Mercurial > jdk8-mips64-public > langtools / file revision
src/share/classes/com/sun/tools/javac/code/Types.java@eff38cc97183
src/share/classes/com/sun/tools/javac/code/Types.java
Tue, 16 Sep 2008 18:35:18 -0700
- author
- jjg
- date
- Tue, 16 Sep 2008 18:35:18 -0700
- changeset 113
- eff38cc97183
- parent 110
- 91eea580fbe9
- child 121
- 609fb59657b4
- permissions
- -rw-r--r--
6574134: Allow for alternative implementation of Name Table with garbage collection of name bytes
Reviewed-by: darcy, mcimadamore
1 /*
2 * Copyright 2003-2008 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.util.*;
30 import com.sun.tools.javac.util.*;
31 import com.sun.tools.javac.util.List;
33 import com.sun.tools.javac.jvm.ClassReader;
34 import com.sun.tools.javac.comp.Check;
36 import static com.sun.tools.javac.code.Type.*;
37 import static com.sun.tools.javac.code.TypeTags.*;
38 import static com.sun.tools.javac.code.Symbol.*;
39 import static com.sun.tools.javac.code.Flags.*;
40 import static com.sun.tools.javac.code.BoundKind.*;
41 import static com.sun.tools.javac.util.ListBuffer.lb;
43 /**
44 * Utility class containing various operations on types.
45 *
46 * <p>Unless other names are more illustrative, the following naming
47 * conventions should be observed in this file:
48 *
49 * <dl>
50 * <dt>t</dt>
51 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
52 * <dt>s</dt>
53 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
54 * <dt>ts</dt>
55 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
56 * <dt>ss</dt>
57 * <dd>A second list of types should be named ss.</dd>
58 * </dl>
59 *
60 * <p><b>This is NOT part of any API supported by Sun Microsystems.
61 * If you write code that depends on this, you do so at your own risk.
62 * This code and its internal interfaces are subject to change or
63 * deletion without notice.</b>
64 */
65 public class Types {
66 protected static final Context.Key<Types> typesKey =
67 new Context.Key<Types>();
69 final Symtab syms;
70 final Names names;
71 final boolean allowBoxing;
72 final ClassReader reader;
73 final Source source;
74 final Check chk;
75 List<Warner> warnStack = List.nil();
76 final Name capturedName;
78 // <editor-fold defaultstate="collapsed" desc="Instantiating">
79 public static Types instance(Context context) {
80 Types instance = context.get(typesKey);
81 if (instance == null)
82 instance = new Types(context);
83 return instance;
84 }
86 protected Types(Context context) {
87 context.put(typesKey, this);
88 syms = Symtab.instance(context);
89 names = Names.instance(context);
90 allowBoxing = Source.instance(context).allowBoxing();
91 reader = ClassReader.instance(context);
92 source = Source.instance(context);
93 chk = Check.instance(context);
94 capturedName = names.fromString("<captured wildcard>");
95 }
96 // </editor-fold>
98 // <editor-fold defaultstate="collapsed" desc="upperBound">
99 /**
100 * The "rvalue conversion".<br>
101 * The upper bound of most types is the type
102 * itself. Wildcards, on the other hand have upper
103 * and lower bounds.
104 * @param t a type
105 * @return the upper bound of the given type
106 */
107 public Type upperBound(Type t) {
108 return upperBound.visit(t);
109 }
110 // where
111 private final MapVisitor<Void> upperBound = new MapVisitor<Void>() {
113 @Override
114 public Type visitWildcardType(WildcardType t, Void ignored) {
115 if (t.isSuperBound())
116 return t.bound == null ? syms.objectType : t.bound.bound;
117 else
118 return visit(t.type);
119 }
121 @Override
122 public Type visitCapturedType(CapturedType t, Void ignored) {
123 return visit(t.bound);
124 }
125 };
126 // </editor-fold>
128 // <editor-fold defaultstate="collapsed" desc="lowerBound">
129 /**
130 * The "lvalue conversion".<br>
131 * The lower bound of most types is the type
132 * itself. Wildcards, on the other hand have upper
133 * and lower bounds.
134 * @param t a type
135 * @return the lower bound of the given type
136 */
137 public Type lowerBound(Type t) {
138 return lowerBound.visit(t);
139 }
140 // where
141 private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() {
143 @Override
144 public Type visitWildcardType(WildcardType t, Void ignored) {
145 return t.isExtendsBound() ? syms.botType : visit(t.type);
146 }
148 @Override
149 public Type visitCapturedType(CapturedType t, Void ignored) {
150 return visit(t.getLowerBound());
151 }
152 };
153 // </editor-fold>
155 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
156 /**
157 * Checks that all the arguments to a class are unbounded
158 * wildcards or something else that doesn't make any restrictions
159 * on the arguments. If a class isUnbounded, a raw super- or
160 * subclass can be cast to it without a warning.
161 * @param t a type
162 * @return true iff the given type is unbounded or raw
163 */
164 public boolean isUnbounded(Type t) {
165 return isUnbounded.visit(t);
166 }
167 // where
168 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
170 public Boolean visitType(Type t, Void ignored) {
171 return true;
172 }
174 @Override
175 public Boolean visitClassType(ClassType t, Void ignored) {
176 List<Type> parms = t.tsym.type.allparams();
177 List<Type> args = t.allparams();
178 while (parms.nonEmpty()) {
179 WildcardType unb = new WildcardType(syms.objectType,
180 BoundKind.UNBOUND,
181 syms.boundClass,
182 (TypeVar)parms.head);
183 if (!containsType(args.head, unb))
184 return false;
185 parms = parms.tail;
186 args = args.tail;
187 }
188 return true;
189 }
190 };
191 // </editor-fold>
193 // <editor-fold defaultstate="collapsed" desc="asSub">
194 /**
195 * Return the least specific subtype of t that starts with symbol
196 * sym. If none exists, return null. The least specific subtype
197 * is determined as follows:
198 *
199 * <p>If there is exactly one parameterized instance of sym that is a
200 * subtype of t, that parameterized instance is returned.<br>
201 * Otherwise, if the plain type or raw type `sym' is a subtype of
202 * type t, the type `sym' itself is returned. Otherwise, null is
203 * returned.
204 */
205 public Type asSub(Type t, Symbol sym) {
206 return asSub.visit(t, sym);
207 }
208 // where
209 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
211 public Type visitType(Type t, Symbol sym) {
212 return null;
213 }
215 @Override
216 public Type visitClassType(ClassType t, Symbol sym) {
217 if (t.tsym == sym)
218 return t;
219 Type base = asSuper(sym.type, t.tsym);
220 if (base == null)
221 return null;
222 ListBuffer<Type> from = new ListBuffer<Type>();
223 ListBuffer<Type> to = new ListBuffer<Type>();
224 try {
225 adapt(base, t, from, to);
226 } catch (AdaptFailure ex) {
227 return null;
228 }
229 Type res = subst(sym.type, from.toList(), to.toList());
230 if (!isSubtype(res, t))
231 return null;
232 ListBuffer<Type> openVars = new ListBuffer<Type>();
233 for (List<Type> l = sym.type.allparams();
234 l.nonEmpty(); l = l.tail)
235 if (res.contains(l.head) && !t.contains(l.head))
236 openVars.append(l.head);
237 if (openVars.nonEmpty()) {
238 if (t.isRaw()) {
239 // The subtype of a raw type is raw
240 res = erasure(res);
241 } else {
242 // Unbound type arguments default to ?
243 List<Type> opens = openVars.toList();
244 ListBuffer<Type> qs = new ListBuffer<Type>();
245 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
246 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head));
247 }
248 res = subst(res, opens, qs.toList());
249 }
250 }
251 return res;
252 }
254 @Override
255 public Type visitErrorType(ErrorType t, Symbol sym) {
256 return t;
257 }
258 };
259 // </editor-fold>
261 // <editor-fold defaultstate="collapsed" desc="isConvertible">
262 /**
263 * Is t a subtype of or convertiable via boxing/unboxing
264 * convertions to s?
265 */
266 public boolean isConvertible(Type t, Type s, Warner warn) {
267 boolean tPrimitive = t.isPrimitive();
268 boolean sPrimitive = s.isPrimitive();
269 if (tPrimitive == sPrimitive)
270 return isSubtypeUnchecked(t, s, warn);
271 if (!allowBoxing) return false;
272 return tPrimitive
273 ? isSubtype(boxedClass(t).type, s)
274 : isSubtype(unboxedType(t), s);
275 }
277 /**
278 * Is t a subtype of or convertiable via boxing/unboxing
279 * convertions to s?
280 */
281 public boolean isConvertible(Type t, Type s) {
282 return isConvertible(t, s, Warner.noWarnings);
283 }
284 // </editor-fold>
286 // <editor-fold defaultstate="collapsed" desc="isSubtype">
287 /**
288 * Is t an unchecked subtype of s?
289 */
290 public boolean isSubtypeUnchecked(Type t, Type s) {
291 return isSubtypeUnchecked(t, s, Warner.noWarnings);
292 }
293 /**
294 * Is t an unchecked subtype of s?
295 */
296 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
297 if (t.tag == ARRAY && s.tag == ARRAY) {
298 return (((ArrayType)t).elemtype.tag <= lastBaseTag)
299 ? isSameType(elemtype(t), elemtype(s))
300 : isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
301 } else if (isSubtype(t, s)) {
302 return true;
303 }
304 else if (t.tag == TYPEVAR) {
305 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
306 }
307 else if (s.tag == UNDETVAR) {
308 UndetVar uv = (UndetVar)s;
309 if (uv.inst != null)
310 return isSubtypeUnchecked(t, uv.inst, warn);
311 }
312 else if (!s.isRaw()) {
313 Type t2 = asSuper(t, s.tsym);
314 if (t2 != null && t2.isRaw()) {
315 if (isReifiable(s))
316 warn.silentUnchecked();
317 else
318 warn.warnUnchecked();
319 return true;
320 }
321 }
322 return false;
323 }
325 /**
326 * Is t a subtype of s?<br>
327 * (not defined for Method and ForAll types)
328 */
329 final public boolean isSubtype(Type t, Type s) {
330 return isSubtype(t, s, true);
331 }
332 final public boolean isSubtypeNoCapture(Type t, Type s) {
333 return isSubtype(t, s, false);
334 }
335 public boolean isSubtype(Type t, Type s, boolean capture) {
336 if (t == s)
337 return true;
339 if (s.tag >= firstPartialTag)
340 return isSuperType(s, t);
342 Type lower = lowerBound(s);
343 if (s != lower)
344 return isSubtype(capture ? capture(t) : t, lower, false);
346 return isSubtype.visit(capture ? capture(t) : t, s);
347 }
348 // where
349 private TypeRelation isSubtype = new TypeRelation()
350 {
351 public Boolean visitType(Type t, Type s) {
352 switch (t.tag) {
353 case BYTE: case CHAR:
354 return (t.tag == s.tag ||
355 t.tag + 2 <= s.tag && s.tag <= DOUBLE);
356 case SHORT: case INT: case LONG: case FLOAT: case DOUBLE:
357 return t.tag <= s.tag && s.tag <= DOUBLE;
358 case BOOLEAN: case VOID:
359 return t.tag == s.tag;
360 case TYPEVAR:
361 return isSubtypeNoCapture(t.getUpperBound(), s);
362 case BOT:
363 return
364 s.tag == BOT || s.tag == CLASS ||
365 s.tag == ARRAY || s.tag == TYPEVAR;
366 case NONE:
367 return false;
368 default:
369 throw new AssertionError("isSubtype " + t.tag);
370 }
371 }
373 private Set<TypePair> cache = new HashSet<TypePair>();
375 private boolean containsTypeRecursive(Type t, Type s) {
376 TypePair pair = new TypePair(t, s);
377 if (cache.add(pair)) {
378 try {
379 return containsType(t.getTypeArguments(),
380 s.getTypeArguments());
381 } finally {
382 cache.remove(pair);
383 }
384 } else {
385 return containsType(t.getTypeArguments(),
386 rewriteSupers(s).getTypeArguments());
387 }
388 }
390 private Type rewriteSupers(Type t) {
391 if (!t.isParameterized())
392 return t;
393 ListBuffer<Type> from = lb();
394 ListBuffer<Type> to = lb();
395 adaptSelf(t, from, to);
396 if (from.isEmpty())
397 return t;
398 ListBuffer<Type> rewrite = lb();
399 boolean changed = false;
400 for (Type orig : to.toList()) {
401 Type s = rewriteSupers(orig);
402 if (s.isSuperBound() && !s.isExtendsBound()) {
403 s = new WildcardType(syms.objectType,
404 BoundKind.UNBOUND,
405 syms.boundClass);
406 changed = true;
407 } else if (s != orig) {
408 s = new WildcardType(upperBound(s),
409 BoundKind.EXTENDS,
410 syms.boundClass);
411 changed = true;
412 }
413 rewrite.append(s);
414 }
415 if (changed)
416 return subst(t.tsym.type, from.toList(), rewrite.toList());
417 else
418 return t;
419 }
421 @Override
422 public Boolean visitClassType(ClassType t, Type s) {
423 Type sup = asSuper(t, s.tsym);
424 return sup != null
425 && sup.tsym == s.tsym
426 // You're not allowed to write
427 // Vector<Object> vec = new Vector<String>();
428 // But with wildcards you can write
429 // Vector<? extends Object> vec = new Vector<String>();
430 // which means that subtype checking must be done
431 // here instead of same-type checking (via containsType).
432 && (!s.isParameterized() || containsTypeRecursive(s, sup))
433 && isSubtypeNoCapture(sup.getEnclosingType(),
434 s.getEnclosingType());
435 }
437 @Override
438 public Boolean visitArrayType(ArrayType t, Type s) {
439 if (s.tag == ARRAY) {
440 if (t.elemtype.tag <= lastBaseTag)
441 return isSameType(t.elemtype, elemtype(s));
442 else
443 return isSubtypeNoCapture(t.elemtype, elemtype(s));
444 }
446 if (s.tag == CLASS) {
447 Name sname = s.tsym.getQualifiedName();
448 return sname == names.java_lang_Object
449 || sname == names.java_lang_Cloneable
450 || sname == names.java_io_Serializable;
451 }
453 return false;
454 }
456 @Override
457 public Boolean visitUndetVar(UndetVar t, Type s) {
458 //todo: test against origin needed? or replace with substitution?
459 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
460 return true;
462 if (t.inst != null)
463 return isSubtypeNoCapture(t.inst, s); // TODO: ", warn"?
465 t.hibounds = t.hibounds.prepend(s);
466 return true;
467 }
469 @Override
470 public Boolean visitErrorType(ErrorType t, Type s) {
471 return true;
472 }
473 };
475 /**
476 * Is t a subtype of every type in given list `ts'?<br>
477 * (not defined for Method and ForAll types)<br>
478 * Allows unchecked conversions.
479 */
480 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
481 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
482 if (!isSubtypeUnchecked(t, l.head, warn))
483 return false;
484 return true;
485 }
487 /**
488 * Are corresponding elements of ts subtypes of ss? If lists are
489 * of different length, return false.
490 */
491 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
492 while (ts.tail != null && ss.tail != null
493 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
494 isSubtype(ts.head, ss.head)) {
495 ts = ts.tail;
496 ss = ss.tail;
497 }
498 return ts.tail == null && ss.tail == null;
499 /*inlined: ts.isEmpty() && ss.isEmpty();*/
500 }
502 /**
503 * Are corresponding elements of ts subtypes of ss, allowing
504 * unchecked conversions? If lists are of different length,
505 * return false.
506 **/
507 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
508 while (ts.tail != null && ss.tail != null
509 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
510 isSubtypeUnchecked(ts.head, ss.head, warn)) {
511 ts = ts.tail;
512 ss = ss.tail;
513 }
514 return ts.tail == null && ss.tail == null;
515 /*inlined: ts.isEmpty() && ss.isEmpty();*/
516 }
517 // </editor-fold>
519 // <editor-fold defaultstate="collapsed" desc="isSuperType">
520 /**
521 * Is t a supertype of s?
522 */
523 public boolean isSuperType(Type t, Type s) {
524 switch (t.tag) {
525 case ERROR:
526 return true;
527 case UNDETVAR: {
528 UndetVar undet = (UndetVar)t;
529 if (t == s ||
530 undet.qtype == s ||
531 s.tag == ERROR ||
532 s.tag == BOT) return true;
533 if (undet.inst != null)
534 return isSubtype(s, undet.inst);
535 undet.lobounds = undet.lobounds.prepend(s);
536 return true;
537 }
538 default:
539 return isSubtype(s, t);
540 }
541 }
542 // </editor-fold>
544 // <editor-fold defaultstate="collapsed" desc="isSameType">
545 /**
546 * Are corresponding elements of the lists the same type? If
547 * lists are of different length, return false.
548 */
549 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
550 while (ts.tail != null && ss.tail != null
551 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
552 isSameType(ts.head, ss.head)) {
553 ts = ts.tail;
554 ss = ss.tail;
555 }
556 return ts.tail == null && ss.tail == null;
557 /*inlined: ts.isEmpty() && ss.isEmpty();*/
558 }
560 /**
561 * Is t the same type as s?
562 */
563 public boolean isSameType(Type t, Type s) {
564 return isSameType.visit(t, s);
565 }
566 // where
567 private TypeRelation isSameType = new TypeRelation() {
569 public Boolean visitType(Type t, Type s) {
570 if (t == s)
571 return true;
573 if (s.tag >= firstPartialTag)
574 return visit(s, t);
576 switch (t.tag) {
577 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
578 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
579 return t.tag == s.tag;
580 case TYPEVAR:
581 return s.isSuperBound()
582 && !s.isExtendsBound()
583 && visit(t, upperBound(s));
584 default:
585 throw new AssertionError("isSameType " + t.tag);
586 }
587 }
589 @Override
590 public Boolean visitWildcardType(WildcardType t, Type s) {
591 if (s.tag >= firstPartialTag)
592 return visit(s, t);
593 else
594 return false;
595 }
597 @Override
598 public Boolean visitClassType(ClassType t, Type s) {
599 if (t == s)
600 return true;
602 if (s.tag >= firstPartialTag)
603 return visit(s, t);
605 if (s.isSuperBound() && !s.isExtendsBound())
606 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
608 if (t.isCompound() && s.isCompound()) {
609 if (!visit(supertype(t), supertype(s)))
610 return false;
612 HashSet<SingletonType> set = new HashSet<SingletonType>();
613 for (Type x : interfaces(t))
614 set.add(new SingletonType(x));
615 for (Type x : interfaces(s)) {
616 if (!set.remove(new SingletonType(x)))
617 return false;
618 }
619 return (set.size() == 0);
620 }
621 return t.tsym == s.tsym
622 && visit(t.getEnclosingType(), s.getEnclosingType())
623 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
624 }
626 @Override
627 public Boolean visitArrayType(ArrayType t, Type s) {
628 if (t == s)
629 return true;
631 if (s.tag >= firstPartialTag)
632 return visit(s, t);
634 return s.tag == ARRAY
635 && containsTypeEquivalent(t.elemtype, elemtype(s));
636 }
638 @Override
639 public Boolean visitMethodType(MethodType t, Type s) {
640 // isSameType for methods does not take thrown
641 // exceptions into account!
642 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
643 }
645 @Override
646 public Boolean visitPackageType(PackageType t, Type s) {
647 return t == s;
648 }
650 @Override
651 public Boolean visitForAll(ForAll t, Type s) {
652 if (s.tag != FORALL)
653 return false;
655 ForAll forAll = (ForAll)s;
656 return hasSameBounds(t, forAll)
657 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
658 }
660 @Override
661 public Boolean visitUndetVar(UndetVar t, Type s) {
662 if (s.tag == WILDCARD)
663 // FIXME, this might be leftovers from before capture conversion
664 return false;
666 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
667 return true;
669 if (t.inst != null)
670 return visit(t.inst, s);
672 t.inst = fromUnknownFun.apply(s);
673 for (List<Type> l = t.lobounds; l.nonEmpty(); l = l.tail) {
674 if (!isSubtype(l.head, t.inst))
675 return false;
676 }
677 for (List<Type> l = t.hibounds; l.nonEmpty(); l = l.tail) {
678 if (!isSubtype(t.inst, l.head))
679 return false;
680 }
681 return true;
682 }
684 @Override
685 public Boolean visitErrorType(ErrorType t, Type s) {
686 return true;
687 }
688 };
689 // </editor-fold>
691 // <editor-fold defaultstate="collapsed" desc="fromUnknownFun">
692 /**
693 * A mapping that turns all unknown types in this type to fresh
694 * unknown variables.
695 */
696 public Mapping fromUnknownFun = new Mapping("fromUnknownFun") {
697 public Type apply(Type t) {
698 if (t.tag == UNKNOWN) return new UndetVar(t);
699 else return t.map(this);
700 }
701 };
702 // </editor-fold>
704 // <editor-fold defaultstate="collapsed" desc="Contains Type">
705 public boolean containedBy(Type t, Type s) {
706 switch (t.tag) {
707 case UNDETVAR:
708 if (s.tag == WILDCARD) {
709 UndetVar undetvar = (UndetVar)t;
711 // Because of wildcard capture, s must be on the left
712 // hand side of an assignment. Furthermore, t is an
713 // underconstrained type variable, for example, one
714 // that is only used in the return type of a method.
715 // If the type variable is truly underconstrained, it
716 // cannot have any low bounds:
717 assert undetvar.lobounds.isEmpty() : undetvar;
719 undetvar.inst = glb(upperBound(s), undetvar.inst);
720 return true;
721 } else {
722 return isSameType(t, s);
723 }
724 case ERROR:
725 return true;
726 default:
727 return containsType(s, t);
728 }
729 }
731 boolean containsType(List<Type> ts, List<Type> ss) {
732 while (ts.nonEmpty() && ss.nonEmpty()
733 && containsType(ts.head, ss.head)) {
734 ts = ts.tail;
735 ss = ss.tail;
736 }
737 return ts.isEmpty() && ss.isEmpty();
738 }
740 /**
741 * Check if t contains s.
742 *
743 * <p>T contains S if:
744 *
745 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
746 *
747 * <p>This relation is only used by ClassType.isSubtype(), that
748 * is,
749 *
750 * <p>{@code C<S> <: C<T> if T contains S.}
751 *
752 * <p>Because of F-bounds, this relation can lead to infinite
753 * recursion. Thus we must somehow break that recursion. Notice
754 * that containsType() is only called from ClassType.isSubtype().
755 * Since the arguments have already been checked against their
756 * bounds, we know:
757 *
758 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
759 *
760 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
761 *
762 * @param t a type
763 * @param s a type
764 */
765 public boolean containsType(Type t, Type s) {
766 return containsType.visit(t, s);
767 }
768 // where
769 private TypeRelation containsType = new TypeRelation() {
771 private Type U(Type t) {
772 while (t.tag == WILDCARD) {
773 WildcardType w = (WildcardType)t;
774 if (w.isSuperBound())
775 return w.bound == null ? syms.objectType : w.bound.bound;
776 else
777 t = w.type;
778 }
779 return t;
780 }
782 private Type L(Type t) {
783 while (t.tag == WILDCARD) {
784 WildcardType w = (WildcardType)t;
785 if (w.isExtendsBound())
786 return syms.botType;
787 else
788 t = w.type;
789 }
790 return t;
791 }
793 public Boolean visitType(Type t, Type s) {
794 if (s.tag >= firstPartialTag)
795 return containedBy(s, t);
796 else
797 return isSameType(t, s);
798 }
800 void debugContainsType(WildcardType t, Type s) {
801 System.err.println();
802 System.err.format(" does %s contain %s?%n", t, s);
803 System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
804 upperBound(s), s, t, U(t),
805 t.isSuperBound()
806 || isSubtypeNoCapture(upperBound(s), U(t)));
807 System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
808 L(t), t, s, lowerBound(s),
809 t.isExtendsBound()
810 || isSubtypeNoCapture(L(t), lowerBound(s)));
811 System.err.println();
812 }
814 @Override
815 public Boolean visitWildcardType(WildcardType t, Type s) {
816 if (s.tag >= firstPartialTag)
817 return containedBy(s, t);
818 else {
819 // debugContainsType(t, s);
820 return isSameWildcard(t, s)
821 || isCaptureOf(s, t)
822 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
823 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
824 }
825 }
827 @Override
828 public Boolean visitUndetVar(UndetVar t, Type s) {
829 if (s.tag != WILDCARD)
830 return isSameType(t, s);
831 else
832 return false;
833 }
835 @Override
836 public Boolean visitErrorType(ErrorType t, Type s) {
837 return true;
838 }
839 };
841 public boolean isCaptureOf(Type s, WildcardType t) {
842 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
843 return false;
844 return isSameWildcard(t, ((CapturedType)s).wildcard);
845 }
847 public boolean isSameWildcard(WildcardType t, Type s) {
848 if (s.tag != WILDCARD)
849 return false;
850 WildcardType w = (WildcardType)s;
851 return w.kind == t.kind && w.type == t.type;
852 }
854 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
855 while (ts.nonEmpty() && ss.nonEmpty()
856 && containsTypeEquivalent(ts.head, ss.head)) {
857 ts = ts.tail;
858 ss = ss.tail;
859 }
860 return ts.isEmpty() && ss.isEmpty();
861 }
862 // </editor-fold>
864 // <editor-fold defaultstate="collapsed" desc="isCastable">
865 public boolean isCastable(Type t, Type s) {
866 return isCastable(t, s, Warner.noWarnings);
867 }
869 /**
870 * Is t is castable to s?<br>
871 * s is assumed to be an erased type.<br>
872 * (not defined for Method and ForAll types).
873 */
874 public boolean isCastable(Type t, Type s, Warner warn) {
875 if (t == s)
876 return true;
878 if (t.isPrimitive() != s.isPrimitive())
879 return allowBoxing && isConvertible(t, s, warn);
881 if (warn != warnStack.head) {
882 try {
883 warnStack = warnStack.prepend(warn);
884 return isCastable.visit(t, s);
885 } finally {
886 warnStack = warnStack.tail;
887 }
888 } else {
889 return isCastable.visit(t, s);
890 }
891 }
892 // where
893 private TypeRelation isCastable = new TypeRelation() {
895 public Boolean visitType(Type t, Type s) {
896 if (s.tag == ERROR)
897 return true;
899 switch (t.tag) {
900 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
901 case DOUBLE:
902 return s.tag <= DOUBLE;
903 case BOOLEAN:
904 return s.tag == BOOLEAN;
905 case VOID:
906 return false;
907 case BOT:
908 return isSubtype(t, s);
909 default:
910 throw new AssertionError();
911 }
912 }
914 @Override
915 public Boolean visitWildcardType(WildcardType t, Type s) {
916 return isCastable(upperBound(t), s, warnStack.head);
917 }
919 @Override
920 public Boolean visitClassType(ClassType t, Type s) {
921 if (s.tag == ERROR || s.tag == BOT)
922 return true;
924 if (s.tag == TYPEVAR) {
925 if (isCastable(s.getUpperBound(), t, Warner.noWarnings)) {
926 warnStack.head.warnUnchecked();
927 return true;
928 } else {
929 return false;
930 }
931 }
933 if (t.isCompound()) {
934 if (!visit(supertype(t), s))
935 return false;
936 for (Type intf : interfaces(t)) {
937 if (!visit(intf, s))
938 return false;
939 }
940 return true;
941 }
943 if (s.isCompound()) {
944 // call recursively to reuse the above code
945 return visitClassType((ClassType)s, t);
946 }
948 if (s.tag == CLASS || s.tag == ARRAY) {
949 boolean upcast;
950 if ((upcast = isSubtype(erasure(t), erasure(s)))
951 || isSubtype(erasure(s), erasure(t))) {
952 if (!upcast && s.tag == ARRAY) {
953 if (!isReifiable(s))
954 warnStack.head.warnUnchecked();
955 return true;
956 } else if (s.isRaw()) {
957 return true;
958 } else if (t.isRaw()) {
959 if (!isUnbounded(s))
960 warnStack.head.warnUnchecked();
961 return true;
962 }
963 // Assume |a| <: |b|
964 final Type a = upcast ? t : s;
965 final Type b = upcast ? s : t;
966 final boolean HIGH = true;
967 final boolean LOW = false;
968 final boolean DONT_REWRITE_TYPEVARS = false;
969 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
970 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
971 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
972 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
973 Type lowSub = asSub(bLow, aLow.tsym);
974 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
975 if (highSub == null) {
976 final boolean REWRITE_TYPEVARS = true;
977 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
978 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
979 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
980 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
981 lowSub = asSub(bLow, aLow.tsym);
982 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
983 }
984 if (highSub != null) {
985 assert a.tsym == highSub.tsym && a.tsym == lowSub.tsym
986 : a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym;
987 if (!disjointTypes(aHigh.getTypeArguments(), highSub.getTypeArguments())
988 && !disjointTypes(aHigh.getTypeArguments(), lowSub.getTypeArguments())
989 && !disjointTypes(aLow.getTypeArguments(), highSub.getTypeArguments())
990 && !disjointTypes(aLow.getTypeArguments(), lowSub.getTypeArguments())) {
991 if (upcast ? giveWarning(a, highSub) || giveWarning(a, lowSub)
992 : giveWarning(highSub, a) || giveWarning(lowSub, a))
993 warnStack.head.warnUnchecked();
994 return true;
995 }
996 }
997 if (isReifiable(s))
998 return isSubtypeUnchecked(a, b);
999 else
1000 return isSubtypeUnchecked(a, b, warnStack.head);
1001 }
1003 // Sidecast
1004 if (s.tag == CLASS) {
1005 if ((s.tsym.flags() & INTERFACE) != 0) {
1006 return ((t.tsym.flags() & FINAL) == 0)
1007 ? sideCast(t, s, warnStack.head)
1008 : sideCastFinal(t, s, warnStack.head);
1009 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1010 return ((s.tsym.flags() & FINAL) == 0)
1011 ? sideCast(t, s, warnStack.head)
1012 : sideCastFinal(t, s, warnStack.head);
1013 } else {
1014 // unrelated class types
1015 return false;
1016 }
1017 }
1018 }
1019 return false;
1020 }
1022 @Override
1023 public Boolean visitArrayType(ArrayType t, Type s) {
1024 switch (s.tag) {
1025 case ERROR:
1026 case BOT:
1027 return true;
1028 case TYPEVAR:
1029 if (isCastable(s, t, Warner.noWarnings)) {
1030 warnStack.head.warnUnchecked();
1031 return true;
1032 } else {
1033 return false;
1034 }
1035 case CLASS:
1036 return isSubtype(t, s);
1037 case ARRAY:
1038 if (elemtype(t).tag <= lastBaseTag) {
1039 return elemtype(t).tag == elemtype(s).tag;
1040 } else {
1041 return visit(elemtype(t), elemtype(s));
1042 }
1043 default:
1044 return false;
1045 }
1046 }
1048 @Override
1049 public Boolean visitTypeVar(TypeVar t, Type s) {
1050 switch (s.tag) {
1051 case ERROR:
1052 case BOT:
1053 return true;
1054 case TYPEVAR:
1055 if (isSubtype(t, s)) {
1056 return true;
1057 } else if (isCastable(t.bound, s, Warner.noWarnings)) {
1058 warnStack.head.warnUnchecked();
1059 return true;
1060 } else {
1061 return false;
1062 }
1063 default:
1064 return isCastable(t.bound, s, warnStack.head);
1065 }
1066 }
1068 @Override
1069 public Boolean visitErrorType(ErrorType t, Type s) {
1070 return true;
1071 }
1072 };
1073 // </editor-fold>
1075 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1076 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1077 while (ts.tail != null && ss.tail != null) {
1078 if (disjointType(ts.head, ss.head)) return true;
1079 ts = ts.tail;
1080 ss = ss.tail;
1081 }
1082 return false;
1083 }
1085 /**
1086 * Two types or wildcards are considered disjoint if it can be
1087 * proven that no type can be contained in both. It is
1088 * conservative in that it is allowed to say that two types are
1089 * not disjoint, even though they actually are.
1090 *
1091 * The type C<X> is castable to C<Y> exactly if X and Y are not
1092 * disjoint.
1093 */
1094 public boolean disjointType(Type t, Type s) {
1095 return disjointType.visit(t, s);
1096 }
1097 // where
1098 private TypeRelation disjointType = new TypeRelation() {
1100 private Set<TypePair> cache = new HashSet<TypePair>();
1102 public Boolean visitType(Type t, Type s) {
1103 if (s.tag == WILDCARD)
1104 return visit(s, t);
1105 else
1106 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1107 }
1109 private boolean isCastableRecursive(Type t, Type s) {
1110 TypePair pair = new TypePair(t, s);
1111 if (cache.add(pair)) {
1112 try {
1113 return Types.this.isCastable(t, s);
1114 } finally {
1115 cache.remove(pair);
1116 }
1117 } else {
1118 return true;
1119 }
1120 }
1122 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1123 TypePair pair = new TypePair(t, s);
1124 if (cache.add(pair)) {
1125 try {
1126 return Types.this.notSoftSubtype(t, s);
1127 } finally {
1128 cache.remove(pair);
1129 }
1130 } else {
1131 return false;
1132 }
1133 }
1135 @Override
1136 public Boolean visitWildcardType(WildcardType t, Type s) {
1137 if (t.isUnbound())
1138 return false;
1140 if (s.tag != WILDCARD) {
1141 if (t.isExtendsBound())
1142 return notSoftSubtypeRecursive(s, t.type);
1143 else // isSuperBound()
1144 return notSoftSubtypeRecursive(t.type, s);
1145 }
1147 if (s.isUnbound())
1148 return false;
1150 if (t.isExtendsBound()) {
1151 if (s.isExtendsBound())
1152 return !isCastableRecursive(t.type, upperBound(s));
1153 else if (s.isSuperBound())
1154 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1155 } else if (t.isSuperBound()) {
1156 if (s.isExtendsBound())
1157 return notSoftSubtypeRecursive(t.type, upperBound(s));
1158 }
1159 return false;
1160 }
1161 };
1162 // </editor-fold>
1164 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1165 /**
1166 * Returns the lower bounds of the formals of a method.
1167 */
1168 public List<Type> lowerBoundArgtypes(Type t) {
1169 return map(t.getParameterTypes(), lowerBoundMapping);
1170 }
1171 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1172 public Type apply(Type t) {
1173 return lowerBound(t);
1174 }
1175 };
1176 // </editor-fold>
1178 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1179 /**
1180 * This relation answers the question: is impossible that
1181 * something of type `t' can be a subtype of `s'? This is
1182 * different from the question "is `t' not a subtype of `s'?"
1183 * when type variables are involved: Integer is not a subtype of T
1184 * where <T extends Number> but it is not true that Integer cannot
1185 * possibly be a subtype of T.
1186 */
1187 public boolean notSoftSubtype(Type t, Type s) {
1188 if (t == s) return false;
1189 if (t.tag == TYPEVAR) {
1190 TypeVar tv = (TypeVar) t;
1191 if (s.tag == TYPEVAR)
1192 s = s.getUpperBound();
1193 return !isCastable(tv.bound,
1194 s,
1195 Warner.noWarnings);
1196 }
1197 if (s.tag != WILDCARD)
1198 s = upperBound(s);
1199 if (s.tag == TYPEVAR)
1200 s = s.getUpperBound();
1201 return !isSubtype(t, s);
1202 }
1203 // </editor-fold>
1205 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1206 public boolean isReifiable(Type t) {
1207 return isReifiable.visit(t);
1208 }
1209 // where
1210 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1212 public Boolean visitType(Type t, Void ignored) {
1213 return true;
1214 }
1216 @Override
1217 public Boolean visitClassType(ClassType t, Void ignored) {
1218 if (!t.isParameterized())
1219 return true;
1221 for (Type param : t.allparams()) {
1222 if (!param.isUnbound())
1223 return false;
1224 }
1225 return true;
1226 }
1228 @Override
1229 public Boolean visitArrayType(ArrayType t, Void ignored) {
1230 return visit(t.elemtype);
1231 }
1233 @Override
1234 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1235 return false;
1236 }
1237 };
1238 // </editor-fold>
1240 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1241 public boolean isArray(Type t) {
1242 while (t.tag == WILDCARD)
1243 t = upperBound(t);
1244 return t.tag == ARRAY;
1245 }
1247 /**
1248 * The element type of an array.
1249 */
1250 public Type elemtype(Type t) {
1251 switch (t.tag) {
1252 case WILDCARD:
1253 return elemtype(upperBound(t));
1254 case ARRAY:
1255 return ((ArrayType)t).elemtype;
1256 case FORALL:
1257 return elemtype(((ForAll)t).qtype);
1258 case ERROR:
1259 return t;
1260 default:
1261 return null;
1262 }
1263 }
1265 /**
1266 * Mapping to take element type of an arraytype
1267 */
1268 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1269 public Type apply(Type t) { return elemtype(t); }
1270 };
1272 /**
1273 * The number of dimensions of an array type.
1274 */
1275 public int dimensions(Type t) {
1276 int result = 0;
1277 while (t.tag == ARRAY) {
1278 result++;
1279 t = elemtype(t);
1280 }
1281 return result;
1282 }
1283 // </editor-fold>
1285 // <editor-fold defaultstate="collapsed" desc="asSuper">
1286 /**
1287 * Return the (most specific) base type of t that starts with the
1288 * given symbol. If none exists, return null.
1289 *
1290 * @param t a type
1291 * @param sym a symbol
1292 */
1293 public Type asSuper(Type t, Symbol sym) {
1294 return asSuper.visit(t, sym);
1295 }
1296 // where
1297 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1299 public Type visitType(Type t, Symbol sym) {
1300 return null;
1301 }
1303 @Override
1304 public Type visitClassType(ClassType t, Symbol sym) {
1305 if (t.tsym == sym)
1306 return t;
1308 Type st = supertype(t);
1309 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1310 Type x = asSuper(st, sym);
1311 if (x != null)
1312 return x;
1313 }
1314 if ((sym.flags() & INTERFACE) != 0) {
1315 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1316 Type x = asSuper(l.head, sym);
1317 if (x != null)
1318 return x;
1319 }
1320 }
1321 return null;
1322 }
1324 @Override
1325 public Type visitArrayType(ArrayType t, Symbol sym) {
1326 return isSubtype(t, sym.type) ? sym.type : null;
1327 }
1329 @Override
1330 public Type visitTypeVar(TypeVar t, Symbol sym) {
1331 if (t.tsym == sym)
1332 return t;
1333 else
1334 return asSuper(t.bound, sym);
1335 }
1337 @Override
1338 public Type visitErrorType(ErrorType t, Symbol sym) {
1339 return t;
1340 }
1341 };
1343 /**
1344 * Return the base type of t or any of its outer types that starts
1345 * with the given symbol. If none exists, return null.
1346 *
1347 * @param t a type
1348 * @param sym a symbol
1349 */
1350 public Type asOuterSuper(Type t, Symbol sym) {
1351 switch (t.tag) {
1352 case CLASS:
1353 do {
1354 Type s = asSuper(t, sym);
1355 if (s != null) return s;
1356 t = t.getEnclosingType();
1357 } while (t.tag == CLASS);
1358 return null;
1359 case ARRAY:
1360 return isSubtype(t, sym.type) ? sym.type : null;
1361 case TYPEVAR:
1362 return asSuper(t, sym);
1363 case ERROR:
1364 return t;
1365 default:
1366 return null;
1367 }
1368 }
1370 /**
1371 * Return the base type of t or any of its enclosing types that
1372 * starts with the given symbol. If none exists, return null.
1373 *
1374 * @param t a type
1375 * @param sym a symbol
1376 */
1377 public Type asEnclosingSuper(Type t, Symbol sym) {
1378 switch (t.tag) {
1379 case CLASS:
1380 do {
1381 Type s = asSuper(t, sym);
1382 if (s != null) return s;
1383 Type outer = t.getEnclosingType();
1384 t = (outer.tag == CLASS) ? outer :
1385 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1386 Type.noType;
1387 } while (t.tag == CLASS);
1388 return null;
1389 case ARRAY:
1390 return isSubtype(t, sym.type) ? sym.type : null;
1391 case TYPEVAR:
1392 return asSuper(t, sym);
1393 case ERROR:
1394 return t;
1395 default:
1396 return null;
1397 }
1398 }
1399 // </editor-fold>
1401 // <editor-fold defaultstate="collapsed" desc="memberType">
1402 /**
1403 * The type of given symbol, seen as a member of t.
1404 *
1405 * @param t a type
1406 * @param sym a symbol
1407 */
1408 public Type memberType(Type t, Symbol sym) {
1409 return (sym.flags() & STATIC) != 0
1410 ? sym.type
1411 : memberType.visit(t, sym);
1412 }
1413 // where
1414 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1416 public Type visitType(Type t, Symbol sym) {
1417 return sym.type;
1418 }
1420 @Override
1421 public Type visitWildcardType(WildcardType t, Symbol sym) {
1422 return memberType(upperBound(t), sym);
1423 }
1425 @Override
1426 public Type visitClassType(ClassType t, Symbol sym) {
1427 Symbol owner = sym.owner;
1428 long flags = sym.flags();
1429 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1430 Type base = asOuterSuper(t, owner);
1431 if (base != null) {
1432 List<Type> ownerParams = owner.type.allparams();
1433 List<Type> baseParams = base.allparams();
1434 if (ownerParams.nonEmpty()) {
1435 if (baseParams.isEmpty()) {
1436 // then base is a raw type
1437 return erasure(sym.type);
1438 } else {
1439 return subst(sym.type, ownerParams, baseParams);
1440 }
1441 }
1442 }
1443 }
1444 return sym.type;
1445 }
1447 @Override
1448 public Type visitTypeVar(TypeVar t, Symbol sym) {
1449 return memberType(t.bound, sym);
1450 }
1452 @Override
1453 public Type visitErrorType(ErrorType t, Symbol sym) {
1454 return t;
1455 }
1456 };
1457 // </editor-fold>
1459 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1460 public boolean isAssignable(Type t, Type s) {
1461 return isAssignable(t, s, Warner.noWarnings);
1462 }
1464 /**
1465 * Is t assignable to s?<br>
1466 * Equivalent to subtype except for constant values and raw
1467 * types.<br>
1468 * (not defined for Method and ForAll types)
1469 */
1470 public boolean isAssignable(Type t, Type s, Warner warn) {
1471 if (t.tag == ERROR)
1472 return true;
1473 if (t.tag <= INT && t.constValue() != null) {
1474 int value = ((Number)t.constValue()).intValue();
1475 switch (s.tag) {
1476 case BYTE:
1477 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1478 return true;
1479 break;
1480 case CHAR:
1481 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1482 return true;
1483 break;
1484 case SHORT:
1485 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1486 return true;
1487 break;
1488 case INT:
1489 return true;
1490 case CLASS:
1491 switch (unboxedType(s).tag) {
1492 case BYTE:
1493 case CHAR:
1494 case SHORT:
1495 return isAssignable(t, unboxedType(s), warn);
1496 }
1497 break;
1498 }
1499 }
1500 return isConvertible(t, s, warn);
1501 }
1502 // </editor-fold>
1504 // <editor-fold defaultstate="collapsed" desc="erasure">
1505 /**
1506 * The erasure of t {@code |t|} -- the type that results when all
1507 * type parameters in t are deleted.
1508 */
1509 public Type erasure(Type t) {
1510 return erasure(t, false);
1511 }
1512 //where
1513 private Type erasure(Type t, boolean recurse) {
1514 if (t.tag <= lastBaseTag)
1515 return t; /* fast special case */
1516 else
1517 return erasure.visit(t, recurse);
1518 }
1519 // where
1520 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
1521 public Type visitType(Type t, Boolean recurse) {
1522 if (t.tag <= lastBaseTag)
1523 return t; /*fast special case*/
1524 else
1525 return t.map(recurse ? erasureRecFun : erasureFun);
1526 }
1528 @Override
1529 public Type visitWildcardType(WildcardType t, Boolean recurse) {
1530 return erasure(upperBound(t), recurse);
1531 }
1533 @Override
1534 public Type visitClassType(ClassType t, Boolean recurse) {
1535 Type erased = t.tsym.erasure(Types.this);
1536 if (recurse) {
1537 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
1538 }
1539 return erased;
1540 }
1542 @Override
1543 public Type visitTypeVar(TypeVar t, Boolean recurse) {
1544 return erasure(t.bound, recurse);
1545 }
1547 @Override
1548 public Type visitErrorType(ErrorType t, Boolean recurse) {
1549 return t;
1550 }
1551 };
1553 private Mapping erasureFun = new Mapping ("erasure") {
1554 public Type apply(Type t) { return erasure(t); }
1555 };
1557 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
1558 public Type apply(Type t) { return erasureRecursive(t); }
1559 };
1561 public List<Type> erasure(List<Type> ts) {
1562 return Type.map(ts, erasureFun);
1563 }
1565 public Type erasureRecursive(Type t) {
1566 return erasure(t, true);
1567 }
1569 public List<Type> erasureRecursive(List<Type> ts) {
1570 return Type.map(ts, erasureRecFun);
1571 }
1572 // </editor-fold>
1574 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
1575 /**
1576 * Make a compound type from non-empty list of types
1577 *
1578 * @param bounds the types from which the compound type is formed
1579 * @param supertype is objectType if all bounds are interfaces,
1580 * null otherwise.
1581 */
1582 public Type makeCompoundType(List<Type> bounds,
1583 Type supertype) {
1584 ClassSymbol bc =
1585 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
1586 Type.moreInfo
1587 ? names.fromString(bounds.toString())
1588 : names.empty,
1589 syms.noSymbol);
1590 if (bounds.head.tag == TYPEVAR)
1591 // error condition, recover
1592 bc.erasure_field = syms.objectType;
1593 else
1594 bc.erasure_field = erasure(bounds.head);
1595 bc.members_field = new Scope(bc);
1596 ClassType bt = (ClassType)bc.type;
1597 bt.allparams_field = List.nil();
1598 if (supertype != null) {
1599 bt.supertype_field = supertype;
1600 bt.interfaces_field = bounds;
1601 } else {
1602 bt.supertype_field = bounds.head;
1603 bt.interfaces_field = bounds.tail;
1604 }
1605 assert bt.supertype_field.tsym.completer != null
1606 || !bt.supertype_field.isInterface()
1607 : bt.supertype_field;
1608 return bt;
1609 }
1611 /**
1612 * Same as {@link #makeCompoundType(List,Type)}, except that the
1613 * second parameter is computed directly. Note that this might
1614 * cause a symbol completion. Hence, this version of
1615 * makeCompoundType may not be called during a classfile read.
1616 */
1617 public Type makeCompoundType(List<Type> bounds) {
1618 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1619 supertype(bounds.head) : null;
1620 return makeCompoundType(bounds, supertype);
1621 }
1623 /**
1624 * A convenience wrapper for {@link #makeCompoundType(List)}; the
1625 * arguments are converted to a list and passed to the other
1626 * method. Note that this might cause a symbol completion.
1627 * Hence, this version of makeCompoundType may not be called
1628 * during a classfile read.
1629 */
1630 public Type makeCompoundType(Type bound1, Type bound2) {
1631 return makeCompoundType(List.of(bound1, bound2));
1632 }
1633 // </editor-fold>
1635 // <editor-fold defaultstate="collapsed" desc="supertype">
1636 public Type supertype(Type t) {
1637 return supertype.visit(t);
1638 }
1639 // where
1640 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
1642 public Type visitType(Type t, Void ignored) {
1643 // A note on wildcards: there is no good way to
1644 // determine a supertype for a super bounded wildcard.
1645 return null;
1646 }
1648 @Override
1649 public Type visitClassType(ClassType t, Void ignored) {
1650 if (t.supertype_field == null) {
1651 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
1652 // An interface has no superclass; its supertype is Object.
1653 if (t.isInterface())
1654 supertype = ((ClassType)t.tsym.type).supertype_field;
1655 if (t.supertype_field == null) {
1656 List<Type> actuals = classBound(t).allparams();
1657 List<Type> formals = t.tsym.type.allparams();
1658 if (t.hasErasedSupertypes()) {
1659 t.supertype_field = erasureRecursive(supertype);
1660 } else if (formals.nonEmpty()) {
1661 t.supertype_field = subst(supertype, formals, actuals);
1662 }
1663 else {
1664 t.supertype_field = supertype;
1665 }
1666 }
1667 }
1668 return t.supertype_field;
1669 }
1671 /**
1672 * The supertype is always a class type. If the type
1673 * variable's bounds start with a class type, this is also
1674 * the supertype. Otherwise, the supertype is
1675 * java.lang.Object.
1676 */
1677 @Override
1678 public Type visitTypeVar(TypeVar t, Void ignored) {
1679 if (t.bound.tag == TYPEVAR ||
1680 (!t.bound.isCompound() && !t.bound.isInterface())) {
1681 return t.bound;
1682 } else {
1683 return supertype(t.bound);
1684 }
1685 }
1687 @Override
1688 public Type visitArrayType(ArrayType t, Void ignored) {
1689 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
1690 return arraySuperType();
1691 else
1692 return new ArrayType(supertype(t.elemtype), t.tsym);
1693 }
1695 @Override
1696 public Type visitErrorType(ErrorType t, Void ignored) {
1697 return t;
1698 }
1699 };
1700 // </editor-fold>
1702 // <editor-fold defaultstate="collapsed" desc="interfaces">
1703 /**
1704 * Return the interfaces implemented by this class.
1705 */
1706 public List<Type> interfaces(Type t) {
1707 return interfaces.visit(t);
1708 }
1709 // where
1710 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
1712 public List<Type> visitType(Type t, Void ignored) {
1713 return List.nil();
1714 }
1716 @Override
1717 public List<Type> visitClassType(ClassType t, Void ignored) {
1718 if (t.interfaces_field == null) {
1719 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
1720 if (t.interfaces_field == null) {
1721 // If t.interfaces_field is null, then t must
1722 // be a parameterized type (not to be confused
1723 // with a generic type declaration).
1724 // Terminology:
1725 // Parameterized type: List<String>
1726 // Generic type declaration: class List<E> { ... }
1727 // So t corresponds to List<String> and
1728 // t.tsym.type corresponds to List<E>.
1729 // The reason t must be parameterized type is
1730 // that completion will happen as a side
1731 // effect of calling
1732 // ClassSymbol.getInterfaces. Since
1733 // t.interfaces_field is null after
1734 // completion, we can assume that t is not the
1735 // type of a class/interface declaration.
1736 assert t != t.tsym.type : t.toString();
1737 List<Type> actuals = t.allparams();
1738 List<Type> formals = t.tsym.type.allparams();
1739 if (t.hasErasedSupertypes()) {
1740 t.interfaces_field = erasureRecursive(interfaces);
1741 } else if (formals.nonEmpty()) {
1742 t.interfaces_field =
1743 upperBounds(subst(interfaces, formals, actuals));
1744 }
1745 else {
1746 t.interfaces_field = interfaces;
1747 }
1748 }
1749 }
1750 return t.interfaces_field;
1751 }
1753 @Override
1754 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
1755 if (t.bound.isCompound())
1756 return interfaces(t.bound);
1758 if (t.bound.isInterface())
1759 return List.of(t.bound);
1761 return List.nil();
1762 }
1763 };
1764 // </editor-fold>
1766 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
1767 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
1769 public boolean isDerivedRaw(Type t) {
1770 Boolean result = isDerivedRawCache.get(t);
1771 if (result == null) {
1772 result = isDerivedRawInternal(t);
1773 isDerivedRawCache.put(t, result);
1774 }
1775 return result;
1776 }
1778 public boolean isDerivedRawInternal(Type t) {
1779 if (t.isErroneous())
1780 return false;
1781 return
1782 t.isRaw() ||
1783 supertype(t) != null && isDerivedRaw(supertype(t)) ||
1784 isDerivedRaw(interfaces(t));
1785 }
1787 public boolean isDerivedRaw(List<Type> ts) {
1788 List<Type> l = ts;
1789 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
1790 return l.nonEmpty();
1791 }
1792 // </editor-fold>
1794 // <editor-fold defaultstate="collapsed" desc="setBounds">
1795 /**
1796 * Set the bounds field of the given type variable to reflect a
1797 * (possibly multiple) list of bounds.
1798 * @param t a type variable
1799 * @param bounds the bounds, must be nonempty
1800 * @param supertype is objectType if all bounds are interfaces,
1801 * null otherwise.
1802 */
1803 public void setBounds(TypeVar t, List<Type> bounds, Type supertype) {
1804 if (bounds.tail.isEmpty())
1805 t.bound = bounds.head;
1806 else
1807 t.bound = makeCompoundType(bounds, supertype);
1808 t.rank_field = -1;
1809 }
1811 /**
1812 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
1813 * third parameter is computed directly. Note that this test
1814 * might cause a symbol completion. Hence, this version of
1815 * setBounds may not be called during a classfile read.
1816 */
1817 public void setBounds(TypeVar t, List<Type> bounds) {
1818 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1819 supertype(bounds.head) : null;
1820 setBounds(t, bounds, supertype);
1821 t.rank_field = -1;
1822 }
1823 // </editor-fold>
1825 // <editor-fold defaultstate="collapsed" desc="getBounds">
1826 /**
1827 * Return list of bounds of the given type variable.
1828 */
1829 public List<Type> getBounds(TypeVar t) {
1830 if (t.bound.isErroneous() || !t.bound.isCompound())
1831 return List.of(t.bound);
1832 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
1833 return interfaces(t).prepend(supertype(t));
1834 else
1835 // No superclass was given in bounds.
1836 // In this case, supertype is Object, erasure is first interface.
1837 return interfaces(t);
1838 }
1839 // </editor-fold>
1841 // <editor-fold defaultstate="collapsed" desc="classBound">
1842 /**
1843 * If the given type is a (possibly selected) type variable,
1844 * return the bounding class of this type, otherwise return the
1845 * type itself.
1846 */
1847 public Type classBound(Type t) {
1848 return classBound.visit(t);
1849 }
1850 // where
1851 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
1853 public Type visitType(Type t, Void ignored) {
1854 return t;
1855 }
1857 @Override
1858 public Type visitClassType(ClassType t, Void ignored) {
1859 Type outer1 = classBound(t.getEnclosingType());
1860 if (outer1 != t.getEnclosingType())
1861 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
1862 else
1863 return t;
1864 }
1866 @Override
1867 public Type visitTypeVar(TypeVar t, Void ignored) {
1868 return classBound(supertype(t));
1869 }
1871 @Override
1872 public Type visitErrorType(ErrorType t, Void ignored) {
1873 return t;
1874 }
1875 };
1876 // </editor-fold>
1878 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
1879 /**
1880 * Returns true iff the first signature is a <em>sub
1881 * signature</em> of the other. This is <b>not</b> an equivalence
1882 * relation.
1883 *
1884 * @see "The Java Language Specification, Third Ed. (8.4.2)."
1885 * @see #overrideEquivalent(Type t, Type s)
1886 * @param t first signature (possibly raw).
1887 * @param s second signature (could be subjected to erasure).
1888 * @return true if t is a sub signature of s.
1889 */
1890 public boolean isSubSignature(Type t, Type s) {
1891 return hasSameArgs(t, s) || hasSameArgs(t, erasure(s));
1892 }
1894 /**
1895 * Returns true iff these signatures are related by <em>override
1896 * equivalence</em>. This is the natural extension of
1897 * isSubSignature to an equivalence relation.
1898 *
1899 * @see "The Java Language Specification, Third Ed. (8.4.2)."
1900 * @see #isSubSignature(Type t, Type s)
1901 * @param t a signature (possible raw, could be subjected to
1902 * erasure).
1903 * @param s a signature (possible raw, could be subjected to
1904 * erasure).
1905 * @return true if either argument is a sub signature of the other.
1906 */
1907 public boolean overrideEquivalent(Type t, Type s) {
1908 return hasSameArgs(t, s) ||
1909 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
1910 }
1912 /**
1913 * Does t have the same arguments as s? It is assumed that both
1914 * types are (possibly polymorphic) method types. Monomorphic
1915 * method types "have the same arguments", if their argument lists
1916 * are equal. Polymorphic method types "have the same arguments",
1917 * if they have the same arguments after renaming all type
1918 * variables of one to corresponding type variables in the other,
1919 * where correspondence is by position in the type parameter list.
1920 */
1921 public boolean hasSameArgs(Type t, Type s) {
1922 return hasSameArgs.visit(t, s);
1923 }
1924 // where
1925 private TypeRelation hasSameArgs = new TypeRelation() {
1927 public Boolean visitType(Type t, Type s) {
1928 throw new AssertionError();
1929 }
1931 @Override
1932 public Boolean visitMethodType(MethodType t, Type s) {
1933 return s.tag == METHOD
1934 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
1935 }
1937 @Override
1938 public Boolean visitForAll(ForAll t, Type s) {
1939 if (s.tag != FORALL)
1940 return false;
1942 ForAll forAll = (ForAll)s;
1943 return hasSameBounds(t, forAll)
1944 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1945 }
1947 @Override
1948 public Boolean visitErrorType(ErrorType t, Type s) {
1949 return false;
1950 }
1951 };
1952 // </editor-fold>
1954 // <editor-fold defaultstate="collapsed" desc="subst">
1955 public List<Type> subst(List<Type> ts,
1956 List<Type> from,
1957 List<Type> to) {
1958 return new Subst(from, to).subst(ts);
1959 }
1961 /**
1962 * Substitute all occurrences of a type in `from' with the
1963 * corresponding type in `to' in 't'. Match lists `from' and `to'
1964 * from the right: If lists have different length, discard leading
1965 * elements of the longer list.
1966 */
1967 public Type subst(Type t, List<Type> from, List<Type> to) {
1968 return new Subst(from, to).subst(t);
1969 }
1971 private class Subst extends UnaryVisitor<Type> {
1972 List<Type> from;
1973 List<Type> to;
1975 public Subst(List<Type> from, List<Type> to) {
1976 int fromLength = from.length();
1977 int toLength = to.length();
1978 while (fromLength > toLength) {
1979 fromLength--;
1980 from = from.tail;
1981 }
1982 while (fromLength < toLength) {
1983 toLength--;
1984 to = to.tail;
1985 }
1986 this.from = from;
1987 this.to = to;
1988 }
1990 Type subst(Type t) {
1991 if (from.tail == null)
1992 return t;
1993 else
1994 return visit(t);
1995 }
1997 List<Type> subst(List<Type> ts) {
1998 if (from.tail == null)
1999 return ts;
2000 boolean wild = false;
2001 if (ts.nonEmpty() && from.nonEmpty()) {
2002 Type head1 = subst(ts.head);
2003 List<Type> tail1 = subst(ts.tail);
2004 if (head1 != ts.head || tail1 != ts.tail)
2005 return tail1.prepend(head1);
2006 }
2007 return ts;
2008 }
2010 public Type visitType(Type t, Void ignored) {
2011 return t;
2012 }
2014 @Override
2015 public Type visitMethodType(MethodType t, Void ignored) {
2016 List<Type> argtypes = subst(t.argtypes);
2017 Type restype = subst(t.restype);
2018 List<Type> thrown = subst(t.thrown);
2019 if (argtypes == t.argtypes &&
2020 restype == t.restype &&
2021 thrown == t.thrown)
2022 return t;
2023 else
2024 return new MethodType(argtypes, restype, thrown, t.tsym);
2025 }
2027 @Override
2028 public Type visitTypeVar(TypeVar t, Void ignored) {
2029 for (List<Type> from = this.from, to = this.to;
2030 from.nonEmpty();
2031 from = from.tail, to = to.tail) {
2032 if (t == from.head) {
2033 return to.head.withTypeVar(t);
2034 }
2035 }
2036 return t;
2037 }
2039 @Override
2040 public Type visitClassType(ClassType t, Void ignored) {
2041 if (!t.isCompound()) {
2042 List<Type> typarams = t.getTypeArguments();
2043 List<Type> typarams1 = subst(typarams);
2044 Type outer = t.getEnclosingType();
2045 Type outer1 = subst(outer);
2046 if (typarams1 == typarams && outer1 == outer)
2047 return t;
2048 else
2049 return new ClassType(outer1, typarams1, t.tsym);
2050 } else {
2051 Type st = subst(supertype(t));
2052 List<Type> is = upperBounds(subst(interfaces(t)));
2053 if (st == supertype(t) && is == interfaces(t))
2054 return t;
2055 else
2056 return makeCompoundType(is.prepend(st));
2057 }
2058 }
2060 @Override
2061 public Type visitWildcardType(WildcardType t, Void ignored) {
2062 Type bound = t.type;
2063 if (t.kind != BoundKind.UNBOUND)
2064 bound = subst(bound);
2065 if (bound == t.type) {
2066 return t;
2067 } else {
2068 if (t.isExtendsBound() && bound.isExtendsBound())
2069 bound = upperBound(bound);
2070 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2071 }
2072 }
2074 @Override
2075 public Type visitArrayType(ArrayType t, Void ignored) {
2076 Type elemtype = subst(t.elemtype);
2077 if (elemtype == t.elemtype)
2078 return t;
2079 else
2080 return new ArrayType(upperBound(elemtype), t.tsym);
2081 }
2083 @Override
2084 public Type visitForAll(ForAll t, Void ignored) {
2085 List<Type> tvars1 = substBounds(t.tvars, from, to);
2086 Type qtype1 = subst(t.qtype);
2087 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2088 return t;
2089 } else if (tvars1 == t.tvars) {
2090 return new ForAll(tvars1, qtype1);
2091 } else {
2092 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2093 }
2094 }
2096 @Override
2097 public Type visitErrorType(ErrorType t, Void ignored) {
2098 return t;
2099 }
2100 }
2102 public List<Type> substBounds(List<Type> tvars,
2103 List<Type> from,
2104 List<Type> to) {
2105 if (tvars.isEmpty())
2106 return tvars;
2107 if (tvars.tail.isEmpty())
2108 // fast common case
2109 return List.<Type>of(substBound((TypeVar)tvars.head, from, to));
2110 ListBuffer<Type> newBoundsBuf = lb();
2111 boolean changed = false;
2112 // calculate new bounds
2113 for (Type t : tvars) {
2114 TypeVar tv = (TypeVar) t;
2115 Type bound = subst(tv.bound, from, to);
2116 if (bound != tv.bound)
2117 changed = true;
2118 newBoundsBuf.append(bound);
2119 }
2120 if (!changed)
2121 return tvars;
2122 ListBuffer<Type> newTvars = lb();
2123 // create new type variables without bounds
2124 for (Type t : tvars) {
2125 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2126 }
2127 // the new bounds should use the new type variables in place
2128 // of the old
2129 List<Type> newBounds = newBoundsBuf.toList();
2130 from = tvars;
2131 to = newTvars.toList();
2132 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2133 newBounds.head = subst(newBounds.head, from, to);
2134 }
2135 newBounds = newBoundsBuf.toList();
2136 // set the bounds of new type variables to the new bounds
2137 for (Type t : newTvars.toList()) {
2138 TypeVar tv = (TypeVar) t;
2139 tv.bound = newBounds.head;
2140 newBounds = newBounds.tail;
2141 }
2142 return newTvars.toList();
2143 }
2145 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2146 Type bound1 = subst(t.bound, from, to);
2147 if (bound1 == t.bound)
2148 return t;
2149 else
2150 return new TypeVar(t.tsym, bound1, syms.botType);
2151 }
2152 // </editor-fold>
2154 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2155 /**
2156 * Does t have the same bounds for quantified variables as s?
2157 */
2158 boolean hasSameBounds(ForAll t, ForAll s) {
2159 List<Type> l1 = t.tvars;
2160 List<Type> l2 = s.tvars;
2161 while (l1.nonEmpty() && l2.nonEmpty() &&
2162 isSameType(l1.head.getUpperBound(),
2163 subst(l2.head.getUpperBound(),
2164 s.tvars,
2165 t.tvars))) {
2166 l1 = l1.tail;
2167 l2 = l2.tail;
2168 }
2169 return l1.isEmpty() && l2.isEmpty();
2170 }
2171 // </editor-fold>
2173 // <editor-fold defaultstate="collapsed" desc="newInstances">
2174 /** Create new vector of type variables from list of variables
2175 * changing all recursive bounds from old to new list.
2176 */
2177 public List<Type> newInstances(List<Type> tvars) {
2178 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2179 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2180 TypeVar tv = (TypeVar) l.head;
2181 tv.bound = subst(tv.bound, tvars, tvars1);
2182 }
2183 return tvars1;
2184 }
2185 static private Mapping newInstanceFun = new Mapping("newInstanceFun") {
2186 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2187 };
2188 // </editor-fold>
2190 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2191 public Type createErrorType(Type originalType) {
2192 return new ErrorType(originalType, syms.errSymbol);
2193 }
2195 public Type createErrorType(ClassSymbol c, Type originalType) {
2196 return new ErrorType(c, originalType);
2197 }
2199 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
2200 return new ErrorType(name, container, originalType);
2201 }
2202 // </editor-fold>
2204 // <editor-fold defaultstate="collapsed" desc="rank">
2205 /**
2206 * The rank of a class is the length of the longest path between
2207 * the class and java.lang.Object in the class inheritance
2208 * graph. Undefined for all but reference types.
2209 */
2210 public int rank(Type t) {
2211 switch(t.tag) {
2212 case CLASS: {
2213 ClassType cls = (ClassType)t;
2214 if (cls.rank_field < 0) {
2215 Name fullname = cls.tsym.getQualifiedName();
2216 if (fullname == names.java_lang_Object)
2217 cls.rank_field = 0;
2218 else {
2219 int r = rank(supertype(cls));
2220 for (List<Type> l = interfaces(cls);
2221 l.nonEmpty();
2222 l = l.tail) {
2223 if (rank(l.head) > r)
2224 r = rank(l.head);
2225 }
2226 cls.rank_field = r + 1;
2227 }
2228 }
2229 return cls.rank_field;
2230 }
2231 case TYPEVAR: {
2232 TypeVar tvar = (TypeVar)t;
2233 if (tvar.rank_field < 0) {
2234 int r = rank(supertype(tvar));
2235 for (List<Type> l = interfaces(tvar);
2236 l.nonEmpty();
2237 l = l.tail) {
2238 if (rank(l.head) > r) r = rank(l.head);
2239 }
2240 tvar.rank_field = r + 1;
2241 }
2242 return tvar.rank_field;
2243 }
2244 case ERROR:
2245 return 0;
2246 default:
2247 throw new AssertionError();
2248 }
2249 }
2250 // </editor-fold>
2252 // <editor-fold defaultstate="collapsed" desc="toString">
2253 /**
2254 * This toString is slightly more descriptive than the one on Type.
2255 */
2256 public String toString(Type t) {
2257 if (t.tag == FORALL) {
2258 ForAll forAll = (ForAll)t;
2259 return typaramsString(forAll.tvars) + forAll.qtype;
2260 }
2261 return "" + t;
2262 }
2263 // where
2264 private String typaramsString(List<Type> tvars) {
2265 StringBuffer s = new StringBuffer();
2266 s.append('<');
2267 boolean first = true;
2268 for (Type t : tvars) {
2269 if (!first) s.append(", ");
2270 first = false;
2271 appendTyparamString(((TypeVar)t), s);
2272 }
2273 s.append('>');
2274 return s.toString();
2275 }
2276 private void appendTyparamString(TypeVar t, StringBuffer buf) {
2277 buf.append(t);
2278 if (t.bound == null ||
2279 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
2280 return;
2281 buf.append(" extends "); // Java syntax; no need for i18n
2282 Type bound = t.bound;
2283 if (!bound.isCompound()) {
2284 buf.append(bound);
2285 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
2286 buf.append(supertype(t));
2287 for (Type intf : interfaces(t)) {
2288 buf.append('&');
2289 buf.append(intf);
2290 }
2291 } else {
2292 // No superclass was given in bounds.
2293 // In this case, supertype is Object, erasure is first interface.
2294 boolean first = true;
2295 for (Type intf : interfaces(t)) {
2296 if (!first) buf.append('&');
2297 first = false;
2298 buf.append(intf);
2299 }
2300 }
2301 }
2302 // </editor-fold>
2304 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
2305 /**
2306 * A cache for closures.
2307 *
2308 * <p>A closure is a list of all the supertypes and interfaces of
2309 * a class or interface type, ordered by ClassSymbol.precedes
2310 * (that is, subclasses come first, arbitrary but fixed
2311 * otherwise).
2312 */
2313 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
2315 /**
2316 * Returns the closure of a class or interface type.
2317 */
2318 public List<Type> closure(Type t) {
2319 List<Type> cl = closureCache.get(t);
2320 if (cl == null) {
2321 Type st = supertype(t);
2322 if (!t.isCompound()) {
2323 if (st.tag == CLASS) {
2324 cl = insert(closure(st), t);
2325 } else if (st.tag == TYPEVAR) {
2326 cl = closure(st).prepend(t);
2327 } else {
2328 cl = List.of(t);
2329 }
2330 } else {
2331 cl = closure(supertype(t));
2332 }
2333 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
2334 cl = union(cl, closure(l.head));
2335 closureCache.put(t, cl);
2336 }
2337 return cl;
2338 }
2340 /**
2341 * Insert a type in a closure
2342 */
2343 public List<Type> insert(List<Type> cl, Type t) {
2344 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
2345 return cl.prepend(t);
2346 } else if (cl.head.tsym.precedes(t.tsym, this)) {
2347 return insert(cl.tail, t).prepend(cl.head);
2348 } else {
2349 return cl;
2350 }
2351 }
2353 /**
2354 * Form the union of two closures
2355 */
2356 public List<Type> union(List<Type> cl1, List<Type> cl2) {
2357 if (cl1.isEmpty()) {
2358 return cl2;
2359 } else if (cl2.isEmpty()) {
2360 return cl1;
2361 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
2362 return union(cl1.tail, cl2).prepend(cl1.head);
2363 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
2364 return union(cl1, cl2.tail).prepend(cl2.head);
2365 } else {
2366 return union(cl1.tail, cl2.tail).prepend(cl1.head);
2367 }
2368 }
2370 /**
2371 * Intersect two closures
2372 */
2373 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
2374 if (cl1 == cl2)
2375 return cl1;
2376 if (cl1.isEmpty() || cl2.isEmpty())
2377 return List.nil();
2378 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
2379 return intersect(cl1.tail, cl2);
2380 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
2381 return intersect(cl1, cl2.tail);
2382 if (isSameType(cl1.head, cl2.head))
2383 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
2384 if (cl1.head.tsym == cl2.head.tsym &&
2385 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
2386 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
2387 Type merge = merge(cl1.head,cl2.head);
2388 return intersect(cl1.tail, cl2.tail).prepend(merge);
2389 }
2390 if (cl1.head.isRaw() || cl2.head.isRaw())
2391 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
2392 }
2393 return intersect(cl1.tail, cl2.tail);
2394 }
2395 // where
2396 class TypePair {
2397 final Type t1;
2398 final Type t2;
2399 TypePair(Type t1, Type t2) {
2400 this.t1 = t1;
2401 this.t2 = t2;
2402 }
2403 @Override
2404 public int hashCode() {
2405 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
2406 }
2407 @Override
2408 public boolean equals(Object obj) {
2409 if (!(obj instanceof TypePair))
2410 return false;
2411 TypePair typePair = (TypePair)obj;
2412 return isSameType(t1, typePair.t1)
2413 && isSameType(t2, typePair.t2);
2414 }
2415 }
2416 Set<TypePair> mergeCache = new HashSet<TypePair>();
2417 private Type merge(Type c1, Type c2) {
2418 ClassType class1 = (ClassType) c1;
2419 List<Type> act1 = class1.getTypeArguments();
2420 ClassType class2 = (ClassType) c2;
2421 List<Type> act2 = class2.getTypeArguments();
2422 ListBuffer<Type> merged = new ListBuffer<Type>();
2423 List<Type> typarams = class1.tsym.type.getTypeArguments();
2425 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
2426 if (containsType(act1.head, act2.head)) {
2427 merged.append(act1.head);
2428 } else if (containsType(act2.head, act1.head)) {
2429 merged.append(act2.head);
2430 } else {
2431 TypePair pair = new TypePair(c1, c2);
2432 Type m;
2433 if (mergeCache.add(pair)) {
2434 m = new WildcardType(lub(upperBound(act1.head),
2435 upperBound(act2.head)),
2436 BoundKind.EXTENDS,
2437 syms.boundClass);
2438 mergeCache.remove(pair);
2439 } else {
2440 m = new WildcardType(syms.objectType,
2441 BoundKind.UNBOUND,
2442 syms.boundClass);
2443 }
2444 merged.append(m.withTypeVar(typarams.head));
2445 }
2446 act1 = act1.tail;
2447 act2 = act2.tail;
2448 typarams = typarams.tail;
2449 }
2450 assert(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
2451 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
2452 }
2454 /**
2455 * Return the minimum type of a closure, a compound type if no
2456 * unique minimum exists.
2457 */
2458 private Type compoundMin(List<Type> cl) {
2459 if (cl.isEmpty()) return syms.objectType;
2460 List<Type> compound = closureMin(cl);
2461 if (compound.isEmpty())
2462 return null;
2463 else if (compound.tail.isEmpty())
2464 return compound.head;
2465 else
2466 return makeCompoundType(compound);
2467 }
2469 /**
2470 * Return the minimum types of a closure, suitable for computing
2471 * compoundMin or glb.
2472 */
2473 private List<Type> closureMin(List<Type> cl) {
2474 ListBuffer<Type> classes = lb();
2475 ListBuffer<Type> interfaces = lb();
2476 while (!cl.isEmpty()) {
2477 Type current = cl.head;
2478 if (current.isInterface())
2479 interfaces.append(current);
2480 else
2481 classes.append(current);
2482 ListBuffer<Type> candidates = lb();
2483 for (Type t : cl.tail) {
2484 if (!isSubtypeNoCapture(current, t))
2485 candidates.append(t);
2486 }
2487 cl = candidates.toList();
2488 }
2489 return classes.appendList(interfaces).toList();
2490 }
2492 /**
2493 * Return the least upper bound of pair of types. if the lub does
2494 * not exist return null.
2495 */
2496 public Type lub(Type t1, Type t2) {
2497 return lub(List.of(t1, t2));
2498 }
2500 /**
2501 * Return the least upper bound (lub) of set of types. If the lub
2502 * does not exist return the type of null (bottom).
2503 */
2504 public Type lub(List<Type> ts) {
2505 final int ARRAY_BOUND = 1;
2506 final int CLASS_BOUND = 2;
2507 int boundkind = 0;
2508 for (Type t : ts) {
2509 switch (t.tag) {
2510 case CLASS:
2511 boundkind |= CLASS_BOUND;
2512 break;
2513 case ARRAY:
2514 boundkind |= ARRAY_BOUND;
2515 break;
2516 case TYPEVAR:
2517 do {
2518 t = t.getUpperBound();
2519 } while (t.tag == TYPEVAR);
2520 if (t.tag == ARRAY) {
2521 boundkind |= ARRAY_BOUND;
2522 } else {
2523 boundkind |= CLASS_BOUND;
2524 }
2525 break;
2526 default:
2527 if (t.isPrimitive())
2528 return syms.errType;
2529 }
2530 }
2531 switch (boundkind) {
2532 case 0:
2533 return syms.botType;
2535 case ARRAY_BOUND:
2536 // calculate lub(A[], B[])
2537 List<Type> elements = Type.map(ts, elemTypeFun);
2538 for (Type t : elements) {
2539 if (t.isPrimitive()) {
2540 // if a primitive type is found, then return
2541 // arraySuperType unless all the types are the
2542 // same
2543 Type first = ts.head;
2544 for (Type s : ts.tail) {
2545 if (!isSameType(first, s)) {
2546 // lub(int[], B[]) is Cloneable & Serializable
2547 return arraySuperType();
2548 }
2549 }
2550 // all the array types are the same, return one
2551 // lub(int[], int[]) is int[]
2552 return first;
2553 }
2554 }
2555 // lub(A[], B[]) is lub(A, B)[]
2556 return new ArrayType(lub(elements), syms.arrayClass);
2558 case CLASS_BOUND:
2559 // calculate lub(A, B)
2560 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
2561 ts = ts.tail;
2562 assert !ts.isEmpty();
2563 List<Type> cl = closure(ts.head);
2564 for (Type t : ts.tail) {
2565 if (t.tag == CLASS || t.tag == TYPEVAR)
2566 cl = intersect(cl, closure(t));
2567 }
2568 return compoundMin(cl);
2570 default:
2571 // calculate lub(A, B[])
2572 List<Type> classes = List.of(arraySuperType());
2573 for (Type t : ts) {
2574 if (t.tag != ARRAY) // Filter out any arrays
2575 classes = classes.prepend(t);
2576 }
2577 // lub(A, B[]) is lub(A, arraySuperType)
2578 return lub(classes);
2579 }
2580 }
2581 // where
2582 private Type arraySuperType = null;
2583 private Type arraySuperType() {
2584 // initialized lazily to avoid problems during compiler startup
2585 if (arraySuperType == null) {
2586 synchronized (this) {
2587 if (arraySuperType == null) {
2588 // JLS 10.8: all arrays implement Cloneable and Serializable.
2589 arraySuperType = makeCompoundType(List.of(syms.serializableType,
2590 syms.cloneableType),
2591 syms.objectType);
2592 }
2593 }
2594 }
2595 return arraySuperType;
2596 }
2597 // </editor-fold>
2599 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
2600 public Type glb(Type t, Type s) {
2601 if (s == null)
2602 return t;
2603 else if (isSubtypeNoCapture(t, s))
2604 return t;
2605 else if (isSubtypeNoCapture(s, t))
2606 return s;
2608 List<Type> closure = union(closure(t), closure(s));
2609 List<Type> bounds = closureMin(closure);
2611 if (bounds.isEmpty()) { // length == 0
2612 return syms.objectType;
2613 } else if (bounds.tail.isEmpty()) { // length == 1
2614 return bounds.head;
2615 } else { // length > 1
2616 int classCount = 0;
2617 for (Type bound : bounds)
2618 if (!bound.isInterface())
2619 classCount++;
2620 if (classCount > 1)
2621 return createErrorType(t);
2622 }
2623 return makeCompoundType(bounds);
2624 }
2625 // </editor-fold>
2627 // <editor-fold defaultstate="collapsed" desc="hashCode">
2628 /**
2629 * Compute a hash code on a type.
2630 */
2631 public static int hashCode(Type t) {
2632 return hashCode.visit(t);
2633 }
2634 // where
2635 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
2637 public Integer visitType(Type t, Void ignored) {
2638 return t.tag;
2639 }
2641 @Override
2642 public Integer visitClassType(ClassType t, Void ignored) {
2643 int result = visit(t.getEnclosingType());
2644 result *= 127;
2645 result += t.tsym.flatName().hashCode();
2646 for (Type s : t.getTypeArguments()) {
2647 result *= 127;
2648 result += visit(s);
2649 }
2650 return result;
2651 }
2653 @Override
2654 public Integer visitWildcardType(WildcardType t, Void ignored) {
2655 int result = t.kind.hashCode();
2656 if (t.type != null) {
2657 result *= 127;
2658 result += visit(t.type);
2659 }
2660 return result;
2661 }
2663 @Override
2664 public Integer visitArrayType(ArrayType t, Void ignored) {
2665 return visit(t.elemtype) + 12;
2666 }
2668 @Override
2669 public Integer visitTypeVar(TypeVar t, Void ignored) {
2670 return System.identityHashCode(t.tsym);
2671 }
2673 @Override
2674 public Integer visitUndetVar(UndetVar t, Void ignored) {
2675 return System.identityHashCode(t);
2676 }
2678 @Override
2679 public Integer visitErrorType(ErrorType t, Void ignored) {
2680 return 0;
2681 }
2682 };
2683 // </editor-fold>
2685 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
2686 /**
2687 * Does t have a result that is a subtype of the result type of s,
2688 * suitable for covariant returns? It is assumed that both types
2689 * are (possibly polymorphic) method types. Monomorphic method
2690 * types are handled in the obvious way. Polymorphic method types
2691 * require renaming all type variables of one to corresponding
2692 * type variables in the other, where correspondence is by
2693 * position in the type parameter list. */
2694 public boolean resultSubtype(Type t, Type s, Warner warner) {
2695 List<Type> tvars = t.getTypeArguments();
2696 List<Type> svars = s.getTypeArguments();
2697 Type tres = t.getReturnType();
2698 Type sres = subst(s.getReturnType(), svars, tvars);
2699 return covariantReturnType(tres, sres, warner);
2700 }
2702 /**
2703 * Return-Type-Substitutable.
2704 * @see <a href="http://java.sun.com/docs/books/jls/">The Java
2705 * Language Specification, Third Ed. (8.4.5)</a>
2706 */
2707 public boolean returnTypeSubstitutable(Type r1, Type r2) {
2708 if (hasSameArgs(r1, r2))
2709 return resultSubtype(r1, r2, Warner.noWarnings);
2710 else
2711 return covariantReturnType(r1.getReturnType(),
2712 erasure(r2.getReturnType()),
2713 Warner.noWarnings);
2714 }
2716 public boolean returnTypeSubstitutable(Type r1,
2717 Type r2, Type r2res,
2718 Warner warner) {
2719 if (isSameType(r1.getReturnType(), r2res))
2720 return true;
2721 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
2722 return false;
2724 if (hasSameArgs(r1, r2))
2725 return covariantReturnType(r1.getReturnType(), r2res, warner);
2726 if (!source.allowCovariantReturns())
2727 return false;
2728 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
2729 return true;
2730 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
2731 return false;
2732 warner.warnUnchecked();
2733 return true;
2734 }
2736 /**
2737 * Is t an appropriate return type in an overrider for a
2738 * method that returns s?
2739 */
2740 public boolean covariantReturnType(Type t, Type s, Warner warner) {
2741 return
2742 isSameType(t, s) ||
2743 source.allowCovariantReturns() &&
2744 !t.isPrimitive() &&
2745 !s.isPrimitive() &&
2746 isAssignable(t, s, warner);
2747 }
2748 // </editor-fold>
2750 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
2751 /**
2752 * Return the class that boxes the given primitive.
2753 */
2754 public ClassSymbol boxedClass(Type t) {
2755 return reader.enterClass(syms.boxedName[t.tag]);
2756 }
2758 /**
2759 * Return the primitive type corresponding to a boxed type.
2760 */
2761 public Type unboxedType(Type t) {
2762 if (allowBoxing) {
2763 for (int i=0; i<syms.boxedName.length; i++) {
2764 Name box = syms.boxedName[i];
2765 if (box != null &&
2766 asSuper(t, reader.enterClass(box)) != null)
2767 return syms.typeOfTag[i];
2768 }
2769 }
2770 return Type.noType;
2771 }
2772 // </editor-fold>
2774 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
2775 /*
2776 * JLS 3rd Ed. 5.1.10 Capture Conversion:
2777 *
2778 * Let G name a generic type declaration with n formal type
2779 * parameters A1 ... An with corresponding bounds U1 ... Un. There
2780 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
2781 * where, for 1 <= i <= n:
2782 *
2783 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
2784 * Si is a fresh type variable whose upper bound is
2785 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
2786 * type.
2787 *
2788 * + If Ti is a wildcard type argument of the form ? extends Bi,
2789 * then Si is a fresh type variable whose upper bound is
2790 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
2791 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
2792 * a compile-time error if for any two classes (not interfaces)
2793 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
2794 *
2795 * + If Ti is a wildcard type argument of the form ? super Bi,
2796 * then Si is a fresh type variable whose upper bound is
2797 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
2798 *
2799 * + Otherwise, Si = Ti.
2800 *
2801 * Capture conversion on any type other than a parameterized type
2802 * (4.5) acts as an identity conversion (5.1.1). Capture
2803 * conversions never require a special action at run time and
2804 * therefore never throw an exception at run time.
2805 *
2806 * Capture conversion is not applied recursively.
2807 */
2808 /**
2809 * Capture conversion as specified by JLS 3rd Ed.
2810 */
2811 public Type capture(Type t) {
2812 if (t.tag != CLASS)
2813 return t;
2814 ClassType cls = (ClassType)t;
2815 if (cls.isRaw() || !cls.isParameterized())
2816 return cls;
2818 ClassType G = (ClassType)cls.asElement().asType();
2819 List<Type> A = G.getTypeArguments();
2820 List<Type> T = cls.getTypeArguments();
2821 List<Type> S = freshTypeVariables(T);
2823 List<Type> currentA = A;
2824 List<Type> currentT = T;
2825 List<Type> currentS = S;
2826 boolean captured = false;
2827 while (!currentA.isEmpty() &&
2828 !currentT.isEmpty() &&
2829 !currentS.isEmpty()) {
2830 if (currentS.head != currentT.head) {
2831 captured = true;
2832 WildcardType Ti = (WildcardType)currentT.head;
2833 Type Ui = currentA.head.getUpperBound();
2834 CapturedType Si = (CapturedType)currentS.head;
2835 if (Ui == null)
2836 Ui = syms.objectType;
2837 switch (Ti.kind) {
2838 case UNBOUND:
2839 Si.bound = subst(Ui, A, S);
2840 Si.lower = syms.botType;
2841 break;
2842 case EXTENDS:
2843 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
2844 Si.lower = syms.botType;
2845 break;
2846 case SUPER:
2847 Si.bound = subst(Ui, A, S);
2848 Si.lower = Ti.getSuperBound();
2849 break;
2850 }
2851 if (Si.bound == Si.lower)
2852 currentS.head = Si.bound;
2853 }
2854 currentA = currentA.tail;
2855 currentT = currentT.tail;
2856 currentS = currentS.tail;
2857 }
2858 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
2859 return erasure(t); // some "rare" type involved
2861 if (captured)
2862 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
2863 else
2864 return t;
2865 }
2866 // where
2867 private List<Type> freshTypeVariables(List<Type> types) {
2868 ListBuffer<Type> result = lb();
2869 for (Type t : types) {
2870 if (t.tag == WILDCARD) {
2871 Type bound = ((WildcardType)t).getExtendsBound();
2872 if (bound == null)
2873 bound = syms.objectType;
2874 result.append(new CapturedType(capturedName,
2875 syms.noSymbol,
2876 bound,
2877 syms.botType,
2878 (WildcardType)t));
2879 } else {
2880 result.append(t);
2881 }
2882 }
2883 return result.toList();
2884 }
2885 // </editor-fold>
2887 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
2888 private List<Type> upperBounds(List<Type> ss) {
2889 if (ss.isEmpty()) return ss;
2890 Type head = upperBound(ss.head);
2891 List<Type> tail = upperBounds(ss.tail);
2892 if (head != ss.head || tail != ss.tail)
2893 return tail.prepend(head);
2894 else
2895 return ss;
2896 }
2898 private boolean sideCast(Type from, Type to, Warner warn) {
2899 // We are casting from type $from$ to type $to$, which are
2900 // non-final unrelated types. This method
2901 // tries to reject a cast by transferring type parameters
2902 // from $to$ to $from$ by common superinterfaces.
2903 boolean reverse = false;
2904 Type target = to;
2905 if ((to.tsym.flags() & INTERFACE) == 0) {
2906 assert (from.tsym.flags() & INTERFACE) != 0;
2907 reverse = true;
2908 to = from;
2909 from = target;
2910 }
2911 List<Type> commonSupers = superClosure(to, erasure(from));
2912 boolean giveWarning = commonSupers.isEmpty();
2913 // The arguments to the supers could be unified here to
2914 // get a more accurate analysis
2915 while (commonSupers.nonEmpty()) {
2916 Type t1 = asSuper(from, commonSupers.head.tsym);
2917 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
2918 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
2919 return false;
2920 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
2921 commonSupers = commonSupers.tail;
2922 }
2923 if (giveWarning && !isReifiable(to))
2924 warn.warnUnchecked();
2925 if (!source.allowCovariantReturns())
2926 // reject if there is a common method signature with
2927 // incompatible return types.
2928 chk.checkCompatibleAbstracts(warn.pos(), from, to);
2929 return true;
2930 }
2932 private boolean sideCastFinal(Type from, Type to, Warner warn) {
2933 // We are casting from type $from$ to type $to$, which are
2934 // unrelated types one of which is final and the other of
2935 // which is an interface. This method
2936 // tries to reject a cast by transferring type parameters
2937 // from the final class to the interface.
2938 boolean reverse = false;
2939 Type target = to;
2940 if ((to.tsym.flags() & INTERFACE) == 0) {
2941 assert (from.tsym.flags() & INTERFACE) != 0;
2942 reverse = true;
2943 to = from;
2944 from = target;
2945 }
2946 assert (from.tsym.flags() & FINAL) != 0;
2947 Type t1 = asSuper(from, to.tsym);
2948 if (t1 == null) return false;
2949 Type t2 = to;
2950 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
2951 return false;
2952 if (!source.allowCovariantReturns())
2953 // reject if there is a common method signature with
2954 // incompatible return types.
2955 chk.checkCompatibleAbstracts(warn.pos(), from, to);
2956 if (!isReifiable(target) &&
2957 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
2958 warn.warnUnchecked();
2959 return true;
2960 }
2962 private boolean giveWarning(Type from, Type to) {
2963 // To and from are (possibly different) parameterizations
2964 // of the same class or interface
2965 return to.isParameterized() && !containsType(to.getTypeArguments(), from.getTypeArguments());
2966 }
2968 private List<Type> superClosure(Type t, Type s) {
2969 List<Type> cl = List.nil();
2970 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
2971 if (isSubtype(s, erasure(l.head))) {
2972 cl = insert(cl, l.head);
2973 } else {
2974 cl = union(cl, superClosure(l.head, s));
2975 }
2976 }
2977 return cl;
2978 }
2980 private boolean containsTypeEquivalent(Type t, Type s) {
2981 return
2982 isSameType(t, s) || // shortcut
2983 containsType(t, s) && containsType(s, t);
2984 }
2986 /**
2987 * Adapt a type by computing a substitution which maps a source
2988 * type to a target type.
2989 *
2990 * @param source the source type
2991 * @param target the target type
2992 * @param from the type variables of the computed substitution
2993 * @param to the types of the computed substitution.
2994 */
2995 public void adapt(Type source,
2996 Type target,
2997 ListBuffer<Type> from,
2998 ListBuffer<Type> to) throws AdaptFailure {
2999 Map<Symbol,Type> mapping = new HashMap<Symbol,Type>();
3000 adaptRecursive(source, target, from, to, mapping);
3001 List<Type> fromList = from.toList();
3002 List<Type> toList = to.toList();
3003 while (!fromList.isEmpty()) {
3004 Type val = mapping.get(fromList.head.tsym);
3005 if (toList.head != val)
3006 toList.head = val;
3007 fromList = fromList.tail;
3008 toList = toList.tail;
3009 }
3010 }
3011 // where
3012 private void adaptRecursive(Type source,
3013 Type target,
3014 ListBuffer<Type> from,
3015 ListBuffer<Type> to,
3016 Map<Symbol,Type> mapping) throws AdaptFailure {
3017 if (source.tag == TYPEVAR) {
3018 // Check to see if there is
3019 // already a mapping for $source$, in which case
3020 // the old mapping will be merged with the new
3021 Type val = mapping.get(source.tsym);
3022 if (val != null) {
3023 if (val.isSuperBound() && target.isSuperBound()) {
3024 val = isSubtype(lowerBound(val), lowerBound(target))
3025 ? target : val;
3026 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3027 val = isSubtype(upperBound(val), upperBound(target))
3028 ? val : target;
3029 } else if (!isSameType(val, target)) {
3030 throw new AdaptFailure();
3031 }
3032 } else {
3033 val = target;
3034 from.append(source);
3035 to.append(target);
3036 }
3037 mapping.put(source.tsym, val);
3038 } else if (source.tag == target.tag) {
3039 switch (source.tag) {
3040 case CLASS:
3041 adapt(source.allparams(), target.allparams(),
3042 from, to, mapping);
3043 break;
3044 case ARRAY:
3045 adaptRecursive(elemtype(source), elemtype(target),
3046 from, to, mapping);
3047 break;
3048 case WILDCARD:
3049 if (source.isExtendsBound()) {
3050 adaptRecursive(upperBound(source), upperBound(target),
3051 from, to, mapping);
3052 } else if (source.isSuperBound()) {
3053 adaptRecursive(lowerBound(source), lowerBound(target),
3054 from, to, mapping);
3055 }
3056 break;
3057 }
3058 }
3059 }
3060 public static class AdaptFailure extends Exception {
3061 static final long serialVersionUID = -7490231548272701566L;
3062 }
3064 /**
3065 * Adapt a type by computing a substitution which maps a list of
3066 * source types to a list of target types.
3067 *
3068 * @param source the source type
3069 * @param target the target type
3070 * @param from the type variables of the computed substitution
3071 * @param to the types of the computed substitution.
3072 */
3073 private void adapt(List<Type> source,
3074 List<Type> target,
3075 ListBuffer<Type> from,
3076 ListBuffer<Type> to,
3077 Map<Symbol,Type> mapping) throws AdaptFailure {
3078 if (source.length() == target.length()) {
3079 while (source.nonEmpty()) {
3080 adaptRecursive(source.head, target.head, from, to, mapping);
3081 source = source.tail;
3082 target = target.tail;
3083 }
3084 }
3085 }
3087 private void adaptSelf(Type t,
3088 ListBuffer<Type> from,
3089 ListBuffer<Type> to) {
3090 try {
3091 //if (t.tsym.type != t)
3092 adapt(t.tsym.type, t, from, to);
3093 } catch (AdaptFailure ex) {
3094 // Adapt should never fail calculating a mapping from
3095 // t.tsym.type to t as there can be no merge problem.
3096 throw new AssertionError(ex);
3097 }
3098 }
3100 /**
3101 * Rewrite all type variables (universal quantifiers) in the given
3102 * type to wildcards (existential quantifiers). This is used to
3103 * determine if a cast is allowed. For example, if high is true
3104 * and {@code T <: Number}, then {@code List<T>} is rewritten to
3105 * {@code List<? extends Number>}. Since {@code List<Integer> <:
3106 * List<? extends Number>} a {@code List<T>} can be cast to {@code
3107 * List<Integer>} with a warning.
3108 * @param t a type
3109 * @param high if true return an upper bound; otherwise a lower
3110 * bound
3111 * @param rewriteTypeVars only rewrite captured wildcards if false;
3112 * otherwise rewrite all type variables
3113 * @return the type rewritten with wildcards (existential
3114 * quantifiers) only
3115 */
3116 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
3117 ListBuffer<Type> from = new ListBuffer<Type>();
3118 ListBuffer<Type> to = new ListBuffer<Type>();
3119 adaptSelf(t, from, to);
3120 ListBuffer<Type> rewritten = new ListBuffer<Type>();
3121 List<Type> formals = from.toList();
3122 boolean changed = false;
3123 for (Type arg : to.toList()) {
3124 Type bound;
3125 if (rewriteTypeVars && arg.tag == TYPEVAR) {
3126 TypeVar tv = (TypeVar)arg;
3127 bound = high ? tv.bound : syms.botType;
3128 } else {
3129 bound = high ? upperBound(arg) : lowerBound(arg);
3130 }
3131 Type newarg = bound;
3132 if (arg != bound) {
3133 changed = true;
3134 newarg = high ? makeExtendsWildcard(bound, (TypeVar)formals.head)
3135 : makeSuperWildcard(bound, (TypeVar)formals.head);
3136 }
3137 rewritten.append(newarg);
3138 formals = formals.tail;
3139 }
3140 if (changed)
3141 return subst(t.tsym.type, from.toList(), rewritten.toList());
3142 else
3143 return t;
3144 }
3146 /**
3147 * Create a wildcard with the given upper (extends) bound; create
3148 * an unbounded wildcard if bound is Object.
3149 *
3150 * @param bound the upper bound
3151 * @param formal the formal type parameter that will be
3152 * substituted by the wildcard
3153 */
3154 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
3155 if (bound == syms.objectType) {
3156 return new WildcardType(syms.objectType,
3157 BoundKind.UNBOUND,
3158 syms.boundClass,
3159 formal);
3160 } else {
3161 return new WildcardType(bound,
3162 BoundKind.EXTENDS,
3163 syms.boundClass,
3164 formal);
3165 }
3166 }
3168 /**
3169 * Create a wildcard with the given lower (super) bound; create an
3170 * unbounded wildcard if bound is bottom (type of {@code null}).
3171 *
3172 * @param bound the lower bound
3173 * @param formal the formal type parameter that will be
3174 * substituted by the wildcard
3175 */
3176 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
3177 if (bound.tag == BOT) {
3178 return new WildcardType(syms.objectType,
3179 BoundKind.UNBOUND,
3180 syms.boundClass,
3181 formal);
3182 } else {
3183 return new WildcardType(bound,
3184 BoundKind.SUPER,
3185 syms.boundClass,
3186 formal);
3187 }
3188 }
3190 /**
3191 * A wrapper for a type that allows use in sets.
3192 */
3193 class SingletonType {
3194 final Type t;
3195 SingletonType(Type t) {
3196 this.t = t;
3197 }
3198 public int hashCode() {
3199 return Types.this.hashCode(t);
3200 }
3201 public boolean equals(Object obj) {
3202 return (obj instanceof SingletonType) &&
3203 isSameType(t, ((SingletonType)obj).t);
3204 }
3205 public String toString() {
3206 return t.toString();
3207 }
3208 }
3209 // </editor-fold>
3211 // <editor-fold defaultstate="collapsed" desc="Visitors">
3212 /**
3213 * A default visitor for types. All visitor methods except
3214 * visitType are implemented by delegating to visitType. Concrete
3215 * subclasses must provide an implementation of visitType and can
3216 * override other methods as needed.
3217 *
3218 * @param <R> the return type of the operation implemented by this
3219 * visitor; use Void if no return type is needed.
3220 * @param <S> the type of the second argument (the first being the
3221 * type itself) of the operation implemented by this visitor; use
3222 * Void if a second argument is not needed.
3223 */
3224 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
3225 final public R visit(Type t, S s) { return t.accept(this, s); }
3226 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
3227 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
3228 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
3229 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
3230 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
3231 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
3232 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
3233 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
3234 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
3235 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
3236 }
3238 /**
3239 * A <em>simple</em> visitor for types. This visitor is simple as
3240 * captured wildcards, for-all types (generic methods), and
3241 * undetermined type variables (part of inference) are hidden.
3242 * Captured wildcards are hidden by treating them as type
3243 * variables and the rest are hidden by visiting their qtypes.
3244 *
3245 * @param <R> the return type of the operation implemented by this
3246 * visitor; use Void if no return type is needed.
3247 * @param <S> the type of the second argument (the first being the
3248 * type itself) of the operation implemented by this visitor; use
3249 * Void if a second argument is not needed.
3250 */
3251 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
3252 @Override
3253 public R visitCapturedType(CapturedType t, S s) {
3254 return visitTypeVar(t, s);
3255 }
3256 @Override
3257 public R visitForAll(ForAll t, S s) {
3258 return visit(t.qtype, s);
3259 }
3260 @Override
3261 public R visitUndetVar(UndetVar t, S s) {
3262 return visit(t.qtype, s);
3263 }
3264 }
3266 /**
3267 * A plain relation on types. That is a 2-ary function on the
3268 * form Type × Type → Boolean.
3269 * <!-- In plain text: Type x Type -> Boolean -->
3270 */
3271 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
3273 /**
3274 * A convenience visitor for implementing operations that only
3275 * require one argument (the type itself), that is, unary
3276 * operations.
3277 *
3278 * @param <R> the return type of the operation implemented by this
3279 * visitor; use Void if no return type is needed.
3280 */
3281 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
3282 final public R visit(Type t) { return t.accept(this, null); }
3283 }
3285 /**
3286 * A visitor for implementing a mapping from types to types. The
3287 * default behavior of this class is to implement the identity
3288 * mapping (mapping a type to itself). This can be overridden in
3289 * subclasses.
3290 *
3291 * @param <S> the type of the second argument (the first being the
3292 * type itself) of this mapping; use Void if a second argument is
3293 * not needed.
3294 */
3295 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
3296 final public Type visit(Type t) { return t.accept(this, null); }
3297 public Type visitType(Type t, S s) { return t; }
3298 }
3299 // </editor-fold>
3300 }
