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src/share/classes/com/sun/tools/javac/code/Types.java@85fecace920b
src/share/classes/com/sun/tools/javac/code/Types.java
Thu, 30 Jul 2009 10:29:53 +0100
- author
- mcimadamore
- date
- Thu, 30 Jul 2009 10:29:53 +0100
- changeset 341
- 85fecace920b
- parent 299
- 22872b24d38c
- child 356
- d5f6c475f475
- permissions
- -rw-r--r--
6827648: Extremely slow compilation time for visitor pattern code + generics
Summary: Javac unnecessarily recomputates type-substitutions multiple times
Reviewed-by: jjg
1 /*
2 * Copyright 2003-2009 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any 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 API supported by Sun Microsystems.
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 return s.isSuperBound()
593 && !s.isExtendsBound()
594 && visit(t, upperBound(s));
595 default:
596 throw new AssertionError("isSameType " + t.tag);
597 }
598 }
600 @Override
601 public Boolean visitWildcardType(WildcardType t, Type s) {
602 if (s.tag >= firstPartialTag)
603 return visit(s, t);
604 else
605 return false;
606 }
608 @Override
609 public Boolean visitClassType(ClassType t, Type s) {
610 if (t == s)
611 return true;
613 if (s.tag >= firstPartialTag)
614 return visit(s, t);
616 if (s.isSuperBound() && !s.isExtendsBound())
617 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
619 if (t.isCompound() && s.isCompound()) {
620 if (!visit(supertype(t), supertype(s)))
621 return false;
623 HashSet<SingletonType> set = new HashSet<SingletonType>();
624 for (Type x : interfaces(t))
625 set.add(new SingletonType(x));
626 for (Type x : interfaces(s)) {
627 if (!set.remove(new SingletonType(x)))
628 return false;
629 }
630 return (set.size() == 0);
631 }
632 return t.tsym == s.tsym
633 && visit(t.getEnclosingType(), s.getEnclosingType())
634 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
635 }
637 @Override
638 public Boolean visitArrayType(ArrayType t, Type s) {
639 if (t == s)
640 return true;
642 if (s.tag >= firstPartialTag)
643 return visit(s, t);
645 return s.tag == ARRAY
646 && containsTypeEquivalent(t.elemtype, elemtype(s));
647 }
649 @Override
650 public Boolean visitMethodType(MethodType t, Type s) {
651 // isSameType for methods does not take thrown
652 // exceptions into account!
653 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
654 }
656 @Override
657 public Boolean visitPackageType(PackageType t, Type s) {
658 return t == s;
659 }
661 @Override
662 public Boolean visitForAll(ForAll t, Type s) {
663 if (s.tag != FORALL)
664 return false;
666 ForAll forAll = (ForAll)s;
667 return hasSameBounds(t, forAll)
668 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
669 }
671 @Override
672 public Boolean visitUndetVar(UndetVar t, Type s) {
673 if (s.tag == WILDCARD)
674 // FIXME, this might be leftovers from before capture conversion
675 return false;
677 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
678 return true;
680 if (t.inst != null)
681 return visit(t.inst, s);
683 t.inst = fromUnknownFun.apply(s);
684 for (List<Type> l = t.lobounds; l.nonEmpty(); l = l.tail) {
685 if (!isSubtype(l.head, t.inst))
686 return false;
687 }
688 for (List<Type> l = t.hibounds; l.nonEmpty(); l = l.tail) {
689 if (!isSubtype(t.inst, l.head))
690 return false;
691 }
692 return true;
693 }
695 @Override
696 public Boolean visitErrorType(ErrorType t, Type s) {
697 return true;
698 }
699 };
700 // </editor-fold>
702 // <editor-fold defaultstate="collapsed" desc="fromUnknownFun">
703 /**
704 * A mapping that turns all unknown types in this type to fresh
705 * unknown variables.
706 */
707 public Mapping fromUnknownFun = new Mapping("fromUnknownFun") {
708 public Type apply(Type t) {
709 if (t.tag == UNKNOWN) return new UndetVar(t);
710 else return t.map(this);
711 }
712 };
713 // </editor-fold>
715 // <editor-fold defaultstate="collapsed" desc="Contains Type">
716 public boolean containedBy(Type t, Type s) {
717 switch (t.tag) {
718 case UNDETVAR:
719 if (s.tag == WILDCARD) {
720 UndetVar undetvar = (UndetVar)t;
721 WildcardType wt = (WildcardType)s;
722 switch(wt.kind) {
723 case UNBOUND: //similar to ? extends Object
724 case EXTENDS: {
725 Type bound = upperBound(s);
726 // We should check the new upper bound against any of the
727 // undetvar's lower bounds.
728 for (Type t2 : undetvar.lobounds) {
729 if (!isSubtype(t2, bound))
730 return false;
731 }
732 undetvar.hibounds = undetvar.hibounds.prepend(bound);
733 break;
734 }
735 case SUPER: {
736 Type bound = lowerBound(s);
737 // We should check the new lower bound against any of the
738 // undetvar's lower bounds.
739 for (Type t2 : undetvar.hibounds) {
740 if (!isSubtype(bound, t2))
741 return false;
742 }
743 undetvar.lobounds = undetvar.lobounds.prepend(bound);
744 break;
745 }
746 }
747 return true;
748 } else {
749 return isSameType(t, s);
750 }
751 case ERROR:
752 return true;
753 default:
754 return containsType(s, t);
755 }
756 }
758 boolean containsType(List<Type> ts, List<Type> ss) {
759 while (ts.nonEmpty() && ss.nonEmpty()
760 && containsType(ts.head, ss.head)) {
761 ts = ts.tail;
762 ss = ss.tail;
763 }
764 return ts.isEmpty() && ss.isEmpty();
765 }
767 /**
768 * Check if t contains s.
769 *
770 * <p>T contains S if:
771 *
772 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
773 *
774 * <p>This relation is only used by ClassType.isSubtype(), that
775 * is,
776 *
777 * <p>{@code C<S> <: C<T> if T contains S.}
778 *
779 * <p>Because of F-bounds, this relation can lead to infinite
780 * recursion. Thus we must somehow break that recursion. Notice
781 * that containsType() is only called from ClassType.isSubtype().
782 * Since the arguments have already been checked against their
783 * bounds, we know:
784 *
785 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
786 *
787 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
788 *
789 * @param t a type
790 * @param s a type
791 */
792 public boolean containsType(Type t, Type s) {
793 return containsType.visit(t, s);
794 }
795 // where
796 private TypeRelation containsType = new TypeRelation() {
798 private Type U(Type t) {
799 while (t.tag == WILDCARD) {
800 WildcardType w = (WildcardType)t;
801 if (w.isSuperBound())
802 return w.bound == null ? syms.objectType : w.bound.bound;
803 else
804 t = w.type;
805 }
806 return t;
807 }
809 private Type L(Type t) {
810 while (t.tag == WILDCARD) {
811 WildcardType w = (WildcardType)t;
812 if (w.isExtendsBound())
813 return syms.botType;
814 else
815 t = w.type;
816 }
817 return t;
818 }
820 public Boolean visitType(Type t, Type s) {
821 if (s.tag >= firstPartialTag)
822 return containedBy(s, t);
823 else
824 return isSameType(t, s);
825 }
827 void debugContainsType(WildcardType t, Type s) {
828 System.err.println();
829 System.err.format(" does %s contain %s?%n", t, s);
830 System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
831 upperBound(s), s, t, U(t),
832 t.isSuperBound()
833 || isSubtypeNoCapture(upperBound(s), U(t)));
834 System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
835 L(t), t, s, lowerBound(s),
836 t.isExtendsBound()
837 || isSubtypeNoCapture(L(t), lowerBound(s)));
838 System.err.println();
839 }
841 @Override
842 public Boolean visitWildcardType(WildcardType t, Type s) {
843 if (s.tag >= firstPartialTag)
844 return containedBy(s, t);
845 else {
846 // debugContainsType(t, s);
847 return isSameWildcard(t, s)
848 || isCaptureOf(s, t)
849 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
850 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
851 }
852 }
854 @Override
855 public Boolean visitUndetVar(UndetVar t, Type s) {
856 if (s.tag != WILDCARD)
857 return isSameType(t, s);
858 else
859 return false;
860 }
862 @Override
863 public Boolean visitErrorType(ErrorType t, Type s) {
864 return true;
865 }
866 };
868 public boolean isCaptureOf(Type s, WildcardType t) {
869 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
870 return false;
871 return isSameWildcard(t, ((CapturedType)s).wildcard);
872 }
874 public boolean isSameWildcard(WildcardType t, Type s) {
875 if (s.tag != WILDCARD)
876 return false;
877 WildcardType w = (WildcardType)s;
878 return w.kind == t.kind && w.type == t.type;
879 }
881 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
882 while (ts.nonEmpty() && ss.nonEmpty()
883 && containsTypeEquivalent(ts.head, ss.head)) {
884 ts = ts.tail;
885 ss = ss.tail;
886 }
887 return ts.isEmpty() && ss.isEmpty();
888 }
889 // </editor-fold>
891 // <editor-fold defaultstate="collapsed" desc="isCastable">
892 public boolean isCastable(Type t, Type s) {
893 return isCastable(t, s, Warner.noWarnings);
894 }
896 /**
897 * Is t is castable to s?<br>
898 * s is assumed to be an erased type.<br>
899 * (not defined for Method and ForAll types).
900 */
901 public boolean isCastable(Type t, Type s, Warner warn) {
902 if (t == s)
903 return true;
905 if (t.isPrimitive() != s.isPrimitive())
906 return allowBoxing && isConvertible(t, s, warn);
908 if (warn != warnStack.head) {
909 try {
910 warnStack = warnStack.prepend(warn);
911 return isCastable.visit(t,s);
912 } finally {
913 warnStack = warnStack.tail;
914 }
915 } else {
916 return isCastable.visit(t,s);
917 }
918 }
919 // where
920 private TypeRelation isCastable = new TypeRelation() {
922 public Boolean visitType(Type t, Type s) {
923 if (s.tag == ERROR)
924 return true;
926 switch (t.tag) {
927 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
928 case DOUBLE:
929 return s.tag <= DOUBLE;
930 case BOOLEAN:
931 return s.tag == BOOLEAN;
932 case VOID:
933 return false;
934 case BOT:
935 return isSubtype(t, s);
936 default:
937 throw new AssertionError();
938 }
939 }
941 @Override
942 public Boolean visitWildcardType(WildcardType t, Type s) {
943 return isCastable(upperBound(t), s, warnStack.head);
944 }
946 @Override
947 public Boolean visitClassType(ClassType t, Type s) {
948 if (s.tag == ERROR || s.tag == BOT)
949 return true;
951 if (s.tag == TYPEVAR) {
952 if (isCastable(s.getUpperBound(), t, Warner.noWarnings)) {
953 warnStack.head.warnUnchecked();
954 return true;
955 } else {
956 return false;
957 }
958 }
960 if (t.isCompound()) {
961 Warner oldWarner = warnStack.head;
962 warnStack.head = Warner.noWarnings;
963 if (!visit(supertype(t), s))
964 return false;
965 for (Type intf : interfaces(t)) {
966 if (!visit(intf, s))
967 return false;
968 }
969 if (warnStack.head.unchecked == true)
970 oldWarner.warnUnchecked();
971 return true;
972 }
974 if (s.isCompound()) {
975 // call recursively to reuse the above code
976 return visitClassType((ClassType)s, t);
977 }
979 if (s.tag == CLASS || s.tag == ARRAY) {
980 boolean upcast;
981 if ((upcast = isSubtype(erasure(t), erasure(s)))
982 || isSubtype(erasure(s), erasure(t))) {
983 if (!upcast && s.tag == ARRAY) {
984 if (!isReifiable(s))
985 warnStack.head.warnUnchecked();
986 return true;
987 } else if (s.isRaw()) {
988 return true;
989 } else if (t.isRaw()) {
990 if (!isUnbounded(s))
991 warnStack.head.warnUnchecked();
992 return true;
993 }
994 // Assume |a| <: |b|
995 final Type a = upcast ? t : s;
996 final Type b = upcast ? s : t;
997 final boolean HIGH = true;
998 final boolean LOW = false;
999 final boolean DONT_REWRITE_TYPEVARS = false;
1000 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1001 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1002 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1003 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1004 Type lowSub = asSub(bLow, aLow.tsym);
1005 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1006 if (highSub == null) {
1007 final boolean REWRITE_TYPEVARS = true;
1008 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1009 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1010 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1011 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1012 lowSub = asSub(bLow, aLow.tsym);
1013 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1014 }
1015 if (highSub != null) {
1016 assert a.tsym == highSub.tsym && a.tsym == lowSub.tsym
1017 : a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym;
1018 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1019 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1020 && !disjointTypes(aLow.allparams(), highSub.allparams())
1021 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1022 if (upcast ? giveWarning(a, b) :
1023 giveWarning(b, a))
1024 warnStack.head.warnUnchecked();
1025 return true;
1026 }
1027 }
1028 if (isReifiable(s))
1029 return isSubtypeUnchecked(a, b);
1030 else
1031 return isSubtypeUnchecked(a, b, warnStack.head);
1032 }
1034 // Sidecast
1035 if (s.tag == CLASS) {
1036 if ((s.tsym.flags() & INTERFACE) != 0) {
1037 return ((t.tsym.flags() & FINAL) == 0)
1038 ? sideCast(t, s, warnStack.head)
1039 : sideCastFinal(t, s, warnStack.head);
1040 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1041 return ((s.tsym.flags() & FINAL) == 0)
1042 ? sideCast(t, s, warnStack.head)
1043 : sideCastFinal(t, s, warnStack.head);
1044 } else {
1045 // unrelated class types
1046 return false;
1047 }
1048 }
1049 }
1050 return false;
1051 }
1053 @Override
1054 public Boolean visitArrayType(ArrayType t, Type s) {
1055 switch (s.tag) {
1056 case ERROR:
1057 case BOT:
1058 return true;
1059 case TYPEVAR:
1060 if (isCastable(s, t, Warner.noWarnings)) {
1061 warnStack.head.warnUnchecked();
1062 return true;
1063 } else {
1064 return false;
1065 }
1066 case CLASS:
1067 return isSubtype(t, s);
1068 case ARRAY:
1069 if (elemtype(t).tag <= lastBaseTag) {
1070 return elemtype(t).tag == elemtype(s).tag;
1071 } else {
1072 return visit(elemtype(t), elemtype(s));
1073 }
1074 default:
1075 return false;
1076 }
1077 }
1079 @Override
1080 public Boolean visitTypeVar(TypeVar t, Type s) {
1081 switch (s.tag) {
1082 case ERROR:
1083 case BOT:
1084 return true;
1085 case TYPEVAR:
1086 if (isSubtype(t, s)) {
1087 return true;
1088 } else if (isCastable(t.bound, s, Warner.noWarnings)) {
1089 warnStack.head.warnUnchecked();
1090 return true;
1091 } else {
1092 return false;
1093 }
1094 default:
1095 return isCastable(t.bound, s, warnStack.head);
1096 }
1097 }
1099 @Override
1100 public Boolean visitErrorType(ErrorType t, Type s) {
1101 return true;
1102 }
1103 };
1104 // </editor-fold>
1106 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1107 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1108 while (ts.tail != null && ss.tail != null) {
1109 if (disjointType(ts.head, ss.head)) return true;
1110 ts = ts.tail;
1111 ss = ss.tail;
1112 }
1113 return false;
1114 }
1116 /**
1117 * Two types or wildcards are considered disjoint if it can be
1118 * proven that no type can be contained in both. It is
1119 * conservative in that it is allowed to say that two types are
1120 * not disjoint, even though they actually are.
1121 *
1122 * The type C<X> is castable to C<Y> exactly if X and Y are not
1123 * disjoint.
1124 */
1125 public boolean disjointType(Type t, Type s) {
1126 return disjointType.visit(t, s);
1127 }
1128 // where
1129 private TypeRelation disjointType = new TypeRelation() {
1131 private Set<TypePair> cache = new HashSet<TypePair>();
1133 public Boolean visitType(Type t, Type s) {
1134 if (s.tag == WILDCARD)
1135 return visit(s, t);
1136 else
1137 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1138 }
1140 private boolean isCastableRecursive(Type t, Type s) {
1141 TypePair pair = new TypePair(t, s);
1142 if (cache.add(pair)) {
1143 try {
1144 return Types.this.isCastable(t, s);
1145 } finally {
1146 cache.remove(pair);
1147 }
1148 } else {
1149 return true;
1150 }
1151 }
1153 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1154 TypePair pair = new TypePair(t, s);
1155 if (cache.add(pair)) {
1156 try {
1157 return Types.this.notSoftSubtype(t, s);
1158 } finally {
1159 cache.remove(pair);
1160 }
1161 } else {
1162 return false;
1163 }
1164 }
1166 @Override
1167 public Boolean visitWildcardType(WildcardType t, Type s) {
1168 if (t.isUnbound())
1169 return false;
1171 if (s.tag != WILDCARD) {
1172 if (t.isExtendsBound())
1173 return notSoftSubtypeRecursive(s, t.type);
1174 else // isSuperBound()
1175 return notSoftSubtypeRecursive(t.type, s);
1176 }
1178 if (s.isUnbound())
1179 return false;
1181 if (t.isExtendsBound()) {
1182 if (s.isExtendsBound())
1183 return !isCastableRecursive(t.type, upperBound(s));
1184 else if (s.isSuperBound())
1185 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1186 } else if (t.isSuperBound()) {
1187 if (s.isExtendsBound())
1188 return notSoftSubtypeRecursive(t.type, upperBound(s));
1189 }
1190 return false;
1191 }
1192 };
1193 // </editor-fold>
1195 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1196 /**
1197 * Returns the lower bounds of the formals of a method.
1198 */
1199 public List<Type> lowerBoundArgtypes(Type t) {
1200 return map(t.getParameterTypes(), lowerBoundMapping);
1201 }
1202 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1203 public Type apply(Type t) {
1204 return lowerBound(t);
1205 }
1206 };
1207 // </editor-fold>
1209 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1210 /**
1211 * This relation answers the question: is impossible that
1212 * something of type `t' can be a subtype of `s'? This is
1213 * different from the question "is `t' not a subtype of `s'?"
1214 * when type variables are involved: Integer is not a subtype of T
1215 * where <T extends Number> but it is not true that Integer cannot
1216 * possibly be a subtype of T.
1217 */
1218 public boolean notSoftSubtype(Type t, Type s) {
1219 if (t == s) return false;
1220 if (t.tag == TYPEVAR) {
1221 TypeVar tv = (TypeVar) t;
1222 if (s.tag == TYPEVAR)
1223 s = s.getUpperBound();
1224 return !isCastable(tv.bound,
1225 s,
1226 Warner.noWarnings);
1227 }
1228 if (s.tag != WILDCARD)
1229 s = upperBound(s);
1230 if (s.tag == TYPEVAR)
1231 s = s.getUpperBound();
1233 return !isSubtype(t, s);
1234 }
1235 // </editor-fold>
1237 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1238 public boolean isReifiable(Type t) {
1239 return isReifiable.visit(t);
1240 }
1241 // where
1242 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1244 public Boolean visitType(Type t, Void ignored) {
1245 return true;
1246 }
1248 @Override
1249 public Boolean visitClassType(ClassType t, Void ignored) {
1250 if (!t.isParameterized())
1251 return true;
1253 for (Type param : t.allparams()) {
1254 if (!param.isUnbound())
1255 return false;
1256 }
1257 return true;
1258 }
1260 @Override
1261 public Boolean visitArrayType(ArrayType t, Void ignored) {
1262 return visit(t.elemtype);
1263 }
1265 @Override
1266 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1267 return false;
1268 }
1269 };
1270 // </editor-fold>
1272 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1273 public boolean isArray(Type t) {
1274 while (t.tag == WILDCARD)
1275 t = upperBound(t);
1276 return t.tag == ARRAY;
1277 }
1279 /**
1280 * The element type of an array.
1281 */
1282 public Type elemtype(Type t) {
1283 switch (t.tag) {
1284 case WILDCARD:
1285 return elemtype(upperBound(t));
1286 case ARRAY:
1287 return ((ArrayType)t).elemtype;
1288 case FORALL:
1289 return elemtype(((ForAll)t).qtype);
1290 case ERROR:
1291 return t;
1292 default:
1293 return null;
1294 }
1295 }
1297 /**
1298 * Mapping to take element type of an arraytype
1299 */
1300 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1301 public Type apply(Type t) { return elemtype(t); }
1302 };
1304 /**
1305 * The number of dimensions of an array type.
1306 */
1307 public int dimensions(Type t) {
1308 int result = 0;
1309 while (t.tag == ARRAY) {
1310 result++;
1311 t = elemtype(t);
1312 }
1313 return result;
1314 }
1315 // </editor-fold>
1317 // <editor-fold defaultstate="collapsed" desc="asSuper">
1318 /**
1319 * Return the (most specific) base type of t that starts with the
1320 * given symbol. If none exists, return null.
1321 *
1322 * @param t a type
1323 * @param sym a symbol
1324 */
1325 public Type asSuper(Type t, Symbol sym) {
1326 return asSuper.visit(t, sym);
1327 }
1328 // where
1329 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1331 public Type visitType(Type t, Symbol sym) {
1332 return null;
1333 }
1335 @Override
1336 public Type visitClassType(ClassType t, Symbol sym) {
1337 if (t.tsym == sym)
1338 return t;
1340 Type st = supertype(t);
1341 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1342 Type x = asSuper(st, sym);
1343 if (x != null)
1344 return x;
1345 }
1346 if ((sym.flags() & INTERFACE) != 0) {
1347 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1348 Type x = asSuper(l.head, sym);
1349 if (x != null)
1350 return x;
1351 }
1352 }
1353 return null;
1354 }
1356 @Override
1357 public Type visitArrayType(ArrayType t, Symbol sym) {
1358 return isSubtype(t, sym.type) ? sym.type : null;
1359 }
1361 @Override
1362 public Type visitTypeVar(TypeVar t, Symbol sym) {
1363 if (t.tsym == sym)
1364 return t;
1365 else
1366 return asSuper(t.bound, sym);
1367 }
1369 @Override
1370 public Type visitErrorType(ErrorType t, Symbol sym) {
1371 return t;
1372 }
1373 };
1375 /**
1376 * Return the base type of t or any of its outer types that starts
1377 * with the given symbol. If none exists, return null.
1378 *
1379 * @param t a type
1380 * @param sym a symbol
1381 */
1382 public Type asOuterSuper(Type t, Symbol sym) {
1383 switch (t.tag) {
1384 case CLASS:
1385 do {
1386 Type s = asSuper(t, sym);
1387 if (s != null) return s;
1388 t = t.getEnclosingType();
1389 } while (t.tag == CLASS);
1390 return null;
1391 case ARRAY:
1392 return isSubtype(t, sym.type) ? sym.type : null;
1393 case TYPEVAR:
1394 return asSuper(t, sym);
1395 case ERROR:
1396 return t;
1397 default:
1398 return null;
1399 }
1400 }
1402 /**
1403 * Return the base type of t or any of its enclosing types that
1404 * starts with the given symbol. If none exists, return null.
1405 *
1406 * @param t a type
1407 * @param sym a symbol
1408 */
1409 public Type asEnclosingSuper(Type t, Symbol sym) {
1410 switch (t.tag) {
1411 case CLASS:
1412 do {
1413 Type s = asSuper(t, sym);
1414 if (s != null) return s;
1415 Type outer = t.getEnclosingType();
1416 t = (outer.tag == CLASS) ? outer :
1417 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1418 Type.noType;
1419 } while (t.tag == CLASS);
1420 return null;
1421 case ARRAY:
1422 return isSubtype(t, sym.type) ? sym.type : null;
1423 case TYPEVAR:
1424 return asSuper(t, sym);
1425 case ERROR:
1426 return t;
1427 default:
1428 return null;
1429 }
1430 }
1431 // </editor-fold>
1433 // <editor-fold defaultstate="collapsed" desc="memberType">
1434 /**
1435 * The type of given symbol, seen as a member of t.
1436 *
1437 * @param t a type
1438 * @param sym a symbol
1439 */
1440 public Type memberType(Type t, Symbol sym) {
1441 return (sym.flags() & STATIC) != 0
1442 ? sym.type
1443 : memberType.visit(t, sym);
1444 }
1445 // where
1446 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1448 public Type visitType(Type t, Symbol sym) {
1449 return sym.type;
1450 }
1452 @Override
1453 public Type visitWildcardType(WildcardType t, Symbol sym) {
1454 return memberType(upperBound(t), sym);
1455 }
1457 @Override
1458 public Type visitClassType(ClassType t, Symbol sym) {
1459 Symbol owner = sym.owner;
1460 long flags = sym.flags();
1461 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1462 Type base = asOuterSuper(t, owner);
1463 //if t is an intersection type T = CT & I1 & I2 ... & In
1464 //its supertypes CT, I1, ... In might contain wildcards
1465 //so we need to go through capture conversion
1466 base = t.isCompound() ? capture(base) : base;
1467 if (base != null) {
1468 List<Type> ownerParams = owner.type.allparams();
1469 List<Type> baseParams = base.allparams();
1470 if (ownerParams.nonEmpty()) {
1471 if (baseParams.isEmpty()) {
1472 // then base is a raw type
1473 return erasure(sym.type);
1474 } else {
1475 return subst(sym.type, ownerParams, baseParams);
1476 }
1477 }
1478 }
1479 }
1480 return sym.type;
1481 }
1483 @Override
1484 public Type visitTypeVar(TypeVar t, Symbol sym) {
1485 return memberType(t.bound, sym);
1486 }
1488 @Override
1489 public Type visitErrorType(ErrorType t, Symbol sym) {
1490 return t;
1491 }
1492 };
1493 // </editor-fold>
1495 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1496 public boolean isAssignable(Type t, Type s) {
1497 return isAssignable(t, s, Warner.noWarnings);
1498 }
1500 /**
1501 * Is t assignable to s?<br>
1502 * Equivalent to subtype except for constant values and raw
1503 * types.<br>
1504 * (not defined for Method and ForAll types)
1505 */
1506 public boolean isAssignable(Type t, Type s, Warner warn) {
1507 if (t.tag == ERROR)
1508 return true;
1509 if (t.tag <= INT && t.constValue() != null) {
1510 int value = ((Number)t.constValue()).intValue();
1511 switch (s.tag) {
1512 case BYTE:
1513 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1514 return true;
1515 break;
1516 case CHAR:
1517 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1518 return true;
1519 break;
1520 case SHORT:
1521 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1522 return true;
1523 break;
1524 case INT:
1525 return true;
1526 case CLASS:
1527 switch (unboxedType(s).tag) {
1528 case BYTE:
1529 case CHAR:
1530 case SHORT:
1531 return isAssignable(t, unboxedType(s), warn);
1532 }
1533 break;
1534 }
1535 }
1536 return isConvertible(t, s, warn);
1537 }
1538 // </editor-fold>
1540 // <editor-fold defaultstate="collapsed" desc="erasure">
1541 /**
1542 * The erasure of t {@code |t|} -- the type that results when all
1543 * type parameters in t are deleted.
1544 */
1545 public Type erasure(Type t) {
1546 return erasure(t, false);
1547 }
1548 //where
1549 private Type erasure(Type t, boolean recurse) {
1550 if (t.tag <= lastBaseTag)
1551 return t; /* fast special case */
1552 else
1553 return erasure.visit(t, recurse);
1554 }
1555 // where
1556 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
1557 public Type visitType(Type t, Boolean recurse) {
1558 if (t.tag <= lastBaseTag)
1559 return t; /*fast special case*/
1560 else
1561 return t.map(recurse ? erasureRecFun : erasureFun);
1562 }
1564 @Override
1565 public Type visitWildcardType(WildcardType t, Boolean recurse) {
1566 return erasure(upperBound(t), recurse);
1567 }
1569 @Override
1570 public Type visitClassType(ClassType t, Boolean recurse) {
1571 Type erased = t.tsym.erasure(Types.this);
1572 if (recurse) {
1573 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
1574 }
1575 return erased;
1576 }
1578 @Override
1579 public Type visitTypeVar(TypeVar t, Boolean recurse) {
1580 return erasure(t.bound, recurse);
1581 }
1583 @Override
1584 public Type visitErrorType(ErrorType t, Boolean recurse) {
1585 return t;
1586 }
1587 };
1589 private Mapping erasureFun = new Mapping ("erasure") {
1590 public Type apply(Type t) { return erasure(t); }
1591 };
1593 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
1594 public Type apply(Type t) { return erasureRecursive(t); }
1595 };
1597 public List<Type> erasure(List<Type> ts) {
1598 return Type.map(ts, erasureFun);
1599 }
1601 public Type erasureRecursive(Type t) {
1602 return erasure(t, true);
1603 }
1605 public List<Type> erasureRecursive(List<Type> ts) {
1606 return Type.map(ts, erasureRecFun);
1607 }
1608 // </editor-fold>
1610 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
1611 /**
1612 * Make a compound type from non-empty list of types
1613 *
1614 * @param bounds the types from which the compound type is formed
1615 * @param supertype is objectType if all bounds are interfaces,
1616 * null otherwise.
1617 */
1618 public Type makeCompoundType(List<Type> bounds,
1619 Type supertype) {
1620 ClassSymbol bc =
1621 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
1622 Type.moreInfo
1623 ? names.fromString(bounds.toString())
1624 : names.empty,
1625 syms.noSymbol);
1626 if (bounds.head.tag == TYPEVAR)
1627 // error condition, recover
1628 bc.erasure_field = syms.objectType;
1629 else
1630 bc.erasure_field = erasure(bounds.head);
1631 bc.members_field = new Scope(bc);
1632 ClassType bt = (ClassType)bc.type;
1633 bt.allparams_field = List.nil();
1634 if (supertype != null) {
1635 bt.supertype_field = supertype;
1636 bt.interfaces_field = bounds;
1637 } else {
1638 bt.supertype_field = bounds.head;
1639 bt.interfaces_field = bounds.tail;
1640 }
1641 assert bt.supertype_field.tsym.completer != null
1642 || !bt.supertype_field.isInterface()
1643 : bt.supertype_field;
1644 return bt;
1645 }
1647 /**
1648 * Same as {@link #makeCompoundType(List,Type)}, except that the
1649 * second parameter is computed directly. Note that this might
1650 * cause a symbol completion. Hence, this version of
1651 * makeCompoundType may not be called during a classfile read.
1652 */
1653 public Type makeCompoundType(List<Type> bounds) {
1654 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1655 supertype(bounds.head) : null;
1656 return makeCompoundType(bounds, supertype);
1657 }
1659 /**
1660 * A convenience wrapper for {@link #makeCompoundType(List)}; the
1661 * arguments are converted to a list and passed to the other
1662 * method. Note that this might cause a symbol completion.
1663 * Hence, this version of makeCompoundType may not be called
1664 * during a classfile read.
1665 */
1666 public Type makeCompoundType(Type bound1, Type bound2) {
1667 return makeCompoundType(List.of(bound1, bound2));
1668 }
1669 // </editor-fold>
1671 // <editor-fold defaultstate="collapsed" desc="supertype">
1672 public Type supertype(Type t) {
1673 return supertype.visit(t);
1674 }
1675 // where
1676 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
1678 public Type visitType(Type t, Void ignored) {
1679 // A note on wildcards: there is no good way to
1680 // determine a supertype for a super bounded wildcard.
1681 return null;
1682 }
1684 @Override
1685 public Type visitClassType(ClassType t, Void ignored) {
1686 if (t.supertype_field == null) {
1687 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
1688 // An interface has no superclass; its supertype is Object.
1689 if (t.isInterface())
1690 supertype = ((ClassType)t.tsym.type).supertype_field;
1691 if (t.supertype_field == null) {
1692 List<Type> actuals = classBound(t).allparams();
1693 List<Type> formals = t.tsym.type.allparams();
1694 if (t.hasErasedSupertypes()) {
1695 t.supertype_field = erasureRecursive(supertype);
1696 } else if (formals.nonEmpty()) {
1697 t.supertype_field = subst(supertype, formals, actuals);
1698 }
1699 else {
1700 t.supertype_field = supertype;
1701 }
1702 }
1703 }
1704 return t.supertype_field;
1705 }
1707 /**
1708 * The supertype is always a class type. If the type
1709 * variable's bounds start with a class type, this is also
1710 * the supertype. Otherwise, the supertype is
1711 * java.lang.Object.
1712 */
1713 @Override
1714 public Type visitTypeVar(TypeVar t, Void ignored) {
1715 if (t.bound.tag == TYPEVAR ||
1716 (!t.bound.isCompound() && !t.bound.isInterface())) {
1717 return t.bound;
1718 } else {
1719 return supertype(t.bound);
1720 }
1721 }
1723 @Override
1724 public Type visitArrayType(ArrayType t, Void ignored) {
1725 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
1726 return arraySuperType();
1727 else
1728 return new ArrayType(supertype(t.elemtype), t.tsym);
1729 }
1731 @Override
1732 public Type visitErrorType(ErrorType t, Void ignored) {
1733 return t;
1734 }
1735 };
1736 // </editor-fold>
1738 // <editor-fold defaultstate="collapsed" desc="interfaces">
1739 /**
1740 * Return the interfaces implemented by this class.
1741 */
1742 public List<Type> interfaces(Type t) {
1743 return interfaces.visit(t);
1744 }
1745 // where
1746 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
1748 public List<Type> visitType(Type t, Void ignored) {
1749 return List.nil();
1750 }
1752 @Override
1753 public List<Type> visitClassType(ClassType t, Void ignored) {
1754 if (t.interfaces_field == null) {
1755 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
1756 if (t.interfaces_field == null) {
1757 // If t.interfaces_field is null, then t must
1758 // be a parameterized type (not to be confused
1759 // with a generic type declaration).
1760 // Terminology:
1761 // Parameterized type: List<String>
1762 // Generic type declaration: class List<E> { ... }
1763 // So t corresponds to List<String> and
1764 // t.tsym.type corresponds to List<E>.
1765 // The reason t must be parameterized type is
1766 // that completion will happen as a side
1767 // effect of calling
1768 // ClassSymbol.getInterfaces. Since
1769 // t.interfaces_field is null after
1770 // completion, we can assume that t is not the
1771 // type of a class/interface declaration.
1772 assert t != t.tsym.type : t.toString();
1773 List<Type> actuals = t.allparams();
1774 List<Type> formals = t.tsym.type.allparams();
1775 if (t.hasErasedSupertypes()) {
1776 t.interfaces_field = erasureRecursive(interfaces);
1777 } else if (formals.nonEmpty()) {
1778 t.interfaces_field =
1779 upperBounds(subst(interfaces, formals, actuals));
1780 }
1781 else {
1782 t.interfaces_field = interfaces;
1783 }
1784 }
1785 }
1786 return t.interfaces_field;
1787 }
1789 @Override
1790 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
1791 if (t.bound.isCompound())
1792 return interfaces(t.bound);
1794 if (t.bound.isInterface())
1795 return List.of(t.bound);
1797 return List.nil();
1798 }
1799 };
1800 // </editor-fold>
1802 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
1803 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
1805 public boolean isDerivedRaw(Type t) {
1806 Boolean result = isDerivedRawCache.get(t);
1807 if (result == null) {
1808 result = isDerivedRawInternal(t);
1809 isDerivedRawCache.put(t, result);
1810 }
1811 return result;
1812 }
1814 public boolean isDerivedRawInternal(Type t) {
1815 if (t.isErroneous())
1816 return false;
1817 return
1818 t.isRaw() ||
1819 supertype(t) != null && isDerivedRaw(supertype(t)) ||
1820 isDerivedRaw(interfaces(t));
1821 }
1823 public boolean isDerivedRaw(List<Type> ts) {
1824 List<Type> l = ts;
1825 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
1826 return l.nonEmpty();
1827 }
1828 // </editor-fold>
1830 // <editor-fold defaultstate="collapsed" desc="setBounds">
1831 /**
1832 * Set the bounds field of the given type variable to reflect a
1833 * (possibly multiple) list of bounds.
1834 * @param t a type variable
1835 * @param bounds the bounds, must be nonempty
1836 * @param supertype is objectType if all bounds are interfaces,
1837 * null otherwise.
1838 */
1839 public void setBounds(TypeVar t, List<Type> bounds, Type supertype) {
1840 if (bounds.tail.isEmpty())
1841 t.bound = bounds.head;
1842 else
1843 t.bound = makeCompoundType(bounds, supertype);
1844 t.rank_field = -1;
1845 }
1847 /**
1848 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
1849 * third parameter is computed directly. Note that this test
1850 * might cause a symbol completion. Hence, this version of
1851 * setBounds may not be called during a classfile read.
1852 */
1853 public void setBounds(TypeVar t, List<Type> bounds) {
1854 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1855 supertype(bounds.head) : null;
1856 setBounds(t, bounds, supertype);
1857 t.rank_field = -1;
1858 }
1859 // </editor-fold>
1861 // <editor-fold defaultstate="collapsed" desc="getBounds">
1862 /**
1863 * Return list of bounds of the given type variable.
1864 */
1865 public List<Type> getBounds(TypeVar t) {
1866 if (t.bound.isErroneous() || !t.bound.isCompound())
1867 return List.of(t.bound);
1868 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
1869 return interfaces(t).prepend(supertype(t));
1870 else
1871 // No superclass was given in bounds.
1872 // In this case, supertype is Object, erasure is first interface.
1873 return interfaces(t);
1874 }
1875 // </editor-fold>
1877 // <editor-fold defaultstate="collapsed" desc="classBound">
1878 /**
1879 * If the given type is a (possibly selected) type variable,
1880 * return the bounding class of this type, otherwise return the
1881 * type itself.
1882 */
1883 public Type classBound(Type t) {
1884 return classBound.visit(t);
1885 }
1886 // where
1887 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
1889 public Type visitType(Type t, Void ignored) {
1890 return t;
1891 }
1893 @Override
1894 public Type visitClassType(ClassType t, Void ignored) {
1895 Type outer1 = classBound(t.getEnclosingType());
1896 if (outer1 != t.getEnclosingType())
1897 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
1898 else
1899 return t;
1900 }
1902 @Override
1903 public Type visitTypeVar(TypeVar t, Void ignored) {
1904 return classBound(supertype(t));
1905 }
1907 @Override
1908 public Type visitErrorType(ErrorType t, Void ignored) {
1909 return t;
1910 }
1911 };
1912 // </editor-fold>
1914 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
1915 /**
1916 * Returns true iff the first signature is a <em>sub
1917 * signature</em> of the other. This is <b>not</b> an equivalence
1918 * relation.
1919 *
1920 * @see "The Java Language Specification, Third Ed. (8.4.2)."
1921 * @see #overrideEquivalent(Type t, Type s)
1922 * @param t first signature (possibly raw).
1923 * @param s second signature (could be subjected to erasure).
1924 * @return true if t is a sub signature of s.
1925 */
1926 public boolean isSubSignature(Type t, Type s) {
1927 return hasSameArgs(t, s) || hasSameArgs(t, erasure(s));
1928 }
1930 /**
1931 * Returns true iff these signatures are related by <em>override
1932 * equivalence</em>. This is the natural extension of
1933 * isSubSignature to an equivalence relation.
1934 *
1935 * @see "The Java Language Specification, Third Ed. (8.4.2)."
1936 * @see #isSubSignature(Type t, Type s)
1937 * @param t a signature (possible raw, could be subjected to
1938 * erasure).
1939 * @param s a signature (possible raw, could be subjected to
1940 * erasure).
1941 * @return true if either argument is a sub signature of the other.
1942 */
1943 public boolean overrideEquivalent(Type t, Type s) {
1944 return hasSameArgs(t, s) ||
1945 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
1946 }
1948 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, MethodSymbol>>> implCache_check =
1949 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, MethodSymbol>>>();
1951 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, MethodSymbol>>> implCache_nocheck =
1952 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, MethodSymbol>>>();
1954 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, Types types, boolean checkResult) {
1955 Map<MethodSymbol, SoftReference<Map<TypeSymbol, MethodSymbol>>> implCache = checkResult ?
1956 implCache_check : implCache_nocheck;
1957 SoftReference<Map<TypeSymbol, MethodSymbol>> ref_cache = implCache.get(ms);
1958 Map<TypeSymbol, MethodSymbol> cache = ref_cache != null ? ref_cache.get() : null;
1959 if (cache == null) {
1960 cache = new HashMap<TypeSymbol, MethodSymbol>();
1961 implCache.put(ms, new SoftReference<Map<TypeSymbol, MethodSymbol>>(cache));
1962 }
1963 MethodSymbol impl = cache.get(origin);
1964 if (impl == null) {
1965 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = types.supertype(t)) {
1966 while (t.tag == TYPEVAR)
1967 t = t.getUpperBound();
1968 TypeSymbol c = t.tsym;
1969 for (Scope.Entry e = c.members().lookup(ms.name);
1970 e.scope != null;
1971 e = e.next()) {
1972 if (e.sym.kind == Kinds.MTH) {
1973 MethodSymbol m = (MethodSymbol) e.sym;
1974 if (m.overrides(ms, origin, types, checkResult) &&
1975 (m.flags() & SYNTHETIC) == 0) {
1976 impl = m;
1977 cache.put(origin, m);
1978 return impl;
1979 }
1980 }
1981 }
1982 }
1983 }
1984 return impl;
1985 }
1987 /**
1988 * Does t have the same arguments as s? It is assumed that both
1989 * types are (possibly polymorphic) method types. Monomorphic
1990 * method types "have the same arguments", if their argument lists
1991 * are equal. Polymorphic method types "have the same arguments",
1992 * if they have the same arguments after renaming all type
1993 * variables of one to corresponding type variables in the other,
1994 * where correspondence is by position in the type parameter list.
1995 */
1996 public boolean hasSameArgs(Type t, Type s) {
1997 return hasSameArgs.visit(t, s);
1998 }
1999 // where
2000 private TypeRelation hasSameArgs = new TypeRelation() {
2002 public Boolean visitType(Type t, Type s) {
2003 throw new AssertionError();
2004 }
2006 @Override
2007 public Boolean visitMethodType(MethodType t, Type s) {
2008 return s.tag == METHOD
2009 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2010 }
2012 @Override
2013 public Boolean visitForAll(ForAll t, Type s) {
2014 if (s.tag != FORALL)
2015 return false;
2017 ForAll forAll = (ForAll)s;
2018 return hasSameBounds(t, forAll)
2019 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2020 }
2022 @Override
2023 public Boolean visitErrorType(ErrorType t, Type s) {
2024 return false;
2025 }
2026 };
2027 // </editor-fold>
2029 // <editor-fold defaultstate="collapsed" desc="subst">
2030 public List<Type> subst(List<Type> ts,
2031 List<Type> from,
2032 List<Type> to) {
2033 return new Subst(from, to).subst(ts);
2034 }
2036 /**
2037 * Substitute all occurrences of a type in `from' with the
2038 * corresponding type in `to' in 't'. Match lists `from' and `to'
2039 * from the right: If lists have different length, discard leading
2040 * elements of the longer list.
2041 */
2042 public Type subst(Type t, List<Type> from, List<Type> to) {
2043 return new Subst(from, to).subst(t);
2044 }
2046 private class Subst extends UnaryVisitor<Type> {
2047 List<Type> from;
2048 List<Type> to;
2050 public Subst(List<Type> from, List<Type> to) {
2051 int fromLength = from.length();
2052 int toLength = to.length();
2053 while (fromLength > toLength) {
2054 fromLength--;
2055 from = from.tail;
2056 }
2057 while (fromLength < toLength) {
2058 toLength--;
2059 to = to.tail;
2060 }
2061 this.from = from;
2062 this.to = to;
2063 }
2065 Type subst(Type t) {
2066 if (from.tail == null)
2067 return t;
2068 else
2069 return visit(t);
2070 }
2072 List<Type> subst(List<Type> ts) {
2073 if (from.tail == null)
2074 return ts;
2075 boolean wild = false;
2076 if (ts.nonEmpty() && from.nonEmpty()) {
2077 Type head1 = subst(ts.head);
2078 List<Type> tail1 = subst(ts.tail);
2079 if (head1 != ts.head || tail1 != ts.tail)
2080 return tail1.prepend(head1);
2081 }
2082 return ts;
2083 }
2085 public Type visitType(Type t, Void ignored) {
2086 return t;
2087 }
2089 @Override
2090 public Type visitMethodType(MethodType t, Void ignored) {
2091 List<Type> argtypes = subst(t.argtypes);
2092 Type restype = subst(t.restype);
2093 List<Type> thrown = subst(t.thrown);
2094 if (argtypes == t.argtypes &&
2095 restype == t.restype &&
2096 thrown == t.thrown)
2097 return t;
2098 else
2099 return new MethodType(argtypes, restype, thrown, t.tsym);
2100 }
2102 @Override
2103 public Type visitTypeVar(TypeVar t, Void ignored) {
2104 for (List<Type> from = this.from, to = this.to;
2105 from.nonEmpty();
2106 from = from.tail, to = to.tail) {
2107 if (t == from.head) {
2108 return to.head.withTypeVar(t);
2109 }
2110 }
2111 return t;
2112 }
2114 @Override
2115 public Type visitClassType(ClassType t, Void ignored) {
2116 if (!t.isCompound()) {
2117 List<Type> typarams = t.getTypeArguments();
2118 List<Type> typarams1 = subst(typarams);
2119 Type outer = t.getEnclosingType();
2120 Type outer1 = subst(outer);
2121 if (typarams1 == typarams && outer1 == outer)
2122 return t;
2123 else
2124 return new ClassType(outer1, typarams1, t.tsym);
2125 } else {
2126 Type st = subst(supertype(t));
2127 List<Type> is = upperBounds(subst(interfaces(t)));
2128 if (st == supertype(t) && is == interfaces(t))
2129 return t;
2130 else
2131 return makeCompoundType(is.prepend(st));
2132 }
2133 }
2135 @Override
2136 public Type visitWildcardType(WildcardType t, Void ignored) {
2137 Type bound = t.type;
2138 if (t.kind != BoundKind.UNBOUND)
2139 bound = subst(bound);
2140 if (bound == t.type) {
2141 return t;
2142 } else {
2143 if (t.isExtendsBound() && bound.isExtendsBound())
2144 bound = upperBound(bound);
2145 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2146 }
2147 }
2149 @Override
2150 public Type visitArrayType(ArrayType t, Void ignored) {
2151 Type elemtype = subst(t.elemtype);
2152 if (elemtype == t.elemtype)
2153 return t;
2154 else
2155 return new ArrayType(upperBound(elemtype), t.tsym);
2156 }
2158 @Override
2159 public Type visitForAll(ForAll t, Void ignored) {
2160 List<Type> tvars1 = substBounds(t.tvars, from, to);
2161 Type qtype1 = subst(t.qtype);
2162 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2163 return t;
2164 } else if (tvars1 == t.tvars) {
2165 return new ForAll(tvars1, qtype1);
2166 } else {
2167 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2168 }
2169 }
2171 @Override
2172 public Type visitErrorType(ErrorType t, Void ignored) {
2173 return t;
2174 }
2175 }
2177 public List<Type> substBounds(List<Type> tvars,
2178 List<Type> from,
2179 List<Type> to) {
2180 if (tvars.isEmpty())
2181 return tvars;
2182 ListBuffer<Type> newBoundsBuf = lb();
2183 boolean changed = false;
2184 // calculate new bounds
2185 for (Type t : tvars) {
2186 TypeVar tv = (TypeVar) t;
2187 Type bound = subst(tv.bound, from, to);
2188 if (bound != tv.bound)
2189 changed = true;
2190 newBoundsBuf.append(bound);
2191 }
2192 if (!changed)
2193 return tvars;
2194 ListBuffer<Type> newTvars = lb();
2195 // create new type variables without bounds
2196 for (Type t : tvars) {
2197 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2198 }
2199 // the new bounds should use the new type variables in place
2200 // of the old
2201 List<Type> newBounds = newBoundsBuf.toList();
2202 from = tvars;
2203 to = newTvars.toList();
2204 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2205 newBounds.head = subst(newBounds.head, from, to);
2206 }
2207 newBounds = newBoundsBuf.toList();
2208 // set the bounds of new type variables to the new bounds
2209 for (Type t : newTvars.toList()) {
2210 TypeVar tv = (TypeVar) t;
2211 tv.bound = newBounds.head;
2212 newBounds = newBounds.tail;
2213 }
2214 return newTvars.toList();
2215 }
2217 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2218 Type bound1 = subst(t.bound, from, to);
2219 if (bound1 == t.bound)
2220 return t;
2221 else {
2222 // create new type variable without bounds
2223 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2224 // the new bound should use the new type variable in place
2225 // of the old
2226 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2227 return tv;
2228 }
2229 }
2230 // </editor-fold>
2232 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2233 /**
2234 * Does t have the same bounds for quantified variables as s?
2235 */
2236 boolean hasSameBounds(ForAll t, ForAll s) {
2237 List<Type> l1 = t.tvars;
2238 List<Type> l2 = s.tvars;
2239 while (l1.nonEmpty() && l2.nonEmpty() &&
2240 isSameType(l1.head.getUpperBound(),
2241 subst(l2.head.getUpperBound(),
2242 s.tvars,
2243 t.tvars))) {
2244 l1 = l1.tail;
2245 l2 = l2.tail;
2246 }
2247 return l1.isEmpty() && l2.isEmpty();
2248 }
2249 // </editor-fold>
2251 // <editor-fold defaultstate="collapsed" desc="newInstances">
2252 /** Create new vector of type variables from list of variables
2253 * changing all recursive bounds from old to new list.
2254 */
2255 public List<Type> newInstances(List<Type> tvars) {
2256 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2257 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2258 TypeVar tv = (TypeVar) l.head;
2259 tv.bound = subst(tv.bound, tvars, tvars1);
2260 }
2261 return tvars1;
2262 }
2263 static private Mapping newInstanceFun = new Mapping("newInstanceFun") {
2264 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2265 };
2266 // </editor-fold>
2268 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2269 public Type createErrorType(Type originalType) {
2270 return new ErrorType(originalType, syms.errSymbol);
2271 }
2273 public Type createErrorType(ClassSymbol c, Type originalType) {
2274 return new ErrorType(c, originalType);
2275 }
2277 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
2278 return new ErrorType(name, container, originalType);
2279 }
2280 // </editor-fold>
2282 // <editor-fold defaultstate="collapsed" desc="rank">
2283 /**
2284 * The rank of a class is the length of the longest path between
2285 * the class and java.lang.Object in the class inheritance
2286 * graph. Undefined for all but reference types.
2287 */
2288 public int rank(Type t) {
2289 switch(t.tag) {
2290 case CLASS: {
2291 ClassType cls = (ClassType)t;
2292 if (cls.rank_field < 0) {
2293 Name fullname = cls.tsym.getQualifiedName();
2294 if (fullname == names.java_lang_Object)
2295 cls.rank_field = 0;
2296 else {
2297 int r = rank(supertype(cls));
2298 for (List<Type> l = interfaces(cls);
2299 l.nonEmpty();
2300 l = l.tail) {
2301 if (rank(l.head) > r)
2302 r = rank(l.head);
2303 }
2304 cls.rank_field = r + 1;
2305 }
2306 }
2307 return cls.rank_field;
2308 }
2309 case TYPEVAR: {
2310 TypeVar tvar = (TypeVar)t;
2311 if (tvar.rank_field < 0) {
2312 int r = rank(supertype(tvar));
2313 for (List<Type> l = interfaces(tvar);
2314 l.nonEmpty();
2315 l = l.tail) {
2316 if (rank(l.head) > r) r = rank(l.head);
2317 }
2318 tvar.rank_field = r + 1;
2319 }
2320 return tvar.rank_field;
2321 }
2322 case ERROR:
2323 return 0;
2324 default:
2325 throw new AssertionError();
2326 }
2327 }
2328 // </editor-fold>
2330 /**
2331 * Helper method for generating a string representation of a given type
2332 * accordingly to a given locale
2333 */
2334 public String toString(Type t, Locale locale) {
2335 return Printer.createStandardPrinter(messages).visit(t, locale);
2336 }
2338 /**
2339 * Helper method for generating a string representation of a given type
2340 * accordingly to a given locale
2341 */
2342 public String toString(Symbol t, Locale locale) {
2343 return Printer.createStandardPrinter(messages).visit(t, locale);
2344 }
2346 // <editor-fold defaultstate="collapsed" desc="toString">
2347 /**
2348 * This toString is slightly more descriptive than the one on Type.
2349 *
2350 * @deprecated Types.toString(Type t, Locale l) provides better support
2351 * for localization
2352 */
2353 @Deprecated
2354 public String toString(Type t) {
2355 if (t.tag == FORALL) {
2356 ForAll forAll = (ForAll)t;
2357 return typaramsString(forAll.tvars) + forAll.qtype;
2358 }
2359 return "" + t;
2360 }
2361 // where
2362 private String typaramsString(List<Type> tvars) {
2363 StringBuffer s = new StringBuffer();
2364 s.append('<');
2365 boolean first = true;
2366 for (Type t : tvars) {
2367 if (!first) s.append(", ");
2368 first = false;
2369 appendTyparamString(((TypeVar)t), s);
2370 }
2371 s.append('>');
2372 return s.toString();
2373 }
2374 private void appendTyparamString(TypeVar t, StringBuffer buf) {
2375 buf.append(t);
2376 if (t.bound == null ||
2377 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
2378 return;
2379 buf.append(" extends "); // Java syntax; no need for i18n
2380 Type bound = t.bound;
2381 if (!bound.isCompound()) {
2382 buf.append(bound);
2383 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
2384 buf.append(supertype(t));
2385 for (Type intf : interfaces(t)) {
2386 buf.append('&');
2387 buf.append(intf);
2388 }
2389 } else {
2390 // No superclass was given in bounds.
2391 // In this case, supertype is Object, erasure is first interface.
2392 boolean first = true;
2393 for (Type intf : interfaces(t)) {
2394 if (!first) buf.append('&');
2395 first = false;
2396 buf.append(intf);
2397 }
2398 }
2399 }
2400 // </editor-fold>
2402 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
2403 /**
2404 * A cache for closures.
2405 *
2406 * <p>A closure is a list of all the supertypes and interfaces of
2407 * a class or interface type, ordered by ClassSymbol.precedes
2408 * (that is, subclasses come first, arbitrary but fixed
2409 * otherwise).
2410 */
2411 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
2413 /**
2414 * Returns the closure of a class or interface type.
2415 */
2416 public List<Type> closure(Type t) {
2417 List<Type> cl = closureCache.get(t);
2418 if (cl == null) {
2419 Type st = supertype(t);
2420 if (!t.isCompound()) {
2421 if (st.tag == CLASS) {
2422 cl = insert(closure(st), t);
2423 } else if (st.tag == TYPEVAR) {
2424 cl = closure(st).prepend(t);
2425 } else {
2426 cl = List.of(t);
2427 }
2428 } else {
2429 cl = closure(supertype(t));
2430 }
2431 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
2432 cl = union(cl, closure(l.head));
2433 closureCache.put(t, cl);
2434 }
2435 return cl;
2436 }
2438 /**
2439 * Insert a type in a closure
2440 */
2441 public List<Type> insert(List<Type> cl, Type t) {
2442 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
2443 return cl.prepend(t);
2444 } else if (cl.head.tsym.precedes(t.tsym, this)) {
2445 return insert(cl.tail, t).prepend(cl.head);
2446 } else {
2447 return cl;
2448 }
2449 }
2451 /**
2452 * Form the union of two closures
2453 */
2454 public List<Type> union(List<Type> cl1, List<Type> cl2) {
2455 if (cl1.isEmpty()) {
2456 return cl2;
2457 } else if (cl2.isEmpty()) {
2458 return cl1;
2459 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
2460 return union(cl1.tail, cl2).prepend(cl1.head);
2461 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
2462 return union(cl1, cl2.tail).prepend(cl2.head);
2463 } else {
2464 return union(cl1.tail, cl2.tail).prepend(cl1.head);
2465 }
2466 }
2468 /**
2469 * Intersect two closures
2470 */
2471 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
2472 if (cl1 == cl2)
2473 return cl1;
2474 if (cl1.isEmpty() || cl2.isEmpty())
2475 return List.nil();
2476 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
2477 return intersect(cl1.tail, cl2);
2478 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
2479 return intersect(cl1, cl2.tail);
2480 if (isSameType(cl1.head, cl2.head))
2481 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
2482 if (cl1.head.tsym == cl2.head.tsym &&
2483 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
2484 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
2485 Type merge = merge(cl1.head,cl2.head);
2486 return intersect(cl1.tail, cl2.tail).prepend(merge);
2487 }
2488 if (cl1.head.isRaw() || cl2.head.isRaw())
2489 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
2490 }
2491 return intersect(cl1.tail, cl2.tail);
2492 }
2493 // where
2494 class TypePair {
2495 final Type t1;
2496 final Type t2;
2497 TypePair(Type t1, Type t2) {
2498 this.t1 = t1;
2499 this.t2 = t2;
2500 }
2501 @Override
2502 public int hashCode() {
2503 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
2504 }
2505 @Override
2506 public boolean equals(Object obj) {
2507 if (!(obj instanceof TypePair))
2508 return false;
2509 TypePair typePair = (TypePair)obj;
2510 return isSameType(t1, typePair.t1)
2511 && isSameType(t2, typePair.t2);
2512 }
2513 }
2514 Set<TypePair> mergeCache = new HashSet<TypePair>();
2515 private Type merge(Type c1, Type c2) {
2516 ClassType class1 = (ClassType) c1;
2517 List<Type> act1 = class1.getTypeArguments();
2518 ClassType class2 = (ClassType) c2;
2519 List<Type> act2 = class2.getTypeArguments();
2520 ListBuffer<Type> merged = new ListBuffer<Type>();
2521 List<Type> typarams = class1.tsym.type.getTypeArguments();
2523 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
2524 if (containsType(act1.head, act2.head)) {
2525 merged.append(act1.head);
2526 } else if (containsType(act2.head, act1.head)) {
2527 merged.append(act2.head);
2528 } else {
2529 TypePair pair = new TypePair(c1, c2);
2530 Type m;
2531 if (mergeCache.add(pair)) {
2532 m = new WildcardType(lub(upperBound(act1.head),
2533 upperBound(act2.head)),
2534 BoundKind.EXTENDS,
2535 syms.boundClass);
2536 mergeCache.remove(pair);
2537 } else {
2538 m = new WildcardType(syms.objectType,
2539 BoundKind.UNBOUND,
2540 syms.boundClass);
2541 }
2542 merged.append(m.withTypeVar(typarams.head));
2543 }
2544 act1 = act1.tail;
2545 act2 = act2.tail;
2546 typarams = typarams.tail;
2547 }
2548 assert(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
2549 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
2550 }
2552 /**
2553 * Return the minimum type of a closure, a compound type if no
2554 * unique minimum exists.
2555 */
2556 private Type compoundMin(List<Type> cl) {
2557 if (cl.isEmpty()) return syms.objectType;
2558 List<Type> compound = closureMin(cl);
2559 if (compound.isEmpty())
2560 return null;
2561 else if (compound.tail.isEmpty())
2562 return compound.head;
2563 else
2564 return makeCompoundType(compound);
2565 }
2567 /**
2568 * Return the minimum types of a closure, suitable for computing
2569 * compoundMin or glb.
2570 */
2571 private List<Type> closureMin(List<Type> cl) {
2572 ListBuffer<Type> classes = lb();
2573 ListBuffer<Type> interfaces = lb();
2574 while (!cl.isEmpty()) {
2575 Type current = cl.head;
2576 if (current.isInterface())
2577 interfaces.append(current);
2578 else
2579 classes.append(current);
2580 ListBuffer<Type> candidates = lb();
2581 for (Type t : cl.tail) {
2582 if (!isSubtypeNoCapture(current, t))
2583 candidates.append(t);
2584 }
2585 cl = candidates.toList();
2586 }
2587 return classes.appendList(interfaces).toList();
2588 }
2590 /**
2591 * Return the least upper bound of pair of types. if the lub does
2592 * not exist return null.
2593 */
2594 public Type lub(Type t1, Type t2) {
2595 return lub(List.of(t1, t2));
2596 }
2598 /**
2599 * Return the least upper bound (lub) of set of types. If the lub
2600 * does not exist return the type of null (bottom).
2601 */
2602 public Type lub(List<Type> ts) {
2603 final int ARRAY_BOUND = 1;
2604 final int CLASS_BOUND = 2;
2605 int boundkind = 0;
2606 for (Type t : ts) {
2607 switch (t.tag) {
2608 case CLASS:
2609 boundkind |= CLASS_BOUND;
2610 break;
2611 case ARRAY:
2612 boundkind |= ARRAY_BOUND;
2613 break;
2614 case TYPEVAR:
2615 do {
2616 t = t.getUpperBound();
2617 } while (t.tag == TYPEVAR);
2618 if (t.tag == ARRAY) {
2619 boundkind |= ARRAY_BOUND;
2620 } else {
2621 boundkind |= CLASS_BOUND;
2622 }
2623 break;
2624 default:
2625 if (t.isPrimitive())
2626 return syms.errType;
2627 }
2628 }
2629 switch (boundkind) {
2630 case 0:
2631 return syms.botType;
2633 case ARRAY_BOUND:
2634 // calculate lub(A[], B[])
2635 List<Type> elements = Type.map(ts, elemTypeFun);
2636 for (Type t : elements) {
2637 if (t.isPrimitive()) {
2638 // if a primitive type is found, then return
2639 // arraySuperType unless all the types are the
2640 // same
2641 Type first = ts.head;
2642 for (Type s : ts.tail) {
2643 if (!isSameType(first, s)) {
2644 // lub(int[], B[]) is Cloneable & Serializable
2645 return arraySuperType();
2646 }
2647 }
2648 // all the array types are the same, return one
2649 // lub(int[], int[]) is int[]
2650 return first;
2651 }
2652 }
2653 // lub(A[], B[]) is lub(A, B)[]
2654 return new ArrayType(lub(elements), syms.arrayClass);
2656 case CLASS_BOUND:
2657 // calculate lub(A, B)
2658 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
2659 ts = ts.tail;
2660 assert !ts.isEmpty();
2661 List<Type> cl = closure(ts.head);
2662 for (Type t : ts.tail) {
2663 if (t.tag == CLASS || t.tag == TYPEVAR)
2664 cl = intersect(cl, closure(t));
2665 }
2666 return compoundMin(cl);
2668 default:
2669 // calculate lub(A, B[])
2670 List<Type> classes = List.of(arraySuperType());
2671 for (Type t : ts) {
2672 if (t.tag != ARRAY) // Filter out any arrays
2673 classes = classes.prepend(t);
2674 }
2675 // lub(A, B[]) is lub(A, arraySuperType)
2676 return lub(classes);
2677 }
2678 }
2679 // where
2680 private Type arraySuperType = null;
2681 private Type arraySuperType() {
2682 // initialized lazily to avoid problems during compiler startup
2683 if (arraySuperType == null) {
2684 synchronized (this) {
2685 if (arraySuperType == null) {
2686 // JLS 10.8: all arrays implement Cloneable and Serializable.
2687 arraySuperType = makeCompoundType(List.of(syms.serializableType,
2688 syms.cloneableType),
2689 syms.objectType);
2690 }
2691 }
2692 }
2693 return arraySuperType;
2694 }
2695 // </editor-fold>
2697 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
2698 public Type glb(List<Type> ts) {
2699 Type t1 = ts.head;
2700 for (Type t2 : ts.tail) {
2701 if (t1.isErroneous())
2702 return t1;
2703 t1 = glb(t1, t2);
2704 }
2705 return t1;
2706 }
2707 //where
2708 public Type glb(Type t, Type s) {
2709 if (s == null)
2710 return t;
2711 else if (isSubtypeNoCapture(t, s))
2712 return t;
2713 else if (isSubtypeNoCapture(s, t))
2714 return s;
2716 List<Type> closure = union(closure(t), closure(s));
2717 List<Type> bounds = closureMin(closure);
2719 if (bounds.isEmpty()) { // length == 0
2720 return syms.objectType;
2721 } else if (bounds.tail.isEmpty()) { // length == 1
2722 return bounds.head;
2723 } else { // length > 1
2724 int classCount = 0;
2725 for (Type bound : bounds)
2726 if (!bound.isInterface())
2727 classCount++;
2728 if (classCount > 1)
2729 return createErrorType(t);
2730 }
2731 return makeCompoundType(bounds);
2732 }
2733 // </editor-fold>
2735 // <editor-fold defaultstate="collapsed" desc="hashCode">
2736 /**
2737 * Compute a hash code on a type.
2738 */
2739 public static int hashCode(Type t) {
2740 return hashCode.visit(t);
2741 }
2742 // where
2743 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
2745 public Integer visitType(Type t, Void ignored) {
2746 return t.tag;
2747 }
2749 @Override
2750 public Integer visitClassType(ClassType t, Void ignored) {
2751 int result = visit(t.getEnclosingType());
2752 result *= 127;
2753 result += t.tsym.flatName().hashCode();
2754 for (Type s : t.getTypeArguments()) {
2755 result *= 127;
2756 result += visit(s);
2757 }
2758 return result;
2759 }
2761 @Override
2762 public Integer visitWildcardType(WildcardType t, Void ignored) {
2763 int result = t.kind.hashCode();
2764 if (t.type != null) {
2765 result *= 127;
2766 result += visit(t.type);
2767 }
2768 return result;
2769 }
2771 @Override
2772 public Integer visitArrayType(ArrayType t, Void ignored) {
2773 return visit(t.elemtype) + 12;
2774 }
2776 @Override
2777 public Integer visitTypeVar(TypeVar t, Void ignored) {
2778 return System.identityHashCode(t.tsym);
2779 }
2781 @Override
2782 public Integer visitUndetVar(UndetVar t, Void ignored) {
2783 return System.identityHashCode(t);
2784 }
2786 @Override
2787 public Integer visitErrorType(ErrorType t, Void ignored) {
2788 return 0;
2789 }
2790 };
2791 // </editor-fold>
2793 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
2794 /**
2795 * Does t have a result that is a subtype of the result type of s,
2796 * suitable for covariant returns? It is assumed that both types
2797 * are (possibly polymorphic) method types. Monomorphic method
2798 * types are handled in the obvious way. Polymorphic method types
2799 * require renaming all type variables of one to corresponding
2800 * type variables in the other, where correspondence is by
2801 * position in the type parameter list. */
2802 public boolean resultSubtype(Type t, Type s, Warner warner) {
2803 List<Type> tvars = t.getTypeArguments();
2804 List<Type> svars = s.getTypeArguments();
2805 Type tres = t.getReturnType();
2806 Type sres = subst(s.getReturnType(), svars, tvars);
2807 return covariantReturnType(tres, sres, warner);
2808 }
2810 /**
2811 * Return-Type-Substitutable.
2812 * @see <a href="http://java.sun.com/docs/books/jls/">The Java
2813 * Language Specification, Third Ed. (8.4.5)</a>
2814 */
2815 public boolean returnTypeSubstitutable(Type r1, Type r2) {
2816 if (hasSameArgs(r1, r2))
2817 return resultSubtype(r1, r2, Warner.noWarnings);
2818 else
2819 return covariantReturnType(r1.getReturnType(),
2820 erasure(r2.getReturnType()),
2821 Warner.noWarnings);
2822 }
2824 public boolean returnTypeSubstitutable(Type r1,
2825 Type r2, Type r2res,
2826 Warner warner) {
2827 if (isSameType(r1.getReturnType(), r2res))
2828 return true;
2829 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
2830 return false;
2832 if (hasSameArgs(r1, r2))
2833 return covariantReturnType(r1.getReturnType(), r2res, warner);
2834 if (!source.allowCovariantReturns())
2835 return false;
2836 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
2837 return true;
2838 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
2839 return false;
2840 warner.warnUnchecked();
2841 return true;
2842 }
2844 /**
2845 * Is t an appropriate return type in an overrider for a
2846 * method that returns s?
2847 */
2848 public boolean covariantReturnType(Type t, Type s, Warner warner) {
2849 return
2850 isSameType(t, s) ||
2851 source.allowCovariantReturns() &&
2852 !t.isPrimitive() &&
2853 !s.isPrimitive() &&
2854 isAssignable(t, s, warner);
2855 }
2856 // </editor-fold>
2858 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
2859 /**
2860 * Return the class that boxes the given primitive.
2861 */
2862 public ClassSymbol boxedClass(Type t) {
2863 return reader.enterClass(syms.boxedName[t.tag]);
2864 }
2866 /**
2867 * Return the primitive type corresponding to a boxed type.
2868 */
2869 public Type unboxedType(Type t) {
2870 if (allowBoxing) {
2871 for (int i=0; i<syms.boxedName.length; i++) {
2872 Name box = syms.boxedName[i];
2873 if (box != null &&
2874 asSuper(t, reader.enterClass(box)) != null)
2875 return syms.typeOfTag[i];
2876 }
2877 }
2878 return Type.noType;
2879 }
2880 // </editor-fold>
2882 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
2883 /*
2884 * JLS 3rd Ed. 5.1.10 Capture Conversion:
2885 *
2886 * Let G name a generic type declaration with n formal type
2887 * parameters A1 ... An with corresponding bounds U1 ... Un. There
2888 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
2889 * where, for 1 <= i <= n:
2890 *
2891 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
2892 * Si is a fresh type variable whose upper bound is
2893 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
2894 * type.
2895 *
2896 * + If Ti is a wildcard type argument of the form ? extends Bi,
2897 * then Si is a fresh type variable whose upper bound is
2898 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
2899 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
2900 * a compile-time error if for any two classes (not interfaces)
2901 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
2902 *
2903 * + If Ti is a wildcard type argument of the form ? super Bi,
2904 * then Si is a fresh type variable whose upper bound is
2905 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
2906 *
2907 * + Otherwise, Si = Ti.
2908 *
2909 * Capture conversion on any type other than a parameterized type
2910 * (4.5) acts as an identity conversion (5.1.1). Capture
2911 * conversions never require a special action at run time and
2912 * therefore never throw an exception at run time.
2913 *
2914 * Capture conversion is not applied recursively.
2915 */
2916 /**
2917 * Capture conversion as specified by JLS 3rd Ed.
2918 */
2920 public List<Type> capture(List<Type> ts) {
2921 List<Type> buf = List.nil();
2922 for (Type t : ts) {
2923 buf = buf.prepend(capture(t));
2924 }
2925 return buf.reverse();
2926 }
2927 public Type capture(Type t) {
2928 if (t.tag != CLASS)
2929 return t;
2930 ClassType cls = (ClassType)t;
2931 if (cls.isRaw() || !cls.isParameterized())
2932 return cls;
2934 ClassType G = (ClassType)cls.asElement().asType();
2935 List<Type> A = G.getTypeArguments();
2936 List<Type> T = cls.getTypeArguments();
2937 List<Type> S = freshTypeVariables(T);
2939 List<Type> currentA = A;
2940 List<Type> currentT = T;
2941 List<Type> currentS = S;
2942 boolean captured = false;
2943 while (!currentA.isEmpty() &&
2944 !currentT.isEmpty() &&
2945 !currentS.isEmpty()) {
2946 if (currentS.head != currentT.head) {
2947 captured = true;
2948 WildcardType Ti = (WildcardType)currentT.head;
2949 Type Ui = currentA.head.getUpperBound();
2950 CapturedType Si = (CapturedType)currentS.head;
2951 if (Ui == null)
2952 Ui = syms.objectType;
2953 switch (Ti.kind) {
2954 case UNBOUND:
2955 Si.bound = subst(Ui, A, S);
2956 Si.lower = syms.botType;
2957 break;
2958 case EXTENDS:
2959 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
2960 Si.lower = syms.botType;
2961 break;
2962 case SUPER:
2963 Si.bound = subst(Ui, A, S);
2964 Si.lower = Ti.getSuperBound();
2965 break;
2966 }
2967 if (Si.bound == Si.lower)
2968 currentS.head = Si.bound;
2969 }
2970 currentA = currentA.tail;
2971 currentT = currentT.tail;
2972 currentS = currentS.tail;
2973 }
2974 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
2975 return erasure(t); // some "rare" type involved
2977 if (captured)
2978 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
2979 else
2980 return t;
2981 }
2982 // where
2983 public List<Type> freshTypeVariables(List<Type> types) {
2984 ListBuffer<Type> result = lb();
2985 for (Type t : types) {
2986 if (t.tag == WILDCARD) {
2987 Type bound = ((WildcardType)t).getExtendsBound();
2988 if (bound == null)
2989 bound = syms.objectType;
2990 result.append(new CapturedType(capturedName,
2991 syms.noSymbol,
2992 bound,
2993 syms.botType,
2994 (WildcardType)t));
2995 } else {
2996 result.append(t);
2997 }
2998 }
2999 return result.toList();
3000 }
3001 // </editor-fold>
3003 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3004 private List<Type> upperBounds(List<Type> ss) {
3005 if (ss.isEmpty()) return ss;
3006 Type head = upperBound(ss.head);
3007 List<Type> tail = upperBounds(ss.tail);
3008 if (head != ss.head || tail != ss.tail)
3009 return tail.prepend(head);
3010 else
3011 return ss;
3012 }
3014 private boolean sideCast(Type from, Type to, Warner warn) {
3015 // We are casting from type $from$ to type $to$, which are
3016 // non-final unrelated types. This method
3017 // tries to reject a cast by transferring type parameters
3018 // from $to$ to $from$ by common superinterfaces.
3019 boolean reverse = false;
3020 Type target = to;
3021 if ((to.tsym.flags() & INTERFACE) == 0) {
3022 assert (from.tsym.flags() & INTERFACE) != 0;
3023 reverse = true;
3024 to = from;
3025 from = target;
3026 }
3027 List<Type> commonSupers = superClosure(to, erasure(from));
3028 boolean giveWarning = commonSupers.isEmpty();
3029 // The arguments to the supers could be unified here to
3030 // get a more accurate analysis
3031 while (commonSupers.nonEmpty()) {
3032 Type t1 = asSuper(from, commonSupers.head.tsym);
3033 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3034 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3035 return false;
3036 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3037 commonSupers = commonSupers.tail;
3038 }
3039 if (giveWarning && !isReifiable(reverse ? from : to))
3040 warn.warnUnchecked();
3041 if (!source.allowCovariantReturns())
3042 // reject if there is a common method signature with
3043 // incompatible return types.
3044 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3045 return true;
3046 }
3048 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3049 // We are casting from type $from$ to type $to$, which are
3050 // unrelated types one of which is final and the other of
3051 // which is an interface. This method
3052 // tries to reject a cast by transferring type parameters
3053 // from the final class to the interface.
3054 boolean reverse = false;
3055 Type target = to;
3056 if ((to.tsym.flags() & INTERFACE) == 0) {
3057 assert (from.tsym.flags() & INTERFACE) != 0;
3058 reverse = true;
3059 to = from;
3060 from = target;
3061 }
3062 assert (from.tsym.flags() & FINAL) != 0;
3063 Type t1 = asSuper(from, to.tsym);
3064 if (t1 == null) return false;
3065 Type t2 = to;
3066 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3067 return false;
3068 if (!source.allowCovariantReturns())
3069 // reject if there is a common method signature with
3070 // incompatible return types.
3071 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3072 if (!isReifiable(target) &&
3073 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3074 warn.warnUnchecked();
3075 return true;
3076 }
3078 private boolean giveWarning(Type from, Type to) {
3079 Type subFrom = asSub(from, to.tsym);
3080 return to.isParameterized() &&
3081 (!(isUnbounded(to) ||
3082 isSubtype(from, to) ||
3083 ((subFrom != null) && isSameType(subFrom, to))));
3084 }
3086 private List<Type> superClosure(Type t, Type s) {
3087 List<Type> cl = List.nil();
3088 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3089 if (isSubtype(s, erasure(l.head))) {
3090 cl = insert(cl, l.head);
3091 } else {
3092 cl = union(cl, superClosure(l.head, s));
3093 }
3094 }
3095 return cl;
3096 }
3098 private boolean containsTypeEquivalent(Type t, Type s) {
3099 return
3100 isSameType(t, s) || // shortcut
3101 containsType(t, s) && containsType(s, t);
3102 }
3104 // <editor-fold defaultstate="collapsed" desc="adapt">
3105 /**
3106 * Adapt a type by computing a substitution which maps a source
3107 * type to a target type.
3108 *
3109 * @param source the source type
3110 * @param target the target type
3111 * @param from the type variables of the computed substitution
3112 * @param to the types of the computed substitution.
3113 */
3114 public void adapt(Type source,
3115 Type target,
3116 ListBuffer<Type> from,
3117 ListBuffer<Type> to) throws AdaptFailure {
3118 new Adapter(from, to).adapt(source, target);
3119 }
3121 class Adapter extends SimpleVisitor<Void, Type> {
3123 ListBuffer<Type> from;
3124 ListBuffer<Type> to;
3125 Map<Symbol,Type> mapping;
3127 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3128 this.from = from;
3129 this.to = to;
3130 mapping = new HashMap<Symbol,Type>();
3131 }
3133 public void adapt(Type source, Type target) throws AdaptFailure {
3134 visit(source, target);
3135 List<Type> fromList = from.toList();
3136 List<Type> toList = to.toList();
3137 while (!fromList.isEmpty()) {
3138 Type val = mapping.get(fromList.head.tsym);
3139 if (toList.head != val)
3140 toList.head = val;
3141 fromList = fromList.tail;
3142 toList = toList.tail;
3143 }
3144 }
3146 @Override
3147 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3148 if (target.tag == CLASS)
3149 adaptRecursive(source.allparams(), target.allparams());
3150 return null;
3151 }
3153 @Override
3154 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3155 if (target.tag == ARRAY)
3156 adaptRecursive(elemtype(source), elemtype(target));
3157 return null;
3158 }
3160 @Override
3161 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3162 if (source.isExtendsBound())
3163 adaptRecursive(upperBound(source), upperBound(target));
3164 else if (source.isSuperBound())
3165 adaptRecursive(lowerBound(source), lowerBound(target));
3166 return null;
3167 }
3169 @Override
3170 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3171 // Check to see if there is
3172 // already a mapping for $source$, in which case
3173 // the old mapping will be merged with the new
3174 Type val = mapping.get(source.tsym);
3175 if (val != null) {
3176 if (val.isSuperBound() && target.isSuperBound()) {
3177 val = isSubtype(lowerBound(val), lowerBound(target))
3178 ? target : val;
3179 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3180 val = isSubtype(upperBound(val), upperBound(target))
3181 ? val : target;
3182 } else if (!isSameType(val, target)) {
3183 throw new AdaptFailure();
3184 }
3185 } else {
3186 val = target;
3187 from.append(source);
3188 to.append(target);
3189 }
3190 mapping.put(source.tsym, val);
3191 return null;
3192 }
3194 @Override
3195 public Void visitType(Type source, Type target) {
3196 return null;
3197 }
3199 private Set<TypePair> cache = new HashSet<TypePair>();
3201 private void adaptRecursive(Type source, Type target) {
3202 TypePair pair = new TypePair(source, target);
3203 if (cache.add(pair)) {
3204 try {
3205 visit(source, target);
3206 } finally {
3207 cache.remove(pair);
3208 }
3209 }
3210 }
3212 private void adaptRecursive(List<Type> source, List<Type> target) {
3213 if (source.length() == target.length()) {
3214 while (source.nonEmpty()) {
3215 adaptRecursive(source.head, target.head);
3216 source = source.tail;
3217 target = target.tail;
3218 }
3219 }
3220 }
3221 }
3223 public static class AdaptFailure extends RuntimeException {
3224 static final long serialVersionUID = -7490231548272701566L;
3225 }
3227 private void adaptSelf(Type t,
3228 ListBuffer<Type> from,
3229 ListBuffer<Type> to) {
3230 try {
3231 //if (t.tsym.type != t)
3232 adapt(t.tsym.type, t, from, to);
3233 } catch (AdaptFailure ex) {
3234 // Adapt should never fail calculating a mapping from
3235 // t.tsym.type to t as there can be no merge problem.
3236 throw new AssertionError(ex);
3237 }
3238 }
3239 // </editor-fold>
3241 /**
3242 * Rewrite all type variables (universal quantifiers) in the given
3243 * type to wildcards (existential quantifiers). This is used to
3244 * determine if a cast is allowed. For example, if high is true
3245 * and {@code T <: Number}, then {@code List<T>} is rewritten to
3246 * {@code List<? extends Number>}. Since {@code List<Integer> <:
3247 * List<? extends Number>} a {@code List<T>} can be cast to {@code
3248 * List<Integer>} with a warning.
3249 * @param t a type
3250 * @param high if true return an upper bound; otherwise a lower
3251 * bound
3252 * @param rewriteTypeVars only rewrite captured wildcards if false;
3253 * otherwise rewrite all type variables
3254 * @return the type rewritten with wildcards (existential
3255 * quantifiers) only
3256 */
3257 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
3258 return new Rewriter(high, rewriteTypeVars).rewrite(t);
3259 }
3261 class Rewriter extends UnaryVisitor<Type> {
3263 boolean high;
3264 boolean rewriteTypeVars;
3266 Rewriter(boolean high, boolean rewriteTypeVars) {
3267 this.high = high;
3268 this.rewriteTypeVars = rewriteTypeVars;
3269 }
3271 Type rewrite(Type t) {
3272 ListBuffer<Type> from = new ListBuffer<Type>();
3273 ListBuffer<Type> to = new ListBuffer<Type>();
3274 adaptSelf(t, from, to);
3275 ListBuffer<Type> rewritten = new ListBuffer<Type>();
3276 List<Type> formals = from.toList();
3277 boolean changed = false;
3278 for (Type arg : to.toList()) {
3279 Type bound = visit(arg);
3280 if (arg != bound) {
3281 changed = true;
3282 bound = high ? makeExtendsWildcard(bound, (TypeVar)formals.head)
3283 : makeSuperWildcard(bound, (TypeVar)formals.head);
3284 }
3285 rewritten.append(bound);
3286 formals = formals.tail;
3287 }
3288 if (changed)
3289 return subst(t.tsym.type, from.toList(), rewritten.toList());
3290 else
3291 return t;
3292 }
3294 public Type visitType(Type t, Void s) {
3295 return high ? upperBound(t) : lowerBound(t);
3296 }
3298 @Override
3299 public Type visitCapturedType(CapturedType t, Void s) {
3300 return visitWildcardType(t.wildcard, null);
3301 }
3303 @Override
3304 public Type visitTypeVar(TypeVar t, Void s) {
3305 if (rewriteTypeVars)
3306 return high ? t.bound : syms.botType;
3307 else
3308 return t;
3309 }
3311 @Override
3312 public Type visitWildcardType(WildcardType t, Void s) {
3313 Type bound = high ? t.getExtendsBound() :
3314 t.getSuperBound();
3315 if (bound == null)
3316 bound = high ? syms.objectType : syms.botType;
3317 return bound;
3318 }
3319 }
3321 /**
3322 * Create a wildcard with the given upper (extends) bound; create
3323 * an unbounded wildcard if bound is Object.
3324 *
3325 * @param bound the upper bound
3326 * @param formal the formal type parameter that will be
3327 * substituted by the wildcard
3328 */
3329 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
3330 if (bound == syms.objectType) {
3331 return new WildcardType(syms.objectType,
3332 BoundKind.UNBOUND,
3333 syms.boundClass,
3334 formal);
3335 } else {
3336 return new WildcardType(bound,
3337 BoundKind.EXTENDS,
3338 syms.boundClass,
3339 formal);
3340 }
3341 }
3343 /**
3344 * Create a wildcard with the given lower (super) bound; create an
3345 * unbounded wildcard if bound is bottom (type of {@code null}).
3346 *
3347 * @param bound the lower bound
3348 * @param formal the formal type parameter that will be
3349 * substituted by the wildcard
3350 */
3351 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
3352 if (bound.tag == BOT) {
3353 return new WildcardType(syms.objectType,
3354 BoundKind.UNBOUND,
3355 syms.boundClass,
3356 formal);
3357 } else {
3358 return new WildcardType(bound,
3359 BoundKind.SUPER,
3360 syms.boundClass,
3361 formal);
3362 }
3363 }
3365 /**
3366 * A wrapper for a type that allows use in sets.
3367 */
3368 class SingletonType {
3369 final Type t;
3370 SingletonType(Type t) {
3371 this.t = t;
3372 }
3373 public int hashCode() {
3374 return Types.this.hashCode(t);
3375 }
3376 public boolean equals(Object obj) {
3377 return (obj instanceof SingletonType) &&
3378 isSameType(t, ((SingletonType)obj).t);
3379 }
3380 public String toString() {
3381 return t.toString();
3382 }
3383 }
3384 // </editor-fold>
3386 // <editor-fold defaultstate="collapsed" desc="Visitors">
3387 /**
3388 * A default visitor for types. All visitor methods except
3389 * visitType are implemented by delegating to visitType. Concrete
3390 * subclasses must provide an implementation of visitType and can
3391 * override other methods as needed.
3392 *
3393 * @param <R> the return type of the operation implemented by this
3394 * visitor; use Void if no return type is needed.
3395 * @param <S> the type of the second argument (the first being the
3396 * type itself) of the operation implemented by this visitor; use
3397 * Void if a second argument is not needed.
3398 */
3399 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
3400 final public R visit(Type t, S s) { return t.accept(this, s); }
3401 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
3402 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
3403 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
3404 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
3405 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
3406 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
3407 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
3408 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
3409 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
3410 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
3411 }
3413 /**
3414 * A default visitor for symbols. All visitor methods except
3415 * visitSymbol are implemented by delegating to visitSymbol. Concrete
3416 * subclasses must provide an implementation of visitSymbol and can
3417 * override other methods as needed.
3418 *
3419 * @param <R> the return type of the operation implemented by this
3420 * visitor; use Void if no return type is needed.
3421 * @param <S> the type of the second argument (the first being the
3422 * symbol itself) of the operation implemented by this visitor; use
3423 * Void if a second argument is not needed.
3424 */
3425 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
3426 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
3427 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
3428 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
3429 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
3430 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
3431 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
3432 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
3433 }
3435 /**
3436 * A <em>simple</em> visitor for types. This visitor is simple as
3437 * captured wildcards, for-all types (generic methods), and
3438 * undetermined type variables (part of inference) are hidden.
3439 * Captured wildcards are hidden by treating them as type
3440 * variables and the rest are hidden by visiting their qtypes.
3441 *
3442 * @param <R> the return type of the operation implemented by this
3443 * visitor; use Void if no return type is needed.
3444 * @param <S> the type of the second argument (the first being the
3445 * type itself) of the operation implemented by this visitor; use
3446 * Void if a second argument is not needed.
3447 */
3448 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
3449 @Override
3450 public R visitCapturedType(CapturedType t, S s) {
3451 return visitTypeVar(t, s);
3452 }
3453 @Override
3454 public R visitForAll(ForAll t, S s) {
3455 return visit(t.qtype, s);
3456 }
3457 @Override
3458 public R visitUndetVar(UndetVar t, S s) {
3459 return visit(t.qtype, s);
3460 }
3461 }
3463 /**
3464 * A plain relation on types. That is a 2-ary function on the
3465 * form Type × Type → Boolean.
3466 * <!-- In plain text: Type x Type -> Boolean -->
3467 */
3468 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
3470 /**
3471 * A convenience visitor for implementing operations that only
3472 * require one argument (the type itself), that is, unary
3473 * operations.
3474 *
3475 * @param <R> the return type of the operation implemented by this
3476 * visitor; use Void if no return type is needed.
3477 */
3478 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
3479 final public R visit(Type t) { return t.accept(this, null); }
3480 }
3482 /**
3483 * A visitor for implementing a mapping from types to types. The
3484 * default behavior of this class is to implement the identity
3485 * mapping (mapping a type to itself). This can be overridden in
3486 * subclasses.
3487 *
3488 * @param <S> the type of the second argument (the first being the
3489 * type itself) of this mapping; use Void if a second argument is
3490 * not needed.
3491 */
3492 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
3493 final public Type visit(Type t) { return t.accept(this, null); }
3494 public Type visitType(Type t, S s) { return t; }
3495 }
3496 // </editor-fold>
3497 }
