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src/share/classes/com/sun/tools/javac/code/Types.java@b5d0b8effc85
src/share/classes/com/sun/tools/javac/code/Types.java
Mon, 17 Oct 2011 12:54:33 +0100
- author
- mcimadamore
- date
- Mon, 17 Oct 2011 12:54:33 +0100
- changeset 1108
- b5d0b8effc85
- parent 1093
- c0835c8489b0
- child 1177
- 70d92518063e
- permissions
- -rw-r--r--
7097436: Project Coin: duplicate varargs warnings on method annotated with @SafeVarargs
Summary: Duplicate aliasing check during subtyping leads to spurious varargs diagnostic
Reviewed-by: jjg
1 /*
2 * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
26 package com.sun.tools.javac.code;
28 import java.lang.ref.SoftReference;
29 import java.util.*;
31 import com.sun.tools.javac.util.*;
32 import com.sun.tools.javac.util.List;
34 import com.sun.tools.javac.jvm.ClassReader;
35 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
36 import com.sun.tools.javac.code.Lint.LintCategory;
37 import com.sun.tools.javac.comp.Check;
39 import static com.sun.tools.javac.code.Scope.*;
40 import static com.sun.tools.javac.code.Type.*;
41 import static com.sun.tools.javac.code.TypeTags.*;
42 import static com.sun.tools.javac.code.Symbol.*;
43 import static com.sun.tools.javac.code.Flags.*;
44 import static com.sun.tools.javac.code.BoundKind.*;
45 import static com.sun.tools.javac.util.ListBuffer.lb;
47 /**
48 * Utility class containing various operations on types.
49 *
50 * <p>Unless other names are more illustrative, the following naming
51 * conventions should be observed in this file:
52 *
53 * <dl>
54 * <dt>t</dt>
55 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
56 * <dt>s</dt>
57 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
58 * <dt>ts</dt>
59 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
60 * <dt>ss</dt>
61 * <dd>A second list of types should be named ss.</dd>
62 * </dl>
63 *
64 * <p><b>This is NOT part of any supported API.
65 * If you write code that depends on this, you do so at your own risk.
66 * This code and its internal interfaces are subject to change or
67 * deletion without notice.</b>
68 */
69 public class Types {
70 protected static final Context.Key<Types> typesKey =
71 new Context.Key<Types>();
73 final Symtab syms;
74 final JavacMessages messages;
75 final Names names;
76 final boolean allowBoxing;
77 final boolean allowCovariantReturns;
78 final boolean allowObjectToPrimitiveCast;
79 final ClassReader reader;
80 final Check chk;
81 List<Warner> warnStack = List.nil();
82 final Name capturedName;
84 // <editor-fold defaultstate="collapsed" desc="Instantiating">
85 public static Types instance(Context context) {
86 Types instance = context.get(typesKey);
87 if (instance == null)
88 instance = new Types(context);
89 return instance;
90 }
92 protected Types(Context context) {
93 context.put(typesKey, this);
94 syms = Symtab.instance(context);
95 names = Names.instance(context);
96 Source source = Source.instance(context);
97 allowBoxing = source.allowBoxing();
98 allowCovariantReturns = source.allowCovariantReturns();
99 allowObjectToPrimitiveCast = source.allowObjectToPrimitiveCast();
100 reader = ClassReader.instance(context);
101 chk = Check.instance(context);
102 capturedName = names.fromString("<captured wildcard>");
103 messages = JavacMessages.instance(context);
104 }
105 // </editor-fold>
107 // <editor-fold defaultstate="collapsed" desc="upperBound">
108 /**
109 * The "rvalue conversion".<br>
110 * The upper bound of most types is the type
111 * itself. Wildcards, on the other hand have upper
112 * and lower bounds.
113 * @param t a type
114 * @return the upper bound of the given type
115 */
116 public Type upperBound(Type t) {
117 return upperBound.visit(t);
118 }
119 // where
120 private final MapVisitor<Void> upperBound = new MapVisitor<Void>() {
122 @Override
123 public Type visitWildcardType(WildcardType t, Void ignored) {
124 if (t.isSuperBound())
125 return t.bound == null ? syms.objectType : t.bound.bound;
126 else
127 return visit(t.type);
128 }
130 @Override
131 public Type visitCapturedType(CapturedType t, Void ignored) {
132 return visit(t.bound);
133 }
134 };
135 // </editor-fold>
137 // <editor-fold defaultstate="collapsed" desc="lowerBound">
138 /**
139 * The "lvalue conversion".<br>
140 * The lower bound of most types is the type
141 * itself. Wildcards, on the other hand have upper
142 * and lower bounds.
143 * @param t a type
144 * @return the lower bound of the given type
145 */
146 public Type lowerBound(Type t) {
147 return lowerBound.visit(t);
148 }
149 // where
150 private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() {
152 @Override
153 public Type visitWildcardType(WildcardType t, Void ignored) {
154 return t.isExtendsBound() ? syms.botType : visit(t.type);
155 }
157 @Override
158 public Type visitCapturedType(CapturedType t, Void ignored) {
159 return visit(t.getLowerBound());
160 }
161 };
162 // </editor-fold>
164 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
165 /**
166 * Checks that all the arguments to a class are unbounded
167 * wildcards or something else that doesn't make any restrictions
168 * on the arguments. If a class isUnbounded, a raw super- or
169 * subclass can be cast to it without a warning.
170 * @param t a type
171 * @return true iff the given type is unbounded or raw
172 */
173 public boolean isUnbounded(Type t) {
174 return isUnbounded.visit(t);
175 }
176 // where
177 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
179 public Boolean visitType(Type t, Void ignored) {
180 return true;
181 }
183 @Override
184 public Boolean visitClassType(ClassType t, Void ignored) {
185 List<Type> parms = t.tsym.type.allparams();
186 List<Type> args = t.allparams();
187 while (parms.nonEmpty()) {
188 WildcardType unb = new WildcardType(syms.objectType,
189 BoundKind.UNBOUND,
190 syms.boundClass,
191 (TypeVar)parms.head);
192 if (!containsType(args.head, unb))
193 return false;
194 parms = parms.tail;
195 args = args.tail;
196 }
197 return true;
198 }
199 };
200 // </editor-fold>
202 // <editor-fold defaultstate="collapsed" desc="asSub">
203 /**
204 * Return the least specific subtype of t that starts with symbol
205 * sym. If none exists, return null. The least specific subtype
206 * is determined as follows:
207 *
208 * <p>If there is exactly one parameterized instance of sym that is a
209 * subtype of t, that parameterized instance is returned.<br>
210 * Otherwise, if the plain type or raw type `sym' is a subtype of
211 * type t, the type `sym' itself is returned. Otherwise, null is
212 * returned.
213 */
214 public Type asSub(Type t, Symbol sym) {
215 return asSub.visit(t, sym);
216 }
217 // where
218 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
220 public Type visitType(Type t, Symbol sym) {
221 return null;
222 }
224 @Override
225 public Type visitClassType(ClassType t, Symbol sym) {
226 if (t.tsym == sym)
227 return t;
228 Type base = asSuper(sym.type, t.tsym);
229 if (base == null)
230 return null;
231 ListBuffer<Type> from = new ListBuffer<Type>();
232 ListBuffer<Type> to = new ListBuffer<Type>();
233 try {
234 adapt(base, t, from, to);
235 } catch (AdaptFailure ex) {
236 return null;
237 }
238 Type res = subst(sym.type, from.toList(), to.toList());
239 if (!isSubtype(res, t))
240 return null;
241 ListBuffer<Type> openVars = new ListBuffer<Type>();
242 for (List<Type> l = sym.type.allparams();
243 l.nonEmpty(); l = l.tail)
244 if (res.contains(l.head) && !t.contains(l.head))
245 openVars.append(l.head);
246 if (openVars.nonEmpty()) {
247 if (t.isRaw()) {
248 // The subtype of a raw type is raw
249 res = erasure(res);
250 } else {
251 // Unbound type arguments default to ?
252 List<Type> opens = openVars.toList();
253 ListBuffer<Type> qs = new ListBuffer<Type>();
254 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
255 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head));
256 }
257 res = subst(res, opens, qs.toList());
258 }
259 }
260 return res;
261 }
263 @Override
264 public Type visitErrorType(ErrorType t, Symbol sym) {
265 return t;
266 }
267 };
268 // </editor-fold>
270 // <editor-fold defaultstate="collapsed" desc="isConvertible">
271 /**
272 * Is t a subtype of or convertible via boxing/unboxing
273 * conversion to s?
274 */
275 public boolean isConvertible(Type t, Type s, Warner warn) {
276 if (t.tag == ERROR)
277 return true;
278 boolean tPrimitive = t.isPrimitive();
279 boolean sPrimitive = s.isPrimitive();
280 if (tPrimitive == sPrimitive) {
281 return isSubtypeUnchecked(t, s, warn);
282 }
283 if (!allowBoxing) return false;
284 return tPrimitive
285 ? isSubtype(boxedClass(t).type, s)
286 : isSubtype(unboxedType(t), s);
287 }
289 /**
290 * Is t a subtype of or convertiable via boxing/unboxing
291 * convertions to s?
292 */
293 public boolean isConvertible(Type t, Type s) {
294 return isConvertible(t, s, Warner.noWarnings);
295 }
296 // </editor-fold>
298 // <editor-fold defaultstate="collapsed" desc="isSubtype">
299 /**
300 * Is t an unchecked subtype of s?
301 */
302 public boolean isSubtypeUnchecked(Type t, Type s) {
303 return isSubtypeUnchecked(t, s, Warner.noWarnings);
304 }
305 /**
306 * Is t an unchecked subtype of s?
307 */
308 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
309 boolean result = isSubtypeUncheckedInternal(t, s, warn);
310 if (result) {
311 checkUnsafeVarargsConversion(t, s, warn);
312 }
313 return result;
314 }
315 //where
316 private boolean isSubtypeUncheckedInternal(Type t, Type s, Warner warn) {
317 if (t.tag == ARRAY && s.tag == ARRAY) {
318 if (((ArrayType)t).elemtype.tag <= lastBaseTag) {
319 return isSameType(elemtype(t), elemtype(s));
320 } else {
321 return isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
322 }
323 } else if (isSubtype(t, s)) {
324 return true;
325 }
326 else if (t.tag == TYPEVAR) {
327 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
328 }
329 else if (s.tag == UNDETVAR) {
330 UndetVar uv = (UndetVar)s;
331 if (uv.inst != null)
332 return isSubtypeUnchecked(t, uv.inst, warn);
333 }
334 else if (!s.isRaw()) {
335 Type t2 = asSuper(t, s.tsym);
336 if (t2 != null && t2.isRaw()) {
337 if (isReifiable(s))
338 warn.silentWarn(LintCategory.UNCHECKED);
339 else
340 warn.warn(LintCategory.UNCHECKED);
341 return true;
342 }
343 }
344 return false;
345 }
347 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
348 if (t.tag != ARRAY || isReifiable(t)) return;
349 ArrayType from = (ArrayType)t;
350 boolean shouldWarn = false;
351 switch (s.tag) {
352 case ARRAY:
353 ArrayType to = (ArrayType)s;
354 shouldWarn = from.isVarargs() &&
355 !to.isVarargs() &&
356 !isReifiable(from);
357 break;
358 case CLASS:
359 shouldWarn = from.isVarargs();
360 break;
361 }
362 if (shouldWarn) {
363 warn.warn(LintCategory.VARARGS);
364 }
365 }
367 /**
368 * Is t a subtype of s?<br>
369 * (not defined for Method and ForAll types)
370 */
371 final public boolean isSubtype(Type t, Type s) {
372 return isSubtype(t, s, true);
373 }
374 final public boolean isSubtypeNoCapture(Type t, Type s) {
375 return isSubtype(t, s, false);
376 }
377 public boolean isSubtype(Type t, Type s, boolean capture) {
378 if (t == s)
379 return true;
381 if (s.tag >= firstPartialTag)
382 return isSuperType(s, t);
384 if (s.isCompound()) {
385 for (Type s2 : interfaces(s).prepend(supertype(s))) {
386 if (!isSubtype(t, s2, capture))
387 return false;
388 }
389 return true;
390 }
392 Type lower = lowerBound(s);
393 if (s != lower)
394 return isSubtype(capture ? capture(t) : t, lower, false);
396 return isSubtype.visit(capture ? capture(t) : t, s);
397 }
398 // where
399 private TypeRelation isSubtype = new TypeRelation()
400 {
401 public Boolean visitType(Type t, Type s) {
402 switch (t.tag) {
403 case BYTE: case CHAR:
404 return (t.tag == s.tag ||
405 t.tag + 2 <= s.tag && s.tag <= DOUBLE);
406 case SHORT: case INT: case LONG: case FLOAT: case DOUBLE:
407 return t.tag <= s.tag && s.tag <= DOUBLE;
408 case BOOLEAN: case VOID:
409 return t.tag == s.tag;
410 case TYPEVAR:
411 return isSubtypeNoCapture(t.getUpperBound(), s);
412 case BOT:
413 return
414 s.tag == BOT || s.tag == CLASS ||
415 s.tag == ARRAY || s.tag == TYPEVAR;
416 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
417 case NONE:
418 return false;
419 default:
420 throw new AssertionError("isSubtype " + t.tag);
421 }
422 }
424 private Set<TypePair> cache = new HashSet<TypePair>();
426 private boolean containsTypeRecursive(Type t, Type s) {
427 TypePair pair = new TypePair(t, s);
428 if (cache.add(pair)) {
429 try {
430 return containsType(t.getTypeArguments(),
431 s.getTypeArguments());
432 } finally {
433 cache.remove(pair);
434 }
435 } else {
436 return containsType(t.getTypeArguments(),
437 rewriteSupers(s).getTypeArguments());
438 }
439 }
441 private Type rewriteSupers(Type t) {
442 if (!t.isParameterized())
443 return t;
444 ListBuffer<Type> from = lb();
445 ListBuffer<Type> to = lb();
446 adaptSelf(t, from, to);
447 if (from.isEmpty())
448 return t;
449 ListBuffer<Type> rewrite = lb();
450 boolean changed = false;
451 for (Type orig : to.toList()) {
452 Type s = rewriteSupers(orig);
453 if (s.isSuperBound() && !s.isExtendsBound()) {
454 s = new WildcardType(syms.objectType,
455 BoundKind.UNBOUND,
456 syms.boundClass);
457 changed = true;
458 } else if (s != orig) {
459 s = new WildcardType(upperBound(s),
460 BoundKind.EXTENDS,
461 syms.boundClass);
462 changed = true;
463 }
464 rewrite.append(s);
465 }
466 if (changed)
467 return subst(t.tsym.type, from.toList(), rewrite.toList());
468 else
469 return t;
470 }
472 @Override
473 public Boolean visitClassType(ClassType t, Type s) {
474 Type sup = asSuper(t, s.tsym);
475 return sup != null
476 && sup.tsym == s.tsym
477 // You're not allowed to write
478 // Vector<Object> vec = new Vector<String>();
479 // But with wildcards you can write
480 // Vector<? extends Object> vec = new Vector<String>();
481 // which means that subtype checking must be done
482 // here instead of same-type checking (via containsType).
483 && (!s.isParameterized() || containsTypeRecursive(s, sup))
484 && isSubtypeNoCapture(sup.getEnclosingType(),
485 s.getEnclosingType());
486 }
488 @Override
489 public Boolean visitArrayType(ArrayType t, Type s) {
490 if (s.tag == ARRAY) {
491 if (t.elemtype.tag <= lastBaseTag)
492 return isSameType(t.elemtype, elemtype(s));
493 else
494 return isSubtypeNoCapture(t.elemtype, elemtype(s));
495 }
497 if (s.tag == CLASS) {
498 Name sname = s.tsym.getQualifiedName();
499 return sname == names.java_lang_Object
500 || sname == names.java_lang_Cloneable
501 || sname == names.java_io_Serializable;
502 }
504 return false;
505 }
507 @Override
508 public Boolean visitUndetVar(UndetVar t, Type s) {
509 //todo: test against origin needed? or replace with substitution?
510 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN) {
511 return true;
512 } else if (s.tag == BOT) {
513 //if 's' is 'null' there's no instantiated type U for which
514 //U <: s (but 'null' itself, which is not a valid type)
515 return false;
516 }
518 if (t.inst != null)
519 return isSubtypeNoCapture(t.inst, s); // TODO: ", warn"?
521 t.hibounds = t.hibounds.prepend(s);
522 return true;
523 }
525 @Override
526 public Boolean visitErrorType(ErrorType t, Type s) {
527 return true;
528 }
529 };
531 /**
532 * Is t a subtype of every type in given list `ts'?<br>
533 * (not defined for Method and ForAll types)<br>
534 * Allows unchecked conversions.
535 */
536 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
537 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
538 if (!isSubtypeUnchecked(t, l.head, warn))
539 return false;
540 return true;
541 }
543 /**
544 * Are corresponding elements of ts subtypes of ss? If lists are
545 * of different length, return false.
546 */
547 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
548 while (ts.tail != null && ss.tail != null
549 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
550 isSubtype(ts.head, ss.head)) {
551 ts = ts.tail;
552 ss = ss.tail;
553 }
554 return ts.tail == null && ss.tail == null;
555 /*inlined: ts.isEmpty() && ss.isEmpty();*/
556 }
558 /**
559 * Are corresponding elements of ts subtypes of ss, allowing
560 * unchecked conversions? If lists are of different length,
561 * return false.
562 **/
563 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
564 while (ts.tail != null && ss.tail != null
565 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
566 isSubtypeUnchecked(ts.head, ss.head, warn)) {
567 ts = ts.tail;
568 ss = ss.tail;
569 }
570 return ts.tail == null && ss.tail == null;
571 /*inlined: ts.isEmpty() && ss.isEmpty();*/
572 }
573 // </editor-fold>
575 // <editor-fold defaultstate="collapsed" desc="isSuperType">
576 /**
577 * Is t a supertype of s?
578 */
579 public boolean isSuperType(Type t, Type s) {
580 switch (t.tag) {
581 case ERROR:
582 return true;
583 case UNDETVAR: {
584 UndetVar undet = (UndetVar)t;
585 if (t == s ||
586 undet.qtype == s ||
587 s.tag == ERROR ||
588 s.tag == BOT) return true;
589 if (undet.inst != null)
590 return isSubtype(s, undet.inst);
591 undet.lobounds = undet.lobounds.prepend(s);
592 return true;
593 }
594 default:
595 return isSubtype(s, t);
596 }
597 }
598 // </editor-fold>
600 // <editor-fold defaultstate="collapsed" desc="isSameType">
601 /**
602 * Are corresponding elements of the lists the same type? If
603 * lists are of different length, return false.
604 */
605 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
606 while (ts.tail != null && ss.tail != null
607 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
608 isSameType(ts.head, ss.head)) {
609 ts = ts.tail;
610 ss = ss.tail;
611 }
612 return ts.tail == null && ss.tail == null;
613 /*inlined: ts.isEmpty() && ss.isEmpty();*/
614 }
616 /**
617 * Is t the same type as s?
618 */
619 public boolean isSameType(Type t, Type s) {
620 return isSameType.visit(t, s);
621 }
622 // where
623 private TypeRelation isSameType = new TypeRelation() {
625 public Boolean visitType(Type t, Type s) {
626 if (t == s)
627 return true;
629 if (s.tag >= firstPartialTag)
630 return visit(s, t);
632 switch (t.tag) {
633 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
634 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
635 return t.tag == s.tag;
636 case TYPEVAR: {
637 if (s.tag == TYPEVAR) {
638 //type-substitution does not preserve type-var types
639 //check that type var symbols and bounds are indeed the same
640 return t.tsym == s.tsym &&
641 visit(t.getUpperBound(), s.getUpperBound());
642 }
643 else {
644 //special case for s == ? super X, where upper(s) = u
645 //check that u == t, where u has been set by Type.withTypeVar
646 return s.isSuperBound() &&
647 !s.isExtendsBound() &&
648 visit(t, upperBound(s));
649 }
650 }
651 default:
652 throw new AssertionError("isSameType " + t.tag);
653 }
654 }
656 @Override
657 public Boolean visitWildcardType(WildcardType t, Type s) {
658 if (s.tag >= firstPartialTag)
659 return visit(s, t);
660 else
661 return false;
662 }
664 @Override
665 public Boolean visitClassType(ClassType t, Type s) {
666 if (t == s)
667 return true;
669 if (s.tag >= firstPartialTag)
670 return visit(s, t);
672 if (s.isSuperBound() && !s.isExtendsBound())
673 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
675 if (t.isCompound() && s.isCompound()) {
676 if (!visit(supertype(t), supertype(s)))
677 return false;
679 HashSet<SingletonType> set = new HashSet<SingletonType>();
680 for (Type x : interfaces(t))
681 set.add(new SingletonType(x));
682 for (Type x : interfaces(s)) {
683 if (!set.remove(new SingletonType(x)))
684 return false;
685 }
686 return (set.isEmpty());
687 }
688 return t.tsym == s.tsym
689 && visit(t.getEnclosingType(), s.getEnclosingType())
690 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
691 }
693 @Override
694 public Boolean visitArrayType(ArrayType t, Type s) {
695 if (t == s)
696 return true;
698 if (s.tag >= firstPartialTag)
699 return visit(s, t);
701 return s.tag == ARRAY
702 && containsTypeEquivalent(t.elemtype, elemtype(s));
703 }
705 @Override
706 public Boolean visitMethodType(MethodType t, Type s) {
707 // isSameType for methods does not take thrown
708 // exceptions into account!
709 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
710 }
712 @Override
713 public Boolean visitPackageType(PackageType t, Type s) {
714 return t == s;
715 }
717 @Override
718 public Boolean visitForAll(ForAll t, Type s) {
719 if (s.tag != FORALL)
720 return false;
722 ForAll forAll = (ForAll)s;
723 return hasSameBounds(t, forAll)
724 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
725 }
727 @Override
728 public Boolean visitUndetVar(UndetVar t, Type s) {
729 if (s.tag == WILDCARD)
730 // FIXME, this might be leftovers from before capture conversion
731 return false;
733 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
734 return true;
736 if (t.inst != null)
737 return visit(t.inst, s);
739 t.inst = fromUnknownFun.apply(s);
740 for (List<Type> l = t.lobounds; l.nonEmpty(); l = l.tail) {
741 if (!isSubtype(l.head, t.inst))
742 return false;
743 }
744 for (List<Type> l = t.hibounds; l.nonEmpty(); l = l.tail) {
745 if (!isSubtype(t.inst, l.head))
746 return false;
747 }
748 return true;
749 }
751 @Override
752 public Boolean visitErrorType(ErrorType t, Type s) {
753 return true;
754 }
755 };
756 // </editor-fold>
758 // <editor-fold defaultstate="collapsed" desc="fromUnknownFun">
759 /**
760 * A mapping that turns all unknown types in this type to fresh
761 * unknown variables.
762 */
763 public Mapping fromUnknownFun = new Mapping("fromUnknownFun") {
764 public Type apply(Type t) {
765 if (t.tag == UNKNOWN) return new UndetVar(t);
766 else return t.map(this);
767 }
768 };
769 // </editor-fold>
771 // <editor-fold defaultstate="collapsed" desc="Contains Type">
772 public boolean containedBy(Type t, Type s) {
773 switch (t.tag) {
774 case UNDETVAR:
775 if (s.tag == WILDCARD) {
776 UndetVar undetvar = (UndetVar)t;
777 WildcardType wt = (WildcardType)s;
778 switch(wt.kind) {
779 case UNBOUND: //similar to ? extends Object
780 case EXTENDS: {
781 Type bound = upperBound(s);
782 // We should check the new upper bound against any of the
783 // undetvar's lower bounds.
784 for (Type t2 : undetvar.lobounds) {
785 if (!isSubtype(t2, bound))
786 return false;
787 }
788 undetvar.hibounds = undetvar.hibounds.prepend(bound);
789 break;
790 }
791 case SUPER: {
792 Type bound = lowerBound(s);
793 // We should check the new lower bound against any of the
794 // undetvar's lower bounds.
795 for (Type t2 : undetvar.hibounds) {
796 if (!isSubtype(bound, t2))
797 return false;
798 }
799 undetvar.lobounds = undetvar.lobounds.prepend(bound);
800 break;
801 }
802 }
803 return true;
804 } else {
805 return isSameType(t, s);
806 }
807 case ERROR:
808 return true;
809 default:
810 return containsType(s, t);
811 }
812 }
814 boolean containsType(List<Type> ts, List<Type> ss) {
815 while (ts.nonEmpty() && ss.nonEmpty()
816 && containsType(ts.head, ss.head)) {
817 ts = ts.tail;
818 ss = ss.tail;
819 }
820 return ts.isEmpty() && ss.isEmpty();
821 }
823 /**
824 * Check if t contains s.
825 *
826 * <p>T contains S if:
827 *
828 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
829 *
830 * <p>This relation is only used by ClassType.isSubtype(), that
831 * is,
832 *
833 * <p>{@code C<S> <: C<T> if T contains S.}
834 *
835 * <p>Because of F-bounds, this relation can lead to infinite
836 * recursion. Thus we must somehow break that recursion. Notice
837 * that containsType() is only called from ClassType.isSubtype().
838 * Since the arguments have already been checked against their
839 * bounds, we know:
840 *
841 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
842 *
843 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
844 *
845 * @param t a type
846 * @param s a type
847 */
848 public boolean containsType(Type t, Type s) {
849 return containsType.visit(t, s);
850 }
851 // where
852 private TypeRelation containsType = new TypeRelation() {
854 private Type U(Type t) {
855 while (t.tag == WILDCARD) {
856 WildcardType w = (WildcardType)t;
857 if (w.isSuperBound())
858 return w.bound == null ? syms.objectType : w.bound.bound;
859 else
860 t = w.type;
861 }
862 return t;
863 }
865 private Type L(Type t) {
866 while (t.tag == WILDCARD) {
867 WildcardType w = (WildcardType)t;
868 if (w.isExtendsBound())
869 return syms.botType;
870 else
871 t = w.type;
872 }
873 return t;
874 }
876 public Boolean visitType(Type t, Type s) {
877 if (s.tag >= firstPartialTag)
878 return containedBy(s, t);
879 else
880 return isSameType(t, s);
881 }
883 // void debugContainsType(WildcardType t, Type s) {
884 // System.err.println();
885 // System.err.format(" does %s contain %s?%n", t, s);
886 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
887 // upperBound(s), s, t, U(t),
888 // t.isSuperBound()
889 // || isSubtypeNoCapture(upperBound(s), U(t)));
890 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
891 // L(t), t, s, lowerBound(s),
892 // t.isExtendsBound()
893 // || isSubtypeNoCapture(L(t), lowerBound(s)));
894 // System.err.println();
895 // }
897 @Override
898 public Boolean visitWildcardType(WildcardType t, Type s) {
899 if (s.tag >= firstPartialTag)
900 return containedBy(s, t);
901 else {
902 // debugContainsType(t, s);
903 return isSameWildcard(t, s)
904 || isCaptureOf(s, t)
905 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
906 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
907 }
908 }
910 @Override
911 public Boolean visitUndetVar(UndetVar t, Type s) {
912 if (s.tag != WILDCARD)
913 return isSameType(t, s);
914 else
915 return false;
916 }
918 @Override
919 public Boolean visitErrorType(ErrorType t, Type s) {
920 return true;
921 }
922 };
924 public boolean isCaptureOf(Type s, WildcardType t) {
925 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
926 return false;
927 return isSameWildcard(t, ((CapturedType)s).wildcard);
928 }
930 public boolean isSameWildcard(WildcardType t, Type s) {
931 if (s.tag != WILDCARD)
932 return false;
933 WildcardType w = (WildcardType)s;
934 return w.kind == t.kind && w.type == t.type;
935 }
937 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
938 while (ts.nonEmpty() && ss.nonEmpty()
939 && containsTypeEquivalent(ts.head, ss.head)) {
940 ts = ts.tail;
941 ss = ss.tail;
942 }
943 return ts.isEmpty() && ss.isEmpty();
944 }
945 // </editor-fold>
947 // <editor-fold defaultstate="collapsed" desc="isCastable">
948 public boolean isCastable(Type t, Type s) {
949 return isCastable(t, s, Warner.noWarnings);
950 }
952 /**
953 * Is t is castable to s?<br>
954 * s is assumed to be an erased type.<br>
955 * (not defined for Method and ForAll types).
956 */
957 public boolean isCastable(Type t, Type s, Warner warn) {
958 if (t == s)
959 return true;
961 if (t.isPrimitive() != s.isPrimitive())
962 return allowBoxing && (
963 isConvertible(t, s, warn)
964 || (allowObjectToPrimitiveCast &&
965 s.isPrimitive() &&
966 isSubtype(boxedClass(s).type, t)));
967 if (warn != warnStack.head) {
968 try {
969 warnStack = warnStack.prepend(warn);
970 checkUnsafeVarargsConversion(t, s, warn);
971 return isCastable.visit(t,s);
972 } finally {
973 warnStack = warnStack.tail;
974 }
975 } else {
976 return isCastable.visit(t,s);
977 }
978 }
979 // where
980 private TypeRelation isCastable = new TypeRelation() {
982 public Boolean visitType(Type t, Type s) {
983 if (s.tag == ERROR)
984 return true;
986 switch (t.tag) {
987 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
988 case DOUBLE:
989 return s.tag <= DOUBLE;
990 case BOOLEAN:
991 return s.tag == BOOLEAN;
992 case VOID:
993 return false;
994 case BOT:
995 return isSubtype(t, s);
996 default:
997 throw new AssertionError();
998 }
999 }
1001 @Override
1002 public Boolean visitWildcardType(WildcardType t, Type s) {
1003 return isCastable(upperBound(t), s, warnStack.head);
1004 }
1006 @Override
1007 public Boolean visitClassType(ClassType t, Type s) {
1008 if (s.tag == ERROR || s.tag == BOT)
1009 return true;
1011 if (s.tag == TYPEVAR) {
1012 if (isCastable(t, s.getUpperBound(), Warner.noWarnings)) {
1013 warnStack.head.warn(LintCategory.UNCHECKED);
1014 return true;
1015 } else {
1016 return false;
1017 }
1018 }
1020 if (t.isCompound()) {
1021 Warner oldWarner = warnStack.head;
1022 warnStack.head = Warner.noWarnings;
1023 if (!visit(supertype(t), s))
1024 return false;
1025 for (Type intf : interfaces(t)) {
1026 if (!visit(intf, s))
1027 return false;
1028 }
1029 if (warnStack.head.hasLint(LintCategory.UNCHECKED))
1030 oldWarner.warn(LintCategory.UNCHECKED);
1031 return true;
1032 }
1034 if (s.isCompound()) {
1035 // call recursively to reuse the above code
1036 return visitClassType((ClassType)s, t);
1037 }
1039 if (s.tag == CLASS || s.tag == ARRAY) {
1040 boolean upcast;
1041 if ((upcast = isSubtype(erasure(t), erasure(s)))
1042 || isSubtype(erasure(s), erasure(t))) {
1043 if (!upcast && s.tag == ARRAY) {
1044 if (!isReifiable(s))
1045 warnStack.head.warn(LintCategory.UNCHECKED);
1046 return true;
1047 } else if (s.isRaw()) {
1048 return true;
1049 } else if (t.isRaw()) {
1050 if (!isUnbounded(s))
1051 warnStack.head.warn(LintCategory.UNCHECKED);
1052 return true;
1053 }
1054 // Assume |a| <: |b|
1055 final Type a = upcast ? t : s;
1056 final Type b = upcast ? s : t;
1057 final boolean HIGH = true;
1058 final boolean LOW = false;
1059 final boolean DONT_REWRITE_TYPEVARS = false;
1060 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1061 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1062 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1063 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1064 Type lowSub = asSub(bLow, aLow.tsym);
1065 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1066 if (highSub == null) {
1067 final boolean REWRITE_TYPEVARS = true;
1068 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1069 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1070 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1071 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1072 lowSub = asSub(bLow, aLow.tsym);
1073 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1074 }
1075 if (highSub != null) {
1076 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1077 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1078 }
1079 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1080 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1081 && !disjointTypes(aLow.allparams(), highSub.allparams())
1082 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1083 if (upcast ? giveWarning(a, b) :
1084 giveWarning(b, a))
1085 warnStack.head.warn(LintCategory.UNCHECKED);
1086 return true;
1087 }
1088 }
1089 if (isReifiable(s))
1090 return isSubtypeUnchecked(a, b);
1091 else
1092 return isSubtypeUnchecked(a, b, warnStack.head);
1093 }
1095 // Sidecast
1096 if (s.tag == CLASS) {
1097 if ((s.tsym.flags() & INTERFACE) != 0) {
1098 return ((t.tsym.flags() & FINAL) == 0)
1099 ? sideCast(t, s, warnStack.head)
1100 : sideCastFinal(t, s, warnStack.head);
1101 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1102 return ((s.tsym.flags() & FINAL) == 0)
1103 ? sideCast(t, s, warnStack.head)
1104 : sideCastFinal(t, s, warnStack.head);
1105 } else {
1106 // unrelated class types
1107 return false;
1108 }
1109 }
1110 }
1111 return false;
1112 }
1114 @Override
1115 public Boolean visitArrayType(ArrayType t, Type s) {
1116 switch (s.tag) {
1117 case ERROR:
1118 case BOT:
1119 return true;
1120 case TYPEVAR:
1121 if (isCastable(s, t, Warner.noWarnings)) {
1122 warnStack.head.warn(LintCategory.UNCHECKED);
1123 return true;
1124 } else {
1125 return false;
1126 }
1127 case CLASS:
1128 return isSubtype(t, s);
1129 case ARRAY:
1130 if (elemtype(t).tag <= lastBaseTag ||
1131 elemtype(s).tag <= lastBaseTag) {
1132 return elemtype(t).tag == elemtype(s).tag;
1133 } else {
1134 return visit(elemtype(t), elemtype(s));
1135 }
1136 default:
1137 return false;
1138 }
1139 }
1141 @Override
1142 public Boolean visitTypeVar(TypeVar t, Type s) {
1143 switch (s.tag) {
1144 case ERROR:
1145 case BOT:
1146 return true;
1147 case TYPEVAR:
1148 if (isSubtype(t, s)) {
1149 return true;
1150 } else if (isCastable(t.bound, s, Warner.noWarnings)) {
1151 warnStack.head.warn(LintCategory.UNCHECKED);
1152 return true;
1153 } else {
1154 return false;
1155 }
1156 default:
1157 return isCastable(t.bound, s, warnStack.head);
1158 }
1159 }
1161 @Override
1162 public Boolean visitErrorType(ErrorType t, Type s) {
1163 return true;
1164 }
1165 };
1166 // </editor-fold>
1168 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1169 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1170 while (ts.tail != null && ss.tail != null) {
1171 if (disjointType(ts.head, ss.head)) return true;
1172 ts = ts.tail;
1173 ss = ss.tail;
1174 }
1175 return false;
1176 }
1178 /**
1179 * Two types or wildcards are considered disjoint if it can be
1180 * proven that no type can be contained in both. It is
1181 * conservative in that it is allowed to say that two types are
1182 * not disjoint, even though they actually are.
1183 *
1184 * The type C<X> is castable to C<Y> exactly if X and Y are not
1185 * disjoint.
1186 */
1187 public boolean disjointType(Type t, Type s) {
1188 return disjointType.visit(t, s);
1189 }
1190 // where
1191 private TypeRelation disjointType = new TypeRelation() {
1193 private Set<TypePair> cache = new HashSet<TypePair>();
1195 public Boolean visitType(Type t, Type s) {
1196 if (s.tag == WILDCARD)
1197 return visit(s, t);
1198 else
1199 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1200 }
1202 private boolean isCastableRecursive(Type t, Type s) {
1203 TypePair pair = new TypePair(t, s);
1204 if (cache.add(pair)) {
1205 try {
1206 return Types.this.isCastable(t, s);
1207 } finally {
1208 cache.remove(pair);
1209 }
1210 } else {
1211 return true;
1212 }
1213 }
1215 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1216 TypePair pair = new TypePair(t, s);
1217 if (cache.add(pair)) {
1218 try {
1219 return Types.this.notSoftSubtype(t, s);
1220 } finally {
1221 cache.remove(pair);
1222 }
1223 } else {
1224 return false;
1225 }
1226 }
1228 @Override
1229 public Boolean visitWildcardType(WildcardType t, Type s) {
1230 if (t.isUnbound())
1231 return false;
1233 if (s.tag != WILDCARD) {
1234 if (t.isExtendsBound())
1235 return notSoftSubtypeRecursive(s, t.type);
1236 else // isSuperBound()
1237 return notSoftSubtypeRecursive(t.type, s);
1238 }
1240 if (s.isUnbound())
1241 return false;
1243 if (t.isExtendsBound()) {
1244 if (s.isExtendsBound())
1245 return !isCastableRecursive(t.type, upperBound(s));
1246 else if (s.isSuperBound())
1247 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1248 } else if (t.isSuperBound()) {
1249 if (s.isExtendsBound())
1250 return notSoftSubtypeRecursive(t.type, upperBound(s));
1251 }
1252 return false;
1253 }
1254 };
1255 // </editor-fold>
1257 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1258 /**
1259 * Returns the lower bounds of the formals of a method.
1260 */
1261 public List<Type> lowerBoundArgtypes(Type t) {
1262 return map(t.getParameterTypes(), lowerBoundMapping);
1263 }
1264 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1265 public Type apply(Type t) {
1266 return lowerBound(t);
1267 }
1268 };
1269 // </editor-fold>
1271 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1272 /**
1273 * This relation answers the question: is impossible that
1274 * something of type `t' can be a subtype of `s'? This is
1275 * different from the question "is `t' not a subtype of `s'?"
1276 * when type variables are involved: Integer is not a subtype of T
1277 * where <T extends Number> but it is not true that Integer cannot
1278 * possibly be a subtype of T.
1279 */
1280 public boolean notSoftSubtype(Type t, Type s) {
1281 if (t == s) return false;
1282 if (t.tag == TYPEVAR) {
1283 TypeVar tv = (TypeVar) t;
1284 return !isCastable(tv.bound,
1285 relaxBound(s),
1286 Warner.noWarnings);
1287 }
1288 if (s.tag != WILDCARD)
1289 s = upperBound(s);
1291 return !isSubtype(t, relaxBound(s));
1292 }
1294 private Type relaxBound(Type t) {
1295 if (t.tag == TYPEVAR) {
1296 while (t.tag == TYPEVAR)
1297 t = t.getUpperBound();
1298 t = rewriteQuantifiers(t, true, true);
1299 }
1300 return t;
1301 }
1302 // </editor-fold>
1304 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1305 public boolean isReifiable(Type t) {
1306 return isReifiable.visit(t);
1307 }
1308 // where
1309 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1311 public Boolean visitType(Type t, Void ignored) {
1312 return true;
1313 }
1315 @Override
1316 public Boolean visitClassType(ClassType t, Void ignored) {
1317 if (t.isCompound())
1318 return false;
1319 else {
1320 if (!t.isParameterized())
1321 return true;
1323 for (Type param : t.allparams()) {
1324 if (!param.isUnbound())
1325 return false;
1326 }
1327 return true;
1328 }
1329 }
1331 @Override
1332 public Boolean visitArrayType(ArrayType t, Void ignored) {
1333 return visit(t.elemtype);
1334 }
1336 @Override
1337 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1338 return false;
1339 }
1340 };
1341 // </editor-fold>
1343 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1344 public boolean isArray(Type t) {
1345 while (t.tag == WILDCARD)
1346 t = upperBound(t);
1347 return t.tag == ARRAY;
1348 }
1350 /**
1351 * The element type of an array.
1352 */
1353 public Type elemtype(Type t) {
1354 switch (t.tag) {
1355 case WILDCARD:
1356 return elemtype(upperBound(t));
1357 case ARRAY:
1358 return ((ArrayType)t).elemtype;
1359 case FORALL:
1360 return elemtype(((ForAll)t).qtype);
1361 case ERROR:
1362 return t;
1363 default:
1364 return null;
1365 }
1366 }
1368 public Type elemtypeOrType(Type t) {
1369 Type elemtype = elemtype(t);
1370 return elemtype != null ?
1371 elemtype :
1372 t;
1373 }
1375 /**
1376 * Mapping to take element type of an arraytype
1377 */
1378 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1379 public Type apply(Type t) { return elemtype(t); }
1380 };
1382 /**
1383 * The number of dimensions of an array type.
1384 */
1385 public int dimensions(Type t) {
1386 int result = 0;
1387 while (t.tag == ARRAY) {
1388 result++;
1389 t = elemtype(t);
1390 }
1391 return result;
1392 }
1393 // </editor-fold>
1395 // <editor-fold defaultstate="collapsed" desc="asSuper">
1396 /**
1397 * Return the (most specific) base type of t that starts with the
1398 * given symbol. If none exists, return null.
1399 *
1400 * @param t a type
1401 * @param sym a symbol
1402 */
1403 public Type asSuper(Type t, Symbol sym) {
1404 return asSuper.visit(t, sym);
1405 }
1406 // where
1407 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1409 public Type visitType(Type t, Symbol sym) {
1410 return null;
1411 }
1413 @Override
1414 public Type visitClassType(ClassType t, Symbol sym) {
1415 if (t.tsym == sym)
1416 return t;
1418 Type st = supertype(t);
1419 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1420 Type x = asSuper(st, sym);
1421 if (x != null)
1422 return x;
1423 }
1424 if ((sym.flags() & INTERFACE) != 0) {
1425 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1426 Type x = asSuper(l.head, sym);
1427 if (x != null)
1428 return x;
1429 }
1430 }
1431 return null;
1432 }
1434 @Override
1435 public Type visitArrayType(ArrayType t, Symbol sym) {
1436 return isSubtype(t, sym.type) ? sym.type : null;
1437 }
1439 @Override
1440 public Type visitTypeVar(TypeVar t, Symbol sym) {
1441 if (t.tsym == sym)
1442 return t;
1443 else
1444 return asSuper(t.bound, sym);
1445 }
1447 @Override
1448 public Type visitErrorType(ErrorType t, Symbol sym) {
1449 return t;
1450 }
1451 };
1453 /**
1454 * Return the base type of t or any of its outer types that starts
1455 * with the given symbol. If none exists, return null.
1456 *
1457 * @param t a type
1458 * @param sym a symbol
1459 */
1460 public Type asOuterSuper(Type t, Symbol sym) {
1461 switch (t.tag) {
1462 case CLASS:
1463 do {
1464 Type s = asSuper(t, sym);
1465 if (s != null) return s;
1466 t = t.getEnclosingType();
1467 } while (t.tag == CLASS);
1468 return null;
1469 case ARRAY:
1470 return isSubtype(t, sym.type) ? sym.type : null;
1471 case TYPEVAR:
1472 return asSuper(t, sym);
1473 case ERROR:
1474 return t;
1475 default:
1476 return null;
1477 }
1478 }
1480 /**
1481 * Return the base type of t or any of its enclosing types that
1482 * starts with the given symbol. If none exists, return null.
1483 *
1484 * @param t a type
1485 * @param sym a symbol
1486 */
1487 public Type asEnclosingSuper(Type t, Symbol sym) {
1488 switch (t.tag) {
1489 case CLASS:
1490 do {
1491 Type s = asSuper(t, sym);
1492 if (s != null) return s;
1493 Type outer = t.getEnclosingType();
1494 t = (outer.tag == CLASS) ? outer :
1495 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1496 Type.noType;
1497 } while (t.tag == CLASS);
1498 return null;
1499 case ARRAY:
1500 return isSubtype(t, sym.type) ? sym.type : null;
1501 case TYPEVAR:
1502 return asSuper(t, sym);
1503 case ERROR:
1504 return t;
1505 default:
1506 return null;
1507 }
1508 }
1509 // </editor-fold>
1511 // <editor-fold defaultstate="collapsed" desc="memberType">
1512 /**
1513 * The type of given symbol, seen as a member of t.
1514 *
1515 * @param t a type
1516 * @param sym a symbol
1517 */
1518 public Type memberType(Type t, Symbol sym) {
1519 return (sym.flags() & STATIC) != 0
1520 ? sym.type
1521 : memberType.visit(t, sym);
1522 }
1523 // where
1524 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1526 public Type visitType(Type t, Symbol sym) {
1527 return sym.type;
1528 }
1530 @Override
1531 public Type visitWildcardType(WildcardType t, Symbol sym) {
1532 return memberType(upperBound(t), sym);
1533 }
1535 @Override
1536 public Type visitClassType(ClassType t, Symbol sym) {
1537 Symbol owner = sym.owner;
1538 long flags = sym.flags();
1539 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1540 Type base = asOuterSuper(t, owner);
1541 //if t is an intersection type T = CT & I1 & I2 ... & In
1542 //its supertypes CT, I1, ... In might contain wildcards
1543 //so we need to go through capture conversion
1544 base = t.isCompound() ? capture(base) : base;
1545 if (base != null) {
1546 List<Type> ownerParams = owner.type.allparams();
1547 List<Type> baseParams = base.allparams();
1548 if (ownerParams.nonEmpty()) {
1549 if (baseParams.isEmpty()) {
1550 // then base is a raw type
1551 return erasure(sym.type);
1552 } else {
1553 return subst(sym.type, ownerParams, baseParams);
1554 }
1555 }
1556 }
1557 }
1558 return sym.type;
1559 }
1561 @Override
1562 public Type visitTypeVar(TypeVar t, Symbol sym) {
1563 return memberType(t.bound, sym);
1564 }
1566 @Override
1567 public Type visitErrorType(ErrorType t, Symbol sym) {
1568 return t;
1569 }
1570 };
1571 // </editor-fold>
1573 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1574 public boolean isAssignable(Type t, Type s) {
1575 return isAssignable(t, s, Warner.noWarnings);
1576 }
1578 /**
1579 * Is t assignable to s?<br>
1580 * Equivalent to subtype except for constant values and raw
1581 * types.<br>
1582 * (not defined for Method and ForAll types)
1583 */
1584 public boolean isAssignable(Type t, Type s, Warner warn) {
1585 if (t.tag == ERROR)
1586 return true;
1587 if (t.tag <= INT && t.constValue() != null) {
1588 int value = ((Number)t.constValue()).intValue();
1589 switch (s.tag) {
1590 case BYTE:
1591 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1592 return true;
1593 break;
1594 case CHAR:
1595 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1596 return true;
1597 break;
1598 case SHORT:
1599 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1600 return true;
1601 break;
1602 case INT:
1603 return true;
1604 case CLASS:
1605 switch (unboxedType(s).tag) {
1606 case BYTE:
1607 case CHAR:
1608 case SHORT:
1609 return isAssignable(t, unboxedType(s), warn);
1610 }
1611 break;
1612 }
1613 }
1614 return isConvertible(t, s, warn);
1615 }
1616 // </editor-fold>
1618 // <editor-fold defaultstate="collapsed" desc="erasure">
1619 /**
1620 * The erasure of t {@code |t|} -- the type that results when all
1621 * type parameters in t are deleted.
1622 */
1623 public Type erasure(Type t) {
1624 return erasure(t, false);
1625 }
1626 //where
1627 private Type erasure(Type t, boolean recurse) {
1628 if (t.tag <= lastBaseTag)
1629 return t; /* fast special case */
1630 else
1631 return erasure.visit(t, recurse);
1632 }
1633 // where
1634 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
1635 public Type visitType(Type t, Boolean recurse) {
1636 if (t.tag <= lastBaseTag)
1637 return t; /*fast special case*/
1638 else
1639 return t.map(recurse ? erasureRecFun : erasureFun);
1640 }
1642 @Override
1643 public Type visitWildcardType(WildcardType t, Boolean recurse) {
1644 return erasure(upperBound(t), recurse);
1645 }
1647 @Override
1648 public Type visitClassType(ClassType t, Boolean recurse) {
1649 Type erased = t.tsym.erasure(Types.this);
1650 if (recurse) {
1651 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
1652 }
1653 return erased;
1654 }
1656 @Override
1657 public Type visitTypeVar(TypeVar t, Boolean recurse) {
1658 return erasure(t.bound, recurse);
1659 }
1661 @Override
1662 public Type visitErrorType(ErrorType t, Boolean recurse) {
1663 return t;
1664 }
1665 };
1667 private Mapping erasureFun = new Mapping ("erasure") {
1668 public Type apply(Type t) { return erasure(t); }
1669 };
1671 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
1672 public Type apply(Type t) { return erasureRecursive(t); }
1673 };
1675 public List<Type> erasure(List<Type> ts) {
1676 return Type.map(ts, erasureFun);
1677 }
1679 public Type erasureRecursive(Type t) {
1680 return erasure(t, true);
1681 }
1683 public List<Type> erasureRecursive(List<Type> ts) {
1684 return Type.map(ts, erasureRecFun);
1685 }
1686 // </editor-fold>
1688 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
1689 /**
1690 * Make a compound type from non-empty list of types
1691 *
1692 * @param bounds the types from which the compound type is formed
1693 * @param supertype is objectType if all bounds are interfaces,
1694 * null otherwise.
1695 */
1696 public Type makeCompoundType(List<Type> bounds,
1697 Type supertype) {
1698 ClassSymbol bc =
1699 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
1700 Type.moreInfo
1701 ? names.fromString(bounds.toString())
1702 : names.empty,
1703 syms.noSymbol);
1704 if (bounds.head.tag == TYPEVAR)
1705 // error condition, recover
1706 bc.erasure_field = syms.objectType;
1707 else
1708 bc.erasure_field = erasure(bounds.head);
1709 bc.members_field = new Scope(bc);
1710 ClassType bt = (ClassType)bc.type;
1711 bt.allparams_field = List.nil();
1712 if (supertype != null) {
1713 bt.supertype_field = supertype;
1714 bt.interfaces_field = bounds;
1715 } else {
1716 bt.supertype_field = bounds.head;
1717 bt.interfaces_field = bounds.tail;
1718 }
1719 Assert.check(bt.supertype_field.tsym.completer != null
1720 || !bt.supertype_field.isInterface(),
1721 bt.supertype_field);
1722 return bt;
1723 }
1725 /**
1726 * Same as {@link #makeCompoundType(List,Type)}, except that the
1727 * second parameter is computed directly. Note that this might
1728 * cause a symbol completion. Hence, this version of
1729 * makeCompoundType may not be called during a classfile read.
1730 */
1731 public Type makeCompoundType(List<Type> bounds) {
1732 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1733 supertype(bounds.head) : null;
1734 return makeCompoundType(bounds, supertype);
1735 }
1737 /**
1738 * A convenience wrapper for {@link #makeCompoundType(List)}; the
1739 * arguments are converted to a list and passed to the other
1740 * method. Note that this might cause a symbol completion.
1741 * Hence, this version of makeCompoundType may not be called
1742 * during a classfile read.
1743 */
1744 public Type makeCompoundType(Type bound1, Type bound2) {
1745 return makeCompoundType(List.of(bound1, bound2));
1746 }
1747 // </editor-fold>
1749 // <editor-fold defaultstate="collapsed" desc="supertype">
1750 public Type supertype(Type t) {
1751 return supertype.visit(t);
1752 }
1753 // where
1754 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
1756 public Type visitType(Type t, Void ignored) {
1757 // A note on wildcards: there is no good way to
1758 // determine a supertype for a super bounded wildcard.
1759 return null;
1760 }
1762 @Override
1763 public Type visitClassType(ClassType t, Void ignored) {
1764 if (t.supertype_field == null) {
1765 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
1766 // An interface has no superclass; its supertype is Object.
1767 if (t.isInterface())
1768 supertype = ((ClassType)t.tsym.type).supertype_field;
1769 if (t.supertype_field == null) {
1770 List<Type> actuals = classBound(t).allparams();
1771 List<Type> formals = t.tsym.type.allparams();
1772 if (t.hasErasedSupertypes()) {
1773 t.supertype_field = erasureRecursive(supertype);
1774 } else if (formals.nonEmpty()) {
1775 t.supertype_field = subst(supertype, formals, actuals);
1776 }
1777 else {
1778 t.supertype_field = supertype;
1779 }
1780 }
1781 }
1782 return t.supertype_field;
1783 }
1785 /**
1786 * The supertype is always a class type. If the type
1787 * variable's bounds start with a class type, this is also
1788 * the supertype. Otherwise, the supertype is
1789 * java.lang.Object.
1790 */
1791 @Override
1792 public Type visitTypeVar(TypeVar t, Void ignored) {
1793 if (t.bound.tag == TYPEVAR ||
1794 (!t.bound.isCompound() && !t.bound.isInterface())) {
1795 return t.bound;
1796 } else {
1797 return supertype(t.bound);
1798 }
1799 }
1801 @Override
1802 public Type visitArrayType(ArrayType t, Void ignored) {
1803 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
1804 return arraySuperType();
1805 else
1806 return new ArrayType(supertype(t.elemtype), t.tsym);
1807 }
1809 @Override
1810 public Type visitErrorType(ErrorType t, Void ignored) {
1811 return t;
1812 }
1813 };
1814 // </editor-fold>
1816 // <editor-fold defaultstate="collapsed" desc="interfaces">
1817 /**
1818 * Return the interfaces implemented by this class.
1819 */
1820 public List<Type> interfaces(Type t) {
1821 return interfaces.visit(t);
1822 }
1823 // where
1824 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
1826 public List<Type> visitType(Type t, Void ignored) {
1827 return List.nil();
1828 }
1830 @Override
1831 public List<Type> visitClassType(ClassType t, Void ignored) {
1832 if (t.interfaces_field == null) {
1833 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
1834 if (t.interfaces_field == null) {
1835 // If t.interfaces_field is null, then t must
1836 // be a parameterized type (not to be confused
1837 // with a generic type declaration).
1838 // Terminology:
1839 // Parameterized type: List<String>
1840 // Generic type declaration: class List<E> { ... }
1841 // So t corresponds to List<String> and
1842 // t.tsym.type corresponds to List<E>.
1843 // The reason t must be parameterized type is
1844 // that completion will happen as a side
1845 // effect of calling
1846 // ClassSymbol.getInterfaces. Since
1847 // t.interfaces_field is null after
1848 // completion, we can assume that t is not the
1849 // type of a class/interface declaration.
1850 Assert.check(t != t.tsym.type, t);
1851 List<Type> actuals = t.allparams();
1852 List<Type> formals = t.tsym.type.allparams();
1853 if (t.hasErasedSupertypes()) {
1854 t.interfaces_field = erasureRecursive(interfaces);
1855 } else if (formals.nonEmpty()) {
1856 t.interfaces_field =
1857 upperBounds(subst(interfaces, formals, actuals));
1858 }
1859 else {
1860 t.interfaces_field = interfaces;
1861 }
1862 }
1863 }
1864 return t.interfaces_field;
1865 }
1867 @Override
1868 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
1869 if (t.bound.isCompound())
1870 return interfaces(t.bound);
1872 if (t.bound.isInterface())
1873 return List.of(t.bound);
1875 return List.nil();
1876 }
1877 };
1878 // </editor-fold>
1880 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
1881 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
1883 public boolean isDerivedRaw(Type t) {
1884 Boolean result = isDerivedRawCache.get(t);
1885 if (result == null) {
1886 result = isDerivedRawInternal(t);
1887 isDerivedRawCache.put(t, result);
1888 }
1889 return result;
1890 }
1892 public boolean isDerivedRawInternal(Type t) {
1893 if (t.isErroneous())
1894 return false;
1895 return
1896 t.isRaw() ||
1897 supertype(t) != null && isDerivedRaw(supertype(t)) ||
1898 isDerivedRaw(interfaces(t));
1899 }
1901 public boolean isDerivedRaw(List<Type> ts) {
1902 List<Type> l = ts;
1903 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
1904 return l.nonEmpty();
1905 }
1906 // </editor-fold>
1908 // <editor-fold defaultstate="collapsed" desc="setBounds">
1909 /**
1910 * Set the bounds field of the given type variable to reflect a
1911 * (possibly multiple) list of bounds.
1912 * @param t a type variable
1913 * @param bounds the bounds, must be nonempty
1914 * @param supertype is objectType if all bounds are interfaces,
1915 * null otherwise.
1916 */
1917 public void setBounds(TypeVar t, List<Type> bounds, Type supertype) {
1918 if (bounds.tail.isEmpty())
1919 t.bound = bounds.head;
1920 else
1921 t.bound = makeCompoundType(bounds, supertype);
1922 t.rank_field = -1;
1923 }
1925 /**
1926 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
1927 * third parameter is computed directly, as follows: if all
1928 * all bounds are interface types, the computed supertype is Object,
1929 * otherwise the supertype is simply left null (in this case, the supertype
1930 * is assumed to be the head of the bound list passed as second argument).
1931 * Note that this check might cause a symbol completion. Hence, this version of
1932 * setBounds may not be called during a classfile read.
1933 */
1934 public void setBounds(TypeVar t, List<Type> bounds) {
1935 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1936 syms.objectType : null;
1937 setBounds(t, bounds, supertype);
1938 t.rank_field = -1;
1939 }
1940 // </editor-fold>
1942 // <editor-fold defaultstate="collapsed" desc="getBounds">
1943 /**
1944 * Return list of bounds of the given type variable.
1945 */
1946 public List<Type> getBounds(TypeVar t) {
1947 if (t.bound.isErroneous() || !t.bound.isCompound())
1948 return List.of(t.bound);
1949 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
1950 return interfaces(t).prepend(supertype(t));
1951 else
1952 // No superclass was given in bounds.
1953 // In this case, supertype is Object, erasure is first interface.
1954 return interfaces(t);
1955 }
1956 // </editor-fold>
1958 // <editor-fold defaultstate="collapsed" desc="classBound">
1959 /**
1960 * If the given type is a (possibly selected) type variable,
1961 * return the bounding class of this type, otherwise return the
1962 * type itself.
1963 */
1964 public Type classBound(Type t) {
1965 return classBound.visit(t);
1966 }
1967 // where
1968 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
1970 public Type visitType(Type t, Void ignored) {
1971 return t;
1972 }
1974 @Override
1975 public Type visitClassType(ClassType t, Void ignored) {
1976 Type outer1 = classBound(t.getEnclosingType());
1977 if (outer1 != t.getEnclosingType())
1978 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
1979 else
1980 return t;
1981 }
1983 @Override
1984 public Type visitTypeVar(TypeVar t, Void ignored) {
1985 return classBound(supertype(t));
1986 }
1988 @Override
1989 public Type visitErrorType(ErrorType t, Void ignored) {
1990 return t;
1991 }
1992 };
1993 // </editor-fold>
1995 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
1996 /**
1997 * Returns true iff the first signature is a <em>sub
1998 * signature</em> of the other. This is <b>not</b> an equivalence
1999 * relation.
2000 *
2001 * @jls section 8.4.2.
2002 * @see #overrideEquivalent(Type t, Type s)
2003 * @param t first signature (possibly raw).
2004 * @param s second signature (could be subjected to erasure).
2005 * @return true if t is a sub signature of s.
2006 */
2007 public boolean isSubSignature(Type t, Type s) {
2008 return isSubSignature(t, s, true);
2009 }
2011 public boolean isSubSignature(Type t, Type s, boolean strict) {
2012 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2013 }
2015 /**
2016 * Returns true iff these signatures are related by <em>override
2017 * equivalence</em>. This is the natural extension of
2018 * isSubSignature to an equivalence relation.
2019 *
2020 * @jls section 8.4.2.
2021 * @see #isSubSignature(Type t, Type s)
2022 * @param t a signature (possible raw, could be subjected to
2023 * erasure).
2024 * @param s a signature (possible raw, could be subjected to
2025 * erasure).
2026 * @return true if either argument is a sub signature of the other.
2027 */
2028 public boolean overrideEquivalent(Type t, Type s) {
2029 return hasSameArgs(t, s) ||
2030 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2031 }
2033 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2034 class ImplementationCache {
2036 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
2037 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
2039 class Entry {
2040 final MethodSymbol cachedImpl;
2041 final Filter<Symbol> implFilter;
2042 final boolean checkResult;
2043 final int prevMark;
2045 public Entry(MethodSymbol cachedImpl,
2046 Filter<Symbol> scopeFilter,
2047 boolean checkResult,
2048 int prevMark) {
2049 this.cachedImpl = cachedImpl;
2050 this.implFilter = scopeFilter;
2051 this.checkResult = checkResult;
2052 this.prevMark = prevMark;
2053 }
2055 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
2056 return this.implFilter == scopeFilter &&
2057 this.checkResult == checkResult &&
2058 this.prevMark == mark;
2059 }
2060 }
2062 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2063 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2064 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2065 if (cache == null) {
2066 cache = new HashMap<TypeSymbol, Entry>();
2067 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2068 }
2069 Entry e = cache.get(origin);
2070 CompoundScope members = membersClosure(origin.type, true);
2071 if (e == null ||
2072 !e.matches(implFilter, checkResult, members.getMark())) {
2073 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2074 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2075 return impl;
2076 }
2077 else {
2078 return e.cachedImpl;
2079 }
2080 }
2082 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2083 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = supertype(t)) {
2084 while (t.tag == TYPEVAR)
2085 t = t.getUpperBound();
2086 TypeSymbol c = t.tsym;
2087 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2088 e.scope != null;
2089 e = e.next(implFilter)) {
2090 if (e.sym != null &&
2091 e.sym.overrides(ms, origin, Types.this, checkResult))
2092 return (MethodSymbol)e.sym;
2093 }
2094 }
2095 return null;
2096 }
2097 }
2099 private ImplementationCache implCache = new ImplementationCache();
2101 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2102 return implCache.get(ms, origin, checkResult, implFilter);
2103 }
2104 // </editor-fold>
2106 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2107 class MembersClosureCache extends SimpleVisitor<CompoundScope, Boolean> {
2109 private WeakHashMap<TypeSymbol, Entry> _map =
2110 new WeakHashMap<TypeSymbol, Entry>();
2112 class Entry {
2113 final boolean skipInterfaces;
2114 final CompoundScope compoundScope;
2116 public Entry(boolean skipInterfaces, CompoundScope compoundScope) {
2117 this.skipInterfaces = skipInterfaces;
2118 this.compoundScope = compoundScope;
2119 }
2121 boolean matches(boolean skipInterfaces) {
2122 return this.skipInterfaces == skipInterfaces;
2123 }
2124 }
2126 List<TypeSymbol> seenTypes = List.nil();
2128 /** members closure visitor methods **/
2130 public CompoundScope visitType(Type t, Boolean skipInterface) {
2131 return null;
2132 }
2134 @Override
2135 public CompoundScope visitClassType(ClassType t, Boolean skipInterface) {
2136 if (seenTypes.contains(t.tsym)) {
2137 //this is possible when an interface is implemented in multiple
2138 //superclasses, or when a classs hierarchy is circular - in such
2139 //cases we don't need to recurse (empty scope is returned)
2140 return new CompoundScope(t.tsym);
2141 }
2142 try {
2143 seenTypes = seenTypes.prepend(t.tsym);
2144 ClassSymbol csym = (ClassSymbol)t.tsym;
2145 Entry e = _map.get(csym);
2146 if (e == null || !e.matches(skipInterface)) {
2147 CompoundScope membersClosure = new CompoundScope(csym);
2148 if (!skipInterface) {
2149 for (Type i : interfaces(t)) {
2150 membersClosure.addSubScope(visit(i, skipInterface));
2151 }
2152 }
2153 membersClosure.addSubScope(visit(supertype(t), skipInterface));
2154 membersClosure.addSubScope(csym.members());
2155 e = new Entry(skipInterface, membersClosure);
2156 _map.put(csym, e);
2157 }
2158 return e.compoundScope;
2159 }
2160 finally {
2161 seenTypes = seenTypes.tail;
2162 }
2163 }
2165 @Override
2166 public CompoundScope visitTypeVar(TypeVar t, Boolean skipInterface) {
2167 return visit(t.getUpperBound(), skipInterface);
2168 }
2169 }
2171 private MembersClosureCache membersCache = new MembersClosureCache();
2173 public CompoundScope membersClosure(Type site, boolean skipInterface) {
2174 return membersCache.visit(site, skipInterface);
2175 }
2176 // </editor-fold>
2178 /**
2179 * Does t have the same arguments as s? It is assumed that both
2180 * types are (possibly polymorphic) method types. Monomorphic
2181 * method types "have the same arguments", if their argument lists
2182 * are equal. Polymorphic method types "have the same arguments",
2183 * if they have the same arguments after renaming all type
2184 * variables of one to corresponding type variables in the other,
2185 * where correspondence is by position in the type parameter list.
2186 */
2187 public boolean hasSameArgs(Type t, Type s) {
2188 return hasSameArgs(t, s, true);
2189 }
2191 public boolean hasSameArgs(Type t, Type s, boolean strict) {
2192 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
2193 }
2195 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
2196 return hasSameArgs.visit(t, s);
2197 }
2198 // where
2199 private class HasSameArgs extends TypeRelation {
2201 boolean strict;
2203 public HasSameArgs(boolean strict) {
2204 this.strict = strict;
2205 }
2207 public Boolean visitType(Type t, Type s) {
2208 throw new AssertionError();
2209 }
2211 @Override
2212 public Boolean visitMethodType(MethodType t, Type s) {
2213 return s.tag == METHOD
2214 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2215 }
2217 @Override
2218 public Boolean visitForAll(ForAll t, Type s) {
2219 if (s.tag != FORALL)
2220 return strict ? false : visitMethodType(t.asMethodType(), s);
2222 ForAll forAll = (ForAll)s;
2223 return hasSameBounds(t, forAll)
2224 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2225 }
2227 @Override
2228 public Boolean visitErrorType(ErrorType t, Type s) {
2229 return false;
2230 }
2231 };
2233 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
2234 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
2236 // </editor-fold>
2238 // <editor-fold defaultstate="collapsed" desc="subst">
2239 public List<Type> subst(List<Type> ts,
2240 List<Type> from,
2241 List<Type> to) {
2242 return new Subst(from, to).subst(ts);
2243 }
2245 /**
2246 * Substitute all occurrences of a type in `from' with the
2247 * corresponding type in `to' in 't'. Match lists `from' and `to'
2248 * from the right: If lists have different length, discard leading
2249 * elements of the longer list.
2250 */
2251 public Type subst(Type t, List<Type> from, List<Type> to) {
2252 return new Subst(from, to).subst(t);
2253 }
2255 private class Subst extends UnaryVisitor<Type> {
2256 List<Type> from;
2257 List<Type> to;
2259 public Subst(List<Type> from, List<Type> to) {
2260 int fromLength = from.length();
2261 int toLength = to.length();
2262 while (fromLength > toLength) {
2263 fromLength--;
2264 from = from.tail;
2265 }
2266 while (fromLength < toLength) {
2267 toLength--;
2268 to = to.tail;
2269 }
2270 this.from = from;
2271 this.to = to;
2272 }
2274 Type subst(Type t) {
2275 if (from.tail == null)
2276 return t;
2277 else
2278 return visit(t);
2279 }
2281 List<Type> subst(List<Type> ts) {
2282 if (from.tail == null)
2283 return ts;
2284 boolean wild = false;
2285 if (ts.nonEmpty() && from.nonEmpty()) {
2286 Type head1 = subst(ts.head);
2287 List<Type> tail1 = subst(ts.tail);
2288 if (head1 != ts.head || tail1 != ts.tail)
2289 return tail1.prepend(head1);
2290 }
2291 return ts;
2292 }
2294 public Type visitType(Type t, Void ignored) {
2295 return t;
2296 }
2298 @Override
2299 public Type visitMethodType(MethodType t, Void ignored) {
2300 List<Type> argtypes = subst(t.argtypes);
2301 Type restype = subst(t.restype);
2302 List<Type> thrown = subst(t.thrown);
2303 if (argtypes == t.argtypes &&
2304 restype == t.restype &&
2305 thrown == t.thrown)
2306 return t;
2307 else
2308 return new MethodType(argtypes, restype, thrown, t.tsym);
2309 }
2311 @Override
2312 public Type visitTypeVar(TypeVar t, Void ignored) {
2313 for (List<Type> from = this.from, to = this.to;
2314 from.nonEmpty();
2315 from = from.tail, to = to.tail) {
2316 if (t == from.head) {
2317 return to.head.withTypeVar(t);
2318 }
2319 }
2320 return t;
2321 }
2323 @Override
2324 public Type visitClassType(ClassType t, Void ignored) {
2325 if (!t.isCompound()) {
2326 List<Type> typarams = t.getTypeArguments();
2327 List<Type> typarams1 = subst(typarams);
2328 Type outer = t.getEnclosingType();
2329 Type outer1 = subst(outer);
2330 if (typarams1 == typarams && outer1 == outer)
2331 return t;
2332 else
2333 return new ClassType(outer1, typarams1, t.tsym);
2334 } else {
2335 Type st = subst(supertype(t));
2336 List<Type> is = upperBounds(subst(interfaces(t)));
2337 if (st == supertype(t) && is == interfaces(t))
2338 return t;
2339 else
2340 return makeCompoundType(is.prepend(st));
2341 }
2342 }
2344 @Override
2345 public Type visitWildcardType(WildcardType t, Void ignored) {
2346 Type bound = t.type;
2347 if (t.kind != BoundKind.UNBOUND)
2348 bound = subst(bound);
2349 if (bound == t.type) {
2350 return t;
2351 } else {
2352 if (t.isExtendsBound() && bound.isExtendsBound())
2353 bound = upperBound(bound);
2354 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2355 }
2356 }
2358 @Override
2359 public Type visitArrayType(ArrayType t, Void ignored) {
2360 Type elemtype = subst(t.elemtype);
2361 if (elemtype == t.elemtype)
2362 return t;
2363 else
2364 return new ArrayType(upperBound(elemtype), t.tsym);
2365 }
2367 @Override
2368 public Type visitForAll(ForAll t, Void ignored) {
2369 if (Type.containsAny(to, t.tvars)) {
2370 //perform alpha-renaming of free-variables in 't'
2371 //if 'to' types contain variables that are free in 't'
2372 List<Type> freevars = newInstances(t.tvars);
2373 t = new ForAll(freevars,
2374 Types.this.subst(t.qtype, t.tvars, freevars));
2375 }
2376 List<Type> tvars1 = substBounds(t.tvars, from, to);
2377 Type qtype1 = subst(t.qtype);
2378 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2379 return t;
2380 } else if (tvars1 == t.tvars) {
2381 return new ForAll(tvars1, qtype1);
2382 } else {
2383 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2384 }
2385 }
2387 @Override
2388 public Type visitErrorType(ErrorType t, Void ignored) {
2389 return t;
2390 }
2391 }
2393 public List<Type> substBounds(List<Type> tvars,
2394 List<Type> from,
2395 List<Type> to) {
2396 if (tvars.isEmpty())
2397 return tvars;
2398 ListBuffer<Type> newBoundsBuf = lb();
2399 boolean changed = false;
2400 // calculate new bounds
2401 for (Type t : tvars) {
2402 TypeVar tv = (TypeVar) t;
2403 Type bound = subst(tv.bound, from, to);
2404 if (bound != tv.bound)
2405 changed = true;
2406 newBoundsBuf.append(bound);
2407 }
2408 if (!changed)
2409 return tvars;
2410 ListBuffer<Type> newTvars = lb();
2411 // create new type variables without bounds
2412 for (Type t : tvars) {
2413 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2414 }
2415 // the new bounds should use the new type variables in place
2416 // of the old
2417 List<Type> newBounds = newBoundsBuf.toList();
2418 from = tvars;
2419 to = newTvars.toList();
2420 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2421 newBounds.head = subst(newBounds.head, from, to);
2422 }
2423 newBounds = newBoundsBuf.toList();
2424 // set the bounds of new type variables to the new bounds
2425 for (Type t : newTvars.toList()) {
2426 TypeVar tv = (TypeVar) t;
2427 tv.bound = newBounds.head;
2428 newBounds = newBounds.tail;
2429 }
2430 return newTvars.toList();
2431 }
2433 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2434 Type bound1 = subst(t.bound, from, to);
2435 if (bound1 == t.bound)
2436 return t;
2437 else {
2438 // create new type variable without bounds
2439 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2440 // the new bound should use the new type variable in place
2441 // of the old
2442 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2443 return tv;
2444 }
2445 }
2446 // </editor-fold>
2448 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2449 /**
2450 * Does t have the same bounds for quantified variables as s?
2451 */
2452 boolean hasSameBounds(ForAll t, ForAll s) {
2453 List<Type> l1 = t.tvars;
2454 List<Type> l2 = s.tvars;
2455 while (l1.nonEmpty() && l2.nonEmpty() &&
2456 isSameType(l1.head.getUpperBound(),
2457 subst(l2.head.getUpperBound(),
2458 s.tvars,
2459 t.tvars))) {
2460 l1 = l1.tail;
2461 l2 = l2.tail;
2462 }
2463 return l1.isEmpty() && l2.isEmpty();
2464 }
2465 // </editor-fold>
2467 // <editor-fold defaultstate="collapsed" desc="newInstances">
2468 /** Create new vector of type variables from list of variables
2469 * changing all recursive bounds from old to new list.
2470 */
2471 public List<Type> newInstances(List<Type> tvars) {
2472 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2473 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2474 TypeVar tv = (TypeVar) l.head;
2475 tv.bound = subst(tv.bound, tvars, tvars1);
2476 }
2477 return tvars1;
2478 }
2479 static private Mapping newInstanceFun = new Mapping("newInstanceFun") {
2480 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2481 };
2482 // </editor-fold>
2484 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
2485 return original.accept(methodWithParameters, newParams);
2486 }
2487 // where
2488 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
2489 public Type visitType(Type t, List<Type> newParams) {
2490 throw new IllegalArgumentException("Not a method type: " + t);
2491 }
2492 public Type visitMethodType(MethodType t, List<Type> newParams) {
2493 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
2494 }
2495 public Type visitForAll(ForAll t, List<Type> newParams) {
2496 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
2497 }
2498 };
2500 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
2501 return original.accept(methodWithThrown, newThrown);
2502 }
2503 // where
2504 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
2505 public Type visitType(Type t, List<Type> newThrown) {
2506 throw new IllegalArgumentException("Not a method type: " + t);
2507 }
2508 public Type visitMethodType(MethodType t, List<Type> newThrown) {
2509 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
2510 }
2511 public Type visitForAll(ForAll t, List<Type> newThrown) {
2512 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
2513 }
2514 };
2516 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
2517 return original.accept(methodWithReturn, newReturn);
2518 }
2519 // where
2520 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
2521 public Type visitType(Type t, Type newReturn) {
2522 throw new IllegalArgumentException("Not a method type: " + t);
2523 }
2524 public Type visitMethodType(MethodType t, Type newReturn) {
2525 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym);
2526 }
2527 public Type visitForAll(ForAll t, Type newReturn) {
2528 return new ForAll(t.tvars, t.qtype.accept(this, newReturn));
2529 }
2530 };
2532 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2533 public Type createErrorType(Type originalType) {
2534 return new ErrorType(originalType, syms.errSymbol);
2535 }
2537 public Type createErrorType(ClassSymbol c, Type originalType) {
2538 return new ErrorType(c, originalType);
2539 }
2541 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
2542 return new ErrorType(name, container, originalType);
2543 }
2544 // </editor-fold>
2546 // <editor-fold defaultstate="collapsed" desc="rank">
2547 /**
2548 * The rank of a class is the length of the longest path between
2549 * the class and java.lang.Object in the class inheritance
2550 * graph. Undefined for all but reference types.
2551 */
2552 public int rank(Type t) {
2553 switch(t.tag) {
2554 case CLASS: {
2555 ClassType cls = (ClassType)t;
2556 if (cls.rank_field < 0) {
2557 Name fullname = cls.tsym.getQualifiedName();
2558 if (fullname == names.java_lang_Object)
2559 cls.rank_field = 0;
2560 else {
2561 int r = rank(supertype(cls));
2562 for (List<Type> l = interfaces(cls);
2563 l.nonEmpty();
2564 l = l.tail) {
2565 if (rank(l.head) > r)
2566 r = rank(l.head);
2567 }
2568 cls.rank_field = r + 1;
2569 }
2570 }
2571 return cls.rank_field;
2572 }
2573 case TYPEVAR: {
2574 TypeVar tvar = (TypeVar)t;
2575 if (tvar.rank_field < 0) {
2576 int r = rank(supertype(tvar));
2577 for (List<Type> l = interfaces(tvar);
2578 l.nonEmpty();
2579 l = l.tail) {
2580 if (rank(l.head) > r) r = rank(l.head);
2581 }
2582 tvar.rank_field = r + 1;
2583 }
2584 return tvar.rank_field;
2585 }
2586 case ERROR:
2587 return 0;
2588 default:
2589 throw new AssertionError();
2590 }
2591 }
2592 // </editor-fold>
2594 /**
2595 * Helper method for generating a string representation of a given type
2596 * accordingly to a given locale
2597 */
2598 public String toString(Type t, Locale locale) {
2599 return Printer.createStandardPrinter(messages).visit(t, locale);
2600 }
2602 /**
2603 * Helper method for generating a string representation of a given type
2604 * accordingly to a given locale
2605 */
2606 public String toString(Symbol t, Locale locale) {
2607 return Printer.createStandardPrinter(messages).visit(t, locale);
2608 }
2610 // <editor-fold defaultstate="collapsed" desc="toString">
2611 /**
2612 * This toString is slightly more descriptive than the one on Type.
2613 *
2614 * @deprecated Types.toString(Type t, Locale l) provides better support
2615 * for localization
2616 */
2617 @Deprecated
2618 public String toString(Type t) {
2619 if (t.tag == FORALL) {
2620 ForAll forAll = (ForAll)t;
2621 return typaramsString(forAll.tvars) + forAll.qtype;
2622 }
2623 return "" + t;
2624 }
2625 // where
2626 private String typaramsString(List<Type> tvars) {
2627 StringBuilder s = new StringBuilder();
2628 s.append('<');
2629 boolean first = true;
2630 for (Type t : tvars) {
2631 if (!first) s.append(", ");
2632 first = false;
2633 appendTyparamString(((TypeVar)t), s);
2634 }
2635 s.append('>');
2636 return s.toString();
2637 }
2638 private void appendTyparamString(TypeVar t, StringBuilder buf) {
2639 buf.append(t);
2640 if (t.bound == null ||
2641 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
2642 return;
2643 buf.append(" extends "); // Java syntax; no need for i18n
2644 Type bound = t.bound;
2645 if (!bound.isCompound()) {
2646 buf.append(bound);
2647 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
2648 buf.append(supertype(t));
2649 for (Type intf : interfaces(t)) {
2650 buf.append('&');
2651 buf.append(intf);
2652 }
2653 } else {
2654 // No superclass was given in bounds.
2655 // In this case, supertype is Object, erasure is first interface.
2656 boolean first = true;
2657 for (Type intf : interfaces(t)) {
2658 if (!first) buf.append('&');
2659 first = false;
2660 buf.append(intf);
2661 }
2662 }
2663 }
2664 // </editor-fold>
2666 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
2667 /**
2668 * A cache for closures.
2669 *
2670 * <p>A closure is a list of all the supertypes and interfaces of
2671 * a class or interface type, ordered by ClassSymbol.precedes
2672 * (that is, subclasses come first, arbitrary but fixed
2673 * otherwise).
2674 */
2675 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
2677 /**
2678 * Returns the closure of a class or interface type.
2679 */
2680 public List<Type> closure(Type t) {
2681 List<Type> cl = closureCache.get(t);
2682 if (cl == null) {
2683 Type st = supertype(t);
2684 if (!t.isCompound()) {
2685 if (st.tag == CLASS) {
2686 cl = insert(closure(st), t);
2687 } else if (st.tag == TYPEVAR) {
2688 cl = closure(st).prepend(t);
2689 } else {
2690 cl = List.of(t);
2691 }
2692 } else {
2693 cl = closure(supertype(t));
2694 }
2695 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
2696 cl = union(cl, closure(l.head));
2697 closureCache.put(t, cl);
2698 }
2699 return cl;
2700 }
2702 /**
2703 * Insert a type in a closure
2704 */
2705 public List<Type> insert(List<Type> cl, Type t) {
2706 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
2707 return cl.prepend(t);
2708 } else if (cl.head.tsym.precedes(t.tsym, this)) {
2709 return insert(cl.tail, t).prepend(cl.head);
2710 } else {
2711 return cl;
2712 }
2713 }
2715 /**
2716 * Form the union of two closures
2717 */
2718 public List<Type> union(List<Type> cl1, List<Type> cl2) {
2719 if (cl1.isEmpty()) {
2720 return cl2;
2721 } else if (cl2.isEmpty()) {
2722 return cl1;
2723 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
2724 return union(cl1.tail, cl2).prepend(cl1.head);
2725 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
2726 return union(cl1, cl2.tail).prepend(cl2.head);
2727 } else {
2728 return union(cl1.tail, cl2.tail).prepend(cl1.head);
2729 }
2730 }
2732 /**
2733 * Intersect two closures
2734 */
2735 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
2736 if (cl1 == cl2)
2737 return cl1;
2738 if (cl1.isEmpty() || cl2.isEmpty())
2739 return List.nil();
2740 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
2741 return intersect(cl1.tail, cl2);
2742 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
2743 return intersect(cl1, cl2.tail);
2744 if (isSameType(cl1.head, cl2.head))
2745 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
2746 if (cl1.head.tsym == cl2.head.tsym &&
2747 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
2748 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
2749 Type merge = merge(cl1.head,cl2.head);
2750 return intersect(cl1.tail, cl2.tail).prepend(merge);
2751 }
2752 if (cl1.head.isRaw() || cl2.head.isRaw())
2753 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
2754 }
2755 return intersect(cl1.tail, cl2.tail);
2756 }
2757 // where
2758 class TypePair {
2759 final Type t1;
2760 final Type t2;
2761 TypePair(Type t1, Type t2) {
2762 this.t1 = t1;
2763 this.t2 = t2;
2764 }
2765 @Override
2766 public int hashCode() {
2767 return 127 * Types.hashCode(t1) + Types.hashCode(t2);
2768 }
2769 @Override
2770 public boolean equals(Object obj) {
2771 if (!(obj instanceof TypePair))
2772 return false;
2773 TypePair typePair = (TypePair)obj;
2774 return isSameType(t1, typePair.t1)
2775 && isSameType(t2, typePair.t2);
2776 }
2777 }
2778 Set<TypePair> mergeCache = new HashSet<TypePair>();
2779 private Type merge(Type c1, Type c2) {
2780 ClassType class1 = (ClassType) c1;
2781 List<Type> act1 = class1.getTypeArguments();
2782 ClassType class2 = (ClassType) c2;
2783 List<Type> act2 = class2.getTypeArguments();
2784 ListBuffer<Type> merged = new ListBuffer<Type>();
2785 List<Type> typarams = class1.tsym.type.getTypeArguments();
2787 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
2788 if (containsType(act1.head, act2.head)) {
2789 merged.append(act1.head);
2790 } else if (containsType(act2.head, act1.head)) {
2791 merged.append(act2.head);
2792 } else {
2793 TypePair pair = new TypePair(c1, c2);
2794 Type m;
2795 if (mergeCache.add(pair)) {
2796 m = new WildcardType(lub(upperBound(act1.head),
2797 upperBound(act2.head)),
2798 BoundKind.EXTENDS,
2799 syms.boundClass);
2800 mergeCache.remove(pair);
2801 } else {
2802 m = new WildcardType(syms.objectType,
2803 BoundKind.UNBOUND,
2804 syms.boundClass);
2805 }
2806 merged.append(m.withTypeVar(typarams.head));
2807 }
2808 act1 = act1.tail;
2809 act2 = act2.tail;
2810 typarams = typarams.tail;
2811 }
2812 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
2813 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
2814 }
2816 /**
2817 * Return the minimum type of a closure, a compound type if no
2818 * unique minimum exists.
2819 */
2820 private Type compoundMin(List<Type> cl) {
2821 if (cl.isEmpty()) return syms.objectType;
2822 List<Type> compound = closureMin(cl);
2823 if (compound.isEmpty())
2824 return null;
2825 else if (compound.tail.isEmpty())
2826 return compound.head;
2827 else
2828 return makeCompoundType(compound);
2829 }
2831 /**
2832 * Return the minimum types of a closure, suitable for computing
2833 * compoundMin or glb.
2834 */
2835 private List<Type> closureMin(List<Type> cl) {
2836 ListBuffer<Type> classes = lb();
2837 ListBuffer<Type> interfaces = lb();
2838 while (!cl.isEmpty()) {
2839 Type current = cl.head;
2840 if (current.isInterface())
2841 interfaces.append(current);
2842 else
2843 classes.append(current);
2844 ListBuffer<Type> candidates = lb();
2845 for (Type t : cl.tail) {
2846 if (!isSubtypeNoCapture(current, t))
2847 candidates.append(t);
2848 }
2849 cl = candidates.toList();
2850 }
2851 return classes.appendList(interfaces).toList();
2852 }
2854 /**
2855 * Return the least upper bound of pair of types. if the lub does
2856 * not exist return null.
2857 */
2858 public Type lub(Type t1, Type t2) {
2859 return lub(List.of(t1, t2));
2860 }
2862 /**
2863 * Return the least upper bound (lub) of set of types. If the lub
2864 * does not exist return the type of null (bottom).
2865 */
2866 public Type lub(List<Type> ts) {
2867 final int ARRAY_BOUND = 1;
2868 final int CLASS_BOUND = 2;
2869 int boundkind = 0;
2870 for (Type t : ts) {
2871 switch (t.tag) {
2872 case CLASS:
2873 boundkind |= CLASS_BOUND;
2874 break;
2875 case ARRAY:
2876 boundkind |= ARRAY_BOUND;
2877 break;
2878 case TYPEVAR:
2879 do {
2880 t = t.getUpperBound();
2881 } while (t.tag == TYPEVAR);
2882 if (t.tag == ARRAY) {
2883 boundkind |= ARRAY_BOUND;
2884 } else {
2885 boundkind |= CLASS_BOUND;
2886 }
2887 break;
2888 default:
2889 if (t.isPrimitive())
2890 return syms.errType;
2891 }
2892 }
2893 switch (boundkind) {
2894 case 0:
2895 return syms.botType;
2897 case ARRAY_BOUND:
2898 // calculate lub(A[], B[])
2899 List<Type> elements = Type.map(ts, elemTypeFun);
2900 for (Type t : elements) {
2901 if (t.isPrimitive()) {
2902 // if a primitive type is found, then return
2903 // arraySuperType unless all the types are the
2904 // same
2905 Type first = ts.head;
2906 for (Type s : ts.tail) {
2907 if (!isSameType(first, s)) {
2908 // lub(int[], B[]) is Cloneable & Serializable
2909 return arraySuperType();
2910 }
2911 }
2912 // all the array types are the same, return one
2913 // lub(int[], int[]) is int[]
2914 return first;
2915 }
2916 }
2917 // lub(A[], B[]) is lub(A, B)[]
2918 return new ArrayType(lub(elements), syms.arrayClass);
2920 case CLASS_BOUND:
2921 // calculate lub(A, B)
2922 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
2923 ts = ts.tail;
2924 Assert.check(!ts.isEmpty());
2925 //step 1 - compute erased candidate set (EC)
2926 List<Type> cl = erasedSupertypes(ts.head);
2927 for (Type t : ts.tail) {
2928 if (t.tag == CLASS || t.tag == TYPEVAR)
2929 cl = intersect(cl, erasedSupertypes(t));
2930 }
2931 //step 2 - compute minimal erased candidate set (MEC)
2932 List<Type> mec = closureMin(cl);
2933 //step 3 - for each element G in MEC, compute lci(Inv(G))
2934 List<Type> candidates = List.nil();
2935 for (Type erasedSupertype : mec) {
2936 List<Type> lci = List.of(asSuper(ts.head, erasedSupertype.tsym));
2937 for (Type t : ts) {
2938 lci = intersect(lci, List.of(asSuper(t, erasedSupertype.tsym)));
2939 }
2940 candidates = candidates.appendList(lci);
2941 }
2942 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
2943 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
2944 return compoundMin(candidates);
2946 default:
2947 // calculate lub(A, B[])
2948 List<Type> classes = List.of(arraySuperType());
2949 for (Type t : ts) {
2950 if (t.tag != ARRAY) // Filter out any arrays
2951 classes = classes.prepend(t);
2952 }
2953 // lub(A, B[]) is lub(A, arraySuperType)
2954 return lub(classes);
2955 }
2956 }
2957 // where
2958 List<Type> erasedSupertypes(Type t) {
2959 ListBuffer<Type> buf = lb();
2960 for (Type sup : closure(t)) {
2961 if (sup.tag == TYPEVAR) {
2962 buf.append(sup);
2963 } else {
2964 buf.append(erasure(sup));
2965 }
2966 }
2967 return buf.toList();
2968 }
2970 private Type arraySuperType = null;
2971 private Type arraySuperType() {
2972 // initialized lazily to avoid problems during compiler startup
2973 if (arraySuperType == null) {
2974 synchronized (this) {
2975 if (arraySuperType == null) {
2976 // JLS 10.8: all arrays implement Cloneable and Serializable.
2977 arraySuperType = makeCompoundType(List.of(syms.serializableType,
2978 syms.cloneableType),
2979 syms.objectType);
2980 }
2981 }
2982 }
2983 return arraySuperType;
2984 }
2985 // </editor-fold>
2987 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
2988 public Type glb(List<Type> ts) {
2989 Type t1 = ts.head;
2990 for (Type t2 : ts.tail) {
2991 if (t1.isErroneous())
2992 return t1;
2993 t1 = glb(t1, t2);
2994 }
2995 return t1;
2996 }
2997 //where
2998 public Type glb(Type t, Type s) {
2999 if (s == null)
3000 return t;
3001 else if (t.isPrimitive() || s.isPrimitive())
3002 return syms.errType;
3003 else if (isSubtypeNoCapture(t, s))
3004 return t;
3005 else if (isSubtypeNoCapture(s, t))
3006 return s;
3008 List<Type> closure = union(closure(t), closure(s));
3009 List<Type> bounds = closureMin(closure);
3011 if (bounds.isEmpty()) { // length == 0
3012 return syms.objectType;
3013 } else if (bounds.tail.isEmpty()) { // length == 1
3014 return bounds.head;
3015 } else { // length > 1
3016 int classCount = 0;
3017 for (Type bound : bounds)
3018 if (!bound.isInterface())
3019 classCount++;
3020 if (classCount > 1)
3021 return createErrorType(t);
3022 }
3023 return makeCompoundType(bounds);
3024 }
3025 // </editor-fold>
3027 // <editor-fold defaultstate="collapsed" desc="hashCode">
3028 /**
3029 * Compute a hash code on a type.
3030 */
3031 public static int hashCode(Type t) {
3032 return hashCode.visit(t);
3033 }
3034 // where
3035 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
3037 public Integer visitType(Type t, Void ignored) {
3038 return t.tag;
3039 }
3041 @Override
3042 public Integer visitClassType(ClassType t, Void ignored) {
3043 int result = visit(t.getEnclosingType());
3044 result *= 127;
3045 result += t.tsym.flatName().hashCode();
3046 for (Type s : t.getTypeArguments()) {
3047 result *= 127;
3048 result += visit(s);
3049 }
3050 return result;
3051 }
3053 @Override
3054 public Integer visitWildcardType(WildcardType t, Void ignored) {
3055 int result = t.kind.hashCode();
3056 if (t.type != null) {
3057 result *= 127;
3058 result += visit(t.type);
3059 }
3060 return result;
3061 }
3063 @Override
3064 public Integer visitArrayType(ArrayType t, Void ignored) {
3065 return visit(t.elemtype) + 12;
3066 }
3068 @Override
3069 public Integer visitTypeVar(TypeVar t, Void ignored) {
3070 return System.identityHashCode(t.tsym);
3071 }
3073 @Override
3074 public Integer visitUndetVar(UndetVar t, Void ignored) {
3075 return System.identityHashCode(t);
3076 }
3078 @Override
3079 public Integer visitErrorType(ErrorType t, Void ignored) {
3080 return 0;
3081 }
3082 };
3083 // </editor-fold>
3085 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
3086 /**
3087 * Does t have a result that is a subtype of the result type of s,
3088 * suitable for covariant returns? It is assumed that both types
3089 * are (possibly polymorphic) method types. Monomorphic method
3090 * types are handled in the obvious way. Polymorphic method types
3091 * require renaming all type variables of one to corresponding
3092 * type variables in the other, where correspondence is by
3093 * position in the type parameter list. */
3094 public boolean resultSubtype(Type t, Type s, Warner warner) {
3095 List<Type> tvars = t.getTypeArguments();
3096 List<Type> svars = s.getTypeArguments();
3097 Type tres = t.getReturnType();
3098 Type sres = subst(s.getReturnType(), svars, tvars);
3099 return covariantReturnType(tres, sres, warner);
3100 }
3102 /**
3103 * Return-Type-Substitutable.
3104 * @jls section 8.4.5
3105 */
3106 public boolean returnTypeSubstitutable(Type r1, Type r2) {
3107 if (hasSameArgs(r1, r2))
3108 return resultSubtype(r1, r2, Warner.noWarnings);
3109 else
3110 return covariantReturnType(r1.getReturnType(),
3111 erasure(r2.getReturnType()),
3112 Warner.noWarnings);
3113 }
3115 public boolean returnTypeSubstitutable(Type r1,
3116 Type r2, Type r2res,
3117 Warner warner) {
3118 if (isSameType(r1.getReturnType(), r2res))
3119 return true;
3120 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
3121 return false;
3123 if (hasSameArgs(r1, r2))
3124 return covariantReturnType(r1.getReturnType(), r2res, warner);
3125 if (!allowCovariantReturns)
3126 return false;
3127 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
3128 return true;
3129 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
3130 return false;
3131 warner.warn(LintCategory.UNCHECKED);
3132 return true;
3133 }
3135 /**
3136 * Is t an appropriate return type in an overrider for a
3137 * method that returns s?
3138 */
3139 public boolean covariantReturnType(Type t, Type s, Warner warner) {
3140 return
3141 isSameType(t, s) ||
3142 allowCovariantReturns &&
3143 !t.isPrimitive() &&
3144 !s.isPrimitive() &&
3145 isAssignable(t, s, warner);
3146 }
3147 // </editor-fold>
3149 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
3150 /**
3151 * Return the class that boxes the given primitive.
3152 */
3153 public ClassSymbol boxedClass(Type t) {
3154 return reader.enterClass(syms.boxedName[t.tag]);
3155 }
3157 /**
3158 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
3159 */
3160 public Type boxedTypeOrType(Type t) {
3161 return t.isPrimitive() ?
3162 boxedClass(t).type :
3163 t;
3164 }
3166 /**
3167 * Return the primitive type corresponding to a boxed type.
3168 */
3169 public Type unboxedType(Type t) {
3170 if (allowBoxing) {
3171 for (int i=0; i<syms.boxedName.length; i++) {
3172 Name box = syms.boxedName[i];
3173 if (box != null &&
3174 asSuper(t, reader.enterClass(box)) != null)
3175 return syms.typeOfTag[i];
3176 }
3177 }
3178 return Type.noType;
3179 }
3180 // </editor-fold>
3182 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3183 /*
3184 * JLS 5.1.10 Capture Conversion:
3185 *
3186 * Let G name a generic type declaration with n formal type
3187 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3188 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3189 * where, for 1 <= i <= n:
3190 *
3191 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3192 * Si is a fresh type variable whose upper bound is
3193 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3194 * type.
3195 *
3196 * + If Ti is a wildcard type argument of the form ? extends Bi,
3197 * then Si is a fresh type variable whose upper bound is
3198 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3199 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3200 * a compile-time error if for any two classes (not interfaces)
3201 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3202 *
3203 * + If Ti is a wildcard type argument of the form ? super Bi,
3204 * then Si is a fresh type variable whose upper bound is
3205 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3206 *
3207 * + Otherwise, Si = Ti.
3208 *
3209 * Capture conversion on any type other than a parameterized type
3210 * (4.5) acts as an identity conversion (5.1.1). Capture
3211 * conversions never require a special action at run time and
3212 * therefore never throw an exception at run time.
3213 *
3214 * Capture conversion is not applied recursively.
3215 */
3216 /**
3217 * Capture conversion as specified by the JLS.
3218 */
3220 public List<Type> capture(List<Type> ts) {
3221 List<Type> buf = List.nil();
3222 for (Type t : ts) {
3223 buf = buf.prepend(capture(t));
3224 }
3225 return buf.reverse();
3226 }
3227 public Type capture(Type t) {
3228 if (t.tag != CLASS)
3229 return t;
3230 if (t.getEnclosingType() != Type.noType) {
3231 Type capturedEncl = capture(t.getEnclosingType());
3232 if (capturedEncl != t.getEnclosingType()) {
3233 Type type1 = memberType(capturedEncl, t.tsym);
3234 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3235 }
3236 }
3237 ClassType cls = (ClassType)t;
3238 if (cls.isRaw() || !cls.isParameterized())
3239 return cls;
3241 ClassType G = (ClassType)cls.asElement().asType();
3242 List<Type> A = G.getTypeArguments();
3243 List<Type> T = cls.getTypeArguments();
3244 List<Type> S = freshTypeVariables(T);
3246 List<Type> currentA = A;
3247 List<Type> currentT = T;
3248 List<Type> currentS = S;
3249 boolean captured = false;
3250 while (!currentA.isEmpty() &&
3251 !currentT.isEmpty() &&
3252 !currentS.isEmpty()) {
3253 if (currentS.head != currentT.head) {
3254 captured = true;
3255 WildcardType Ti = (WildcardType)currentT.head;
3256 Type Ui = currentA.head.getUpperBound();
3257 CapturedType Si = (CapturedType)currentS.head;
3258 if (Ui == null)
3259 Ui = syms.objectType;
3260 switch (Ti.kind) {
3261 case UNBOUND:
3262 Si.bound = subst(Ui, A, S);
3263 Si.lower = syms.botType;
3264 break;
3265 case EXTENDS:
3266 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3267 Si.lower = syms.botType;
3268 break;
3269 case SUPER:
3270 Si.bound = subst(Ui, A, S);
3271 Si.lower = Ti.getSuperBound();
3272 break;
3273 }
3274 if (Si.bound == Si.lower)
3275 currentS.head = Si.bound;
3276 }
3277 currentA = currentA.tail;
3278 currentT = currentT.tail;
3279 currentS = currentS.tail;
3280 }
3281 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3282 return erasure(t); // some "rare" type involved
3284 if (captured)
3285 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3286 else
3287 return t;
3288 }
3289 // where
3290 public List<Type> freshTypeVariables(List<Type> types) {
3291 ListBuffer<Type> result = lb();
3292 for (Type t : types) {
3293 if (t.tag == WILDCARD) {
3294 Type bound = ((WildcardType)t).getExtendsBound();
3295 if (bound == null)
3296 bound = syms.objectType;
3297 result.append(new CapturedType(capturedName,
3298 syms.noSymbol,
3299 bound,
3300 syms.botType,
3301 (WildcardType)t));
3302 } else {
3303 result.append(t);
3304 }
3305 }
3306 return result.toList();
3307 }
3308 // </editor-fold>
3310 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3311 private List<Type> upperBounds(List<Type> ss) {
3312 if (ss.isEmpty()) return ss;
3313 Type head = upperBound(ss.head);
3314 List<Type> tail = upperBounds(ss.tail);
3315 if (head != ss.head || tail != ss.tail)
3316 return tail.prepend(head);
3317 else
3318 return ss;
3319 }
3321 private boolean sideCast(Type from, Type to, Warner warn) {
3322 // We are casting from type $from$ to type $to$, which are
3323 // non-final unrelated types. This method
3324 // tries to reject a cast by transferring type parameters
3325 // from $to$ to $from$ by common superinterfaces.
3326 boolean reverse = false;
3327 Type target = to;
3328 if ((to.tsym.flags() & INTERFACE) == 0) {
3329 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3330 reverse = true;
3331 to = from;
3332 from = target;
3333 }
3334 List<Type> commonSupers = superClosure(to, erasure(from));
3335 boolean giveWarning = commonSupers.isEmpty();
3336 // The arguments to the supers could be unified here to
3337 // get a more accurate analysis
3338 while (commonSupers.nonEmpty()) {
3339 Type t1 = asSuper(from, commonSupers.head.tsym);
3340 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3341 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3342 return false;
3343 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3344 commonSupers = commonSupers.tail;
3345 }
3346 if (giveWarning && !isReifiable(reverse ? from : to))
3347 warn.warn(LintCategory.UNCHECKED);
3348 if (!allowCovariantReturns)
3349 // reject if there is a common method signature with
3350 // incompatible return types.
3351 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3352 return true;
3353 }
3355 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3356 // We are casting from type $from$ to type $to$, which are
3357 // unrelated types one of which is final and the other of
3358 // which is an interface. This method
3359 // tries to reject a cast by transferring type parameters
3360 // from the final class to the interface.
3361 boolean reverse = false;
3362 Type target = to;
3363 if ((to.tsym.flags() & INTERFACE) == 0) {
3364 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3365 reverse = true;
3366 to = from;
3367 from = target;
3368 }
3369 Assert.check((from.tsym.flags() & FINAL) != 0);
3370 Type t1 = asSuper(from, to.tsym);
3371 if (t1 == null) return false;
3372 Type t2 = to;
3373 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3374 return false;
3375 if (!allowCovariantReturns)
3376 // reject if there is a common method signature with
3377 // incompatible return types.
3378 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3379 if (!isReifiable(target) &&
3380 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3381 warn.warn(LintCategory.UNCHECKED);
3382 return true;
3383 }
3385 private boolean giveWarning(Type from, Type to) {
3386 Type subFrom = asSub(from, to.tsym);
3387 return to.isParameterized() &&
3388 (!(isUnbounded(to) ||
3389 isSubtype(from, to) ||
3390 ((subFrom != null) && containsType(to.allparams(), subFrom.allparams()))));
3391 }
3393 private List<Type> superClosure(Type t, Type s) {
3394 List<Type> cl = List.nil();
3395 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3396 if (isSubtype(s, erasure(l.head))) {
3397 cl = insert(cl, l.head);
3398 } else {
3399 cl = union(cl, superClosure(l.head, s));
3400 }
3401 }
3402 return cl;
3403 }
3405 private boolean containsTypeEquivalent(Type t, Type s) {
3406 return
3407 isSameType(t, s) || // shortcut
3408 containsType(t, s) && containsType(s, t);
3409 }
3411 // <editor-fold defaultstate="collapsed" desc="adapt">
3412 /**
3413 * Adapt a type by computing a substitution which maps a source
3414 * type to a target type.
3415 *
3416 * @param source the source type
3417 * @param target the target type
3418 * @param from the type variables of the computed substitution
3419 * @param to the types of the computed substitution.
3420 */
3421 public void adapt(Type source,
3422 Type target,
3423 ListBuffer<Type> from,
3424 ListBuffer<Type> to) throws AdaptFailure {
3425 new Adapter(from, to).adapt(source, target);
3426 }
3428 class Adapter extends SimpleVisitor<Void, Type> {
3430 ListBuffer<Type> from;
3431 ListBuffer<Type> to;
3432 Map<Symbol,Type> mapping;
3434 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3435 this.from = from;
3436 this.to = to;
3437 mapping = new HashMap<Symbol,Type>();
3438 }
3440 public void adapt(Type source, Type target) throws AdaptFailure {
3441 visit(source, target);
3442 List<Type> fromList = from.toList();
3443 List<Type> toList = to.toList();
3444 while (!fromList.isEmpty()) {
3445 Type val = mapping.get(fromList.head.tsym);
3446 if (toList.head != val)
3447 toList.head = val;
3448 fromList = fromList.tail;
3449 toList = toList.tail;
3450 }
3451 }
3453 @Override
3454 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3455 if (target.tag == CLASS)
3456 adaptRecursive(source.allparams(), target.allparams());
3457 return null;
3458 }
3460 @Override
3461 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3462 if (target.tag == ARRAY)
3463 adaptRecursive(elemtype(source), elemtype(target));
3464 return null;
3465 }
3467 @Override
3468 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3469 if (source.isExtendsBound())
3470 adaptRecursive(upperBound(source), upperBound(target));
3471 else if (source.isSuperBound())
3472 adaptRecursive(lowerBound(source), lowerBound(target));
3473 return null;
3474 }
3476 @Override
3477 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3478 // Check to see if there is
3479 // already a mapping for $source$, in which case
3480 // the old mapping will be merged with the new
3481 Type val = mapping.get(source.tsym);
3482 if (val != null) {
3483 if (val.isSuperBound() && target.isSuperBound()) {
3484 val = isSubtype(lowerBound(val), lowerBound(target))
3485 ? target : val;
3486 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3487 val = isSubtype(upperBound(val), upperBound(target))
3488 ? val : target;
3489 } else if (!isSameType(val, target)) {
3490 throw new AdaptFailure();
3491 }
3492 } else {
3493 val = target;
3494 from.append(source);
3495 to.append(target);
3496 }
3497 mapping.put(source.tsym, val);
3498 return null;
3499 }
3501 @Override
3502 public Void visitType(Type source, Type target) {
3503 return null;
3504 }
3506 private Set<TypePair> cache = new HashSet<TypePair>();
3508 private void adaptRecursive(Type source, Type target) {
3509 TypePair pair = new TypePair(source, target);
3510 if (cache.add(pair)) {
3511 try {
3512 visit(source, target);
3513 } finally {
3514 cache.remove(pair);
3515 }
3516 }
3517 }
3519 private void adaptRecursive(List<Type> source, List<Type> target) {
3520 if (source.length() == target.length()) {
3521 while (source.nonEmpty()) {
3522 adaptRecursive(source.head, target.head);
3523 source = source.tail;
3524 target = target.tail;
3525 }
3526 }
3527 }
3528 }
3530 public static class AdaptFailure extends RuntimeException {
3531 static final long serialVersionUID = -7490231548272701566L;
3532 }
3534 private void adaptSelf(Type t,
3535 ListBuffer<Type> from,
3536 ListBuffer<Type> to) {
3537 try {
3538 //if (t.tsym.type != t)
3539 adapt(t.tsym.type, t, from, to);
3540 } catch (AdaptFailure ex) {
3541 // Adapt should never fail calculating a mapping from
3542 // t.tsym.type to t as there can be no merge problem.
3543 throw new AssertionError(ex);
3544 }
3545 }
3546 // </editor-fold>
3548 /**
3549 * Rewrite all type variables (universal quantifiers) in the given
3550 * type to wildcards (existential quantifiers). This is used to
3551 * determine if a cast is allowed. For example, if high is true
3552 * and {@code T <: Number}, then {@code List<T>} is rewritten to
3553 * {@code List<? extends Number>}. Since {@code List<Integer> <:
3554 * List<? extends Number>} a {@code List<T>} can be cast to {@code
3555 * List<Integer>} with a warning.
3556 * @param t a type
3557 * @param high if true return an upper bound; otherwise a lower
3558 * bound
3559 * @param rewriteTypeVars only rewrite captured wildcards if false;
3560 * otherwise rewrite all type variables
3561 * @return the type rewritten with wildcards (existential
3562 * quantifiers) only
3563 */
3564 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
3565 return new Rewriter(high, rewriteTypeVars).visit(t);
3566 }
3568 class Rewriter extends UnaryVisitor<Type> {
3570 boolean high;
3571 boolean rewriteTypeVars;
3573 Rewriter(boolean high, boolean rewriteTypeVars) {
3574 this.high = high;
3575 this.rewriteTypeVars = rewriteTypeVars;
3576 }
3578 @Override
3579 public Type visitClassType(ClassType t, Void s) {
3580 ListBuffer<Type> rewritten = new ListBuffer<Type>();
3581 boolean changed = false;
3582 for (Type arg : t.allparams()) {
3583 Type bound = visit(arg);
3584 if (arg != bound) {
3585 changed = true;
3586 }
3587 rewritten.append(bound);
3588 }
3589 if (changed)
3590 return subst(t.tsym.type,
3591 t.tsym.type.allparams(),
3592 rewritten.toList());
3593 else
3594 return t;
3595 }
3597 public Type visitType(Type t, Void s) {
3598 return high ? upperBound(t) : lowerBound(t);
3599 }
3601 @Override
3602 public Type visitCapturedType(CapturedType t, Void s) {
3603 Type bound = visitWildcardType(t.wildcard, null);
3604 return (bound.contains(t)) ?
3605 erasure(bound) :
3606 bound;
3607 }
3609 @Override
3610 public Type visitTypeVar(TypeVar t, Void s) {
3611 if (rewriteTypeVars) {
3612 Type bound = high ?
3613 (t.bound.contains(t) ?
3614 erasure(t.bound) :
3615 visit(t.bound)) :
3616 syms.botType;
3617 return rewriteAsWildcardType(bound, t);
3618 }
3619 else
3620 return t;
3621 }
3623 @Override
3624 public Type visitWildcardType(WildcardType t, Void s) {
3625 Type bound = high ? t.getExtendsBound() :
3626 t.getSuperBound();
3627 if (bound == null)
3628 bound = high ? syms.objectType : syms.botType;
3629 return rewriteAsWildcardType(visit(bound), t.bound);
3630 }
3632 private Type rewriteAsWildcardType(Type bound, TypeVar formal) {
3633 return high ?
3634 makeExtendsWildcard(B(bound), formal) :
3635 makeSuperWildcard(B(bound), formal);
3636 }
3638 Type B(Type t) {
3639 while (t.tag == WILDCARD) {
3640 WildcardType w = (WildcardType)t;
3641 t = high ?
3642 w.getExtendsBound() :
3643 w.getSuperBound();
3644 if (t == null) {
3645 t = high ? syms.objectType : syms.botType;
3646 }
3647 }
3648 return t;
3649 }
3650 }
3653 /**
3654 * Create a wildcard with the given upper (extends) bound; create
3655 * an unbounded wildcard if bound is Object.
3656 *
3657 * @param bound the upper bound
3658 * @param formal the formal type parameter that will be
3659 * substituted by the wildcard
3660 */
3661 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
3662 if (bound == syms.objectType) {
3663 return new WildcardType(syms.objectType,
3664 BoundKind.UNBOUND,
3665 syms.boundClass,
3666 formal);
3667 } else {
3668 return new WildcardType(bound,
3669 BoundKind.EXTENDS,
3670 syms.boundClass,
3671 formal);
3672 }
3673 }
3675 /**
3676 * Create a wildcard with the given lower (super) bound; create an
3677 * unbounded wildcard if bound is bottom (type of {@code null}).
3678 *
3679 * @param bound the lower bound
3680 * @param formal the formal type parameter that will be
3681 * substituted by the wildcard
3682 */
3683 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
3684 if (bound.tag == BOT) {
3685 return new WildcardType(syms.objectType,
3686 BoundKind.UNBOUND,
3687 syms.boundClass,
3688 formal);
3689 } else {
3690 return new WildcardType(bound,
3691 BoundKind.SUPER,
3692 syms.boundClass,
3693 formal);
3694 }
3695 }
3697 /**
3698 * A wrapper for a type that allows use in sets.
3699 */
3700 class SingletonType {
3701 final Type t;
3702 SingletonType(Type t) {
3703 this.t = t;
3704 }
3705 public int hashCode() {
3706 return Types.hashCode(t);
3707 }
3708 public boolean equals(Object obj) {
3709 return (obj instanceof SingletonType) &&
3710 isSameType(t, ((SingletonType)obj).t);
3711 }
3712 public String toString() {
3713 return t.toString();
3714 }
3715 }
3716 // </editor-fold>
3718 // <editor-fold defaultstate="collapsed" desc="Visitors">
3719 /**
3720 * A default visitor for types. All visitor methods except
3721 * visitType are implemented by delegating to visitType. Concrete
3722 * subclasses must provide an implementation of visitType and can
3723 * override other methods as needed.
3724 *
3725 * @param <R> the return type of the operation implemented by this
3726 * visitor; use Void if no return type is needed.
3727 * @param <S> the type of the second argument (the first being the
3728 * type itself) of the operation implemented by this visitor; use
3729 * Void if a second argument is not needed.
3730 */
3731 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
3732 final public R visit(Type t, S s) { return t.accept(this, s); }
3733 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
3734 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
3735 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
3736 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
3737 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
3738 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
3739 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
3740 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
3741 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
3742 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
3743 }
3745 /**
3746 * A default visitor for symbols. All visitor methods except
3747 * visitSymbol are implemented by delegating to visitSymbol. Concrete
3748 * subclasses must provide an implementation of visitSymbol and can
3749 * override other methods as needed.
3750 *
3751 * @param <R> the return type of the operation implemented by this
3752 * visitor; use Void if no return type is needed.
3753 * @param <S> the type of the second argument (the first being the
3754 * symbol itself) of the operation implemented by this visitor; use
3755 * Void if a second argument is not needed.
3756 */
3757 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
3758 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
3759 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
3760 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
3761 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
3762 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
3763 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
3764 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
3765 }
3767 /**
3768 * A <em>simple</em> visitor for types. This visitor is simple as
3769 * captured wildcards, for-all types (generic methods), and
3770 * undetermined type variables (part of inference) are hidden.
3771 * Captured wildcards are hidden by treating them as type
3772 * variables and the rest are hidden by visiting their qtypes.
3773 *
3774 * @param <R> the return type of the operation implemented by this
3775 * visitor; use Void if no return type is needed.
3776 * @param <S> the type of the second argument (the first being the
3777 * type itself) of the operation implemented by this visitor; use
3778 * Void if a second argument is not needed.
3779 */
3780 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
3781 @Override
3782 public R visitCapturedType(CapturedType t, S s) {
3783 return visitTypeVar(t, s);
3784 }
3785 @Override
3786 public R visitForAll(ForAll t, S s) {
3787 return visit(t.qtype, s);
3788 }
3789 @Override
3790 public R visitUndetVar(UndetVar t, S s) {
3791 return visit(t.qtype, s);
3792 }
3793 }
3795 /**
3796 * A plain relation on types. That is a 2-ary function on the
3797 * form Type × Type → Boolean.
3798 * <!-- In plain text: Type x Type -> Boolean -->
3799 */
3800 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
3802 /**
3803 * A convenience visitor for implementing operations that only
3804 * require one argument (the type itself), that is, unary
3805 * operations.
3806 *
3807 * @param <R> the return type of the operation implemented by this
3808 * visitor; use Void if no return type is needed.
3809 */
3810 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
3811 final public R visit(Type t) { return t.accept(this, null); }
3812 }
3814 /**
3815 * A visitor for implementing a mapping from types to types. The
3816 * default behavior of this class is to implement the identity
3817 * mapping (mapping a type to itself). This can be overridden in
3818 * subclasses.
3819 *
3820 * @param <S> the type of the second argument (the first being the
3821 * type itself) of this mapping; use Void if a second argument is
3822 * not needed.
3823 */
3824 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
3825 final public Type visit(Type t) { return t.accept(this, null); }
3826 public Type visitType(Type t, S s) { return t; }
3827 }
3828 // </editor-fold>
3831 // <editor-fold defaultstate="collapsed" desc="Annotation support">
3833 public RetentionPolicy getRetention(Attribute.Compound a) {
3834 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
3835 Attribute.Compound c = a.type.tsym.attribute(syms.retentionType.tsym);
3836 if (c != null) {
3837 Attribute value = c.member(names.value);
3838 if (value != null && value instanceof Attribute.Enum) {
3839 Name levelName = ((Attribute.Enum)value).value.name;
3840 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
3841 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
3842 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
3843 else ;// /* fail soft */ throw new AssertionError(levelName);
3844 }
3845 }
3846 return vis;
3847 }
3848 // </editor-fold>
3849 }
