {
997 if (!upcast && s.tag == ARRAY) {
998 if (!isReifiable(s))
999 warnStack.head.warnUnchecked();
1000 return true;
1001 } else if (s.isRaw()) {
1002 return true;
1003 } else if (t.isRaw()) {
1004 if (!isUnbounded(s))
1005 warnStack.head.warnUnchecked();
1006 return true;
1007 }
1008 // Assume |a| <: |b|
1009 final Type a = upcast ? t : s;
1010 final Type b = upcast ? s : t;
1011 final boolean HIGH = true;
1012 final boolean LOW = false;
1013 final boolean DONT_REWRITE_TYPEVARS = false;
1014 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1015 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1016 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1017 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1018 Type lowSub = asSub(bLow, aLow.tsym);
1019 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1020 if (highSub == null) {
1021 final boolean REWRITE_TYPEVARS = true;
1022 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1023 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1024 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1025 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1026 lowSub = asSub(bLow, aLow.tsym);
1027 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1028 }
1029 if (highSub != null) {
1030 assert a.tsym == highSub.tsym && a.tsym == lowSub.tsym
1031 : a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym;
1032 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1033 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1034 && !disjointTypes(aLow.allparams(), highSub.allparams())
1035 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1036 if (upcast ? giveWarning(a, b) :
1037 giveWarning(b, a))
1038 warnStack.head.warnUnchecked();
1039 return true;
1040 }
1041 }
1042 if (isReifiable(s))
1043 return isSubtypeUnchecked(a, b);
1044 else
1045 return isSubtypeUnchecked(a, b, warnStack.head);
1046 }
1048 // Sidecast
1049 if (s.tag == CLASS) {
1050 if ((s.tsym.flags() & INTERFACE) != 0) {
1051 return ((t.tsym.flags() & FINAL) == 0)
1052 ? sideCast(t, s, warnStack.head)
1053 : sideCastFinal(t, s, warnStack.head);
1054 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1055 return ((s.tsym.flags() & FINAL) == 0)
1056 ? sideCast(t, s, warnStack.head)
1057 : sideCastFinal(t, s, warnStack.head);
1058 } else {
1059 // unrelated class types
1060 return false;
1061 }
1062 }
1063 }
1064 return false;
1065 }
1067 @Override
1068 public Boolean visitArrayType(ArrayType t, Type s) {
1069 switch (s.tag) {
1070 case ERROR:
1071 case BOT:
1072 return true;
1073 case TYPEVAR:
1074 if (isCastable(s, t, Warner.noWarnings)) {
1075 warnStack.head.warnUnchecked();
1076 return true;
1077 } else {
1078 return false;
1079 }
1080 case CLASS:
1081 return isSubtype(t, s);
1082 case ARRAY:
1083 if (elemtype(t).tag <= lastBaseTag ||
1084 elemtype(s).tag <= lastBaseTag) {
1085 return elemtype(t).tag == elemtype(s).tag;
1086 } else {
1087 return visit(elemtype(t), elemtype(s));
1088 }
1089 default:
1090 return false;
1091 }
1092 }
1094 @Override
1095 public Boolean visitTypeVar(TypeVar t, Type s) {
1096 switch (s.tag) {
1097 case ERROR:
1098 case BOT:
1099 return true;
1100 case TYPEVAR:
1101 if (isSubtype(t, s)) {
1102 return true;
1103 } else if (isCastable(t.bound, s, Warner.noWarnings)) {
1104 warnStack.head.warnUnchecked();
1105 return true;
1106 } else {
1107 return false;
1108 }
1109 default:
1110 return isCastable(t.bound, s, warnStack.head);
1111 }
1112 }
1114 @Override
1115 public Boolean visitErrorType(ErrorType t, Type s) {
1116 return true;
1117 }
1118 };
1119 // </editor-fold>
1121 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1122 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1123 while (ts.tail != null && ss.tail != null) {
1124 if (disjointType(ts.head, ss.head)) return true;
1125 ts = ts.tail;
1126 ss = ss.tail;
1127 }
1128 return false;
1129 }
1131 /**
1132 * Two types or wildcards are considered disjoint if it can be
1133 * proven that no type can be contained in both. It is
1134 * conservative in that it is allowed to say that two types are
1135 * not disjoint, even though they actually are.
1136 *
1137 * The type C<X> is castable to C<Y> exactly if X and Y are not
1138 * disjoint.
1139 */
1140 public boolean disjointType(Type t, Type s) {
1141 return disjointType.visit(t, s);
1142 }
1143 // where
1144 private TypeRelation disjointType = new TypeRelation() {
1146 private Set<TypePair> cache = new HashSet<TypePair>();
1148 public Boolean visitType(Type t, Type s) {
1149 if (s.tag == WILDCARD)
1150 return visit(s, t);
1151 else
1152 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1153 }
1155 private boolean isCastableRecursive(Type t, Type s) {
1156 TypePair pair = new TypePair(t, s);
1157 if (cache.add(pair)) {
1158 try {
1159 return Types.this.isCastable(t, s);
1160 } finally {
1161 cache.remove(pair);
1162 }
1163 } else {
1164 return true;
1165 }
1166 }
1168 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1169 TypePair pair = new TypePair(t, s);
1170 if (cache.add(pair)) {
1171 try {
1172 return Types.this.notSoftSubtype(t, s);
1173 } finally {
1174 cache.remove(pair);
1175 }
1176 } else {
1177 return false;
1178 }
1179 }
1181 @Override
1182 public Boolean visitWildcardType(WildcardType t, Type s) {
1183 if (t.isUnbound())
1184 return false;
1186 if (s.tag != WILDCARD) {
1187 if (t.isExtendsBound())
1188 return notSoftSubtypeRecursive(s, t.type);
1189 else // isSuperBound()
1190 return notSoftSubtypeRecursive(t.type, s);
1191 }
1193 if (s.isUnbound())
1194 return false;
1196 if (t.isExtendsBound()) {
1197 if (s.isExtendsBound())
1198 return !isCastableRecursive(t.type, upperBound(s));
1199 else if (s.isSuperBound())
1200 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1201 } else if (t.isSuperBound()) {
1202 if (s.isExtendsBound())
1203 return notSoftSubtypeRecursive(t.type, upperBound(s));
1204 }
1205 return false;
1206 }
1207 };
1208 // </editor-fold>
1210 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1211 /**
1212 * Returns the lower bounds of the formals of a method.
1213 */
1214 public List<Type> lowerBoundArgtypes(Type t) {
1215 return map(t.getParameterTypes(), lowerBoundMapping);
1216 }
1217 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1218 public Type apply(Type t) {
1219 return lowerBound(t);
1220 }
1221 };
1222 // </editor-fold>
1224 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1225 /**
1226 * This relation answers the question: is impossible that
1227 * something of type `t' can be a subtype of `s'? This is
1228 * different from the question "is `t' not a subtype of `s'?"
1229 * when type variables are involved: Integer is not a subtype of T
1230 * where <T extends Number> but it is not true that Integer cannot
1231 * possibly be a subtype of T.
1232 */
1233 public boolean notSoftSubtype(Type t, Type s) {
1234 if (t == s) return false;
1235 if (t.tag == TYPEVAR) {
1236 TypeVar tv = (TypeVar) t;
1237 return !isCastable(tv.bound,
1238 relaxBound(s),
1239 Warner.noWarnings);
1240 }
1241 if (s.tag != WILDCARD)
1242 s = upperBound(s);
1244 return !isSubtype(t, relaxBound(s));
1245 }
1247 private Type relaxBound(Type t) {
1248 if (t.tag == TYPEVAR) {
1249 while (t.tag == TYPEVAR)
1250 t = t.getUpperBound();
1251 t = rewriteQuantifiers(t, true, true);
1252 }
1253 return t;
1254 }
1255 // </editor-fold>
1257 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1258 public boolean isReifiable(Type t) {
1259 return isReifiable.visit(t);
1260 }
1261 // where
1262 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1264 public Boolean visitType(Type t, Void ignored) {
1265 return true;
1266 }
1268 @Override
1269 public Boolean visitClassType(ClassType t, Void ignored) {
1270 if (t.isCompound())
1271 return false;
1272 else {
1273 if (!t.isParameterized())
1274 return true;
1276 for (Type param : t.allparams()) {
1277 if (!param.isUnbound())
1278 return false;
1279 }
1280 return true;
1281 }
1282 }
1284 @Override
1285 public Boolean visitArrayType(ArrayType t, Void ignored) {
1286 return visit(t.elemtype);
1287 }
1289 @Override
1290 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1291 return false;
1292 }
1293 };
1294 // </editor-fold>
1296 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1297 public boolean isArray(Type t) {
1298 while (t.tag == WILDCARD)
1299 t = upperBound(t);
1300 return t.tag == ARRAY;
1301 }
1303 /**
1304 * The element type of an array.
1305 */
1306 public Type elemtype(Type t) {
1307 switch (t.tag) {
1308 case WILDCARD:
1309 return elemtype(upperBound(t));
1310 case ARRAY:
1311 return ((ArrayType)t).elemtype;
1312 case FORALL:
1313 return elemtype(((ForAll)t).qtype);
1314 case ERROR:
1315 return t;
1316 default:
1317 return null;
1318 }
1319 }
1321 /**
1322 * Mapping to take element type of an arraytype
1323 */
1324 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1325 public Type apply(Type t) { return elemtype(t); }
1326 };
1328 /**
1329 * The number of dimensions of an array type.
1330 */
1331 public int dimensions(Type t) {
1332 int result = 0;
1333 while (t.tag == ARRAY) {
1334 result++;
1335 t = elemtype(t);
1336 }
1337 return result;
1338 }
1339 // </editor-fold>
1341 // <editor-fold defaultstate="collapsed" desc="asSuper">
1342 /**
1343 * Return the (most specific) base type of t that starts with the
1344 * given symbol. If none exists, return null.
1345 *
1346 * @param t a type
1347 * @param sym a symbol
1348 */
1349 public Type asSuper(Type t, Symbol sym) {
1350 return asSuper.visit(t, sym);
1351 }
1352 // where
1353 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1355 public Type visitType(Type t, Symbol sym) {
1356 return null;
1357 }
1359 @Override
1360 public Type visitClassType(ClassType t, Symbol sym) {
1361 if (t.tsym == sym)
1362 return t;
1364 Type st = supertype(t);
1365 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1366 Type x = asSuper(st, sym);
1367 if (x != null)
1368 return x;
1369 }
1370 if ((sym.flags() & INTERFACE) != 0) {
1371 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1372 Type x = asSuper(l.head, sym);
1373 if (x != null)
1374 return x;
1375 }
1376 }
1377 return null;
1378 }
1380 @Override
1381 public Type visitArrayType(ArrayType t, Symbol sym) {
1382 return isSubtype(t, sym.type) ? sym.type : null;
1383 }
1385 @Override
1386 public Type visitTypeVar(TypeVar t, Symbol sym) {
1387 if (t.tsym == sym)
1388 return t;
1389 else
1390 return asSuper(t.bound, sym);
1391 }
1393 @Override
1394 public Type visitErrorType(ErrorType t, Symbol sym) {
1395 return t;
1396 }
1397 };
1399 /**
1400 * Return the base type of t or any of its outer types that starts
1401 * with the given symbol. If none exists, return null.
1402 *
1403 * @param t a type
1404 * @param sym a symbol
1405 */
1406 public Type asOuterSuper(Type t, Symbol sym) {
1407 switch (t.tag) {
1408 case CLASS:
1409 do {
1410 Type s = asSuper(t, sym);
1411 if (s != null) return s;
1412 t = t.getEnclosingType();
1413 } while (t.tag == CLASS);
1414 return null;
1415 case ARRAY:
1416 return isSubtype(t, sym.type) ? sym.type : null;
1417 case TYPEVAR:
1418 return asSuper(t, sym);
1419 case ERROR:
1420 return t;
1421 default:
1422 return null;
1423 }
1424 }
1426 /**
1427 * Return the base type of t or any of its enclosing types that
1428 * starts with the given symbol. If none exists, return null.
1429 *
1430 * @param t a type
1431 * @param sym a symbol
1432 */
1433 public Type asEnclosingSuper(Type t, Symbol sym) {
1434 switch (t.tag) {
1435 case CLASS:
1436 do {
1437 Type s = asSuper(t, sym);
1438 if (s != null) return s;
1439 Type outer = t.getEnclosingType();
1440 t = (outer.tag == CLASS) ? outer :
1441 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1442 Type.noType;
1443 } while (t.tag == CLASS);
1444 return null;
1445 case ARRAY:
1446 return isSubtype(t, sym.type) ? sym.type : null;
1447 case TYPEVAR:
1448 return asSuper(t, sym);
1449 case ERROR:
1450 return t;
1451 default:
1452 return null;
1453 }
1454 }
1455 // </editor-fold>
1457 // <editor-fold defaultstate="collapsed" desc="memberType">
1458 /**
1459 * The type of given symbol, seen as a member of t.
1460 *
1461 * @param t a type
1462 * @param sym a symbol
1463 */
1464 public Type memberType(Type t, Symbol sym) {
1465 return (sym.flags() & STATIC) != 0
1466 ? sym.type
1467 : memberType.visit(t, sym);
1468 }
1469 // where
1470 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1472 public Type visitType(Type t, Symbol sym) {
1473 return sym.type;
1474 }
1476 @Override
1477 public Type visitWildcardType(WildcardType t, Symbol sym) {
1478 return memberType(upperBound(t), sym);
1479 }
1481 @Override
1482 public Type visitClassType(ClassType t, Symbol sym) {
1483 Symbol owner = sym.owner;
1484 long flags = sym.flags();
1485 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1486 Type base = asOuterSuper(t, owner);
1487 //if t is an intersection type T = CT & I1 & I2 ... & In
1488 //its supertypes CT, I1, ... In might contain wildcards
1489 //so we need to go through capture conversion
1490 base = t.isCompound() ? capture(base) : base;
1491 if (base != null) {
1492 List<Type> ownerParams = owner.type.allparams();
1493 List<Type> baseParams = base.allparams();
1494 if (ownerParams.nonEmpty()) {
1495 if (baseParams.isEmpty()) {
1496 // then base is a raw type
1497 return erasure(sym.type);
1498 } else {
1499 return subst(sym.type, ownerParams, baseParams);
1500 }
1501 }
1502 }
1503 }
1504 return sym.type;
1505 }
1507 @Override
1508 public Type visitTypeVar(TypeVar t, Symbol sym) {
1509 return memberType(t.bound, sym);
1510 }
1512 @Override
1513 public Type visitErrorType(ErrorType t, Symbol sym) {
1514 return t;
1515 }
1516 };
1517 // </editor-fold>
1519 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1520 public boolean isAssignable(Type t, Type s) {
1521 return isAssignable(t, s, Warner.noWarnings);
1522 }
1524 /**
1525 * Is t assignable to s?<br>
1526 * Equivalent to subtype except for constant values and raw
1527 * types.<br>
1528 * (not defined for Method and ForAll types)
1529 */
1530 public boolean isAssignable(Type t, Type s, Warner warn) {
1531 if (t.tag == ERROR)
1532 return true;
1533 if (t.tag <= INT && t.constValue() != null) {
1534 int value = ((Number)t.constValue()).intValue();
1535 switch (s.tag) {
1536 case BYTE:
1537 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1538 return true;
1539 break;
1540 case CHAR:
1541 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1542 return true;
1543 break;
1544 case SHORT:
1545 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1546 return true;
1547 break;
1548 case INT:
1549 return true;
1550 case CLASS:
1551 switch (unboxedType(s).tag) {
1552 case BYTE:
1553 case CHAR:
1554 case SHORT:
1555 return isAssignable(t, unboxedType(s), warn);
1556 }
1557 break;
1558 }
1559 }
1560 return isConvertible(t, s, warn);
1561 }
1562 // </editor-fold>
1564 // <editor-fold defaultstate="collapsed" desc="erasure">
1565 /**
1566 * The erasure of t {@code |t|} -- the type that results when all
1567 * type parameters in t are deleted.
1568 */
1569 public Type erasure(Type t) {
1570 return erasure(t, false);
1571 }
1572 //where
1573 private Type erasure(Type t, boolean recurse) {
1574 if (t.tag <= lastBaseTag)
1575 return t; /* fast special case */
1576 else
1577 return erasure.visit(t, recurse);
1578 }
1579 // where
1580 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
1581 public Type visitType(Type t, Boolean recurse) {
1582 if (t.tag <= lastBaseTag)
1583 return t; /*fast special case*/
1584 else
1585 return t.map(recurse ? erasureRecFun : erasureFun);
1586 }
1588 @Override
1589 public Type visitWildcardType(WildcardType t, Boolean recurse) {
1590 return erasure(upperBound(t), recurse);
1591 }
1593 @Override
1594 public Type visitClassType(ClassType t, Boolean recurse) {
1595 Type erased = t.tsym.erasure(Types.this);
1596 if (recurse) {
1597 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
1598 }
1599 return erased;
1600 }
1602 @Override
1603 public Type visitTypeVar(TypeVar t, Boolean recurse) {
1604 return erasure(t.bound, recurse);
1605 }
1607 @Override
1608 public Type visitErrorType(ErrorType t, Boolean recurse) {
1609 return t;
1610 }
1611 };
1613 private Mapping erasureFun = new Mapping ("erasure") {
1614 public Type apply(Type t) { return erasure(t); }
1615 };
1617 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
1618 public Type apply(Type t) { return erasureRecursive(t); }
1619 };
1621 public List<Type> erasure(List<Type> ts) {
1622 return Type.map(ts, erasureFun);
1623 }
1625 public Type erasureRecursive(Type t) {
1626 return erasure(t, true);
1627 }
1629 public List<Type> erasureRecursive(List<Type> ts) {
1630 return Type.map(ts, erasureRecFun);
1631 }
1632 // </editor-fold>
1634 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
1635 /**
1636 * Make a compound type from non-empty list of types
1637 *
1638 * @param bounds the types from which the compound type is formed
1639 * @param supertype is objectType if all bounds are interfaces,
1640 * null otherwise.
1641 */
1642 public Type makeCompoundType(List<Type> bounds,
1643 Type supertype) {
1644 ClassSymbol bc =
1645 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
1646 Type.moreInfo
1647 ? names.fromString(bounds.toString())
1648 : names.empty,
1649 syms.noSymbol);
1650 if (bounds.head.tag == TYPEVAR)
1651 // error condition, recover
1652 bc.erasure_field = syms.objectType;
1653 else
1654 bc.erasure_field = erasure(bounds.head);
1655 bc.members_field = new Scope(bc);
1656 ClassType bt = (ClassType)bc.type;
1657 bt.allparams_field = List.nil();
1658 if (supertype != null) {
1659 bt.supertype_field = supertype;
1660 bt.interfaces_field = bounds;
1661 } else {
1662 bt.supertype_field = bounds.head;
1663 bt.interfaces_field = bounds.tail;
1664 }
1665 assert bt.supertype_field.tsym.completer != null
1666 || !bt.supertype_field.isInterface()
1667 : bt.supertype_field;
1668 return bt;
1669 }
1671 /**
1672 * Same as {@link #makeCompoundType(List,Type)}, except that the
1673 * second parameter is computed directly. Note that this might
1674 * cause a symbol completion. Hence, this version of
1675 * makeCompoundType may not be called during a classfile read.
1676 */
1677 public Type makeCompoundType(List<Type> bounds) {
1678 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1679 supertype(bounds.head) : null;
1680 return makeCompoundType(bounds, supertype);
1681 }
1683 /**
1684 * A convenience wrapper for {@link #makeCompoundType(List)}; the
1685 * arguments are converted to a list and passed to the other
1686 * method. Note that this might cause a symbol completion.
1687 * Hence, this version of makeCompoundType may not be called
1688 * during a classfile read.
1689 */
1690 public Type makeCompoundType(Type bound1, Type bound2) {
1691 return makeCompoundType(List.of(bound1, bound2));
1692 }
1693 // </editor-fold>
1695 // <editor-fold defaultstate="collapsed" desc="supertype">
1696 public Type supertype(Type t) {
1697 return supertype.visit(t);
1698 }
1699 // where
1700 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
1702 public Type visitType(Type t, Void ignored) {
1703 // A note on wildcards: there is no good way to
1704 // determine a supertype for a super bounded wildcard.
1705 return null;
1706 }
1708 @Override
1709 public Type visitClassType(ClassType t, Void ignored) {
1710 if (t.supertype_field == null) {
1711 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
1712 // An interface has no superclass; its supertype is Object.
1713 if (t.isInterface())
1714 supertype = ((ClassType)t.tsym.type).supertype_field;
1715 if (t.supertype_field == null) {
1716 List<Type> actuals = classBound(t).allparams();
1717 List<Type> formals = t.tsym.type.allparams();
1718 if (t.hasErasedSupertypes()) {
1719 t.supertype_field = erasureRecursive(supertype);
1720 } else if (formals.nonEmpty()) {
1721 t.supertype_field = subst(supertype, formals, actuals);
1722 }
1723 else {
1724 t.supertype_field = supertype;
1725 }
1726 }
1727 }
1728 return t.supertype_field;
1729 }
1731 /**
1732 * The supertype is always a class type. If the type
1733 * variable's bounds start with a class type, this is also
1734 * the supertype. Otherwise, the supertype is
1735 * java.lang.Object.
1736 */
1737 @Override
1738 public Type visitTypeVar(TypeVar t, Void ignored) {
1739 if (t.bound.tag == TYPEVAR ||
1740 (!t.bound.isCompound() && !t.bound.isInterface())) {
1741 return t.bound;
1742 } else {
1743 return supertype(t.bound);
1744 }
1745 }
1747 @Override
1748 public Type visitArrayType(ArrayType t, Void ignored) {
1749 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
1750 return arraySuperType();
1751 else
1752 return new ArrayType(supertype(t.elemtype), t.tsym);
1753 }
1755 @Override
1756 public Type visitErrorType(ErrorType t, Void ignored) {
1757 return t;
1758 }
1759 };
1760 // </editor-fold>
1762 // <editor-fold defaultstate="collapsed" desc="interfaces">
1763 /**
1764 * Return the interfaces implemented by this class.
1765 */
1766 public List<Type> interfaces(Type t) {
1767 return interfaces.visit(t);
1768 }
1769 // where
1770 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
1772 public List<Type> visitType(Type t, Void ignored) {
1773 return List.nil();
1774 }
1776 @Override
1777 public List<Type> visitClassType(ClassType t, Void ignored) {
1778 if (t.interfaces_field == null) {
1779 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
1780 if (t.interfaces_field == null) {
1781 // If t.interfaces_field is null, then t must
1782 // be a parameterized type (not to be confused
1783 // with a generic type declaration).
1784 // Terminology:
1785 // Parameterized type: List<String>
1786 // Generic type declaration: class List<E> { ... }
1787 // So t corresponds to List<String> and
1788 // t.tsym.type corresponds to List<E>.
1789 // The reason t must be parameterized type is
1790 // that completion will happen as a side
1791 // effect of calling
1792 // ClassSymbol.getInterfaces. Since
1793 // t.interfaces_field is null after
1794 // completion, we can assume that t is not the
1795 // type of a class/interface declaration.
1796 assert t != t.tsym.type : t.toString();
1797 List<Type> actuals = t.allparams();
1798 List<Type> formals = t.tsym.type.allparams();
1799 if (t.hasErasedSupertypes()) {
1800 t.interfaces_field = erasureRecursive(interfaces);
1801 } else if (formals.nonEmpty()) {
1802 t.interfaces_field =
1803 upperBounds(subst(interfaces, formals, actuals));
1804 }
1805 else {
1806 t.interfaces_field = interfaces;
1807 }
1808 }
1809 }
1810 return t.interfaces_field;
1811 }
1813 @Override
1814 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
1815 if (t.bound.isCompound())
1816 return interfaces(t.bound);
1818 if (t.bound.isInterface())
1819 return List.of(t.bound);
1821 return List.nil();
1822 }
1823 };
1824 // </editor-fold>
1826 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
1827 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
1829 public boolean isDerivedRaw(Type t) {
1830 Boolean result = isDerivedRawCache.get(t);
1831 if (result == null) {
1832 result = isDerivedRawInternal(t);
1833 isDerivedRawCache.put(t, result);
1834 }
1835 return result;
1836 }
1838 public boolean isDerivedRawInternal(Type t) {
1839 if (t.isErroneous())
1840 return false;
1841 return
1842 t.isRaw() ||
1843 supertype(t) != null && isDerivedRaw(supertype(t)) ||
1844 isDerivedRaw(interfaces(t));
1845 }
1847 public boolean isDerivedRaw(List<Type> ts) {
1848 List<Type> l = ts;
1849 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
1850 return l.nonEmpty();
1851 }
1852 // </editor-fold>
1854 // <editor-fold defaultstate="collapsed" desc="setBounds">
1855 /**
1856 * Set the bounds field of the given type variable to reflect a
1857 * (possibly multiple) list of bounds.
1858 * @param t a type variable
1859 * @param bounds the bounds, must be nonempty
1860 * @param supertype is objectType if all bounds are interfaces,
1861 * null otherwise.
1862 */
1863 public void setBounds(TypeVar t, List<Type> bounds, Type supertype) {
1864 if (bounds.tail.isEmpty())
1865 t.bound = bounds.head;
1866 else
1867 t.bound = makeCompoundType(bounds, supertype);
1868 t.rank_field = -1;
1869 }
1871 /**
1872 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
1873 * third parameter is computed directly, as follows: if all
1874 * all bounds are interface types, the computed supertype is Object,
1875 * otherwise the supertype is simply left null (in this case, the supertype
1876 * is assumed to be the head of the bound list passed as second argument).
1877 * Note that this check might cause a symbol completion. Hence, this version of
1878 * setBounds may not be called during a classfile read.
1879 */
1880 public void setBounds(TypeVar t, List<Type> bounds) {
1881 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1882 syms.objectType : null;
1883 setBounds(t, bounds, supertype);
1884 t.rank_field = -1;
1885 }
1886 // </editor-fold>
1888 // <editor-fold defaultstate="collapsed" desc="getBounds">
1889 /**
1890 * Return list of bounds of the given type variable.
1891 */
1892 public List<Type> getBounds(TypeVar t) {
1893 if (t.bound.isErroneous() || !t.bound.isCompound())
1894 return List.of(t.bound);
1895 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
1896 return interfaces(t).prepend(supertype(t));
1897 else
1898 // No superclass was given in bounds.
1899 // In this case, supertype is Object, erasure is first interface.
1900 return interfaces(t);
1901 }
1902 // </editor-fold>
1904 // <editor-fold defaultstate="collapsed" desc="classBound">
1905 /**
1906 * If the given type is a (possibly selected) type variable,
1907 * return the bounding class of this type, otherwise return the
1908 * type itself.
1909 */
1910 public Type classBound(Type t) {
1911 return classBound.visit(t);
1912 }
1913 // where
1914 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
1916 public Type visitType(Type t, Void ignored) {
1917 return t;
1918 }
1920 @Override
1921 public Type visitClassType(ClassType t, Void ignored) {
1922 Type outer1 = classBound(t.getEnclosingType());
1923 if (outer1 != t.getEnclosingType())
1924 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
1925 else
1926 return t;
1927 }
1929 @Override
1930 public Type visitTypeVar(TypeVar t, Void ignored) {
1931 return classBound(supertype(t));
1932 }
1934 @Override
1935 public Type visitErrorType(ErrorType t, Void ignored) {
1936 return t;
1937 }
1938 };
1939 // </editor-fold>
1941 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
1942 /**
1943 * Returns true iff the first signature is a <em>sub
1944 * signature</em> of the other. This is <b>not</b> an equivalence
1945 * relation.
1946 *
1947 * @see "The Java Language Specification, Third Ed. (8.4.2)."
1948 * @see #overrideEquivalent(Type t, Type s)
1949 * @param t first signature (possibly raw).
1950 * @param s second signature (could be subjected to erasure).
1951 * @return true if t is a sub signature of s.
1952 */
1953 public boolean isSubSignature(Type t, Type s) {
1954 return hasSameArgs(t, s) || hasSameArgs(t, erasure(s));
1955 }
1957 /**
1958 * Returns true iff these signatures are related by <em>override
1959 * equivalence</em>. This is the natural extension of
1960 * isSubSignature to an equivalence relation.
1961 *
1962 * @see "The Java Language Specification, Third Ed. (8.4.2)."
1963 * @see #isSubSignature(Type t, Type s)
1964 * @param t a signature (possible raw, could be subjected to
1965 * erasure).
1966 * @param s a signature (possible raw, could be subjected to
1967 * erasure).
1968 * @return true if either argument is a sub signature of the other.
1969 */
1970 public boolean overrideEquivalent(Type t, Type s) {
1971 return hasSameArgs(t, s) ||
1972 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
1973 }
1975 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
1976 class ImplementationCache {
1978 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
1979 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
1981 class Entry {
1982 final MethodSymbol cachedImpl;
1983 final Filter<Symbol> implFilter;
1984 final boolean checkResult;
1985 final Scope.ScopeCounter scopeCounter;
1987 public Entry(MethodSymbol cachedImpl,
1988 Filter<Symbol> scopeFilter,
1989 boolean checkResult,
1990 Scope.ScopeCounter scopeCounter) {
1991 this.cachedImpl = cachedImpl;
1992 this.implFilter = scopeFilter;
1993 this.checkResult = checkResult;
1994 this.scopeCounter = scopeCounter;
1995 }
1997 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, Scope.ScopeCounter scopeCounter) {
1998 return this.implFilter == scopeFilter &&
1999 this.checkResult == checkResult &&
2000 this.scopeCounter.val() >= scopeCounter.val();
2001 }
2002 }
2004 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter, Scope.ScopeCounter scopeCounter) {
2005 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2006 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2007 if (cache == null) {
2008 cache = new HashMap<TypeSymbol, Entry>();
2009 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2010 }
2011 Entry e = cache.get(origin);
2012 if (e == null ||
2013 !e.matches(implFilter, checkResult, scopeCounter)) {
2014 MethodSymbol impl = implementationInternal(ms, origin, Types.this, checkResult, implFilter);
2015 cache.put(origin, new Entry(impl, implFilter, checkResult, scopeCounter));
2016 return impl;
2017 }
2018 else {
2019 return e.cachedImpl;
2020 }
2021 }
2023 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, Types types, boolean checkResult, Filter<Symbol> implFilter) {
2024 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = types.supertype(t)) {
2025 while (t.tag == TYPEVAR)
2026 t = t.getUpperBound();
2027 TypeSymbol c = t.tsym;
2028 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2029 e.scope != null;
2030 e = e.next(implFilter)) {
2031 if (e.sym != null &&
2032 e.sym.overrides(ms, origin, types, checkResult))
2033 return (MethodSymbol)e.sym;
2034 }
2035 }
2036 return null;
2037 }
2038 }
2040 private ImplementationCache implCache = new ImplementationCache();
2042 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, Types types, boolean checkResult, Filter<Symbol> implFilter) {
2043 return implCache.get(ms, origin, checkResult, implFilter, scopeCounter);
2044 }
2045 // </editor-fold>
2047 /**
2048 * Does t have the same arguments as s? It is assumed that both
2049 * types are (possibly polymorphic) method types. Monomorphic
2050 * method types "have the same arguments", if their argument lists
2051 * are equal. Polymorphic method types "have the same arguments",
2052 * if they have the same arguments after renaming all type
2053 * variables of one to corresponding type variables in the other,
2054 * where correspondence is by position in the type parameter list.
2055 */
2056 public boolean hasSameArgs(Type t, Type s) {
2057 return hasSameArgs.visit(t, s);
2058 }
2059 // where
2060 private TypeRelation hasSameArgs = new TypeRelation() {
2062 public Boolean visitType(Type t, Type s) {
2063 throw new AssertionError();
2064 }
2066 @Override
2067 public Boolean visitMethodType(MethodType t, Type s) {
2068 return s.tag == METHOD
2069 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2070 }
2072 @Override
2073 public Boolean visitForAll(ForAll t, Type s) {
2074 if (s.tag != FORALL)
2075 return false;
2077 ForAll forAll = (ForAll)s;
2078 return hasSameBounds(t, forAll)
2079 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2080 }
2082 @Override
2083 public Boolean visitErrorType(ErrorType t, Type s) {
2084 return false;
2085 }
2086 };
2087 // </editor-fold>
2089 // <editor-fold defaultstate="collapsed" desc="subst">
2090 public List<Type> subst(List<Type> ts,
2091 List<Type> from,
2092 List<Type> to) {
2093 return new Subst(from, to).subst(ts);
2094 }
2096 /**
2097 * Substitute all occurrences of a type in `from' with the
2098 * corresponding type in `to' in 't'. Match lists `from' and `to'
2099 * from the right: If lists have different length, discard leading
2100 * elements of the longer list.
2101 */
2102 public Type subst(Type t, List<Type> from, List<Type> to) {
2103 return new Subst(from, to).subst(t);
2104 }
2106 private class Subst extends UnaryVisitor<Type> {
2107 List<Type> from;
2108 List<Type> to;
2110 public Subst(List<Type> from, List<Type> to) {
2111 int fromLength = from.length();
2112 int toLength = to.length();
2113 while (fromLength > toLength) {
2114 fromLength--;
2115 from = from.tail;
2116 }
2117 while (fromLength < toLength) {
2118 toLength--;
2119 to = to.tail;
2120 }
2121 this.from = from;
2122 this.to = to;
2123 }
2125 Type subst(Type t) {
2126 if (from.tail == null)
2127 return t;
2128 else
2129 return visit(t);
2130 }
2132 List<Type> subst(List<Type> ts) {
2133 if (from.tail == null)
2134 return ts;
2135 boolean wild = false;
2136 if (ts.nonEmpty() && from.nonEmpty()) {
2137 Type head1 = subst(ts.head);
2138 List<Type> tail1 = subst(ts.tail);
2139 if (head1 != ts.head || tail1 != ts.tail)
2140 return tail1.prepend(head1);
2141 }
2142 return ts;
2143 }
2145 public Type visitType(Type t, Void ignored) {
2146 return t;
2147 }
2149 @Override
2150 public Type visitMethodType(MethodType t, Void ignored) {
2151 List<Type> argtypes = subst(t.argtypes);
2152 Type restype = subst(t.restype);
2153 List<Type> thrown = subst(t.thrown);
2154 if (argtypes == t.argtypes &&
2155 restype == t.restype &&
2156 thrown == t.thrown)
2157 return t;
2158 else
2159 return new MethodType(argtypes, restype, thrown, t.tsym);
2160 }
2162 @Override
2163 public Type visitTypeVar(TypeVar t, Void ignored) {
2164 for (List<Type> from = this.from, to = this.to;
2165 from.nonEmpty();
2166 from = from.tail, to = to.tail) {
2167 if (t == from.head) {
2168 return to.head.withTypeVar(t);
2169 }
2170 }
2171 return t;
2172 }
2174 @Override
2175 public Type visitClassType(ClassType t, Void ignored) {
2176 if (!t.isCompound()) {
2177 List<Type> typarams = t.getTypeArguments();
2178 List<Type> typarams1 = subst(typarams);
2179 Type outer = t.getEnclosingType();
2180 Type outer1 = subst(outer);
2181 if (typarams1 == typarams && outer1 == outer)
2182 return t;
2183 else
2184 return new ClassType(outer1, typarams1, t.tsym);
2185 } else {
2186 Type st = subst(supertype(t));
2187 List<Type> is = upperBounds(subst(interfaces(t)));
2188 if (st == supertype(t) && is == interfaces(t))
2189 return t;
2190 else
2191 return makeCompoundType(is.prepend(st));
2192 }
2193 }
2195 @Override
2196 public Type visitWildcardType(WildcardType t, Void ignored) {
2197 Type bound = t.type;
2198 if (t.kind != BoundKind.UNBOUND)
2199 bound = subst(bound);
2200 if (bound == t.type) {
2201 return t;
2202 } else {
2203 if (t.isExtendsBound() && bound.isExtendsBound())
2204 bound = upperBound(bound);
2205 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2206 }
2207 }
2209 @Override
2210 public Type visitArrayType(ArrayType t, Void ignored) {
2211 Type elemtype = subst(t.elemtype);
2212 if (elemtype == t.elemtype)
2213 return t;
2214 else
2215 return new ArrayType(upperBound(elemtype), t.tsym);
2216 }
2218 @Override
2219 public Type visitForAll(ForAll t, Void ignored) {
2220 List<Type> tvars1 = substBounds(t.tvars, from, to);
2221 Type qtype1 = subst(t.qtype);
2222 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2223 return t;
2224 } else if (tvars1 == t.tvars) {
2225 return new ForAll(tvars1, qtype1);
2226 } else {
2227 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2228 }
2229 }
2231 @Override
2232 public Type visitErrorType(ErrorType t, Void ignored) {
2233 return t;
2234 }
2235 }
2237 public List<Type> substBounds(List<Type> tvars,
2238 List<Type> from,
2239 List<Type> to) {
2240 if (tvars.isEmpty())
2241 return tvars;
2242 ListBuffer<Type> newBoundsBuf = lb();
2243 boolean changed = false;
2244 // calculate new bounds
2245 for (Type t : tvars) {
2246 TypeVar tv = (TypeVar) t;
2247 Type bound = subst(tv.bound, from, to);
2248 if (bound != tv.bound)
2249 changed = true;
2250 newBoundsBuf.append(bound);
2251 }
2252 if (!changed)
2253 return tvars;
2254 ListBuffer<Type> newTvars = lb();
2255 // create new type variables without bounds
2256 for (Type t : tvars) {
2257 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2258 }
2259 // the new bounds should use the new type variables in place
2260 // of the old
2261 List<Type> newBounds = newBoundsBuf.toList();
2262 from = tvars;
2263 to = newTvars.toList();
2264 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2265 newBounds.head = subst(newBounds.head, from, to);
2266 }
2267 newBounds = newBoundsBuf.toList();
2268 // set the bounds of new type variables to the new bounds
2269 for (Type t : newTvars.toList()) {
2270 TypeVar tv = (TypeVar) t;
2271 tv.bound = newBounds.head;
2272 newBounds = newBounds.tail;
2273 }
2274 return newTvars.toList();
2275 }
2277 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2278 Type bound1 = subst(t.bound, from, to);
2279 if (bound1 == t.bound)
2280 return t;
2281 else {
2282 // create new type variable without bounds
2283 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2284 // the new bound should use the new type variable in place
2285 // of the old
2286 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2287 return tv;
2288 }
2289 }
2290 // </editor-fold>
2292 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2293 /**
2294 * Does t have the same bounds for quantified variables as s?
2295 */
2296 boolean hasSameBounds(ForAll t, ForAll s) {
2297 List<Type> l1 = t.tvars;
2298 List<Type> l2 = s.tvars;
2299 while (l1.nonEmpty() && l2.nonEmpty() &&
2300 isSameType(l1.head.getUpperBound(),
2301 subst(l2.head.getUpperBound(),
2302 s.tvars,
2303 t.tvars))) {
2304 l1 = l1.tail;
2305 l2 = l2.tail;
2306 }
2307 return l1.isEmpty() && l2.isEmpty();
2308 }
2309 // </editor-fold>
2311 // <editor-fold defaultstate="collapsed" desc="newInstances">
2312 /** Create new vector of type variables from list of variables
2313 * changing all recursive bounds from old to new list.
2314 */
2315 public List<Type> newInstances(List<Type> tvars) {
2316 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2317 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2318 TypeVar tv = (TypeVar) l.head;
2319 tv.bound = subst(tv.bound, tvars, tvars1);
2320 }
2321 return tvars1;
2322 }
2323 static private Mapping newInstanceFun = new Mapping("newInstanceFun") {
2324 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2325 };
2326 // </editor-fold>
2328 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2329 public Type createErrorType(Type originalType) {
2330 return new ErrorType(originalType, syms.errSymbol);
2331 }
2333 public Type createErrorType(ClassSymbol c, Type originalType) {
2334 return new ErrorType(c, originalType);
2335 }
2337 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
2338 return new ErrorType(name, container, originalType);
2339 }
2340 // </editor-fold>
2342 // <editor-fold defaultstate="collapsed" desc="rank">
2343 /**
2344 * The rank of a class is the length of the longest path between
2345 * the class and java.lang.Object in the class inheritance
2346 * graph. Undefined for all but reference types.
2347 */
2348 public int rank(Type t) {
2349 switch(t.tag) {
2350 case CLASS: {
2351 ClassType cls = (ClassType)t;
2352 if (cls.rank_field < 0) {
2353 Name fullname = cls.tsym.getQualifiedName();
2354 if (fullname == names.java_lang_Object)
2355 cls.rank_field = 0;
2356 else {
2357 int r = rank(supertype(cls));
2358 for (List<Type> l = interfaces(cls);
2359 l.nonEmpty();
2360 l = l.tail) {
2361 if (rank(l.head) > r)
2362 r = rank(l.head);
2363 }
2364 cls.rank_field = r + 1;
2365 }
2366 }
2367 return cls.rank_field;
2368 }
2369 case TYPEVAR: {
2370 TypeVar tvar = (TypeVar)t;
2371 if (tvar.rank_field < 0) {
2372 int r = rank(supertype(tvar));
2373 for (List<Type> l = interfaces(tvar);
2374 l.nonEmpty();
2375 l = l.tail) {
2376 if (rank(l.head) > r) r = rank(l.head);
2377 }
2378 tvar.rank_field = r + 1;
2379 }
2380 return tvar.rank_field;
2381 }
2382 case ERROR:
2383 return 0;
2384 default:
2385 throw new AssertionError();
2386 }
2387 }
2388 // </editor-fold>
2390 /**
2391 * Helper method for generating a string representation of a given type
2392 * accordingly to a given locale
2393 */
2394 public String toString(Type t, Locale locale) {
2395 return Printer.createStandardPrinter(messages).visit(t, locale);
2396 }
2398 /**
2399 * Helper method for generating a string representation of a given type
2400 * accordingly to a given locale
2401 */
2402 public String toString(Symbol t, Locale locale) {
2403 return Printer.createStandardPrinter(messages).visit(t, locale);
2404 }
2406 // <editor-fold defaultstate="collapsed" desc="toString">
2407 /**
2408 * This toString is slightly more descriptive than the one on Type.
2409 *
2410 * @deprecated Types.toString(Type t, Locale l) provides better support
2411 * for localization
2412 */
2413 @Deprecated
2414 public String toString(Type t) {
2415 if (t.tag == FORALL) {
2416 ForAll forAll = (ForAll)t;
2417 return typaramsString(forAll.tvars) + forAll.qtype;
2418 }
2419 return "" + t;
2420 }
2421 // where
2422 private String typaramsString(List<Type> tvars) {
2423 StringBuffer s = new StringBuffer();
2424 s.append('<');
2425 boolean first = true;
2426 for (Type t : tvars) {
2427 if (!first) s.append(", ");
2428 first = false;
2429 appendTyparamString(((TypeVar)t), s);
2430 }
2431 s.append('>');
2432 return s.toString();
2433 }
2434 private void appendTyparamString(TypeVar t, StringBuffer buf) {
2435 buf.append(t);
2436 if (t.bound == null ||
2437 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
2438 return;
2439 buf.append(" extends "); // Java syntax; no need for i18n
2440 Type bound = t.bound;
2441 if (!bound.isCompound()) {
2442 buf.append(bound);
2443 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
2444 buf.append(supertype(t));
2445 for (Type intf : interfaces(t)) {
2446 buf.append('&');
2447 buf.append(intf);
2448 }
2449 } else {
2450 // No superclass was given in bounds.
2451 // In this case, supertype is Object, erasure is first interface.
2452 boolean first = true;
2453 for (Type intf : interfaces(t)) {
2454 if (!first) buf.append('&');
2455 first = false;
2456 buf.append(intf);
2457 }
2458 }
2459 }
2460 // </editor-fold>
2462 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
2463 /**
2464 * A cache for closures.
2465 *
2466 * <p>A closure is a list of all the supertypes and interfaces of
2467 * a class or interface type, ordered by ClassSymbol.precedes
2468 * (that is, subclasses come first, arbitrary but fixed
2469 * otherwise).
2470 */
2471 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
2473 /**
2474 * Returns the closure of a class or interface type.
2475 */
2476 public List<Type> closure(Type t) {
2477 List<Type> cl = closureCache.get(t);
2478 if (cl == null) {
2479 Type st = supertype(t);
2480 if (!t.isCompound()) {
2481 if (st.tag == CLASS) {
2482 cl = insert(closure(st), t);
2483 } else if (st.tag == TYPEVAR) {
2484 cl = closure(st).prepend(t);
2485 } else {
2486 cl = List.of(t);
2487 }
2488 } else {
2489 cl = closure(supertype(t));
2490 }
2491 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
2492 cl = union(cl, closure(l.head));
2493 closureCache.put(t, cl);
2494 }
2495 return cl;
2496 }
2498 /**
2499 * Insert a type in a closure
2500 */
2501 public List<Type> insert(List<Type> cl, Type t) {
2502 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
2503 return cl.prepend(t);
2504 } else if (cl.head.tsym.precedes(t.tsym, this)) {
2505 return insert(cl.tail, t).prepend(cl.head);
2506 } else {
2507 return cl;
2508 }
2509 }
2511 /**
2512 * Form the union of two closures
2513 */
2514 public List<Type> union(List<Type> cl1, List<Type> cl2) {
2515 if (cl1.isEmpty()) {
2516 return cl2;
2517 } else if (cl2.isEmpty()) {
2518 return cl1;
2519 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
2520 return union(cl1.tail, cl2).prepend(cl1.head);
2521 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
2522 return union(cl1, cl2.tail).prepend(cl2.head);
2523 } else {
2524 return union(cl1.tail, cl2.tail).prepend(cl1.head);
2525 }
2526 }
2528 /**
2529 * Intersect two closures
2530 */
2531 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
2532 if (cl1 == cl2)
2533 return cl1;
2534 if (cl1.isEmpty() || cl2.isEmpty())
2535 return List.nil();
2536 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
2537 return intersect(cl1.tail, cl2);
2538 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
2539 return intersect(cl1, cl2.tail);
2540 if (isSameType(cl1.head, cl2.head))
2541 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
2542 if (cl1.head.tsym == cl2.head.tsym &&
2543 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
2544 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
2545 Type merge = merge(cl1.head,cl2.head);
2546 return intersect(cl1.tail, cl2.tail).prepend(merge);
2547 }
2548 if (cl1.head.isRaw() || cl2.head.isRaw())
2549 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
2550 }
2551 return intersect(cl1.tail, cl2.tail);
2552 }
2553 // where
2554 class TypePair {
2555 final Type t1;
2556 final Type t2;
2557 TypePair(Type t1, Type t2) {
2558 this.t1 = t1;
2559 this.t2 = t2;
2560 }
2561 @Override
2562 public int hashCode() {
2563 return 127 * Types.hashCode(t1) + Types.hashCode(t2);
2564 }
2565 @Override
2566 public boolean equals(Object obj) {
2567 if (!(obj instanceof TypePair))
2568 return false;
2569 TypePair typePair = (TypePair)obj;
2570 return isSameType(t1, typePair.t1)
2571 && isSameType(t2, typePair.t2);
2572 }
2573 }
2574 Set<TypePair> mergeCache = new HashSet<TypePair>();
2575 private Type merge(Type c1, Type c2) {
2576 ClassType class1 = (ClassType) c1;
2577 List<Type> act1 = class1.getTypeArguments();
2578 ClassType class2 = (ClassType) c2;
2579 List<Type> act2 = class2.getTypeArguments();
2580 ListBuffer<Type> merged = new ListBuffer<Type>();
2581 List<Type> typarams = class1.tsym.type.getTypeArguments();
2583 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
2584 if (containsType(act1.head, act2.head)) {
2585 merged.append(act1.head);
2586 } else if (containsType(act2.head, act1.head)) {
2587 merged.append(act2.head);
2588 } else {
2589 TypePair pair = new TypePair(c1, c2);
2590 Type m;
2591 if (mergeCache.add(pair)) {
2592 m = new WildcardType(lub(upperBound(act1.head),
2593 upperBound(act2.head)),
2594 BoundKind.EXTENDS,
2595 syms.boundClass);
2596 mergeCache.remove(pair);
2597 } else {
2598 m = new WildcardType(syms.objectType,
2599 BoundKind.UNBOUND,
2600 syms.boundClass);
2601 }
2602 merged.append(m.withTypeVar(typarams.head));
2603 }
2604 act1 = act1.tail;
2605 act2 = act2.tail;
2606 typarams = typarams.tail;
2607 }
2608 assert(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
2609 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
2610 }
2612 /**
2613 * Return the minimum type of a closure, a compound type if no
2614 * unique minimum exists.
2615 */
2616 private Type compoundMin(List<Type> cl) {
2617 if (cl.isEmpty()) return syms.objectType;
2618 List<Type> compound = closureMin(cl);
2619 if (compound.isEmpty())
2620 return null;
2621 else if (compound.tail.isEmpty())
2622 return compound.head;
2623 else
2624 return makeCompoundType(compound);
2625 }
2627 /**
2628 * Return the minimum types of a closure, suitable for computing
2629 * compoundMin or glb.
2630 */
2631 private List<Type> closureMin(List<Type> cl) {
2632 ListBuffer<Type> classes = lb();
2633 ListBuffer<Type> interfaces = lb();
2634 while (!cl.isEmpty()) {
2635 Type current = cl.head;
2636 if (current.isInterface())
2637 interfaces.append(current);
2638 else
2639 classes.append(current);
2640 ListBuffer<Type> candidates = lb();
2641 for (Type t : cl.tail) {
2642 if (!isSubtypeNoCapture(current, t))
2643 candidates.append(t);
2644 }
2645 cl = candidates.toList();
2646 }
2647 return classes.appendList(interfaces).toList();
2648 }
2650 /**
2651 * Return the least upper bound of pair of types. if the lub does
2652 * not exist return null.
2653 */
2654 public Type lub(Type t1, Type t2) {
2655 return lub(List.of(t1, t2));
2656 }
2658 /**
2659 * Return the least upper bound (lub) of set of types. If the lub
2660 * does not exist return the type of null (bottom).
2661 */
2662 public Type lub(List<Type> ts) {
2663 final int ARRAY_BOUND = 1;
2664 final int CLASS_BOUND = 2;
2665 int boundkind = 0;
2666 for (Type t : ts) {
2667 switch (t.tag) {
2668 case CLASS:
2669 boundkind |= CLASS_BOUND;
2670 break;
2671 case ARRAY:
2672 boundkind |= ARRAY_BOUND;
2673 break;
2674 case TYPEVAR:
2675 do {
2676 t = t.getUpperBound();
2677 } while (t.tag == TYPEVAR);
2678 if (t.tag == ARRAY) {
2679 boundkind |= ARRAY_BOUND;
2680 } else {
2681 boundkind |= CLASS_BOUND;
2682 }
2683 break;
2684 default:
2685 if (t.isPrimitive())
2686 return syms.errType;
2687 }
2688 }
2689 switch (boundkind) {
2690 case 0:
2691 return syms.botType;
2693 case ARRAY_BOUND:
2694 // calculate lub(A[], B[])
2695 List<Type> elements = Type.map(ts, elemTypeFun);
2696 for (Type t : elements) {
2697 if (t.isPrimitive()) {
2698 // if a primitive type is found, then return
2699 // arraySuperType unless all the types are the
2700 // same
2701 Type first = ts.head;
2702 for (Type s : ts.tail) {
2703 if (!isSameType(first, s)) {
2704 // lub(int[], B[]) is Cloneable & Serializable
2705 return arraySuperType();
2706 }
2707 }
2708 // all the array types are the same, return one
2709 // lub(int[], int[]) is int[]
2710 return first;
2711 }
2712 }
2713 // lub(A[], B[]) is lub(A, B)[]
2714 return new ArrayType(lub(elements), syms.arrayClass);
2716 case CLASS_BOUND:
2717 // calculate lub(A, B)
2718 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
2719 ts = ts.tail;
2720 assert !ts.isEmpty();
2721 List<Type> cl = closure(ts.head);
2722 for (Type t : ts.tail) {
2723 if (t.tag == CLASS || t.tag == TYPEVAR)
2724 cl = intersect(cl, closure(t));
2725 }
2726 return compoundMin(cl);
2728 default:
2729 // calculate lub(A, B[])
2730 List<Type> classes = List.of(arraySuperType());
2731 for (Type t : ts) {
2732 if (t.tag != ARRAY) // Filter out any arrays
2733 classes = classes.prepend(t);
2734 }
2735 // lub(A, B[]) is lub(A, arraySuperType)
2736 return lub(classes);
2737 }
2738 }
2739 // where
2740 private Type arraySuperType = null;
2741 private Type arraySuperType() {
2742 // initialized lazily to avoid problems during compiler startup
2743 if (arraySuperType == null) {
2744 synchronized (this) {
2745 if (arraySuperType == null) {
2746 // JLS 10.8: all arrays implement Cloneable and Serializable.
2747 arraySuperType = makeCompoundType(List.of(syms.serializableType,
2748 syms.cloneableType),
2749 syms.objectType);
2750 }
2751 }
2752 }
2753 return arraySuperType;
2754 }
2755 // </editor-fold>
2757 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
2758 public Type glb(List<Type> ts) {
2759 Type t1 = ts.head;
2760 for (Type t2 : ts.tail) {
2761 if (t1.isErroneous())
2762 return t1;
2763 t1 = glb(t1, t2);
2764 }
2765 return t1;
2766 }
2767 //where
2768 public Type glb(Type t, Type s) {
2769 if (s == null)
2770 return t;
2771 else if (t.isPrimitive() || s.isPrimitive())
2772 return syms.errType;
2773 else if (isSubtypeNoCapture(t, s))
2774 return t;
2775 else if (isSubtypeNoCapture(s, t))
2776 return s;
2778 List<Type> closure = union(closure(t), closure(s));
2779 List<Type> bounds = closureMin(closure);
2781 if (bounds.isEmpty()) { // length == 0
2782 return syms.objectType;
2783 } else if (bounds.tail.isEmpty()) { // length == 1
2784 return bounds.head;
2785 } else { // length > 1
2786 int classCount = 0;
2787 for (Type bound : bounds)
2788 if (!bound.isInterface())
2789 classCount++;
2790 if (classCount > 1)
2791 return createErrorType(t);
2792 }
2793 return makeCompoundType(bounds);
2794 }
2795 // </editor-fold>
2797 // <editor-fold defaultstate="collapsed" desc="hashCode">
2798 /**
2799 * Compute a hash code on a type.
2800 */
2801 public static int hashCode(Type t) {
2802 return hashCode.visit(t);
2803 }
2804 // where
2805 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
2807 public Integer visitType(Type t, Void ignored) {
2808 return t.tag;
2809 }
2811 @Override
2812 public Integer visitClassType(ClassType t, Void ignored) {
2813 int result = visit(t.getEnclosingType());
2814 result *= 127;
2815 result += t.tsym.flatName().hashCode();
2816 for (Type s : t.getTypeArguments()) {
2817 result *= 127;
2818 result += visit(s);
2819 }
2820 return result;
2821 }
2823 @Override
2824 public Integer visitWildcardType(WildcardType t, Void ignored) {
2825 int result = t.kind.hashCode();
2826 if (t.type != null) {
2827 result *= 127;
2828 result += visit(t.type);
2829 }
2830 return result;
2831 }
2833 @Override
2834 public Integer visitArrayType(ArrayType t, Void ignored) {
2835 return visit(t.elemtype) + 12;
2836 }
2838 @Override
2839 public Integer visitTypeVar(TypeVar t, Void ignored) {
2840 return System.identityHashCode(t.tsym);
2841 }
2843 @Override
2844 public Integer visitUndetVar(UndetVar t, Void ignored) {
2845 return System.identityHashCode(t);
2846 }
2848 @Override
2849 public Integer visitErrorType(ErrorType t, Void ignored) {
2850 return 0;
2851 }
2852 };
2853 // </editor-fold>
2855 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
2856 /**
2857 * Does t have a result that is a subtype of the result type of s,
2858 * suitable for covariant returns? It is assumed that both types
2859 * are (possibly polymorphic) method types. Monomorphic method
2860 * types are handled in the obvious way. Polymorphic method types
2861 * require renaming all type variables of one to corresponding
2862 * type variables in the other, where correspondence is by
2863 * position in the type parameter list. */
2864 public boolean resultSubtype(Type t, Type s, Warner warner) {
2865 List<Type> tvars = t.getTypeArguments();
2866 List<Type> svars = s.getTypeArguments();
2867 Type tres = t.getReturnType();
2868 Type sres = subst(s.getReturnType(), svars, tvars);
2869 return covariantReturnType(tres, sres, warner);
2870 }
2872 /**
2873 * Return-Type-Substitutable.
2874 * @see <a href="http://java.sun.com/docs/books/jls/">The Java
2875 * Language Specification, Third Ed. (8.4.5)</a>
2876 */
2877 public boolean returnTypeSubstitutable(Type r1, Type r2) {
2878 if (hasSameArgs(r1, r2))
2879 return resultSubtype(r1, r2, Warner.noWarnings);
2880 else
2881 return covariantReturnType(r1.getReturnType(),
2882 erasure(r2.getReturnType()),
2883 Warner.noWarnings);
2884 }
2886 public boolean returnTypeSubstitutable(Type r1,
2887 Type r2, Type r2res,
2888 Warner warner) {
2889 if (isSameType(r1.getReturnType(), r2res))
2890 return true;
2891 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
2892 return false;
2894 if (hasSameArgs(r1, r2))
2895 return covariantReturnType(r1.getReturnType(), r2res, warner);
2896 if (!source.allowCovariantReturns())
2897 return false;
2898 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
2899 return true;
2900 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
2901 return false;
2902 warner.warnUnchecked();
2903 return true;
2904 }
2906 /**
2907 * Is t an appropriate return type in an overrider for a
2908 * method that returns s?
2909 */
2910 public boolean covariantReturnType(Type t, Type s, Warner warner) {
2911 return
2912 isSameType(t, s) ||
2913 source.allowCovariantReturns() &&
2914 !t.isPrimitive() &&
2915 !s.isPrimitive() &&
2916 isAssignable(t, s, warner);
2917 }
2918 // </editor-fold>
2920 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
2921 /**
2922 * Return the class that boxes the given primitive.
2923 */
2924 public ClassSymbol boxedClass(Type t) {
2925 return reader.enterClass(syms.boxedName[t.tag]);
2926 }
2928 /**
2929 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
2930 */
2931 public Type boxedTypeOrType(Type t) {
2932 return t.isPrimitive() ?
2933 boxedClass(t).type :
2934 t;
2935 }
2937 /**
2938 * Return the primitive type corresponding to a boxed type.
2939 */
2940 public Type unboxedType(Type t) {
2941 if (allowBoxing) {
2942 for (int i=0; i<syms.boxedName.length; i++) {
2943 Name box = syms.boxedName[i];
2944 if (box != null &&
2945 asSuper(t, reader.enterClass(box)) != null)
2946 return syms.typeOfTag[i];
2947 }
2948 }
2949 return Type.noType;
2950 }
2951 // </editor-fold>
2953 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
2954 /*
2955 * JLS 3rd Ed. 5.1.10 Capture Conversion:
2956 *
2957 * Let G name a generic type declaration with n formal type
2958 * parameters A1 ... An with corresponding bounds U1 ... Un. There
2959 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
2960 * where, for 1 <= i <= n:
2961 *
2962 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
2963 * Si is a fresh type variable whose upper bound is
2964 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
2965 * type.
2966 *
2967 * + If Ti is a wildcard type argument of the form ? extends Bi,
2968 * then Si is a fresh type variable whose upper bound is
2969 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
2970 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
2971 * a compile-time error if for any two classes (not interfaces)
2972 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
2973 *
2974 * + If Ti is a wildcard type argument of the form ? super Bi,
2975 * then Si is a fresh type variable whose upper bound is
2976 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
2977 *
2978 * + Otherwise, Si = Ti.
2979 *
2980 * Capture conversion on any type other than a parameterized type
2981 * (4.5) acts as an identity conversion (5.1.1). Capture
2982 * conversions never require a special action at run time and
2983 * therefore never throw an exception at run time.
2984 *
2985 * Capture conversion is not applied recursively.
2986 */
2987 /**
2988 * Capture conversion as specified by JLS 3rd Ed.
2989 */
2991 public List<Type> capture(List<Type> ts) {
2992 List<Type> buf = List.nil();
2993 for (Type t : ts) {
2994 buf = buf.prepend(capture(t));
2995 }
2996 return buf.reverse();
2997 }
2998 public Type capture(Type t) {
2999 if (t.tag != CLASS)
3000 return t;
3001 if (t.getEnclosingType() != Type.noType) {
3002 Type capturedEncl = capture(t.getEnclosingType());
3003 if (capturedEncl != t.getEnclosingType()) {
3004 Type type1 = memberType(capturedEncl, t.tsym);
3005 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3006 }
3007 }
3008 ClassType cls = (ClassType)t;
3009 if (cls.isRaw() || !cls.isParameterized())
3010 return cls;
3012 ClassType G = (ClassType)cls.asElement().asType();
3013 List<Type> A = G.getTypeArguments();
3014 List<Type> T = cls.getTypeArguments();
3015 List<Type> S = freshTypeVariables(T);
3017 List<Type> currentA = A;
3018 List<Type> currentT = T;
3019 List<Type> currentS = S;
3020 boolean captured = false;
3021 while (!currentA.isEmpty() &&
3022 !currentT.isEmpty() &&
3023 !currentS.isEmpty()) {
3024 if (currentS.head != currentT.head) {
3025 captured = true;
3026 WildcardType Ti = (WildcardType)currentT.head;
3027 Type Ui = currentA.head.getUpperBound();
3028 CapturedType Si = (CapturedType)currentS.head;
3029 if (Ui == null)
3030 Ui = syms.objectType;
3031 switch (Ti.kind) {
3032 case UNBOUND:
3033 Si.bound = subst(Ui, A, S);
3034 Si.lower = syms.botType;
3035 break;
3036 case EXTENDS:
3037 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3038 Si.lower = syms.botType;
3039 break;
3040 case SUPER:
3041 Si.bound = subst(Ui, A, S);
3042 Si.lower = Ti.getSuperBound();
3043 break;
3044 }
3045 if (Si.bound == Si.lower)
3046 currentS.head = Si.bound;
3047 }
3048 currentA = currentA.tail;
3049 currentT = currentT.tail;
3050 currentS = currentS.tail;
3051 }
3052 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3053 return erasure(t); // some "rare" type involved
3055 if (captured)
3056 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3057 else
3058 return t;
3059 }
3060 // where
3061 public List<Type> freshTypeVariables(List<Type> types) {
3062 ListBuffer<Type> result = lb();
3063 for (Type t : types) {
3064 if (t.tag == WILDCARD) {
3065 Type bound = ((WildcardType)t).getExtendsBound();
3066 if (bound == null)
3067 bound = syms.objectType;
3068 result.append(new CapturedType(capturedName,
3069 syms.noSymbol,
3070 bound,
3071 syms.botType,
3072 (WildcardType)t));
3073 } else {
3074 result.append(t);
3075 }
3076 }
3077 return result.toList();
3078 }
3079 // </editor-fold>
3081 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3082 private List<Type> upperBounds(List<Type> ss) {
3083 if (ss.isEmpty()) return ss;
3084 Type head = upperBound(ss.head);
3085 List<Type> tail = upperBounds(ss.tail);
3086 if (head != ss.head || tail != ss.tail)
3087 return tail.prepend(head);
3088 else
3089 return ss;
3090 }
3092 private boolean sideCast(Type from, Type to, Warner warn) {
3093 // We are casting from type $from$ to type $to$, which are
3094 // non-final unrelated types. This method
3095 // tries to reject a cast by transferring type parameters
3096 // from $to$ to $from$ by common superinterfaces.
3097 boolean reverse = false;
3098 Type target = to;
3099 if ((to.tsym.flags() & INTERFACE) == 0) {
3100 assert (from.tsym.flags() & INTERFACE) != 0;
3101 reverse = true;
3102 to = from;
3103 from = target;
3104 }
3105 List<Type> commonSupers = superClosure(to, erasure(from));
3106 boolean giveWarning = commonSupers.isEmpty();
3107 // The arguments to the supers could be unified here to
3108 // get a more accurate analysis
3109 while (commonSupers.nonEmpty()) {
3110 Type t1 = asSuper(from, commonSupers.head.tsym);
3111 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3112 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3113 return false;
3114 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3115 commonSupers = commonSupers.tail;
3116 }
3117 if (giveWarning && !isReifiable(reverse ? from : to))
3118 warn.warnUnchecked();
3119 if (!source.allowCovariantReturns())
3120 // reject if there is a common method signature with
3121 // incompatible return types.
3122 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3123 return true;
3124 }
3126 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3127 // We are casting from type $from$ to type $to$, which are
3128 // unrelated types one of which is final and the other of
3129 // which is an interface. This method
3130 // tries to reject a cast by transferring type parameters
3131 // from the final class to the interface.
3132 boolean reverse = false;
3133 Type target = to;
3134 if ((to.tsym.flags() & INTERFACE) == 0) {
3135 assert (from.tsym.flags() & INTERFACE) != 0;
3136 reverse = true;
3137 to = from;
3138 from = target;
3139 }
3140 assert (from.tsym.flags() & FINAL) != 0;
3141 Type t1 = asSuper(from, to.tsym);
3142 if (t1 == null) return false;
3143 Type t2 = to;
3144 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3145 return false;
3146 if (!source.allowCovariantReturns())
3147 // reject if there is a common method signature with
3148 // incompatible return types.
3149 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3150 if (!isReifiable(target) &&
3151 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3152 warn.warnUnchecked();
3153 return true;
3154 }
3156 private boolean giveWarning(Type from, Type to) {
3157 Type subFrom = asSub(from, to.tsym);
3158 return to.isParameterized() &&
3159 (!(isUnbounded(to) ||
3160 isSubtype(from, to) ||
3161 ((subFrom != null) && containsType(to.allparams(), subFrom.allparams()))));
3162 }
3164 private List<Type> superClosure(Type t, Type s) {
3165 List<Type> cl = List.nil();
3166 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3167 if (isSubtype(s, erasure(l.head))) {
3168 cl = insert(cl, l.head);
3169 } else {
3170 cl = union(cl, superClosure(l.head, s));
3171 }
3172 }
3173 return cl;
3174 }
3176 private boolean containsTypeEquivalent(Type t, Type s) {
3177 return
3178 isSameType(t, s) || // shortcut
3179 containsType(t, s) && containsType(s, t);
3180 }
3182 // <editor-fold defaultstate="collapsed" desc="adapt">
3183 /**
3184 * Adapt a type by computing a substitution which maps a source
3185 * type to a target type.
3186 *
3187 * @param source the source type
3188 * @param target the target type
3189 * @param from the type variables of the computed substitution
3190 * @param to the types of the computed substitution.
3191 */
3192 public void adapt(Type source,
3193 Type target,
3194 ListBuffer<Type> from,
3195 ListBuffer<Type> to) throws AdaptFailure {
3196 new Adapter(from, to).adapt(source, target);
3197 }
3199 class Adapter extends SimpleVisitor<Void, Type> {
3201 ListBuffer<Type> from;
3202 ListBuffer<Type> to;
3203 Map<Symbol,Type> mapping;
3205 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3206 this.from = from;
3207 this.to = to;
3208 mapping = new HashMap<Symbol,Type>();
3209 }
3211 public void adapt(Type source, Type target) throws AdaptFailure {
3212 visit(source, target);
3213 List<Type> fromList = from.toList();
3214 List<Type> toList = to.toList();
3215 while (!fromList.isEmpty()) {
3216 Type val = mapping.get(fromList.head.tsym);
3217 if (toList.head != val)
3218 toList.head = val;
3219 fromList = fromList.tail;
3220 toList = toList.tail;
3221 }
3222 }
3224 @Override
3225 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3226 if (target.tag == CLASS)
3227 adaptRecursive(source.allparams(), target.allparams());
3228 return null;
3229 }
3231 @Override
3232 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3233 if (target.tag == ARRAY)
3234 adaptRecursive(elemtype(source), elemtype(target));
3235 return null;
3236 }
3238 @Override
3239 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3240 if (source.isExtendsBound())
3241 adaptRecursive(upperBound(source), upperBound(target));
3242 else if (source.isSuperBound())
3243 adaptRecursive(lowerBound(source), lowerBound(target));
3244 return null;
3245 }
3247 @Override
3248 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3249 // Check to see if there is
3250 // already a mapping for $source$, in which case
3251 // the old mapping will be merged with the new
3252 Type val = mapping.get(source.tsym);
3253 if (val != null) {
3254 if (val.isSuperBound() && target.isSuperBound()) {
3255 val = isSubtype(lowerBound(val), lowerBound(target))
3256 ? target : val;
3257 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3258 val = isSubtype(upperBound(val), upperBound(target))
3259 ? val : target;
3260 } else if (!isSameType(val, target)) {
3261 throw new AdaptFailure();
3262 }
3263 } else {
3264 val = target;
3265 from.append(source);
3266 to.append(target);
3267 }
3268 mapping.put(source.tsym, val);
3269 return null;
3270 }
3272 @Override
3273 public Void visitType(Type source, Type target) {
3274 return null;
3275 }
3277 private Set<TypePair> cache = new HashSet<TypePair>();
3279 private void adaptRecursive(Type source, Type target) {
3280 TypePair pair = new TypePair(source, target);
3281 if (cache.add(pair)) {
3282 try {
3283 visit(source, target);
3284 } finally {
3285 cache.remove(pair);
3286 }
3287 }
3288 }
3290 private void adaptRecursive(List<Type> source, List<Type> target) {
3291 if (source.length() == target.length()) {
3292 while (source.nonEmpty()) {
3293 adaptRecursive(source.head, target.head);
3294 source = source.tail;
3295 target = target.tail;
3296 }
3297 }
3298 }
3299 }
3301 public static class AdaptFailure extends RuntimeException {
3302 static final long serialVersionUID = -7490231548272701566L;
3303 }
3305 private void adaptSelf(Type t,
3306 ListBuffer<Type> from,
3307 ListBuffer<Type> to) {
3308 try {
3309 //if (t.tsym.type != t)
3310 adapt(t.tsym.type, t, from, to);
3311 } catch (AdaptFailure ex) {
3312 // Adapt should never fail calculating a mapping from
3313 // t.tsym.type to t as there can be no merge problem.
3314 throw new AssertionError(ex);
3315 }
3316 }
3317 // </editor-fold>
3319 /**
3320 * Rewrite all type variables (universal quantifiers) in the given
3321 * type to wildcards (existential quantifiers). This is used to
3322 * determine if a cast is allowed. For example, if high is true
3323 * and {@code T <: Number}, then {@code List<T>} is rewritten to
3324 * {@code List<? extends Number>}. Since {@code List<Integer> <:
3325 * List<? extends Number>} a {@code List<T>} can be cast to {@code
3326 * List<Integer>} with a warning.
3327 * @param t a type
3328 * @param high if true return an upper bound; otherwise a lower
3329 * bound
3330 * @param rewriteTypeVars only rewrite captured wildcards if false;
3331 * otherwise rewrite all type variables
3332 * @return the type rewritten with wildcards (existential
3333 * quantifiers) only
3334 */
3335 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
3336 return new Rewriter(high, rewriteTypeVars).visit(t);
3337 }
3339 class Rewriter extends UnaryVisitor<Type> {
3341 boolean high;
3342 boolean rewriteTypeVars;
3344 Rewriter(boolean high, boolean rewriteTypeVars) {
3345 this.high = high;
3346 this.rewriteTypeVars = rewriteTypeVars;
3347 }
3349 @Override
3350 public Type visitClassType(ClassType t, Void s) {
3351 ListBuffer<Type> rewritten = new ListBuffer<Type>();
3352 boolean changed = false;
3353 for (Type arg : t.allparams()) {
3354 Type bound = visit(arg);
3355 if (arg != bound) {
3356 changed = true;
3357 }
3358 rewritten.append(bound);
3359 }
3360 if (changed)
3361 return subst(t.tsym.type,
3362 t.tsym.type.allparams(),
3363 rewritten.toList());
3364 else
3365 return t;
3366 }
3368 public Type visitType(Type t, Void s) {
3369 return high ? upperBound(t) : lowerBound(t);
3370 }
3372 @Override
3373 public Type visitCapturedType(CapturedType t, Void s) {
3374 Type bound = visitWildcardType(t.wildcard, null);
3375 return (bound.contains(t)) ?
3376 erasure(bound) :
3377 bound;
3378 }
3380 @Override
3381 public Type visitTypeVar(TypeVar t, Void s) {
3382 if (rewriteTypeVars) {
3383 Type bound = high ?
3384 (t.bound.contains(t) ?
3385 erasure(t.bound) :
3386 visit(t.bound)) :
3387 syms.botType;
3388 return rewriteAsWildcardType(bound, t);
3389 }
3390 else
3391 return t;
3392 }
3394 @Override
3395 public Type visitWildcardType(WildcardType t, Void s) {
3396 Type bound = high ? t.getExtendsBound() :
3397 t.getSuperBound();
3398 if (bound == null)
3399 bound = high ? syms.objectType : syms.botType;
3400 return rewriteAsWildcardType(visit(bound), t.bound);
3401 }
3403 private Type rewriteAsWildcardType(Type bound, TypeVar formal) {
3404 return high ?
3405 makeExtendsWildcard(B(bound), formal) :
3406 makeSuperWildcard(B(bound), formal);
3407 }
3409 Type B(Type t) {
3410 while (t.tag == WILDCARD) {
3411 WildcardType w = (WildcardType)t;
3412 t = high ?
3413 w.getExtendsBound() :
3414 w.getSuperBound();
3415 if (t == null) {
3416 t = high ? syms.objectType : syms.botType;
3417 }
3418 }
3419 return t;
3420 }
3421 }
3424 /**
3425 * Create a wildcard with the given upper (extends) bound; create
3426 * an unbounded wildcard if bound is Object.
3427 *
3428 * @param bound the upper bound
3429 * @param formal the formal type parameter that will be
3430 * substituted by the wildcard
3431 */
3432 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
3433 if (bound == syms.objectType) {
3434 return new WildcardType(syms.objectType,
3435 BoundKind.UNBOUND,
3436 syms.boundClass,
3437 formal);
3438 } else {
3439 return new WildcardType(bound,
3440 BoundKind.EXTENDS,
3441 syms.boundClass,
3442 formal);
3443 }
3444 }
3446 /**
3447 * Create a wildcard with the given lower (super) bound; create an
3448 * unbounded wildcard if bound is bottom (type of {@code null}).
3449 *
3450 * @param bound the lower bound
3451 * @param formal the formal type parameter that will be
3452 * substituted by the wildcard
3453 */
3454 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
3455 if (bound.tag == BOT) {
3456 return new WildcardType(syms.objectType,
3457 BoundKind.UNBOUND,
3458 syms.boundClass,
3459 formal);
3460 } else {
3461 return new WildcardType(bound,
3462 BoundKind.SUPER,
3463 syms.boundClass,
3464 formal);
3465 }
3466 }
3468 /**
3469 * A wrapper for a type that allows use in sets.
3470 */
3471 class SingletonType {
3472 final Type t;
3473 SingletonType(Type t) {
3474 this.t = t;
3475 }
3476 public int hashCode() {
3477 return Types.hashCode(t);
3478 }
3479 public boolean equals(Object obj) {
3480 return (obj instanceof SingletonType) &&
3481 isSameType(t, ((SingletonType)obj).t);
3482 }
3483 public String toString() {
3484 return t.toString();
3485 }
3486 }
3487 // </editor-fold>
3489 // <editor-fold defaultstate="collapsed" desc="Visitors">
3490 /**
3491 * A default visitor for types. All visitor methods except
3492 * visitType are implemented by delegating to visitType. Concrete
3493 * subclasses must provide an implementation of visitType and can
3494 * override other methods as needed.
3495 *
3496 * @param <R> the return type of the operation implemented by this
3497 * visitor; use Void if no return type is needed.
3498 * @param <S> the type of the second argument (the first being the
3499 * type itself) of the operation implemented by this visitor; use
3500 * Void if a second argument is not needed.
3501 */
3502 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
3503 final public R visit(Type t, S s) { return t.accept(this, s); }
3504 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
3505 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
3506 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
3507 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
3508 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
3509 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
3510 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
3511 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
3512 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
3513 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
3514 }
3516 /**
3517 * A default visitor for symbols. All visitor methods except
3518 * visitSymbol are implemented by delegating to visitSymbol. Concrete
3519 * subclasses must provide an implementation of visitSymbol and can
3520 * override other methods as needed.
3521 *
3522 * @param <R> the return type of the operation implemented by this
3523 * visitor; use Void if no return type is needed.
3524 * @param <S> the type of the second argument (the first being the
3525 * symbol itself) of the operation implemented by this visitor; use
3526 * Void if a second argument is not needed.
3527 */
3528 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
3529 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
3530 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
3531 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
3532 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
3533 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
3534 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
3535 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
3536 }
3538 /**
3539 * A <em>simple</em> visitor for types. This visitor is simple as
3540 * captured wildcards, for-all types (generic methods), and
3541 * undetermined type variables (part of inference) are hidden.
3542 * Captured wildcards are hidden by treating them as type
3543 * variables and the rest are hidden by visiting their qtypes.
3544 *
3545 * @param <R> the return type of the operation implemented by this
3546 * visitor; use Void if no return type is needed.
3547 * @param <S> the type of the second argument (the first being the
3548 * type itself) of the operation implemented by this visitor; use
3549 * Void if a second argument is not needed.
3550 */
3551 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
3552 @Override
3553 public R visitCapturedType(CapturedType t, S s) {
3554 return visitTypeVar(t, s);
3555 }
3556 @Override
3557 public R visitForAll(ForAll t, S s) {
3558 return visit(t.qtype, s);
3559 }
3560 @Override
3561 public R visitUndetVar(UndetVar t, S s) {
3562 return visit(t.qtype, s);
3563 }
3564 }
3566 /**
3567 * A plain relation on types. That is a 2-ary function on the
3568 * form Type × Type → Boolean.
3569 * <!-- In plain text: Type x Type -> Boolean -->
3570 */
3571 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
3573 /**
3574 * A convenience visitor for implementing operations that only
3575 * require one argument (the type itself), that is, unary
3576 * operations.
3577 *
3578 * @param <R> the return type of the operation implemented by this
3579 * visitor; use Void if no return type is needed.
3580 */
3581 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
3582 final public R visit(Type t) { return t.accept(this, null); }
3583 }
3585 /**
3586 * A visitor for implementing a mapping from types to types. The
3587 * default behavior of this class is to implement the identity
3588 * mapping (mapping a type to itself). This can be overridden in
3589 * subclasses.
3590 *
3591 * @param <S> the type of the second argument (the first being the
3592 * type itself) of this mapping; use Void if a second argument is
3593 * not needed.
3594 */
3595 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
3596 final public Type visit(Type t) { return t.accept(this, null); }
3597 public Type visitType(Type t, S s) { return t; }
3598 }
3599 // </editor-fold>
3602 // <editor-fold defaultstate="collapsed" desc="Annotation support">
3604 public RetentionPolicy getRetention(Attribute.Compound a) {
3605 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
3606 Attribute.Compound c = a.type.tsym.attribute(syms.retentionType.tsym);
3607 if (c != null) {
3608 Attribute value = c.member(names.value);
3609 if (value != null && value instanceof Attribute.Enum) {
3610 Name levelName = ((Attribute.Enum)value).value.name;
3611 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
3612 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
3613 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
3614 else ;// /* fail soft */ throw new AssertionError(levelName);
3615 }
3616 }
3617 return vis;
3618 }
3619 // </editor-fold>
3620 }
