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src/share/classes/com/sun/tools/javac/code/Types.java@f2fdd52e4e87
src/share/classes/com/sun/tools/javac/code/Types.java
Thu, 10 Jun 2010 16:08:01 -0700
- author
- jjg
- date
- Thu, 10 Jun 2010 16:08:01 -0700
- changeset 581
- f2fdd52e4e87
- parent 567
- 593a59e40bdb
- child 637
- c655e0280bdc
- permissions
- -rw-r--r--
6944312: Potential rebranding issues in openjdk/langtools repository sources
Reviewed-by: darcy
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.comp.Check;
37 import static com.sun.tools.javac.code.Type.*;
38 import static com.sun.tools.javac.code.TypeTags.*;
39 import static com.sun.tools.javac.code.Symbol.*;
40 import static com.sun.tools.javac.code.Flags.*;
41 import static com.sun.tools.javac.code.BoundKind.*;
42 import static com.sun.tools.javac.util.ListBuffer.lb;
44 /**
45 * Utility class containing various operations on types.
46 *
47 * <p>Unless other names are more illustrative, the following naming
48 * conventions should be observed in this file:
49 *
50 * <dl>
51 * <dt>t</dt>
52 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
53 * <dt>s</dt>
54 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
55 * <dt>ts</dt>
56 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
57 * <dt>ss</dt>
58 * <dd>A second list of types should be named ss.</dd>
59 * </dl>
60 *
61 * <p><b>This is NOT part of any supported API.
62 * If you write code that depends on this, you do so at your own risk.
63 * This code and its internal interfaces are subject to change or
64 * deletion without notice.</b>
65 */
66 public class Types {
67 protected static final Context.Key<Types> typesKey =
68 new Context.Key<Types>();
70 final Symtab syms;
71 final JavacMessages messages;
72 final Names names;
73 final boolean allowBoxing;
74 final ClassReader reader;
75 final Source source;
76 final Check chk;
77 List<Warner> warnStack = List.nil();
78 final Name capturedName;
80 // <editor-fold defaultstate="collapsed" desc="Instantiating">
81 public static Types instance(Context context) {
82 Types instance = context.get(typesKey);
83 if (instance == null)
84 instance = new Types(context);
85 return instance;
86 }
88 protected Types(Context context) {
89 context.put(typesKey, this);
90 syms = Symtab.instance(context);
91 names = Names.instance(context);
92 allowBoxing = Source.instance(context).allowBoxing();
93 reader = ClassReader.instance(context);
94 source = Source.instance(context);
95 chk = Check.instance(context);
96 capturedName = names.fromString("<captured wildcard>");
97 messages = JavacMessages.instance(context);
98 }
99 // </editor-fold>
101 // <editor-fold defaultstate="collapsed" desc="upperBound">
102 /**
103 * The "rvalue conversion".<br>
104 * The upper bound of most types is the type
105 * itself. Wildcards, on the other hand have upper
106 * and lower bounds.
107 * @param t a type
108 * @return the upper bound of the given type
109 */
110 public Type upperBound(Type t) {
111 return upperBound.visit(t);
112 }
113 // where
114 private final MapVisitor<Void> upperBound = new MapVisitor<Void>() {
116 @Override
117 public Type visitWildcardType(WildcardType t, Void ignored) {
118 if (t.isSuperBound())
119 return t.bound == null ? syms.objectType : t.bound.bound;
120 else
121 return visit(t.type);
122 }
124 @Override
125 public Type visitCapturedType(CapturedType t, Void ignored) {
126 return visit(t.bound);
127 }
128 };
129 // </editor-fold>
131 // <editor-fold defaultstate="collapsed" desc="lowerBound">
132 /**
133 * The "lvalue conversion".<br>
134 * The lower bound of most types is the type
135 * itself. Wildcards, on the other hand have upper
136 * and lower bounds.
137 * @param t a type
138 * @return the lower bound of the given type
139 */
140 public Type lowerBound(Type t) {
141 return lowerBound.visit(t);
142 }
143 // where
144 private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() {
146 @Override
147 public Type visitWildcardType(WildcardType t, Void ignored) {
148 return t.isExtendsBound() ? syms.botType : visit(t.type);
149 }
151 @Override
152 public Type visitCapturedType(CapturedType t, Void ignored) {
153 return visit(t.getLowerBound());
154 }
155 };
156 // </editor-fold>
158 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
159 /**
160 * Checks that all the arguments to a class are unbounded
161 * wildcards or something else that doesn't make any restrictions
162 * on the arguments. If a class isUnbounded, a raw super- or
163 * subclass can be cast to it without a warning.
164 * @param t a type
165 * @return true iff the given type is unbounded or raw
166 */
167 public boolean isUnbounded(Type t) {
168 return isUnbounded.visit(t);
169 }
170 // where
171 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
173 public Boolean visitType(Type t, Void ignored) {
174 return true;
175 }
177 @Override
178 public Boolean visitClassType(ClassType t, Void ignored) {
179 List<Type> parms = t.tsym.type.allparams();
180 List<Type> args = t.allparams();
181 while (parms.nonEmpty()) {
182 WildcardType unb = new WildcardType(syms.objectType,
183 BoundKind.UNBOUND,
184 syms.boundClass,
185 (TypeVar)parms.head);
186 if (!containsType(args.head, unb))
187 return false;
188 parms = parms.tail;
189 args = args.tail;
190 }
191 return true;
192 }
193 };
194 // </editor-fold>
196 // <editor-fold defaultstate="collapsed" desc="asSub">
197 /**
198 * Return the least specific subtype of t that starts with symbol
199 * sym. If none exists, return null. The least specific subtype
200 * is determined as follows:
201 *
202 * <p>If there is exactly one parameterized instance of sym that is a
203 * subtype of t, that parameterized instance is returned.<br>
204 * Otherwise, if the plain type or raw type `sym' is a subtype of
205 * type t, the type `sym' itself is returned. Otherwise, null is
206 * returned.
207 */
208 public Type asSub(Type t, Symbol sym) {
209 return asSub.visit(t, sym);
210 }
211 // where
212 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
214 public Type visitType(Type t, Symbol sym) {
215 return null;
216 }
218 @Override
219 public Type visitClassType(ClassType t, Symbol sym) {
220 if (t.tsym == sym)
221 return t;
222 Type base = asSuper(sym.type, t.tsym);
223 if (base == null)
224 return null;
225 ListBuffer<Type> from = new ListBuffer<Type>();
226 ListBuffer<Type> to = new ListBuffer<Type>();
227 try {
228 adapt(base, t, from, to);
229 } catch (AdaptFailure ex) {
230 return null;
231 }
232 Type res = subst(sym.type, from.toList(), to.toList());
233 if (!isSubtype(res, t))
234 return null;
235 ListBuffer<Type> openVars = new ListBuffer<Type>();
236 for (List<Type> l = sym.type.allparams();
237 l.nonEmpty(); l = l.tail)
238 if (res.contains(l.head) && !t.contains(l.head))
239 openVars.append(l.head);
240 if (openVars.nonEmpty()) {
241 if (t.isRaw()) {
242 // The subtype of a raw type is raw
243 res = erasure(res);
244 } else {
245 // Unbound type arguments default to ?
246 List<Type> opens = openVars.toList();
247 ListBuffer<Type> qs = new ListBuffer<Type>();
248 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
249 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head));
250 }
251 res = subst(res, opens, qs.toList());
252 }
253 }
254 return res;
255 }
257 @Override
258 public Type visitErrorType(ErrorType t, Symbol sym) {
259 return t;
260 }
261 };
262 // </editor-fold>
264 // <editor-fold defaultstate="collapsed" desc="isConvertible">
265 /**
266 * Is t a subtype of or convertiable via boxing/unboxing
267 * convertions to s?
268 */
269 public boolean isConvertible(Type t, Type s, Warner warn) {
270 boolean tPrimitive = t.isPrimitive();
271 boolean sPrimitive = s.isPrimitive();
272 if (tPrimitive == sPrimitive)
273 return isSubtypeUnchecked(t, s, warn);
274 if (!allowBoxing) return false;
275 return tPrimitive
276 ? isSubtype(boxedClass(t).type, s)
277 : isSubtype(unboxedType(t), s);
278 }
280 /**
281 * Is t a subtype of or convertiable via boxing/unboxing
282 * convertions to s?
283 */
284 public boolean isConvertible(Type t, Type s) {
285 return isConvertible(t, s, Warner.noWarnings);
286 }
287 // </editor-fold>
289 // <editor-fold defaultstate="collapsed" desc="isSubtype">
290 /**
291 * Is t an unchecked subtype of s?
292 */
293 public boolean isSubtypeUnchecked(Type t, Type s) {
294 return isSubtypeUnchecked(t, s, Warner.noWarnings);
295 }
296 /**
297 * Is t an unchecked subtype of s?
298 */
299 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
300 if (t.tag == ARRAY && s.tag == ARRAY) {
301 return (((ArrayType)t).elemtype.tag <= lastBaseTag)
302 ? isSameType(elemtype(t), elemtype(s))
303 : isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
304 } else if (isSubtype(t, s)) {
305 return true;
306 }
307 else if (t.tag == TYPEVAR) {
308 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
309 }
310 else if (s.tag == UNDETVAR) {
311 UndetVar uv = (UndetVar)s;
312 if (uv.inst != null)
313 return isSubtypeUnchecked(t, uv.inst, warn);
314 }
315 else if (!s.isRaw()) {
316 Type t2 = asSuper(t, s.tsym);
317 if (t2 != null && t2.isRaw()) {
318 if (isReifiable(s))
319 warn.silentUnchecked();
320 else
321 warn.warnUnchecked();
322 return true;
323 }
324 }
325 return false;
326 }
328 /**
329 * Is t a subtype of s?<br>
330 * (not defined for Method and ForAll types)
331 */
332 final public boolean isSubtype(Type t, Type s) {
333 return isSubtype(t, s, true);
334 }
335 final public boolean isSubtypeNoCapture(Type t, Type s) {
336 return isSubtype(t, s, false);
337 }
338 public boolean isSubtype(Type t, Type s, boolean capture) {
339 if (t == s)
340 return true;
342 if (s.tag >= firstPartialTag)
343 return isSuperType(s, t);
345 if (s.isCompound()) {
346 for (Type s2 : interfaces(s).prepend(supertype(s))) {
347 if (!isSubtype(t, s2, capture))
348 return false;
349 }
350 return true;
351 }
353 Type lower = lowerBound(s);
354 if (s != lower)
355 return isSubtype(capture ? capture(t) : t, lower, false);
357 return isSubtype.visit(capture ? capture(t) : t, s);
358 }
359 // where
360 private TypeRelation isSubtype = new TypeRelation()
361 {
362 public Boolean visitType(Type t, Type s) {
363 switch (t.tag) {
364 case BYTE: case CHAR:
365 return (t.tag == s.tag ||
366 t.tag + 2 <= s.tag && s.tag <= DOUBLE);
367 case SHORT: case INT: case LONG: case FLOAT: case DOUBLE:
368 return t.tag <= s.tag && s.tag <= DOUBLE;
369 case BOOLEAN: case VOID:
370 return t.tag == s.tag;
371 case TYPEVAR:
372 return isSubtypeNoCapture(t.getUpperBound(), s);
373 case BOT:
374 return
375 s.tag == BOT || s.tag == CLASS ||
376 s.tag == ARRAY || s.tag == TYPEVAR;
377 case NONE:
378 return false;
379 default:
380 throw new AssertionError("isSubtype " + t.tag);
381 }
382 }
384 private Set<TypePair> cache = new HashSet<TypePair>();
386 private boolean containsTypeRecursive(Type t, Type s) {
387 TypePair pair = new TypePair(t, s);
388 if (cache.add(pair)) {
389 try {
390 return containsType(t.getTypeArguments(),
391 s.getTypeArguments());
392 } finally {
393 cache.remove(pair);
394 }
395 } else {
396 return containsType(t.getTypeArguments(),
397 rewriteSupers(s).getTypeArguments());
398 }
399 }
401 private Type rewriteSupers(Type t) {
402 if (!t.isParameterized())
403 return t;
404 ListBuffer<Type> from = lb();
405 ListBuffer<Type> to = lb();
406 adaptSelf(t, from, to);
407 if (from.isEmpty())
408 return t;
409 ListBuffer<Type> rewrite = lb();
410 boolean changed = false;
411 for (Type orig : to.toList()) {
412 Type s = rewriteSupers(orig);
413 if (s.isSuperBound() && !s.isExtendsBound()) {
414 s = new WildcardType(syms.objectType,
415 BoundKind.UNBOUND,
416 syms.boundClass);
417 changed = true;
418 } else if (s != orig) {
419 s = new WildcardType(upperBound(s),
420 BoundKind.EXTENDS,
421 syms.boundClass);
422 changed = true;
423 }
424 rewrite.append(s);
425 }
426 if (changed)
427 return subst(t.tsym.type, from.toList(), rewrite.toList());
428 else
429 return t;
430 }
432 @Override
433 public Boolean visitClassType(ClassType t, Type s) {
434 Type sup = asSuper(t, s.tsym);
435 return sup != null
436 && sup.tsym == s.tsym
437 // You're not allowed to write
438 // Vector<Object> vec = new Vector<String>();
439 // But with wildcards you can write
440 // Vector<? extends Object> vec = new Vector<String>();
441 // which means that subtype checking must be done
442 // here instead of same-type checking (via containsType).
443 && (!s.isParameterized() || containsTypeRecursive(s, sup))
444 && isSubtypeNoCapture(sup.getEnclosingType(),
445 s.getEnclosingType());
446 }
448 @Override
449 public Boolean visitArrayType(ArrayType t, Type s) {
450 if (s.tag == ARRAY) {
451 if (t.elemtype.tag <= lastBaseTag)
452 return isSameType(t.elemtype, elemtype(s));
453 else
454 return isSubtypeNoCapture(t.elemtype, elemtype(s));
455 }
457 if (s.tag == CLASS) {
458 Name sname = s.tsym.getQualifiedName();
459 return sname == names.java_lang_Object
460 || sname == names.java_lang_Cloneable
461 || sname == names.java_io_Serializable;
462 }
464 return false;
465 }
467 @Override
468 public Boolean visitUndetVar(UndetVar t, Type s) {
469 //todo: test against origin needed? or replace with substitution?
470 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
471 return true;
473 if (t.inst != null)
474 return isSubtypeNoCapture(t.inst, s); // TODO: ", warn"?
476 t.hibounds = t.hibounds.prepend(s);
477 return true;
478 }
480 @Override
481 public Boolean visitErrorType(ErrorType t, Type s) {
482 return true;
483 }
484 };
486 /**
487 * Is t a subtype of every type in given list `ts'?<br>
488 * (not defined for Method and ForAll types)<br>
489 * Allows unchecked conversions.
490 */
491 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
492 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
493 if (!isSubtypeUnchecked(t, l.head, warn))
494 return false;
495 return true;
496 }
498 /**
499 * Are corresponding elements of ts subtypes of ss? If lists are
500 * of different length, return false.
501 */
502 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
503 while (ts.tail != null && ss.tail != null
504 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
505 isSubtype(ts.head, ss.head)) {
506 ts = ts.tail;
507 ss = ss.tail;
508 }
509 return ts.tail == null && ss.tail == null;
510 /*inlined: ts.isEmpty() && ss.isEmpty();*/
511 }
513 /**
514 * Are corresponding elements of ts subtypes of ss, allowing
515 * unchecked conversions? If lists are of different length,
516 * return false.
517 **/
518 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
519 while (ts.tail != null && ss.tail != null
520 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
521 isSubtypeUnchecked(ts.head, ss.head, warn)) {
522 ts = ts.tail;
523 ss = ss.tail;
524 }
525 return ts.tail == null && ss.tail == null;
526 /*inlined: ts.isEmpty() && ss.isEmpty();*/
527 }
528 // </editor-fold>
530 // <editor-fold defaultstate="collapsed" desc="isSuperType">
531 /**
532 * Is t a supertype of s?
533 */
534 public boolean isSuperType(Type t, Type s) {
535 switch (t.tag) {
536 case ERROR:
537 return true;
538 case UNDETVAR: {
539 UndetVar undet = (UndetVar)t;
540 if (t == s ||
541 undet.qtype == s ||
542 s.tag == ERROR ||
543 s.tag == BOT) return true;
544 if (undet.inst != null)
545 return isSubtype(s, undet.inst);
546 undet.lobounds = undet.lobounds.prepend(s);
547 return true;
548 }
549 default:
550 return isSubtype(s, t);
551 }
552 }
553 // </editor-fold>
555 // <editor-fold defaultstate="collapsed" desc="isSameType">
556 /**
557 * Are corresponding elements of the lists the same type? If
558 * lists are of different length, return false.
559 */
560 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
561 while (ts.tail != null && ss.tail != null
562 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
563 isSameType(ts.head, ss.head)) {
564 ts = ts.tail;
565 ss = ss.tail;
566 }
567 return ts.tail == null && ss.tail == null;
568 /*inlined: ts.isEmpty() && ss.isEmpty();*/
569 }
571 /**
572 * Is t the same type as s?
573 */
574 public boolean isSameType(Type t, Type s) {
575 return isSameType.visit(t, s);
576 }
577 // where
578 private TypeRelation isSameType = new TypeRelation() {
580 public Boolean visitType(Type t, Type s) {
581 if (t == s)
582 return true;
584 if (s.tag >= firstPartialTag)
585 return visit(s, t);
587 switch (t.tag) {
588 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
589 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
590 return t.tag == s.tag;
591 case TYPEVAR: {
592 if (s.tag == TYPEVAR) {
593 //type-substitution does not preserve type-var types
594 //check that type var symbols and bounds are indeed the same
595 return t.tsym == s.tsym &&
596 visit(t.getUpperBound(), s.getUpperBound());
597 }
598 else {
599 //special case for s == ? super X, where upper(s) = u
600 //check that u == t, where u has been set by Type.withTypeVar
601 return s.isSuperBound() &&
602 !s.isExtendsBound() &&
603 visit(t, upperBound(s));
604 }
605 }
606 default:
607 throw new AssertionError("isSameType " + t.tag);
608 }
609 }
611 @Override
612 public Boolean visitWildcardType(WildcardType t, Type s) {
613 if (s.tag >= firstPartialTag)
614 return visit(s, t);
615 else
616 return false;
617 }
619 @Override
620 public Boolean visitClassType(ClassType t, Type s) {
621 if (t == s)
622 return true;
624 if (s.tag >= firstPartialTag)
625 return visit(s, t);
627 if (s.isSuperBound() && !s.isExtendsBound())
628 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
630 if (t.isCompound() && s.isCompound()) {
631 if (!visit(supertype(t), supertype(s)))
632 return false;
634 HashSet<SingletonType> set = new HashSet<SingletonType>();
635 for (Type x : interfaces(t))
636 set.add(new SingletonType(x));
637 for (Type x : interfaces(s)) {
638 if (!set.remove(new SingletonType(x)))
639 return false;
640 }
641 return (set.size() == 0);
642 }
643 return t.tsym == s.tsym
644 && visit(t.getEnclosingType(), s.getEnclosingType())
645 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
646 }
648 @Override
649 public Boolean visitArrayType(ArrayType t, Type s) {
650 if (t == s)
651 return true;
653 if (s.tag >= firstPartialTag)
654 return visit(s, t);
656 return s.tag == ARRAY
657 && containsTypeEquivalent(t.elemtype, elemtype(s));
658 }
660 @Override
661 public Boolean visitMethodType(MethodType t, Type s) {
662 // isSameType for methods does not take thrown
663 // exceptions into account!
664 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
665 }
667 @Override
668 public Boolean visitPackageType(PackageType t, Type s) {
669 return t == s;
670 }
672 @Override
673 public Boolean visitForAll(ForAll t, Type s) {
674 if (s.tag != FORALL)
675 return false;
677 ForAll forAll = (ForAll)s;
678 return hasSameBounds(t, forAll)
679 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
680 }
682 @Override
683 public Boolean visitUndetVar(UndetVar t, Type s) {
684 if (s.tag == WILDCARD)
685 // FIXME, this might be leftovers from before capture conversion
686 return false;
688 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
689 return true;
691 if (t.inst != null)
692 return visit(t.inst, s);
694 t.inst = fromUnknownFun.apply(s);
695 for (List<Type> l = t.lobounds; l.nonEmpty(); l = l.tail) {
696 if (!isSubtype(l.head, t.inst))
697 return false;
698 }
699 for (List<Type> l = t.hibounds; l.nonEmpty(); l = l.tail) {
700 if (!isSubtype(t.inst, l.head))
701 return false;
702 }
703 return true;
704 }
706 @Override
707 public Boolean visitErrorType(ErrorType t, Type s) {
708 return true;
709 }
710 };
711 // </editor-fold>
713 // <editor-fold defaultstate="collapsed" desc="fromUnknownFun">
714 /**
715 * A mapping that turns all unknown types in this type to fresh
716 * unknown variables.
717 */
718 public Mapping fromUnknownFun = new Mapping("fromUnknownFun") {
719 public Type apply(Type t) {
720 if (t.tag == UNKNOWN) return new UndetVar(t);
721 else return t.map(this);
722 }
723 };
724 // </editor-fold>
726 // <editor-fold defaultstate="collapsed" desc="Contains Type">
727 public boolean containedBy(Type t, Type s) {
728 switch (t.tag) {
729 case UNDETVAR:
730 if (s.tag == WILDCARD) {
731 UndetVar undetvar = (UndetVar)t;
732 WildcardType wt = (WildcardType)s;
733 switch(wt.kind) {
734 case UNBOUND: //similar to ? extends Object
735 case EXTENDS: {
736 Type bound = upperBound(s);
737 // We should check the new upper bound against any of the
738 // undetvar's lower bounds.
739 for (Type t2 : undetvar.lobounds) {
740 if (!isSubtype(t2, bound))
741 return false;
742 }
743 undetvar.hibounds = undetvar.hibounds.prepend(bound);
744 break;
745 }
746 case SUPER: {
747 Type bound = lowerBound(s);
748 // We should check the new lower bound against any of the
749 // undetvar's lower bounds.
750 for (Type t2 : undetvar.hibounds) {
751 if (!isSubtype(bound, t2))
752 return false;
753 }
754 undetvar.lobounds = undetvar.lobounds.prepend(bound);
755 break;
756 }
757 }
758 return true;
759 } else {
760 return isSameType(t, s);
761 }
762 case ERROR:
763 return true;
764 default:
765 return containsType(s, t);
766 }
767 }
769 boolean containsType(List<Type> ts, List<Type> ss) {
770 while (ts.nonEmpty() && ss.nonEmpty()
771 && containsType(ts.head, ss.head)) {
772 ts = ts.tail;
773 ss = ss.tail;
774 }
775 return ts.isEmpty() && ss.isEmpty();
776 }
778 /**
779 * Check if t contains s.
780 *
781 * <p>T contains S if:
782 *
783 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
784 *
785 * <p>This relation is only used by ClassType.isSubtype(), that
786 * is,
787 *
788 * <p>{@code C<S> <: C<T> if T contains S.}
789 *
790 * <p>Because of F-bounds, this relation can lead to infinite
791 * recursion. Thus we must somehow break that recursion. Notice
792 * that containsType() is only called from ClassType.isSubtype().
793 * Since the arguments have already been checked against their
794 * bounds, we know:
795 *
796 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
797 *
798 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
799 *
800 * @param t a type
801 * @param s a type
802 */
803 public boolean containsType(Type t, Type s) {
804 return containsType.visit(t, s);
805 }
806 // where
807 private TypeRelation containsType = new TypeRelation() {
809 private Type U(Type t) {
810 while (t.tag == WILDCARD) {
811 WildcardType w = (WildcardType)t;
812 if (w.isSuperBound())
813 return w.bound == null ? syms.objectType : w.bound.bound;
814 else
815 t = w.type;
816 }
817 return t;
818 }
820 private Type L(Type t) {
821 while (t.tag == WILDCARD) {
822 WildcardType w = (WildcardType)t;
823 if (w.isExtendsBound())
824 return syms.botType;
825 else
826 t = w.type;
827 }
828 return t;
829 }
831 public Boolean visitType(Type t, Type s) {
832 if (s.tag >= firstPartialTag)
833 return containedBy(s, t);
834 else
835 return isSameType(t, s);
836 }
838 void debugContainsType(WildcardType t, Type s) {
839 System.err.println();
840 System.err.format(" does %s contain %s?%n", t, s);
841 System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
842 upperBound(s), s, t, U(t),
843 t.isSuperBound()
844 || isSubtypeNoCapture(upperBound(s), U(t)));
845 System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
846 L(t), t, s, lowerBound(s),
847 t.isExtendsBound()
848 || isSubtypeNoCapture(L(t), lowerBound(s)));
849 System.err.println();
850 }
852 @Override
853 public Boolean visitWildcardType(WildcardType t, Type s) {
854 if (s.tag >= firstPartialTag)
855 return containedBy(s, t);
856 else {
857 // debugContainsType(t, s);
858 return isSameWildcard(t, s)
859 || isCaptureOf(s, t)
860 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
861 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
862 }
863 }
865 @Override
866 public Boolean visitUndetVar(UndetVar t, Type s) {
867 if (s.tag != WILDCARD)
868 return isSameType(t, s);
869 else
870 return false;
871 }
873 @Override
874 public Boolean visitErrorType(ErrorType t, Type s) {
875 return true;
876 }
877 };
879 public boolean isCaptureOf(Type s, WildcardType t) {
880 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
881 return false;
882 return isSameWildcard(t, ((CapturedType)s).wildcard);
883 }
885 public boolean isSameWildcard(WildcardType t, Type s) {
886 if (s.tag != WILDCARD)
887 return false;
888 WildcardType w = (WildcardType)s;
889 return w.kind == t.kind && w.type == t.type;
890 }
892 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
893 while (ts.nonEmpty() && ss.nonEmpty()
894 && containsTypeEquivalent(ts.head, ss.head)) {
895 ts = ts.tail;
896 ss = ss.tail;
897 }
898 return ts.isEmpty() && ss.isEmpty();
899 }
900 // </editor-fold>
902 // <editor-fold defaultstate="collapsed" desc="isCastable">
903 public boolean isCastable(Type t, Type s) {
904 return isCastable(t, s, Warner.noWarnings);
905 }
907 /**
908 * Is t is castable to s?<br>
909 * s is assumed to be an erased type.<br>
910 * (not defined for Method and ForAll types).
911 */
912 public boolean isCastable(Type t, Type s, Warner warn) {
913 if (t == s)
914 return true;
916 if (t.isPrimitive() != s.isPrimitive())
917 return allowBoxing && isConvertible(t, s, warn);
919 if (warn != warnStack.head) {
920 try {
921 warnStack = warnStack.prepend(warn);
922 return isCastable.visit(t,s);
923 } finally {
924 warnStack = warnStack.tail;
925 }
926 } else {
927 return isCastable.visit(t,s);
928 }
929 }
930 // where
931 private TypeRelation isCastable = new TypeRelation() {
933 public Boolean visitType(Type t, Type s) {
934 if (s.tag == ERROR)
935 return true;
937 switch (t.tag) {
938 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
939 case DOUBLE:
940 return s.tag <= DOUBLE;
941 case BOOLEAN:
942 return s.tag == BOOLEAN;
943 case VOID:
944 return false;
945 case BOT:
946 return isSubtype(t, s);
947 default:
948 throw new AssertionError();
949 }
950 }
952 @Override
953 public Boolean visitWildcardType(WildcardType t, Type s) {
954 return isCastable(upperBound(t), s, warnStack.head);
955 }
957 @Override
958 public Boolean visitClassType(ClassType t, Type s) {
959 if (s.tag == ERROR || s.tag == BOT)
960 return true;
962 if (s.tag == TYPEVAR) {
963 if (isCastable(s.getUpperBound(), t, Warner.noWarnings)) {
964 warnStack.head.warnUnchecked();
965 return true;
966 } else {
967 return false;
968 }
969 }
971 if (t.isCompound()) {
972 Warner oldWarner = warnStack.head;
973 warnStack.head = Warner.noWarnings;
974 if (!visit(supertype(t), s))
975 return false;
976 for (Type intf : interfaces(t)) {
977 if (!visit(intf, s))
978 return false;
979 }
980 if (warnStack.head.unchecked == true)
981 oldWarner.warnUnchecked();
982 return true;
983 }
985 if (s.isCompound()) {
986 // call recursively to reuse the above code
987 return visitClassType((ClassType)s, t);
988 }
990 if (s.tag == CLASS || s.tag == ARRAY) {
991 boolean upcast;
992 if ((upcast = isSubtype(erasure(t), erasure(s)))
993 || isSubtype(erasure(s), erasure(t))) {
994 if (!upcast && s.tag == ARRAY) {
995 if (!isReifiable(s))
996 warnStack.head.warnUnchecked();
997 return true;
998 } else if (s.isRaw()) {
999 return true;
1000 } else if (t.isRaw()) {
1001 if (!isUnbounded(s))
1002 warnStack.head.warnUnchecked();
1003 return true;
1004 }
1005 // Assume |a| <: |b|
1006 final Type a = upcast ? t : s;
1007 final Type b = upcast ? s : t;
1008 final boolean HIGH = true;
1009 final boolean LOW = false;
1010 final boolean DONT_REWRITE_TYPEVARS = false;
1011 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1012 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1013 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1014 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1015 Type lowSub = asSub(bLow, aLow.tsym);
1016 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1017 if (highSub == null) {
1018 final boolean REWRITE_TYPEVARS = true;
1019 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1020 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1021 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1022 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1023 lowSub = asSub(bLow, aLow.tsym);
1024 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1025 }
1026 if (highSub != null) {
1027 assert a.tsym == highSub.tsym && a.tsym == lowSub.tsym
1028 : a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym;
1029 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1030 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1031 && !disjointTypes(aLow.allparams(), highSub.allparams())
1032 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1033 if (upcast ? giveWarning(a, b) :
1034 giveWarning(b, a))
1035 warnStack.head.warnUnchecked();
1036 return true;
1037 }
1038 }
1039 if (isReifiable(s))
1040 return isSubtypeUnchecked(a, b);
1041 else
1042 return isSubtypeUnchecked(a, b, warnStack.head);
1043 }
1045 // Sidecast
1046 if (s.tag == CLASS) {
1047 if ((s.tsym.flags() & INTERFACE) != 0) {
1048 return ((t.tsym.flags() & FINAL) == 0)
1049 ? sideCast(t, s, warnStack.head)
1050 : sideCastFinal(t, s, warnStack.head);
1051 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1052 return ((s.tsym.flags() & FINAL) == 0)
1053 ? sideCast(t, s, warnStack.head)
1054 : sideCastFinal(t, s, warnStack.head);
1055 } else {
1056 // unrelated class types
1057 return false;
1058 }
1059 }
1060 }
1061 return false;
1062 }
1064 @Override
1065 public Boolean visitArrayType(ArrayType t, Type s) {
1066 switch (s.tag) {
1067 case ERROR:
1068 case BOT:
1069 return true;
1070 case TYPEVAR:
1071 if (isCastable(s, t, Warner.noWarnings)) {
1072 warnStack.head.warnUnchecked();
1073 return true;
1074 } else {
1075 return false;
1076 }
1077 case CLASS:
1078 return isSubtype(t, s);
1079 case ARRAY:
1080 if (elemtype(t).tag <= lastBaseTag) {
1081 return elemtype(t).tag == elemtype(s).tag;
1082 } else {
1083 return visit(elemtype(t), elemtype(s));
1084 }
1085 default:
1086 return false;
1087 }
1088 }
1090 @Override
1091 public Boolean visitTypeVar(TypeVar t, Type s) {
1092 switch (s.tag) {
1093 case ERROR:
1094 case BOT:
1095 return true;
1096 case TYPEVAR:
1097 if (isSubtype(t, s)) {
1098 return true;
1099 } else if (isCastable(t.bound, s, Warner.noWarnings)) {
1100 warnStack.head.warnUnchecked();
1101 return true;
1102 } else {
1103 return false;
1104 }
1105 default:
1106 return isCastable(t.bound, s, warnStack.head);
1107 }
1108 }
1110 @Override
1111 public Boolean visitErrorType(ErrorType t, Type s) {
1112 return true;
1113 }
1114 };
1115 // </editor-fold>
1117 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1118 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1119 while (ts.tail != null && ss.tail != null) {
1120 if (disjointType(ts.head, ss.head)) return true;
1121 ts = ts.tail;
1122 ss = ss.tail;
1123 }
1124 return false;
1125 }
1127 /**
1128 * Two types or wildcards are considered disjoint if it can be
1129 * proven that no type can be contained in both. It is
1130 * conservative in that it is allowed to say that two types are
1131 * not disjoint, even though they actually are.
1132 *
1133 * The type C<X> is castable to C<Y> exactly if X and Y are not
1134 * disjoint.
1135 */
1136 public boolean disjointType(Type t, Type s) {
1137 return disjointType.visit(t, s);
1138 }
1139 // where
1140 private TypeRelation disjointType = new TypeRelation() {
1142 private Set<TypePair> cache = new HashSet<TypePair>();
1144 public Boolean visitType(Type t, Type s) {
1145 if (s.tag == WILDCARD)
1146 return visit(s, t);
1147 else
1148 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1149 }
1151 private boolean isCastableRecursive(Type t, Type s) {
1152 TypePair pair = new TypePair(t, s);
1153 if (cache.add(pair)) {
1154 try {
1155 return Types.this.isCastable(t, s);
1156 } finally {
1157 cache.remove(pair);
1158 }
1159 } else {
1160 return true;
1161 }
1162 }
1164 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1165 TypePair pair = new TypePair(t, s);
1166 if (cache.add(pair)) {
1167 try {
1168 return Types.this.notSoftSubtype(t, s);
1169 } finally {
1170 cache.remove(pair);
1171 }
1172 } else {
1173 return false;
1174 }
1175 }
1177 @Override
1178 public Boolean visitWildcardType(WildcardType t, Type s) {
1179 if (t.isUnbound())
1180 return false;
1182 if (s.tag != WILDCARD) {
1183 if (t.isExtendsBound())
1184 return notSoftSubtypeRecursive(s, t.type);
1185 else // isSuperBound()
1186 return notSoftSubtypeRecursive(t.type, s);
1187 }
1189 if (s.isUnbound())
1190 return false;
1192 if (t.isExtendsBound()) {
1193 if (s.isExtendsBound())
1194 return !isCastableRecursive(t.type, upperBound(s));
1195 else if (s.isSuperBound())
1196 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1197 } else if (t.isSuperBound()) {
1198 if (s.isExtendsBound())
1199 return notSoftSubtypeRecursive(t.type, upperBound(s));
1200 }
1201 return false;
1202 }
1203 };
1204 // </editor-fold>
1206 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1207 /**
1208 * Returns the lower bounds of the formals of a method.
1209 */
1210 public List<Type> lowerBoundArgtypes(Type t) {
1211 return map(t.getParameterTypes(), lowerBoundMapping);
1212 }
1213 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1214 public Type apply(Type t) {
1215 return lowerBound(t);
1216 }
1217 };
1218 // </editor-fold>
1220 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1221 /**
1222 * This relation answers the question: is impossible that
1223 * something of type `t' can be a subtype of `s'? This is
1224 * different from the question "is `t' not a subtype of `s'?"
1225 * when type variables are involved: Integer is not a subtype of T
1226 * where <T extends Number> but it is not true that Integer cannot
1227 * possibly be a subtype of T.
1228 */
1229 public boolean notSoftSubtype(Type t, Type s) {
1230 if (t == s) return false;
1231 if (t.tag == TYPEVAR) {
1232 TypeVar tv = (TypeVar) t;
1233 if (s.tag == TYPEVAR)
1234 s = s.getUpperBound();
1235 return !isCastable(tv.bound,
1236 s,
1237 Warner.noWarnings);
1238 }
1239 if (s.tag != WILDCARD)
1240 s = upperBound(s);
1241 if (s.tag == TYPEVAR)
1242 s = s.getUpperBound();
1244 return !isSubtype(t, s);
1245 }
1246 // </editor-fold>
1248 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1249 public boolean isReifiable(Type t) {
1250 return isReifiable.visit(t);
1251 }
1252 // where
1253 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1255 public Boolean visitType(Type t, Void ignored) {
1256 return true;
1257 }
1259 @Override
1260 public Boolean visitClassType(ClassType t, Void ignored) {
1261 if (t.isCompound())
1262 return false;
1263 else {
1264 if (!t.isParameterized())
1265 return true;
1267 for (Type param : t.allparams()) {
1268 if (!param.isUnbound())
1269 return false;
1270 }
1271 return true;
1272 }
1273 }
1275 @Override
1276 public Boolean visitArrayType(ArrayType t, Void ignored) {
1277 return visit(t.elemtype);
1278 }
1280 @Override
1281 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1282 return false;
1283 }
1284 };
1285 // </editor-fold>
1287 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1288 public boolean isArray(Type t) {
1289 while (t.tag == WILDCARD)
1290 t = upperBound(t);
1291 return t.tag == ARRAY;
1292 }
1294 /**
1295 * The element type of an array.
1296 */
1297 public Type elemtype(Type t) {
1298 switch (t.tag) {
1299 case WILDCARD:
1300 return elemtype(upperBound(t));
1301 case ARRAY:
1302 return ((ArrayType)t).elemtype;
1303 case FORALL:
1304 return elemtype(((ForAll)t).qtype);
1305 case ERROR:
1306 return t;
1307 default:
1308 return null;
1309 }
1310 }
1312 /**
1313 * Mapping to take element type of an arraytype
1314 */
1315 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1316 public Type apply(Type t) { return elemtype(t); }
1317 };
1319 /**
1320 * The number of dimensions of an array type.
1321 */
1322 public int dimensions(Type t) {
1323 int result = 0;
1324 while (t.tag == ARRAY) {
1325 result++;
1326 t = elemtype(t);
1327 }
1328 return result;
1329 }
1330 // </editor-fold>
1332 // <editor-fold defaultstate="collapsed" desc="asSuper">
1333 /**
1334 * Return the (most specific) base type of t that starts with the
1335 * given symbol. If none exists, return null.
1336 *
1337 * @param t a type
1338 * @param sym a symbol
1339 */
1340 public Type asSuper(Type t, Symbol sym) {
1341 return asSuper.visit(t, sym);
1342 }
1343 // where
1344 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1346 public Type visitType(Type t, Symbol sym) {
1347 return null;
1348 }
1350 @Override
1351 public Type visitClassType(ClassType t, Symbol sym) {
1352 if (t.tsym == sym)
1353 return t;
1355 Type st = supertype(t);
1356 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1357 Type x = asSuper(st, sym);
1358 if (x != null)
1359 return x;
1360 }
1361 if ((sym.flags() & INTERFACE) != 0) {
1362 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1363 Type x = asSuper(l.head, sym);
1364 if (x != null)
1365 return x;
1366 }
1367 }
1368 return null;
1369 }
1371 @Override
1372 public Type visitArrayType(ArrayType t, Symbol sym) {
1373 return isSubtype(t, sym.type) ? sym.type : null;
1374 }
1376 @Override
1377 public Type visitTypeVar(TypeVar t, Symbol sym) {
1378 if (t.tsym == sym)
1379 return t;
1380 else
1381 return asSuper(t.bound, sym);
1382 }
1384 @Override
1385 public Type visitErrorType(ErrorType t, Symbol sym) {
1386 return t;
1387 }
1388 };
1390 /**
1391 * Return the base type of t or any of its outer types that starts
1392 * with the given symbol. If none exists, return null.
1393 *
1394 * @param t a type
1395 * @param sym a symbol
1396 */
1397 public Type asOuterSuper(Type t, Symbol sym) {
1398 switch (t.tag) {
1399 case CLASS:
1400 do {
1401 Type s = asSuper(t, sym);
1402 if (s != null) return s;
1403 t = t.getEnclosingType();
1404 } while (t.tag == CLASS);
1405 return null;
1406 case ARRAY:
1407 return isSubtype(t, sym.type) ? sym.type : null;
1408 case TYPEVAR:
1409 return asSuper(t, sym);
1410 case ERROR:
1411 return t;
1412 default:
1413 return null;
1414 }
1415 }
1417 /**
1418 * Return the base type of t or any of its enclosing types that
1419 * starts with the given symbol. If none exists, return null.
1420 *
1421 * @param t a type
1422 * @param sym a symbol
1423 */
1424 public Type asEnclosingSuper(Type t, Symbol sym) {
1425 switch (t.tag) {
1426 case CLASS:
1427 do {
1428 Type s = asSuper(t, sym);
1429 if (s != null) return s;
1430 Type outer = t.getEnclosingType();
1431 t = (outer.tag == CLASS) ? outer :
1432 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1433 Type.noType;
1434 } while (t.tag == CLASS);
1435 return null;
1436 case ARRAY:
1437 return isSubtype(t, sym.type) ? sym.type : null;
1438 case TYPEVAR:
1439 return asSuper(t, sym);
1440 case ERROR:
1441 return t;
1442 default:
1443 return null;
1444 }
1445 }
1446 // </editor-fold>
1448 // <editor-fold defaultstate="collapsed" desc="memberType">
1449 /**
1450 * The type of given symbol, seen as a member of t.
1451 *
1452 * @param t a type
1453 * @param sym a symbol
1454 */
1455 public Type memberType(Type t, Symbol sym) {
1456 return (sym.flags() & STATIC) != 0
1457 ? sym.type
1458 : memberType.visit(t, sym);
1459 }
1460 // where
1461 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1463 public Type visitType(Type t, Symbol sym) {
1464 return sym.type;
1465 }
1467 @Override
1468 public Type visitWildcardType(WildcardType t, Symbol sym) {
1469 return memberType(upperBound(t), sym);
1470 }
1472 @Override
1473 public Type visitClassType(ClassType t, Symbol sym) {
1474 Symbol owner = sym.owner;
1475 long flags = sym.flags();
1476 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1477 Type base = asOuterSuper(t, owner);
1478 //if t is an intersection type T = CT & I1 & I2 ... & In
1479 //its supertypes CT, I1, ... In might contain wildcards
1480 //so we need to go through capture conversion
1481 base = t.isCompound() ? capture(base) : base;
1482 if (base != null) {
1483 List<Type> ownerParams = owner.type.allparams();
1484 List<Type> baseParams = base.allparams();
1485 if (ownerParams.nonEmpty()) {
1486 if (baseParams.isEmpty()) {
1487 // then base is a raw type
1488 return erasure(sym.type);
1489 } else {
1490 return subst(sym.type, ownerParams, baseParams);
1491 }
1492 }
1493 }
1494 }
1495 return sym.type;
1496 }
1498 @Override
1499 public Type visitTypeVar(TypeVar t, Symbol sym) {
1500 return memberType(t.bound, sym);
1501 }
1503 @Override
1504 public Type visitErrorType(ErrorType t, Symbol sym) {
1505 return t;
1506 }
1507 };
1508 // </editor-fold>
1510 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1511 public boolean isAssignable(Type t, Type s) {
1512 return isAssignable(t, s, Warner.noWarnings);
1513 }
1515 /**
1516 * Is t assignable to s?<br>
1517 * Equivalent to subtype except for constant values and raw
1518 * types.<br>
1519 * (not defined for Method and ForAll types)
1520 */
1521 public boolean isAssignable(Type t, Type s, Warner warn) {
1522 if (t.tag == ERROR)
1523 return true;
1524 if (t.tag <= INT && t.constValue() != null) {
1525 int value = ((Number)t.constValue()).intValue();
1526 switch (s.tag) {
1527 case BYTE:
1528 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1529 return true;
1530 break;
1531 case CHAR:
1532 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1533 return true;
1534 break;
1535 case SHORT:
1536 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1537 return true;
1538 break;
1539 case INT:
1540 return true;
1541 case CLASS:
1542 switch (unboxedType(s).tag) {
1543 case BYTE:
1544 case CHAR:
1545 case SHORT:
1546 return isAssignable(t, unboxedType(s), warn);
1547 }
1548 break;
1549 }
1550 }
1551 return isConvertible(t, s, warn);
1552 }
1553 // </editor-fold>
1555 // <editor-fold defaultstate="collapsed" desc="erasure">
1556 /**
1557 * The erasure of t {@code |t|} -- the type that results when all
1558 * type parameters in t are deleted.
1559 */
1560 public Type erasure(Type t) {
1561 return erasure(t, false);
1562 }
1563 //where
1564 private Type erasure(Type t, boolean recurse) {
1565 if (t.tag <= lastBaseTag)
1566 return t; /* fast special case */
1567 else
1568 return erasure.visit(t, recurse);
1569 }
1570 // where
1571 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
1572 public Type visitType(Type t, Boolean recurse) {
1573 if (t.tag <= lastBaseTag)
1574 return t; /*fast special case*/
1575 else
1576 return t.map(recurse ? erasureRecFun : erasureFun);
1577 }
1579 @Override
1580 public Type visitWildcardType(WildcardType t, Boolean recurse) {
1581 return erasure(upperBound(t), recurse);
1582 }
1584 @Override
1585 public Type visitClassType(ClassType t, Boolean recurse) {
1586 Type erased = t.tsym.erasure(Types.this);
1587 if (recurse) {
1588 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
1589 }
1590 return erased;
1591 }
1593 @Override
1594 public Type visitTypeVar(TypeVar t, Boolean recurse) {
1595 return erasure(t.bound, recurse);
1596 }
1598 @Override
1599 public Type visitErrorType(ErrorType t, Boolean recurse) {
1600 return t;
1601 }
1602 };
1604 private Mapping erasureFun = new Mapping ("erasure") {
1605 public Type apply(Type t) { return erasure(t); }
1606 };
1608 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
1609 public Type apply(Type t) { return erasureRecursive(t); }
1610 };
1612 public List<Type> erasure(List<Type> ts) {
1613 return Type.map(ts, erasureFun);
1614 }
1616 public Type erasureRecursive(Type t) {
1617 return erasure(t, true);
1618 }
1620 public List<Type> erasureRecursive(List<Type> ts) {
1621 return Type.map(ts, erasureRecFun);
1622 }
1623 // </editor-fold>
1625 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
1626 /**
1627 * Make a compound type from non-empty list of types
1628 *
1629 * @param bounds the types from which the compound type is formed
1630 * @param supertype is objectType if all bounds are interfaces,
1631 * null otherwise.
1632 */
1633 public Type makeCompoundType(List<Type> bounds,
1634 Type supertype) {
1635 ClassSymbol bc =
1636 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
1637 Type.moreInfo
1638 ? names.fromString(bounds.toString())
1639 : names.empty,
1640 syms.noSymbol);
1641 if (bounds.head.tag == TYPEVAR)
1642 // error condition, recover
1643 bc.erasure_field = syms.objectType;
1644 else
1645 bc.erasure_field = erasure(bounds.head);
1646 bc.members_field = new Scope(bc);
1647 ClassType bt = (ClassType)bc.type;
1648 bt.allparams_field = List.nil();
1649 if (supertype != null) {
1650 bt.supertype_field = supertype;
1651 bt.interfaces_field = bounds;
1652 } else {
1653 bt.supertype_field = bounds.head;
1654 bt.interfaces_field = bounds.tail;
1655 }
1656 assert bt.supertype_field.tsym.completer != null
1657 || !bt.supertype_field.isInterface()
1658 : bt.supertype_field;
1659 return bt;
1660 }
1662 /**
1663 * Same as {@link #makeCompoundType(List,Type)}, except that the
1664 * second parameter is computed directly. Note that this might
1665 * cause a symbol completion. Hence, this version of
1666 * makeCompoundType may not be called during a classfile read.
1667 */
1668 public Type makeCompoundType(List<Type> bounds) {
1669 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1670 supertype(bounds.head) : null;
1671 return makeCompoundType(bounds, supertype);
1672 }
1674 /**
1675 * A convenience wrapper for {@link #makeCompoundType(List)}; the
1676 * arguments are converted to a list and passed to the other
1677 * method. Note that this might cause a symbol completion.
1678 * Hence, this version of makeCompoundType may not be called
1679 * during a classfile read.
1680 */
1681 public Type makeCompoundType(Type bound1, Type bound2) {
1682 return makeCompoundType(List.of(bound1, bound2));
1683 }
1684 // </editor-fold>
1686 // <editor-fold defaultstate="collapsed" desc="supertype">
1687 public Type supertype(Type t) {
1688 return supertype.visit(t);
1689 }
1690 // where
1691 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
1693 public Type visitType(Type t, Void ignored) {
1694 // A note on wildcards: there is no good way to
1695 // determine a supertype for a super bounded wildcard.
1696 return null;
1697 }
1699 @Override
1700 public Type visitClassType(ClassType t, Void ignored) {
1701 if (t.supertype_field == null) {
1702 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
1703 // An interface has no superclass; its supertype is Object.
1704 if (t.isInterface())
1705 supertype = ((ClassType)t.tsym.type).supertype_field;
1706 if (t.supertype_field == null) {
1707 List<Type> actuals = classBound(t).allparams();
1708 List<Type> formals = t.tsym.type.allparams();
1709 if (t.hasErasedSupertypes()) {
1710 t.supertype_field = erasureRecursive(supertype);
1711 } else if (formals.nonEmpty()) {
1712 t.supertype_field = subst(supertype, formals, actuals);
1713 }
1714 else {
1715 t.supertype_field = supertype;
1716 }
1717 }
1718 }
1719 return t.supertype_field;
1720 }
1722 /**
1723 * The supertype is always a class type. If the type
1724 * variable's bounds start with a class type, this is also
1725 * the supertype. Otherwise, the supertype is
1726 * java.lang.Object.
1727 */
1728 @Override
1729 public Type visitTypeVar(TypeVar t, Void ignored) {
1730 if (t.bound.tag == TYPEVAR ||
1731 (!t.bound.isCompound() && !t.bound.isInterface())) {
1732 return t.bound;
1733 } else {
1734 return supertype(t.bound);
1735 }
1736 }
1738 @Override
1739 public Type visitArrayType(ArrayType t, Void ignored) {
1740 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
1741 return arraySuperType();
1742 else
1743 return new ArrayType(supertype(t.elemtype), t.tsym);
1744 }
1746 @Override
1747 public Type visitErrorType(ErrorType t, Void ignored) {
1748 return t;
1749 }
1750 };
1751 // </editor-fold>
1753 // <editor-fold defaultstate="collapsed" desc="interfaces">
1754 /**
1755 * Return the interfaces implemented by this class.
1756 */
1757 public List<Type> interfaces(Type t) {
1758 return interfaces.visit(t);
1759 }
1760 // where
1761 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
1763 public List<Type> visitType(Type t, Void ignored) {
1764 return List.nil();
1765 }
1767 @Override
1768 public List<Type> visitClassType(ClassType t, Void ignored) {
1769 if (t.interfaces_field == null) {
1770 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
1771 if (t.interfaces_field == null) {
1772 // If t.interfaces_field is null, then t must
1773 // be a parameterized type (not to be confused
1774 // with a generic type declaration).
1775 // Terminology:
1776 // Parameterized type: List<String>
1777 // Generic type declaration: class List<E> { ... }
1778 // So t corresponds to List<String> and
1779 // t.tsym.type corresponds to List<E>.
1780 // The reason t must be parameterized type is
1781 // that completion will happen as a side
1782 // effect of calling
1783 // ClassSymbol.getInterfaces. Since
1784 // t.interfaces_field is null after
1785 // completion, we can assume that t is not the
1786 // type of a class/interface declaration.
1787 assert t != t.tsym.type : t.toString();
1788 List<Type> actuals = t.allparams();
1789 List<Type> formals = t.tsym.type.allparams();
1790 if (t.hasErasedSupertypes()) {
1791 t.interfaces_field = erasureRecursive(interfaces);
1792 } else if (formals.nonEmpty()) {
1793 t.interfaces_field =
1794 upperBounds(subst(interfaces, formals, actuals));
1795 }
1796 else {
1797 t.interfaces_field = interfaces;
1798 }
1799 }
1800 }
1801 return t.interfaces_field;
1802 }
1804 @Override
1805 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
1806 if (t.bound.isCompound())
1807 return interfaces(t.bound);
1809 if (t.bound.isInterface())
1810 return List.of(t.bound);
1812 return List.nil();
1813 }
1814 };
1815 // </editor-fold>
1817 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
1818 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
1820 public boolean isDerivedRaw(Type t) {
1821 Boolean result = isDerivedRawCache.get(t);
1822 if (result == null) {
1823 result = isDerivedRawInternal(t);
1824 isDerivedRawCache.put(t, result);
1825 }
1826 return result;
1827 }
1829 public boolean isDerivedRawInternal(Type t) {
1830 if (t.isErroneous())
1831 return false;
1832 return
1833 t.isRaw() ||
1834 supertype(t) != null && isDerivedRaw(supertype(t)) ||
1835 isDerivedRaw(interfaces(t));
1836 }
1838 public boolean isDerivedRaw(List<Type> ts) {
1839 List<Type> l = ts;
1840 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
1841 return l.nonEmpty();
1842 }
1843 // </editor-fold>
1845 // <editor-fold defaultstate="collapsed" desc="setBounds">
1846 /**
1847 * Set the bounds field of the given type variable to reflect a
1848 * (possibly multiple) list of bounds.
1849 * @param t a type variable
1850 * @param bounds the bounds, must be nonempty
1851 * @param supertype is objectType if all bounds are interfaces,
1852 * null otherwise.
1853 */
1854 public void setBounds(TypeVar t, List<Type> bounds, Type supertype) {
1855 if (bounds.tail.isEmpty())
1856 t.bound = bounds.head;
1857 else
1858 t.bound = makeCompoundType(bounds, supertype);
1859 t.rank_field = -1;
1860 }
1862 /**
1863 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
1864 * third parameter is computed directly, as follows: if all
1865 * all bounds are interface types, the computed supertype is Object,
1866 * otherwise the supertype is simply left null (in this case, the supertype
1867 * is assumed to be the head of the bound list passed as second argument).
1868 * Note that this check might cause a symbol completion. Hence, this version of
1869 * setBounds may not be called during a classfile read.
1870 */
1871 public void setBounds(TypeVar t, List<Type> bounds) {
1872 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1873 syms.objectType : null;
1874 setBounds(t, bounds, supertype);
1875 t.rank_field = -1;
1876 }
1877 // </editor-fold>
1879 // <editor-fold defaultstate="collapsed" desc="getBounds">
1880 /**
1881 * Return list of bounds of the given type variable.
1882 */
1883 public List<Type> getBounds(TypeVar t) {
1884 if (t.bound.isErroneous() || !t.bound.isCompound())
1885 return List.of(t.bound);
1886 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
1887 return interfaces(t).prepend(supertype(t));
1888 else
1889 // No superclass was given in bounds.
1890 // In this case, supertype is Object, erasure is first interface.
1891 return interfaces(t);
1892 }
1893 // </editor-fold>
1895 // <editor-fold defaultstate="collapsed" desc="classBound">
1896 /**
1897 * If the given type is a (possibly selected) type variable,
1898 * return the bounding class of this type, otherwise return the
1899 * type itself.
1900 */
1901 public Type classBound(Type t) {
1902 return classBound.visit(t);
1903 }
1904 // where
1905 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
1907 public Type visitType(Type t, Void ignored) {
1908 return t;
1909 }
1911 @Override
1912 public Type visitClassType(ClassType t, Void ignored) {
1913 Type outer1 = classBound(t.getEnclosingType());
1914 if (outer1 != t.getEnclosingType())
1915 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
1916 else
1917 return t;
1918 }
1920 @Override
1921 public Type visitTypeVar(TypeVar t, Void ignored) {
1922 return classBound(supertype(t));
1923 }
1925 @Override
1926 public Type visitErrorType(ErrorType t, Void ignored) {
1927 return t;
1928 }
1929 };
1930 // </editor-fold>
1932 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
1933 /**
1934 * Returns true iff the first signature is a <em>sub
1935 * signature</em> of the other. This is <b>not</b> an equivalence
1936 * relation.
1937 *
1938 * @see "The Java Language Specification, Third Ed. (8.4.2)."
1939 * @see #overrideEquivalent(Type t, Type s)
1940 * @param t first signature (possibly raw).
1941 * @param s second signature (could be subjected to erasure).
1942 * @return true if t is a sub signature of s.
1943 */
1944 public boolean isSubSignature(Type t, Type s) {
1945 return hasSameArgs(t, s) || hasSameArgs(t, erasure(s));
1946 }
1948 /**
1949 * Returns true iff these signatures are related by <em>override
1950 * equivalence</em>. This is the natural extension of
1951 * isSubSignature to an equivalence relation.
1952 *
1953 * @see "The Java Language Specification, Third Ed. (8.4.2)."
1954 * @see #isSubSignature(Type t, Type s)
1955 * @param t a signature (possible raw, could be subjected to
1956 * erasure).
1957 * @param s a signature (possible raw, could be subjected to
1958 * erasure).
1959 * @return true if either argument is a sub signature of the other.
1960 */
1961 public boolean overrideEquivalent(Type t, Type s) {
1962 return hasSameArgs(t, s) ||
1963 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
1964 }
1966 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, MethodSymbol>>> implCache_check =
1967 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, MethodSymbol>>>();
1969 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, MethodSymbol>>> implCache_nocheck =
1970 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, MethodSymbol>>>();
1972 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, Types types, boolean checkResult) {
1973 Map<MethodSymbol, SoftReference<Map<TypeSymbol, MethodSymbol>>> implCache = checkResult ?
1974 implCache_check : implCache_nocheck;
1975 SoftReference<Map<TypeSymbol, MethodSymbol>> ref_cache = implCache.get(ms);
1976 Map<TypeSymbol, MethodSymbol> cache = ref_cache != null ? ref_cache.get() : null;
1977 if (cache == null) {
1978 cache = new HashMap<TypeSymbol, MethodSymbol>();
1979 implCache.put(ms, new SoftReference<Map<TypeSymbol, MethodSymbol>>(cache));
1980 }
1981 MethodSymbol impl = cache.get(origin);
1982 if (impl == null) {
1983 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = types.supertype(t)) {
1984 while (t.tag == TYPEVAR)
1985 t = t.getUpperBound();
1986 TypeSymbol c = t.tsym;
1987 for (Scope.Entry e = c.members().lookup(ms.name);
1988 e.scope != null;
1989 e = e.next()) {
1990 if (e.sym.kind == Kinds.MTH) {
1991 MethodSymbol m = (MethodSymbol) e.sym;
1992 if (m.overrides(ms, origin, types, checkResult) &&
1993 (m.flags() & SYNTHETIC) == 0) {
1994 impl = m;
1995 cache.put(origin, m);
1996 return impl;
1997 }
1998 }
1999 }
2000 }
2001 }
2002 return impl;
2003 }
2005 /**
2006 * Does t have the same arguments as s? It is assumed that both
2007 * types are (possibly polymorphic) method types. Monomorphic
2008 * method types "have the same arguments", if their argument lists
2009 * are equal. Polymorphic method types "have the same arguments",
2010 * if they have the same arguments after renaming all type
2011 * variables of one to corresponding type variables in the other,
2012 * where correspondence is by position in the type parameter list.
2013 */
2014 public boolean hasSameArgs(Type t, Type s) {
2015 return hasSameArgs.visit(t, s);
2016 }
2017 // where
2018 private TypeRelation hasSameArgs = new TypeRelation() {
2020 public Boolean visitType(Type t, Type s) {
2021 throw new AssertionError();
2022 }
2024 @Override
2025 public Boolean visitMethodType(MethodType t, Type s) {
2026 return s.tag == METHOD
2027 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2028 }
2030 @Override
2031 public Boolean visitForAll(ForAll t, Type s) {
2032 if (s.tag != FORALL)
2033 return false;
2035 ForAll forAll = (ForAll)s;
2036 return hasSameBounds(t, forAll)
2037 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2038 }
2040 @Override
2041 public Boolean visitErrorType(ErrorType t, Type s) {
2042 return false;
2043 }
2044 };
2045 // </editor-fold>
2047 // <editor-fold defaultstate="collapsed" desc="subst">
2048 public List<Type> subst(List<Type> ts,
2049 List<Type> from,
2050 List<Type> to) {
2051 return new Subst(from, to).subst(ts);
2052 }
2054 /**
2055 * Substitute all occurrences of a type in `from' with the
2056 * corresponding type in `to' in 't'. Match lists `from' and `to'
2057 * from the right: If lists have different length, discard leading
2058 * elements of the longer list.
2059 */
2060 public Type subst(Type t, List<Type> from, List<Type> to) {
2061 return new Subst(from, to).subst(t);
2062 }
2064 private class Subst extends UnaryVisitor<Type> {
2065 List<Type> from;
2066 List<Type> to;
2068 public Subst(List<Type> from, List<Type> to) {
2069 int fromLength = from.length();
2070 int toLength = to.length();
2071 while (fromLength > toLength) {
2072 fromLength--;
2073 from = from.tail;
2074 }
2075 while (fromLength < toLength) {
2076 toLength--;
2077 to = to.tail;
2078 }
2079 this.from = from;
2080 this.to = to;
2081 }
2083 Type subst(Type t) {
2084 if (from.tail == null)
2085 return t;
2086 else
2087 return visit(t);
2088 }
2090 List<Type> subst(List<Type> ts) {
2091 if (from.tail == null)
2092 return ts;
2093 boolean wild = false;
2094 if (ts.nonEmpty() && from.nonEmpty()) {
2095 Type head1 = subst(ts.head);
2096 List<Type> tail1 = subst(ts.tail);
2097 if (head1 != ts.head || tail1 != ts.tail)
2098 return tail1.prepend(head1);
2099 }
2100 return ts;
2101 }
2103 public Type visitType(Type t, Void ignored) {
2104 return t;
2105 }
2107 @Override
2108 public Type visitMethodType(MethodType t, Void ignored) {
2109 List<Type> argtypes = subst(t.argtypes);
2110 Type restype = subst(t.restype);
2111 List<Type> thrown = subst(t.thrown);
2112 if (argtypes == t.argtypes &&
2113 restype == t.restype &&
2114 thrown == t.thrown)
2115 return t;
2116 else
2117 return new MethodType(argtypes, restype, thrown, t.tsym);
2118 }
2120 @Override
2121 public Type visitTypeVar(TypeVar t, Void ignored) {
2122 for (List<Type> from = this.from, to = this.to;
2123 from.nonEmpty();
2124 from = from.tail, to = to.tail) {
2125 if (t == from.head) {
2126 return to.head.withTypeVar(t);
2127 }
2128 }
2129 return t;
2130 }
2132 @Override
2133 public Type visitClassType(ClassType t, Void ignored) {
2134 if (!t.isCompound()) {
2135 List<Type> typarams = t.getTypeArguments();
2136 List<Type> typarams1 = subst(typarams);
2137 Type outer = t.getEnclosingType();
2138 Type outer1 = subst(outer);
2139 if (typarams1 == typarams && outer1 == outer)
2140 return t;
2141 else
2142 return new ClassType(outer1, typarams1, t.tsym);
2143 } else {
2144 Type st = subst(supertype(t));
2145 List<Type> is = upperBounds(subst(interfaces(t)));
2146 if (st == supertype(t) && is == interfaces(t))
2147 return t;
2148 else
2149 return makeCompoundType(is.prepend(st));
2150 }
2151 }
2153 @Override
2154 public Type visitWildcardType(WildcardType t, Void ignored) {
2155 Type bound = t.type;
2156 if (t.kind != BoundKind.UNBOUND)
2157 bound = subst(bound);
2158 if (bound == t.type) {
2159 return t;
2160 } else {
2161 if (t.isExtendsBound() && bound.isExtendsBound())
2162 bound = upperBound(bound);
2163 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2164 }
2165 }
2167 @Override
2168 public Type visitArrayType(ArrayType t, Void ignored) {
2169 Type elemtype = subst(t.elemtype);
2170 if (elemtype == t.elemtype)
2171 return t;
2172 else
2173 return new ArrayType(upperBound(elemtype), t.tsym);
2174 }
2176 @Override
2177 public Type visitForAll(ForAll t, Void ignored) {
2178 List<Type> tvars1 = substBounds(t.tvars, from, to);
2179 Type qtype1 = subst(t.qtype);
2180 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2181 return t;
2182 } else if (tvars1 == t.tvars) {
2183 return new ForAll(tvars1, qtype1);
2184 } else {
2185 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2186 }
2187 }
2189 @Override
2190 public Type visitErrorType(ErrorType t, Void ignored) {
2191 return t;
2192 }
2193 }
2195 public List<Type> substBounds(List<Type> tvars,
2196 List<Type> from,
2197 List<Type> to) {
2198 if (tvars.isEmpty())
2199 return tvars;
2200 ListBuffer<Type> newBoundsBuf = lb();
2201 boolean changed = false;
2202 // calculate new bounds
2203 for (Type t : tvars) {
2204 TypeVar tv = (TypeVar) t;
2205 Type bound = subst(tv.bound, from, to);
2206 if (bound != tv.bound)
2207 changed = true;
2208 newBoundsBuf.append(bound);
2209 }
2210 if (!changed)
2211 return tvars;
2212 ListBuffer<Type> newTvars = lb();
2213 // create new type variables without bounds
2214 for (Type t : tvars) {
2215 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2216 }
2217 // the new bounds should use the new type variables in place
2218 // of the old
2219 List<Type> newBounds = newBoundsBuf.toList();
2220 from = tvars;
2221 to = newTvars.toList();
2222 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2223 newBounds.head = subst(newBounds.head, from, to);
2224 }
2225 newBounds = newBoundsBuf.toList();
2226 // set the bounds of new type variables to the new bounds
2227 for (Type t : newTvars.toList()) {
2228 TypeVar tv = (TypeVar) t;
2229 tv.bound = newBounds.head;
2230 newBounds = newBounds.tail;
2231 }
2232 return newTvars.toList();
2233 }
2235 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2236 Type bound1 = subst(t.bound, from, to);
2237 if (bound1 == t.bound)
2238 return t;
2239 else {
2240 // create new type variable without bounds
2241 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2242 // the new bound should use the new type variable in place
2243 // of the old
2244 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2245 return tv;
2246 }
2247 }
2248 // </editor-fold>
2250 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2251 /**
2252 * Does t have the same bounds for quantified variables as s?
2253 */
2254 boolean hasSameBounds(ForAll t, ForAll s) {
2255 List<Type> l1 = t.tvars;
2256 List<Type> l2 = s.tvars;
2257 while (l1.nonEmpty() && l2.nonEmpty() &&
2258 isSameType(l1.head.getUpperBound(),
2259 subst(l2.head.getUpperBound(),
2260 s.tvars,
2261 t.tvars))) {
2262 l1 = l1.tail;
2263 l2 = l2.tail;
2264 }
2265 return l1.isEmpty() && l2.isEmpty();
2266 }
2267 // </editor-fold>
2269 // <editor-fold defaultstate="collapsed" desc="newInstances">
2270 /** Create new vector of type variables from list of variables
2271 * changing all recursive bounds from old to new list.
2272 */
2273 public List<Type> newInstances(List<Type> tvars) {
2274 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2275 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2276 TypeVar tv = (TypeVar) l.head;
2277 tv.bound = subst(tv.bound, tvars, tvars1);
2278 }
2279 return tvars1;
2280 }
2281 static private Mapping newInstanceFun = new Mapping("newInstanceFun") {
2282 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2283 };
2284 // </editor-fold>
2286 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2287 public Type createErrorType(Type originalType) {
2288 return new ErrorType(originalType, syms.errSymbol);
2289 }
2291 public Type createErrorType(ClassSymbol c, Type originalType) {
2292 return new ErrorType(c, originalType);
2293 }
2295 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
2296 return new ErrorType(name, container, originalType);
2297 }
2298 // </editor-fold>
2300 // <editor-fold defaultstate="collapsed" desc="rank">
2301 /**
2302 * The rank of a class is the length of the longest path between
2303 * the class and java.lang.Object in the class inheritance
2304 * graph. Undefined for all but reference types.
2305 */
2306 public int rank(Type t) {
2307 switch(t.tag) {
2308 case CLASS: {
2309 ClassType cls = (ClassType)t;
2310 if (cls.rank_field < 0) {
2311 Name fullname = cls.tsym.getQualifiedName();
2312 if (fullname == names.java_lang_Object)
2313 cls.rank_field = 0;
2314 else {
2315 int r = rank(supertype(cls));
2316 for (List<Type> l = interfaces(cls);
2317 l.nonEmpty();
2318 l = l.tail) {
2319 if (rank(l.head) > r)
2320 r = rank(l.head);
2321 }
2322 cls.rank_field = r + 1;
2323 }
2324 }
2325 return cls.rank_field;
2326 }
2327 case TYPEVAR: {
2328 TypeVar tvar = (TypeVar)t;
2329 if (tvar.rank_field < 0) {
2330 int r = rank(supertype(tvar));
2331 for (List<Type> l = interfaces(tvar);
2332 l.nonEmpty();
2333 l = l.tail) {
2334 if (rank(l.head) > r) r = rank(l.head);
2335 }
2336 tvar.rank_field = r + 1;
2337 }
2338 return tvar.rank_field;
2339 }
2340 case ERROR:
2341 return 0;
2342 default:
2343 throw new AssertionError();
2344 }
2345 }
2346 // </editor-fold>
2348 /**
2349 * Helper method for generating a string representation of a given type
2350 * accordingly to a given locale
2351 */
2352 public String toString(Type t, Locale locale) {
2353 return Printer.createStandardPrinter(messages).visit(t, locale);
2354 }
2356 /**
2357 * Helper method for generating a string representation of a given type
2358 * accordingly to a given locale
2359 */
2360 public String toString(Symbol t, Locale locale) {
2361 return Printer.createStandardPrinter(messages).visit(t, locale);
2362 }
2364 // <editor-fold defaultstate="collapsed" desc="toString">
2365 /**
2366 * This toString is slightly more descriptive than the one on Type.
2367 *
2368 * @deprecated Types.toString(Type t, Locale l) provides better support
2369 * for localization
2370 */
2371 @Deprecated
2372 public String toString(Type t) {
2373 if (t.tag == FORALL) {
2374 ForAll forAll = (ForAll)t;
2375 return typaramsString(forAll.tvars) + forAll.qtype;
2376 }
2377 return "" + t;
2378 }
2379 // where
2380 private String typaramsString(List<Type> tvars) {
2381 StringBuffer s = new StringBuffer();
2382 s.append('<');
2383 boolean first = true;
2384 for (Type t : tvars) {
2385 if (!first) s.append(", ");
2386 first = false;
2387 appendTyparamString(((TypeVar)t), s);
2388 }
2389 s.append('>');
2390 return s.toString();
2391 }
2392 private void appendTyparamString(TypeVar t, StringBuffer buf) {
2393 buf.append(t);
2394 if (t.bound == null ||
2395 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
2396 return;
2397 buf.append(" extends "); // Java syntax; no need for i18n
2398 Type bound = t.bound;
2399 if (!bound.isCompound()) {
2400 buf.append(bound);
2401 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
2402 buf.append(supertype(t));
2403 for (Type intf : interfaces(t)) {
2404 buf.append('&');
2405 buf.append(intf);
2406 }
2407 } else {
2408 // No superclass was given in bounds.
2409 // In this case, supertype is Object, erasure is first interface.
2410 boolean first = true;
2411 for (Type intf : interfaces(t)) {
2412 if (!first) buf.append('&');
2413 first = false;
2414 buf.append(intf);
2415 }
2416 }
2417 }
2418 // </editor-fold>
2420 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
2421 /**
2422 * A cache for closures.
2423 *
2424 * <p>A closure is a list of all the supertypes and interfaces of
2425 * a class or interface type, ordered by ClassSymbol.precedes
2426 * (that is, subclasses come first, arbitrary but fixed
2427 * otherwise).
2428 */
2429 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
2431 /**
2432 * Returns the closure of a class or interface type.
2433 */
2434 public List<Type> closure(Type t) {
2435 List<Type> cl = closureCache.get(t);
2436 if (cl == null) {
2437 Type st = supertype(t);
2438 if (!t.isCompound()) {
2439 if (st.tag == CLASS) {
2440 cl = insert(closure(st), t);
2441 } else if (st.tag == TYPEVAR) {
2442 cl = closure(st).prepend(t);
2443 } else {
2444 cl = List.of(t);
2445 }
2446 } else {
2447 cl = closure(supertype(t));
2448 }
2449 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
2450 cl = union(cl, closure(l.head));
2451 closureCache.put(t, cl);
2452 }
2453 return cl;
2454 }
2456 /**
2457 * Insert a type in a closure
2458 */
2459 public List<Type> insert(List<Type> cl, Type t) {
2460 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
2461 return cl.prepend(t);
2462 } else if (cl.head.tsym.precedes(t.tsym, this)) {
2463 return insert(cl.tail, t).prepend(cl.head);
2464 } else {
2465 return cl;
2466 }
2467 }
2469 /**
2470 * Form the union of two closures
2471 */
2472 public List<Type> union(List<Type> cl1, List<Type> cl2) {
2473 if (cl1.isEmpty()) {
2474 return cl2;
2475 } else if (cl2.isEmpty()) {
2476 return cl1;
2477 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
2478 return union(cl1.tail, cl2).prepend(cl1.head);
2479 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
2480 return union(cl1, cl2.tail).prepend(cl2.head);
2481 } else {
2482 return union(cl1.tail, cl2.tail).prepend(cl1.head);
2483 }
2484 }
2486 /**
2487 * Intersect two closures
2488 */
2489 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
2490 if (cl1 == cl2)
2491 return cl1;
2492 if (cl1.isEmpty() || cl2.isEmpty())
2493 return List.nil();
2494 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
2495 return intersect(cl1.tail, cl2);
2496 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
2497 return intersect(cl1, cl2.tail);
2498 if (isSameType(cl1.head, cl2.head))
2499 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
2500 if (cl1.head.tsym == cl2.head.tsym &&
2501 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
2502 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
2503 Type merge = merge(cl1.head,cl2.head);
2504 return intersect(cl1.tail, cl2.tail).prepend(merge);
2505 }
2506 if (cl1.head.isRaw() || cl2.head.isRaw())
2507 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
2508 }
2509 return intersect(cl1.tail, cl2.tail);
2510 }
2511 // where
2512 class TypePair {
2513 final Type t1;
2514 final Type t2;
2515 TypePair(Type t1, Type t2) {
2516 this.t1 = t1;
2517 this.t2 = t2;
2518 }
2519 @Override
2520 public int hashCode() {
2521 return 127 * Types.hashCode(t1) + Types.hashCode(t2);
2522 }
2523 @Override
2524 public boolean equals(Object obj) {
2525 if (!(obj instanceof TypePair))
2526 return false;
2527 TypePair typePair = (TypePair)obj;
2528 return isSameType(t1, typePair.t1)
2529 && isSameType(t2, typePair.t2);
2530 }
2531 }
2532 Set<TypePair> mergeCache = new HashSet<TypePair>();
2533 private Type merge(Type c1, Type c2) {
2534 ClassType class1 = (ClassType) c1;
2535 List<Type> act1 = class1.getTypeArguments();
2536 ClassType class2 = (ClassType) c2;
2537 List<Type> act2 = class2.getTypeArguments();
2538 ListBuffer<Type> merged = new ListBuffer<Type>();
2539 List<Type> typarams = class1.tsym.type.getTypeArguments();
2541 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
2542 if (containsType(act1.head, act2.head)) {
2543 merged.append(act1.head);
2544 } else if (containsType(act2.head, act1.head)) {
2545 merged.append(act2.head);
2546 } else {
2547 TypePair pair = new TypePair(c1, c2);
2548 Type m;
2549 if (mergeCache.add(pair)) {
2550 m = new WildcardType(lub(upperBound(act1.head),
2551 upperBound(act2.head)),
2552 BoundKind.EXTENDS,
2553 syms.boundClass);
2554 mergeCache.remove(pair);
2555 } else {
2556 m = new WildcardType(syms.objectType,
2557 BoundKind.UNBOUND,
2558 syms.boundClass);
2559 }
2560 merged.append(m.withTypeVar(typarams.head));
2561 }
2562 act1 = act1.tail;
2563 act2 = act2.tail;
2564 typarams = typarams.tail;
2565 }
2566 assert(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
2567 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
2568 }
2570 /**
2571 * Return the minimum type of a closure, a compound type if no
2572 * unique minimum exists.
2573 */
2574 private Type compoundMin(List<Type> cl) {
2575 if (cl.isEmpty()) return syms.objectType;
2576 List<Type> compound = closureMin(cl);
2577 if (compound.isEmpty())
2578 return null;
2579 else if (compound.tail.isEmpty())
2580 return compound.head;
2581 else
2582 return makeCompoundType(compound);
2583 }
2585 /**
2586 * Return the minimum types of a closure, suitable for computing
2587 * compoundMin or glb.
2588 */
2589 private List<Type> closureMin(List<Type> cl) {
2590 ListBuffer<Type> classes = lb();
2591 ListBuffer<Type> interfaces = lb();
2592 while (!cl.isEmpty()) {
2593 Type current = cl.head;
2594 if (current.isInterface())
2595 interfaces.append(current);
2596 else
2597 classes.append(current);
2598 ListBuffer<Type> candidates = lb();
2599 for (Type t : cl.tail) {
2600 if (!isSubtypeNoCapture(current, t))
2601 candidates.append(t);
2602 }
2603 cl = candidates.toList();
2604 }
2605 return classes.appendList(interfaces).toList();
2606 }
2608 /**
2609 * Return the least upper bound of pair of types. if the lub does
2610 * not exist return null.
2611 */
2612 public Type lub(Type t1, Type t2) {
2613 return lub(List.of(t1, t2));
2614 }
2616 /**
2617 * Return the least upper bound (lub) of set of types. If the lub
2618 * does not exist return the type of null (bottom).
2619 */
2620 public Type lub(List<Type> ts) {
2621 final int ARRAY_BOUND = 1;
2622 final int CLASS_BOUND = 2;
2623 int boundkind = 0;
2624 for (Type t : ts) {
2625 switch (t.tag) {
2626 case CLASS:
2627 boundkind |= CLASS_BOUND;
2628 break;
2629 case ARRAY:
2630 boundkind |= ARRAY_BOUND;
2631 break;
2632 case TYPEVAR:
2633 do {
2634 t = t.getUpperBound();
2635 } while (t.tag == TYPEVAR);
2636 if (t.tag == ARRAY) {
2637 boundkind |= ARRAY_BOUND;
2638 } else {
2639 boundkind |= CLASS_BOUND;
2640 }
2641 break;
2642 default:
2643 if (t.isPrimitive())
2644 return syms.errType;
2645 }
2646 }
2647 switch (boundkind) {
2648 case 0:
2649 return syms.botType;
2651 case ARRAY_BOUND:
2652 // calculate lub(A[], B[])
2653 List<Type> elements = Type.map(ts, elemTypeFun);
2654 for (Type t : elements) {
2655 if (t.isPrimitive()) {
2656 // if a primitive type is found, then return
2657 // arraySuperType unless all the types are the
2658 // same
2659 Type first = ts.head;
2660 for (Type s : ts.tail) {
2661 if (!isSameType(first, s)) {
2662 // lub(int[], B[]) is Cloneable & Serializable
2663 return arraySuperType();
2664 }
2665 }
2666 // all the array types are the same, return one
2667 // lub(int[], int[]) is int[]
2668 return first;
2669 }
2670 }
2671 // lub(A[], B[]) is lub(A, B)[]
2672 return new ArrayType(lub(elements), syms.arrayClass);
2674 case CLASS_BOUND:
2675 // calculate lub(A, B)
2676 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
2677 ts = ts.tail;
2678 assert !ts.isEmpty();
2679 List<Type> cl = closure(ts.head);
2680 for (Type t : ts.tail) {
2681 if (t.tag == CLASS || t.tag == TYPEVAR)
2682 cl = intersect(cl, closure(t));
2683 }
2684 return compoundMin(cl);
2686 default:
2687 // calculate lub(A, B[])
2688 List<Type> classes = List.of(arraySuperType());
2689 for (Type t : ts) {
2690 if (t.tag != ARRAY) // Filter out any arrays
2691 classes = classes.prepend(t);
2692 }
2693 // lub(A, B[]) is lub(A, arraySuperType)
2694 return lub(classes);
2695 }
2696 }
2697 // where
2698 private Type arraySuperType = null;
2699 private Type arraySuperType() {
2700 // initialized lazily to avoid problems during compiler startup
2701 if (arraySuperType == null) {
2702 synchronized (this) {
2703 if (arraySuperType == null) {
2704 // JLS 10.8: all arrays implement Cloneable and Serializable.
2705 arraySuperType = makeCompoundType(List.of(syms.serializableType,
2706 syms.cloneableType),
2707 syms.objectType);
2708 }
2709 }
2710 }
2711 return arraySuperType;
2712 }
2713 // </editor-fold>
2715 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
2716 public Type glb(List<Type> ts) {
2717 Type t1 = ts.head;
2718 for (Type t2 : ts.tail) {
2719 if (t1.isErroneous())
2720 return t1;
2721 t1 = glb(t1, t2);
2722 }
2723 return t1;
2724 }
2725 //where
2726 public Type glb(Type t, Type s) {
2727 if (s == null)
2728 return t;
2729 else if (isSubtypeNoCapture(t, s))
2730 return t;
2731 else if (isSubtypeNoCapture(s, t))
2732 return s;
2734 List<Type> closure = union(closure(t), closure(s));
2735 List<Type> bounds = closureMin(closure);
2737 if (bounds.isEmpty()) { // length == 0
2738 return syms.objectType;
2739 } else if (bounds.tail.isEmpty()) { // length == 1
2740 return bounds.head;
2741 } else { // length > 1
2742 int classCount = 0;
2743 for (Type bound : bounds)
2744 if (!bound.isInterface())
2745 classCount++;
2746 if (classCount > 1)
2747 return createErrorType(t);
2748 }
2749 return makeCompoundType(bounds);
2750 }
2751 // </editor-fold>
2753 // <editor-fold defaultstate="collapsed" desc="hashCode">
2754 /**
2755 * Compute a hash code on a type.
2756 */
2757 public static int hashCode(Type t) {
2758 return hashCode.visit(t);
2759 }
2760 // where
2761 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
2763 public Integer visitType(Type t, Void ignored) {
2764 return t.tag;
2765 }
2767 @Override
2768 public Integer visitClassType(ClassType t, Void ignored) {
2769 int result = visit(t.getEnclosingType());
2770 result *= 127;
2771 result += t.tsym.flatName().hashCode();
2772 for (Type s : t.getTypeArguments()) {
2773 result *= 127;
2774 result += visit(s);
2775 }
2776 return result;
2777 }
2779 @Override
2780 public Integer visitWildcardType(WildcardType t, Void ignored) {
2781 int result = t.kind.hashCode();
2782 if (t.type != null) {
2783 result *= 127;
2784 result += visit(t.type);
2785 }
2786 return result;
2787 }
2789 @Override
2790 public Integer visitArrayType(ArrayType t, Void ignored) {
2791 return visit(t.elemtype) + 12;
2792 }
2794 @Override
2795 public Integer visitTypeVar(TypeVar t, Void ignored) {
2796 return System.identityHashCode(t.tsym);
2797 }
2799 @Override
2800 public Integer visitUndetVar(UndetVar t, Void ignored) {
2801 return System.identityHashCode(t);
2802 }
2804 @Override
2805 public Integer visitErrorType(ErrorType t, Void ignored) {
2806 return 0;
2807 }
2808 };
2809 // </editor-fold>
2811 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
2812 /**
2813 * Does t have a result that is a subtype of the result type of s,
2814 * suitable for covariant returns? It is assumed that both types
2815 * are (possibly polymorphic) method types. Monomorphic method
2816 * types are handled in the obvious way. Polymorphic method types
2817 * require renaming all type variables of one to corresponding
2818 * type variables in the other, where correspondence is by
2819 * position in the type parameter list. */
2820 public boolean resultSubtype(Type t, Type s, Warner warner) {
2821 List<Type> tvars = t.getTypeArguments();
2822 List<Type> svars = s.getTypeArguments();
2823 Type tres = t.getReturnType();
2824 Type sres = subst(s.getReturnType(), svars, tvars);
2825 return covariantReturnType(tres, sres, warner);
2826 }
2828 /**
2829 * Return-Type-Substitutable.
2830 * @see <a href="http://java.sun.com/docs/books/jls/">The Java
2831 * Language Specification, Third Ed. (8.4.5)</a>
2832 */
2833 public boolean returnTypeSubstitutable(Type r1, Type r2) {
2834 if (hasSameArgs(r1, r2))
2835 return resultSubtype(r1, r2, Warner.noWarnings);
2836 else
2837 return covariantReturnType(r1.getReturnType(),
2838 erasure(r2.getReturnType()),
2839 Warner.noWarnings);
2840 }
2842 public boolean returnTypeSubstitutable(Type r1,
2843 Type r2, Type r2res,
2844 Warner warner) {
2845 if (isSameType(r1.getReturnType(), r2res))
2846 return true;
2847 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
2848 return false;
2850 if (hasSameArgs(r1, r2))
2851 return covariantReturnType(r1.getReturnType(), r2res, warner);
2852 if (!source.allowCovariantReturns())
2853 return false;
2854 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
2855 return true;
2856 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
2857 return false;
2858 warner.warnUnchecked();
2859 return true;
2860 }
2862 /**
2863 * Is t an appropriate return type in an overrider for a
2864 * method that returns s?
2865 */
2866 public boolean covariantReturnType(Type t, Type s, Warner warner) {
2867 return
2868 isSameType(t, s) ||
2869 source.allowCovariantReturns() &&
2870 !t.isPrimitive() &&
2871 !s.isPrimitive() &&
2872 isAssignable(t, s, warner);
2873 }
2874 // </editor-fold>
2876 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
2877 /**
2878 * Return the class that boxes the given primitive.
2879 */
2880 public ClassSymbol boxedClass(Type t) {
2881 return reader.enterClass(syms.boxedName[t.tag]);
2882 }
2884 /**
2885 * Return the primitive type corresponding to a boxed type.
2886 */
2887 public Type unboxedType(Type t) {
2888 if (allowBoxing) {
2889 for (int i=0; i<syms.boxedName.length; i++) {
2890 Name box = syms.boxedName[i];
2891 if (box != null &&
2892 asSuper(t, reader.enterClass(box)) != null)
2893 return syms.typeOfTag[i];
2894 }
2895 }
2896 return Type.noType;
2897 }
2898 // </editor-fold>
2900 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
2901 /*
2902 * JLS 3rd Ed. 5.1.10 Capture Conversion:
2903 *
2904 * Let G name a generic type declaration with n formal type
2905 * parameters A1 ... An with corresponding bounds U1 ... Un. There
2906 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
2907 * where, for 1 <= i <= n:
2908 *
2909 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
2910 * Si is a fresh type variable whose upper bound is
2911 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
2912 * type.
2913 *
2914 * + If Ti is a wildcard type argument of the form ? extends Bi,
2915 * then Si is a fresh type variable whose upper bound is
2916 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
2917 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
2918 * a compile-time error if for any two classes (not interfaces)
2919 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
2920 *
2921 * + If Ti is a wildcard type argument of the form ? super Bi,
2922 * then Si is a fresh type variable whose upper bound is
2923 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
2924 *
2925 * + Otherwise, Si = Ti.
2926 *
2927 * Capture conversion on any type other than a parameterized type
2928 * (4.5) acts as an identity conversion (5.1.1). Capture
2929 * conversions never require a special action at run time and
2930 * therefore never throw an exception at run time.
2931 *
2932 * Capture conversion is not applied recursively.
2933 */
2934 /**
2935 * Capture conversion as specified by JLS 3rd Ed.
2936 */
2938 public List<Type> capture(List<Type> ts) {
2939 List<Type> buf = List.nil();
2940 for (Type t : ts) {
2941 buf = buf.prepend(capture(t));
2942 }
2943 return buf.reverse();
2944 }
2945 public Type capture(Type t) {
2946 if (t.tag != CLASS)
2947 return t;
2948 ClassType cls = (ClassType)t;
2949 if (cls.isRaw() || !cls.isParameterized())
2950 return cls;
2952 ClassType G = (ClassType)cls.asElement().asType();
2953 List<Type> A = G.getTypeArguments();
2954 List<Type> T = cls.getTypeArguments();
2955 List<Type> S = freshTypeVariables(T);
2957 List<Type> currentA = A;
2958 List<Type> currentT = T;
2959 List<Type> currentS = S;
2960 boolean captured = false;
2961 while (!currentA.isEmpty() &&
2962 !currentT.isEmpty() &&
2963 !currentS.isEmpty()) {
2964 if (currentS.head != currentT.head) {
2965 captured = true;
2966 WildcardType Ti = (WildcardType)currentT.head;
2967 Type Ui = currentA.head.getUpperBound();
2968 CapturedType Si = (CapturedType)currentS.head;
2969 if (Ui == null)
2970 Ui = syms.objectType;
2971 switch (Ti.kind) {
2972 case UNBOUND:
2973 Si.bound = subst(Ui, A, S);
2974 Si.lower = syms.botType;
2975 break;
2976 case EXTENDS:
2977 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
2978 Si.lower = syms.botType;
2979 break;
2980 case SUPER:
2981 Si.bound = subst(Ui, A, S);
2982 Si.lower = Ti.getSuperBound();
2983 break;
2984 }
2985 if (Si.bound == Si.lower)
2986 currentS.head = Si.bound;
2987 }
2988 currentA = currentA.tail;
2989 currentT = currentT.tail;
2990 currentS = currentS.tail;
2991 }
2992 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
2993 return erasure(t); // some "rare" type involved
2995 if (captured)
2996 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
2997 else
2998 return t;
2999 }
3000 // where
3001 public List<Type> freshTypeVariables(List<Type> types) {
3002 ListBuffer<Type> result = lb();
3003 for (Type t : types) {
3004 if (t.tag == WILDCARD) {
3005 Type bound = ((WildcardType)t).getExtendsBound();
3006 if (bound == null)
3007 bound = syms.objectType;
3008 result.append(new CapturedType(capturedName,
3009 syms.noSymbol,
3010 bound,
3011 syms.botType,
3012 (WildcardType)t));
3013 } else {
3014 result.append(t);
3015 }
3016 }
3017 return result.toList();
3018 }
3019 // </editor-fold>
3021 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3022 private List<Type> upperBounds(List<Type> ss) {
3023 if (ss.isEmpty()) return ss;
3024 Type head = upperBound(ss.head);
3025 List<Type> tail = upperBounds(ss.tail);
3026 if (head != ss.head || tail != ss.tail)
3027 return tail.prepend(head);
3028 else
3029 return ss;
3030 }
3032 private boolean sideCast(Type from, Type to, Warner warn) {
3033 // We are casting from type $from$ to type $to$, which are
3034 // non-final unrelated types. This method
3035 // tries to reject a cast by transferring type parameters
3036 // from $to$ to $from$ by common superinterfaces.
3037 boolean reverse = false;
3038 Type target = to;
3039 if ((to.tsym.flags() & INTERFACE) == 0) {
3040 assert (from.tsym.flags() & INTERFACE) != 0;
3041 reverse = true;
3042 to = from;
3043 from = target;
3044 }
3045 List<Type> commonSupers = superClosure(to, erasure(from));
3046 boolean giveWarning = commonSupers.isEmpty();
3047 // The arguments to the supers could be unified here to
3048 // get a more accurate analysis
3049 while (commonSupers.nonEmpty()) {
3050 Type t1 = asSuper(from, commonSupers.head.tsym);
3051 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3052 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3053 return false;
3054 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3055 commonSupers = commonSupers.tail;
3056 }
3057 if (giveWarning && !isReifiable(reverse ? from : to))
3058 warn.warnUnchecked();
3059 if (!source.allowCovariantReturns())
3060 // reject if there is a common method signature with
3061 // incompatible return types.
3062 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3063 return true;
3064 }
3066 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3067 // We are casting from type $from$ to type $to$, which are
3068 // unrelated types one of which is final and the other of
3069 // which is an interface. This method
3070 // tries to reject a cast by transferring type parameters
3071 // from the final class to the interface.
3072 boolean reverse = false;
3073 Type target = to;
3074 if ((to.tsym.flags() & INTERFACE) == 0) {
3075 assert (from.tsym.flags() & INTERFACE) != 0;
3076 reverse = true;
3077 to = from;
3078 from = target;
3079 }
3080 assert (from.tsym.flags() & FINAL) != 0;
3081 Type t1 = asSuper(from, to.tsym);
3082 if (t1 == null) return false;
3083 Type t2 = to;
3084 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3085 return false;
3086 if (!source.allowCovariantReturns())
3087 // reject if there is a common method signature with
3088 // incompatible return types.
3089 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3090 if (!isReifiable(target) &&
3091 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3092 warn.warnUnchecked();
3093 return true;
3094 }
3096 private boolean giveWarning(Type from, Type to) {
3097 Type subFrom = asSub(from, to.tsym);
3098 return to.isParameterized() &&
3099 (!(isUnbounded(to) ||
3100 isSubtype(from, to) ||
3101 ((subFrom != null) && isSameType(subFrom, to))));
3102 }
3104 private List<Type> superClosure(Type t, Type s) {
3105 List<Type> cl = List.nil();
3106 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3107 if (isSubtype(s, erasure(l.head))) {
3108 cl = insert(cl, l.head);
3109 } else {
3110 cl = union(cl, superClosure(l.head, s));
3111 }
3112 }
3113 return cl;
3114 }
3116 private boolean containsTypeEquivalent(Type t, Type s) {
3117 return
3118 isSameType(t, s) || // shortcut
3119 containsType(t, s) && containsType(s, t);
3120 }
3122 // <editor-fold defaultstate="collapsed" desc="adapt">
3123 /**
3124 * Adapt a type by computing a substitution which maps a source
3125 * type to a target type.
3126 *
3127 * @param source the source type
3128 * @param target the target type
3129 * @param from the type variables of the computed substitution
3130 * @param to the types of the computed substitution.
3131 */
3132 public void adapt(Type source,
3133 Type target,
3134 ListBuffer<Type> from,
3135 ListBuffer<Type> to) throws AdaptFailure {
3136 new Adapter(from, to).adapt(source, target);
3137 }
3139 class Adapter extends SimpleVisitor<Void, Type> {
3141 ListBuffer<Type> from;
3142 ListBuffer<Type> to;
3143 Map<Symbol,Type> mapping;
3145 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3146 this.from = from;
3147 this.to = to;
3148 mapping = new HashMap<Symbol,Type>();
3149 }
3151 public void adapt(Type source, Type target) throws AdaptFailure {
3152 visit(source, target);
3153 List<Type> fromList = from.toList();
3154 List<Type> toList = to.toList();
3155 while (!fromList.isEmpty()) {
3156 Type val = mapping.get(fromList.head.tsym);
3157 if (toList.head != val)
3158 toList.head = val;
3159 fromList = fromList.tail;
3160 toList = toList.tail;
3161 }
3162 }
3164 @Override
3165 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3166 if (target.tag == CLASS)
3167 adaptRecursive(source.allparams(), target.allparams());
3168 return null;
3169 }
3171 @Override
3172 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3173 if (target.tag == ARRAY)
3174 adaptRecursive(elemtype(source), elemtype(target));
3175 return null;
3176 }
3178 @Override
3179 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3180 if (source.isExtendsBound())
3181 adaptRecursive(upperBound(source), upperBound(target));
3182 else if (source.isSuperBound())
3183 adaptRecursive(lowerBound(source), lowerBound(target));
3184 return null;
3185 }
3187 @Override
3188 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3189 // Check to see if there is
3190 // already a mapping for $source$, in which case
3191 // the old mapping will be merged with the new
3192 Type val = mapping.get(source.tsym);
3193 if (val != null) {
3194 if (val.isSuperBound() && target.isSuperBound()) {
3195 val = isSubtype(lowerBound(val), lowerBound(target))
3196 ? target : val;
3197 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3198 val = isSubtype(upperBound(val), upperBound(target))
3199 ? val : target;
3200 } else if (!isSameType(val, target)) {
3201 throw new AdaptFailure();
3202 }
3203 } else {
3204 val = target;
3205 from.append(source);
3206 to.append(target);
3207 }
3208 mapping.put(source.tsym, val);
3209 return null;
3210 }
3212 @Override
3213 public Void visitType(Type source, Type target) {
3214 return null;
3215 }
3217 private Set<TypePair> cache = new HashSet<TypePair>();
3219 private void adaptRecursive(Type source, Type target) {
3220 TypePair pair = new TypePair(source, target);
3221 if (cache.add(pair)) {
3222 try {
3223 visit(source, target);
3224 } finally {
3225 cache.remove(pair);
3226 }
3227 }
3228 }
3230 private void adaptRecursive(List<Type> source, List<Type> target) {
3231 if (source.length() == target.length()) {
3232 while (source.nonEmpty()) {
3233 adaptRecursive(source.head, target.head);
3234 source = source.tail;
3235 target = target.tail;
3236 }
3237 }
3238 }
3239 }
3241 public static class AdaptFailure extends RuntimeException {
3242 static final long serialVersionUID = -7490231548272701566L;
3243 }
3245 private void adaptSelf(Type t,
3246 ListBuffer<Type> from,
3247 ListBuffer<Type> to) {
3248 try {
3249 //if (t.tsym.type != t)
3250 adapt(t.tsym.type, t, from, to);
3251 } catch (AdaptFailure ex) {
3252 // Adapt should never fail calculating a mapping from
3253 // t.tsym.type to t as there can be no merge problem.
3254 throw new AssertionError(ex);
3255 }
3256 }
3257 // </editor-fold>
3259 /**
3260 * Rewrite all type variables (universal quantifiers) in the given
3261 * type to wildcards (existential quantifiers). This is used to
3262 * determine if a cast is allowed. For example, if high is true
3263 * and {@code T <: Number}, then {@code List<T>} is rewritten to
3264 * {@code List<? extends Number>}. Since {@code List<Integer> <:
3265 * List<? extends Number>} a {@code List<T>} can be cast to {@code
3266 * List<Integer>} with a warning.
3267 * @param t a type
3268 * @param high if true return an upper bound; otherwise a lower
3269 * bound
3270 * @param rewriteTypeVars only rewrite captured wildcards if false;
3271 * otherwise rewrite all type variables
3272 * @return the type rewritten with wildcards (existential
3273 * quantifiers) only
3274 */
3275 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
3276 return new Rewriter(high, rewriteTypeVars).rewrite(t);
3277 }
3279 class Rewriter extends UnaryVisitor<Type> {
3281 boolean high;
3282 boolean rewriteTypeVars;
3284 Rewriter(boolean high, boolean rewriteTypeVars) {
3285 this.high = high;
3286 this.rewriteTypeVars = rewriteTypeVars;
3287 }
3289 Type rewrite(Type t) {
3290 ListBuffer<Type> from = new ListBuffer<Type>();
3291 ListBuffer<Type> to = new ListBuffer<Type>();
3292 adaptSelf(t, from, to);
3293 ListBuffer<Type> rewritten = new ListBuffer<Type>();
3294 List<Type> formals = from.toList();
3295 boolean changed = false;
3296 for (Type arg : to.toList()) {
3297 Type bound = visit(arg);
3298 if (arg != bound) {
3299 changed = true;
3300 bound = high ? makeExtendsWildcard(bound, (TypeVar)formals.head)
3301 : makeSuperWildcard(bound, (TypeVar)formals.head);
3302 }
3303 rewritten.append(bound);
3304 formals = formals.tail;
3305 }
3306 if (changed)
3307 return subst(t.tsym.type, from.toList(), rewritten.toList());
3308 else
3309 return t;
3310 }
3312 public Type visitType(Type t, Void s) {
3313 return high ? upperBound(t) : lowerBound(t);
3314 }
3316 @Override
3317 public Type visitCapturedType(CapturedType t, Void s) {
3318 return visitWildcardType(t.wildcard, null);
3319 }
3321 @Override
3322 public Type visitTypeVar(TypeVar t, Void s) {
3323 if (rewriteTypeVars)
3324 return high ? t.bound : syms.botType;
3325 else
3326 return t;
3327 }
3329 @Override
3330 public Type visitWildcardType(WildcardType t, Void s) {
3331 Type bound = high ? t.getExtendsBound() :
3332 t.getSuperBound();
3333 if (bound == null)
3334 bound = high ? syms.objectType : syms.botType;
3335 return bound;
3336 }
3337 }
3339 /**
3340 * Create a wildcard with the given upper (extends) bound; create
3341 * an unbounded wildcard if bound is Object.
3342 *
3343 * @param bound the upper bound
3344 * @param formal the formal type parameter that will be
3345 * substituted by the wildcard
3346 */
3347 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
3348 if (bound == syms.objectType) {
3349 return new WildcardType(syms.objectType,
3350 BoundKind.UNBOUND,
3351 syms.boundClass,
3352 formal);
3353 } else {
3354 return new WildcardType(bound,
3355 BoundKind.EXTENDS,
3356 syms.boundClass,
3357 formal);
3358 }
3359 }
3361 /**
3362 * Create a wildcard with the given lower (super) bound; create an
3363 * unbounded wildcard if bound is bottom (type of {@code null}).
3364 *
3365 * @param bound the lower bound
3366 * @param formal the formal type parameter that will be
3367 * substituted by the wildcard
3368 */
3369 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
3370 if (bound.tag == BOT) {
3371 return new WildcardType(syms.objectType,
3372 BoundKind.UNBOUND,
3373 syms.boundClass,
3374 formal);
3375 } else {
3376 return new WildcardType(bound,
3377 BoundKind.SUPER,
3378 syms.boundClass,
3379 formal);
3380 }
3381 }
3383 /**
3384 * A wrapper for a type that allows use in sets.
3385 */
3386 class SingletonType {
3387 final Type t;
3388 SingletonType(Type t) {
3389 this.t = t;
3390 }
3391 public int hashCode() {
3392 return Types.hashCode(t);
3393 }
3394 public boolean equals(Object obj) {
3395 return (obj instanceof SingletonType) &&
3396 isSameType(t, ((SingletonType)obj).t);
3397 }
3398 public String toString() {
3399 return t.toString();
3400 }
3401 }
3402 // </editor-fold>
3404 // <editor-fold defaultstate="collapsed" desc="Visitors">
3405 /**
3406 * A default visitor for types. All visitor methods except
3407 * visitType are implemented by delegating to visitType. Concrete
3408 * subclasses must provide an implementation of visitType and can
3409 * override other methods as needed.
3410 *
3411 * @param <R> the return type of the operation implemented by this
3412 * visitor; use Void if no return type is needed.
3413 * @param <S> the type of the second argument (the first being the
3414 * type itself) of the operation implemented by this visitor; use
3415 * Void if a second argument is not needed.
3416 */
3417 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
3418 final public R visit(Type t, S s) { return t.accept(this, s); }
3419 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
3420 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
3421 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
3422 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
3423 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
3424 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
3425 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
3426 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
3427 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
3428 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
3429 }
3431 /**
3432 * A default visitor for symbols. All visitor methods except
3433 * visitSymbol are implemented by delegating to visitSymbol. Concrete
3434 * subclasses must provide an implementation of visitSymbol and can
3435 * override other methods as needed.
3436 *
3437 * @param <R> the return type of the operation implemented by this
3438 * visitor; use Void if no return type is needed.
3439 * @param <S> the type of the second argument (the first being the
3440 * symbol itself) of the operation implemented by this visitor; use
3441 * Void if a second argument is not needed.
3442 */
3443 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
3444 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
3445 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
3446 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
3447 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
3448 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
3449 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
3450 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
3451 }
3453 /**
3454 * A <em>simple</em> visitor for types. This visitor is simple as
3455 * captured wildcards, for-all types (generic methods), and
3456 * undetermined type variables (part of inference) are hidden.
3457 * Captured wildcards are hidden by treating them as type
3458 * variables and the rest are hidden by visiting their qtypes.
3459 *
3460 * @param <R> the return type of the operation implemented by this
3461 * visitor; use Void if no return type is needed.
3462 * @param <S> the type of the second argument (the first being the
3463 * type itself) of the operation implemented by this visitor; use
3464 * Void if a second argument is not needed.
3465 */
3466 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
3467 @Override
3468 public R visitCapturedType(CapturedType t, S s) {
3469 return visitTypeVar(t, s);
3470 }
3471 @Override
3472 public R visitForAll(ForAll t, S s) {
3473 return visit(t.qtype, s);
3474 }
3475 @Override
3476 public R visitUndetVar(UndetVar t, S s) {
3477 return visit(t.qtype, s);
3478 }
3479 }
3481 /**
3482 * A plain relation on types. That is a 2-ary function on the
3483 * form Type × Type → Boolean.
3484 * <!-- In plain text: Type x Type -> Boolean -->
3485 */
3486 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
3488 /**
3489 * A convenience visitor for implementing operations that only
3490 * require one argument (the type itself), that is, unary
3491 * operations.
3492 *
3493 * @param <R> the return type of the operation implemented by this
3494 * visitor; use Void if no return type is needed.
3495 */
3496 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
3497 final public R visit(Type t) { return t.accept(this, null); }
3498 }
3500 /**
3501 * A visitor for implementing a mapping from types to types. The
3502 * default behavior of this class is to implement the identity
3503 * mapping (mapping a type to itself). This can be overridden in
3504 * subclasses.
3505 *
3506 * @param <S> the type of the second argument (the first being the
3507 * type itself) of this mapping; use Void if a second argument is
3508 * not needed.
3509 */
3510 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
3511 final public Type visit(Type t) { return t.accept(this, null); }
3512 public Type visitType(Type t, S s) { return t; }
3513 }
3514 // </editor-fold>
3515 }
