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src/share/classes/com/sun/tools/javac/code/Types.java@6bb526ccf5ff
src/share/classes/com/sun/tools/javac/code/Types.java
Mon, 23 May 2011 11:55:55 +0100
- author
- mcimadamore
- date
- Mon, 23 May 2011 11:55:55 +0100
- changeset 1015
- 6bb526ccf5ff
- parent 1007
- 95fc7fd39be2
- child 1071
- b86277584776
- permissions
- -rw-r--r--
7046348: Regression: javac complains of missing classfile for a seemingly unrelated interface
Summary: Types.implementation forces unnecessary symbol completion on superinterfaces of a given type
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 convertiable via boxing/unboxing
273 * convertions to s?
274 */
275 public boolean isConvertible(Type t, Type s, Warner warn) {
276 boolean tPrimitive = t.isPrimitive();
277 boolean sPrimitive = s.isPrimitive();
278 if (tPrimitive == sPrimitive) {
279 checkUnsafeVarargsConversion(t, s, warn);
280 return isSubtypeUnchecked(t, s, warn);
281 }
282 if (!allowBoxing) return false;
283 return tPrimitive
284 ? isSubtype(boxedClass(t).type, s)
285 : isSubtype(unboxedType(t), s);
286 }
287 //where
288 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
289 if (t.tag != ARRAY || isReifiable(t)) return;
290 ArrayType from = (ArrayType)t;
291 boolean shouldWarn = false;
292 switch (s.tag) {
293 case ARRAY:
294 ArrayType to = (ArrayType)s;
295 shouldWarn = from.isVarargs() &&
296 !to.isVarargs() &&
297 !isReifiable(from);
298 break;
299 case CLASS:
300 shouldWarn = from.isVarargs() &&
301 isSubtype(from, s);
302 break;
303 }
304 if (shouldWarn) {
305 warn.warn(LintCategory.VARARGS);
306 }
307 }
309 /**
310 * Is t a subtype of or convertiable via boxing/unboxing
311 * convertions to s?
312 */
313 public boolean isConvertible(Type t, Type s) {
314 return isConvertible(t, s, Warner.noWarnings);
315 }
316 // </editor-fold>
318 // <editor-fold defaultstate="collapsed" desc="isSubtype">
319 /**
320 * Is t an unchecked subtype of s?
321 */
322 public boolean isSubtypeUnchecked(Type t, Type s) {
323 return isSubtypeUnchecked(t, s, Warner.noWarnings);
324 }
325 /**
326 * Is t an unchecked subtype of s?
327 */
328 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
329 if (t.tag == ARRAY && s.tag == ARRAY) {
330 if (((ArrayType)t).elemtype.tag <= lastBaseTag) {
331 return isSameType(elemtype(t), elemtype(s));
332 } else {
333 ArrayType from = (ArrayType)t;
334 ArrayType to = (ArrayType)s;
335 if (from.isVarargs() &&
336 !to.isVarargs() &&
337 !isReifiable(from)) {
338 warn.warn(LintCategory.VARARGS);
339 }
340 return isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
341 }
342 } else if (isSubtype(t, s)) {
343 return true;
344 }
345 else if (t.tag == TYPEVAR) {
346 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
347 }
348 else if (s.tag == UNDETVAR) {
349 UndetVar uv = (UndetVar)s;
350 if (uv.inst != null)
351 return isSubtypeUnchecked(t, uv.inst, warn);
352 }
353 else if (!s.isRaw()) {
354 Type t2 = asSuper(t, s.tsym);
355 if (t2 != null && t2.isRaw()) {
356 if (isReifiable(s))
357 warn.silentWarn(LintCategory.UNCHECKED);
358 else
359 warn.warn(LintCategory.UNCHECKED);
360 return true;
361 }
362 }
363 return false;
364 }
366 /**
367 * Is t a subtype of s?<br>
368 * (not defined for Method and ForAll types)
369 */
370 final public boolean isSubtype(Type t, Type s) {
371 return isSubtype(t, s, true);
372 }
373 final public boolean isSubtypeNoCapture(Type t, Type s) {
374 return isSubtype(t, s, false);
375 }
376 public boolean isSubtype(Type t, Type s, boolean capture) {
377 if (t == s)
378 return true;
380 if (s.tag >= firstPartialTag)
381 return isSuperType(s, t);
383 if (s.isCompound()) {
384 for (Type s2 : interfaces(s).prepend(supertype(s))) {
385 if (!isSubtype(t, s2, capture))
386 return false;
387 }
388 return true;
389 }
391 Type lower = lowerBound(s);
392 if (s != lower)
393 return isSubtype(capture ? capture(t) : t, lower, false);
395 return isSubtype.visit(capture ? capture(t) : t, s);
396 }
397 // where
398 private TypeRelation isSubtype = new TypeRelation()
399 {
400 public Boolean visitType(Type t, Type s) {
401 switch (t.tag) {
402 case BYTE: case CHAR:
403 return (t.tag == s.tag ||
404 t.tag + 2 <= s.tag && s.tag <= DOUBLE);
405 case SHORT: case INT: case LONG: case FLOAT: case DOUBLE:
406 return t.tag <= s.tag && s.tag <= DOUBLE;
407 case BOOLEAN: case VOID:
408 return t.tag == s.tag;
409 case TYPEVAR:
410 return isSubtypeNoCapture(t.getUpperBound(), s);
411 case BOT:
412 return
413 s.tag == BOT || s.tag == CLASS ||
414 s.tag == ARRAY || s.tag == TYPEVAR;
415 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
416 case NONE:
417 return false;
418 default:
419 throw new AssertionError("isSubtype " + t.tag);
420 }
421 }
423 private Set<TypePair> cache = new HashSet<TypePair>();
425 private boolean containsTypeRecursive(Type t, Type s) {
426 TypePair pair = new TypePair(t, s);
427 if (cache.add(pair)) {
428 try {
429 return containsType(t.getTypeArguments(),
430 s.getTypeArguments());
431 } finally {
432 cache.remove(pair);
433 }
434 } else {
435 return containsType(t.getTypeArguments(),
436 rewriteSupers(s).getTypeArguments());
437 }
438 }
440 private Type rewriteSupers(Type t) {
441 if (!t.isParameterized())
442 return t;
443 ListBuffer<Type> from = lb();
444 ListBuffer<Type> to = lb();
445 adaptSelf(t, from, to);
446 if (from.isEmpty())
447 return t;
448 ListBuffer<Type> rewrite = lb();
449 boolean changed = false;
450 for (Type orig : to.toList()) {
451 Type s = rewriteSupers(orig);
452 if (s.isSuperBound() && !s.isExtendsBound()) {
453 s = new WildcardType(syms.objectType,
454 BoundKind.UNBOUND,
455 syms.boundClass);
456 changed = true;
457 } else if (s != orig) {
458 s = new WildcardType(upperBound(s),
459 BoundKind.EXTENDS,
460 syms.boundClass);
461 changed = true;
462 }
463 rewrite.append(s);
464 }
465 if (changed)
466 return subst(t.tsym.type, from.toList(), rewrite.toList());
467 else
468 return t;
469 }
471 @Override
472 public Boolean visitClassType(ClassType t, Type s) {
473 Type sup = asSuper(t, s.tsym);
474 return sup != null
475 && sup.tsym == s.tsym
476 // You're not allowed to write
477 // Vector<Object> vec = new Vector<String>();
478 // But with wildcards you can write
479 // Vector<? extends Object> vec = new Vector<String>();
480 // which means that subtype checking must be done
481 // here instead of same-type checking (via containsType).
482 && (!s.isParameterized() || containsTypeRecursive(s, sup))
483 && isSubtypeNoCapture(sup.getEnclosingType(),
484 s.getEnclosingType());
485 }
487 @Override
488 public Boolean visitArrayType(ArrayType t, Type s) {
489 if (s.tag == ARRAY) {
490 if (t.elemtype.tag <= lastBaseTag)
491 return isSameType(t.elemtype, elemtype(s));
492 else
493 return isSubtypeNoCapture(t.elemtype, elemtype(s));
494 }
496 if (s.tag == CLASS) {
497 Name sname = s.tsym.getQualifiedName();
498 return sname == names.java_lang_Object
499 || sname == names.java_lang_Cloneable
500 || sname == names.java_io_Serializable;
501 }
503 return false;
504 }
506 @Override
507 public Boolean visitUndetVar(UndetVar t, Type s) {
508 //todo: test against origin needed? or replace with substitution?
509 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
510 return true;
512 if (t.inst != null)
513 return isSubtypeNoCapture(t.inst, s); // TODO: ", warn"?
515 t.hibounds = t.hibounds.prepend(s);
516 return true;
517 }
519 @Override
520 public Boolean visitErrorType(ErrorType t, Type s) {
521 return true;
522 }
523 };
525 /**
526 * Is t a subtype of every type in given list `ts'?<br>
527 * (not defined for Method and ForAll types)<br>
528 * Allows unchecked conversions.
529 */
530 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
531 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
532 if (!isSubtypeUnchecked(t, l.head, warn))
533 return false;
534 return true;
535 }
537 /**
538 * Are corresponding elements of ts subtypes of ss? If lists are
539 * of different length, return false.
540 */
541 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
542 while (ts.tail != null && ss.tail != null
543 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
544 isSubtype(ts.head, ss.head)) {
545 ts = ts.tail;
546 ss = ss.tail;
547 }
548 return ts.tail == null && ss.tail == null;
549 /*inlined: ts.isEmpty() && ss.isEmpty();*/
550 }
552 /**
553 * Are corresponding elements of ts subtypes of ss, allowing
554 * unchecked conversions? If lists are of different length,
555 * return false.
556 **/
557 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
558 while (ts.tail != null && ss.tail != null
559 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
560 isSubtypeUnchecked(ts.head, ss.head, warn)) {
561 ts = ts.tail;
562 ss = ss.tail;
563 }
564 return ts.tail == null && ss.tail == null;
565 /*inlined: ts.isEmpty() && ss.isEmpty();*/
566 }
567 // </editor-fold>
569 // <editor-fold defaultstate="collapsed" desc="isSuperType">
570 /**
571 * Is t a supertype of s?
572 */
573 public boolean isSuperType(Type t, Type s) {
574 switch (t.tag) {
575 case ERROR:
576 return true;
577 case UNDETVAR: {
578 UndetVar undet = (UndetVar)t;
579 if (t == s ||
580 undet.qtype == s ||
581 s.tag == ERROR ||
582 s.tag == BOT) return true;
583 if (undet.inst != null)
584 return isSubtype(s, undet.inst);
585 undet.lobounds = undet.lobounds.prepend(s);
586 return true;
587 }
588 default:
589 return isSubtype(s, t);
590 }
591 }
592 // </editor-fold>
594 // <editor-fold defaultstate="collapsed" desc="isSameType">
595 /**
596 * Are corresponding elements of the lists the same type? If
597 * lists are of different length, return false.
598 */
599 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
600 while (ts.tail != null && ss.tail != null
601 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
602 isSameType(ts.head, ss.head)) {
603 ts = ts.tail;
604 ss = ss.tail;
605 }
606 return ts.tail == null && ss.tail == null;
607 /*inlined: ts.isEmpty() && ss.isEmpty();*/
608 }
610 /**
611 * Is t the same type as s?
612 */
613 public boolean isSameType(Type t, Type s) {
614 return isSameType.visit(t, s);
615 }
616 // where
617 private TypeRelation isSameType = new TypeRelation() {
619 public Boolean visitType(Type t, Type s) {
620 if (t == s)
621 return true;
623 if (s.tag >= firstPartialTag)
624 return visit(s, t);
626 switch (t.tag) {
627 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
628 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
629 return t.tag == s.tag;
630 case TYPEVAR: {
631 if (s.tag == TYPEVAR) {
632 //type-substitution does not preserve type-var types
633 //check that type var symbols and bounds are indeed the same
634 return t.tsym == s.tsym &&
635 visit(t.getUpperBound(), s.getUpperBound());
636 }
637 else {
638 //special case for s == ? super X, where upper(s) = u
639 //check that u == t, where u has been set by Type.withTypeVar
640 return s.isSuperBound() &&
641 !s.isExtendsBound() &&
642 visit(t, upperBound(s));
643 }
644 }
645 default:
646 throw new AssertionError("isSameType " + t.tag);
647 }
648 }
650 @Override
651 public Boolean visitWildcardType(WildcardType t, Type s) {
652 if (s.tag >= firstPartialTag)
653 return visit(s, t);
654 else
655 return false;
656 }
658 @Override
659 public Boolean visitClassType(ClassType t, Type s) {
660 if (t == s)
661 return true;
663 if (s.tag >= firstPartialTag)
664 return visit(s, t);
666 if (s.isSuperBound() && !s.isExtendsBound())
667 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
669 if (t.isCompound() && s.isCompound()) {
670 if (!visit(supertype(t), supertype(s)))
671 return false;
673 HashSet<SingletonType> set = new HashSet<SingletonType>();
674 for (Type x : interfaces(t))
675 set.add(new SingletonType(x));
676 for (Type x : interfaces(s)) {
677 if (!set.remove(new SingletonType(x)))
678 return false;
679 }
680 return (set.isEmpty());
681 }
682 return t.tsym == s.tsym
683 && visit(t.getEnclosingType(), s.getEnclosingType())
684 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
685 }
687 @Override
688 public Boolean visitArrayType(ArrayType t, Type s) {
689 if (t == s)
690 return true;
692 if (s.tag >= firstPartialTag)
693 return visit(s, t);
695 return s.tag == ARRAY
696 && containsTypeEquivalent(t.elemtype, elemtype(s));
697 }
699 @Override
700 public Boolean visitMethodType(MethodType t, Type s) {
701 // isSameType for methods does not take thrown
702 // exceptions into account!
703 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
704 }
706 @Override
707 public Boolean visitPackageType(PackageType t, Type s) {
708 return t == s;
709 }
711 @Override
712 public Boolean visitForAll(ForAll t, Type s) {
713 if (s.tag != FORALL)
714 return false;
716 ForAll forAll = (ForAll)s;
717 return hasSameBounds(t, forAll)
718 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
719 }
721 @Override
722 public Boolean visitUndetVar(UndetVar t, Type s) {
723 if (s.tag == WILDCARD)
724 // FIXME, this might be leftovers from before capture conversion
725 return false;
727 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
728 return true;
730 if (t.inst != null)
731 return visit(t.inst, s);
733 t.inst = fromUnknownFun.apply(s);
734 for (List<Type> l = t.lobounds; l.nonEmpty(); l = l.tail) {
735 if (!isSubtype(l.head, t.inst))
736 return false;
737 }
738 for (List<Type> l = t.hibounds; l.nonEmpty(); l = l.tail) {
739 if (!isSubtype(t.inst, l.head))
740 return false;
741 }
742 return true;
743 }
745 @Override
746 public Boolean visitErrorType(ErrorType t, Type s) {
747 return true;
748 }
749 };
750 // </editor-fold>
752 // <editor-fold defaultstate="collapsed" desc="fromUnknownFun">
753 /**
754 * A mapping that turns all unknown types in this type to fresh
755 * unknown variables.
756 */
757 public Mapping fromUnknownFun = new Mapping("fromUnknownFun") {
758 public Type apply(Type t) {
759 if (t.tag == UNKNOWN) return new UndetVar(t);
760 else return t.map(this);
761 }
762 };
763 // </editor-fold>
765 // <editor-fold defaultstate="collapsed" desc="Contains Type">
766 public boolean containedBy(Type t, Type s) {
767 switch (t.tag) {
768 case UNDETVAR:
769 if (s.tag == WILDCARD) {
770 UndetVar undetvar = (UndetVar)t;
771 WildcardType wt = (WildcardType)s;
772 switch(wt.kind) {
773 case UNBOUND: //similar to ? extends Object
774 case EXTENDS: {
775 Type bound = upperBound(s);
776 // We should check the new upper bound against any of the
777 // undetvar's lower bounds.
778 for (Type t2 : undetvar.lobounds) {
779 if (!isSubtype(t2, bound))
780 return false;
781 }
782 undetvar.hibounds = undetvar.hibounds.prepend(bound);
783 break;
784 }
785 case SUPER: {
786 Type bound = lowerBound(s);
787 // We should check the new lower bound against any of the
788 // undetvar's lower bounds.
789 for (Type t2 : undetvar.hibounds) {
790 if (!isSubtype(bound, t2))
791 return false;
792 }
793 undetvar.lobounds = undetvar.lobounds.prepend(bound);
794 break;
795 }
796 }
797 return true;
798 } else {
799 return isSameType(t, s);
800 }
801 case ERROR:
802 return true;
803 default:
804 return containsType(s, t);
805 }
806 }
808 boolean containsType(List<Type> ts, List<Type> ss) {
809 while (ts.nonEmpty() && ss.nonEmpty()
810 && containsType(ts.head, ss.head)) {
811 ts = ts.tail;
812 ss = ss.tail;
813 }
814 return ts.isEmpty() && ss.isEmpty();
815 }
817 /**
818 * Check if t contains s.
819 *
820 * <p>T contains S if:
821 *
822 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
823 *
824 * <p>This relation is only used by ClassType.isSubtype(), that
825 * is,
826 *
827 * <p>{@code C<S> <: C<T> if T contains S.}
828 *
829 * <p>Because of F-bounds, this relation can lead to infinite
830 * recursion. Thus we must somehow break that recursion. Notice
831 * that containsType() is only called from ClassType.isSubtype().
832 * Since the arguments have already been checked against their
833 * bounds, we know:
834 *
835 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
836 *
837 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
838 *
839 * @param t a type
840 * @param s a type
841 */
842 public boolean containsType(Type t, Type s) {
843 return containsType.visit(t, s);
844 }
845 // where
846 private TypeRelation containsType = new TypeRelation() {
848 private Type U(Type t) {
849 while (t.tag == WILDCARD) {
850 WildcardType w = (WildcardType)t;
851 if (w.isSuperBound())
852 return w.bound == null ? syms.objectType : w.bound.bound;
853 else
854 t = w.type;
855 }
856 return t;
857 }
859 private Type L(Type t) {
860 while (t.tag == WILDCARD) {
861 WildcardType w = (WildcardType)t;
862 if (w.isExtendsBound())
863 return syms.botType;
864 else
865 t = w.type;
866 }
867 return t;
868 }
870 public Boolean visitType(Type t, Type s) {
871 if (s.tag >= firstPartialTag)
872 return containedBy(s, t);
873 else
874 return isSameType(t, s);
875 }
877 // void debugContainsType(WildcardType t, Type s) {
878 // System.err.println();
879 // System.err.format(" does %s contain %s?%n", t, s);
880 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
881 // upperBound(s), s, t, U(t),
882 // t.isSuperBound()
883 // || isSubtypeNoCapture(upperBound(s), U(t)));
884 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
885 // L(t), t, s, lowerBound(s),
886 // t.isExtendsBound()
887 // || isSubtypeNoCapture(L(t), lowerBound(s)));
888 // System.err.println();
889 // }
891 @Override
892 public Boolean visitWildcardType(WildcardType t, Type s) {
893 if (s.tag >= firstPartialTag)
894 return containedBy(s, t);
895 else {
896 // debugContainsType(t, s);
897 return isSameWildcard(t, s)
898 || isCaptureOf(s, t)
899 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
900 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
901 }
902 }
904 @Override
905 public Boolean visitUndetVar(UndetVar t, Type s) {
906 if (s.tag != WILDCARD)
907 return isSameType(t, s);
908 else
909 return false;
910 }
912 @Override
913 public Boolean visitErrorType(ErrorType t, Type s) {
914 return true;
915 }
916 };
918 public boolean isCaptureOf(Type s, WildcardType t) {
919 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
920 return false;
921 return isSameWildcard(t, ((CapturedType)s).wildcard);
922 }
924 public boolean isSameWildcard(WildcardType t, Type s) {
925 if (s.tag != WILDCARD)
926 return false;
927 WildcardType w = (WildcardType)s;
928 return w.kind == t.kind && w.type == t.type;
929 }
931 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
932 while (ts.nonEmpty() && ss.nonEmpty()
933 && containsTypeEquivalent(ts.head, ss.head)) {
934 ts = ts.tail;
935 ss = ss.tail;
936 }
937 return ts.isEmpty() && ss.isEmpty();
938 }
939 // </editor-fold>
941 // <editor-fold defaultstate="collapsed" desc="isCastable">
942 public boolean isCastable(Type t, Type s) {
943 return isCastable(t, s, Warner.noWarnings);
944 }
946 /**
947 * Is t is castable to s?<br>
948 * s is assumed to be an erased type.<br>
949 * (not defined for Method and ForAll types).
950 */
951 public boolean isCastable(Type t, Type s, Warner warn) {
952 if (t == s)
953 return true;
955 if (t.isPrimitive() != s.isPrimitive())
956 return allowBoxing && (
957 isConvertible(t, s, warn)
958 || (allowObjectToPrimitiveCast &&
959 s.isPrimitive() &&
960 isSubtype(boxedClass(s).type, t)));
961 if (warn != warnStack.head) {
962 try {
963 warnStack = warnStack.prepend(warn);
964 checkUnsafeVarargsConversion(t, s, warn);
965 return isCastable.visit(t,s);
966 } finally {
967 warnStack = warnStack.tail;
968 }
969 } else {
970 return isCastable.visit(t,s);
971 }
972 }
973 // where
974 private TypeRelation isCastable = new TypeRelation() {
976 public Boolean visitType(Type t, Type s) {
977 if (s.tag == ERROR)
978 return true;
980 switch (t.tag) {
981 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
982 case DOUBLE:
983 return s.tag <= DOUBLE;
984 case BOOLEAN:
985 return s.tag == BOOLEAN;
986 case VOID:
987 return false;
988 case BOT:
989 return isSubtype(t, s);
990 default:
991 throw new AssertionError();
992 }
993 }
995 @Override
996 public Boolean visitWildcardType(WildcardType t, Type s) {
997 return isCastable(upperBound(t), s, warnStack.head);
998 }
1000 @Override
1001 public Boolean visitClassType(ClassType t, Type s) {
1002 if (s.tag == ERROR || s.tag == BOT)
1003 return true;
1005 if (s.tag == TYPEVAR) {
1006 if (isCastable(t, s.getUpperBound(), Warner.noWarnings)) {
1007 warnStack.head.warn(LintCategory.UNCHECKED);
1008 return true;
1009 } else {
1010 return false;
1011 }
1012 }
1014 if (t.isCompound()) {
1015 Warner oldWarner = warnStack.head;
1016 warnStack.head = Warner.noWarnings;
1017 if (!visit(supertype(t), s))
1018 return false;
1019 for (Type intf : interfaces(t)) {
1020 if (!visit(intf, s))
1021 return false;
1022 }
1023 if (warnStack.head.hasLint(LintCategory.UNCHECKED))
1024 oldWarner.warn(LintCategory.UNCHECKED);
1025 return true;
1026 }
1028 if (s.isCompound()) {
1029 // call recursively to reuse the above code
1030 return visitClassType((ClassType)s, t);
1031 }
1033 if (s.tag == CLASS || s.tag == ARRAY) {
1034 boolean upcast;
1035 if ((upcast = isSubtype(erasure(t), erasure(s)))
1036 || isSubtype(erasure(s), erasure(t))) {
1037 if (!upcast && s.tag == ARRAY) {
1038 if (!isReifiable(s))
1039 warnStack.head.warn(LintCategory.UNCHECKED);
1040 return true;
1041 } else if (s.isRaw()) {
1042 return true;
1043 } else if (t.isRaw()) {
1044 if (!isUnbounded(s))
1045 warnStack.head.warn(LintCategory.UNCHECKED);
1046 return true;
1047 }
1048 // Assume |a| <: |b|
1049 final Type a = upcast ? t : s;
1050 final Type b = upcast ? s : t;
1051 final boolean HIGH = true;
1052 final boolean LOW = false;
1053 final boolean DONT_REWRITE_TYPEVARS = false;
1054 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1055 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1056 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1057 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1058 Type lowSub = asSub(bLow, aLow.tsym);
1059 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1060 if (highSub == null) {
1061 final boolean REWRITE_TYPEVARS = true;
1062 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1063 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1064 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1065 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1066 lowSub = asSub(bLow, aLow.tsym);
1067 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1068 }
1069 if (highSub != null) {
1070 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1071 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1072 }
1073 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1074 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1075 && !disjointTypes(aLow.allparams(), highSub.allparams())
1076 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1077 if (upcast ? giveWarning(a, b) :
1078 giveWarning(b, a))
1079 warnStack.head.warn(LintCategory.UNCHECKED);
1080 return true;
1081 }
1082 }
1083 if (isReifiable(s))
1084 return isSubtypeUnchecked(a, b);
1085 else
1086 return isSubtypeUnchecked(a, b, warnStack.head);
1087 }
1089 // Sidecast
1090 if (s.tag == CLASS) {
1091 if ((s.tsym.flags() & INTERFACE) != 0) {
1092 return ((t.tsym.flags() & FINAL) == 0)
1093 ? sideCast(t, s, warnStack.head)
1094 : sideCastFinal(t, s, warnStack.head);
1095 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1096 return ((s.tsym.flags() & FINAL) == 0)
1097 ? sideCast(t, s, warnStack.head)
1098 : sideCastFinal(t, s, warnStack.head);
1099 } else {
1100 // unrelated class types
1101 return false;
1102 }
1103 }
1104 }
1105 return false;
1106 }
1108 @Override
1109 public Boolean visitArrayType(ArrayType t, Type s) {
1110 switch (s.tag) {
1111 case ERROR:
1112 case BOT:
1113 return true;
1114 case TYPEVAR:
1115 if (isCastable(s, t, Warner.noWarnings)) {
1116 warnStack.head.warn(LintCategory.UNCHECKED);
1117 return true;
1118 } else {
1119 return false;
1120 }
1121 case CLASS:
1122 return isSubtype(t, s);
1123 case ARRAY:
1124 if (elemtype(t).tag <= lastBaseTag ||
1125 elemtype(s).tag <= lastBaseTag) {
1126 return elemtype(t).tag == elemtype(s).tag;
1127 } else {
1128 return visit(elemtype(t), elemtype(s));
1129 }
1130 default:
1131 return false;
1132 }
1133 }
1135 @Override
1136 public Boolean visitTypeVar(TypeVar t, Type s) {
1137 switch (s.tag) {
1138 case ERROR:
1139 case BOT:
1140 return true;
1141 case TYPEVAR:
1142 if (isSubtype(t, s)) {
1143 return true;
1144 } else if (isCastable(t.bound, s, Warner.noWarnings)) {
1145 warnStack.head.warn(LintCategory.UNCHECKED);
1146 return true;
1147 } else {
1148 return false;
1149 }
1150 default:
1151 return isCastable(t.bound, s, warnStack.head);
1152 }
1153 }
1155 @Override
1156 public Boolean visitErrorType(ErrorType t, Type s) {
1157 return true;
1158 }
1159 };
1160 // </editor-fold>
1162 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1163 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1164 while (ts.tail != null && ss.tail != null) {
1165 if (disjointType(ts.head, ss.head)) return true;
1166 ts = ts.tail;
1167 ss = ss.tail;
1168 }
1169 return false;
1170 }
1172 /**
1173 * Two types or wildcards are considered disjoint if it can be
1174 * proven that no type can be contained in both. It is
1175 * conservative in that it is allowed to say that two types are
1176 * not disjoint, even though they actually are.
1177 *
1178 * The type C<X> is castable to C<Y> exactly if X and Y are not
1179 * disjoint.
1180 */
1181 public boolean disjointType(Type t, Type s) {
1182 return disjointType.visit(t, s);
1183 }
1184 // where
1185 private TypeRelation disjointType = new TypeRelation() {
1187 private Set<TypePair> cache = new HashSet<TypePair>();
1189 public Boolean visitType(Type t, Type s) {
1190 if (s.tag == WILDCARD)
1191 return visit(s, t);
1192 else
1193 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1194 }
1196 private boolean isCastableRecursive(Type t, Type s) {
1197 TypePair pair = new TypePair(t, s);
1198 if (cache.add(pair)) {
1199 try {
1200 return Types.this.isCastable(t, s);
1201 } finally {
1202 cache.remove(pair);
1203 }
1204 } else {
1205 return true;
1206 }
1207 }
1209 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1210 TypePair pair = new TypePair(t, s);
1211 if (cache.add(pair)) {
1212 try {
1213 return Types.this.notSoftSubtype(t, s);
1214 } finally {
1215 cache.remove(pair);
1216 }
1217 } else {
1218 return false;
1219 }
1220 }
1222 @Override
1223 public Boolean visitWildcardType(WildcardType t, Type s) {
1224 if (t.isUnbound())
1225 return false;
1227 if (s.tag != WILDCARD) {
1228 if (t.isExtendsBound())
1229 return notSoftSubtypeRecursive(s, t.type);
1230 else // isSuperBound()
1231 return notSoftSubtypeRecursive(t.type, s);
1232 }
1234 if (s.isUnbound())
1235 return false;
1237 if (t.isExtendsBound()) {
1238 if (s.isExtendsBound())
1239 return !isCastableRecursive(t.type, upperBound(s));
1240 else if (s.isSuperBound())
1241 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1242 } else if (t.isSuperBound()) {
1243 if (s.isExtendsBound())
1244 return notSoftSubtypeRecursive(t.type, upperBound(s));
1245 }
1246 return false;
1247 }
1248 };
1249 // </editor-fold>
1251 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1252 /**
1253 * Returns the lower bounds of the formals of a method.
1254 */
1255 public List<Type> lowerBoundArgtypes(Type t) {
1256 return map(t.getParameterTypes(), lowerBoundMapping);
1257 }
1258 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1259 public Type apply(Type t) {
1260 return lowerBound(t);
1261 }
1262 };
1263 // </editor-fold>
1265 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1266 /**
1267 * This relation answers the question: is impossible that
1268 * something of type `t' can be a subtype of `s'? This is
1269 * different from the question "is `t' not a subtype of `s'?"
1270 * when type variables are involved: Integer is not a subtype of T
1271 * where <T extends Number> but it is not true that Integer cannot
1272 * possibly be a subtype of T.
1273 */
1274 public boolean notSoftSubtype(Type t, Type s) {
1275 if (t == s) return false;
1276 if (t.tag == TYPEVAR) {
1277 TypeVar tv = (TypeVar) t;
1278 return !isCastable(tv.bound,
1279 relaxBound(s),
1280 Warner.noWarnings);
1281 }
1282 if (s.tag != WILDCARD)
1283 s = upperBound(s);
1285 return !isSubtype(t, relaxBound(s));
1286 }
1288 private Type relaxBound(Type t) {
1289 if (t.tag == TYPEVAR) {
1290 while (t.tag == TYPEVAR)
1291 t = t.getUpperBound();
1292 t = rewriteQuantifiers(t, true, true);
1293 }
1294 return t;
1295 }
1296 // </editor-fold>
1298 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1299 public boolean isReifiable(Type t) {
1300 return isReifiable.visit(t);
1301 }
1302 // where
1303 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1305 public Boolean visitType(Type t, Void ignored) {
1306 return true;
1307 }
1309 @Override
1310 public Boolean visitClassType(ClassType t, Void ignored) {
1311 if (t.isCompound())
1312 return false;
1313 else {
1314 if (!t.isParameterized())
1315 return true;
1317 for (Type param : t.allparams()) {
1318 if (!param.isUnbound())
1319 return false;
1320 }
1321 return true;
1322 }
1323 }
1325 @Override
1326 public Boolean visitArrayType(ArrayType t, Void ignored) {
1327 return visit(t.elemtype);
1328 }
1330 @Override
1331 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1332 return false;
1333 }
1334 };
1335 // </editor-fold>
1337 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1338 public boolean isArray(Type t) {
1339 while (t.tag == WILDCARD)
1340 t = upperBound(t);
1341 return t.tag == ARRAY;
1342 }
1344 /**
1345 * The element type of an array.
1346 */
1347 public Type elemtype(Type t) {
1348 switch (t.tag) {
1349 case WILDCARD:
1350 return elemtype(upperBound(t));
1351 case ARRAY:
1352 return ((ArrayType)t).elemtype;
1353 case FORALL:
1354 return elemtype(((ForAll)t).qtype);
1355 case ERROR:
1356 return t;
1357 default:
1358 return null;
1359 }
1360 }
1362 public Type elemtypeOrType(Type t) {
1363 Type elemtype = elemtype(t);
1364 return elemtype != null ?
1365 elemtype :
1366 t;
1367 }
1369 /**
1370 * Mapping to take element type of an arraytype
1371 */
1372 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1373 public Type apply(Type t) { return elemtype(t); }
1374 };
1376 /**
1377 * The number of dimensions of an array type.
1378 */
1379 public int dimensions(Type t) {
1380 int result = 0;
1381 while (t.tag == ARRAY) {
1382 result++;
1383 t = elemtype(t);
1384 }
1385 return result;
1386 }
1387 // </editor-fold>
1389 // <editor-fold defaultstate="collapsed" desc="asSuper">
1390 /**
1391 * Return the (most specific) base type of t that starts with the
1392 * given symbol. If none exists, return null.
1393 *
1394 * @param t a type
1395 * @param sym a symbol
1396 */
1397 public Type asSuper(Type t, Symbol sym) {
1398 return asSuper.visit(t, sym);
1399 }
1400 // where
1401 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1403 public Type visitType(Type t, Symbol sym) {
1404 return null;
1405 }
1407 @Override
1408 public Type visitClassType(ClassType t, Symbol sym) {
1409 if (t.tsym == sym)
1410 return t;
1412 Type st = supertype(t);
1413 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1414 Type x = asSuper(st, sym);
1415 if (x != null)
1416 return x;
1417 }
1418 if ((sym.flags() & INTERFACE) != 0) {
1419 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1420 Type x = asSuper(l.head, sym);
1421 if (x != null)
1422 return x;
1423 }
1424 }
1425 return null;
1426 }
1428 @Override
1429 public Type visitArrayType(ArrayType t, Symbol sym) {
1430 return isSubtype(t, sym.type) ? sym.type : null;
1431 }
1433 @Override
1434 public Type visitTypeVar(TypeVar t, Symbol sym) {
1435 if (t.tsym == sym)
1436 return t;
1437 else
1438 return asSuper(t.bound, sym);
1439 }
1441 @Override
1442 public Type visitErrorType(ErrorType t, Symbol sym) {
1443 return t;
1444 }
1445 };
1447 /**
1448 * Return the base type of t or any of its outer types that starts
1449 * with the given symbol. If none exists, return null.
1450 *
1451 * @param t a type
1452 * @param sym a symbol
1453 */
1454 public Type asOuterSuper(Type t, Symbol sym) {
1455 switch (t.tag) {
1456 case CLASS:
1457 do {
1458 Type s = asSuper(t, sym);
1459 if (s != null) return s;
1460 t = t.getEnclosingType();
1461 } while (t.tag == CLASS);
1462 return null;
1463 case ARRAY:
1464 return isSubtype(t, sym.type) ? sym.type : null;
1465 case TYPEVAR:
1466 return asSuper(t, sym);
1467 case ERROR:
1468 return t;
1469 default:
1470 return null;
1471 }
1472 }
1474 /**
1475 * Return the base type of t or any of its enclosing types that
1476 * starts with the given symbol. If none exists, return null.
1477 *
1478 * @param t a type
1479 * @param sym a symbol
1480 */
1481 public Type asEnclosingSuper(Type t, Symbol sym) {
1482 switch (t.tag) {
1483 case CLASS:
1484 do {
1485 Type s = asSuper(t, sym);
1486 if (s != null) return s;
1487 Type outer = t.getEnclosingType();
1488 t = (outer.tag == CLASS) ? outer :
1489 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1490 Type.noType;
1491 } while (t.tag == CLASS);
1492 return null;
1493 case ARRAY:
1494 return isSubtype(t, sym.type) ? sym.type : null;
1495 case TYPEVAR:
1496 return asSuper(t, sym);
1497 case ERROR:
1498 return t;
1499 default:
1500 return null;
1501 }
1502 }
1503 // </editor-fold>
1505 // <editor-fold defaultstate="collapsed" desc="memberType">
1506 /**
1507 * The type of given symbol, seen as a member of t.
1508 *
1509 * @param t a type
1510 * @param sym a symbol
1511 */
1512 public Type memberType(Type t, Symbol sym) {
1513 return (sym.flags() & STATIC) != 0
1514 ? sym.type
1515 : memberType.visit(t, sym);
1516 }
1517 // where
1518 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1520 public Type visitType(Type t, Symbol sym) {
1521 return sym.type;
1522 }
1524 @Override
1525 public Type visitWildcardType(WildcardType t, Symbol sym) {
1526 return memberType(upperBound(t), sym);
1527 }
1529 @Override
1530 public Type visitClassType(ClassType t, Symbol sym) {
1531 Symbol owner = sym.owner;
1532 long flags = sym.flags();
1533 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1534 Type base = asOuterSuper(t, owner);
1535 //if t is an intersection type T = CT & I1 & I2 ... & In
1536 //its supertypes CT, I1, ... In might contain wildcards
1537 //so we need to go through capture conversion
1538 base = t.isCompound() ? capture(base) : base;
1539 if (base != null) {
1540 List<Type> ownerParams = owner.type.allparams();
1541 List<Type> baseParams = base.allparams();
1542 if (ownerParams.nonEmpty()) {
1543 if (baseParams.isEmpty()) {
1544 // then base is a raw type
1545 return erasure(sym.type);
1546 } else {
1547 return subst(sym.type, ownerParams, baseParams);
1548 }
1549 }
1550 }
1551 }
1552 return sym.type;
1553 }
1555 @Override
1556 public Type visitTypeVar(TypeVar t, Symbol sym) {
1557 return memberType(t.bound, sym);
1558 }
1560 @Override
1561 public Type visitErrorType(ErrorType t, Symbol sym) {
1562 return t;
1563 }
1564 };
1565 // </editor-fold>
1567 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1568 public boolean isAssignable(Type t, Type s) {
1569 return isAssignable(t, s, Warner.noWarnings);
1570 }
1572 /**
1573 * Is t assignable to s?<br>
1574 * Equivalent to subtype except for constant values and raw
1575 * types.<br>
1576 * (not defined for Method and ForAll types)
1577 */
1578 public boolean isAssignable(Type t, Type s, Warner warn) {
1579 if (t.tag == ERROR)
1580 return true;
1581 if (t.tag <= INT && t.constValue() != null) {
1582 int value = ((Number)t.constValue()).intValue();
1583 switch (s.tag) {
1584 case BYTE:
1585 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1586 return true;
1587 break;
1588 case CHAR:
1589 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1590 return true;
1591 break;
1592 case SHORT:
1593 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1594 return true;
1595 break;
1596 case INT:
1597 return true;
1598 case CLASS:
1599 switch (unboxedType(s).tag) {
1600 case BYTE:
1601 case CHAR:
1602 case SHORT:
1603 return isAssignable(t, unboxedType(s), warn);
1604 }
1605 break;
1606 }
1607 }
1608 return isConvertible(t, s, warn);
1609 }
1610 // </editor-fold>
1612 // <editor-fold defaultstate="collapsed" desc="erasure">
1613 /**
1614 * The erasure of t {@code |t|} -- the type that results when all
1615 * type parameters in t are deleted.
1616 */
1617 public Type erasure(Type t) {
1618 return erasure(t, false);
1619 }
1620 //where
1621 private Type erasure(Type t, boolean recurse) {
1622 if (t.tag <= lastBaseTag)
1623 return t; /* fast special case */
1624 else
1625 return erasure.visit(t, recurse);
1626 }
1627 // where
1628 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
1629 public Type visitType(Type t, Boolean recurse) {
1630 if (t.tag <= lastBaseTag)
1631 return t; /*fast special case*/
1632 else
1633 return t.map(recurse ? erasureRecFun : erasureFun);
1634 }
1636 @Override
1637 public Type visitWildcardType(WildcardType t, Boolean recurse) {
1638 return erasure(upperBound(t), recurse);
1639 }
1641 @Override
1642 public Type visitClassType(ClassType t, Boolean recurse) {
1643 Type erased = t.tsym.erasure(Types.this);
1644 if (recurse) {
1645 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
1646 }
1647 return erased;
1648 }
1650 @Override
1651 public Type visitTypeVar(TypeVar t, Boolean recurse) {
1652 return erasure(t.bound, recurse);
1653 }
1655 @Override
1656 public Type visitErrorType(ErrorType t, Boolean recurse) {
1657 return t;
1658 }
1659 };
1661 private Mapping erasureFun = new Mapping ("erasure") {
1662 public Type apply(Type t) { return erasure(t); }
1663 };
1665 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
1666 public Type apply(Type t) { return erasureRecursive(t); }
1667 };
1669 public List<Type> erasure(List<Type> ts) {
1670 return Type.map(ts, erasureFun);
1671 }
1673 public Type erasureRecursive(Type t) {
1674 return erasure(t, true);
1675 }
1677 public List<Type> erasureRecursive(List<Type> ts) {
1678 return Type.map(ts, erasureRecFun);
1679 }
1680 // </editor-fold>
1682 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
1683 /**
1684 * Make a compound type from non-empty list of types
1685 *
1686 * @param bounds the types from which the compound type is formed
1687 * @param supertype is objectType if all bounds are interfaces,
1688 * null otherwise.
1689 */
1690 public Type makeCompoundType(List<Type> bounds,
1691 Type supertype) {
1692 ClassSymbol bc =
1693 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
1694 Type.moreInfo
1695 ? names.fromString(bounds.toString())
1696 : names.empty,
1697 syms.noSymbol);
1698 if (bounds.head.tag == TYPEVAR)
1699 // error condition, recover
1700 bc.erasure_field = syms.objectType;
1701 else
1702 bc.erasure_field = erasure(bounds.head);
1703 bc.members_field = new Scope(bc);
1704 ClassType bt = (ClassType)bc.type;
1705 bt.allparams_field = List.nil();
1706 if (supertype != null) {
1707 bt.supertype_field = supertype;
1708 bt.interfaces_field = bounds;
1709 } else {
1710 bt.supertype_field = bounds.head;
1711 bt.interfaces_field = bounds.tail;
1712 }
1713 Assert.check(bt.supertype_field.tsym.completer != null
1714 || !bt.supertype_field.isInterface(),
1715 bt.supertype_field);
1716 return bt;
1717 }
1719 /**
1720 * Same as {@link #makeCompoundType(List,Type)}, except that the
1721 * second parameter is computed directly. Note that this might
1722 * cause a symbol completion. Hence, this version of
1723 * makeCompoundType may not be called during a classfile read.
1724 */
1725 public Type makeCompoundType(List<Type> bounds) {
1726 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1727 supertype(bounds.head) : null;
1728 return makeCompoundType(bounds, supertype);
1729 }
1731 /**
1732 * A convenience wrapper for {@link #makeCompoundType(List)}; the
1733 * arguments are converted to a list and passed to the other
1734 * method. Note that this might cause a symbol completion.
1735 * Hence, this version of makeCompoundType may not be called
1736 * during a classfile read.
1737 */
1738 public Type makeCompoundType(Type bound1, Type bound2) {
1739 return makeCompoundType(List.of(bound1, bound2));
1740 }
1741 // </editor-fold>
1743 // <editor-fold defaultstate="collapsed" desc="supertype">
1744 public Type supertype(Type t) {
1745 return supertype.visit(t);
1746 }
1747 // where
1748 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
1750 public Type visitType(Type t, Void ignored) {
1751 // A note on wildcards: there is no good way to
1752 // determine a supertype for a super bounded wildcard.
1753 return null;
1754 }
1756 @Override
1757 public Type visitClassType(ClassType t, Void ignored) {
1758 if (t.supertype_field == null) {
1759 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
1760 // An interface has no superclass; its supertype is Object.
1761 if (t.isInterface())
1762 supertype = ((ClassType)t.tsym.type).supertype_field;
1763 if (t.supertype_field == null) {
1764 List<Type> actuals = classBound(t).allparams();
1765 List<Type> formals = t.tsym.type.allparams();
1766 if (t.hasErasedSupertypes()) {
1767 t.supertype_field = erasureRecursive(supertype);
1768 } else if (formals.nonEmpty()) {
1769 t.supertype_field = subst(supertype, formals, actuals);
1770 }
1771 else {
1772 t.supertype_field = supertype;
1773 }
1774 }
1775 }
1776 return t.supertype_field;
1777 }
1779 /**
1780 * The supertype is always a class type. If the type
1781 * variable's bounds start with a class type, this is also
1782 * the supertype. Otherwise, the supertype is
1783 * java.lang.Object.
1784 */
1785 @Override
1786 public Type visitTypeVar(TypeVar t, Void ignored) {
1787 if (t.bound.tag == TYPEVAR ||
1788 (!t.bound.isCompound() && !t.bound.isInterface())) {
1789 return t.bound;
1790 } else {
1791 return supertype(t.bound);
1792 }
1793 }
1795 @Override
1796 public Type visitArrayType(ArrayType t, Void ignored) {
1797 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
1798 return arraySuperType();
1799 else
1800 return new ArrayType(supertype(t.elemtype), t.tsym);
1801 }
1803 @Override
1804 public Type visitErrorType(ErrorType t, Void ignored) {
1805 return t;
1806 }
1807 };
1808 // </editor-fold>
1810 // <editor-fold defaultstate="collapsed" desc="interfaces">
1811 /**
1812 * Return the interfaces implemented by this class.
1813 */
1814 public List<Type> interfaces(Type t) {
1815 return interfaces.visit(t);
1816 }
1817 // where
1818 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
1820 public List<Type> visitType(Type t, Void ignored) {
1821 return List.nil();
1822 }
1824 @Override
1825 public List<Type> visitClassType(ClassType t, Void ignored) {
1826 if (t.interfaces_field == null) {
1827 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
1828 if (t.interfaces_field == null) {
1829 // If t.interfaces_field is null, then t must
1830 // be a parameterized type (not to be confused
1831 // with a generic type declaration).
1832 // Terminology:
1833 // Parameterized type: List<String>
1834 // Generic type declaration: class List<E> { ... }
1835 // So t corresponds to List<String> and
1836 // t.tsym.type corresponds to List<E>.
1837 // The reason t must be parameterized type is
1838 // that completion will happen as a side
1839 // effect of calling
1840 // ClassSymbol.getInterfaces. Since
1841 // t.interfaces_field is null after
1842 // completion, we can assume that t is not the
1843 // type of a class/interface declaration.
1844 Assert.check(t != t.tsym.type, t);
1845 List<Type> actuals = t.allparams();
1846 List<Type> formals = t.tsym.type.allparams();
1847 if (t.hasErasedSupertypes()) {
1848 t.interfaces_field = erasureRecursive(interfaces);
1849 } else if (formals.nonEmpty()) {
1850 t.interfaces_field =
1851 upperBounds(subst(interfaces, formals, actuals));
1852 }
1853 else {
1854 t.interfaces_field = interfaces;
1855 }
1856 }
1857 }
1858 return t.interfaces_field;
1859 }
1861 @Override
1862 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
1863 if (t.bound.isCompound())
1864 return interfaces(t.bound);
1866 if (t.bound.isInterface())
1867 return List.of(t.bound);
1869 return List.nil();
1870 }
1871 };
1872 // </editor-fold>
1874 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
1875 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
1877 public boolean isDerivedRaw(Type t) {
1878 Boolean result = isDerivedRawCache.get(t);
1879 if (result == null) {
1880 result = isDerivedRawInternal(t);
1881 isDerivedRawCache.put(t, result);
1882 }
1883 return result;
1884 }
1886 public boolean isDerivedRawInternal(Type t) {
1887 if (t.isErroneous())
1888 return false;
1889 return
1890 t.isRaw() ||
1891 supertype(t) != null && isDerivedRaw(supertype(t)) ||
1892 isDerivedRaw(interfaces(t));
1893 }
1895 public boolean isDerivedRaw(List<Type> ts) {
1896 List<Type> l = ts;
1897 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
1898 return l.nonEmpty();
1899 }
1900 // </editor-fold>
1902 // <editor-fold defaultstate="collapsed" desc="setBounds">
1903 /**
1904 * Set the bounds field of the given type variable to reflect a
1905 * (possibly multiple) list of bounds.
1906 * @param t a type variable
1907 * @param bounds the bounds, must be nonempty
1908 * @param supertype is objectType if all bounds are interfaces,
1909 * null otherwise.
1910 */
1911 public void setBounds(TypeVar t, List<Type> bounds, Type supertype) {
1912 if (bounds.tail.isEmpty())
1913 t.bound = bounds.head;
1914 else
1915 t.bound = makeCompoundType(bounds, supertype);
1916 t.rank_field = -1;
1917 }
1919 /**
1920 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
1921 * third parameter is computed directly, as follows: if all
1922 * all bounds are interface types, the computed supertype is Object,
1923 * otherwise the supertype is simply left null (in this case, the supertype
1924 * is assumed to be the head of the bound list passed as second argument).
1925 * Note that this check might cause a symbol completion. Hence, this version of
1926 * setBounds may not be called during a classfile read.
1927 */
1928 public void setBounds(TypeVar t, List<Type> bounds) {
1929 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1930 syms.objectType : null;
1931 setBounds(t, bounds, supertype);
1932 t.rank_field = -1;
1933 }
1934 // </editor-fold>
1936 // <editor-fold defaultstate="collapsed" desc="getBounds">
1937 /**
1938 * Return list of bounds of the given type variable.
1939 */
1940 public List<Type> getBounds(TypeVar t) {
1941 if (t.bound.isErroneous() || !t.bound.isCompound())
1942 return List.of(t.bound);
1943 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
1944 return interfaces(t).prepend(supertype(t));
1945 else
1946 // No superclass was given in bounds.
1947 // In this case, supertype is Object, erasure is first interface.
1948 return interfaces(t);
1949 }
1950 // </editor-fold>
1952 // <editor-fold defaultstate="collapsed" desc="classBound">
1953 /**
1954 * If the given type is a (possibly selected) type variable,
1955 * return the bounding class of this type, otherwise return the
1956 * type itself.
1957 */
1958 public Type classBound(Type t) {
1959 return classBound.visit(t);
1960 }
1961 // where
1962 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
1964 public Type visitType(Type t, Void ignored) {
1965 return t;
1966 }
1968 @Override
1969 public Type visitClassType(ClassType t, Void ignored) {
1970 Type outer1 = classBound(t.getEnclosingType());
1971 if (outer1 != t.getEnclosingType())
1972 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
1973 else
1974 return t;
1975 }
1977 @Override
1978 public Type visitTypeVar(TypeVar t, Void ignored) {
1979 return classBound(supertype(t));
1980 }
1982 @Override
1983 public Type visitErrorType(ErrorType t, Void ignored) {
1984 return t;
1985 }
1986 };
1987 // </editor-fold>
1989 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
1990 /**
1991 * Returns true iff the first signature is a <em>sub
1992 * signature</em> of the other. This is <b>not</b> an equivalence
1993 * relation.
1994 *
1995 * @jls section 8.4.2.
1996 * @see #overrideEquivalent(Type t, Type s)
1997 * @param t first signature (possibly raw).
1998 * @param s second signature (could be subjected to erasure).
1999 * @return true if t is a sub signature of s.
2000 */
2001 public boolean isSubSignature(Type t, Type s) {
2002 return isSubSignature(t, s, true);
2003 }
2005 public boolean isSubSignature(Type t, Type s, boolean strict) {
2006 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
2007 }
2009 /**
2010 * Returns true iff these signatures are related by <em>override
2011 * equivalence</em>. This is the natural extension of
2012 * isSubSignature to an equivalence relation.
2013 *
2014 * @jls section 8.4.2.
2015 * @see #isSubSignature(Type t, Type s)
2016 * @param t a signature (possible raw, could be subjected to
2017 * erasure).
2018 * @param s a signature (possible raw, could be subjected to
2019 * erasure).
2020 * @return true if either argument is a sub signature of the other.
2021 */
2022 public boolean overrideEquivalent(Type t, Type s) {
2023 return hasSameArgs(t, s) ||
2024 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2025 }
2027 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2028 class ImplementationCache {
2030 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
2031 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
2033 class Entry {
2034 final MethodSymbol cachedImpl;
2035 final Filter<Symbol> implFilter;
2036 final boolean checkResult;
2037 final int prevMark;
2039 public Entry(MethodSymbol cachedImpl,
2040 Filter<Symbol> scopeFilter,
2041 boolean checkResult,
2042 int prevMark) {
2043 this.cachedImpl = cachedImpl;
2044 this.implFilter = scopeFilter;
2045 this.checkResult = checkResult;
2046 this.prevMark = prevMark;
2047 }
2049 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
2050 return this.implFilter == scopeFilter &&
2051 this.checkResult == checkResult &&
2052 this.prevMark == mark;
2053 }
2054 }
2056 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2057 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2058 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2059 if (cache == null) {
2060 cache = new HashMap<TypeSymbol, Entry>();
2061 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2062 }
2063 Entry e = cache.get(origin);
2064 CompoundScope members = membersClosure(origin.type, true);
2065 if (e == null ||
2066 !e.matches(implFilter, checkResult, members.getMark())) {
2067 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
2068 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
2069 return impl;
2070 }
2071 else {
2072 return e.cachedImpl;
2073 }
2074 }
2076 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2077 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = supertype(t)) {
2078 while (t.tag == TYPEVAR)
2079 t = t.getUpperBound();
2080 TypeSymbol c = t.tsym;
2081 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2082 e.scope != null;
2083 e = e.next(implFilter)) {
2084 if (e.sym != null &&
2085 e.sym.overrides(ms, origin, Types.this, checkResult))
2086 return (MethodSymbol)e.sym;
2087 }
2088 }
2089 return null;
2090 }
2091 }
2093 private ImplementationCache implCache = new ImplementationCache();
2095 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2096 return implCache.get(ms, origin, checkResult, implFilter);
2097 }
2098 // </editor-fold>
2100 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2101 class MembersClosureCache extends SimpleVisitor<CompoundScope, Boolean> {
2103 private WeakHashMap<TypeSymbol, Entry> _map =
2104 new WeakHashMap<TypeSymbol, Entry>();
2106 class Entry {
2107 final boolean skipInterfaces;
2108 final CompoundScope compoundScope;
2110 public Entry(boolean skipInterfaces, CompoundScope compoundScope) {
2111 this.skipInterfaces = skipInterfaces;
2112 this.compoundScope = compoundScope;
2113 }
2115 boolean matches(boolean skipInterfaces) {
2116 return this.skipInterfaces == skipInterfaces;
2117 }
2118 }
2120 /** members closure visitor methods **/
2122 public CompoundScope visitType(Type t, Boolean skipInterface) {
2123 return null;
2124 }
2126 @Override
2127 public CompoundScope visitClassType(ClassType t, Boolean skipInterface) {
2128 ClassSymbol csym = (ClassSymbol)t.tsym;
2129 Entry e = _map.get(csym);
2130 if (e == null || !e.matches(skipInterface)) {
2131 CompoundScope membersClosure = new CompoundScope(csym);
2132 if (!skipInterface) {
2133 for (Type i : interfaces(t)) {
2134 membersClosure.addSubScope(visit(i, skipInterface));
2135 }
2136 }
2137 membersClosure.addSubScope(visit(supertype(t), skipInterface));
2138 membersClosure.addSubScope(csym.members());
2139 e = new Entry(skipInterface, membersClosure);
2140 _map.put(csym, e);
2141 }
2142 return e.compoundScope;
2143 }
2145 @Override
2146 public CompoundScope visitTypeVar(TypeVar t, Boolean skipInterface) {
2147 return visit(t.getUpperBound(), skipInterface);
2148 }
2149 }
2151 private MembersClosureCache membersCache = new MembersClosureCache();
2153 public CompoundScope membersClosure(Type site, boolean skipInterface) {
2154 return membersCache.visit(site, skipInterface);
2155 }
2156 // </editor-fold>
2158 /**
2159 * Does t have the same arguments as s? It is assumed that both
2160 * types are (possibly polymorphic) method types. Monomorphic
2161 * method types "have the same arguments", if their argument lists
2162 * are equal. Polymorphic method types "have the same arguments",
2163 * if they have the same arguments after renaming all type
2164 * variables of one to corresponding type variables in the other,
2165 * where correspondence is by position in the type parameter list.
2166 */
2167 public boolean hasSameArgs(Type t, Type s) {
2168 return hasSameArgs(t, s, true);
2169 }
2171 public boolean hasSameArgs(Type t, Type s, boolean strict) {
2172 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
2173 }
2175 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
2176 return hasSameArgs.visit(t, s);
2177 }
2178 // where
2179 private class HasSameArgs extends TypeRelation {
2181 boolean strict;
2183 public HasSameArgs(boolean strict) {
2184 this.strict = strict;
2185 }
2187 public Boolean visitType(Type t, Type s) {
2188 throw new AssertionError();
2189 }
2191 @Override
2192 public Boolean visitMethodType(MethodType t, Type s) {
2193 return s.tag == METHOD
2194 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2195 }
2197 @Override
2198 public Boolean visitForAll(ForAll t, Type s) {
2199 if (s.tag != FORALL)
2200 return strict ? false : visitMethodType(t.asMethodType(), s);
2202 ForAll forAll = (ForAll)s;
2203 return hasSameBounds(t, forAll)
2204 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2205 }
2207 @Override
2208 public Boolean visitErrorType(ErrorType t, Type s) {
2209 return false;
2210 }
2211 };
2213 TypeRelation hasSameArgs_strict = new HasSameArgs(true);
2214 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
2216 // </editor-fold>
2218 // <editor-fold defaultstate="collapsed" desc="subst">
2219 public List<Type> subst(List<Type> ts,
2220 List<Type> from,
2221 List<Type> to) {
2222 return new Subst(from, to).subst(ts);
2223 }
2225 /**
2226 * Substitute all occurrences of a type in `from' with the
2227 * corresponding type in `to' in 't'. Match lists `from' and `to'
2228 * from the right: If lists have different length, discard leading
2229 * elements of the longer list.
2230 */
2231 public Type subst(Type t, List<Type> from, List<Type> to) {
2232 return new Subst(from, to).subst(t);
2233 }
2235 private class Subst extends UnaryVisitor<Type> {
2236 List<Type> from;
2237 List<Type> to;
2239 public Subst(List<Type> from, List<Type> to) {
2240 int fromLength = from.length();
2241 int toLength = to.length();
2242 while (fromLength > toLength) {
2243 fromLength--;
2244 from = from.tail;
2245 }
2246 while (fromLength < toLength) {
2247 toLength--;
2248 to = to.tail;
2249 }
2250 this.from = from;
2251 this.to = to;
2252 }
2254 Type subst(Type t) {
2255 if (from.tail == null)
2256 return t;
2257 else
2258 return visit(t);
2259 }
2261 List<Type> subst(List<Type> ts) {
2262 if (from.tail == null)
2263 return ts;
2264 boolean wild = false;
2265 if (ts.nonEmpty() && from.nonEmpty()) {
2266 Type head1 = subst(ts.head);
2267 List<Type> tail1 = subst(ts.tail);
2268 if (head1 != ts.head || tail1 != ts.tail)
2269 return tail1.prepend(head1);
2270 }
2271 return ts;
2272 }
2274 public Type visitType(Type t, Void ignored) {
2275 return t;
2276 }
2278 @Override
2279 public Type visitMethodType(MethodType t, Void ignored) {
2280 List<Type> argtypes = subst(t.argtypes);
2281 Type restype = subst(t.restype);
2282 List<Type> thrown = subst(t.thrown);
2283 if (argtypes == t.argtypes &&
2284 restype == t.restype &&
2285 thrown == t.thrown)
2286 return t;
2287 else
2288 return new MethodType(argtypes, restype, thrown, t.tsym);
2289 }
2291 @Override
2292 public Type visitTypeVar(TypeVar t, Void ignored) {
2293 for (List<Type> from = this.from, to = this.to;
2294 from.nonEmpty();
2295 from = from.tail, to = to.tail) {
2296 if (t == from.head) {
2297 return to.head.withTypeVar(t);
2298 }
2299 }
2300 return t;
2301 }
2303 @Override
2304 public Type visitClassType(ClassType t, Void ignored) {
2305 if (!t.isCompound()) {
2306 List<Type> typarams = t.getTypeArguments();
2307 List<Type> typarams1 = subst(typarams);
2308 Type outer = t.getEnclosingType();
2309 Type outer1 = subst(outer);
2310 if (typarams1 == typarams && outer1 == outer)
2311 return t;
2312 else
2313 return new ClassType(outer1, typarams1, t.tsym);
2314 } else {
2315 Type st = subst(supertype(t));
2316 List<Type> is = upperBounds(subst(interfaces(t)));
2317 if (st == supertype(t) && is == interfaces(t))
2318 return t;
2319 else
2320 return makeCompoundType(is.prepend(st));
2321 }
2322 }
2324 @Override
2325 public Type visitWildcardType(WildcardType t, Void ignored) {
2326 Type bound = t.type;
2327 if (t.kind != BoundKind.UNBOUND)
2328 bound = subst(bound);
2329 if (bound == t.type) {
2330 return t;
2331 } else {
2332 if (t.isExtendsBound() && bound.isExtendsBound())
2333 bound = upperBound(bound);
2334 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2335 }
2336 }
2338 @Override
2339 public Type visitArrayType(ArrayType t, Void ignored) {
2340 Type elemtype = subst(t.elemtype);
2341 if (elemtype == t.elemtype)
2342 return t;
2343 else
2344 return new ArrayType(upperBound(elemtype), t.tsym);
2345 }
2347 @Override
2348 public Type visitForAll(ForAll t, Void ignored) {
2349 if (Type.containsAny(to, t.tvars)) {
2350 //perform alpha-renaming of free-variables in 't'
2351 //if 'to' types contain variables that are free in 't'
2352 List<Type> freevars = newInstances(t.tvars);
2353 t = new ForAll(freevars,
2354 Types.this.subst(t.qtype, t.tvars, freevars));
2355 }
2356 List<Type> tvars1 = substBounds(t.tvars, from, to);
2357 Type qtype1 = subst(t.qtype);
2358 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2359 return t;
2360 } else if (tvars1 == t.tvars) {
2361 return new ForAll(tvars1, qtype1);
2362 } else {
2363 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2364 }
2365 }
2367 @Override
2368 public Type visitErrorType(ErrorType t, Void ignored) {
2369 return t;
2370 }
2371 }
2373 public List<Type> substBounds(List<Type> tvars,
2374 List<Type> from,
2375 List<Type> to) {
2376 if (tvars.isEmpty())
2377 return tvars;
2378 ListBuffer<Type> newBoundsBuf = lb();
2379 boolean changed = false;
2380 // calculate new bounds
2381 for (Type t : tvars) {
2382 TypeVar tv = (TypeVar) t;
2383 Type bound = subst(tv.bound, from, to);
2384 if (bound != tv.bound)
2385 changed = true;
2386 newBoundsBuf.append(bound);
2387 }
2388 if (!changed)
2389 return tvars;
2390 ListBuffer<Type> newTvars = lb();
2391 // create new type variables without bounds
2392 for (Type t : tvars) {
2393 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2394 }
2395 // the new bounds should use the new type variables in place
2396 // of the old
2397 List<Type> newBounds = newBoundsBuf.toList();
2398 from = tvars;
2399 to = newTvars.toList();
2400 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2401 newBounds.head = subst(newBounds.head, from, to);
2402 }
2403 newBounds = newBoundsBuf.toList();
2404 // set the bounds of new type variables to the new bounds
2405 for (Type t : newTvars.toList()) {
2406 TypeVar tv = (TypeVar) t;
2407 tv.bound = newBounds.head;
2408 newBounds = newBounds.tail;
2409 }
2410 return newTvars.toList();
2411 }
2413 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2414 Type bound1 = subst(t.bound, from, to);
2415 if (bound1 == t.bound)
2416 return t;
2417 else {
2418 // create new type variable without bounds
2419 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2420 // the new bound should use the new type variable in place
2421 // of the old
2422 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2423 return tv;
2424 }
2425 }
2426 // </editor-fold>
2428 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2429 /**
2430 * Does t have the same bounds for quantified variables as s?
2431 */
2432 boolean hasSameBounds(ForAll t, ForAll s) {
2433 List<Type> l1 = t.tvars;
2434 List<Type> l2 = s.tvars;
2435 while (l1.nonEmpty() && l2.nonEmpty() &&
2436 isSameType(l1.head.getUpperBound(),
2437 subst(l2.head.getUpperBound(),
2438 s.tvars,
2439 t.tvars))) {
2440 l1 = l1.tail;
2441 l2 = l2.tail;
2442 }
2443 return l1.isEmpty() && l2.isEmpty();
2444 }
2445 // </editor-fold>
2447 // <editor-fold defaultstate="collapsed" desc="newInstances">
2448 /** Create new vector of type variables from list of variables
2449 * changing all recursive bounds from old to new list.
2450 */
2451 public List<Type> newInstances(List<Type> tvars) {
2452 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2453 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2454 TypeVar tv = (TypeVar) l.head;
2455 tv.bound = subst(tv.bound, tvars, tvars1);
2456 }
2457 return tvars1;
2458 }
2459 static private Mapping newInstanceFun = new Mapping("newInstanceFun") {
2460 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2461 };
2462 // </editor-fold>
2464 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
2465 return original.accept(methodWithParameters, newParams);
2466 }
2467 // where
2468 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
2469 public Type visitType(Type t, List<Type> newParams) {
2470 throw new IllegalArgumentException("Not a method type: " + t);
2471 }
2472 public Type visitMethodType(MethodType t, List<Type> newParams) {
2473 return new MethodType(newParams, t.restype, t.thrown, t.tsym);
2474 }
2475 public Type visitForAll(ForAll t, List<Type> newParams) {
2476 return new ForAll(t.tvars, t.qtype.accept(this, newParams));
2477 }
2478 };
2480 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
2481 return original.accept(methodWithThrown, newThrown);
2482 }
2483 // where
2484 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
2485 public Type visitType(Type t, List<Type> newThrown) {
2486 throw new IllegalArgumentException("Not a method type: " + t);
2487 }
2488 public Type visitMethodType(MethodType t, List<Type> newThrown) {
2489 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
2490 }
2491 public Type visitForAll(ForAll t, List<Type> newThrown) {
2492 return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
2493 }
2494 };
2496 public Type createMethodTypeWithReturn(Type original, Type newReturn) {
2497 return original.accept(methodWithReturn, newReturn);
2498 }
2499 // where
2500 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
2501 public Type visitType(Type t, Type newReturn) {
2502 throw new IllegalArgumentException("Not a method type: " + t);
2503 }
2504 public Type visitMethodType(MethodType t, Type newReturn) {
2505 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym);
2506 }
2507 public Type visitForAll(ForAll t, Type newReturn) {
2508 return new ForAll(t.tvars, t.qtype.accept(this, newReturn));
2509 }
2510 };
2512 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2513 public Type createErrorType(Type originalType) {
2514 return new ErrorType(originalType, syms.errSymbol);
2515 }
2517 public Type createErrorType(ClassSymbol c, Type originalType) {
2518 return new ErrorType(c, originalType);
2519 }
2521 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
2522 return new ErrorType(name, container, originalType);
2523 }
2524 // </editor-fold>
2526 // <editor-fold defaultstate="collapsed" desc="rank">
2527 /**
2528 * The rank of a class is the length of the longest path between
2529 * the class and java.lang.Object in the class inheritance
2530 * graph. Undefined for all but reference types.
2531 */
2532 public int rank(Type t) {
2533 switch(t.tag) {
2534 case CLASS: {
2535 ClassType cls = (ClassType)t;
2536 if (cls.rank_field < 0) {
2537 Name fullname = cls.tsym.getQualifiedName();
2538 if (fullname == names.java_lang_Object)
2539 cls.rank_field = 0;
2540 else {
2541 int r = rank(supertype(cls));
2542 for (List<Type> l = interfaces(cls);
2543 l.nonEmpty();
2544 l = l.tail) {
2545 if (rank(l.head) > r)
2546 r = rank(l.head);
2547 }
2548 cls.rank_field = r + 1;
2549 }
2550 }
2551 return cls.rank_field;
2552 }
2553 case TYPEVAR: {
2554 TypeVar tvar = (TypeVar)t;
2555 if (tvar.rank_field < 0) {
2556 int r = rank(supertype(tvar));
2557 for (List<Type> l = interfaces(tvar);
2558 l.nonEmpty();
2559 l = l.tail) {
2560 if (rank(l.head) > r) r = rank(l.head);
2561 }
2562 tvar.rank_field = r + 1;
2563 }
2564 return tvar.rank_field;
2565 }
2566 case ERROR:
2567 return 0;
2568 default:
2569 throw new AssertionError();
2570 }
2571 }
2572 // </editor-fold>
2574 /**
2575 * Helper method for generating a string representation of a given type
2576 * accordingly to a given locale
2577 */
2578 public String toString(Type t, Locale locale) {
2579 return Printer.createStandardPrinter(messages).visit(t, locale);
2580 }
2582 /**
2583 * Helper method for generating a string representation of a given type
2584 * accordingly to a given locale
2585 */
2586 public String toString(Symbol t, Locale locale) {
2587 return Printer.createStandardPrinter(messages).visit(t, locale);
2588 }
2590 // <editor-fold defaultstate="collapsed" desc="toString">
2591 /**
2592 * This toString is slightly more descriptive than the one on Type.
2593 *
2594 * @deprecated Types.toString(Type t, Locale l) provides better support
2595 * for localization
2596 */
2597 @Deprecated
2598 public String toString(Type t) {
2599 if (t.tag == FORALL) {
2600 ForAll forAll = (ForAll)t;
2601 return typaramsString(forAll.tvars) + forAll.qtype;
2602 }
2603 return "" + t;
2604 }
2605 // where
2606 private String typaramsString(List<Type> tvars) {
2607 StringBuilder s = new StringBuilder();
2608 s.append('<');
2609 boolean first = true;
2610 for (Type t : tvars) {
2611 if (!first) s.append(", ");
2612 first = false;
2613 appendTyparamString(((TypeVar)t), s);
2614 }
2615 s.append('>');
2616 return s.toString();
2617 }
2618 private void appendTyparamString(TypeVar t, StringBuilder buf) {
2619 buf.append(t);
2620 if (t.bound == null ||
2621 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
2622 return;
2623 buf.append(" extends "); // Java syntax; no need for i18n
2624 Type bound = t.bound;
2625 if (!bound.isCompound()) {
2626 buf.append(bound);
2627 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
2628 buf.append(supertype(t));
2629 for (Type intf : interfaces(t)) {
2630 buf.append('&');
2631 buf.append(intf);
2632 }
2633 } else {
2634 // No superclass was given in bounds.
2635 // In this case, supertype is Object, erasure is first interface.
2636 boolean first = true;
2637 for (Type intf : interfaces(t)) {
2638 if (!first) buf.append('&');
2639 first = false;
2640 buf.append(intf);
2641 }
2642 }
2643 }
2644 // </editor-fold>
2646 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
2647 /**
2648 * A cache for closures.
2649 *
2650 * <p>A closure is a list of all the supertypes and interfaces of
2651 * a class or interface type, ordered by ClassSymbol.precedes
2652 * (that is, subclasses come first, arbitrary but fixed
2653 * otherwise).
2654 */
2655 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
2657 /**
2658 * Returns the closure of a class or interface type.
2659 */
2660 public List<Type> closure(Type t) {
2661 List<Type> cl = closureCache.get(t);
2662 if (cl == null) {
2663 Type st = supertype(t);
2664 if (!t.isCompound()) {
2665 if (st.tag == CLASS) {
2666 cl = insert(closure(st), t);
2667 } else if (st.tag == TYPEVAR) {
2668 cl = closure(st).prepend(t);
2669 } else {
2670 cl = List.of(t);
2671 }
2672 } else {
2673 cl = closure(supertype(t));
2674 }
2675 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
2676 cl = union(cl, closure(l.head));
2677 closureCache.put(t, cl);
2678 }
2679 return cl;
2680 }
2682 /**
2683 * Insert a type in a closure
2684 */
2685 public List<Type> insert(List<Type> cl, Type t) {
2686 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
2687 return cl.prepend(t);
2688 } else if (cl.head.tsym.precedes(t.tsym, this)) {
2689 return insert(cl.tail, t).prepend(cl.head);
2690 } else {
2691 return cl;
2692 }
2693 }
2695 /**
2696 * Form the union of two closures
2697 */
2698 public List<Type> union(List<Type> cl1, List<Type> cl2) {
2699 if (cl1.isEmpty()) {
2700 return cl2;
2701 } else if (cl2.isEmpty()) {
2702 return cl1;
2703 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
2704 return union(cl1.tail, cl2).prepend(cl1.head);
2705 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
2706 return union(cl1, cl2.tail).prepend(cl2.head);
2707 } else {
2708 return union(cl1.tail, cl2.tail).prepend(cl1.head);
2709 }
2710 }
2712 /**
2713 * Intersect two closures
2714 */
2715 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
2716 if (cl1 == cl2)
2717 return cl1;
2718 if (cl1.isEmpty() || cl2.isEmpty())
2719 return List.nil();
2720 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
2721 return intersect(cl1.tail, cl2);
2722 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
2723 return intersect(cl1, cl2.tail);
2724 if (isSameType(cl1.head, cl2.head))
2725 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
2726 if (cl1.head.tsym == cl2.head.tsym &&
2727 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
2728 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
2729 Type merge = merge(cl1.head,cl2.head);
2730 return intersect(cl1.tail, cl2.tail).prepend(merge);
2731 }
2732 if (cl1.head.isRaw() || cl2.head.isRaw())
2733 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
2734 }
2735 return intersect(cl1.tail, cl2.tail);
2736 }
2737 // where
2738 class TypePair {
2739 final Type t1;
2740 final Type t2;
2741 TypePair(Type t1, Type t2) {
2742 this.t1 = t1;
2743 this.t2 = t2;
2744 }
2745 @Override
2746 public int hashCode() {
2747 return 127 * Types.hashCode(t1) + Types.hashCode(t2);
2748 }
2749 @Override
2750 public boolean equals(Object obj) {
2751 if (!(obj instanceof TypePair))
2752 return false;
2753 TypePair typePair = (TypePair)obj;
2754 return isSameType(t1, typePair.t1)
2755 && isSameType(t2, typePair.t2);
2756 }
2757 }
2758 Set<TypePair> mergeCache = new HashSet<TypePair>();
2759 private Type merge(Type c1, Type c2) {
2760 ClassType class1 = (ClassType) c1;
2761 List<Type> act1 = class1.getTypeArguments();
2762 ClassType class2 = (ClassType) c2;
2763 List<Type> act2 = class2.getTypeArguments();
2764 ListBuffer<Type> merged = new ListBuffer<Type>();
2765 List<Type> typarams = class1.tsym.type.getTypeArguments();
2767 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
2768 if (containsType(act1.head, act2.head)) {
2769 merged.append(act1.head);
2770 } else if (containsType(act2.head, act1.head)) {
2771 merged.append(act2.head);
2772 } else {
2773 TypePair pair = new TypePair(c1, c2);
2774 Type m;
2775 if (mergeCache.add(pair)) {
2776 m = new WildcardType(lub(upperBound(act1.head),
2777 upperBound(act2.head)),
2778 BoundKind.EXTENDS,
2779 syms.boundClass);
2780 mergeCache.remove(pair);
2781 } else {
2782 m = new WildcardType(syms.objectType,
2783 BoundKind.UNBOUND,
2784 syms.boundClass);
2785 }
2786 merged.append(m.withTypeVar(typarams.head));
2787 }
2788 act1 = act1.tail;
2789 act2 = act2.tail;
2790 typarams = typarams.tail;
2791 }
2792 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
2793 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
2794 }
2796 /**
2797 * Return the minimum type of a closure, a compound type if no
2798 * unique minimum exists.
2799 */
2800 private Type compoundMin(List<Type> cl) {
2801 if (cl.isEmpty()) return syms.objectType;
2802 List<Type> compound = closureMin(cl);
2803 if (compound.isEmpty())
2804 return null;
2805 else if (compound.tail.isEmpty())
2806 return compound.head;
2807 else
2808 return makeCompoundType(compound);
2809 }
2811 /**
2812 * Return the minimum types of a closure, suitable for computing
2813 * compoundMin or glb.
2814 */
2815 private List<Type> closureMin(List<Type> cl) {
2816 ListBuffer<Type> classes = lb();
2817 ListBuffer<Type> interfaces = lb();
2818 while (!cl.isEmpty()) {
2819 Type current = cl.head;
2820 if (current.isInterface())
2821 interfaces.append(current);
2822 else
2823 classes.append(current);
2824 ListBuffer<Type> candidates = lb();
2825 for (Type t : cl.tail) {
2826 if (!isSubtypeNoCapture(current, t))
2827 candidates.append(t);
2828 }
2829 cl = candidates.toList();
2830 }
2831 return classes.appendList(interfaces).toList();
2832 }
2834 /**
2835 * Return the least upper bound of pair of types. if the lub does
2836 * not exist return null.
2837 */
2838 public Type lub(Type t1, Type t2) {
2839 return lub(List.of(t1, t2));
2840 }
2842 /**
2843 * Return the least upper bound (lub) of set of types. If the lub
2844 * does not exist return the type of null (bottom).
2845 */
2846 public Type lub(List<Type> ts) {
2847 final int ARRAY_BOUND = 1;
2848 final int CLASS_BOUND = 2;
2849 int boundkind = 0;
2850 for (Type t : ts) {
2851 switch (t.tag) {
2852 case CLASS:
2853 boundkind |= CLASS_BOUND;
2854 break;
2855 case ARRAY:
2856 boundkind |= ARRAY_BOUND;
2857 break;
2858 case TYPEVAR:
2859 do {
2860 t = t.getUpperBound();
2861 } while (t.tag == TYPEVAR);
2862 if (t.tag == ARRAY) {
2863 boundkind |= ARRAY_BOUND;
2864 } else {
2865 boundkind |= CLASS_BOUND;
2866 }
2867 break;
2868 default:
2869 if (t.isPrimitive())
2870 return syms.errType;
2871 }
2872 }
2873 switch (boundkind) {
2874 case 0:
2875 return syms.botType;
2877 case ARRAY_BOUND:
2878 // calculate lub(A[], B[])
2879 List<Type> elements = Type.map(ts, elemTypeFun);
2880 for (Type t : elements) {
2881 if (t.isPrimitive()) {
2882 // if a primitive type is found, then return
2883 // arraySuperType unless all the types are the
2884 // same
2885 Type first = ts.head;
2886 for (Type s : ts.tail) {
2887 if (!isSameType(first, s)) {
2888 // lub(int[], B[]) is Cloneable & Serializable
2889 return arraySuperType();
2890 }
2891 }
2892 // all the array types are the same, return one
2893 // lub(int[], int[]) is int[]
2894 return first;
2895 }
2896 }
2897 // lub(A[], B[]) is lub(A, B)[]
2898 return new ArrayType(lub(elements), syms.arrayClass);
2900 case CLASS_BOUND:
2901 // calculate lub(A, B)
2902 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
2903 ts = ts.tail;
2904 Assert.check(!ts.isEmpty());
2905 //step 1 - compute erased candidate set (EC)
2906 List<Type> cl = erasedSupertypes(ts.head);
2907 for (Type t : ts.tail) {
2908 if (t.tag == CLASS || t.tag == TYPEVAR)
2909 cl = intersect(cl, erasedSupertypes(t));
2910 }
2911 //step 2 - compute minimal erased candidate set (MEC)
2912 List<Type> mec = closureMin(cl);
2913 //step 3 - for each element G in MEC, compute lci(Inv(G))
2914 List<Type> candidates = List.nil();
2915 for (Type erasedSupertype : mec) {
2916 List<Type> lci = List.of(asSuper(ts.head, erasedSupertype.tsym));
2917 for (Type t : ts) {
2918 lci = intersect(lci, List.of(asSuper(t, erasedSupertype.tsym)));
2919 }
2920 candidates = candidates.appendList(lci);
2921 }
2922 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
2923 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
2924 return compoundMin(candidates);
2926 default:
2927 // calculate lub(A, B[])
2928 List<Type> classes = List.of(arraySuperType());
2929 for (Type t : ts) {
2930 if (t.tag != ARRAY) // Filter out any arrays
2931 classes = classes.prepend(t);
2932 }
2933 // lub(A, B[]) is lub(A, arraySuperType)
2934 return lub(classes);
2935 }
2936 }
2937 // where
2938 List<Type> erasedSupertypes(Type t) {
2939 ListBuffer<Type> buf = lb();
2940 for (Type sup : closure(t)) {
2941 if (sup.tag == TYPEVAR) {
2942 buf.append(sup);
2943 } else {
2944 buf.append(erasure(sup));
2945 }
2946 }
2947 return buf.toList();
2948 }
2950 private Type arraySuperType = null;
2951 private Type arraySuperType() {
2952 // initialized lazily to avoid problems during compiler startup
2953 if (arraySuperType == null) {
2954 synchronized (this) {
2955 if (arraySuperType == null) {
2956 // JLS 10.8: all arrays implement Cloneable and Serializable.
2957 arraySuperType = makeCompoundType(List.of(syms.serializableType,
2958 syms.cloneableType),
2959 syms.objectType);
2960 }
2961 }
2962 }
2963 return arraySuperType;
2964 }
2965 // </editor-fold>
2967 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
2968 public Type glb(List<Type> ts) {
2969 Type t1 = ts.head;
2970 for (Type t2 : ts.tail) {
2971 if (t1.isErroneous())
2972 return t1;
2973 t1 = glb(t1, t2);
2974 }
2975 return t1;
2976 }
2977 //where
2978 public Type glb(Type t, Type s) {
2979 if (s == null)
2980 return t;
2981 else if (t.isPrimitive() || s.isPrimitive())
2982 return syms.errType;
2983 else if (isSubtypeNoCapture(t, s))
2984 return t;
2985 else if (isSubtypeNoCapture(s, t))
2986 return s;
2988 List<Type> closure = union(closure(t), closure(s));
2989 List<Type> bounds = closureMin(closure);
2991 if (bounds.isEmpty()) { // length == 0
2992 return syms.objectType;
2993 } else if (bounds.tail.isEmpty()) { // length == 1
2994 return bounds.head;
2995 } else { // length > 1
2996 int classCount = 0;
2997 for (Type bound : bounds)
2998 if (!bound.isInterface())
2999 classCount++;
3000 if (classCount > 1)
3001 return createErrorType(t);
3002 }
3003 return makeCompoundType(bounds);
3004 }
3005 // </editor-fold>
3007 // <editor-fold defaultstate="collapsed" desc="hashCode">
3008 /**
3009 * Compute a hash code on a type.
3010 */
3011 public static int hashCode(Type t) {
3012 return hashCode.visit(t);
3013 }
3014 // where
3015 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
3017 public Integer visitType(Type t, Void ignored) {
3018 return t.tag;
3019 }
3021 @Override
3022 public Integer visitClassType(ClassType t, Void ignored) {
3023 int result = visit(t.getEnclosingType());
3024 result *= 127;
3025 result += t.tsym.flatName().hashCode();
3026 for (Type s : t.getTypeArguments()) {
3027 result *= 127;
3028 result += visit(s);
3029 }
3030 return result;
3031 }
3033 @Override
3034 public Integer visitWildcardType(WildcardType t, Void ignored) {
3035 int result = t.kind.hashCode();
3036 if (t.type != null) {
3037 result *= 127;
3038 result += visit(t.type);
3039 }
3040 return result;
3041 }
3043 @Override
3044 public Integer visitArrayType(ArrayType t, Void ignored) {
3045 return visit(t.elemtype) + 12;
3046 }
3048 @Override
3049 public Integer visitTypeVar(TypeVar t, Void ignored) {
3050 return System.identityHashCode(t.tsym);
3051 }
3053 @Override
3054 public Integer visitUndetVar(UndetVar t, Void ignored) {
3055 return System.identityHashCode(t);
3056 }
3058 @Override
3059 public Integer visitErrorType(ErrorType t, Void ignored) {
3060 return 0;
3061 }
3062 };
3063 // </editor-fold>
3065 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
3066 /**
3067 * Does t have a result that is a subtype of the result type of s,
3068 * suitable for covariant returns? It is assumed that both types
3069 * are (possibly polymorphic) method types. Monomorphic method
3070 * types are handled in the obvious way. Polymorphic method types
3071 * require renaming all type variables of one to corresponding
3072 * type variables in the other, where correspondence is by
3073 * position in the type parameter list. */
3074 public boolean resultSubtype(Type t, Type s, Warner warner) {
3075 List<Type> tvars = t.getTypeArguments();
3076 List<Type> svars = s.getTypeArguments();
3077 Type tres = t.getReturnType();
3078 Type sres = subst(s.getReturnType(), svars, tvars);
3079 return covariantReturnType(tres, sres, warner);
3080 }
3082 /**
3083 * Return-Type-Substitutable.
3084 * @jls section 8.4.5
3085 */
3086 public boolean returnTypeSubstitutable(Type r1, Type r2) {
3087 if (hasSameArgs(r1, r2))
3088 return resultSubtype(r1, r2, Warner.noWarnings);
3089 else
3090 return covariantReturnType(r1.getReturnType(),
3091 erasure(r2.getReturnType()),
3092 Warner.noWarnings);
3093 }
3095 public boolean returnTypeSubstitutable(Type r1,
3096 Type r2, Type r2res,
3097 Warner warner) {
3098 if (isSameType(r1.getReturnType(), r2res))
3099 return true;
3100 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
3101 return false;
3103 if (hasSameArgs(r1, r2))
3104 return covariantReturnType(r1.getReturnType(), r2res, warner);
3105 if (!allowCovariantReturns)
3106 return false;
3107 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
3108 return true;
3109 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
3110 return false;
3111 warner.warn(LintCategory.UNCHECKED);
3112 return true;
3113 }
3115 /**
3116 * Is t an appropriate return type in an overrider for a
3117 * method that returns s?
3118 */
3119 public boolean covariantReturnType(Type t, Type s, Warner warner) {
3120 return
3121 isSameType(t, s) ||
3122 allowCovariantReturns &&
3123 !t.isPrimitive() &&
3124 !s.isPrimitive() &&
3125 isAssignable(t, s, warner);
3126 }
3127 // </editor-fold>
3129 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
3130 /**
3131 * Return the class that boxes the given primitive.
3132 */
3133 public ClassSymbol boxedClass(Type t) {
3134 return reader.enterClass(syms.boxedName[t.tag]);
3135 }
3137 /**
3138 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
3139 */
3140 public Type boxedTypeOrType(Type t) {
3141 return t.isPrimitive() ?
3142 boxedClass(t).type :
3143 t;
3144 }
3146 /**
3147 * Return the primitive type corresponding to a boxed type.
3148 */
3149 public Type unboxedType(Type t) {
3150 if (allowBoxing) {
3151 for (int i=0; i<syms.boxedName.length; i++) {
3152 Name box = syms.boxedName[i];
3153 if (box != null &&
3154 asSuper(t, reader.enterClass(box)) != null)
3155 return syms.typeOfTag[i];
3156 }
3157 }
3158 return Type.noType;
3159 }
3160 // </editor-fold>
3162 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3163 /*
3164 * JLS 5.1.10 Capture Conversion:
3165 *
3166 * Let G name a generic type declaration with n formal type
3167 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3168 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3169 * where, for 1 <= i <= n:
3170 *
3171 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3172 * Si is a fresh type variable whose upper bound is
3173 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3174 * type.
3175 *
3176 * + If Ti is a wildcard type argument of the form ? extends Bi,
3177 * then Si is a fresh type variable whose upper bound is
3178 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3179 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3180 * a compile-time error if for any two classes (not interfaces)
3181 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3182 *
3183 * + If Ti is a wildcard type argument of the form ? super Bi,
3184 * then Si is a fresh type variable whose upper bound is
3185 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3186 *
3187 * + Otherwise, Si = Ti.
3188 *
3189 * Capture conversion on any type other than a parameterized type
3190 * (4.5) acts as an identity conversion (5.1.1). Capture
3191 * conversions never require a special action at run time and
3192 * therefore never throw an exception at run time.
3193 *
3194 * Capture conversion is not applied recursively.
3195 */
3196 /**
3197 * Capture conversion as specified by the JLS.
3198 */
3200 public List<Type> capture(List<Type> ts) {
3201 List<Type> buf = List.nil();
3202 for (Type t : ts) {
3203 buf = buf.prepend(capture(t));
3204 }
3205 return buf.reverse();
3206 }
3207 public Type capture(Type t) {
3208 if (t.tag != CLASS)
3209 return t;
3210 if (t.getEnclosingType() != Type.noType) {
3211 Type capturedEncl = capture(t.getEnclosingType());
3212 if (capturedEncl != t.getEnclosingType()) {
3213 Type type1 = memberType(capturedEncl, t.tsym);
3214 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3215 }
3216 }
3217 ClassType cls = (ClassType)t;
3218 if (cls.isRaw() || !cls.isParameterized())
3219 return cls;
3221 ClassType G = (ClassType)cls.asElement().asType();
3222 List<Type> A = G.getTypeArguments();
3223 List<Type> T = cls.getTypeArguments();
3224 List<Type> S = freshTypeVariables(T);
3226 List<Type> currentA = A;
3227 List<Type> currentT = T;
3228 List<Type> currentS = S;
3229 boolean captured = false;
3230 while (!currentA.isEmpty() &&
3231 !currentT.isEmpty() &&
3232 !currentS.isEmpty()) {
3233 if (currentS.head != currentT.head) {
3234 captured = true;
3235 WildcardType Ti = (WildcardType)currentT.head;
3236 Type Ui = currentA.head.getUpperBound();
3237 CapturedType Si = (CapturedType)currentS.head;
3238 if (Ui == null)
3239 Ui = syms.objectType;
3240 switch (Ti.kind) {
3241 case UNBOUND:
3242 Si.bound = subst(Ui, A, S);
3243 Si.lower = syms.botType;
3244 break;
3245 case EXTENDS:
3246 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3247 Si.lower = syms.botType;
3248 break;
3249 case SUPER:
3250 Si.bound = subst(Ui, A, S);
3251 Si.lower = Ti.getSuperBound();
3252 break;
3253 }
3254 if (Si.bound == Si.lower)
3255 currentS.head = Si.bound;
3256 }
3257 currentA = currentA.tail;
3258 currentT = currentT.tail;
3259 currentS = currentS.tail;
3260 }
3261 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3262 return erasure(t); // some "rare" type involved
3264 if (captured)
3265 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3266 else
3267 return t;
3268 }
3269 // where
3270 public List<Type> freshTypeVariables(List<Type> types) {
3271 ListBuffer<Type> result = lb();
3272 for (Type t : types) {
3273 if (t.tag == WILDCARD) {
3274 Type bound = ((WildcardType)t).getExtendsBound();
3275 if (bound == null)
3276 bound = syms.objectType;
3277 result.append(new CapturedType(capturedName,
3278 syms.noSymbol,
3279 bound,
3280 syms.botType,
3281 (WildcardType)t));
3282 } else {
3283 result.append(t);
3284 }
3285 }
3286 return result.toList();
3287 }
3288 // </editor-fold>
3290 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3291 private List<Type> upperBounds(List<Type> ss) {
3292 if (ss.isEmpty()) return ss;
3293 Type head = upperBound(ss.head);
3294 List<Type> tail = upperBounds(ss.tail);
3295 if (head != ss.head || tail != ss.tail)
3296 return tail.prepend(head);
3297 else
3298 return ss;
3299 }
3301 private boolean sideCast(Type from, Type to, Warner warn) {
3302 // We are casting from type $from$ to type $to$, which are
3303 // non-final unrelated types. This method
3304 // tries to reject a cast by transferring type parameters
3305 // from $to$ to $from$ by common superinterfaces.
3306 boolean reverse = false;
3307 Type target = to;
3308 if ((to.tsym.flags() & INTERFACE) == 0) {
3309 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3310 reverse = true;
3311 to = from;
3312 from = target;
3313 }
3314 List<Type> commonSupers = superClosure(to, erasure(from));
3315 boolean giveWarning = commonSupers.isEmpty();
3316 // The arguments to the supers could be unified here to
3317 // get a more accurate analysis
3318 while (commonSupers.nonEmpty()) {
3319 Type t1 = asSuper(from, commonSupers.head.tsym);
3320 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3321 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3322 return false;
3323 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3324 commonSupers = commonSupers.tail;
3325 }
3326 if (giveWarning && !isReifiable(reverse ? from : to))
3327 warn.warn(LintCategory.UNCHECKED);
3328 if (!allowCovariantReturns)
3329 // reject if there is a common method signature with
3330 // incompatible return types.
3331 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3332 return true;
3333 }
3335 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3336 // We are casting from type $from$ to type $to$, which are
3337 // unrelated types one of which is final and the other of
3338 // which is an interface. This method
3339 // tries to reject a cast by transferring type parameters
3340 // from the final class to the interface.
3341 boolean reverse = false;
3342 Type target = to;
3343 if ((to.tsym.flags() & INTERFACE) == 0) {
3344 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3345 reverse = true;
3346 to = from;
3347 from = target;
3348 }
3349 Assert.check((from.tsym.flags() & FINAL) != 0);
3350 Type t1 = asSuper(from, to.tsym);
3351 if (t1 == null) return false;
3352 Type t2 = to;
3353 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3354 return false;
3355 if (!allowCovariantReturns)
3356 // reject if there is a common method signature with
3357 // incompatible return types.
3358 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3359 if (!isReifiable(target) &&
3360 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3361 warn.warn(LintCategory.UNCHECKED);
3362 return true;
3363 }
3365 private boolean giveWarning(Type from, Type to) {
3366 Type subFrom = asSub(from, to.tsym);
3367 return to.isParameterized() &&
3368 (!(isUnbounded(to) ||
3369 isSubtype(from, to) ||
3370 ((subFrom != null) && containsType(to.allparams(), subFrom.allparams()))));
3371 }
3373 private List<Type> superClosure(Type t, Type s) {
3374 List<Type> cl = List.nil();
3375 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3376 if (isSubtype(s, erasure(l.head))) {
3377 cl = insert(cl, l.head);
3378 } else {
3379 cl = union(cl, superClosure(l.head, s));
3380 }
3381 }
3382 return cl;
3383 }
3385 private boolean containsTypeEquivalent(Type t, Type s) {
3386 return
3387 isSameType(t, s) || // shortcut
3388 containsType(t, s) && containsType(s, t);
3389 }
3391 // <editor-fold defaultstate="collapsed" desc="adapt">
3392 /**
3393 * Adapt a type by computing a substitution which maps a source
3394 * type to a target type.
3395 *
3396 * @param source the source type
3397 * @param target the target type
3398 * @param from the type variables of the computed substitution
3399 * @param to the types of the computed substitution.
3400 */
3401 public void adapt(Type source,
3402 Type target,
3403 ListBuffer<Type> from,
3404 ListBuffer<Type> to) throws AdaptFailure {
3405 new Adapter(from, to).adapt(source, target);
3406 }
3408 class Adapter extends SimpleVisitor<Void, Type> {
3410 ListBuffer<Type> from;
3411 ListBuffer<Type> to;
3412 Map<Symbol,Type> mapping;
3414 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3415 this.from = from;
3416 this.to = to;
3417 mapping = new HashMap<Symbol,Type>();
3418 }
3420 public void adapt(Type source, Type target) throws AdaptFailure {
3421 visit(source, target);
3422 List<Type> fromList = from.toList();
3423 List<Type> toList = to.toList();
3424 while (!fromList.isEmpty()) {
3425 Type val = mapping.get(fromList.head.tsym);
3426 if (toList.head != val)
3427 toList.head = val;
3428 fromList = fromList.tail;
3429 toList = toList.tail;
3430 }
3431 }
3433 @Override
3434 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3435 if (target.tag == CLASS)
3436 adaptRecursive(source.allparams(), target.allparams());
3437 return null;
3438 }
3440 @Override
3441 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3442 if (target.tag == ARRAY)
3443 adaptRecursive(elemtype(source), elemtype(target));
3444 return null;
3445 }
3447 @Override
3448 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3449 if (source.isExtendsBound())
3450 adaptRecursive(upperBound(source), upperBound(target));
3451 else if (source.isSuperBound())
3452 adaptRecursive(lowerBound(source), lowerBound(target));
3453 return null;
3454 }
3456 @Override
3457 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3458 // Check to see if there is
3459 // already a mapping for $source$, in which case
3460 // the old mapping will be merged with the new
3461 Type val = mapping.get(source.tsym);
3462 if (val != null) {
3463 if (val.isSuperBound() && target.isSuperBound()) {
3464 val = isSubtype(lowerBound(val), lowerBound(target))
3465 ? target : val;
3466 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3467 val = isSubtype(upperBound(val), upperBound(target))
3468 ? val : target;
3469 } else if (!isSameType(val, target)) {
3470 throw new AdaptFailure();
3471 }
3472 } else {
3473 val = target;
3474 from.append(source);
3475 to.append(target);
3476 }
3477 mapping.put(source.tsym, val);
3478 return null;
3479 }
3481 @Override
3482 public Void visitType(Type source, Type target) {
3483 return null;
3484 }
3486 private Set<TypePair> cache = new HashSet<TypePair>();
3488 private void adaptRecursive(Type source, Type target) {
3489 TypePair pair = new TypePair(source, target);
3490 if (cache.add(pair)) {
3491 try {
3492 visit(source, target);
3493 } finally {
3494 cache.remove(pair);
3495 }
3496 }
3497 }
3499 private void adaptRecursive(List<Type> source, List<Type> target) {
3500 if (source.length() == target.length()) {
3501 while (source.nonEmpty()) {
3502 adaptRecursive(source.head, target.head);
3503 source = source.tail;
3504 target = target.tail;
3505 }
3506 }
3507 }
3508 }
3510 public static class AdaptFailure extends RuntimeException {
3511 static final long serialVersionUID = -7490231548272701566L;
3512 }
3514 private void adaptSelf(Type t,
3515 ListBuffer<Type> from,
3516 ListBuffer<Type> to) {
3517 try {
3518 //if (t.tsym.type != t)
3519 adapt(t.tsym.type, t, from, to);
3520 } catch (AdaptFailure ex) {
3521 // Adapt should never fail calculating a mapping from
3522 // t.tsym.type to t as there can be no merge problem.
3523 throw new AssertionError(ex);
3524 }
3525 }
3526 // </editor-fold>
3528 /**
3529 * Rewrite all type variables (universal quantifiers) in the given
3530 * type to wildcards (existential quantifiers). This is used to
3531 * determine if a cast is allowed. For example, if high is true
3532 * and {@code T <: Number}, then {@code List<T>} is rewritten to
3533 * {@code List<? extends Number>}. Since {@code List<Integer> <:
3534 * List<? extends Number>} a {@code List<T>} can be cast to {@code
3535 * List<Integer>} with a warning.
3536 * @param t a type
3537 * @param high if true return an upper bound; otherwise a lower
3538 * bound
3539 * @param rewriteTypeVars only rewrite captured wildcards if false;
3540 * otherwise rewrite all type variables
3541 * @return the type rewritten with wildcards (existential
3542 * quantifiers) only
3543 */
3544 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
3545 return new Rewriter(high, rewriteTypeVars).visit(t);
3546 }
3548 class Rewriter extends UnaryVisitor<Type> {
3550 boolean high;
3551 boolean rewriteTypeVars;
3553 Rewriter(boolean high, boolean rewriteTypeVars) {
3554 this.high = high;
3555 this.rewriteTypeVars = rewriteTypeVars;
3556 }
3558 @Override
3559 public Type visitClassType(ClassType t, Void s) {
3560 ListBuffer<Type> rewritten = new ListBuffer<Type>();
3561 boolean changed = false;
3562 for (Type arg : t.allparams()) {
3563 Type bound = visit(arg);
3564 if (arg != bound) {
3565 changed = true;
3566 }
3567 rewritten.append(bound);
3568 }
3569 if (changed)
3570 return subst(t.tsym.type,
3571 t.tsym.type.allparams(),
3572 rewritten.toList());
3573 else
3574 return t;
3575 }
3577 public Type visitType(Type t, Void s) {
3578 return high ? upperBound(t) : lowerBound(t);
3579 }
3581 @Override
3582 public Type visitCapturedType(CapturedType t, Void s) {
3583 Type bound = visitWildcardType(t.wildcard, null);
3584 return (bound.contains(t)) ?
3585 erasure(bound) :
3586 bound;
3587 }
3589 @Override
3590 public Type visitTypeVar(TypeVar t, Void s) {
3591 if (rewriteTypeVars) {
3592 Type bound = high ?
3593 (t.bound.contains(t) ?
3594 erasure(t.bound) :
3595 visit(t.bound)) :
3596 syms.botType;
3597 return rewriteAsWildcardType(bound, t);
3598 }
3599 else
3600 return t;
3601 }
3603 @Override
3604 public Type visitWildcardType(WildcardType t, Void s) {
3605 Type bound = high ? t.getExtendsBound() :
3606 t.getSuperBound();
3607 if (bound == null)
3608 bound = high ? syms.objectType : syms.botType;
3609 return rewriteAsWildcardType(visit(bound), t.bound);
3610 }
3612 private Type rewriteAsWildcardType(Type bound, TypeVar formal) {
3613 return high ?
3614 makeExtendsWildcard(B(bound), formal) :
3615 makeSuperWildcard(B(bound), formal);
3616 }
3618 Type B(Type t) {
3619 while (t.tag == WILDCARD) {
3620 WildcardType w = (WildcardType)t;
3621 t = high ?
3622 w.getExtendsBound() :
3623 w.getSuperBound();
3624 if (t == null) {
3625 t = high ? syms.objectType : syms.botType;
3626 }
3627 }
3628 return t;
3629 }
3630 }
3633 /**
3634 * Create a wildcard with the given upper (extends) bound; create
3635 * an unbounded wildcard if bound is Object.
3636 *
3637 * @param bound the upper bound
3638 * @param formal the formal type parameter that will be
3639 * substituted by the wildcard
3640 */
3641 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
3642 if (bound == syms.objectType) {
3643 return new WildcardType(syms.objectType,
3644 BoundKind.UNBOUND,
3645 syms.boundClass,
3646 formal);
3647 } else {
3648 return new WildcardType(bound,
3649 BoundKind.EXTENDS,
3650 syms.boundClass,
3651 formal);
3652 }
3653 }
3655 /**
3656 * Create a wildcard with the given lower (super) bound; create an
3657 * unbounded wildcard if bound is bottom (type of {@code null}).
3658 *
3659 * @param bound the lower bound
3660 * @param formal the formal type parameter that will be
3661 * substituted by the wildcard
3662 */
3663 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
3664 if (bound.tag == BOT) {
3665 return new WildcardType(syms.objectType,
3666 BoundKind.UNBOUND,
3667 syms.boundClass,
3668 formal);
3669 } else {
3670 return new WildcardType(bound,
3671 BoundKind.SUPER,
3672 syms.boundClass,
3673 formal);
3674 }
3675 }
3677 /**
3678 * A wrapper for a type that allows use in sets.
3679 */
3680 class SingletonType {
3681 final Type t;
3682 SingletonType(Type t) {
3683 this.t = t;
3684 }
3685 public int hashCode() {
3686 return Types.hashCode(t);
3687 }
3688 public boolean equals(Object obj) {
3689 return (obj instanceof SingletonType) &&
3690 isSameType(t, ((SingletonType)obj).t);
3691 }
3692 public String toString() {
3693 return t.toString();
3694 }
3695 }
3696 // </editor-fold>
3698 // <editor-fold defaultstate="collapsed" desc="Visitors">
3699 /**
3700 * A default visitor for types. All visitor methods except
3701 * visitType are implemented by delegating to visitType. Concrete
3702 * subclasses must provide an implementation of visitType and can
3703 * override other methods as needed.
3704 *
3705 * @param <R> the return type of the operation implemented by this
3706 * visitor; use Void if no return type is needed.
3707 * @param <S> the type of the second argument (the first being the
3708 * type itself) of the operation implemented by this visitor; use
3709 * Void if a second argument is not needed.
3710 */
3711 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
3712 final public R visit(Type t, S s) { return t.accept(this, s); }
3713 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
3714 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
3715 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
3716 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
3717 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
3718 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
3719 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
3720 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
3721 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
3722 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
3723 }
3725 /**
3726 * A default visitor for symbols. All visitor methods except
3727 * visitSymbol are implemented by delegating to visitSymbol. Concrete
3728 * subclasses must provide an implementation of visitSymbol and can
3729 * override other methods as needed.
3730 *
3731 * @param <R> the return type of the operation implemented by this
3732 * visitor; use Void if no return type is needed.
3733 * @param <S> the type of the second argument (the first being the
3734 * symbol itself) of the operation implemented by this visitor; use
3735 * Void if a second argument is not needed.
3736 */
3737 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
3738 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
3739 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
3740 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
3741 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
3742 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
3743 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
3744 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
3745 }
3747 /**
3748 * A <em>simple</em> visitor for types. This visitor is simple as
3749 * captured wildcards, for-all types (generic methods), and
3750 * undetermined type variables (part of inference) are hidden.
3751 * Captured wildcards are hidden by treating them as type
3752 * variables and the rest are hidden by visiting their qtypes.
3753 *
3754 * @param <R> the return type of the operation implemented by this
3755 * visitor; use Void if no return type is needed.
3756 * @param <S> the type of the second argument (the first being the
3757 * type itself) of the operation implemented by this visitor; use
3758 * Void if a second argument is not needed.
3759 */
3760 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
3761 @Override
3762 public R visitCapturedType(CapturedType t, S s) {
3763 return visitTypeVar(t, s);
3764 }
3765 @Override
3766 public R visitForAll(ForAll t, S s) {
3767 return visit(t.qtype, s);
3768 }
3769 @Override
3770 public R visitUndetVar(UndetVar t, S s) {
3771 return visit(t.qtype, s);
3772 }
3773 }
3775 /**
3776 * A plain relation on types. That is a 2-ary function on the
3777 * form Type × Type → Boolean.
3778 * <!-- In plain text: Type x Type -> Boolean -->
3779 */
3780 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
3782 /**
3783 * A convenience visitor for implementing operations that only
3784 * require one argument (the type itself), that is, unary
3785 * operations.
3786 *
3787 * @param <R> the return type of the operation implemented by this
3788 * visitor; use Void if no return type is needed.
3789 */
3790 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
3791 final public R visit(Type t) { return t.accept(this, null); }
3792 }
3794 /**
3795 * A visitor for implementing a mapping from types to types. The
3796 * default behavior of this class is to implement the identity
3797 * mapping (mapping a type to itself). This can be overridden in
3798 * subclasses.
3799 *
3800 * @param <S> the type of the second argument (the first being the
3801 * type itself) of this mapping; use Void if a second argument is
3802 * not needed.
3803 */
3804 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
3805 final public Type visit(Type t) { return t.accept(this, null); }
3806 public Type visitType(Type t, S s) { return t; }
3807 }
3808 // </editor-fold>
3811 // <editor-fold defaultstate="collapsed" desc="Annotation support">
3813 public RetentionPolicy getRetention(Attribute.Compound a) {
3814 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
3815 Attribute.Compound c = a.type.tsym.attribute(syms.retentionType.tsym);
3816 if (c != null) {
3817 Attribute value = c.member(names.value);
3818 if (value != null && value instanceof Attribute.Enum) {
3819 Name levelName = ((Attribute.Enum)value).value.name;
3820 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
3821 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
3822 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
3823 else ;// /* fail soft */ throw new AssertionError(levelName);
3824 }
3825 }
3826 return vis;
3827 }
3828 // </editor-fold>
3829 }
